Wear-resistant aramid fiber multilayer composite conductive covering yarn and preparation method thereof

Abstract

The invention discloses a wear-resistant aramid fiber multi-layer composite conductive covering yarn and a preparation method thereof, and the preparation method adopts a production process for manufacturing an aramid fiber conductive composite yarn by combining electrostatic spinning and friction spinning, and adopts a blending manufacturing method for manufacturing a nano conductive fiber mixed aramid fiber network through electrostatic spinning. The method enables a conductive material and an aramid matrix to be densely arranged and tightly combined, and comprises the following steps: S1, mixing a conductive material dispersion liquid with a spinning solution, filling a spinning solution supply table, preparing a micro-nano conductive fiber network in an electrostatic spinning manner, and blending the micro-nano conductive fiber network with aramid short fiber strands drafted in a friction spinning machine, the aramid fiber conductive composite fiber is obtained; s2, wrapping the surface of the elastic core yarn with an aramid conductive composite fiber in a friction spinning manner to obtain a soft wear-resistant aramid multi-layer composite conductive covering yarn; and S3, wrapping ultra-high molecular weight polyethylene yarns on the surface of the soft wear-resistant aramid fiber multi-layer composite conductive core-spun yarn to obtain the wear-resistant aramid fiber multi-layer composite conductive core-spun yarn.

Description

Technical Field

[0001] The present invention belongs to the technical field of textiles, and particularly relates to a wear-resistant aramid multi-layer composite conductive core-spun yarn and a preparation method thereof. Background Art

[0002] With the development of science and technology and society, textiles have broken through the traditional requirements of comfort and beauty and gradually become a research hotspot towards multi-function and intelligent breakthroughs. In particular, flexible sensing intelligent textiles used to monitor and timely give feedback on human movement, physiological changes, etc. are widely used in real life. However, intelligent sensing textiles made of ordinary materials are difficult to be applied to extreme environments (high temperature, extreme cold, etc.) for a long time and are difficult to make a stimulus response in case of emergency. Therefore, it is of great significance to prepare intelligent textiles for extreme environments to monitor and feedback the vital signs and movement states of high-risk workers in case of danger and reduce the accident risk rate.

[0003] Aromatic polyamide fiber (referred to as aramid) is currently the main substrate used to construct high-performance fire protection textiles. Due to its excellent performance in terms of light weight, high specific strength, good impact resistance, heat resistance, chemical resistance, etc., aramid fiber materials are usually used in the market to manufacture yarns and fabrics, and are widely used in industries with high-strength protection requirements in cutting-edge fields such as national defense, high-end manufacturing, and safety protection. However, due to its strong insulation, the preparation methods and properties of aramid sensing yarns in the field of intelligent textiles still need to be developed and studied in depth. The existing aramid conductive modification processes usually have the following two types. One is the post-treatment method, depositing a conductive film on the surface of the yarn / fabric to endow it with conductivity. For example, patent CN103668944B discloses an aramid silver-plated conductive fiber and a preparation method thereof. This method has high requirements for environmental factors such as reagent concentration, reaction time, and temperature in the pretreatment, and the production process is complex. Although the conductive effect is improved, the treatment time is long, the impregnation modification efficiency is not high, the production quality and efficiency are low, and it is not conducive to large-scale production. Patent CN115613014A discloses a method for electroless silver plating on aramid fabrics. It is difficult to control the bonding strength and uniformity between the coating and the substrate, and good conductivity can only be achieved by operating on a substrate with a continuous surface. The production efficiency is low and it has a great impact on the appearance quality and hand comfort of the fabric. The other is to chemically modify the surface of aramid fibers. For example, patent CN103981720A proposes a polyaniline-modified aramid composite conductive fiber and a preparation method thereof. This chemical modification method has a complex preparation process, high operation difficulty, and a large number of toxic chemical reagents such as acetone pose potential hazards to the environment and human health.

