Conductive composite fiber and pirn-like fiber package

Abstract

To provide a conductive composite fiber suitable for BCF manufacturing, specifically, to provide a conductive composite fiber and a fiber package yarn thereof, which are blended with a conductive fiber that does not break when stretched, has a sufficient conductivity even after stretching and bulk processing, and has an excellent processing property without causing snarl or filament cracking during blending.SOLUTION: There is provided a composite fiber having a conductive layer made of a thermoplastic polymer containing conductive carbon black and a non-conductive layer made of a thermoplastic polymer. The composite fiber satisfies the following items A to C. Item A: a breaking elongation is 200% or more, item B: a value of surface resistivity is 1.5×102 Ω cm or less, and item C: a twist number is 10 turns / m or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a conductive composite fiber, and more particularly to an unstretched conductive composite fiber suitable for mixing conductive yarns during BCF production.

Background Art

[0002] Conventionally, conductive fibers have been widely used for preventing static electricity in carpets and clothing textiles. As the conductive component, carbon black, which has excellent conductivity and is available at low cost, is frequently used. In particular, many conductive fibers suitable for carpet applications have been proposed. For example, in Patent Document 1, an unstretched conductive fiber composed of a conductive polymer layer containing conductive carbon black and a non-conductive layer not containing conductive carbon black is proposed for the purpose of mixing into bulky continuous filaments (BCF). Further, Patent Document 2 provides a conductive fiber having an excellent static elimination effect and static elimination durability by exposing four or more conductive layers on the outer periphery of the fiber cross-section and arranging the conductive layers substantially equally.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a method of incorporating conductive fibers into a carpet, there is a method of mixing conductive fibers containing carbon black during BCF production. The production of BCF usually involves melting a resin, extruding it from a nozzle having a number of holes, continuously stretching it by passing it through a plurality of rollers, further subjecting it to bulking processing with an air jet, and winding it up with a winder. In this process, a conductive yarn is fed out to the yarn extruded from the nozzle before or after stretching, and they are mixed through a guide or the like.

[0005] However, the unstretched conductive fibers of Patent Document 1 have a thick filament fineness and a small number of filaments, and due to being drum-wound, the convergence of the fibers (multifilaments) is weak, and when unwinding the conductive yarn from the fiber package, filament breakage is caused, resulting in production loss problems such as broken processing yarns. Also, when mixing the conductive yarn before stretching, since filament breakage causes tension fluctuations, streaks occur during stretching, and the BCF in which the conductive composite fiber is mixed (hereinafter referred to as conductive yarn-mixed BCF) has conductivity variations and remains uncomfortable because it is partially charged when made into a carpet.

[0006] Also, the conductive yarn of Patent Document 2 generates snarls due to the difference in the orientation degree of the conductive polymer and the non-conductive polymer that occurs during stretching when the conductive yarn is mixed before stretching. Also, similar to Patent Document 1, the convergence is weak, and when unwinding the conductive yarn from the fiber package, tension fluctuations caused by snarls and filament breakage result in streaks during stretching, and the conductive yarn-mixed BCF has conductivity variations and remains uncomfortable because it is partially charged when made into a carpet.

[0007] An object of the present invention is to provide a conductive composite fiber suitable for a process of mixing conductive fibers before stretching during BCF production. More specifically, it is an object to provide a conductive fiber and its fiber package that not only do not break during stretching of the mixed conductive fiber, but also have sufficient conductivity even after stretching and bulking processing, and are excellent in processability without the occurrence of snarls or filament breakage.

Means for Solving the Problems

[0008] The present invention adopts the following configuration to achieve the above problems. (1) In a composite fiber having a conductive layer made of a thermoplastic polymer containing conductive carbon black and a non-conductive layer made of a thermoplastic polymer, a conductive composite fiber satisfying the following A to C. A. The elongation at break is 200% or more B. The surface specific resistance value is 1.5×10 2 Ω·cm or less C. The number of true twists is 10 turns / m or more. (2) The conductive composite fiber according to (1) above, wherein the conductive layer is arranged at one or more positions on the outer periphery of the cross-section of the composite fiber. (3) A yarn-like fiber package made of the conductive composite fiber according to (1) or (2) above.

Effects of the Invention

[0009] According to the present invention, even when mixed spinning, stretching, and bulking processing are performed during BCF production, it has sufficient conductivity, and it is possible to provide a conductive fiber excellent in processability without snarls or filament breakage and a fiber package thereof.

