JP6805424B2 - Method of manufacturing conductive yarn - Google Patents

Description

The present invention relates to a conductive yarn made of a multifilament in which the periphery of a fiber material which is a dielectric is coated with a metal material, and a method for producing the same.

Conventionally, metal electric wires have been used for communication and power supply, but copper wires are mainly used as metal electric wires. An electric wire using a copper wire is vulnerable to deformation such as bending and twisting, and when it is wired to a movable part such as an electric device, the deformation is repeatedly applied, so that there is a problem that the wire is easily broken.

To solve these problems of electric wires, a conductive yarn in which a metal such as copper is plated on the surface of a fiber material made of synthetic resin having excellent durability against bending and twisting has been proposed. For example, in Patent Document 1, a metal plating treatment is applied around a high-strength organic synthetic fiber having a tensile strength of 7 cN / dtex or more, and a metal plating layer is formed in a range where the number of twists T (times / m) is 50 ≦ T ≦ 150. A conductor obtained by twisting filament bundles of formed high-strength organic synthetic fibers is described. Further, in Patent Document 2, a fiber bundle is introduced from a passage port provided in the plating treatment tank, and the fiber bundle is immersed in the plating solution in a state where the plating solution in the plating treatment tank overflows from the passage port, and further plating is performed. The passage path of the fiber bundle in the treatment tank is in a plane substantially parallel to the plating liquid surface, and by performing the plating treatment while keeping the tension applied to the fiber bundle constant, the fiber bundle composed of a plurality of filaments is continuously plated. A plating treatment method in which each filament is uniformly coated with a plating metal is described. Further, in Patent Document 3, it is an insulated wire containing an organic fiber yarn, and the organic fiber yarn is metal-coated, and the metal-coated organic fiber yarn is further coated with a thermoplastic resin. The thermal decomposition temperature of the strip is 400 ° C. or higher, the tensile strength is 15 cN / dtex or higher, and the electric resistance value of the metal-coated organic fiber yarn is 3 Ω / m or lower, which is measured based on JIS C 3216-6. Insulated wires having a softening resistance temperature of 170 ° C. or higher are described.

Japanese Unexamined Patent Publication No. 2011-76852 Japanese Unexamined Patent Publication No. 2011-153365 Japanese Unexamined Patent Publication No. 2014-86390

In the above-mentioned patent document, it is possible to obtain an electric wire having light weight, flexibility, high tensile strength and high conductivity by using an insulating fiber material, and bending and twisting as compared with a conventional electric wire using a copper wire. It is possible to improve the durability against deformation such as.

Taking advantage of this characteristic, while product development in the field of fusion of electrical equipment and clothing such as wearable electronics is progressing, this kind of conductive thread is not only used as a signal line, but also as a power supply line or signal line for wireless communication, etc. There is an increasing demand for high frequency electrical characteristics including antennas. In that case, in addition to being lightweight and flexible for weaving and knitting into a woven or knitted fabric in the same manner as ordinary yarn, the characteristics of low transmission loss at high frequencies are required.

Therefore, an object of the present invention is to provide a conductive yarn having flexibility and conductivity, low high frequency transmission loss, and bending durability, and a method for producing the same.

The conductive yarn according to the present invention is a conductive yarn made of a multifilament in which a fiber material having a fineness of 10 decitex or less and being a dielectric is coated with a metal material, and a metal material is formed around each fiber material of the multifilament. Is adhered in a uniform layer, the high-frequency transmission loss at 300 MHz to 1500 MHz is 5 dB or less, and the electrical resistance maintains conductivity at an increase rate of 150% or less for 70,000 or more dynamic drive tests. It has bending durability. Further, the multifilament has a basis weight of 0.1 g / m to 1 g / m, an electric resistance of 0.5 Ω / m to 10 Ω / m, and a bending rigidity of 0.04 gf · cm required by KESFB2-AUTO-A. ² / yarn ~ 5gf · cm ² / yarn. Further, the multifilament has a twist number of 160 times / m or more when the fineness is less than 500 decitex, a twist number of 100 times / m or more when the fineness is 500 decitex to 1200 decitex, and a twist number when the fineness is 1200 decitex to 2000 decitex. It is set to 50 times / m or more.

