Solution jet spinning nanofiber yarn forming device and preparation method

Abstract

The invention discloses a solution jet spinning nanofiber yarn forming device, and relates to the technical field of yarn, the solution jet spinning nanofiber yarn forming device comprises a nanofiber generating mechanism, a fiber bundle compounding mechanism and a yarn collecting mechanism which are arranged in sequence, the nanofiber generating mechanism can utilize airflow to stretch spinning solution trickles to obtain nanofiber bundles, and the nanofiber bundles are arranged on the spinning solution trickles. The fiber bundle compounding mechanism is arranged at the outlet end of the nanofiber generating mechanism, the fiber bundle compounding mechanism receives nanofiber bundles generated by the nanofiber generating mechanism and forms nanofiber yarns, and the yarn collecting mechanism is used for winding and collecting the nanofiber yarns. The invention further discloses a method for preparing the nanofiber yarn through the device. The nanofiber yarn prepared through the device and the method has the advantages of being small in size, large in specific surface area, high in porosity, good in orientation degree, large in tensile strength, fluffy in structure, capable of achieving large-scale production and the like.

Description

Technical Field

[0001] The invention relates to the technical field of yarn preparation, in particular to a solution jet spinning nanofiber yarn forming device and a preparation method. Background Art

[0002] Compared with electrospinning technology, solution jet spinning is one of the effective methods for large-scale preparation of nanofibers. Huangz et al. pointed out that solution jet spinning technology was first proposed by Medeiros as a method for preparing nanofibers by combining the characteristics of melt-blowing technology and dry spinning technology. The basic principle of this technology is to use high-speed airflow to ultra-finely stretch the solution stream, and solidify it into nanofibers accompanied by solvent evaporation. The fibers prepared by solution jet spinning technology are more fluffy, have low process energy consumption, high production efficiency (its single needle spinning speed can reach 10 times the speed of electrospinning), simple equipment, safe and flexible production operation, and are more suitable for industrial production.

[0003] The preparation of nanofiber yarn in the prior art includes the following two methods:

[0004] (1) The original mesh collector is replaced by a rotating disc, and the nanofibers are used to pull out oriented nanofiber yarns on the rotating disc.

[0005] (2) Based on the solution jet spinning device, a pair of parallel rollers were added as receiving devices to prepare oriented polyacrylonitrile (PAN) nanofiber yarns.

[0006] However, neither of the above two methods can solve the problem of large-scale continuous preparation of nanofiber yarns. Summary of the invention

[0007] The purpose of the present invention is to provide a solution jet spinning nanofiber yarn forming device and method to solve the technical problem that nanofiber yarn cannot be prepared continuously on a large scale in the prior art.

[0008] The present invention provides a solution jet spinning nanofiber yarn forming device, comprising a nanofiber generating mechanism, a fiber bundle composite mechanism and a yarn collecting mechanism, wherein the nanofiber generating mechanism can use an airflow to stretch a thin flow of spinning solution to obtain a nanofiber bundle, the fiber bundle composite mechanism is arranged at the outlet end of the nanofiber generating mechanism, the fiber bundle composite mechanism receives the nanofiber bundle generated by the nanofiber generating mechanism and forms a nanofiber yarn, and the yarn collecting mechanism is used to wind and collect the nanofiber yarn;

[0009] Among them, the fiber bundle composite mechanism includes a collecting section for forming an oriented nanofiber bundle and a twisting section for twisting the oriented nanofiber bundle to form an oriented nanofiber yarn. The collecting section is conical, and the large end of the collecting section faces the outlet end of the nanofiber generating mechanism, and the small end of the collecting section is connected to the twisting section.

[0010] Furthermore, the nanofiber generating machine includes a solution pushing pump, a first high-pressure gas cylinder and a coaxial needle, the axis of the coaxial needle coincides with the axis of the fiber bundle composite mechanism, the inner cavity of the coaxial needle is provided with a high-speed airflow channel and a spinning liquid extrusion channel, the high-speed airflow channel is arranged on the outer circle of the spinning liquid extrusion channel and is connected to the first high-pressure gas cylinder, and the spinning liquid extrusion channel is connected to the solution pushing pump.