Embodiments for Carrying Out the Invention

[0010] The conductive composite fiber of the present invention is a conductive composite fiber having a non-conductive layer made of a thermoplastic polymer and a conductive layer in which the thermoplastic polymer contains conductive carbon black.

[0011] The elongation at break of the conductive composite fiber of the present invention is 200% or more because it is necessary to mix-spin, stretch, and bulk-process the conductive composite fiber of the present invention during BCF production. When the elongation at break is less than 200%, the general stretching ratio (3 to 4 times) during BCF production cannot be set, or thread breakage frequently occurs during processing. Considering the equipment limit of the winding speed of the spinning machine, the preferable elongation at break is 200 to 400%.

[0012] In order to obtain a range of breaking elongation, it can be obtained by winding as an undrawn yarn at a take-up speed of 400 to 1000 m / min using a known spinning machine. When polyamide fibers are spun in the take-up speed range of 1000 to 1500 m / min due to the progress of orientation crystallization by the humidity of the environment, the fibers swell and yarn layer displacement etc. occur in the take-up package. It is known that the take-up speed range in which stable winding can be achieved is 1000 m / min or less and 1500 m / min or more. By taking up and winding at 1000 m / min or less, an undrawn yarn having a breaking elongation of 200% or more can be obtained. When taking up at 1500 m / min or more, a fiber structure is formed by the spinning draft, and a highly oriented undrawn yarn having a breaking elongation of 60 to 100% can be obtained.

[0013] The surface specific resistance value of the conductive composite fiber of the present invention is 1.5×10 2 (Ω·cm) or less. By setting the surface specific resistance value to 1.5×10 2 (Ω·cm) or less, the desired static elimination effect can be obtained, and it becomes possible to expand to applications where strong static elimination performance is strongly desired, such as carpets and work clothes. Preferably it is 3.0×10 2 (Ω·cm) or less.

[0014] In order to make the surface specific resistance value 1.5×10 2 (Ω·cm) or less, any method such as adjusting the concentration of conductive carbon black contained in the conductive layer or the arrangement of the conductive layer in the fiber cross section may be used. The conductive carbon black is 10 -3 ~10 2Those having a specific electric resistance of [[ID=]] (Ω·cm) are preferred. As is well known, carbon black generally has poor conductivity when the particles are completely dispersed, but when it forms a chain structure called a structure, its conductivity improves and it becomes what is called conductive carbon black. Therefore, when making a polymer conductive with conductive carbon black, it is important to disperse the carbon black without destroying this structure. As for the electrical conduction mechanism of the conductive carbon black-containing composite, conduction by contact of carbon black chains and conduction by the tunnel effect are considered, but the former is considered to be the main one. Therefore, when the carbon black chains are long and present in a high-density polymer, the contact probability is high and the conductivity is high. According to the study results of the present inventors, when the content of conductive carbon black is less than 15% by weight, there is almost no effect. When it reaches 20% by weight, the conductivity improves rapidly, and when it exceeds 40% by weight, it is almost saturated. Also, when it exceeds 40% by weight, the fluidity of the polymer deteriorates. Therefore, the concentration of conductive carbon black is preferably 30 to 40% by weight.

[0015] The conductive composite fiber of the present invention has a number of true twists of 10 turns / m or more. Preferably, it is 10 to 25 turns / m. When the number of true twists is less than 10 turns / m, it causes filament breakage when the conductive composite fiber is unwound from the fiber package and processing yarn breakage occurs.

[0016] In order to make the number of true twists 10 turns / m or more, a method of winding with a spindle while applying twists is preferred. For example, there are a double twister spindle mainly used in a twisting machine, a draw twister spindle mainly used as a drawn yarn, and the like.

[0017] The higher the actual twist number, the less the processing yarn breakage due to filament breakage in the unwinding from the fiber package. On the other hand, when manufacturing the conductive composite fiber, if an attempt is made to obtain a number exceeding 25 turns / m of actual twist with a draw twister spindle, the spindle rotation speed will be significantly increased, resulting in a large equipment load. If the spindle rotation speed cannot be increased, the speed of the supply roller will be extremely reduced, or a doubling twister spindle will be used for after-twisting in another process, resulting in a decrease in productivity. Therefore, it is preferably carried out with a draw twister spindle, and from the viewpoints of both productivity and processability, the upper limit value is 25 turns / m.

