Antistatic knitwear and antistatic clothing

Abstract

Antistatic knitted fabric is provided that is inexpensive, durable, and can ensure the required antistaticity. This antistatic knitted fabric is knitted such that a plurality of non-conductive yarn rows 1 made of a non-conductive yarn and one or more conductive yarn rows 2A and 2B made of the conductive yarns alternate with each other. The conductive yarn is a cover yarn 20 formed by winding an organic fiber yarn 22 around a tungsten yarn 21 as the core yarn. The pitch between two adjacent conductive yarn rows 2A and 2B is 2.3-7 mm, and the number of turns of the organic fiber yarn 22 per unit length in the cover yarn is 600-1200 times / m.

Description

TECHNICAL FIELD

[0001] The present invention relates to antistatic knitted fabrics and antistatic clothing made from antistatic knitted fabrics. TECHNICAL BACKGROUND

[0002] Japanese Patent No. 5432841 (Patent Document 1) discloses work knitwear containing conductive fibers.

[0003] Furthermore, Japanese Patent No. 6487228 (Patent Document 2) discloses flame-retardant and antistatic fabrics composed of flame-retardant fiber yarns and conductive composite yarns. This patent also discloses that the fabrics include woven fabrics and knitted fabrics in which conductive composite yarns are arranged in a lattice pattern with spaces between them. PRIOR ART PATENTS Patent Document 1: Japanese Patent No. 5432841 Patent Document 2: Japanese Patent No. 6487228 SUMMARY OF THE INVENTIONTechnical Problem

[0004] According to the description in Patent Document 1, woven fabrics or knitted fabrics are textiles comprising textiles made from woven fabrics or knitted fabrics. However, Patent Document 1 does not describe embodiments of knitted fabrics containing conductive fiber yarns.

[0005] Furthermore, according to the specification of Patent Document 2, the textile fabrics include knitted fabrics, including circular knits. However, Patent Document 2 does not contain any specific embodiments using circular knits. Since, according to the claims of Patent Document 2, the textile fabric is made of conductive composite yarns arranged in a grid pattern with spaces between them, it is clear that the textile fabrics described in Patent Document 2 do not include knitted fabrics in which the yarns are not arranged in a grid pattern.

[0006] Publicly known documents, including Patent Documents 1 and 2, contain descriptions of antistatic textiles made of knitted fabrics with conductive yarns, but in reality, there is no specific disclosure. Since knitted fabrics, such as circular knits, are stretchable, they are used for workwear, sportswear, and other items requiring durability. However, in knitted fabrics, so-called conductive fibers cannot be arranged in a grid pattern, so a large amount of conductive yarn must be used to ensure the necessary antistatic properties, leading to the problem of high prices for antistatic knitted fabrics. Furthermore, when metal wires are used as conductive yarns, repeated washing may cause breakage, which may reduce the antistatic properties and prematurely deteriorate durability.

[0007] An object of the present invention is to provide an antistatic knitted fabric which is inexpensive and durable, while providing the necessary antistatic properties.

[0008] Another object of the present invention is to provide antistatic clothing that is inexpensive and has high antistatic performance. SOLUTION TO THE PROBLEM

[0009] The present invention is directed to antistatic knitted fabric composed of non-conductive yarns and conductive yarns. The antistatic knitted fabric according to the invention is a knitted fabric knitted in such a way that a plurality of non-conductive yarn rows made of the non-conductive yarns and one or more conductive yarn rows made of the conductive yarns alternate. The conductive yarn is a cover yarn formed by winding an organic fiber yarn around a tungsten yarn as the core yarn.