The method for producing a conductive yarn according to the present invention is a tension (tension T) applied in the yarn length direction to a fiber bundle (fineness D decitex) in which a fiber material having a fineness of 10 decitex or less and being a dielectric is focused in a non-twisted state. Newton) was immersed in the plating solution with T ≦ D / 300, and the fiber bundle immersed in the plating solution was subjected to vibration of 60 Hz or less to disperse the fiber material and then plated. By performing the above, the periphery of the fiber material is coated with the metal material, and the multifilament in which the fiber material whose periphery is coated with the metal material is focused is produced. Further, the multifilament is produced by twisting.

The present invention has a multifilament in which a fiber material having a fineness of 10 decitex or less and a dielectric material is coated with a metal material, and has a high frequency transmission loss of 5 dB or less at 300 MHz to 1500 MHz and a dynamic of 70,000 times or more. Since the electrical resistance is maintained at an increase rate of 150% or less with respect to the drive test, it has excellent characteristics such as low high frequency transmission loss and bending durability as well as flexibility and conductivity.

It is explanatory drawing which shows the apparatus structure which performs the bending durability test. It is a table which shows each characteristic of a conductive yarn. It is a graph which shows the relationship between the frequency of a conductive yarn, and high frequency transmission loss. It is a graph which shows the relationship between the number of twists of a conductive yarn, and specific resistance. It is a table which shows the result of the bending durability test of a conductive yarn.

Hereinafter, embodiments according to the present invention will be described in detail. The conductive yarn according to the present invention is made of a multifilament in which a fiber material having a fineness of 10 decitex or less and being a dielectric is coated with a metal material. Since the metal material is coated around each fiber material constituting the multifilament, the metal material is distributed almost uniformly over the entire multifilament. Therefore, as will be described later, it has come to have excellent electrical characteristics such as reduction of electric resistance and high frequency transmission loss, and it has been possible to realize weight reduction, excellent flexibility and bending durability.

Examples of the fiber material as a dielectric include polyester, nylon, acrylic, polypropylene, para-aramid, meta-aramid, polyarylate, polybenzoimidazole and the like as synthetic fiber materials, and glass as an inorganic fiber material. .. Then, these fiber materials may be mixed. The fineness of the fiber material is preferably 10 decitex or less, more preferably 1 decitex to 10 decitex. If the fineness is greater than 10 decitex, the electrical resistance cannot be sufficiently reduced when a metal material is attached.

The metal material may be any metal such as copper, copper / nickel, nickel, gold, palladium, and silver that can be precipitated by known electroless plating treatment, and these metals may be formed alone or in combination. Is also possible and is not particularly limited.

The conductive yarn uses a fiber material such as a synthetic fiber material that is lighter than the metal material, and the metal material adheres around each fiber material constituting the multifilament, so that sufficient conductivity is ensured. It is possible to reduce the weight. Specifically, the electrical resistance of the multifilament can be set to 0.5Ω / m to 10Ω / m, and the basis weight of the multifilament can be set to 0.1 g / m to 1 g / m. By setting the electrical resistance to 0.5Ω / m to 10Ω / m, it is possible to secure the same level of conductivity as a conventional electric wire. Further, when the electric resistance becomes larger than 10 Ω / m, the current decrease due to the electric resistance becomes large in the wiring of 1 m or more when it is used for power supply, and for example, when it is used for LED power supply, the decrease in the amount of light is clearly recognized. Will be done.

Regarding the basis weight, if the basis weight is smaller than 0.1 g / m, the amount of metal material adhered becomes insufficient and it becomes difficult to secure sufficient conductivity, and if the basis weight is larger than 1 g / m, the weight is sufficiently light. It becomes difficult to achieve the conversion. The amount of the metal material adhered is preferably 0.4 g / m or less from the viewpoint of weight reduction and conductivity.

