WO2024135753A1 - Antistatic knitted fabric and antistatic garment - Google Patents

Abstract

Provided is an antistatic knitted fabric which is inexpensive, has durability, and can ensure required antistaticity. This antistatic knitted fabric is a knitted fabric obtained by knitting a plurality of non-conductive yarn rows 1 composed of a non-conductive yarn and at least one conductive yarn row 2A and at least one conductive yarn row 2B composed of a conductive yarn so as to alternately appear. The conductive yarn is a covering yarn 20 obtained by using a tungsten yarn 21 as a core yarn and winding an organic fiber yarn 22 around the tungsten yarn 21. The distance between the at least one conductive yarn row 2A and the at least one conductive yarn row 2B, which are adjacent, is 2.3-7 mm, and the unit winding number of the organic fiber yarn 22 of the covering yarn is 600-1,200 times/m.

Description

Antistatic knitted fabric and antistatic clothing

The present invention relates to antistatic knitted fabric and antistatic clothing made from antistatic knitted fabric.

　Japanese Patent Publication No. 5432841 (Patent Document 1) discloses a knitted work fabric that contains conductive fibers.

Furthermore, Japanese Patent No. 6487228 (Patent Document 2) discloses a flame-retardant, antistatic fabric that is composed of flame-retardant fiber yarn and conductive composite yarn. It is described that this fabric includes woven fabrics and knitted fabrics in which conductive composite yarns are arranged in a lattice pattern with spaces between them.

Patent No. 5432841 Patent No. 6487228

Patent Document 1 describes woven or knitted fabrics as fabrics, but does not provide any specific examples of knitted fabrics that contain conductive fiber yarns.

In addition, although Patent Document 2 states that the fabrics include knitted fabrics, including circular knitted fabrics, there are no specific examples that use circular knitted fabrics. Since the claims of Patent Document 2 state that the conductive composite yarns are arranged in a grid pattern with spaces between them, it is clear that Patent Document 2 does not include knitted fabrics in which the yarns are not arranged in a grid pattern.

Publicly known documents, including Patent Documents 1 and 2, contain descriptions of antistatic fabrics made of knitted fabrics containing conductive yarns, but the reality is that there is no specific disclosure. Knitted fabrics, such as circular knitted fabrics, are stretchy and are therefore used in fabrics such as workwear and sportswear that require durability. However, in knitted fabrics, so-called conductive fibers cannot be arranged in a lattice pattern, so in order to ensure the necessary antistatic properties, a large amount of conductive yarn must be used, which results in a problem of high prices for antistatic knitted fabrics. In addition, if metal wires are used as conductive yarns, repeated washing can cause breaks, which can lead to a decrease in antistatic properties and early deterioration in durability.

The object of the present invention is to provide an antistatic knitted fabric that is inexpensive, durable, and yet provides the necessary antistatic properties.

Another object of the present invention is to provide antistatic clothing that is inexpensive and has high antistatic performance.

The present invention is directed to an antistatic knitted fabric constructed using nonconductive yarn and conductive yarn. The antistatic knitted fabric of the present invention is a knitted fabric woven so that multiple rows of nonconductive yarns made of nonconductive yarns and one or more rows of conductive yarns made of conductive yarns appear alternately. The conductive yarn is a covering yarn made of a tungsten yarn as a core yarn around which an organic fiber yarn is wrapped.

Since tungsten yarn has excellent conductivity, it is possible to secure the desired conductivity and durability with a small number of conductive yarn rows. Furthermore, by appropriately selecting the number of unit windings of the covering yarn, the covering yarn can exhibit the desired conductivity and durability. Therefore, when the covering yarn is used in an antistatic knitted fabric, the necessary conductivity and durability can be secured. If the number of unit windings of the organic fiber yarn of the covering yarn is reduced, the surface resistance value of the antistatic knitted fabric decreases and the antistatic performance improves. However, if the number of unit windings of the organic fiber yarn is reduced, the covering effect decreases, and the tungsten yarn, which is the core wire of the conductive yarn, becomes more likely to be damaged or broken due to the bending stress and twisting force applied during washing. As a result, even if the surface resistance value before washing can be reduced, the surface resistance value after washing increases at a stage where the number of washings is small, causing a problem of early deterioration of the antistatic performance. If the conditions of the present invention are satisfied, the surface resistance value required for antistatic can be secured without increasing the number of conductive yarns more than necessary, and an antistatic knitted fabric with the necessary durability and antistatic performance can be provided at a low cost.