[0011] Furthermore, it also includes a closed box, and the coaxial needle head, the fiber bundle composite mechanism and the yarn collecting mechanism are all arranged in the closed box.

[0012] Furthermore, an air blowing mechanism, a heating system and an exhaust gas treatment mechanism are arranged in the sealed box, and a monitoring mechanism for detecting the temperature and humidity of the inner cavity is arranged outside the sealed box.

[0013] Furthermore, the outer wall of the twisting section is evenly provided with a plurality of air flow holes along its circumferential direction, the air flow holes are arranged obliquely, the air inlet of the air flow holes is connected to a second high-pressure gas cylinder, and the angle between the axis of the air flow holes and the horizontal line is 30-45°.

[0014] Furthermore, the yarn collecting mechanism comprises a winding and collecting roller, and the winding and collecting roller is connected to an automatic deviation correcting mechanism for driving the winding and collecting roller to reciprocate along the axial direction.

[0015] Furthermore, a guide yarn is passed through the fiber bundle composite mechanism, and the fiber bundle composite mechanism receives the nanofibers generated by the nanofiber generating mechanism to form a nanofiber bundle and wraps the guide yarn to form a nanofiber yarn.

[0016] The present invention also provides a method for preparing nanofiber yarn using the solution jet spinning nanofiber yarn forming device, comprising the following steps:

[0017] S1, preparing spinning solution;

[0018] S2, introducing the spinning solution into the nanofiber generating mechanism, and using the airflow to stretch the spinning solution thin stream to obtain the nanofiber bundle;

[0019] S3, pushing the nanofiber bundle into the collecting section of the fiber bundle composite mechanism, and then using the twisting section to twist the nanofiber bundle to form nanofiber yarn and winding it on the yarn collecting mechanism.

[0020] Furthermore, in S3, it also includes: inserting a lead yarn inside the fiber bundle composite mechanism, winding one end of the lead yarn on the yarn collecting mechanism, and the nanofiber bundle entering the collecting section is wrapped on the lead yarn to form an inverted cone shape, and under the action of the twisting section, the nanofiber bundle and the lead yarn jointly form a nanofiber yarn

[0021] Further, in S1, preparing the spinning solution includes adding polyacrylonitrile to N,N-dimethylformamide, and continuously stirring to completely dissolve the polyacrylonitrile to obtain a polyacrylonitrile solution with a mass fraction of 6-15%.

[0022] Furthermore, the rate at which the spinning solution enters the nanofiber generating mechanism is 8-20 mL / h, the gas pressure of the first high-pressure gas cylinder in the nanofiber generating mechanism is 0.04±0.02 MPa, and the distance between the feed end of the fiber bundle composite mechanism and the discharge end of the nanofiber generating mechanism is 30±10 cm.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) The present invention utilizes a high-speed airflow to perform ultrafine stretching on a thin flow of solution. During the stretching process, the solvent evaporates to solidify the solute, and finally forms nanofibers. The conical structure of the collecting section in the fiber bundle composite mechanism helps to collect a large number of nanofibers. With the help of the high-speed airflow ejected by the nanofiber generating mechanism, the nanofibers are stretched along the inner wall of the yarn collecting device toward the yarn collecting mechanism, ensuring that the nanofibers are always maintained in a quantity that can be formed into yarns. The fibers are stretched under the action of the airflow, and twisted under the action of the airflow, so that the overall orientation of the fibers is better.

[0025] (2) The solution jet spinning device of the present invention is small in size and does not require cleaning, carding, drawing, roving, spinning and auxiliary equipment in the traditional spinning process;

[0026] (3) The nanofiber yarn prepared by the solution jet spinning nanofiber yarn forming device provided by the present invention has a larger specific surface area than the traditional yarn, and the fiber is nanometer-level with a diameter range of 500-4000nm; and the nanofiber yarn has a high porosity, which is reflected in the small diameter of the nanofiber. Under the condition of the same yarn count, the product of this project has more fiber roots, higher porosity between fibers, more fluffy yarn structure, and higher yarn strength; BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a solution jet spinning nanofiber yarn forming device provided in an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of the structure of a coaxial needle provided in an embodiment of the present invention;

[0030] Figure 3 A schematic cross-sectional view of a twisting section provided in an embodiment of the present invention.

