CN102703998A - Jet yarn spinning device for electrostatic spun nano fiber and preparing method - Google Patents

Abstract

The invention discloses an air-jet spinning device for electrostatically spinning nanofibers. There is a buncher, and two spinning devices are located between the gathering device and the buncher, and they are arranged symmetrically along the axis. There is a nozzle twister under the buncher, a yarn delivery roller under the nozzle twister, and a yarn delivery roller under the yarn delivery roller. There is a winding mechanism, and the gathering device, bundler, nozzle twister and yarn delivery roller are arranged along the same axis from top to bottom. The electrospinning nanofiber yarn forming device of the present invention integrates spinning, gathering, drafting, twisting and winding, and can continuously prepare electrospinning nanofiber yarns. The nanofiber yarn forming method of the invention has simple process and high yarn yield, is suitable for various polymer spinning solutions, and can realize continuous and large-scale preparation of nanofiber yarns.

Description

Air-jet spinning yarn forming device and preparation method of electrospun nanofiber

technical field

The invention belongs to the field of textile machinery, and relates to an electrospinning nanofiber yarn forming device and method, in particular to an air-jet spinning yarn forming device and method capable of continuously preparing electrospinning nanofiber yarns.

Background technique

Electrospinning technology is the most effective method for preparing nanofibers. The principle of electrospinning is that under the action of an electrostatic field, the polymer droplets located at the spinneret become Taylor cones. When the electrostatic field force exceeds the surface tension of the liquid Threshold, a good charged jet will be formed, which will be accelerated, drawn, and thinned, and nanofibers will be formed after the solvent volatilizes. Due to different metal collection devices, nanofiber mats of different shapes can be obtained. Although electrospun nanofiber mats can be directly used in many aspects such as filter materials, tissue engineering scaffolds, drug delivery materials, biomimetic materials, composite reinforcement materials, etc., for the textile industry, continuous fiber nanofiber yarns have a wide range of applications. value, because only yarn-based fabrics, knitted fabrics, braids and other more diverse nanofiber products and applications can be obtained.

At present, there have been some reports of electrospinning nanofibers into yarns. For example, Chinese patent 200510038571.5 discloses a preparation method of nanofiber filament bundles. The metal needles placed oppositely are used to connect the positive and negative electrodes respectively, and the fibers ejected from the two needles are Attract and collide with each other in the air to form composite nanofibers, which are stretched and wound onto a rotating drum to form nanofiber tows. In this method, the fibers in the filament tows are continuous and well arranged but have no twisting effect, and are not strictly yarns. . Chinese patent 200810018267.8 discloses an electrospinning nanofiber yarn system and a method for preparing nanofiber yarn. Electrospun nanofibers are deposited on a slotted disc, and then twisted to obtain nanofiber yarns after being drawn out by lead wires and godet rollers. , in this patent, the fibers cannot be completely gathered in the groove, resulting in waste of fibers. In addition, the disc needs to be cut with a cutter at the position where the nanofiber bundle is pulled out once every revolution of the disc. The process is relatively complicated and lacks stability and continuity. Zhang [Kai Zhang, Journal of Polymer Science: Part B: Polymer Physics, 2010, 48, 1118] et al used a grounded metal needle tip as an auxiliary electrode to guide fiber bundles to achieve continuous collection of untwisted PLLA, PAN, PMIA nanofiber aggregates , but the conductivity of the polymer solution in the collection device has an important impact on fiber aggregation, and it is only suitable for the formation of polymers with a certain range of conductivity. Smit [Eugene Smit, Polymer, 2005, 46, 2419] et al. first proposed electrospinning with a water bath as the receiving device, collecting nanofibers through the water surface, and stretching the fiber aggregates to form fiber bundles by means of the surface tension of the fibers in the bath and the coagulation bath . Teo [Wee-Eong Teo, Polymer, 2007, 48, 3400] etc. improved the water bath receiving device, using dynamic water as a coagulation bath, and realized the bundle and twisting of fibers through vortex action, and the efficiency of collecting nanofibers in water bath is relatively high. High, but only for water-insoluble polymer yarns. The above methods all use the traditional single needle as the spinneret, the output is only 0.1-1g/h, and the nanofiber yarn cannot be obtained stably and continuously, and there is a problem that the fibers in the yarn cannot be well oriented.