[0018] In the conductive composite fiber of the present invention, it is preferable that the conductive layer is arranged at one or more positions on the outer periphery of the fiber cross-section. Preferably, it is 1 to 6 positions. When it is 2 to 6 positions, it is more preferable that they are scattered at equal intervals. By exposing the conductive layer, sufficient conductivity can be maintained even when it is mixed, drawn, and bulked during BCF production. In addition, the conductivity variation of the conductive yarn mixed BCF is suppressed, and stable conductivity can be obtained without partial charging when made into a carpet.

[0019] The higher the degree of exposure of the conductive layer, the lower the surface specific resistance variation and the more stable the conductivity. On the other hand, it is easy to cause peeling of the fiber surface of the conductive layer due to rubbing with a guide or the like. Therefore, as an index of the degree of exposure, the occupancy rate of the conductive layer in the fiber cross-section is preferably 3 to 15%. The occupancy rate of the conductive layer referred to here can be calculated by the perimeter ratio of the fiber cross-section. By setting it within such a range, there is no peeling of the fiber surface of the conductive layer due to rubbing with a guide or the like, and sufficient strength is maintained even when it is mixed and drawn during BCF production, and good processability without yarn breakage can be obtained.

[0020] As an index of the surface resistivity variation, samples at 10 points in the continuous yarn length direction are collected at 10 m intervals, the surface resistivity values are measured, and it can be expressed by CV% calculated as the value obtained by dividing the standard deviation by the average value. For the conductive fiber of the present invention, it is preferable that this CV% is 0.10% or less. More preferably, it is 0.05% or less. By setting it within such a range, the conductivity variation of the conductive yarn mixed BCF can be suppressed, and stable conductivity can be obtained without partial charging when made into a carpet.

[0021] The fineness of the conductive composite fiber of the present invention is not particularly limited and may be arbitrarily determined in balance with the fineness of BCF, but is preferably 15 to 100 dtex, more preferably 20 to 60 dtex. Within this range, the designability, conductivity, yarn manufacturing and processability when made into a carpet are good.

[0022] The number of filaments of the conductive composite fiber of the present invention is not particularly limited, but is preferably 2 to 8 filaments, more preferably 2 to 5 filaments.

[0023] The breaking strength of the conductive composite fiber of the present invention is preferably 0.4 cN / dtex or more, more preferably 0.6 cN / dtex or more. There is no particular upper limit, but considering the balance with the undrawn yarn and the breaking elongation, the upper limit is preferably about 1.5 cN / dtex. Within this range, good yarn manufacturing property and processability can be obtained.

[0024] The fiber package (winding form) of the conductive composite fiber of the present invention is wound around a bobbin and has a tapered end shape (conical shape). The taper angle can be arbitrarily determined in view of handling, transportation efficiency and ease, and the unwindability of feeding the conductive composite fiber from the package when mixing with BCF. Also, by using a conical fiber package, the winding diameter can be reduced compared to a drum-shaped fiber package even with the same winding amount. Therefore, it is easy to prepare the raw yarn in a small space.

[0025] As the thermoplastic resin used for the conductive layer and the non-conductive layer, there is no particular limitation as long as it is a fiber-forming thermoplastic polymer. However, since polymers with poor drawability have poor processability, polyamide or polyester is preferred.

[0026] As the polyamide, any polyamide obtained by repetitive polycondensation of amide bonds may be used, such as nylon 6, nylon 66, nylon 12, nylon 610, etc., and polyamides containing a small amount of a third component may also be used. Further, these may contain a small amount of additives, matting agents, etc.

[0027] As the polyester, polyethylene terephthalate in which 80 mol% or more of the repeating units are ethylene terephthalate, polybutylene terephthalate in which 80 mol% or more of the repeating units are butylene terephthalate, and polytrimethylene terephthalate in which 80 mol% or more of the repeating units are trimethylene terephthalate are preferred. Also, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene 2,6-dicarboxylic acid, phthalic acid, 5-sodium sulfoisophthalic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid may be copolymerized to such an extent that the fiber-forming property inherent in the polyester homopolymer is not impaired. Further, these may contain a small amount of additives, matting agents, etc.

[0028] Also, in the midst of growing attention to environmental issues, using plant-derived biopolymers or recycled polymers in the present invention is also preferable from the viewpoint of reducing the environmental load. The polymers used in the present invention described above can use recycled polymers recycled by any of chemical recycling, material recycling, and thermal recycling. As the conductive carbon black used for the conductive layer, any of furnace black, acetylene black, channel black, ketjen black, etc. may be used, and preferably furnace black with excellent dispersibility.