[0010] Since the tungsten yarn exhibits excellent conductivity, the desired conductivity and durability can be achieved with a small number of conductive yarn courses. Furthermore, the cover yarn exhibits the desired electrical conductivity and durability by selecting an appropriate number of organic fiber yarn turns per unit length. Therefore, using the cover yarn in the antistatic knit fabric, the necessary conductivity and durability can be ensured. Reducing the number of organic fiber yarn turns per unit length of the cover yarn increases the electrical resistance value on the surface of the antistatic knit fabric, and the antistatic performance improves.However, with a reduction in the number of turns of the organic fiber yarn per unit length, the covering effect decreases, and due to the bending and twisting forces exerted during washing, the tungsten yarn, which forms the core wire of the conductive yarn, is more likely to be damaged or broken. Even if the electrical resistance value at the surface can be reduced, the electrical resistance value at the surface increases after washing, even after a small number of washes, leading to the problem of premature deterioration of the antistatic performance.When the conditions of the present invention are satisfied, the electrical resistance value at the surface required for the antistatic effect can be ensured without increasing the number of conductive yarns more than necessary, and an antistatic knitted fabric having the necessary durability and antistatic performance can be provided at a low cost.

[0011] Specifically, the distance (pitch) between two adjacent conductive yarn rows of the one or more conductive yarns is preferably 2.3 mm to 7 mm. The fineness of the organic fiber is preferably 20 to 100 denier, and the number of turns of the organic fiber yarn per unit length in the cover yarn is preferably 600 to 1200 times / m. In this case, the wire diameter of the tungsten yarn is preferably 30 μm or less. With a wire diameter of the tungsten yarn larger than this diameter, the tungsten yarn is more likely to be exposed to the surface of the conductive yarn, making it easier to achieve higher conductivity than desired. These conditions have been confirmed by tests.

[0012] In particular, the one or more conductive yarn rows consist of a conductive yarn row, and the wire diameter of the tungsten yarn is preferably 16 µm to 22 µm. With a wire diameter of the tungsten yarn of 22 µm or less, the prickly feeling caused by tungsten with its high hardness can be avoided. In addition, with a wire diameter of the tungsten yarn of less than 16 µm, the electrical resistance of the tungsten yarn exceeds 100 Ω / 30 cm, so the electrical resistance of the conductive yarn is on the order of 10 11 Ω / 30 cm after 50 washes.

[0013] When using hydrophilic organic fiber yarns such as nylon, the organic fiber yarn 22 preferably has a fineness of 70 to 80 denier.

[0014] If the knitwear is circularly knitted, at least the conductive yarn rows are preferably half-knitted. Half-knitting reduces the number of stitches, which results in fewer bends in the tungsten yarn and further increases durability.

[0015] Antistatic clothing made with the antistatic knitwear according to the invention has very good antistatic properties, is inexpensive and has high durability. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A and Fig. 1B are schematic diagrams for explaining the structure of a cover yarn formed by double winding an organic fiber yarn around a tungsten yarn as a core yarn. Fig. Figure 2 is a schematic diagram explaining the structure of a knitted fabric in which the conductive yarn portion of the row is half-knitted. Fig. Figure 3 is a graph showing the results of experiments conducted on an example and a comparative example. DESCRIPTION OF EMBODIMENTS

[0016] The following is a detailed description of one embodiment of the present invention. The antistatic knitted fabric according to the embodiment is essentially an antistatic knitted fabric knitted by circular knitting with non-conductive yarns and conductive yarns. The non-conductive yarn constitutes the base yarn. The antistatic knitted fabric according to the embodiment is a knitted fabric knitted by circular knitting such that a plurality of non-conductive yarn rows made of non-conductive yarns and one or more conductive yarn rows made of conductive yarns alternate with each other at intervals (a predetermined pitch).

[0017] As in Fig. 1A and Fig. As shown in FIG. 1B, the conductive yarn is a cover yarn 20 formed by winding an organic fiber yarn 22 around a tungsten yarn 21 as a core yarn. Specifically, the cover yarn 20 constituting the conductive yarn is produced by stretching and fixing the tungsten yarn 21 and spirally winding the organic fiber yarn 22 as a sheath yarn in one or more layers around the tungsten yarn 21 (i.e., performing a covering process). Fig. 1A and Fig. 1B shows an example of a double winding.

