Liquid spray nanofiber on-line yarn forming method and nanofiber

Abstract

The present application relates to the field of liquid spray spinning, to solve the problem that the prior art is difficult to ensure that the thickness of the finished fiber meets the expectation while controlling the diameter of the finished fiber, and provides a liquid spray nanofiber online yarn forming method, comprising: S1, a metal cylinder is arranged between a spinning nozzle and a receiving plate, the metal cylinder is connected with an electrostatic generator; after the spinning liquid is sprayed from the spinning nozzle, it passes through the metal cylinder under the pulling of high-speed airflow, and finally deposits on the receiving plate; S2, a high-speed camera is arranged above the receiving plate, and the image of the deposited fiber on the receiving plate is collected by the high-speed camera; S3, the distance between the metal cylinder and the spinning nozzle is adjusted according to the characteristic information of the image until the characteristic information meets the preset value, and the characteristic information at least includes fiber diameter information. The metal cylinder in the present application has two functions, one is to add a charged metal cylinder on the basis of liquid spray spinning, and to further refine the fiber by using electrostatic force while using air flow to pull the spinning liquid jet. The second is to adjust the range of the electrostatic field by moving the metal cylinder, so as to adjust the diameter of the finished fiber.

Description

Technical Field

[0001] This invention relates to the field of liquid jet spinning, and more specifically, to a method for online yarn formation of liquid jet nanofibers and nanofibers. Background Technology

[0002] Jet spinning is a spinning method that uses a high-speed hot air stream to directly blow and stretch a polymer solution or melt extruded from a spinneret into fibers. Jet spinning is divided into solution spinning and melt spinning. In solution spinning, the polymer is dissolved in a volatile solvent to create a spinning solution. While the solution is being extruded from the spinneret, it is blown by a high-speed hot air stream, stretching the solution stream and simultaneously causing the solvent to evaporate and solidify, collecting on a web to form short fibers, nonwoven fabric, or long filament bundles. In melt spinning, polymer chips are melted and quantitatively extruded using a spinning screw extruder. Simultaneously, the melt is blown by a high-speed hot air stream to form fibers; this method is also known as meltblown spinning.

[0003] Because the diameter requirements for nanofibers vary depending on the application scenario, controlling the diameter of the finished fiber is one of the most pressing problems to be solved in liquid jet spinning technology. Patent CN103645751A discloses a method and device for controlling nanofiber diameter based on substrate speed adjustment. This method achieves closed-loop control through substrate speed to stabilize the nanofiber diameter, overcoming the instability of nanofiber diameter due to external parameters in existing nano-electrostatic inkjet printing technology. However, substrate speed determines the deposition time of the fiber at the same location on the substrate, thus affecting the nanofiber thickness. In other words, while ensuring the fiber diameter meets expectations, it is difficult to ensure that the thickness of the finished fiber also meets expectations. Summary of the Invention

[0004] The purpose of this invention is to provide a liquid-jet nanofiber online yarn forming method, which solves the problem that the existing technology cannot ensure that the thickness of the finished fiber also meets the expectations while controlling the diameter of the finished fiber;

[0005] Another objective of this invention is to provide a nanofiber that has the advantages of high porosity and good uniformity.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] A method for online spinning of liquid-jet nanofibers includes:

[0008] S1. A metal cylinder is installed between the spinning die and the receiving plate, and the metal cylinder is connected to the electrostatic generator; after the spinning solution is sprayed out from the spinning die, it passes through the metal cylinder under the pull of the high-speed airflow and finally deposits on the receiving plate.

[0009] S2, a high-speed camera is arranged above the receiving plate, and an image of the deposited fibers on the receiving plate is collected by the high-speed camera;

[0010] S3, the distance between the metal cylinder and the spinning die is adjusted according to the characteristic information of the image until the characteristic information meets the preset value, and the characteristic information at least includes fiber diameter information.

[0011] The application adds a charged metal cylinder on the basis of liquid spray spinning, and utilizes the electrostatic field to further refine the fibers while utilizing the air flow to pull the jet of spinning solution. The range of the electrostatic field is adjusted by moving the metal cylinder, so as to adjust the diameter of the finished fibers. The electrostatic generator charges the metal cylinder, so as to generate an electrostatic field. Under the action of the electrostatic field, each jet of spinning solution is charged with the same kind of charge, and the jets are further broken and refined under the action of repulsion. The preset value can be set according to the production needs.