The conductive thread is composed of a multifilament in which a metal material is coated around a fiber material which is a dielectric and the fiber material coated with the metal material is focused, so that high frequency transmission loss can be suppressed low and wireless. It is suitable for applications such as communication and signal transmission. Specifically, the high frequency transmission loss in 300 MHz to 1500 MHz can be suppressed to 5 dB or less, and it has a sufficient function as a material for an antenna for wireless communication.

As for the high frequency characteristics, the smaller the variation in the electrical resistance in the fiber length direction (high frequency propagation direction) of the fiber material, the smaller the high frequency transmission loss. Further, since high-frequency radio waves mainly propagate on the surface of the conductive thread, the larger the surface area (the larger the number of filaments), the smaller the high-frequency transmission loss. Further, since the electric resistance in the yarn length direction is stabilized by adding a twist to the conductive yarn, the higher the number of twists, the lower the high frequency transmission loss even if the electric resistance is the same. In the present invention, since it is possible to obtain a conductive yarn made of a multifilament having a large surface area with little variation in electrical resistance in the yarn length direction, it is possible to obtain a high frequency transmission loss as low as that of a conventional conductive wire such as a copper wire. It will be possible.

Further, as described later, since the conductive yarn is uniformly coated with the metal material around each fiber material by the plating treatment, the multifilament is formed even when the metal material is thinly adhered around each fiber material. As a whole, the amount of adhesion can be sufficient to ensure conductivity. Then, by adhering the metal material to a thin and uniform layer around each fiber material, it is possible to suppress the breakage of the metal layer due to the deformation of the fiber material while maintaining the flexibility of each fiber material. Therefore, the flexibility of the multifilament can be ensured, and the bending durability can be improved. Since the metal material is uniformly adhered around the fiber material, there is almost no anisotropy in the flexibility and bending durability of the multifilament, and it is curved and deformed in any direction like a normal thread. It is possible to withstand the same weaving process and knitting process as before.

Regarding the flexibility of the conductive yarn, it is preferable to set the flexural rigidity required by KESFB2-AUTO-A to 0.04 gf · cm ² / yarn to 5 gf · cm ² / yarn. When the flexural rigidity is lower than 0.04 gf · cm ² / yarn, the amount of metal material adhering to the fiber material is small and it becomes difficult to realize an electrical resistance of 10 Ω / m or less, and 5 gf · cm ² / yarn. If it is higher than, the flexibility is reduced and defects occur in the weaving process and the knitting process.

KESFB2-AUTO-A is an automated pure bending tester manufactured by Kato Tech Co., Ltd., which measures the bending moment by changing the curvature under the conditions of a clamp interval of 10 mm and a bending deformation speed of 0.5 cm ^-1 / s. It is a device. As one of the methods for evaluating the flexibility of a yarn, the flexural rigidity (gf · cm ² / yarn) of one yarn can be obtained from an arbitrary measurement curvature range based on the measured bending moment and the number of yarns.

The bending durability of the conductive yarn can be examined by performing a durability test to see how much the conductivity is maintained by the dynamic drive test in which the conductive yarn is repeatedly bent and deformed so as to be bent. Considering the number of bending deformations that the conductive yarn receives in the manufacturing process such as weaving treatment or knitting treatment and the number of bending deformations that it receives while it is being used as a product, conductivity is ensured with the number of bending deformations of 70,000 or more. It is enough if it is. In the conductive yarn according to the present invention, the electrical resistance is maintained at an increase rate of 150% or less even after performing a dynamic drive test of 70,000 times or more, and excellent bending durability is maintained. I have.

By twisting the conductive yarn, the electrical characteristics can be stabilized, and it becomes possible to obtain a conductive yarn having uniform electrical characteristics. By adding twisting, the fiber materials coated with the metal material are brought into close contact with each other, and the metal materials are in a stable electrical connection state in the entire multifilament, and the electrical characteristics are stabilized.