[0018] As in Fig. 1A, the organic fiber yarn 22 is wound with a space between each turn. From a macroscopic point of view, a portion of the tungsten yarn 21 is exposed. In reality, the organic fiber yarn 22 is thinner than the tungsten yarn and has thin branches arranged around it, so that the thick tungsten yarn of the cover yarn is covered with thin, fluffy organic fiber yarn and is thus not visible. From an electrical point of view, however, there are many exposed areas where the surface of the tungsten yarn is partially exposed. The surface resistance of the knitted fabric is determined by the amount of exposed areas and the spacing between the conductive yarn rows made from the cover yarn.

[0019] In the embodiment, the preferred number of turns of the organic fiber yarn 22 per unit length (the number of times the organic fiber yarn is wound in a single or double spiral around 1 m of the core yarn) is 600 to 1200 times / m.

[0020] For example, the tungsten yarn is manufactured as follows. First, a material made of tungsten powder with a particle size of 5 μm each is pressed into an ingot and sintered. Next, the tungsten ingot undergoes a die forging process in which the ingot is expanded from all sides while being forged and compressed, thus forming a wire. Wire drawing is then performed using wire drawing dies. Wire drawing is performed using wire drawing dies with different hole diameters in a sequence in which the hole diameter gradually decreases. The wire diameter of the tungsten yarn 21 produced in this way used in the embodiment is 30 μm or less, and its surface roughness Ra is 0.20 or less. Specifically, the purity of tungsten in the tungsten yarn is 99.9% or more. The purity of tungsten in the tungsten yarn may be 95% or more, but is not limited to this.The tungsten yarn 21 can be designed with a smaller diameter and has the property of being difficult to break or tear even when repeatedly bent or twisted.

[0021] The organic fiber yarn 22 is not particularly limited and may be a polyester yarn, a polyethylene yarn, a polyurethane yarn, a polyvinyl chloride yarn, an acrylic yarn, or the like having hydrophobic properties. Nylon or the like having hydrophilic properties may also be used. The specific organic fiber yarn 22 used in the embodiment is a polyester yarn with a fineness of 75 denier. When the fineness of the organic fiber yarn 22 is sufficiently small, the flexibility of the organic fiber yarn 22 increases, making it more pliable. This makes the covering process easier to perform. The cover yarn 20 used in the embodiment has excellent durability, so that the necessary durability can be ensured when used in the knitted fabric.

[0022] In particular, in the antistatic knitted fabric according to the embodiment as shown in Fig. 2, a plurality of non-conductive yarn courses 1 made of non-conductive yarns 10 and conductive yarn courses 2A, 2B made of a conductive yarn are knitted by half-knitting in a circular knitting such that the conductive yarn courses 2A, 2B alternate with each other at intervals (at a predetermined pitch). When the knitted fabric is knitted by circular knitting, preferably at least the conductive yarn courses are knitted by half-knitting, as in the embodiment. With half-knitting, the number of loops is reduced, thereby reducing the number of bent portions of the tungsten yarn and further increasing durability.

[0023] In the embodiment, the distance (pitch) between two adjacent conductive yarn rows and the number of turns per unit length of the organic fiber yarn 22 in the cover yarn 20 are selected such that the surface resistance of the knitted fabric after at least 50 washing cycles is in the range between n×10 11 Ω / 30 cm or more (1 <n<10) und m×10 11 Ω / 30 cm or less (1 <n<m<10) liegt. Wenn der Oberflächenwiderstand im Bereich von 10 9 up to 10 11 Ω or less, the antistatic function is demonstrated. Below this range, the conductivity is high and the function of quickly dissipating static electricity is demonstrated. When the surface resistance exceeds this range, the electrical insulation increases, charging occurs, and the antistatic function is reduced.