[0012] Preferably, the S3 includes:

[0013] S31, the movement area of the jet of spinning solution is sequentially divided into an adjusting zone, a disturbance zone and a stable zone along the movement direction; the jet of spinning solution is heated in the adjusting zone, and the solvent volatilizes, so that the jet of spinning solution reaches the overlapping concentration; the jet of spinning solution is intertwined, curved and refined in the disturbance zone; the jet of spinning solution is solidified into a yarn before entering the stable zone, and the receiving plate is located in the stable zone;

[0014] S32, the metal cylinder moves in the disturbance zone.

[0015] Although the liquid spray spinning can further reduce the fiber diameter and has better uniformity compared with the melt blowing spinning, the liquid spray spinning needs to dissolve the raw material in the solvent, and the solubility of the raw material will affect whether the liquid spray spinning can be applied and the concentration of the spinning solution, and the concentration of the spinning solution is the primary condition for the jet of spinning solution to form fibers. The overlapping concentration is the critical concentration for the jet of spinning solution to form fibers. In the adjusting zone, the jet of spinning solution cannot form fibers stably, so the moving range of the metal cylinder in the application is outside the adjusting zone. The jet in the disturbance zone is refined under the action of the air flow and the electrostatic field. The application keeps the action distance of the air flow unchanged, and adjusts the action position of the electrostatic field. Even if the range of the electrostatic field is unchanged, when the position of the electrostatic field is changed, the diameter of the finished fibers can be adjusted.

[0016] Preferably, the S32 specifically includes: when the fiber diameter information is greater than the preset value, the metal cylinder moves towards the adjusting zone; and when the fiber diameter information is less than the preset value, the metal cylinder moves towards the stable zone.

[0017] When the fiber diameter is large, the metal cylinder moves towards the adjusting zone, so that the influence of the electrostatic field on the jet of spinning solution is advanced, thereby reducing the fiber diameter. The main mechanism is as follows:

[0018] The influence range of the electrostatic field does not change, only the influence is advanced, which can accelerate the breakup of the jet. When the jet is just out of the spinneret, the jet diameter is large, which can resist the bending disturbance caused by the air flow, and gradually thins mainly through the axial stretching of the surrounding air flow, and if the effect of the electrostatic field is advanced, the bending disturbance on the jet in the initial stage is increased, so that the jet breaks up earlier, that is, the jet breaks up when the jet diameter is large, compared with the case where the electrostatic field is applied after the jet has broken up, the electrostatic field also plays a certain role in the initial breakup, and the instantaneous force required by the jet at the moment of the first breakup is greater than that in the subsequent stage. If the instantaneous force is only provided by the air flow, the electrostatic field only plays a role in the further thinning of the jet after the breakup, and the applicant finds that the force required for the jet to be thinned to a certain diameter and the action time increase with the decrease of the diameter, and if the jet is further thinned after being thinned to a certain diameter, the uniformity of the fiber will also be greatly reduced, so the thinning efficiency of the electrostatic field in the region after the breakup is lower than that in the region before the breakup. The electrostatic field mainly increases the radial force on the jet, and the air flow increases the axial force, so that the radial force on the jet is reduced by withdrawing the electrostatic field in advance, and the uniformity of the finished fiber can be improved, and on the premise that the uniformity meets the requirement that it does not need to be improved any more, the action distance of the air flow can also be increased, so that the fiber can be further thinned.

[0019] On the contrary, if the fiber diameter is small, the metal cylinder is moved towards the stable zone, the initial breakup of the jet can be delayed, and the thinning efficiency of the electrostatic field as a whole is reduced.

[0020] Preferably, the farthest distance between the disturbance zone and the spinneret outlet is S, and the closest distance between the disturbance zone and the spinneret outlet is 2 / 13S-3 / 10S.