Contents of the invention

The purpose of the present invention is to provide an air-jet spinning device for electrospinning nanofibers, which can continuously prepare nanofiber yarns with better fiber alignment, and provide a method for preparing nanofiber yarns using the above-mentioned air-jet spinning device.

The technical solution of the present invention is: an air-jet spinning device for electrospinning nanofibers, which includes a gathering device. There is a concentrator under the device, and the two spinning devices are located between the concentrating device and the concentrator, and are arranged symmetrically along the axis. A nozzle twister is provided under the concentrator, and a yarn delivery roller is provided under the nozzle twister. A winding mechanism is arranged below the rollers, and the gathering device, bundler, nozzle twister and yarn drawing rollers are arranged along the same axis from top to bottom.

The spinneret is formed by connecting an air chamber with an air inlet on one side and a solution chamber with a liquid inlet on one side through an intermediate connecting body, the intermediate connecting body is provided with a vertically upward air spray pipe, and the solution The chamber is provided with spinnerets vertically upward.

The air chamber and the solution chamber are cylindrical; the spinneret and the air jet pipe are at least one, and they are arranged in concentric circles, and each spinneret corresponds to a concentric air jet pipe to ventilate it, and the air jet pipe The height is lower than the upper surface of the spinneret and higher than the upper surface of the solution chamber, the inner diameter of the spinneret is 1-40mm, and the distance is 0.1-15cm.

The gathering device is a metal disc or a horn with a rotating shaft, which is controlled by a transmission mechanism to rotate around the shaft, and the diameter of the metal disc or horn mouth is 1-2 times the diameter of the upper surface of the solution chamber in the spinneret; The inlet to the outlet of the cluster is in the shape of a horn whose diameter gradually narrows, and the diameter of the outlet is 0.8-8mm.

The nozzle twister is composed of an air inlet pipe, an air chamber, an injection hole, a yarn path, an intermediate pipe and an outlet pipe. The injection hole is tangent to the inner circumference of the yarn path, and the diameter of the injection hole is 0.1-0.55mm , the angle with the yarn path is 30-50°, and the number of injection holes is 2-8; the diameter of the yarn path above the injection hole entrance is 0.8-2.0mm, the length is 8-15mm, and it is below the injection hole entrance The diameter of the pipe is 2.0-3.5mm and the length is 8-15mm; the diameter of the middle pipe is 3.0-6.0mm and the length is 8-15mm; the diameter of the outlet pipe is 5.0-10.0mm and the length is 5-12mm.

The included angle between the spinneret and the axis is 15-40°; the outlet of the cluster is connected to the entrance of the yarn path in the nozzle twister; the distance between the upper end faces of the center spinnerets of the two spinnerets is 5° -50cm, the distance from the central position of the gathering device is 6-60cm; the distance between the entrance of the yarn path of the nozzle twister and the gathering device is 15-100cm.

The voltage of the high-voltage electrostatic generator is 10-200kV, and the positive pole and the negative pole are respectively connected with the metal spinnerets in the two spinnerets.

The spinneret of the spinneret is made of metal, and the rest are insulating materials, and the outside of the spinneret is also covered with insulating materials.