[0031] Reference numerals:

[0032] 1. Solution push pump; 2. First high-pressure gas cylinder; 3. Second high-pressure gas cylinder; 4. Coaxial needle; 5. Fiber bundle composite mechanism; 6. Yarn collecting mechanism; 7. Sealed box; 8. Exhaust gas treatment mechanism;

[0033] 41. High-speed air flow channel; 42. Spinning solution extrusion channel;

[0034] 51. Air flow holes. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0036] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0037] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Combine the following Figures 1 to 3 As shown, an embodiment of the present invention provides a solution jet spinning nanofiber yarn forming device, including a nanofiber generating mechanism, a fiber bundle composite mechanism 5 and a yarn collecting mechanism 6 which are sequentially arranged along the drawing direction, wherein the nanofiber generating mechanism can utilize an airflow to stretch a fine flow of spinning solution to obtain a nanofiber bundle, and the fiber bundle composite mechanism 5 is arranged at an outlet end of the nanofiber generating mechanism, and the fiber bundle composite mechanism 5 receives the nanofiber bundle generated by the nanofiber generating mechanism and forms a nanofiber yarn, and the yarn collecting mechanism 6 is used for winding and collecting the nanofiber yarn, for example, the yarn collecting mechanism 6 can be a winding and collecting roller, and the winding and collecting roller is connected with an automatic deviation correction mechanism for driving it to move along the axial direction.

[0041] Among them, the fiber bundle composite mechanism 5 includes a collecting section for forming an oriented nanofiber bundle and a twisting section for twisting the oriented nanofiber bundle to form an oriented nanofiber yarn. The collecting section is conical, and the large end of the collecting section faces the outlet end of the nanofiber generating mechanism, and the small end of the collecting section is connected to the twisting section.

[0042] In some embodiments of the present invention, the nanofiber generating mechanism can use airflow to stretch the spinning solution flow to obtain nanofiber bundles. The ultrafine stretching means that the diameter of the nanofiber bundle after stretching is in the range of 10nm-30μm. Preferably, the airflow is a high-speed airflow.

[0043] Through the above-mentioned cone-shaped structure design with a width at the top and a narrowness at the bottom, the nanofibers are gradually gathered and twisted into yarns from the large-mouth end to the small-mouth end under the combined action of the blowing force of the airflow provided by the solution push pump 1 and the first high-pressure gas cylinder 2 and the pulling force of the yarn collecting mechanism 6. The opening direction is beneficial to the guidance of the airflow and the aggregation of the fibers, which can reduce the scrap rate of the nanofibers, thereby ensuring that the nanofibers are always maintained in a quantity that can be formed into yarns.

[0044] In the prior art, the fibers have no bonding points, and the fibers in the yarn are held together by twisting, which is a physical combination; after the spinning solution of the present invention is ejected from the coaxial needle, during the process to the fiber bundle composite mechanism 5, the solvent gradually evaporates and the fibers gradually solidify. When the fibers reach the fiber bundle composite mechanism 5, some of the fibers are bonded to each other. Therefore, there are two bonding modes between the fibers of the present invention, namely twisting and bonding and fiber bonding.

[0045] In some embodiments of the present invention, the nanofiber generating mechanism includes a solution push pump 1, a first high-pressure gas cylinder 2 and a coaxial needle 4, the axis of the coaxial needle 4 coincides with the axis of the fiber bundle composite mechanism 5, the inner cavity of the coaxial needle 4 is provided with a high-speed airflow channel 41 and a spinning liquid extrusion channel 42, the high-speed airflow channel 41 is arranged on the outer circle of the spinning liquid extrusion channel 42 and is connected to the first high-pressure gas cylinder 2, the spinning liquid extrusion channel 42 is connected to the solution push pump 1, the solution push pump 1 can be heated and stirred, the spinning liquid is extruded from the spinning liquid extrusion channel 42, and at the same time, a high-speed airflow passes through the high-speed airflow channel 41, and the high-speed airflow is used to perform ultra-fine stretching on the solution flow, and the solute is solidified during the stretching process accompanied by the evaporation of the solvent, thereby finally forming nanofibers.