Specifically, when the fineness is less than 500 decitex, the number of twists is preferably set to 160 times / m or more, and when the fineness is 500 decitex to 1200 decitex, the number of twists is preferably set to 100 times / m or more. However, in 1200 decitex to 2000 decitex, it is preferable to set the number of twists to 50 times / m or more. In the case of a thin conductive yarn having a fineness of less than 500 decitex, if the number of twists is less than 160 times / m, the electric resistance of the conductive yarn will vary. Similarly, in the case of a thick conductive yarn having a fineness of 500 decitex to 1200 decitex, if the number of twists is less than 100 times / m, the electrical resistance varies, and the fineness of the conductive yarn having a fineness of 1200 decitex to 2000 decitex becomes larger. In that case, if the number of twists is less than 50 times / m, the electric resistance will vary.

In the case of producing a conductive yarn, each step is performed on a fiber bundle made of long fibers and having a fineness of 10 decitex or less, which is bundled in a non-twisted state. Since the fiber bundle is in a non-twisted state, when it is immersed in each treatment tank, the fiber material made of long fibers becomes loose, and the surface of each fiber material can be uniformly treated.

In the pretreatment step, the fiber bundle is first refined, and then a catalyst is applied to the fiber material and a catalyst is activated. The catalyst addition treatment is a treatment for fixing the catalyst on the surface of the fiber material in order to perform the electroless plating treatment, and examples of the catalyst include known metal materials such as tin silver, tin palladium, and palladium. In the catalyst activation treatment, a treatment such as acid immersion is performed to activate the catalyst.

In the electroless plating process, the tension (tension T Newton) applied in the thread length direction to the fiber bundle (fineness D decitex) processed in the pretreatment process is set to D / 1000 ≦ T ≦ D / 300. The plating process is performed by sequentially immersing in a plurality of electroless plating tanks while running in the set low tension state. By applying vibration of 60 Hz or less to the fiber bundle while the fiber bundle is immersed in the electroless plating tank, the fiber material of the fiber bundle that is in a focused state during traveling vibrates in a loosened state in the plating solution. become. The plating solution can penetrate between the fiber materials that vibrate in a loosened state, and the periphery of each fiber material can be uniformly plated to adhere the metal material.

The method of applying vibration to the fiber bundle may be such that the fiber material vibrates in a separated state, and is not particularly limited. For example, the traveling roller that travels the fiber bundle is vibrated in a direction intersecting the traveling direction to vibrate the fiber material. Can be separated. Further, the vibrating roller may be intermittently brought into contact with the fiber bundle traveling in the plating tank, or the plating solution may be made to flow to vibrate. The frequency to be applied is preferably 60 Hz or less, more preferably 28 Hz to 60 Hz.

The electroless plating process can be performed using a known processing method. For example, a commercially available plating solution is used as the plating solution, the temperature of the plating bath is set to 25 ° C to 50 ° C, and the processing time is set. It may be done for 10 to 20 minutes.

The metal plating layer formed by the electroless plating treatment may be any metal such as copper, copper / nickel, nickel, gold, palladium, and silver that can be precipitated by the known electroless plating treatment. It can be formed as one or a combination, and is not particularly limited. By uniformly adhering the catalyst to the periphery of each fiber material, the periphery of each fiber material can be coated with a uniform metal plating layer by electroless plating.

In the electroplating process, the tension (tension T Newton) applied in the thread length direction to the fiber bundle (fineness D decitex) processed in the electroless plating process is set to D / 1000 ≦ T ≦ D / 300. The plating process is performed by sequentially immersing in a plurality of electroplating tanks while running in the low tension state set in. In the state where the fiber bundle is immersed in the electroplating tank, by applying vibration of 60 Hz or less to the fiber bundle as in the electroless plating process, the fiber material of the fiber bundle vibrates in a loosened state in the plating solution. Will come to do. The plating solution penetrates between the fiber materials that vibrate in a loose state, and the metal plating layer formed by electroless plating around each fiber material is uniformly plated to increase the thickness of the metal plating layer. It can be made evenly thick. Therefore, the amount of the metal material adhering to the periphery of the fiber material can be set to a desired amount by the electroplating treatment, and the metal plating layer with less unevenness can be formed.