The method for preparing nanofiber yarn by the air-jet spinning device, its steps are as follows:

a. Use a peristaltic pump or other constant-speed liquid supply device to input the polymer spinning solution into the solution chamber at a uniform speed through the liquid inlet. The liquid level of the spinning solution is lower than the upper end surface of the spinneret and higher than the upper end surface of the air jet tube ;

b. Use a cross-flow air pump or other constant-velocity ventilation device to continuously output gas to the air chamber through the air inlet, and the gas is sprayed upward through the jet pipe, and the spinning solution forms a hollow solution protrusion on the upper end of the spinneret;

c. Open the transmission mechanism of the accumulation device, the accumulation device rotates around the shaft, and the control speed is 10-2000 rpm;

d. Turn on the high-voltage electrostatic generator and adjust it to a certain voltage. The positive and negative poles of the high-voltage electrostatic generator are respectively connected to the metal spinnerets in the two spinning devices, and the gathering device is not grounded. Under the action of a high-voltage electric field, the polarized charge gathers on the top of the solution protrusion on the spinneret to form a Taylor cone. The jet with the opposite charge is emitted, and the nanofibrous web is deposited on the edge of the gathering device through electrostatic drawing, attraction and neutralization;

e. Lead out, orient and twist the nanofiber web in step (c), an insulating plastic rod is placed in the center of the gathering device in advance, and the plastic rod is slowly drawn out backwards along the horizontal direction to form a hollow conical nanofiber The top end is attached to the plastic rod, and the bottom end is connected to the edge of the gathering device, and the cone top of the nanofiber net is further drawn, and the fibers are oriented and gathered into nanofiber bundles, or further pre-twisted into nanofiber bundles by the rotation of the gathering device. A nanofiber strip with a certain twist;

f. Connect the air inlet pipe of the nozzle twister with the air compressor, and the compressed air is injected into the yarn path through the injection hole, forming a high-speed rotating airflow in the yarn path, and forming a negative pressure at the entrance of the yarn path. The nanofiber bundle (or nanofiber strip) in step (d) is introduced into the bundler, and the nanofiber bundle is sucked into the yarn path due to the negative pressure, twisted into yarn under the action of the rotating air flow and passed along the yarn path and through the middle Pipe, output from the outlet pipe;

g. The nanofiber yarn twisted in step (e) is output under the action of the yarn drawing roller, and wound into a tube by a winding mechanism.

The direction of rotation of the gathering device is the same as the direction of rotation of the jet air in the yarn path of the nozzle twister, and the twist of the nanofiber yarn can be completed independently by the high-speed rotation of the jet air in the yarn path, or by the jet air in the yarn path of the nozzle twister. The high-speed rotation of the machine is completed together with the rotation of the gathering device.

The beneficial effects of the present invention are: the electrospinning nanofiber yarn forming device of the present invention integrates spinning, gathering, drafting, twisting and winding, and can continuously prepare electrospinning nanofiber yarns. The spinneret solution of the present invention is in a closed system, which reduces the volatilization of the solvent in the solution and can maintain a stable solution concentration. The spinneret has a large aperture, and the continuous ventilation through the jet tube prevents the flow of the gas from the spinneret. A single spinneret can eject multiple jets, and multiple spinnerets can spray at the same time, which greatly improves the yield of electrospun nanofibers; the gathering device is located between the positive and negative jets ejected from the two spinnerets The intersection point can well deposit and gather the nanofibers after the neutralization of the charge, and the rotation of the gathering device can also play a twisting effect on the nanofiber bundles; twisting by using the high-speed rotating airflow in the nozzle twister does not require For other complex twisting parts, the twister has a simple structure and high production efficiency; the fineness of the nanofiber yarn can be controlled by controlling the liquid inlet speed of the solution, the ventilation speed, the speed of the gathering device, the air pressure and the flow rate in the twister. Degree, twist and output are controlled. The nanofiber yarn forming method of the invention has simple process and high yarn yield, is suitable for various polymer spinning solutions, and can realize continuous and large-scale preparation of nanofiber yarns.

