Hollow wire electrode, electrospinning device and application, electrospinning method

Abstract

The present invention discloses a hollow wire electrode, an electrospinning device and its application, and an electrospinning method. The hollow wire electrode comprises an inner hollow tube and an outer metal layer; a plurality of through holes I are provided on the semicircular side surface of the inner hollow tube; the semicircular side surface of the inner hollow tube refers to the side surface of the circumferential section of the inner hollow tube with a central angle of 180°; a plurality of through holes II are provided on the semicircular side surface of the outer metal layer; the semicircular side surface of the outer metal layer refers to the side surface of the circumferential section of the outer metal layer with a central angle of 180°; through holes I and through holes II form a continuous through hole. When the hollow wire electrode of the present invention is used for electrospinning, the phenomenon of floating and broken fibers is significantly reduced, and the continuous production stability, raw material utilization rate, yield rate, and production efficiency are all improved.

Description

Technical Field

[0001] The present invention specifically relates to a hollow wire electrode, an electrospinning device and application, and an electrospinning method. Background Art

[0002] With the development of modern science and technology, researchers have put forward increasingly higher requirements for material properties. Among the materials that are rapidly developing and widely used, nanofibers have extremely broad application prospects in high-performance drives, energy engineering, filtration materials, medical hygiene and catalysis due to their unique size effect. It has become one of the important pillars driving the progress of contemporary science and technology. Therefore, higher requirements are placed on the efficient and stable preparation technology of nanofibers.

[0003] Electrospinning, with its advantages of simple manufacturing equipment and controllable process, has been recognized as one of the most effective methods for producing nanofibers in recent years. Electrospinning uses high-voltage static electricity to charge a polymer solution. When the electric field overcomes the surface tension and viscosity of the solution, a tiny jet of fluid is ejected from the surface. The jet is stretched and refined by the electric field, and as the solution evaporates, it eventually solidifies into nanofibers with diameters ranging from tens to hundreds of nanometers.

[0004] Usually, needle-free electrospinning equipment uses a smooth or spiral metal wire as the wire electrode. A liquid supply pump is used to supply the spinning liquid to the coating tank to immerse the wire electrode. The coating tank cooperates with the reciprocating equipment table to perform reciprocating motion to scrape the spinning liquid on the wire electrode, and then excitation and splitting occur under the action of the electric field.

[0005] The existing electrospinning process has the following main defects:

[0006] (1) Low product uniformity: The spinning solution coated on the wire electrode is in direct contact with the air for a long time, and the spinning solution is prone to various abnormalities, such as water absorption and deterioration of the solution, solute precipitation, abnormal increase in solution viscosity, etc. In mild cases, it will affect the stability of the spinning solution, and then have a significant negative impact on the electrospinning excitation process, resulting in droplet splashing, insufficient fiber stretching, and a large number of defects in the product. In severe cases, the precipitated solute or deteriorated solution will coat the surface of the wire electrode, making it impossible for the spinning solution to be normally excited in the wrapped area, and the product uniformity will be significantly reduced. As the production time increases, the impact on the stability of continuous production becomes more and more serious.

[0007] (2) Low raw material utilization rate: The spinning solution deteriorates after being exposed to the air for a long time, making it more difficult to recycle and reuse, or even impossible to recycle, which ultimately significantly reduces the raw material utilization rate and increases product costs.

[0008] (3) Low product yield: In the reciprocating wire electrode coating method, the solution on the wire electrode is excited along with the fiber, and the amount of solution on the wire electrode will decrease along with the excitation. When the amount of solution is too low, the excitation stability of the wire electrode will be significantly reduced. Therefore, in order to ensure the stability of the excitation process, the demand for the amount of liquid supply is much larger than the amount of spinning liquid for normal and complete excitation of the equipment (i.e., excessive liquid supply is required). This results in a large amount of solution being scraped off directly. The solution scraped to both sides is exposed to the air for a long time and will deteriorate, resulting in an abnormal increase in the viscosity of the spinning liquid. Under the drive of the high-voltage electric field, serious splashing may occur, which will eventually make the products on both sides unusable and the product yield will also be reduced.

[0009] (4) The phenomenon of floating and broken threads is serious, and there are hidden dangers: the excitation points of the reciprocating wire electrode coating method are randomly distributed. Under the action of gravity, the spinning solution is easy to gather into droplets at the bottom of the wire electrode. The tip discharge effect increases the charge density on the droplets, making it easier to excite. This causes the solution to be excited downward and then fly upward under the action of the electric field force. It is easy to cause floating and broken threads, affecting the uniformity and quality of the product. At the same time, it is easy to accumulate nanofibers in the spinning chamber, posing a fire hazard.