[0029] The conductive composite fiber of the present invention is produced by a composite spinning machine capable of separately melting a conductive layer component and a non-conductive layer component.

[0030] The separately melted thermoplastic polymers are respectively metered and supplied to a composite spinning die. Here, the thermoplastic polymers merge to form a composite cross-section in which the conductive layer component is exposed at one or more positions on the outer peripheral surface of the fiber cross-section and are discharged from the die discharge holes.

[0031] The melting temperature may be appropriately determined in consideration of the melting point of the thermoplastic polymer. Preferably, the melting temperature is separately melted at a temperature 20°C to 60°C higher than the melting point. The spinning temperature is the same as the melting temperature and may be appropriately determined in consideration of the melting point of the fiber-forming thermoplastic polymer. Here, the spinning temperature refers to the so-called heat preservation temperature (spin block temperature) that keeps the polymer pipe, metering pump, spinning die, etc. warm.

[0032] The discharged yarn is cooled and solidified by a yarn cooling device, then a spinning oil agent is applied by an oiling device, taken up by a godet roller rotating at a constant speed, and the undrawn yarn is once wound up by a bobbin winder. The take-up speed is preferably 400 to 1000 m / min.

[0033] The once-wound undrawn yarn is wound up with a spindle while applying twist by a known drawing machine to obtain a yarn-like fiber package. The winding tension for obtaining stable unwinding properties is preferably 0.3 g / dtex or less.

[0034] Since the actual twist number can be calculated by dividing the spindle rotation speed by the supply roller (DR) setting speed (hereinafter referred to as the feeding speed), in order to obtain the actual twist number within such a range, the physical properties (strength and elongation, specific resistance value), unwinding properties of the package, equipment load (upper limit of spindle rotation speed), production efficiency, etc. should be considered, and the spindle rotation speed and feeding speed can be arbitrarily set.

[0035] The spindle rotation speed is preferably 6000 to 10000 rpm. Within this range, winding can be carried out without affecting the target physical properties (tensile strength and elongation, specific resistance value). By setting the spindle rotation speed at 6000 rpm or more, the tension for winding can be ensured and maintained, and the obtained package has stable unwinding properties. Also, since the burden on the equipment increases as the spindle rotation speed increases, the preferable upper limit is 10000 rpm.

[0036] The delivery speed is preferably 200 to 500 m / min. Within this range, winding can be carried out without affecting the target physical properties (tensile strength and elongation, specific resistance value). By setting the delivery speed at 200 m / min or more, the tension for winding can be ensured and maintained, and the obtained package has stable unwinding properties.

Examples

[0037] Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples. The measurement methods for characteristic values in the examples are as follows.

[0038] A. Fineness The fiber sample was rotated 200 times with a measuring machine having a perimeter frame of 1.125 m to create a loop-shaped cassette, dried in a hot air dryer (105 ± 2°C × 60 minutes), and then the weight of the cassette was measured with a weighing balance, and the total fineness was calculated from the value multiplied by the official moisture regain (4.5% for nylon).

[0039] B. Tensile strength, elongation at break The fiber sample was measured according to JIS L1013 (2021) for tensile strength and elongation rate, and a tensile strength - elongation curve was drawn. As the test conditions, the type of the testing machine was a constant speed elongation type, the grip interval was 20 cm, and the tensile speed was 20 cm / min. Elongation at break = elongation at break (%) Tensile strength = tensile strength at break (cN) / fineness (dtex).

[0040] C. Surface specific resistance value Wind up the fiber sample with a measuring machine having a frame circumference of 1.125 m so that the total fineness is 350 to 400 dtex, cut it at an arbitrary point on the measuring machine, and make a knot so that it does not come undone. Prepare two acrylic plates with dimensions of 240 × 550 × 5 mm, and attach them with a polyester film on the acrylic plates. At this time, adjust the distance between the acrylic plates to be 10 cm. Uniformly apply Doteite (registered trademark) (manufactured by Fujikura Kasei Co., Ltd.) on the upper part of the attached polyester film (thickness 40 to 60 μm) and let it dry naturally for 2 hours or more. Then, cut the prepared sample, attach one side to the upper holder of the measuring box, pass the other side through the lower holder, and hang a 15 g clip. Turn on the switch of a digital ultra-high resistance / microammeter (5450 / 51 manufactured by Edsy Co., Ltd.), apply a voltage of 1000 v, and read the measured value from the current value after 2 minutes. The surface specific resistance value was determined by the following formula. The fineness used in the calculated value was the value obtained by the measuring method in section A above. For example, in the case of a fineness of 60 dtex, wind up 6 times with a measuring machine and perform the measurement with a fiber sample having a total fineness of 360 dtex. RS = R × D / (10 × L × SG) × 10 -5 RS: Specific resistance (Ω·cm) R: Electrical resistance value (Ω) D: Total fineness (dtex) L: Test length (10 cm) SG: Yarn density (nylon 1.14 g / cm 3 )