Description of drawings

Figure 1 is an electrospinning nanofiber air-jet spinning device, wherein the gathering device is a disc made of metal;

Figure 2 is an electrospinning nanofiber air-jet spinning device, wherein the gathering device is a horn made of metal;

Fig. 3 is the schematic structural view of the spinning device in the electrospinning nanofiber air-jet spinning device;

Fig. 4 is the structural representation of the nozzle twister in the electrospinning nanofiber air-jet spinning device of the present invention;

Figure 5 is an electron micrograph of electrospun PAN nanofiber yarn, with a magnification of 500 times;

Figure 6 is an electron micrograph of electrospun PAN nanofiber yarn, with a magnification of 5000 times;

Among them: 1. Spinning device; 2. Gathering device; 3. Concentrator; 4. Nozzle twister; 5. Yarn drawing roller; 6. Winding mechanism; 7. High-voltage electrostatic generator; 8. Air chamber; 9 1, spinneret; 10, jet tube; 11, air inlet; 12, liquid inlet; 13, intermediate connector; 14, solution chamber; 15, injection hole; 16, yarn path; 17, intermediate tube; 18, Outlet pipe; 19, air chamber; 20, intake pipe.

Detailed ways

Example 1

As shown in Figure 1, Figure 3 and Figure 4, an air-jet spinning device for electrospinning nanofibers includes a spinning device 1, a gathering device 2, a bundler 3, a nozzle twister 4, a yarn drawing roller 5, Winding mechanism 6 and high voltage electrostatic generator 7.

The spinning device 1 is formed by connecting an air chamber 8 with an air inlet 11 on one side and a solution chamber 14 with a liquid inlet 12 on one side through an intermediate connecting body 13. The air chamber 8 and the solution chamber 14 are cylindrical. A vertically upward air spray pipe 10 is arranged on the intermediate connecting body 13 , and a vertically upward spinneret 9 is arranged on the solution chamber 14 . The number of spinnerets 9 and air jets 10 is 5, arranged in concentric circles, with 1 in the center and 4 on the sides. Each spinneret 9 corresponds to a concentric air jet 10 for ventilation, and the air jets 10 The height is lower than the upper surface of the spinneret 9, higher than the upper surface of the solution chamber 14. The inner diameter of the spinneret 9 is 8.0 mm, and the pitch is 5.0 cm. The spinneret 1 is made of an insulating material except that the spinneret 9 is made of metal, and the outer side of the spinneret 9 is also covered with an insulating material.

The gathering device 2 is a metal disc with a rotating shaft, which can be controlled by a motor or other transmission mechanism to rotate around the shaft. The diameter of the metal disc is twice the diameter of the upper surface of the solution chamber 14 in the spinning device 1 . From the inlet to the outlet of the cluster 3, the diameter is gradually narrowed in the shape of a trumpet, and the diameter of the outlet is 1.8 mm.

Nozzle twister 4 is made up of inlet pipe 20 , air chamber 19 , injection hole 15 , yarn path 16 , intermediate pipe 17 and outlet pipe 18 . The injection hole 15 is tangent to the inner circumference of the yarn path 16, and the aperture of the injection hole 15 is 0.38 mm, and the angle with the yarn path 16 is 45 °, and the number of injection holes is 6. Yarn path 16 has a diameter of 1.3 mm and a length of 8.0 mm above the injection hole 15 inlet, and a diameter of 2.3 mm and a length of 10 mm below the injection hole 15 inlet. The diameter of intermediate pipe 17 is 4.5 mm, and length 10 mm. The outlet tube 18 has a diameter of 8.0 mm and a length of 8.0 mm.

The gathering device 2, the buncher 3, the nozzle twister 4 and the yarn delivery roller 5 are arranged along the same axis from top to bottom. Two spinning devices 1 are located between the concentrating device 2 and the concentrator 3, symmetrically arranged opposite to each other along the axis, and the inclination angle of the spinning devices 1 (the included angle with the axis) is 30°. The outlet of the bundler 3 is connected to the inlet of the yarn path 16 in the nozzle twister 4 . The distance between the upper end faces of the center spinnerets 9 of the two spinnerets 1 is 12 cm, and the distance between the gathering device 2 (the center of the metal disc) is 10 cm, and the entrance of the nozzle twister 4 yarn path 16 The distance to the collection device 2 (the center of the metal disc) is 25 cm.