[0046] The spinning solution of the present invention is ejected from the coaxial needle 4 under the synergistic effect of the solution push pump 1 and the airflow treatment of the first high-pressure gas cylinder 2, and the pushing and spraying of the spinning solution are separated. When used at the same time, they can play a synergistic role. The spinning solution is sprayed more evenly during the production process, and the solid content consistency during the spraying process is better.

[0047] When arranging the equipment specifically, taking into account the toxicity and polluting nature of the solvents of some products in the production process, which require exhaust gas recovery or treatment, in some embodiments of the present invention, the coaxial needle 4, the fiber bundle composite mechanism 5 and the yarn collecting mechanism 6 are all arranged in the closed box 7, and the closed box 7 is provided with a blowing mechanism, a heating system and an exhaust gas treatment mechanism 8. The blowing mechanism mainly acts on the exhaust gas treatment mechanism 8 for exhausting the exhaust gas.

[0048] In addition, temperature and humidity will affect the curing speed and crystallinity of the fiber during the production process. In order to ensure the quality of the product, the temperature and humidity in the box need to be controlled. Therefore, a monitoring mechanism for detecting the temperature and humidity of the inner cavity is provided on the outside of the closed box 7. The specific temperature and humidity monitoring range is determined according to the actual product properties. The principle of setting is: within this numerical range, the fiber curing rate is high, the product quality is good, and the production cost is low. Outside this numerical range, it will affect the product quality and increase the production cost. In the embodiment of the present invention, preferably, the temperature is controlled at 20-40°C and the humidity is controlled at 20%-40%.

[0049] In addition, the outer wall of the twisting section is evenly provided with a plurality of air flow holes 51 along its circumferential direction. The air flow holes 51 are inclined and the air inlet of the air flow holes 51 is connected to a second high-pressure gas cylinder 3. When the oriented nanofiber bundle passes through the twisting section at a certain speed, the pressure and angle of the tangential airflow can be changed to adjust the diameter and twist of the nanofiber yarn.

[0050] The angle between the axis of the air flow hole 51 and the horizontal line is designed to be 30-45°. If the angle is too large, the fiber twist will be too large, and the softness of the yarn will be reduced. If the angle is too small, the fiber twist will be too low, the yarn will have more hairiness and lower strength. The diameter of the nanofiber yarn is 500-4000nm, so that the fiber has better cohesion, high yarn strength and less hairiness. Especially when producing core-spun yarn, the yarn has good wrapping properties and the nanofibers are arranged in an orderly manner, so that the mechanical properties of the nanofiber yarn are effectively improved.

[0051] In some embodiments of the present invention, a guide yarn is inserted into the fiber bundle composite mechanism 5, and the fiber bundle composite mechanism 5 receives the nanofibers generated by the nanofiber generating mechanism to form a nanofiber bundle and wraps the guide yarn to form a nanofiber yarn.

[0052] The present invention also provides a method for preparing nanofiber yarn using the solution jet spinning nanofiber yarn forming device, comprising the following steps:

[0053] Step 100, preparing a spinning solution;

[0054] Specifically, due to the high mass fraction of the spinning solution, the viscosity of the spinning solution is too high, the fluidity is poor, the diameter of the nanofiber is large, and the fiber diameter CV value is large. If the mass fraction is too low, the solid content of the spinning solution is low, the strength of the sprayed fiber is low, and the fiber solidification is slow. Therefore, preferably, the mass fraction of polyacrylonitrile (PAN) is 6-15%, and the solvent is DMF (N,N-dimethylformamide). During the dissolution process, continuous stirring is required until PAN is completely dissolved. Preferably, it is heated to 40°C and stirred for 1-3 hours until PAN is completely dissolved.

[0055] Step 200, the spinning solution is introduced into the coaxial needle 4 in the nanofiber generating mechanism, and the DMF in the spinning solution is rapidly evaporated under the traction of the high-pressure airflow provided by the solution push pump 1 and the first high-pressure gas cylinder 2, and the PAN is rapidly solidified to form a colloidal short fiber bundle. Due to the traction of the high-pressure airflow provided by the first high-pressure gas cylinder 2, the colloidal fiber bundle is rapidly pulled and stretched, and the colloidal fiber is secondary solidified to form PAN nanofibers, and finally a solidified nanofiber bundle is formed;

[0056] In the subsequent process of forming nanofiber yarn, the nanofiber bundle can be formed individually or in the form of a core-spun yarn, that is, a lead yarn is provided to cover the nanofiber bundle on the outside of the lead yarn.