[0041] D. Variation in surface specific resistance value (CV%) Collect 10 samples at 10 m intervals in the continuous yarn length direction and measure the surface specific resistance values in section C above respectively. Let the average specific resistance value of the 10 surface specific resistance values obtained be P (Ω·cm). Also, after calculating the standard deviation Q of the 10 specific resistance values obtained simultaneously, calculate the variation in surface specific resistance value CV% = Q / P from the ratio of P and Q.

[0042] E. Number of actual twists Suspend the yarn on the measuring instrument, apply a load (cN) of fineness (dtex) × 1 / 30 to the yarn at a yarn length of 1 m, pull it, and unwind the twist. The number of turns when the twist disappears is defined as the actual twist.

[0043] F. Processability The number of stops during the production of conductive yarn blended BCF was used as the evaluation criterion. ◎: Less than 3 times / 1,000,000 m ○: 3 times or more and less than 5 times / 1,000,000 m ×: 5 times or more / 1,000,000 m.

[0044] G. Evaluation of the Conductive Performance of the Carpet A carpet with a basis weight of 480 g / m 2 and a pile height of 3.5 mm, tufted, was cut into a width of 90 cm × 90 cm to obtain a test piece. Human body static electricity evaluation was carried out in a laboratory under the environment of temperature 23°C ± 1°C and relative humidity 25% ± 3% in accordance with JIS L 1021-16 Method B (Stroll method). The test was conducted 3 times on the same test piece. From each test result, excluding the abnormal values above and below, 5 values were sequentially picked from the higher maximum value and 5 values were sequentially picked from the lower maximum value, and the arithmetic mean was obtained, and the evaluation was made based on the average of the 3 measurement values. ◎: Static potential less than 1.0 kV △: Static potential 1.0 kV or more and less than 3.0 kV ×: Static potential 3.0 kV or more.

[0045] H. Occupancy Rate of the Conductive Layer Regarding the circumference of the cross-section of the composite fiber as A and the length of the conductive layer exposed on the outer periphery of the composite fiber as b, each length was measured with a microscope. The occupancy rate is calculated as b / A × 100. For each length, 4 points were arbitrarily sampled in the longitudinal direction of the fiber sample, and for each sampling, 1 filament was arbitrarily measured, and the average value of the 4 data was used.

[0046] [Example 1] A nylon-based chip containing 35% by weight of conductive carbon black as a conductive layer polymer (manufactured by DIC, trade name "CARBOREX NYRON YT-01") and nylon 6 chips as a non-conductive layer polymer were melted at a melting temperature of 275°C using individual pressure meltters at a ratio of 5% by mass of the conductive layer polymer and 95% by mass of the non-conductive layer polymer, merged into a 16-hole composite spinneret, and a composite cross-section was formed with the conductive layer polymer exposed at one location on the outer periphery of the fiber cross-section and extruded from the spinneret holes. The extruded yarn was cooled by a uniflow type cooling device, an emulsion oil agent was applied, wound up at a take-up speed of 800 m / min, and 8 drums were wound with 60 dtex, 2-filament undrawn yarns.

[0047] Subsequently, the once-wound undrawn yarn was supplied to a drawing machine having draw twister spindles and wound onto bobbins while applying twist at a supply roller (DR) set speed of 500 m / min and a spindle rotation speed of 7000 rpm to obtain 60 dtex - 2-filament undrawn conductive composite fibers and a package of tow-like fibers. The conductive layer occupancy in the fiber cross-section of the fibers sampled from the tow-like fiber package was 5%. The results of the raw yarn properties of the obtained undrawn conductive composite fibers are shown in Table 1.