A method for preparing polyacrylonitrile (PAN) nanofiber yarns by an electrospinning nanofiber air-jet spinning device, comprising the following steps:

a. Dissolve PAN (weight average molecular weight 50,000) in N,N-dimethylformamide (DMF) to prepare a spinning solution with a mass concentration of 13.5%. Utilize a peristaltic pump to input the PAN solution into the solution chamber through the liquid inlet 12 at an even speed, and the liquid level of the PAN solution is lower than the upper end surface of the spinneret 9 and higher than the upper end surface of the jet pipe 10;

b. Utilize the cross-flow air pump to continuously output the gas to the air chamber 8 through the air inlet 11, the gas is sprayed upwards through the gas injection pipe 10, and the PAN solution forms a hollow solution protrusion on the upper end surface of the spinneret 9;

c, turn on the high-voltage electrostatic generator 7, adjust to a certain voltage, the positive pole and the negative pole of the high-voltage electrostatic generator 7 are connected with the spinneret 9 of metal material in the two spinnerets 1 respectively, and the gathering device 2 (metal round plate) is not grounded. Under the action of a high-voltage electric field, the polarized charges gather on the top of the solution protrusion on the spinneret 9 to form a Taylor cone, and the hollow Taylor cone breaks under the action of airflow pressure and electrostatic force, and multiple jets are ejected. The jets from the spinnerets 9 of the two spinnerets 1 are of opposite charge, neutralized due to electrostatic attraction and deposited in the form of nanofibrous webs on the edge of the collecting device 2 (metal disc);

d. In order to lead out, orient and twist the PAN nanofibrous web in step (c), an insulating plastic rod is placed in the center of the gathering device 2 (metal disc) in advance, and when the plastic rod slowly moves backward along the horizontal direction When pulled out, a hollow conical nanofibrous web will be formed, the top end will adhere to the plastic rod, and the bottom end will be connected to the edge of the collecting device 2 (metal disc). Further drafting the cone top of the nanofibrous web will cause the fibers to be oriented , aggregated into PAN nanofiber bundles;

e. Connect the air inlet pipe 20 of the nozzle twister 4 with the air compressor, and the compressed air is injected into the yarn path 16 from the injection hole 15, forming a high-speed rotating airflow in the yarn path 16, and forming Negative pressure. The PAN nanofiber bundles in step (d) are introduced into the bundler 3, and the PAN nanofiber bundles are sucked into the yarn path 16 due to the negative pressure, twisted into yarns under the action of the rotating air flow and passed along the yarn path 16, through the middle Pipe 17, output from outlet pipe 18;

f. The twisted PAN nanofiber yarn in step (e) is output under the action of the yarn drawing roller 5, and is wound into a tube by the winding mechanism 6.

In this example, the transmission mechanism of the accumulating device 2 is not opened, that is, the accumulating device 2 does not rotate around the shaft, therefore, the PAN nanofiber yarn is twisted solely by the high-speed rotation of the jet air in the yarn path 16. The electron micrographs of the prepared electrospun PAN nanofiber yarns are shown in Fig. 5 .

Example 2

As shown in Figure 2, Figure 3 and Figure 4, an air-jet spinning device for electrospinning nanofibers includes a spinning device 1, a gathering device 2, a bundler 3, a nozzle twister 4, a yarn drawing roller 5, Winding mechanism 6 and high voltage electrostatic generator 7.

The spinning device 1 is formed by connecting an air chamber 8 with an air inlet 11 on one side and a solution chamber 14 with a liquid inlet 12 on one side through an intermediate connecting body 13. The air chamber 8 and the solution chamber 14 are cylindrical. A vertically upward air spray pipe 10 is arranged on the intermediate connecting body 13 , and a vertically upward spinneret 9 is arranged on the solution chamber 14 . The number of spinnerets 9 and air jets 10 is 9, arranged in concentric circles, with 1 in the center and 8 on the sides. Each spinneret 9 corresponds to a concentric air jet 10 for ventilation, and the air jets 10 The height is lower than the upper surface of the spinneret 9, higher than the upper surface of the solution chamber 14. The inner diameter of the spinneret 9 is 12 mm, and the pitch is 4.0 cm. The spinneret 1 is made of an insulating material except that the spinneret 9 is made of metal, and the outer side of the spinneret 9 is also covered with an insulating material.