[0021] Through experiments, it is found that the closest distance between the disturbance zone and the spinneret outlet is best in the range of 2 / 13S-3 / 10S, if the distance is too close, the spinning solution may enter the metal cylinder before reaching the overlap concentration, reducing the effective utilization rate of the electrostatic field. If the distance is too far, the action time of the electrostatic field is too late, and the thinning efficiency is reduced.

[0022] Preferably, the base length of the metal cylinder is 1 / 3S-3 / 5S.

[0023] Through experiments, it is found that the best base length of the metal cylinder is 1 / 3S-3 / 5S, which can meet a wider range of fiber diameter regulation, and the porosity and uniformity of the finished product are also higher.

[0024] Preferably, the collection of the fiber diameter information comprises:

[0025] D1, the image collected by the high-speed camera is divided into an overlapping area and a non-overlapping area, the overlapping area refers to the area between the jet flows of the adjacent spinneret holes, and the fibers in the non-overlapping area are deposited by the jet flow of the spinning solution ejected from a single spinneret hole;

[0026] D2, the collection object of the fiber diameter information includes the fiber image in the overlapping area and the fiber image in the non-overlapping area.

[0027] Preferably, the fiber diameter information includes the fiber diameter size and the fiber diameter deviation n, wherein the fiber diameter in the non-overlapping area is d1, the fiber diameter in the overlapping area is d2, and n = |d1-d2| / d1.

[0028] The fibers produced by the adjacent spinneret holes will be partially overlapped and disturbed before solidification, and the diameters of the fibers in this part may be different from the diameters of the fibers in the non-overlapping area. In order to avoid such disturbance, the distance between the spinneret holes can be increased, but the production efficiency will also be reduced simultaneously. Therefore, the present application increases the analysis of the fiber diameter deviation when analyzing the fiber image, so as to ensure the uniformity of the finished product while ensuring that the fiber diameter is within the preset range, and thus the distance between the spinneret holes can be smaller than that in the conventional technology.

[0029] Preferably, the metal cylinder is a telescopic cylinder, and when the distance between the metal cylinder and the spinning die cannot be adjusted to make the characteristic information meet the preset value, the length of the metal cylinder is adjusted.

[0030] The structure of the telescopic cylinder can refer to that of the telescopic rod, and the telescopic cylinder is realized by the relative sliding of the inner and outer cylinders. If the expected product cannot be obtained by adjusting the position of the metal cylinder, the length of the metal cylinder can also be adjusted to control the range of the electrostatic field.

[0031] Preferably, when the fiber diameter information is greater than the preset value, the length of the metal cylinder is increased; and when the fiber diameter information is less than the preset value, the length of the metal cylinder is decreased.

[0032] When the fiber diameter is large, increasing the length of the metal cylinder can increase the time of the jet flow subjected to the electric field force, and improve the degree of splitting and thinning, and vice versa, the length of the metal cylinder is decreased, so as to avoid excessive thinning of the fibers.

[0033] A nanofiber produced by the online nanofiber yarn forming method.

[0034] The present application has at least the following beneficial effects:

[0035] The metal cylinder in this invention has two functions: first, by adding a charged metal cylinder to the liquid-jet spinning process, it utilizes airflow to pull the spinning liquid jet while simultaneously using electrostatics to further refine the fibers; second, by moving the metal cylinder, the position of the electrostatic field can be adjusted, thereby controlling the diameter of the finished fiber. The electrostatic generator charges the metal cylinder, generating an electrostatic field. Under the influence of this field, the various spinning liquid jets carry the same charge, and the repulsive force further splits and refines the jets. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of an online yarn-forming method for liquid-jet nanofibers;

[0038] Figure 2 A schematic diagram of the spinning solution jet and airflow near the spinneret;

[0039] Figure 3 A schematic diagram showing the overlapping and non-overlapping areas;

[0040] Figure 4 This is a schematic diagram of the partitioning of a fiber image;

[0041] Figure 5 The image shows the fiber morphology of product 1.

[0042] Figure 6 The image shows the fiber morphology of product 2.

[0043] Figure 7 The image shows the fiber morphology of product 3.

[0044] Figure 8 The image shows the fiber morphology of product 4.

[0045] Figure 9 The image shows the fiber morphology of product 5.