The electroplating process can be performed by a known processing method. For example, a commercially available copper sulfate solution formulation (standard formulation manufactured by Okuno Pharmaceutical Co., Ltd.) is used as the plating solution, and the temperature of the plating bath is set to 20 ° C. to The temperature may be set to 50 ° C. and the processing time may be 10 to 20 minutes.

As described above, the multifilament in which the periphery of each fiber material is coated with a metal material by performing electroless plating treatment and electroplating treatment on the fiber bundle in which the long fiber fiber material as a raw material is bundled in a non-twisted state. However, such a treatment is performed in a state where the fiber bundle is subjected to low tension. In a state where the tension (tension T Newton) applied to the fiber bundle (fineness D decitex) in the yarn length direction is set to T ≦ D / 300, preferably D / 1000 ≦ T ≦ D / 500. By applying vibration of 60 Hz or less to perform plating treatment in a state where tension is applied, a conductive yarn that is durable against deformation such as expansion and contraction and bending can be obtained. For example, in the case of a fiber bundle having a fineness of 1000 decitex, the treatment may be performed in a state where a low tension of 3 Newton or less is applied.

Hereinafter, the present invention will be specifically described with reference to examples of the present invention, but the present invention is not limited to the following examples. The measurement methods and tests used in the examples are as follows.

<Weight measurement>
The weight per unit length of the fiber material and the conductive yarn as raw materials was measured using an electronic balance (manufactured by METTLER TOLEDO Co., Ltd .; AB54-S).

<Measurement of electrical resistance>
It was measured by the 4-terminal method using a digital multimeter (ADC Co., Ltd .; R6552). At the time of measurement, the conductive yarn was set so as to have a predetermined length in a state where tension was applied to the conductive yarn with a predetermined load.

<Flexural rigidity measurement>
Using an automated pure bending tester (Kato Tech Co., Ltd .; KESFB2-AUTO-A), bend moments of 1 to 5 thread samples under the conditions of a clamping interval of 10 mm and a bending deformation speed of 0.5 cm ^-1 / s. Was measured, and the flexural rigidity was calculated in the range of curvature 0.5 to 1.5 based on the measured bending moment.

<Measurement of high frequency characteristics>
After insulatingly coating the conductive thread under test with a heat-shrinkable tube (Versafit V4-0.8-0-SP-SM), the two are brought into close contact with each other in parallel to form a parallel two-wire transmission line, and a 4-port network analyzer. The transmission loss in differential transmission was obtained by acquiring the mixed mode S parameter using (Agile Technology Co., Ltd.) and a GSSG probe (Cascade Microtech Co., Ltd.).

<Bending durability test>
As shown in FIG. 1, a conductive thread C having a length of 500 mm is inserted from above between a pair of bending bars B arranged horizontally in parallel with an interval of 1 mm, and a weight W of 20 g is attached to the lower end to attach a weight W to the upper end. The side is attached to the grip body A. The cross-sectional shape of the bending bar B is formed in a circle having a diameter of 10 mm, and the radius of curvature of the outer peripheral surface is set to 5 mm. Then, the grip body A is reciprocally swung in a direction orthogonal to the bending bar B, and the conductive thread C is bent to 135 degrees on both sides around the position sandwiched by the bending bar B. The operating speed of the grip body A was about 60 times / minute. Due to the operation of the grip body A, the portion of the conductive thread C sandwiched between the bending bars B is repeatedly bent and deformed. Then, the electric resistance was measured at a place including the bending deformation portion every predetermined number of times of bending.

[Example 1]
As a raw material, a fiber bundle made of para-aramid fiber (manufactured by Teijin Limited; Technora) was used. Three types of fineness were prepared: 440 decitex, 1100 decitex and 1670 decitex. As the fiber bundle used as a raw material, a plurality of long fibers were aligned in the fiber length direction and bundled in a non-twisted state.

<Manufacturing of conductive yarn>
First, in the pretreatment step, a palladium chloride colloidal solution (standard formulation manufactured by Okuno Pharmaceutical Co., Ltd.) is used as a catalyst, and a catalyst is applied to the surface of the long fibers constituting the fiber bundle by an immersion method, and a commercially available sulfuric acid solution (commercially available sulfuric acid solution). The catalyst was activated by acid immersion using (standard formulation manufactured by Seiwa Chemical Co., Ltd.).