Specifically, the distance (pitch) between two adjacent rows of one or more conductive threads is preferably 2.3 mm to 7 mm. The fineness of the organic fiber is preferably 20 to 100 denier, and the number of unit windings of the organic fiber thread of the covering thread is preferably 600 to 1200 times/m. In this case, the wire diameter of the tungsten thread is preferably 30 μm or less. If the wire diameter is thicker than this, the tungsten will be more likely to come out onto the surface of the conductive thread, making it easier to achieve conductivity above the desired level. These conditions have been confirmed by testing.

In particular, the one or more conductive thread rows are composed of one conductive thread row, and the diameter of the tungsten thread is preferably 16 μm to 22 μm. If the tungsten thread is 22 μm or less, it is possible to suppress the prickly feeling caused by tungsten, which has a high hardness. Furthermore, if the tungsten thread is thinner than 16 μm, the electrical resistance of the tungsten thread exceeds 100 Ω/30 cm, and therefore the resistance of the conductive thread may exceed the order of ¹⁰ Ω/30 cm after 50 washes.

When using hydrophilic organic fibers such as nylon, it is preferable that the organic fiber thread 22 has a fineness of 70 to 80 denier.

If the knitted fabric is circularly knitted, it is preferable that at least the rows of conductive yarn are half-knitted. Half-knitted knitting reduces the number of stitches, which means fewer bends in the tungsten yarn and further increases durability.

Antistatic clothing manufactured using the antistatic knitted fabric of the present invention has excellent antistatic properties, and is inexpensive and highly durable.

1A and 1B are schematic diagrams for explaining the structure of a covering yarn in which a tungsten yarn is used as a core yarn and an organic fiber yarn is wound twice around the core yarn. This is a schematic diagram used to explain the structure of a knitted fabric in which the conductive yarn row portion is half-knitted. FIG. 13 is a diagram showing the results of experiments performed on an example and a comparative example.

The following is a detailed description of an embodiment of the present invention. The antistatic knitted fabric of this embodiment is basically an antistatic knitted fabric that is circularly knitted using nonconductive yarn and conductive yarn. The nonconductive yarn constitutes the ground yarn. The antistatic knitted fabric of this embodiment is a knitted fabric that is circularly knitted so that multiple rows of nonconductive yarns made of nonconductive yarns and one or more rows of conductive yarns made of conductive yarns appear alternately at intervals (a predetermined distance).

As shown in Figures 1(A) and (B), the conductive thread is a covering thread 20 made by winding an organic fiber thread 22 around a tungsten thread 21 as a core thread. Specifically, the tungsten thread 21 is stretched and fixed, and the organic fiber thread 22 is wound around the tungsten thread 21 as a sheath thread in a single or multiple helical fashion (i.e., a covering process is performed), to produce the covering thread 20 that constitutes the conductive thread. Figures 1(A) and (B) show an example of double winding.

As shown diagrammatically in FIG. 1(A), the organic fiber yarn 22 is spaced apart for each turn. From a macroscopic perspective, 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 around it, so the covering yarn is invisible as the thick tungsten yarn is covered by the thin, fluffy organic fiber yarn. However, from an electrical perspective, there are exposed areas where the surface of the tungsten yarn is partially exposed in many places. The surface resistance of the knitted fabric is determined by the amount of exposed area and the distance between the rows of conductive yarn made of the covering yarn.

In this embodiment, the preferred unit number of windings of the organic fiber yarn 22 (the number of times the organic fiber yarn is wound in a single or double spiral shape around 1 m of the core yarn) is 600 to 1200 times/m.

The tungsten thread is made by, for example, pressing and sintering tungsten powder with a particle size of 5 μm into an ingot. Next, the ingotized tungsten block is subjected to a swaging process in which the ingot is forged and compressed from the periphery and then stretched to form a wire. After that, wire drawing (wire drawing) is performed using a wire drawing die. Wire drawing is performed by using multiple wire drawing dies with different hole diameters in the order of gradually decreasing hole diameters. The wire diameter of the tungsten thread 21 used in this embodiment made in this manner is 30 μm or less, and the surface roughness Ra is 0.20 or less. Specifically, the purity of the tungsten thread is 99.9% or more. The purity of the tungsten thread may be 95% or more, but is not limited to this. The tungsten thread 21 can be made smaller in diameter, and has the property of being difficult to break or rupture even when repeatedly bent or twisted.

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, which has hydrophobic properties. Nylon, or the like, which has hydrophilic properties, may also be used. The specific organic fiber yarn 22 used in this embodiment is a polyester yarn with a fineness of 75 denier. If the fineness of the organic fiber yarn 22 is sufficiently small, the flexibility of the organic fiber yarn 22 increases, making it easier to bend. This makes it easier to perform the covering process. The covering yarn 20 used in this embodiment has excellent durability, so when used in knitted fabric, the necessary durability can be ensured.