[0046] Icons: 1-Receiver plate, 2-Metal cylinder, 3-Electrostatic generator, 4-Spinneret, 5-High-speed camera, 6-Jet, 7-Airflow, 8-Adjustment zone, 9-Disturbance zone, 10-Stable zone, 11-Overlapping zone, 12-Non-overlapping zone. Detailed Implementation

[0047] To make the objectives, methods, and advantages of the embodiments of the present invention clearer, the method solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0048] Example 1

[0049] A method for online spinning of liquid-jet nanofibers includes:

[0050] S1, such as Figures 1-2 As shown, a metal cylinder 2 is placed between the spinning die and the receiving plate 1, and the metal cylinder 2 is connected to the electrostatic generator 3. After the spinning solution is sprayed out from the spinning die, it is pulled by the high-speed airflow 7, passes through the metal cylinder 2, and finally deposits on the receiving plate 1, which is grounded. The basic length of the metal cylinder 2 is 1 / 3S. The basic length refers to the initial length of the metal cylinder 2, that is, the length of the metal cylinder 2 before any length change. S is 25cm.

[0051] The high-speed airflow 7 adopts an annular airflow 7, and the spinning solution jet 6 is located in the middle of the annular airflow 7. The metal cylinder 2 is made of copper-aluminum alloy.

[0052] S2. A high-speed camera 5 is set above the receiving plate 1 to acquire images of the fibers deposited on the receiving plate 1.

[0053] S3. Adjust the distance between the metal cylinder 2 and the spinning die head according to the feature information of the image until the feature information meets the preset value. The feature information includes at least the fiber diameter information. The preset diameter value is 2μm.

[0054] The acquisition of the fiber diameter information includes:

[0055] D1, as Figures 3-4 As shown, the image acquired by the high-speed camera 5 is divided into an overlapping area 11 and a non-overlapping area 1211. The overlapping area 11 refers to the area between the spinning liquid jets 6 ejected from adjacent spinnerets 4. The fibers in the non-overlapping area 1211 are refined and deposited from the spinning liquid jets 6 ejected from a single spinneret 4.

[0056] D2. The fiber diameter information is collected from the fiber images in the overlapping area 11 and the fiber images in the non-overlapping area 1211.

[0057] The fiber diameter information includes: fiber diameter size and fiber diameter deviation n. Let the fiber diameter of the non-overlapping region 1211 be d1 and the fiber diameter of the overlapping region 11 be d2, and n = |d1-d2| / d1.

[0058] The image captured by the high-speed camera 5 is proportionally scaled to the actual image. Based on the scale, the actual fiber diameter can be calculated from the fiber width in the image. To make the diameter data more accurate, multiple fibers can be selected in the overlapping area 11 and the non-overlapping area 1211 to calculate the average diameter, thus obtaining d1 and d2.

[0059] S3 includes:

[0060] S31. The movement area of ​​the spinning solution jet 6 is sequentially divided into an adjustment zone 8, a disturbance zone 9, and a stabilization zone 10 along the movement direction. The spinning solution jet 6 is heated in the adjustment zone 8, the solvent evaporates, and the spinning solution reaches the overlapping concentration. The spinning solution jet 6 is entangled, bent, and refined in the disturbance zone 9. The spinning solution jet 6 is solidified into yarn before entering the stabilization zone 10, and the receiving plate 1 is located in the stabilization zone 10. Let the farthest distance between the disturbance zone 9 and the spinning die outlet be S, and the closest distance between the disturbance zone 9 and the spinning die outlet be 2 / 13S.

[0061] S32. The metal cylinder 2 moves within the disturbance zone 9. When the fiber diameter information is greater than the preset value, the metal cylinder 2 moves toward the adjustment zone 8; when the fiber diameter information is less than the preset value, the metal cylinder 2 moves toward the stabilization zone 10.

[0062] In this embodiment, the metal cylinder 2 is a telescopic cylinder. When adjusting the distance between the metal cylinder 2 and the spinning die head fails to make the feature information meet the preset value, the length of the metal cylinder 2 is adjusted. When the fiber diameter information is greater than the preset value, the length of the metal cylinder 2 is increased; when the fiber diameter information is less than the preset value, the length of the metal cylinder 2 is decreased.