The gathering device 2 is a metal horn with a rotating shaft, which can be controlled by a motor or other transmission mechanism to rotate around the shaft. The diameter of the metal horn mouth is 1.8 times the diameter of the upper surface of the solution chamber 14 in the spinning device 1 . From the inlet to the outlet of the cluster 3, the diameter gradually narrows into a trumpet shape, and the diameter of the outlet is 2.0 mm.

Nozzle twister 4 is made up of inlet pipe 20 , air chamber 19 , injection hole 15 , yarn path 16 , intermediate pipe 17 and outlet pipe 18 . The injection hole 15 is tangent to the inner circumference of the yarn path 16, and the aperture of the injection hole 15 is 0.40 mm, and the angle with the yarn path 16 is 48 °, and the number of injection holes is 4. The diameter of the yarn path 16 above the injection hole 15 inlet is 1.6 mm, and the length is 10.0 mm. The diameter below the injection hole 15 inlet is 3.0 mm, and the length is 10 mm. The diameter of intermediate pipe 17 is 5.5 mm, and length 12 mm. The outlet tube 18 has a diameter of 10.0 mm and a length of 7.0 mm.

The gathering device 2, the buncher 3, the nozzle twister 4 and the yarn delivery roller 5 are arranged along the same axis from top to bottom. The two spinning devices 1 are located between the concentrating device 2 and the concentrator 3, symmetrically arranged opposite to each other along the axis, and the inclination angle of the spinning devices 1 (the included angle with the axis) is 35°. The outlet of the bundler 3 is connected to the inlet of the yarn path 16 in the nozzle twister 4 . The distance between the center spinnerets 9 upper faces of the two spinning devices 1 is 15 cm, and the distance between the gathering device 2 (the center of the bell mouth section) is 12 cm, and the nozzle twister 4 yarn paths 16 The distance between the inlet and the collecting device 2 (center of the bell section) is 32 cm.

A method for preparing polylactic acid (PLA) nanofiber yarns by an electrospinning nanofiber air-jet spinning device, comprising the following steps:

a. Dissolve PLA (weight average molecular weight: 80,000) in dichloromethane to prepare a spinning solution with a mass concentration of 8%. Utilize a peristaltic pump (not shown in the accompanying drawings) to input the PLA solution into the solution chamber through the liquid inlet 12 at a uniform speed, and the liquid level of the PLA solution is lower than the upper end surface of the spinneret 9 and higher than the upper end surface of the jet pipe 10;

b. Utilize the cross-flow air pump to continuously output the gas to the gas chamber 8 through the air inlet 11, the gas is sprayed upward through the gas injection pipe 10, and the PLA solution forms a hollow solution protrusion on the upper end surface of the spinneret 9;

c, open the transmission mechanism of the accumulating device 2, make it rotate around the shaft, the control speed is 600 rev/min;

d, open the high-voltage electrostatic generator 7, adjust to a certain voltage, the positive pole and the negative pole of the high-voltage electrostatic generator 7 are connected with the spinneret 9 of metal material in the two spinnerets 1 respectively, and the gathering device 2 (metal horn ) is not grounded. Under the action of a high-voltage electric field, the polarized charges gather on the top of the solution protrusion on the spinneret 9 to form a Taylor cone, and the hollow Taylor cone breaks under the action of airflow pressure and electrostatic force, and multiple jets are ejected. The jets ejected from the spinnerets 9 of the two spinnerets 1 have opposite charges, and due to electrostatic attraction, neutralize and deposit in the form of PLA nanofibrous webs on the edge of the gathering device 2 (metal horn);