[0048] The obtained undrawn conductive composite fibers and the package of tow-like fibers were set on a creel, and the undrawn conductive composite fibers payed out from the creel were mixed with a 68-filament polyamide 6 yarn extruded from a melt spinning apparatus through a guide, continuously drawn between a first godet roller rotating at 526 m / min at 130°C and a second godet roller rotating at 2000 m / min at 155°C, further bulked by an air jet at 160°C, and then wound up by a winder. The obtained BCF was 1300 dtex / 68f and contained 1 yarn of the drawn conductive composite fiber.

[0049] In addition, a carpet manufactured using two of these conductive yarn blended BCFs per 2.54 cm had an absolute value of less than 1 kV according to the human body charging voltage measurement method, indicating excellent conductivity. The evaluation results are shown in Table 1. The processability of the conductive yarn blended BCF and the conductivity of the carpet were good.

[0050] [Examples 2 - 3, Comparative Example 1] Undrawn conductive composite fibers were obtained under the same conditions as in Example 1 except that the set speed of the supply roller (DR) of the drawing machine was changed as described in Table 1. The evaluation results are shown in Table 1. In Examples 2 - 3, the processability of the conductive yarn blended BCF and the conductivity of the carpet were good. In Comparative Example 1 with a small number of true twists, filament breakage occurred during unwinding from the fiber package, resulting in unstable drawing. Thread breakage occurred 7 times at 1 million m, and the processability was inferior. Also, when made into a carpet, it was partially charged.

[0051] [Comparative Example 2] Conductive yarn blended BCF and a carpet were obtained under the same conditions as in Example 1 except that the undrawn conductive composite fibers once wound in Example 1 and the drum - shaped fiber package were set on the creel. The evaluation results are shown in Table 1. Since the drum - shaped fiber package was not twisted, filament breakage occurred during unwinding from the fiber package, resulting in unstable drawing, and the processability was inferior. Also, when made into a carpet, it was partially charged.

[0052] [Example 4] Undrawn conductive composite fibers were obtained under the same conditions as in Example 1 except that the conductive layer polymer was exposed on the fiber surface at 6 locations. The evaluation results are shown in Table 1.

[0053] [Comparative Example 3] Undrawn conductive composite fibers were obtained under the same conditions as in Example 1 except that a core - sheath composite form was used in which the conductive layer polymer was not exposed on the fiber surface. The evaluation results are shown in Table 1.

[0054] [Examples 5 - 6] An undrawn conductive composite fiber was obtained under the same conditions as in Example 1 except that the drawing speed was changed as described in Table 1. The evaluation results are shown in Table 1.

[0055] [Comparative Example 4] A highly oriented undrawn conductive composite fiber was obtained under the same conditions as in Example 1 except that the drawing speed was changed as described in Table 1. The evaluation results are shown in Table 1.

[0056]

Table 1

[0057] [Example 7, Comparative Examples 5 - 6] An undrawn conductive composite fiber was obtained under the same conditions as in Example 1 except that the mass ratio of the conductive layer polymer and the non - conductive layer polymer and the carbon black concentration were changed as described in Table 2. The evaluation results are shown in Table 2. In Comparative Example 5 where the carbon black content in the conductive layer polymer was 10% by mass and Comparative Example 6 where the mass ratio of the conductive layer polymer was 3%, the surface resistivity was high and the conductivity was inferior.

[0058] [Example 8] An undrawn conductive composite fiber was obtained under the same conditions as in Example 1 except that a material - recycled nylon 6 chip obtained by remelting fiber scraps was used as the non - conductive layer polymer. The evaluation results are shown in Table 2.

[0059] [Example 9] An undrawn conductive composite fiber was obtained under the same conditions as in Example 1 except that a nylon 610 chip with a bio - base carbon concentration of 63% derived from biomass - derived sebacic acid was used as the non - conductive layer polymer. The evaluation results are shown in Table 2.

[0060]

Table 2

Claims

1. In a composite fiber having a conductive layer made of a thermoplastic polymer containing conductive carbon black and a non-conductive layer made of a thermoplastic polymer, a conductive composite fiber satisfying the following A to C. A. Elongation at break is 200% or more B. Surface resistivity value is 1.5×10 ２ Ω·cm or less C. Number of true twists is 10 turns / m or more

2. The conductive composite fiber according to claim 1, wherein the conductive layer is arranged at one or more positions on the outer periphery of the cross section of the composite fiber.

3. A hank-like fiber package made of the conductive composite fiber according to claim 1 or 2.

Images