[0063] Example 2

[0064] A method for online spinning of liquid-jet nanofibers includes:

[0065] S1, such as Figures 1-2 As shown, a metal cylinder 2 is placed between the spinning die and the receiving plate 1, and the metal cylinder 2 is connected to the electrostatic generator 3. After the spinning solution is sprayed out from the spinning die, it is pulled through the metal cylinder 2 by the high-speed airflow 7 and finally deposited on the receiving plate 1, which is grounded. The basic length of the metal cylinder 2 is 3 / 5S. The basic length refers to the initial length of the metal cylinder 2, that is, the length of the metal cylinder 2 before any length change. S is 25cm.

[0066] The high-speed airflow 7 adopts an annular airflow 7, and the spinning solution jet 6 is located in the middle of the annular airflow 7. The metal cylinder 2 is made of copper-aluminum alloy.

[0067] S2. A high-speed camera 5 is set above the receiving plate 1 to acquire images of the fibers deposited on the receiving plate 1.

[0068] S3. Adjust the distance between the metal cylinder 2 and the spinning die head according to the feature information of the image until the feature information meets the preset value. The feature information includes at least the fiber diameter information. The preset diameter value is 2μm.

[0069] The acquisition of the fiber diameter information includes:

[0070] D1, as Figures 3-4 As shown, the image acquired by the high-speed camera 5 is divided into an overlapping area 11 and a non-overlapping area 1211. The overlapping area 11 refers to the area between the spinning liquid jets 6 ejected from adjacent spinnerets 4. The fibers in the non-overlapping area 1211 are refined and deposited from the spinning liquid jets 6 ejected from a single spinneret 4.

[0071] D2. The fiber diameter information is collected from the fiber images in the overlapping area 11 and the fiber images in the non-overlapping area 1211.

[0072] The fiber diameter information includes: fiber diameter size and fiber diameter deviation n. Let the fiber diameter of the non-overlapping region 1211 be d1 and the fiber diameter of the overlapping region 11 be d2, and n = |d1-d2| / d1.

[0073] S3 includes:

[0074] S31. The movement area of ​​the spinning solution jet 6 is sequentially divided into an adjustment zone 8, a disturbance zone 9, and a stabilization zone 10 along the movement direction. The spinning solution jet 6 is heated in the adjustment zone 8, the solvent evaporates, and the spinning solution reaches the overlapping concentration. The spinning solution jet 6 is entangled, bent, and refined in the disturbance zone 9. The spinning solution jet 6 is solidified into yarn before entering the stabilization zone 10, and the receiving plate 1 is located in the stabilization zone 10. Let the farthest distance between the disturbance zone 9 and the spinning die outlet be S, and the closest distance between the disturbance zone 9 and the spinning die outlet be 2 / 13S.

[0075] S32. The metal cylinder 2 moves within the disturbance zone 9. When the fiber diameter information is greater than the preset value, the metal cylinder 2 moves toward the adjustment zone 8; when the fiber diameter information is less than the preset value, the metal cylinder 2 moves toward the stabilization zone 10.

[0076] Example 3

[0077] A method for online spinning of liquid-jet nanofibers includes:

[0078] S1, such as Figures 1-2As shown, a metal cylinder 2 is placed between the spinning die and the receiving plate 1, and the metal cylinder 2 is connected to the electrostatic generator 3. After the spinning solution is sprayed out from the spinning die, it is pulled by the high-speed airflow 7, passes through the metal cylinder 2, and finally deposits on the receiving plate 1, which is grounded. The basic length of the metal cylinder 2 is 7 / 15S. The basic length refers to the initial length of the metal cylinder 2, that is, the length of the metal cylinder 2 before any length change. S is 25cm.

[0079] The high-speed airflow 7 adopts an annular airflow 7, and the spinning solution jet 6 is located in the middle of the annular airflow 7. The metal cylinder 2 is made of copper-aluminum alloy.

[0080] S2. A high-speed camera 5 is set above the receiving plate 1 to acquire images of the fibers deposited on the receiving plate 1.

[0081] S3. Adjust the distance between the metal cylinder 2 and the spinning die head according to the feature information of the image until the feature information meets the preset value. The feature information includes at least the fiber diameter information. The preset diameter value is 2μm.