[0004] Therefore, the researchers used traditional spinning technology to prepare a wear-resistant aramid multi-layer composite conductive core-spun yarn and its preparation method. They adopted a blending manufacturing method of electrospinning to manufacture nano-conductive fiber mixed with aramid fiber network, enhancing the electrical conductivity of aramid yarn at the micro-nano scale. The traditional spinning technology is mature, overcoming the disadvantages of complex modification preparation process and low efficiency of aramid conductive yarn. The multi-layer core-sheath structure design endows the yarn with ultra-high elasticity while ensuring the sensitive sensing and ultra-high protection performance of the aramid conductive composite yarn. The sensing yarn has a fast response speed, high sensitivity, excellent adaptability, structural stability and durability in a wide temperature environment. After a long time of cyclic stretching cyclic action, it remains stable, with good repeatability and stability, to adapt to body state monitoring under extreme cyclic strain. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a wear-resistant aramid multi-layer composite conductive core-spun yarn and its preparation method. The preparation method adopts a production process of electrospinning combined with friction spinning to manufacture aramid conductive composite yarn. Through the blending manufacturing method of electrospinning to manufacture nano-conductive fiber mixed with aramid fiber network, the conductive material and the aramid matrix are arranged densely and tightly combined, constructing an ultra-high conductive network of aramid yarn at the micro-nano scale. At the same time, the nanofibers enhance the contact and bonding between fibers and between the core-sheath layers, greatly improving the strength of the filament friction composite yarn and the structural stability of the formed yarn, and solving to a certain extent the problems such as poor fiber cohesion and serious electrostatic accumulation of aramid fibers.

[0006] The present invention provides a preparation method of a wear-resistant aramid multi-layer composite conductive core-spun yarn, comprising the following steps:

[0007] S1. Mix the conductive material dispersion and the spinning solution and load them into the spinning supply platform. Prepare a micro-nano conductive fiber network by electrospinning, and blend it with the aramid staple fiber sliver after drafting in a friction spinning machine to obtain aramid conductive composite fibers;

[0008] S2. Outerwrap the aramid conductive composite fibers on the surface of the elastic core yarn by friction spinning to obtain a soft and wear-resistant aramid multi-layer composite conductive core-spun yarn;

[0009] S3. Wrap the ultra-high molecular weight polyethylene yarn on the surface of the soft and wear-resistant aramid multi-layer composite conductive core-spun yarn to obtain a wear-resistant aramid multi-layer composite conductive core-spun yarn.

[0010] Further, in S1, the applied voltage of electrospinning is 15 - 20 kV, the nozzle diameter is 0.5 - 2 mm, the flow rate is 0.2 - 1.0 mL / min, the distance between the electrospinning nozzle and the receiving plate is 12 - 18 cm, and the rotation speed of the spinning solution stirring is 200 - 500 r / min.

[0011] Further, in S1, the solute in the spinning solution is PAN powder, the solvent is DMF, and the ratio of the solute to the solvent is 0.5 - 5 g: 10 mL.

[0012] Further, in S1, the conductive material dispersion is a carbon nanotube dispersion with a weight percentage of 2 - 5 wt%, and the concentration of the conductive material dispersion after mixing with the spinning solution is 15 - 30 wt%.

[0013] Further, in S2, the elastic yarn is one or more of elastic filaments such as spandex filaments and rubber filaments, and the fineness is one or more of 100D, 150D, and 200D.

[0014] Further, in S2, during the friction spinning process, the speed of the carding roller is 2000 r / min - 4000 r / min, the speed of the friction roller is 3000 r / min - 4000 r / min, the feeding speed is 0.5 m / min - 1.5 m / min, and the speed ratio of the aramid conductive composite fiber and the elastic core yarn is 3:7 - 3:1.

[0015] Further, in S3, the fineness of the ultra-high molecular weight polyethylene yarn is one or more of 40D, 50D, 60D, and 80D. The spindle speed of the ring spinning and twisting is 4100 - 4300 r / min, the output linear speed is 7 - 10 m / min, and the wrapping density is 600 - 1000 T.

[0016] Further, in S3, the ultra-high molecular weight polyethylene yarn can be replaced by any one of polyimide yarn, PTFE yarn, basalt yarn, carbon fiber yarn, and alumina yarn.

[0017] Further, in S2, the linear density of the flexible and wear-resistant aramid multi-layer composite conductive core-spun yarn is 30 - 80 dtex, the elastic elongation rate is 10 - 60%, and the resistivity decays by 1 - 10% after 5000 stretching cycles.

[0018] The present invention also provides a wear-resistant aramid multi-layer composite conductive core-spun yarn obtained by the above preparation method.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. The present invention adopts the electrospinning process. Electrospinning can effectively control the fine structure of fibers, is easy to blend with aramid fibers to manufacture conductive composite yarns, enhances the conductive performance of aramid yarns at the micro-nano scale, endows them with high conductivity and mechanical stability, and overcomes the disadvantages of complex preparation processes and low efficiency such as surface chemical modification of aramid conductive yarns.