Next, electroless plating was performed on the fiber bundle in which the catalyst attached to the periphery of the long fibers was activated by the pretreatment. In the electroless plating treatment, a copper sulfate solution formulation (standard formulation manufactured by Okuno Pharmaceutical Co., Ltd.) was used as the plating solution, and a plurality of plating baths containing the plating solution were arranged in the fiber bundle transport direction. Then, while the tension (tension T Newton) applied to the fiber bundle (D decitex) in the thread length direction is set to T = D / 500 and conveyed, the solution temperature is 40 ° C. and the processing time is 15 minutes. The electroless plating process was performed by passing through the plating bath and immersing it. By applying vibration while the fiber bundle was immersed, the long fibers constituting the fiber bundle were scattered and the periphery thereof was evenly electroless plated.

Next, the electroless-plated fiber bundle was electroplated. In the electroplating treatment, a copper sulfate solution formulation (standard formulation manufactured by Okuno Pharmaceutical Co., Ltd.) was used as the plating solution, and a plurality of plating baths containing the plating solution were arranged in the fiber bundle transport direction. Then, while the tension (tension T Newton) applied to the fiber bundle (D decitex) in the thread length direction is set to T = D / 500 and conveyed, the solution temperature is 20 ° C. and the processing time is 15 minutes. Electroplating was performed by passing through the plating bath and immersing it. By applying vibration while the fiber bundle was immersed, the long fibers constituting the fiber bundle were scattered and the periphery thereof was evenly electroplated.

Through the above treatment, a conductive yarn made of a multifilament in which the circumference of long fibers is coated with copper was produced.

<Twisted conductive yarn>
Some of the produced conductive yarns were twisted with a predetermined number of twists under a load of 20 g by a twisting machine (manufactured by SANKIN ENGINIEERING CO., LTD.). A conductive yarn of 440 decitex with 200 twists / m and 160 twists / m was prepared and used as Example 1-1 and Example 1-2, and the conductive yarn of 1100 decitex was twisted 30 times / m. The twisted m was evaluated as Example 1-3. The 1670 decitex conductive yarn was evaluated as it was in Example 1-4 without twisting.

<Measurement of each characteristic of conductive yarn>
The produced conductive yarn was cut to a predetermined length, the weight and electric resistance were measured, the weight and electric resistance per unit length were calculated, and the flexural rigidity of the conductive yarn of the predetermined length was measured. The measurement results are shown in FIG. Further, FIG. 3 is a graph showing the measurement results of high frequency transmission loss at frequencies of 300 MHz to 1500 MHz. In the graph, the horizontal axis represents frequency (MHz) and the vertical axis represents high frequency transmission loss (dB).

[Example 2]
As a raw material, a fiber bundle made of polyethylene terephthalate (PET) (manufactured by Teijin Limited; 1100 decitex / 192f) was used. As the fiber bundle used as a raw material, a plurality of long fibers were aligned in the fiber length direction and bundled in a non-twisted state.

<Manufacturing of conductive yarn>
In the same manner as in Example 1, a conductive yarn was produced by performing a pretreatment step, an electroless plating treatment step, and an electroplating treatment step on the fiber bundle as a raw material. The obtained conductive yarn was evaluated as it was in Example 2 without twisting.

<Measurement of each characteristic of conductive yarn>
The produced conductive yarn was cut to a predetermined length, and measurement was carried out in the same manner as in Example 1. The measurement results are shown in FIGS. 2 and 3.

[Comparative Example 1]
As a comparative example, from a copper wire made of a single wire (Kyowa Harmonet Co., Ltd .; 2UEW, diameter 0.2 mm) and an insulating coated copper wire (manufactured by Onamba Co., Ltd .; insulating coating material, diameter 0.18 mm x 20). The number of twisted wires taken out was 2, 12, and 20 in 3 types, and 12 and 20 were twisted at 26 times / m. The copper wire made of a single wire was designated as Comparative Example 1-1, and the bundles of 2, 12, and 20 copper wires were designated as Comparative Examples 1-2 to 1-4, respectively.