[0082] The acquisition of the fiber diameter information includes:

[0083] D1, as Figures 3-4 As shown, the image acquired by the high-speed camera 5 is divided into an overlapping area 11 and a non-overlapping area 1211. The overlapping area 11 refers to the area between the spinning liquid jets 6 ejected from adjacent spinnerets 4. The fibers in the non-overlapping area 1211 are refined and deposited from the spinning liquid jets 6 ejected from a single spinneret 4.

[0084] D2. The fiber diameter information is collected from the fiber images in the overlapping area 11 and the fiber images in the non-overlapping area 1211.

[0085] The fiber diameter information includes: fiber diameter size and fiber diameter deviation n. Let the fiber diameter of the non-overlapping region 1211 be d1 and the fiber diameter of the overlapping region 11 be d2, and n = |d1-d2| / d1.

[0086] S3 includes:

[0087] S31. The movement area of ​​the spinning solution jet 6 is sequentially divided into an adjustment zone 8, a disturbance zone 9, and a stabilization zone 10 along the movement direction. The spinning solution jet 6 is heated in the adjustment zone 8, the solvent evaporates, and the spinning solution reaches the overlapping concentration. The spinning solution jet 6 is entangled, bent, and refined in the disturbance zone 9. The spinning solution jet 6 is solidified into yarn before entering the stabilization zone 10, and the receiving plate 1 is located in the stabilization zone 10. Let the farthest distance between the disturbance zone 9 and the spinning die outlet be S, and the closest distance between the disturbance zone 9 and the spinning die outlet be 2 / 13S.

[0088] S32. The metal cylinder 2 moves within the disturbance zone 9. When the fiber diameter information is greater than the preset value, the metal cylinder 2 moves toward the adjustment zone 8; when the fiber diameter information is less than the preset value, the metal cylinder 2 moves toward the stabilization zone 10.

[0089] Example 4

[0090] A method for online spinning of liquid-jet nanofibers includes:

[0091] S1, such as Figures 1-2 As shown, a metal cylinder 2 is placed between the spinning die and the receiving plate 1, and the metal cylinder 2 is connected to the electrostatic generator 3. After the spinning solution is sprayed out from the spinning die, it is pulled by the high-speed airflow 7, passes through the metal cylinder 2, and finally deposits on the receiving plate 1, which is grounded. The basic length of the metal cylinder 2 is 1 / 3S. The basic length refers to the initial length of the metal cylinder 2, that is, the length of the metal cylinder 2 before any length change. S is 25cm.

[0092] The high-speed airflow 7 adopts an annular airflow 7, and the spinning solution jet 6 is located in the middle of the annular airflow 7. The metal cylinder 2 is made of copper-aluminum alloy.

[0093] S2. A high-speed camera 5 is set above the receiving plate 1 to acquire images of the fibers deposited on the receiving plate 1.

[0094] S3. Adjust the distance between the metal cylinder 2 and the spinning die head according to the feature information of the image until the feature information meets the preset value. The feature information includes at least the fiber diameter information. The preset diameter value is 2μm.

[0095] The acquisition of the fiber diameter information includes:

[0096] D1, as Figures 3-4 As shown, the image acquired by the high-speed camera 5 is divided into an overlapping area 11 and a non-overlapping area 1211. The overlapping area 11 refers to the area between the spinning liquid jets 6 ejected from adjacent spinnerets 4. The fibers in the non-overlapping area 1211 are refined and deposited from the spinning liquid jets 6 ejected from a single spinneret 4.

[0097] D2. The fiber diameter information is collected from the fiber images in the overlapping area 11 and the fiber images in the non-overlapping area 1211.

[0098] The fiber diameter information includes: fiber diameter size and fiber diameter deviation n. Let the fiber diameter of the non-overlapping region 1211 be d1 and the fiber diameter of the overlapping region 11 be d2, and n = |d1-d2| / d1.