In particular, in the antistatic knitted fabric of this embodiment, as shown in FIG. 2, multiple non-conductive yarn rows 1 made of non-conductive yarns 10 and conductive yarn rows 2A, 2B made of a single conductive yarn are knitted in a half-knit circular manner so that they alternate at intervals (a predetermined distance or pitch). If the knitted fabric is knitted in a circular manner, it is preferable that at least the conductive yarn rows are knitted in a half-knit manner, as in this embodiment. With half-knit knitting, the number of stitches is reduced, which reduces the number of bent portions of the tungsten yarn and further increases durability.

In this embodiment, the distance (pitch) between two adjacent rows of conductive yarns and the number of unit windings of the organic fiber yarn 22 of the covering yarn 20 are determined so that the surface resistance of the knitted fabric after at least ⁵⁰ washes is in the range of n×10 ¹¹ Ω/30 cm or more (1<n<10) and m×10 11 Ω/30 cm or less (1<n<m<10). If the surface resistance is in the range of 10 ⁹ to 10 ¹¹ Ω or less, the antistatic function is exhibited, and below this range, the conductivity is high and the function of quickly dissipating static electricity is exhibited. If the surface resistance exceeds this range, the insulating property becomes high, charging occurs, and the antistatic function is reduced.

In the case of the circular knitted fabric of this embodiment, specifically, the distance (pitch) between adjacent conductive thread rows 2A and 2B is 2.3 mm to 7 mm, and the number of unit windings of the organic fiber yarn 22 of the covering yarn 20 is 600 to 1200 times/m. Within these ranges, the required antistatic performance can be obtained. The shorter the distance (pitch) between the conductive thread rows 2A and 2B, the smaller the surface resistance value and the higher the antistatic effect (antistatic effect), but the price of the knitted fabric will increase because the amount of expensive conductive yarn used will increase. Also, the fewer the number of unit windings of the organic fiber yarn 22 of the covering yarn 20, the more exposed the tungsten yarn 21 will be, the smaller the surface resistance value and the higher the antistatic effect. However, if the number of times the organic fiber yarn 22 is wrapped around a unit is reduced, the amount of exposed tungsten yarn 21 increases, and the surface resistance of the knitted fabric using the conductive yarn becomes too low, causing a short circuit and significantly impairing its practicality as an antistatic garment. For these reasons, in practice, antistatic garments that can exert antistatic performance with knitted fabric and also ensure the necessary durability have not been put into practical use.

The inventors therefore developed the antistatic knitted fabric of the present invention, which is inexpensive, highly durable, and exhibits antistatic performance that can be put to practical use.

[Example]
Hereinafter, examples in which the effects of the present invention have been confirmed will be described based on the experimental results shown in Fig. 3. Fig. 3 shows the experimental results of a number of examples in which the unit number of windings of the organic fiber yarn 22 and the distance (pitch) between the conductive yarn row 2A and the conductive yarn row 2B are changed.

In the embodiment of FIG. 3, the wire diameter of the tungsten yarn 21 used in the covering yarn 20 as the conductive yarn is the same as the fineness of the organic fiber yarn 22. The tungsten yarn used had a wire diameter of 20 μm. The organic fiber yarn 22 was a hydrophobic polyester fiber yarn with a fineness of 75 denier or a hydrophilic nylon fiber yarn with a fineness of 75 denier. The non-conductive yarn 10 was a polyester fiber yarn with a fineness of 75 denier. The conductive yarn row (2A, 2B) was composed of one 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 half-knitted knitted fabric was made by circular knitting. The knitted fabric was used to make a garment (T-shirt type) for measurement. The pitch is the distance between the centers of the conductive yarn rows (2A, 2B). If the pitch is short, the number of conductive threads increases, resulting in higher costs, while if the pitch is long, the number of conductive threads decreases, but the antistatic performance decreases. Therefore, the pitch must be determined appropriately.