[0021] 2. The present invention adopts the friction spinning process to achieve a layered core-sheath structure of conductive elastic yarn. The inner-layer elastic yarn endows the aramid conductive yarn with super elasticity. The conductive PAN / carbon nanotube fibers wind and interlock with the aramid fibers, enhancing the cohesive force between the fibers, improving the strength of the friction composite yarn and the stability of the yarn structure, significantly enhancing the bonding strength between the aramid fibers and the active conductive material. The conductive path is complete and stable. The outer-layer blended structure also improves the hand comfort and wearing fit performance of the aramid composite fiber yarn, showing great application prospects in the field of smart wear.

[0022] 3. The outer-layer ultra-high molecular weight polyethylene yarn can protect the inner-layer aramid conductive elastic yarn, improving the abrasion resistance and fracture resistance of the yarn. At the same time, the composite yarn prepared by the wrapping process makes up for the disadvantage of insufficient stretchability of the ultra-high molecular weight polyethylene yarn, endowing excellent wearing comfort and support performance.

[0023] 4. The wear-resistant aramid multi-layer composite conductive core-spun yarn described in the present invention not only exhibits excellent conductivity but also has reliable structural stability during the stretching and recovery process, with high tensile elasticity and reusability. The protective fabric prepared with this composite yarn solves the disadvantages of poor conductivity and comfort of traditional protective materials, enabling it to have the functions of safety protection and motion monitoring in extreme environments. Moreover, the method of the present invention is simple to operate and has low production costs, showing the potential for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 It is a flowchart for the preparation of the wear-resistant aramid multi-layer composite conductive core-spun yarn in Embodiment 1 of the present invention.

[0026] Figure 2 It is a schematic structural diagram of the wear-resistant aramid multi-layer composite conductive core-spun yarn in Embodiment 1 of the present invention.

[0027] Figure 3 It is the resistance of the wear-resistant aramid multi-layer composite conductive core-spun yarn prepared at different collection speeds in Embodiment 2 of the present invention.

[0028] Figure 4 It is the relationship between the strain and resistance change of the wear-resistant aramid multi-layer composite conductive core-spun yarn prepared at different coating densities of ultra-high strength molecular weight polyethylene yarn in Embodiment 3 of the present invention.

[0029] Figure 5It is the strain sensitivity of the wear-resistant aramid multi-layer composite conductive core-spun yarn prepared in Example 3 of the present invention.

[0030] Figure 6 It is the sensing stability of the wear-resistant aramid multi-layer composite conductive core-spun yarn prepared in Example 3 of the present invention. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Example 1

[0033] Refer to Figure 1 As shown, a preparation method of a wear-resistant aramid multi-layer composite conductive core-spun yarn includes the following steps:

[0034] S1. The aramid fiber strips are led out from the creel and co-fed into a three-roller drafting device for co-drafting, and their uniformity and fiber straightness are improved to a certain extent; the electrospinning liquid supply platform is filled with spinning liquid, and the preparation method is as follows: PAN powder is added to DMF and heated and dissolved at 80 °C for 4 h to obtain a PAN solution; the conductive material is a 3 wt% carbon nanotube dispersion (CNT), which is mixed with the PAN solution and heated and dissolved and stirred at 60 °C to obtain a uniform PAN / CNT spinning liquid; under the action of high-voltage static electricity between the electrostatic spinning head and the receiving surface of the receiver, a large number of micro-nano fibers are generated on the nozzle to form a PNA / CNT nano-conductive fiber network, which is mixed with the aramid staple fiber sliver passing through the receiver to form an aramid / PNA / CNT conductive network fiber sliver. The content of PNA / CNT nano-conductive fibers is controlled by controlling the collection speed of the fiber sliver, and its speed is set to 0.5 m / min. The micro-nano fibers are accompanied by the aramid fiber web under the dual action of electric field force and the air flow of the air duct to form a blended composite fiber web; during the conveying process, the composite fiber web is condensed on the dust cage under the action of negative pressure adsorption, uniformly mixed and then separated into single fiber state by a licker-in; then it is prepared into aramid / PNA / CNT conductive roving through processes such as drawing.