[0099] S3 includes:

[0100] S31. The movement area of ​​the spinning solution jet 6 is sequentially divided into an adjustment zone 8, a disturbance zone 9, and a stabilization zone 10 along the movement direction. The spinning solution jet 6 is heated in the adjustment zone 8, the solvent evaporates, and the spinning solution reaches the overlapping concentration. The spinning solution jet 6 is entangled, bent, and refined in the disturbance zone 9. The spinning solution jet 6 is solidified into yarn before entering the stabilization zone 10, and the receiving plate 1 is located in the stabilization zone 10. Let the farthest distance between the disturbance zone 9 and the spinning die outlet be S, and the closest distance between the disturbance zone 9 and the spinning die outlet be 3 / 10S.

[0101] S32. The metal cylinder 2 moves within the disturbance zone 9. When the fiber diameter information is greater than the preset value, the metal cylinder 2 moves toward the adjustment zone 8; when the fiber diameter information is less than the preset value, the metal cylinder 2 moves toward the stabilization zone 10.

[0102] In this embodiment, the metal cylinder 2 is a telescopic cylinder. When adjusting the distance between the metal cylinder 2 and the spinning die head fails to make the feature information meet the preset value, the length of the metal cylinder 2 is adjusted. When the fiber diameter information is greater than the preset value, the length of the metal cylinder 2 is increased; when the fiber diameter information is less than the preset value, the length of the metal cylinder 2 is decreased.

[0103] Example 5

[0104] A method for online spinning of liquid-jet nanofibers includes:

[0105] S1, such as Figures 1-2 As shown, a metal cylinder 2 is placed between the spinning die and the receiving plate 1, and the metal cylinder 2 is connected to the electrostatic generator 3. After the spinning solution is sprayed out from the spinning die, it is pulled by the high-speed airflow 7, passes through the metal cylinder 2, and finally deposits on the receiving plate 1, which is grounded. The basic length of the metal cylinder 2 is 7 / 15S. The basic length refers to the initial length of the metal cylinder 2, that is, the length of the metal cylinder 2 before any length change. S is 25cm.

[0106] The high-speed airflow 7 adopts an annular airflow 7, and the spinning solution jet 6 is located in the middle of the annular airflow 7. The metal cylinder 2 is made of copper-aluminum alloy.

[0107] S2. A high-speed camera 5 is set above the receiving plate 1 to acquire images of the fibers deposited on the receiving plate 1.

[0108] S3. Adjust the distance between the metal cylinder 2 and the spinning die head according to the feature information of the image until the feature information meets the preset value. The feature information includes at least the fiber diameter information. The preset diameter value is 2μm.

[0109] The acquisition of the fiber diameter information includes:

[0110] D1, as Figures 3-4As shown, the image collected by the high-speed camera 5 is divided into an overlapping area 11 and a non-overlapping area 1211, the overlapping area 11 refers to the area between the adjacent jet 6 sprayed by the adjacent jet orifice 4, and the fiber in the non-overlapping area 1211 is deposited by the jet 6 sprayed by a single jet orifice 4;

[0111] D2, the collection object of the fiber diameter information includes the fiber image in the overlapping area 11 and the fiber image in the non-overlapping area 1211.

[0112] The fiber diameter information includes the fiber diameter size and the fiber diameter deviation n, wherein the fiber diameter in the non-overlapping area 1211 is d1, the fiber diameter in the overlapping area 11 is d2, and n = |d1-d2| / d1.

[0113] The S3 includes:

[0114] S31, sequentially divide the movement area of the jet 6 along the movement direction into an adjusting area 8, a disturbance area 9 and a stable area 10; the jet 6 is heated in the adjusting area 8, and the solvent volatilizes, so that the jet reaches the overlapping concentration; the jet 6 is entangled, curved and refined in the disturbance area 9; the jet 6 is solidified into a yarn before entering the stable area 10, and the receiving plate 1 is located in the stable area 10; the farthest distance between the disturbance area 9 and the outlet of the spinning nozzle is S, and the closest distance between the disturbance area 9 and the outlet of the spinning nozzle is 1 / 5S.

[0115] S32, the metal cylinder 2 moves in the disturbance area 9, when the fiber diameter information is greater than a preset value, the metal cylinder 2 moves towards the adjusting area 8; when the fiber diameter information is less than the preset value, the metal cylinder 2 moves towards the stable area 10.