<Measurement of each characteristic of copper wire and copper wire bundle>
Comparative Examples 1-1 to 1-4 were cut to a predetermined length and measured in the same manner as in Example 1. The measurement results are shown in FIG. Further, FIG. 3 shows a graph relating to the high frequency transmission loss measured for Comparative Examples 1-1 to 1-3.

<About characteristic evaluation of conductive yarn>
The conductive thread has a weight similar to that of a copper wire made of a single wire (diameter 0.2 mm) of Comparative Example 1-1 and has a low resistance of 5 Ω / m or less, and is used for communication and power supply while being lightweight. It can be seen that it has the required conductivity.

In terms of flexural rigidity, it can be seen that Examples 1-1 to 1-4 have flexibility in the range of 0.04 gf · cm ² / yarn to 5 gf · cm ² / yarn. On the other hand, in the copper wire bundle made of the stranded wires of Comparative Examples 1-3 and 1-4, the bending rigidity cannot be accurately measured, and the measurable copper wire of Comparative Example 1-1 and the comparative example The copper wire bundle of 1-2 is also larger than the flexural rigidity of the conductive thread, and it can be seen that the conductive thread has much more flexibility than the copper wire.

In the high frequency transmission loss, in Examples 1-1 to 1-4 and Example 2, the frequency is as low as that of Comparative Examples 1-1 to 1-3 in the range of 300 MHz to 1500 MHz. Also has a low loss of 5 dB or less. Further, in relation to the number of twists, comparing Examples 1-1 and 1-2, the high frequency transmission loss is lower in Example 1-1 having a larger number of twists. As will be described later, as the number of twists increases, the electrical resistance decreases and becomes stable, so that it is possible to realize a high-frequency transmission loss comparable to that of the copper wire shown in the comparative example.

As described above, it is confirmed that the conductive yarn has well-balanced characteristics in terms of each characteristic such as weight reduction, conductivity, flexural rigidity and high frequency transmission loss, and is a suitable material for communication and power supply. Was done.

[Example 3]
As a raw material, three types of fiber bundles (manufactured by Teijin Limited; Technora, 440 decitex, 1100 decitex and 1670 decitex) made of paraaramide fibers similar to those in Example 1 were used to measure the change in electrical resistance value depending on the number of twists. As the fiber bundle used as a raw material, a plurality of long fibers were aligned in the fiber length direction and bundled in a non-twisted state.

<Manufacturing of conductive yarn>
In the same manner as in Example 1, a conductive yarn was produced by performing a pretreatment step, an electroless plating treatment step, and an electroplating treatment step on the fiber bundle as a raw material.

<Measurement of twisted yarn and electrical resistance of conductive yarn>
The produced conductive yarn was twisted using the same twisting machine as in Example 1, and the electric resistance was measured for each predetermined number of twists. In the measurement of the electric resistance, the conductive yarn of 440 decitex was set to have a length of 500 mm under a load of 20 g and measured at intervals of 10 cm, and the electric resistance per unit length was calculated. For 1100 decitex and 1670 decitex conductive threads, the length was set to 500 mm under a load of 40 g and measured at intervals of 10 cm, and the electrical resistance per unit length (Ω / m). Was calculated. Then, the average value of the measurement results at the three points was taken as the electric resistance value.

Using the obtained electrical resistance value, the specific resistance with the electrical resistance value when the number of twists was 0 was calculated. FIG. 4 is a graph showing the transition of specific resistance depending on the number of twists. In the graph, the resistivity is on the vertical axis and the number of twists (times / m) is on the horizontal axis.

<Relationship between the number of twists of conductive yarn and electrical resistance>
The 440 decitex conductive yarn shows stable characteristics when the number of twists is 160 times / m or more and the electrical resistance is reduced, and the 1100 decitex conductive yarn shows the electrical resistance when the number of twists is 100 times / m or more. It shows stable characteristics in a lowered state, and the 1670 decitex conductive yarn shows stable characteristics in a state where the number of twists is 50 times / m or more and the electrical resistance is lowered. In either case, by imparting a twist to the conductive yarn, the surface area where the long fibers constituting the conductive yarn are in close contact with each other increases, so that the copper covering the periphery of the long fibers is electrically connected to each other. , It is considered that stable characteristics will be exhibited as the electrical resistance decreases.