e. In order to lead out, orient and twist the PLA nanofibrous web in step (c), an insulating plastic rod is placed in the center of the gathering device 2 (metal horn) in advance, and when the plastic rod is slowly pulled out in the horizontal direction , a hollow conical nanofibrous web will be formed, the top is adhered to the plastic rod, and the bottom is connected to the edge of the gathering device 2 (metal horn), and the conical top of the nanofibrous web is further drawn, and the fibers will be oriented and gathered into nanofiber bundles, and pre-twisted into PLA nanofiber strips with a certain twist through the rotation of the gathering device 2 (metal horn);

f. Connect the air inlet pipe 20 of the nozzle twister 4 with the air compressor, and the compressed air is injected into the yarn path 16 from the injection hole 15, forming a high-speed rotating airflow in the yarn path 16, and forming Negative pressure. The pre-twisted PLA nanofiber strips in step (d) are introduced into the bundler 3, and the PLA nanofiber strips are sucked into the yarn path 16 due to the negative pressure, twisted into yarns under the action of the swirling airflow and flow along the yarn path. 16. Output from the outlet pipe 18 through the intermediate pipe 17;

g. The PLA nanofiber yarn twisted in step (e) is output under the action of the yarn drawing roller 5, and is wound into a tube by the winding mechanism 6.

In this example, the rotation of the gathering device 2 (metal horn) can pre-twist the PLA nanofiber bundle. Therefore, the twisting of the PLA nanofiber yarn depends on the jet airflow in the nozzle twister 4 yarn path 16 The high-speed rotation and the rotation of the gathering device 2 are completed together.

Claims (8)