[0116] Test

[0117] The solute of the spinning solution is PVP, the solvent is water, and the concentration of the spinning solution is 2wt%. The foregoing spinning solution is applied to the embodiments 1-5 to obtain the products 1-5, and the fiber morphology of the products 1-5 is measured as shown in the figure. Figures 5-9 As shown in the figure, the fiber uniformity is good.

[0118] The porosity of the products 1-5 is detected by the density method, and the detection results are shown in Table 1.

[0119] Table 1

[0120] Product 1 Product 2 Product 3 Product 4 Product 5 Porosity / % 82 79 85 87

[0121] As shown in Table 1, the method of the present application not only makes the diameter of the product controllable, but also makes the porosity of the product basically above 80%.

[0122] On the basis of the embodiment 1, only the diameter preset value is changed, and different fiber diameter deviations are obtained, as shown in Table 2.

[0123] Table II

[0124]

[0125] As shown in Table II, when the diameter preset value decreases, the diameter deviation degree first decreases and then increases, and when the diameter preset value is too low, the deviation degree greatly increases, so the preset diameter is preferably greater than 0.1 μm.

[0126] The preferred embodiments of the present application have been described above with the preferred embodiments, but the present application is not limited to them and can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A liquid spray nanofiber on-line yarn formation method, characterized by, The application relates to an online nanofiber yarn forming method. S1, arranging a metal cylinder between a spinning nozzle and a receiving plate, the metal cylinder being connected with an electrostatic generator; After the spinning solution is sprayed from the spinning nozzle, the spinning solution passes through the metal cylinder under the pulling of high-speed airflow and is finally deposited on the receiving plate; S2, arranging a high-speed camera above the receiving plate to collect images of the deposited fibers on the receiving plate; S3, adjusting the distance between the metal cylinder and the spinning nozzle according to characteristic information of the images until the characteristic information meets preset values, the characteristic information at least including fiber diameter information; The S3 includes: S31, sequentially dividing a movement region of the spinning solution jet along a movement direction into an adjusting zone, a disturbance zone and a stable zone; the spinning solution jet is heated in the adjusting zone, solvent volatilizes, and the spinning solution reaches an overlapping concentration; the spinning solution jet occurs entanglement, bending and thinning in the disturbance zone; the spinning solution jet is solidified into a yarn before entering the stable zone, and the receiving plate is located in the stable zone; S32, moving the metal cylinder in the disturbance zone; The collection of the fiber diameter information includes: D1, dividing the images collected by the high-speed camera into overlapping zones and non-overlapping zones, the overlapping zones referring to regions between spinning solution jets sprayed from adjacent spinning holes, and the fibers in the non-overlapping zones being deposited by spinning solution jets sprayed from single spinning holes; D2, the collection object of the fiber diameter information including fiber images in the overlapping zones and fiber images in the non-overlapping zones; The fiber diameter information includes fiber diameter size and fiber diameter deviation n, the fiber diameter in the non-overlapping zones being d1, the fiber diameter in the overlapping zones being d2, and n=|d1-d2| / d1; The farthest distance between the disturbance zone and the spinning nozzle outlet is S, and the nearest distance between the disturbance zone and the spinning nozzle outlet is 2 / 13S-3 / 10S; The basic length of the metal cylinder is 1 / 3S-3 / 5S.

2. The liquid spray nanofiber on-line yarn formation method according to claim 1, wherein, S32 specifically includes: when the fiber diameter information is greater than a preset value, the metal cylinder moves towards the adjusting zone; and when the fiber diameter information is less than the preset value, the metal cylinder moves towards the stable zone.

3. The liquid spray nanofiber on-line yarn formation method according to claim 1, wherein, The metal cylinder is a telescopic cylinder, and the length of the metal cylinder is adjusted when the characteristic information cannot meet the preset values by adjusting the distance between the metal cylinder and the spinning nozzle.

4. The liquid spray nanofiber on-line yarn formation method according to claim 3, wherein, When the fiber diameter information is greater than the preset value, the length of the metal cylinder is increased; and when the fiber diameter information is less than the preset value, the length of the metal cylinder is decreased.

5. A nanofiber prepared by the online nanofiber yarn forming method according to any one of claims 1-4.

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