[0057] When forming separately, specifically, step 300 includes:

[0058] The nanofiber bundle is pushed into the collecting section of the fiber bundle composite mechanism 5, and then the nanofiber bundle is twisted by the twisting section to form nanofiber yarn and wound on the yarn collecting mechanism 6. The rolling collecting roller pulls the wound nanofiber yarn downward and slides up and down to evenly collect the nanofiber yarn on the rolling collecting roller.

[0059] When producing nanofiber yarn in the form of core-spun yarn, in step 300, it also includes: inserting a lead yarn into the interior of the fiber bundle composite mechanism 5, winding one end of the lead yarn around the yarn collecting mechanism 5, and the nanofiber bundle entering the collecting section is wrapped around the lead yarn and forms an inverted cone shape, and under the action of the twisting section, the nanofiber bundle and the lead yarn together form a nanofiber yarn.

[0060] In the above process, the material of the yarn can be freely selected as needed, the rate at which the spinning solution enters the nanofiber generating mechanism is 8-20mL / h, and the air pressure of the first high-pressure gas cylinder 2 in the nanofiber generating mechanism also needs to be reasonably set. This is because excessive air pressure causes the fibers to be blown away during molding, the fiber length is reduced, and the length distribution is more discrete, which reduces the yarn strength. If the air pressure is too low, the proportion of fibers reaching the fiber bundle composite mechanism 5 will be low, reducing the effective utilization rate of the fibers and increasing the production cost. In addition, the time for the fibers to reach the fiber bundle composite mechanism 5 is long, causing some fibers to solidify before reaching the fiber bundle composite mechanism 5, affecting the strength of the yarn. Therefore, it is preferred that the air pressure of the first high-pressure gas cylinder 2 is 0.04±0.02MPa.

[0061] At the same time, a distance between the feed end of the fiber bundle composite mechanism 5 and the discharge end of the nanofiber generating mechanism that is too short is not conducive to the effective stretching of the fibers, and a distance that is too long will cause some fibers to solidify prematurely, affecting the bonding between the fibers in the yarn and reducing the yarn strength. Therefore, it is preferably 30±10 cm.

[0062] The nanofiber yarn prepared by the above method has the characteristics of small size, large specific surface area, high porosity, good orientation, high tensile strength, fluffy structure, and can be mass-produced. First, the nanofiber yarn is composed of nanofibers, which will maintain the original advantage of large specific surface area of ​​nanofibers. The yarn production device is simple, efficient, and low-cost, which is conducive to industrial production; secondly, the nano yarn overcomes the disadvantage of weak mechanical properties of traditional nanofiber membranes. The length CV value of the fiber prepared by the present invention is lower, the fiber bonding strength between the yarns is high, the yarn strength is high, and it can be further woven, composited, and functionalized. It can be made into various structural materials, composite materials, special functional materials, and weaving two-dimensional or three-dimensional fabrics of different structures, realizing the transformation of nanomaterials such as irregular or oriented nanofibers into macroscopic materials, which can improve the functional stability of the material and the service life of the prepared material.

[0063] The present application is described below through specific embodiments.

[0064] Embodiment 1:

[0065] 150 g of polyacrylonitrile (PAN) and 850 g of DMF (N,N-dimethylformamide) were mixed, heated to 40° C., and stirred for 2 h until PAN was completely dissolved.

[0066] The spinning solution feeding rate is 12 ml / h, and the gas pressure of the first high-pressure gas cylinder is 0.05 MPa.

[0067] The yarn collection rate was 1 m / min.

[0068] Embodiment 2:

[0069] 100 g of polyacrylonitrile (PAN) and 900 g of DMF (N,N-dimethylformamide) were mixed, heated to 40° C., and stirred for 2 h until PAN was completely dissolved.

[0070] The spinning solution feeding rate is 10ml / h, and the pressure of the first high-pressure gas cylinder is 0.05MPa. At the same time, 150D / 72f polyester filament is fed into the middle of the fiber bundle collection mechanism.