[Example 4]
A bending durability test was conducted using a fiber bundle (manufactured by Teijin Limited; Technora, 440 decitex) made of paraaramide fibers similar to that in Example 1 as a raw material. As the fiber bundle used as a raw material, a plurality of long fibers were aligned in the fiber length direction and bundled in a non-twisted state.

<Manufacturing of conductive yarn>
In the same manner as in Example 1, a conductive yarn was produced by performing a pretreatment step, an electroless plating treatment step, and an electroplating treatment step on the fiber bundle as a raw material.

<Twisted conductive yarn>
Using the same twisting machine as in Example 1, the produced conductive yarns were twisted to 161 times / m, 202 times / m, and 300 times / m, respectively, to prepare three types of conductive yarns. Each was designated as Example 4-1 to Example 4-3.

<Bending durability test of conductive yarn and measurement of electrical resistance>
A bending durability test was performed on the prepared conductive yarn, and the electric resistance was measured every predetermined number of times of bending. In the measurement of the electric resistance, the electric resistance per unit length was calculated by setting the length to be 500 mm with a load of 20 g and applying tension and measuring at intervals of 10 cm. The calculation result is shown in FIG.

[Comparative Example 2]
Using the same copper wire as in Comparative Example 1-1 and the same copper wire bundle as in Comparative Example 1-2 as Comparative Example 2-1 and Comparative Example 2-2, the same bending durability test as in Example 4 was performed. , The electrical resistance was measured every predetermined number of bends. The electrical resistance was measured in the same manner as in Example 4. The calculation result is shown in FIG.

<Bending durability of conductive yarn>
With conductive yarn, conductivity is ensured without breaking even after bending 70,000 times or more, and the rate of increase in electrical resistance is suppressed to 150% or less. Therefore, weaving or weaving using conductive yarn. It is possible to knit, and it is considered that it can withstand bending after it becomes a product such as an electric wire. On the other hand, in the case of a copper wire or a copper wire bundle, it was broken up to 8,000 times, and it was confirmed that the conductive yarn according to the present invention has significantly higher bending durability than the copper wire.

The conductive yarn according to the present invention is not only wiring for power supplies and signals incorporated in various wearable members, but also electronics used integrally with multifunctional textiles in an IoT society in which all products and equipment are connected by a communication network. It has sufficient performance as wiring for members. Specifically, it starts with sports-related fields centered on clothing, nursing-care / medical-related fields, safety-safety-related fields such as crime prevention / disaster prevention, interior-related fields such as curtains, wall materials, and sheet materials, and movement of automobiles, etc. It can be applied in a wide range of fields such as fields related to the body and fields related to large structures such as civil engineering and architecture, and is an indispensable element.

Furthermore, industrial machines are required to have flexible electrical wiring and antenna materials that can be used not only as members such as wiring but also as shielding materials and antenna members for wiring by taking advantage of their electrical characteristics corresponding to high frequencies. It is expected that it will be developed for various purposes such as mobile devices such as large electronic devices and electric vehicles.

A ... grip body, B ... bending bar, C ... conductive thread, W ... weight

Claims (2)

The tension (tension T Newton) applied in the yarn length direction to the fiber bundle (fineness D decitex) obtained by bundling fiber materials having a fineness of 10 decitex or less and being a dielectric in a non-twisted state is T ≦ D / 300. By immersing the fiber bundle in the plating solution in the state set to the above, applying vibration of 60 Hz or less to the fiber bundle immersed in the plating solution, and performing the plating treatment in a state where the fiber material is separated, the periphery of the fiber material is made of metal. A method for producing a conductive yarn, which comprises a multifilament in which the fibrous material is coated with a material and the periphery is coated with a metal material. The method for producing a conductive yarn according to claim 1, wherein the multifilament is produced by twisting.

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