[0010] Increasing the coating speed can reduce the impact of the above problems to a certain extent. However, due to the time difference from solution coating to excitation in electrospinning (about 1-2 seconds), and the liquid supply method of reciprocating wire electrode coating, it must go through a cycle of "erasing and coating at the same time - waiting - excitation - erasing and coating at the same time", and the proportion of non-excitation time in the total production time continues to increase with the increase of coating speed. In extreme cases, if the reciprocating time is shortened to less than 2 seconds, the output can be regarded as zero, which will ultimately lead to low production efficiency.

[0011] The above-mentioned defects existing in the current electrospinning process need to be solved urgently. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to overcome the significant drawbacks of existing electrospinning processes, such as the significant phenomenon of drifting and breaking of fibers, by providing a hollow wire electrode, an electrospinning device and its application, and an electrospinning method. Using the hollow wire electrode of the present invention for electrospinning significantly reduces the phenomena of drifting and breaking of fibers.

[0013] The present invention provides the following technical solutions to solve the above technical problems.

[0014] The present invention provides a hollow wire electrode comprising an inner hollow tube and an outer metal layer;

[0015] A plurality of through holes I are provided on the semicircular side surface of the inner hollow tube, wherein the semicircular side surface of the inner hollow tube refers to the side surface of the inner hollow tube having a central angle of 180° corresponding to the circumferential direction of the cross section; a plurality of through holes II are provided on the semicircular side surface of the outer metal layer, wherein the semicircular side surface of the outer metal layer refers to the side surface of the outer metal layer having a central angle of 180° corresponding to the circumferential direction of the cross section; the through holes I and the through holes II form a continuous through hole;

[0016] (1) The through hole I meets the following conditions:

[0017] The distance between any two adjacent through holes I on the same tangent plane in the direction of the extension line of the hollow wire electrode is 2-8 cm in the direction of the extension line of the hollow wire electrode;

[0018] The spacing between any two adjacent through holes I on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 2 of the circumference;

[0019] (2) The through hole II meets the following conditions:

[0020] The distance between any two adjacent through holes II on the same tangent plane in the direction of the extension line of the hollow wire electrode is 2-8 cm in the direction of the extension line of the hollow wire electrode;

[0021] The spacing between any two adjacent through holes II on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 2 of the circumference;

[0022] The circumferential direction of the hollow wire electrode refers to a direction perpendicular to the extension line direction of the hollow wire electrode.

[0023] In the present invention, preferably, the distance between any two adjacent through holes I on the same tangent plane in the direction of the extension line of the hollow wire electrode in the direction of the extension line of the hollow wire electrode is 3-7 cm, such as 4 cm, 5 cm or 6 cm.

[0024] In the present invention, preferably, the distance between any two adjacent through holes II on the same tangent plane in the direction of the extension line of the hollow wire electrode is 3-7 cm, such as 4 cm, 5 cm or 6 cm.

[0025] In the present invention, preferably, the distance between any two adjacent through holes I on the same tangent plane in the circumferential direction of the hollow wire electrode in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 3 of the circumference, for example, 1 / 4 of the circumference.

[0026] In the present invention, preferably, the distance between any two adjacent through holes II on the same tangent plane in the circumferential direction of the hollow wire electrode in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 3 of the circumference, for example, 1 / 4 of the circumference.

[0027] In the present invention, preferably, the through hole I corresponds to the through hole II one to one, and the "one to one correspondence" means that the through hole I and the through hole II can completely correspond to and overlap with each other.

[0028] In the present invention, the outer diameter of the inner hollow tube may be 2-5 mm, such as 3 mm or 4 mm.

[0029] In the present invention, the inner diameter of the inner hollow tube may be 1-4 mm, such as 2 mm or 3 mm.

[0030] In the present invention, the material of the inner hollow tube can be a conventional material in the art, such as polytetrafluoroethylene.

[0031] In the present invention, the thickness of the outer metal layer may be 0.5-1 mm, for example 0.5 mm.

[0032] In the present invention, the outer metal layer is generally connected to a high-voltage power supply; the high-voltage power supply provides a positive voltage.

[0033] The present invention also provides an electrospinning device, which comprises the hollow wire electrode as described above.