1. An air-jet spinning device for electrospinning nanofibers, characterized in that: it comprises a gathering device (2), two spinnerets (1) are arranged on both sides of the gatherer (2), two spinnerets (1) Connected to the high-voltage electrostatic generator (7), a cluster (3) is provided under the gathering device (2), and two spinning devices (1) are located between the gathering device (2) and the cluster (3), Arranged symmetrically along the axis, the nozzle twister (4) is installed under the bundler (3), the yarn delivery roller (5) is installed under the nozzle twister (4), and the winding roller (5) is installed under the yarn delivery roller (5). The mechanism (6), the gathering device (2), the buncher (3), the nozzle twister (4) and the yarn delivery roller (5) are arranged along the same axis from top to bottom. 2. The air-jet spinning device for electrospinning nanofibers according to claim 1, characterized in that: said spinning device (1) is composed of an air chamber (8) with an air inlet (11) on one side ) and a solution chamber (14) with a liquid inlet (12) on one side are connected through an intermediate connector (13). The intermediate connector (13) is provided with a vertically upward jet tube (10), and the solution chamber ( 14) is provided with a vertically upward spinneret (9). 3. The air-jet spinning device for electrospinning nanofibers according to claim 2, characterized in that: the air chamber (8) and the solution chamber (14) are cylindrical; the spinneret (9) and at least one jet tube (10), they are arranged in concentric circles, each spinneret (9) corresponds to a coaxial jet tube (10) for its ventilation, and the height of the jet tube (10) is lower than The upper surface of the spinneret (9) is higher than the upper surface of the solution chamber (14), the inner diameter of the spinneret (9) is 1-40mm, and the distance is 0.1-15cm. 4. The air-jet spinning device for electrospinning nanofibers according to claim 3, characterized in that: the gathering device (2) is a metal disc or horn with a rotating shaft, and its rotation is controlled by a transmission mechanism. The shaft rotates, and the diameter of the metal disc or bell mouth is 1-2 times the diameter of the upper surface of the solution chamber (14) in the spinning device (1); the diameter of the cluster (3) from the inlet to the outlet gradually narrows Trumpet-shaped, the diameter of the outlet is 0.8-8mm. 5. The air-jet spinning device for electrospinning nanofibers according to claim 4, characterized in that: the nozzle twister (4) consists of an air inlet pipe (20), an air chamber (19), and an injection hole ( 15), yarn path (16), intermediate pipe (17) and outlet pipe (18), the injection hole (15) is tangent to the inner circumference of the yarn path (16), and the diameter of the injection hole (15) is 0.1-0.55mm, the included angle with the yarn path (16) is 30-50°, and the number of spray holes is 2-8; the diameter of the yarn path (16) above the entrance of the spray hole (15) is 0.8- 2.0mm, 8-15mm in length, 2.0-3.5mm in diameter below the inlet of the injection hole (15), 8-15mm in length; the diameter of the intermediate pipe (17) is 3.0-6.0mm, and 8-15mm in length; The outlet pipe (18) has a diameter of 5.0-10.0mm and a length of 5-12mm. 6. The air-jet spinning device for electrospinning nanofibers according to claim 5, characterized in that: the angle between the spinning device (1) and the axis is 15-40°; the outlet of the cluster (3) Link to the entrance of the yarn path (16) in the nozzle twister (4); the distance between the upper end faces of the center spinnerets (9) of the two spinnerets (1) is 5-50cm, and the gathering device (2 ) between the center positions of 6-60cm; the distance between the entrance of the nozzle twister (4) yarn path (16) and the gathering device (2) is 15-100cm. 7. The air-jet spinning device for electrospinning nanofibers according to claim 6, characterized in that: the voltage of the high-voltage electrostatic generator (7) is 10-200kV, and the positive and negative electrodes are respectively connected to the two spinning wires The spinneret (9) made of metal in the device (1) is connected. 8. according to the method for preparing nanofiber yarn by the air-jet spinning device described in any one of claim 1～7, it is characterized in that, its steps are as follows: a. Use a peristaltic pump or other constant-speed liquid supply device to input the polymer spinning solution into the solution chamber through the liquid inlet (12) at a uniform speed. The liquid level of the spinning solution is lower than the upper surface of the spinneret (9), and the high on the upper end surface of the jet pipe (10); b. Use a cross-flow air pump or other uniform ventilation device to continuously output gas to the air chamber (8) through the air inlet (11), and the gas is sprayed upward through the air injection pipe (10), and the spinning solution is on the top of the spinneret (9) A hollow solution bulge is formed on the end face; c. Open the transmission mechanism of the accumulation device (2), the accumulation device (2) rotates around the shaft, and the control speed is 10-2000 rpm; d. Turn on the high-voltage electrostatic generator (7) and adjust it to a certain voltage. The positive and negative electrodes of the high-voltage electrostatic generator (7) are respectively connected to the metal spinnerets (9) in the two spinning devices (1) , the accumulation device (2) is not grounded, under the action of high-voltage electric field, the polarized charge gathers on the top of the spinneret (9) to form a Taylor cone, which is hollow under the action of airflow pressure and electrostatic force Breaking, the spinnerets (9) of the two spinneret devices (1) eject jets with opposite charges, and through electrostatic drawing, attraction and neutralization, the nanofibrous web is deposited on the edge of the agglomeration device (2); e. Lead out, orient and twist the nanofibrous web in step (c). An insulating plastic rod is placed in the center of the gathering device (2) in advance, and the plastic rod is slowly pulled out backwards along the horizontal direction to form a hollow cone. Shaped nanofibrous web, the top is adhered to the plastic rod, and the bottom end is connected with the edge of the gathering device (2), and the cone top of the nanofibrous web is further drawn, and the fibers are oriented and gathered into nanofiber bundles, or further passed through the gathering device (2) Rotating pre-twisted nanofiber strips with a certain twist; f. Connect the air inlet pipe (20) of the nozzle twister (4) to the air compressor, and the compressed air is injected into the yarn path (16) from the injection hole (15) to form a high-speed rotation in the yarn path (16). Air flow, and negative pressure is formed at the entrance of the yarn path (16), and the nanofiber bundle (or nanofiber strip) in step (d) is introduced into the bundler (3), and the nanofiber bundle is sucked into the yarn path due to the existence of negative pressure In (16), under the action of the rotating air flow, the yarn is twisted into yarn and output along the yarn path (16), through the intermediate pipe (17), and from the outlet pipe (18); g. The nanofiber yarn twisted in step (e) is output under the action of the yarn drawing roller (5), and wound into a tube by the winding mechanism (6).

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