[0035] S2. Unwind the spool of spandex elastic filament, pass it through a yarn guide and a tensioner, stretch it to 150% of its original length, and feed it axially into the middle of the friction rollers by a friction spinning machine. Under the action of the negative pressure suction of the inner liner inside a pair of friction roller cylinders of the friction spinning machine, the aramid / PMMA / CNT conductive network fibers after drafting, carding, and dispersion enter between the pair of friction roller cylinders along the outer wall surface of the friction roller, are transported and wrapped around the spandex filament. Two mutually pressed and co-rotating at high speed dust cages friction-twist to form yarns, which are fed into the friction spinning machine at a speed of 0.6 m / min respectively, and are carded by carding rollers into short fiber strands with different coating thicknesses, evenly and tightly coated on the outer layer of the electrode core yarn, and aramid sensing network elastic yarns of 45 tex are obtained respectively; the output speed is 5 m / min, the speed of the carding roller is 3500 r / min, and the speed of the friction roller is 4500 r / min. Then, it passes through the draw roller, yarn guide, and winding grooved drum in sequence, and is finally wound onto the bobbin. The spindle speed during twisting and winding is 4400 r / min; finally, aramid conductive elastic yarns are obtained.

[0036] S3. Use a hollow spindle wrapping spinning machine to complete the preparation according to the following steps. The aramid conductive elastic yarn bobbin unwinds at a certain speed under the friction drive of the feed roller. The core yarn passes through the yarn guide eye, bypasses the yarn guide roller, and passes through the central tube of the hollow spindle under the action of the endless belt, and meets the ultra-high molecular weight polyethylene yarn at the yarn guide hook. The ultra-high molecular weight polyethylene yarn wound on the aluminum bobbin unwinds at a certain speed under the drive of the endless belt with the hollow spindle, and the ultra-high molecular weight polyethylene yarn is spirally wound around the aramid conductive yarn under the drive of the output roller, and a wear-resistant aramid multi-layer composite conductive core-spun yarn with a wrapped structure is formed as the yarn is continuously drawn out. The unwinding line speed is 7 m / min, the spindle speed of the hollow spindle is 4500 r / min, and the wrapping twist is set to 700 T. Finally, a wear-resistant aramid multi-layer composite conductive core-spun yarn is obtained.

[0037] The wear-resistant aramid multi-layer composite conductive core-spun yarn provided by the present invention has a multi-layer core-sheath structure, referring to Figure 2 as shown in the structural schematic diagram, wherein the core layer is a spandex filament elastic layer, the middle layer is an aramid / PAN / CNT composite nanofiber conductive network layer, and the outer layer is an ultra-high molecular weight polyethylene wear-resistant layer.

[0038] The friction spinning machine provided by the present invention includes a carding roller, and an electrospinning device is arranged at the front end of the carding roller of the carding roller, including a receiving device and an electrostatic spinning device. One end of the receiving device is a fixing plate, which is fixedly connected to the outer surface below the pipe wall at the inlet end of the carding plate through an insulating glue, and the other end is a planar receiving plate. The electrostatic spinning head is located above the receiving plate, and an electrospinning area is formed between the spinning head and the receiver. The electrostatic spinning head is connected to the metering pump of the electrospinning device through a connecting pipe.

[0039] Example 2

[0040] Refer toFigure 1 As shown, an abrasion-resistant aramid multi-layer composite conductive core-spun yarn prepared by the described method, and the specific preparation method includes the following steps:

[0041] S1. Draw out the aramid fiber strips from the creel, and co-feed them into a three-roller drafting device for co-drafting, which can improve the uniformity and fiber straightness to a certain extent; the electrospinning liquid supply table is filled with spinning solution, and the preparation method is as follows: Add PAN powder to DMF, stir and swell at 30 °C for 6 h, and heat and dissolve at 80 °C for 24 h to obtain a PAN solution; the conductive material is a 3 wt% carbon nanotube dispersion (CNT), after mixing with the PAN solution, heat and dissolve and stir at 60 °C to obtain a uniform PAN / CNT spinning solution; under the action of high-voltage static electricity between the electrostatic spinneret and the receiving surface of the receiver, a large number of micro-nano fibers are generated on the spinneret to form a PNA / CNT nano-conductive fiber network, which is mixed with the aramid staple fiber sliver passing through the receiver to form an aramid / PMMA / CNT conductive network fiber sliver. Control the content of PNA / CNT nano-conductive fibers by controlling the collection speed of the fiber sliver, and set its speed to 0.5, 1, 1.5, and 2 m / min. The micro-nano fibers are accompanied by the aramid fiber web under the dual action of electric field force and the air flow of the air duct to form a blended composite fiber web; during the conveying process, the composite fiber web is condensed on the dust cage under the action of negative pressure adsorption, and after uniform mixing, it is separated into single fiber state by the carding roller; then it is prepared into aramid / PNA / CNT conductive roving through processes such as drawing.