[0071] The feeding speed and yarn collection rate of the polyester filament were 0.8 m / min.

[0072] Embodiment 3:

[0073] 60 g of polyacrylonitrile (PAN) and 940 g of DMF (N,N-dimethylformamide) were mixed, heated to 40° C., and stirred for 2 h until PAN was completely dissolved.

[0074] The spinning solution feeding rate is 14 ml / h, and the gas pressure of the first high-pressure gas cylinder is 0.05 MPa. At the same time, a stainless steel wire with a diameter of 30 μm is fed into the middle of the fiber bundle collecting mechanism.

[0075] The feeding speed of the stainless steel wire and the yarn collection rate were 0.8 m / min.

[0076] Embodiment 4:

[0077] 150 g of polyacrylonitrile (PAN) and 850 g of DMF (N,N-dimethylformamide) were mixed, heated to 40° C., and stirred for 2 h until PAN was completely dissolved.

[0078] The spinning solution feeding rate is 12ml / h, and the pressure of the first high-pressure gas cylinder is 0.05MPa. At the same time, 40D spandex filament is fed into the middle of the fiber bundle collection mechanism.

[0079] The feeding speed of the spandex filament was 0.4 m / min and the yarn collection rate was 0.8 m / min.

[0080] The fineness and product performance of the composite yarn obtained in the above Examples 1-4 are shown in Table 1:

[0081] Table 1

[0082]

[0083]

[0084] Among them, Examples 1-3 do not contain spandex, and the tensile properties of the yarn will have data related to breaking strength, initial modulus, and breaking elongation. However, Example 4 contains spandex, and the yarn mainly plays an elastic role. There will be pull data, but the initial modulus data has not been evaluated.

[0085] The excellent performance of the composite yarn prepared in the embodiment of the present invention is mainly reflected in:

[0086] 1) Taking Example 1 as an example, due to the bonding points between the fibers, the breaking strength of the yarn is 2.63cn / dtex, which is 38-163% higher than that of the traditional yarn (1.0-1.9cn / dtex); in addition, taking Example 3 as an example, when combined with 30μm stainless steel wire, an ultra-high breaking strength can be achieved, which is far higher than that of the traditional core-spun yarn.

[0087] 2) Taking Example 2 as an example, a 16s core-spun yarn with a core wire of 150D is made using the traditional core-spun process. The surface area of ​​the core wire exposed is about 15. The core wire of Example 2 has good wrapping properties and there is no problem of core wire leakage (the surface area of ​​the core wire leakage is less than 1%). Therefore, this process can solve the industry problem of core wire leakage; the fiber diameter is 500-800nm, and the fiber diameter is at the nanometer level. Compared with traditional yarns, when the yarn fineness is the same, the nanofiber yarn of Example 2 has more fibers in the cross section, so it has better wrapping properties.

[0088] 3) Taking Example 4 as an example, due to the bonding points between the fibers, when combined with spandex, the washing shrinkage of the fabric is 30-50% smaller than that of traditional fabrics.

[0089] 4) The diameter of the fiber is small, at the nanometer level, and the fiber diameter ranges from 500-4000nm. Under the condition of the same yarn count, the yarn has more fibers in the cross section than ordinary yarn, a larger specific surface area, a high porosity, a fluffy yarn structure, good yarn softness, and a high wearing comfort of the fabric.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solution jet spinning nanofiber yarn forming device, characterized in that: The invention comprises a nanofiber generating mechanism, a fiber bundle composite mechanism (5) and a yarn collecting mechanism (6), wherein the nanofiber generating mechanism is capable of using an airflow to stretch a thin flow of spinning liquid to obtain a nanofiber bundle, the fiber bundle composite mechanism (5) is arranged at the outlet end of the nanofiber generating mechanism, the fiber bundle composite mechanism (5) receives the nanofiber bundle generated by the nanofiber generating mechanism and forms nanofiber yarn, and the yarn collecting mechanism (6) is used to wind and collect the nanofiber yarn; The fiber bundle composite mechanism (5) comprises a collecting section for forming an oriented nanofiber bundle and a twisting section for twisting the oriented nanofiber bundle to form an oriented nanofiber yarn, wherein the collecting section is in a conical shape, and the large end of the collecting section faces the outlet end of the nanofiber generating mechanism, and the small end of the collecting section is connected to the twisting section.