[0024] Specifically, in the case of the knitted fabric according to the embodiment, the distance (pitch) between adjacent conductive yarn rows 2A and 2B is 2.3 mm to 7 mm, and the number of turns per unit length of the organic fiber yarn 22 in the cover yarn 20 is 600 to 1200 times / m. Within these ranges, the required antistatic performance can be achieved. The shorter the distance (pitch) between the conductive yarn rows 2A and 2B, the smaller the surface resistance value and the higher the antistatic effect, but the price of the knitted fabric increases because the amount of expensive conductive yarn used increases. In addition, the smaller the number of turns per unit length of the organic fiber yarn 22 in the cover yarn 20, the more the tungsten yarn 21 is exposed, the smaller the surface resistance value, and the higher the antistatic effect.However, with a reduced number of turns per unit length of the organic fiber yarn 22, the amount of exposed tungsten yarn 21 increases, and the surface resistance of the knitted fabric with the conductive yarn becomes too low, resulting in a short circuit and significantly impairing its practical usability as antistatic clothing. For these reasons, antistatic clothing that can provide antistatic performance with knitted fabric and also ensure the necessary durability has not been used in practice to date.

[0025] The inventors have therefore developed the antistatic knitted fabric of the present invention, which is inexpensive and highly durable and offers practically usable antistatic performance. [Example]

[0026] In the following, examples in which the effects of the present invention were confirmed are described with reference to the Fig. The test results shown in Figure 3 are described. Fig. 3 shows the experimental results of some examples in which the number of turns per unit length of the organic fiber yarn 22 and the distance (pitch) between the conductive yarn row 2A and the conductive yarn row 2B are changed.

[0027] In the examples from Fig. 3, the wire diameter of the tungsten yarn 21 used as the conductive yarn in the cover yarn 20 and the fineness of the organic fiber yarn 22 are unchanged. The tungsten yarn used has a wire diameter of 20 μm. The organic fiber yarn 22 was a 75-denier hydrophobic polyester fiber yarn or a 75-denier hydrophilic nylon fiber yarn. The non-conductive yarn 10 was a 75-denier polyester fiber yarn. The conductive yarn rows (2A, 2B) consisted of a conductive yarn. A conductive yarn and a non-conductive yarn were combined to change the interval (pitch) between two adjacent conductive yarn rows (2A, 2B) (changing the number of non-conductive yarn rows 1), and a semi-knitted fabric was produced by circular knitting.A garment (like a T-shirt) was made from the knitted fabric for measurement. The pitch is the distance between the centers of the conductive yarn rows (2A, 2B). A short pitch increases the number of conductive yarns, resulting in higher costs; on the other hand, a long pitch decreases the number of conductive yarns, but also reduces the antistatic performance. Therefore, the pitch must be determined appropriately.

[0028] In particular, in examples 1 to 6 in Fig. 3 The distance (pitch) between the adjacent conductive yarn rows 2A and 2B is 2.5 mm and 7 mm, and the number of turns per unit length of the organic fiber yarn 22 is 1200 times / m and 600 times / m. In the column "Material" in Fig. 3 "PEs" stands for polyester and "Ny" for nylon. "Yes" or "No" in the "Antistatic" column indicates whether the knitwear has been subjected to antistatic treatment, in which an antistatic agent is applied to the knitwear to prevent static electricity from accumulating on the surface of the knitwear. It should be noted that the antistatic agent will peel off and lose its effectiveness after repeated washing, so performing the antistatic treatment is optional. The "0 Washes" column indicates the measured surface resistance value before washing. It should be noted that the surface resistance value indicates the maximum resistance value obtained by measuring the surface resistance values ​​"between the right sleeve and the right front", "between the front and back", and "between the right sleeve and left sleeve" for the test garment.The distance between the two measuring electrodes was 30 cm, and the measurement method was in accordance with JIS L 1930. The columns "50 washes" and "100 washes" indicate the surface resistance values ​​measured using the same measurement method as above after 50 and 100 repeated washes, respectively, according to the JIS L 1930 4M method. A surface resistance value of less than 10. 11 Ω can be evaluated to indicate that the surface has antistatic performance, where no static electricity is charged. On the other hand, if the surface resistance value is in the range of 10 12 Ω, this is considered to mean that the surface begins to charge with static electricity and the antistatic performance begins to deteriorate. If the surface resistance value is less than 10 2Ω there is a risk of electric shock due to discharge, but unless the textile is a knitted fabric consisting mainly of conductive fibers, such a surface resistance value will not be reached. If the value in the “Separation” column is Fig. 3 "Yes," this means that the tungsten yarn exposed between the organic fiber yarns 22 of the cover yarn 20 is partially separated, or that the surface of the tungsten yarn is torn into small pieces or decomposed to such an extent that the surface resistance value is significantly increased even though the tungsten yarn is not separated. "Separation" is assessed based on an electron micrograph of the surface of the tungsten yarn exposed between the organic fiber yarns 22 of the cover yarn 20 and the surface resistance value after 100 wash cycles.