[0042] S2. Unwind the spool of spandex elastic filament, pass it through the yarn guide and tensioner, stretch it to 150% of its original length, and the friction spinning machine feeds it axially into the middle of the friction roller. The aramid / PMMA / CNT conductive network fiber sliver after drafting, carding and dispersion enters between the pair of friction roller cylinders along the outer wall surface of the friction roller under the action of the negative pressure suction of the inner liner inside the pair of friction roller cylinders in the friction spinning machine, and is transported and wrapped around the spandex filament. Two mutually pressed and co-rotating at high speed dust cages friction and twist to form yarn, and are fed into the friction spinning machine at a speed of 0.6 m / min respectively, and are carded by the carding roller into short fiber strands with different wrapping thicknesses, which are evenly and tightly wrapped on the outer layer of the electrode core yarn to obtain 45 tex aramid sensing network elastic yarn respectively; the output speed is 5 m / min, the speed of the carding roller is 3500 r / min, and the speed of the friction roller is 4500 r / min. Then it passes through the draw roller, yarn guide, and winding grooved drum in sequence, and is finally wound onto the bobbin. The spindle speed during twisting and winding is 4400 r / min; finally, aramid conductive elastic yarn is obtained.

[0043] S3. Use a hollow spindle covering spinning machine to complete the preparation according to the following steps. The aramid conductive elastic yarn package unwinds at a certain speed under the frictional drive of the feeding roller. The core yarn passes through the yarn guide eye, bypasses the yarn guide roller, and passes through the central tube of the hollow spindle under the action of the endless belt, and meets the ultra-high molecular weight polyethylene yarn at the yarn guide hook. The ultra-high molecular weight polyethylene yarn wound on the aluminum ingot tube unwinds at a certain speed under the drive of the hollow spindle by the spindle belt. Driven by the output roller, the ultra-high molecular weight polyethylene yarn is spirally wound on the aramid conductive yarn. As the yarn is continuously drawn out, a wear-resistant aramid multi-layer composite conductive core-spun yarn with a wrapped structure is formed. The unwinding line speed is 7 m / min, the spindle speed of the hollow spindle is 4500 r / min, and the wrapping twist is set to 700 T. Finally, a wear-resistant aramid multi-layer composite conductive core-spun yarn is obtained. Finally, the wear-resistant aramid multi-layer composite conductive core-spun yarns prepared at the collection speeds of different fiber slivers are named 0.5-wear-resistant aramid multi-layer composite conductive core-spun yarn, 1.0-wear-resistant aramid multi-layer composite conductive core-spun yarn, 1.5-wear-resistant aramid multi-layer composite conductive core-spun yarn, and 2.0-wear-resistant aramid multi-layer composite conductive core-spun yarn.

[0044] In this embodiment, wear-resistant aramid multi-layer composite conductive core-spun yarns with different conductivities are finally obtained by preparing PNA / CNT nano-conductive fibers with different contents; the resistance of a 10-cm wear-resistant aramid composite yarn is measured. As Figure 3 shown, it can be found that the resistance gradually increases with the increase of speed in the figure. This is because too high a drafting speed results in a small content of PNA / CNT nano-conductive fibers. From the test results, it is found that when the collection speed of the fiber sliver is 0.5 m / min, the conductive performance of the wear-resistant aramid multi-layer composite conductive core-spun yarn is the best.

[0045] Example 3

[0046] Refer to Figure 1 shown. A preparation method of a wear-resistant aramid multi-layer composite conductive core-spun yarn, and the specific preparation method includes the following steps:

[0047] S1. Draw out the aramid fiber strips from the creel, combine and feed them into a three-roller drafting device for combined drafting, which can improve the evenness and fiber straightness to a certain extent. The electrospinning liquid supply platform is filled with spinning solution, and the preparation method is as follows: Add PAN powder into DMF, stir and swell at 30°C for 6 h, and heat and dissolve at 80°C for 24 h to obtain a PAN solution; The conductive material is a 3wt% carbon nanotube dispersion (CNT). After mixing with the PAN solution, heat and dissolve with stirring at 60°C to obtain a uniform PAN / CNT spinning solution; Under the action of high-voltage static electricity between the electrostatic spinning head and the receiving surface of the receiver, a large number of micro-nano fibers are generated on the spinning head to form a PNA / CNT nano-conductive fiber network. After mixing with the aramid staple fiber sliver passing through the receiver, an aramid / PAN / CNT conductive network fiber sliver is formed. The content of PNA / CNT nano-conductive fibers is controlled by controlling the collection speed of the fiber sliver, and its speed is set to 0.5 m / min. The micro-nano fibers are accompanied by the aramid fiber web under the dual action of electric field force and the air flow of the air duct to form a blended composite fiber web; During the conveying process, the composite fiber web is condensed on the dust cage under the action of negative pressure adsorption, and after uniform mixing, it is separated into single fiber state by the carding roller; Then it is prepared into aramid / PNA / CNT conductive roving through processes such as drawing.

[0048] S2. Unwind the spool of spandex elastic filament, pass it through the yarn guide and tensioner, and stretch it to 150% of its original length. The friction spinning machine feeds it axially into the middle of the friction roller. Under the action of the negative pressure suction of the inner liner inside a pair of friction roller cylinders in the friction spinning machine, the aramid / PAN / CNT conductive network fiber sliver after drafting, carding and dispersion enters between the pair of friction roller cylinders along the outer wall surface of the friction roller, is conveyed and wrapped around the spandex filament. Two mutually pressed and co-rotating dust cages rub and twist to form yarn, which is fed into the friction spinning machine at a speed of 0.6 m / min respectively, and is carded by the carding roller into short fiber strands with different coating thicknesses, which are evenly and tightly coated on the outer layer of the electrode core yarn to obtain 45 tex aramid sensing network elastic yarn respectively; The output speed is 5 m / min, the speed of the carding roller is 3500 r / min, and the speed of the friction roller is 4500 r / min. Then it passes through the draw-off roller, yarn guide, and winding grooved drum in sequence, and is finally wound onto the bobbin. The spindle speed during twisting and winding is 4400 r / min;

[0049] S3. Use a hollow spindle wrapped spinning machine to complete the preparation according to the following steps. The aramid conductive elastic yarn bobbin unwinds at a certain speed under the frictional drive of the feeding roller. The core yarn passes through the yarn guide eye, bypasses the yarn guide roller, and passes through the central tube of the hollow spindle under the action of the endless belt, and meets the ultra-high molecular weight polyethylene yarn at the yarn guide hook. The ultra-high molecular weight polyethylene yarn wound on the aluminum ingot tube unwinds at a certain speed with the hollow spindle driven by the spindle belt. Driven by the output roller, the ultra-high molecular weight polyethylene yarn is spirally wound on the aramid conductive yarn. As the yarn is continuously drawn out, a wear-resistant aramid multi-layer composite conductive core-spun yarn with a wrapped structure is formed. The unwinding line speed is 7 m / min, the spindle speed of the hollow spindle is 4500 r / min, and the wrapping twist is set to 700 T, 750 T, 800 T, and 850 T. Finally, the wear-resistant aramid multi-layer composite conductive core-spun yarns prepared with different wrapping densities are named 700-wear-resistant aramid multi-layer composite conductive core-spun yarn, 750-wear-resistant aramid multi-layer composite conductive core-spun yarn, 800-wear-resistant aramid multi-layer composite conductive core-spun yarn, and 850-wear-resistant aramid multi-layer composite conductive core-spun yarn.

[0050] Prepare wear-resistant aramid multi-layer composite conductive core-spun yarns with different wrapping densities by setting different wrapping densities of ultra-high molecular weight polyethylene yarns; place the wear-resistant aramid multi-layer composite conductive core-spun yarn between digital slides, connect the LRC bridge at both ends, and stretch at a speed of 200 mm / min, and record the change of the electrical signal at different strains; as Figure 4 shown, the relative change of the electrical signal increases with the increase of the tensile strain, and it can be seen that the yarn capacitive sensor exhibits accurate and continuous sensing ability, and has a large tensile deformation at a wrapping twist of 700 T. At the same time, with the increase of the wrapping density, the yarn strain gradually decreases, because with the increase of the twist, the outer yarn restricts the deformation of the core elastic yarn.