2. The solution jet spinning nanofiber yarn forming device according to claim 1, characterized in that: The nanofiber generating machine comprises a solution push pump (1), a first high-pressure gas cylinder (2) and a coaxial needle (4); the axis of the coaxial needle (4) coincides with the axis of the fiber bundle composite mechanism (5); the inner cavity of the coaxial needle (4) is provided with a high-speed airflow channel (41) and a spinning liquid extrusion channel (42); the high-speed airflow channel (41) is arranged on the outer ring of the spinning liquid extrusion channel (42) and is connected to the first high-pressure gas cylinder (2); and the spinning liquid extrusion channel (42) is connected to the solution push pump (1).

3. The solution jet spinning nanofiber yarn forming device according to claim 2, characterized in that: It also comprises a sealed box (7), wherein the coaxial needle head (4), the fiber bundle composite mechanism (5) and the yarn collecting mechanism (6) are all arranged in the sealed box (7).

4. The solution jet spinning nanofiber yarn forming device according to claim 3, characterized in that: The sealed box (7) is provided with an air blowing mechanism, a heating system and an exhaust gas treatment mechanism (8), and a monitoring mechanism for detecting the temperature and humidity of the inner cavity of the sealed box (7) is provided outside the sealed box (7).

5. The solution jet spinning nanofiber yarn forming device according to claim 2, characterized in that: The outer wall of the twisting section is evenly provided with a plurality of air flow holes (51) along its circumferential direction, the air flow holes (51) are arranged obliquely, the air inlet of the air flow hole (51) is connected to the second high-pressure gas cylinder (3), and the angle between the axis of the air flow hole (51) and the horizontal line is 30-45°.

6. The solution jet spinning nanofiber yarn forming device according to claim 1, characterized in that: The yarn collecting mechanism (6) comprises a winding and collecting roller, and the winding and collecting roller is connected to an automatic deviation correcting mechanism for driving the winding and collecting roller to move back and forth along the axial direction.

7. The solution jet spinning nanofiber yarn forming device according to claim 1, characterized in that: The fiber bundle composite mechanism (5) is provided with a guide yarn passing through it. The fiber bundle composite mechanism (5) receives the nanofibers generated by the nanofiber generating mechanism to form a nanofiber bundle and wraps it on the guide yarn to form a nanofiber yarn.

8. A method for preparing nanofiber yarn using the solution jet spinning nanofiber yarn forming device according to any one of claims 1 to 7, characterized in that: The steps include: S1, preparing spinning solution; S2, introducing the spinning solution into the nanofiber generating mechanism, and using the airflow to stretch the spinning solution thin stream to obtain the nanofiber bundle; S3, pushing the nanofiber bundle into the collecting section of the fiber bundle composite mechanism (5), and then using the twisting section to twist the nanofiber bundle to form nanofiber yarn and winding it on the yarn collecting mechanism (6).

9. The method for preparing nanofiber yarn according to claim 8, characterized in that: In S3, it also includes: inserting a lead yarn inside the fiber bundle composite mechanism (5), winding one end of the lead yarn around the yarn collecting mechanism (5), and the nanofiber bundle entering the collecting section is wrapped around the lead yarn and forms an inverted cone shape. Under the action of the twisting section, the nanofiber bundle and the lead yarn jointly form a nanofiber yarn.

10. The method for preparing nanofiber yarn according to claim 8, characterized in that: In S1, the step of preparing the spinning solution includes: adding polyacrylonitrile to N,N-dimethylformamide, and continuously stirring to completely dissolve the polyacrylonitrile to obtain a polyacrylonitrile solution with a mass fraction of 6-15%; Preferably, in step S2, the rate at which the spinning solution enters the nanofiber generating mechanism is 8-20 mL / h, the gas pressure of the first high-pressure gas cylinder (2) in the nanofiber generating mechanism is 0.04±0.02 MPa, and the distance between the feed end of the fiber bundle composite mechanism (5) and the discharge end of the nanofiber generating mechanism is 30±10 cm.

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