[0029] From the results of examples 1 to 6 in Fig.3, when the distance (pitch) between adjacent conductive yarn rows 2A and 2B is set to 2.5 mm to 7 mm and the number of turns per unit length of the organic fiber yarn 22 in the cover yarn 20 is set to 600 to 1200 times / m, the surface resistance value after “50 washes” is in the order of 10 11 Ω, and even after 100 washes, the surface resistance value is not so high that breakage can be detected. Therefore, it was confirmed that the necessary antistatic properties and durability can be achieved without increasing the amount of conductive yarn used.

[0030] With a pitch shorter than 2.5 mm, the antistatic performance is not higher than necessary, and with a pitch longer than 7.0 mm, the surface resistance becomes too high and the necessary antistatic performance is not achieved.

[0031] Through experiments, it was found that a practically usable antistatic knitted fabric can be obtained by forming one or more conductive yarn rows into one conductive yarn row, selecting 1100 to 1200 turns / m as the number of turns per unit length, and selecting 2.5 to 3.0 mm as the pitch.

[0032] Furthermore, if the number of turns per unit length is reduced to less than 200 turns / m, the surface resistance becomes too low, making it easier to cause electric shock due to discharge. If the number of turns per unit length is set to 1,300 turns / m, for example, the surface resistance becomes too low even with a short pitch, making it impossible to achieve the required antistatic performance. INDUSTRIAL APPLICABILITY

[0033] With the present invention, the surface resistance required for an antistatic effect can be ensured without increasing the number of conductive yarns more than necessary, and an antistatic knitted fabric having the necessary durability and antistatic properties can be provided at a low cost. EXPLANATION OF REFERENCE SYMBOLS 1 Non-conductive yarn rows 2A, 2B Conductive yarn rows 10 Non-conductive yarn 20 Cover yarn (conductive yarn) 21 tungsten yarn 22 organic fiber yarn QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 5432841 [0002, 0003] JP 6487228

[0003]

Claims

[1] An antistatic knitted fabric made of non-conductive yarns and conductive yarns, comprising a knitted fabric knitted such that a plurality of non-conductive yarn rows made of the non-conductive yarns and one or more conductive yarn rows made of the conductive yarns alternate with each other; wherein the conductive yarn is a cover yarn formed by winding an organic fiber yarn around a tungsten yarn as a core yarn; a distance between two adjacent conductive yarn rows of the one or more conductive yarns is 2.3 mm to 7 mm and the number of turns of the organic fiber yarn per unit length in the cover yarn is 600 to 1200 times / m. [2] The antistatic knitted fabric according to claim 1, wherein a diameter of the tungsten yarn is 16 µm to 22 µm and the organic fiber yarn has a fineness of 20 to 100 denier. [3] The antistatic knitted fabric according to claim 1, wherein the organic fiber yarn has a hydrophobic surface of the organic fiber yarn having an antistatic structure. [4] Antistatic knitted fabric according to claim 3, wherein the one or more conductive yarn rows are each formed from a conductive yarn row, the number of turns of the organic fibre yarn per unit length is 1100 to 1200 times / m and the distance is 2.5 to 3.0 mm. [5] The antistatic knitted fabric according to claim 2, wherein the organic fiber yarn is a hydrophilic organic fiber yarn. [6] Antistatic knitted fabric according to any one of claims 1 to 5, wherein the knitted fabric is knitted by circular knitting. [7] Antistatic knitted fabric according to claim 6, wherein the circular knitting includes half-knitting of at least the conductive yarn courses. [8] Antistatic clothing made using the antistatic knitted fabric according to claim 7.

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