Specifically, in Examples 1 to 6 in FIG. 3, the distance (pitch) between the adjacent conductive thread rows 2A and 2B is 2.5 mm and 7 mm, and the unit number of windings of the organic fiber thread 22 of the covering thread 20 is 1200 times/m and 600 times/m. In the "Material" column in FIG. 3, "PEs" means polyester, and "Ny" means nylon. The presence or absence of the "Antistatic" column indicates whether or not the knitted fabric is antistatically treated to make it difficult for static electricity to adhere to the surface of the knitted fabric by applying an antistatic agent to the knitted fabric. Note that the antistatic treatment peels off and loses its effect after repeated washing. Therefore, it is optional whether or not to perform the antistatic treatment. The "0 washes" column indicates the measured surface resistance value before washing. Note that the surface resistance value indicates the maximum resistance value obtained by measuring the surface resistance values of "between the right sleeve and the right front body", "between the front body and the back body", and "between the right sleeve and the 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 by the same measurement method as above after 50 and 100 repeated washes according to JIS L 1930 4M method. If the surface resistance value is less than 10 ¹¹ Ω, it can be evaluated that the surface has antistatic performance that does not charge static electricity. However, if the surface resistance value is in the 10 ¹² Ω range, it is evaluated 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 ² Ω, there is a risk of electric shock due to discharge, but unless the fabric is a knitted fabric consisting mostly of conductive fibers, such a surface resistance value will not be reached. 3, when "Yes" is written in "Disconnection" it means that the tungsten yarn exposed between the organic fiber yarns 22 of the covering yarn 20 is partially disconnected, or that the surface of the tungsten yarn is torn into small pieces or turned over to such an extent that the surface resistance value is significantly increased even though the tungsten yarn is not disconnected. The "disconnection" is judged from an electron microscope photograph of the surface of the tungsten yarn exposed between the organic fiber yarns 22 of the covering yarn 20 and the surface resistance value after 100 washes.

From the results of Examples 1 to 6 in Figure 3, when the distance (pitch) between adjacent conductive yarn rows 2A and 2B is set to 2.5 mm to 7 mm and the unit number of windings of the organic fiber yarn 22 of the covering 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 it can be determined that a break has occurred. Therefore, it was confirmed that the necessary antistatic properties and durability can be obtained without increasing the amount of conductive yarn used.

If the pitch is made shorter than 2.5 mm, the antistatic performance will not be higher than necessary, and if the pitch is made longer than 7.0 mm, the surface resistance will become too high and the necessary antistatic performance will not be obtained.

Through experiments, it has been found that a practical antistatic knitted fabric can be obtained by forming one or more conductive thread rows into one conductive thread row, setting the unit winding number to 1100 to 1200 turns/m, and setting the distance (pitch) to 2.5 to 3.0 mm.

Furthermore, if the number of windings per unit is reduced to as few as 200 times per meter, the surface resistance becomes too small, making it easier to get an electric shock from discharge. Furthermore, if the number of windings per unit is set to, for example, 1,300 times per meter, the surface resistance becomes too large even when the pitch is short, making it impossible to obtain the required antistatic performance.

The present invention makes it possible to ensure the surface resistance required for static control without increasing the number of conductive threads more than necessary, and to provide an antistatic knitted fabric that has the necessary durability and static control properties at a low cost.

1 Non-conductive yarn array 2A, 2B Conductive yarn array 10 Non-conductive yarn 20 Covering yarn (conductive yarn)
21 Tungsten thread 22 Organic fiber thread

Claims (8)

1. An antistatic knitted fabric made of non-conductive yarns and conductive yarns,
   The antistatic knitted fabric is a knitted fabric knitted so that a plurality of non-conductive yarn rows made of the non-conductive yarn and one or more conductive yarn rows made of the conductive yarn appear alternately,
   The conductive yarn is a covering yarn formed by wrapping an organic fiber yarn around a tungsten yarn as a core yarn,
   The distance between two adjacent rows of the one or more conductive yarns is 2.3 mm to 7 mm, and the number of unit windings of the organic fiber yarn of the covering yarn is 600 to 1200 times/m.
2. The diameter of the tungsten yarn is 16 μm to 22 μm,
   2. The antistatic knitted fabric according to claim 1, wherein the organic fiber yarn has a fineness of 20 to 100 denier.
3. An antistatic knitted fabric according to claim 1, in which the organic fiber yarn has a hydrophobic organic fiber yarn surface with an antistatic structure.
4. The one or more conductive thread rows are each composed of one conductive thread row,
   The unit winding number is 1100 to 1200 times/m,
   The antistatic knitted fabric according to claim 3, wherein the distance is 2.5 to 3.0 mm.
5. An antistatic knitted fabric according to claim 2, wherein the organic fiber yarn is a hydrophilic organic fiber yarn.
6. An antistatic knitted fabric according to any one of claims 1 to 5, wherein the knitted fabric is circular knitted.
7. An antistatic knitted fabric according to claim 6, in which at least the circular knitting is a half-knit of the conductive yarn rows.
8. An antistatic garment manufactured using the antistatic knitted fabric of claim 7.

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