[0051] Test Example 1

[0052] Based on the wear-resistant aramid multi-layer composite conductive core-spun yarn prepared in Example 1, test the change of the resistance signal of the wear-resistant aramid multi-layer composite conductive core-spun yarn under tension, which specifically includes the following steps: Place the wear-resistant aramid multi-layer composite conductive core-spun yarn on the moving slide, and connect a digital multimeter at one end, and stretch it to 50% of its original length at a speed of 200 mm / min. The result is as Figure 5 shown. From Figure 5 it can be seen that the maximum sensitivity of the wear-resistant aramid multi-layer composite conductive core-spun yarn is 1.34. This is because the resistance changes due to the continuous contact and separation of PAN / CNT fibers during the stretching process.

[0053] At the same time, the cyclic stability test of the wear-resistant aramid multi-layer composite conductive core-spun yarn was carried out; the wear-resistant aramid multi-layer composite conductive core-spun yarn was cycled 5000 times under a constant 45% tensile strain (tensile speed of 200 mm / min) to evaluate the durability and cyclic stability of the composite yarn as a sensor. From Figure 6 The measurement results show that the ΔR / R0 value experiences almost the same rising cycle and falling cycle throughout the period, indicating that the sensor has stable and repeatable strain sensing performance.

[0054] Obviously, the above embodiments are only examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing a wear-resistant aramid multilayer composite conductive core-spun yarn, characterized in that: The following steps are involved: S1, loading the conductive material dispersion mixed with the spinning solution into a spinning solution supply table, preparing a micro-nano conductive fiber network by electrospinning, and blending it with the aramid short fiber whiskers drawn in a friction spinning machine to obtain aramid conductive composite fibers; S2. The surface of the elastic core yarn is covered with aramid conductive composite fibers by friction spinning to obtain a soft and wear-resistant aramid multilayer composite conductive core yarn; S3. The wear-resistant aramid multi-layer composite conductive core-spun yarn is obtained by wrapping ultra-high molecular weight polyethylene yarn on the surface of the soft and wear-resistant aramid multi-layer composite conductive core-spun yarn.

2. The method for preparing a wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 1, characterized in that: In S1, the applied voltage of electrospinning is 15-20 kV, the nozzle diameter is 0.5-2 mm, the flow rate is 0.2-1.0 mL / min, the distance between the electrospinneret and the receiving electrode is 12-18 cm, and the speed of stirring the spinning solution is 200-500 r / min.

3. The method for preparing a wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 1, characterized in that: In S1, the solute in the spinning solution is PAN powder, the solvent is DMF, and the ratio of solute to solvent is 0.5-5 g:10 mL.

4. The method for preparing the wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 3, characterized in that: In S1, the conductive material dispersion is a carbon nanotube dispersion with a weight percentage of 2-5 wt%. After the conductive material dispersion is mixed with the spinning solution, the concentration of the conductive material dispersion is 15-30 wt%.

5. The method for preparing the wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 1, characterized in that: In S2, the stretch yarn is one or more of spandex filaments, rubber filaments and other elastic filaments, and the fineness is one or more of 100D, 150D and 200D.

6. The method for preparing the wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 1, characterized in that: In S2, during the friction spinning process, the speed of the combing roller is 2000r / min~4000r / min, the speed of the friction roller is 3000r / min~4000r / min, the feeding speed is 0.5m / min~1.5m / min, and the speed ratio of the aramid conductive composite fiber and the elastic core yarn is 3:7~3:

1.

7. The method for preparing the wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 1, characterized in that: In S3, the fineness of the ultra-high molecular weight polyethylene yarn is one or more of 40D, 50D, 60D and 80D, the spindle speed of the ring twisting is 4100-4300r / min, the output line speed is 7-10m / min, and the wrapping density is 600-1000T.

8. The method for preparing the wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 7, characterized in that: In S3, the ultra-high molecular weight polyethylene yarn can be replaced by any one of polyimide yarn, PTFE yarn, basalt yarn, carbon fiber yarn, and alumina yarn.

9. The method for preparing the wear-resistant aramid multi-layer composite conductive core-spun yarn according to claim 1, characterized in that: In S2, the linear density of the soft and wear-resistant aramid multi-layer composite conductive core-spun yarn is 30 to 80 dtex, the elastic elongation is 10 to 60%, and the resistivity decays by 1 to 10% after 5000 stretching cycles.

10. A wear-resistant aramid multi-layer composite conductive core-spun yarn, which is unique in that it is obtained by the preparation method described in any one of claims 1 to 9.

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