[0034] In the present invention, the hollow wire electrode is preferably placed horizontally in the electrospinning device, with the side provided with the through hole facing upward, where "upward" refers to a direction away from the ground.

[0035] In some embodiments of the present invention, the electrospinning device includes a liquid storage cylinder, a liquid supply pump, an adapter, a hollow wire electrode, a high-voltage power supply, and a receiving device; the lower portion of the liquid storage cylinder is connected to the liquid supply pump via a pipeline A; one side of the liquid supply pump is connected to one end of the hollow wire electrode via a pipeline B, and the pipeline B is connected to the hollow wire electrode via the adapter; the end of the hollow wire electrode not connected to the pipeline B is connected to the high-voltage power supply via a wire;

[0036] The hollow wire electrode is placed horizontally with the side provided with the through hole facing upward, where "upward" refers to a direction away from the ground;

[0037] The receiving device is located above the hollow wire electrode and is parallel to the hollow wire electrode in the direction of the extension line of the hollow wire electrode.

[0038] In the description of the present invention, the terms "lower" and "above" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0039] The present invention also provides an electrospinning method, wherein the spinning solution is passed into the hollow wire electrode as described above, or the spinning solution is passed into the hollow wire electrode in the electrospinning device as described above;

[0040] The spinning solution is supplied at a rate of 3.5-9.5 mL / min per meter of hollow wire electrode;

[0041] When the spinning solution is passed into the hollow wire electrode as described above, the flow direction of the spinning solution is the extension direction of the hollow wire electrode;

[0042] When the spinning solution is passed into the hollow wire electrode in the electrospinning device as described above, the flow direction of the spinning solution is opposite to the direction of the current introduced into the hollow wire electrode.

[0043] In the present invention, the liquid supply rate is preferably 4-8 mL / min per meter of hollow wire electrode, for example, 5 mL / min per meter of hollow wire electrode, 6 mL / min per meter of hollow wire electrode, or 7 mL / min per meter of hollow wire electrode.

[0044] In some embodiments of the present invention, the electrospinning method comprises the following steps:

[0045] The spinning liquid is stored in a solution cylinder and is pumped into the hollow wire electrode through an adapter by a liquid supply pump. The spinning liquid is discharged through the through holes in the inner and outer layers of the hollow wire electrode. The metal layer on the surface of the hollow wire electrode is connected to the high-voltage power supply with a wire. When the high-voltage power supply is turned on, a high voltage is applied to the hollow wire electrode, so that the spinning liquid is immediately stretched and refined under the action of the high-voltage electric field after being extruded and solidified into nanofibers, and is finally collected by the non-woven fabric substrate carried by the receiving device.

[0046] The present invention also provides a hollow wire electrode as described above, or use of the electrospinning device as described above in an electrospinning process.

[0047] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0048] The reagents and raw materials used in the present invention are commercially available.

[0049] The positive progress effect of the present invention is:

[0050] 1. The hollow wire electrode of the present invention can adjust the excitation point so that most of the excitation process occurs above the wire electrode, significantly reducing the floating wire phenomenon.

[0051] 2. The hollow wire electrode of the present invention can seal the spinning solution in the pipeline, and it only comes into direct contact with the air briefly before excitation, which is not easy to cause deterioration and precipitation problems. Under normal circumstances, there is no problem of the wire electrode being covered by precipitates and thus unable to be excited, and the continuous production stability is significantly improved.

[0052] 3. The hollow wire electrode of the present invention can keep the spinning solution in a continuously excited state, thereby improving the uniformity of the product and the production efficiency.

[0053] 4. The hollow wire electrode of the present invention can avoid the problem of excessive liquid supply, and the utilization rate of raw materials is significantly improved; there is no phenomenon of solution being scraped to the sides and deteriorating, which avoids the defects caused by splashing of solution on both sides and improves the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Schematic diagram of the overall structure of the hollow wire electrode in Example 1.

[0055] Figure 2 This is a schematic structural diagram of the hollow wire electrode of Example 1 in the direction of the extension line of the hollow wire electrode.

[0056] Figure 3 Schematic diagram of the side opening structure of the hollow wire electrode of Example 1 in the circumferential direction of the hollow wire electrode.

[0057] Figure 4 Schematic diagram of the structure of the electrospinning device used in the present invention.

[0058] The reference numerals are as follows:

[0059] Inner hollow tube 1

[0060] Outer metal layer 2

[0061] Through hole 3

[0062] Liquid storage cylinder 4

[0063] Liquid supply pump 5

[0064] Adapter 6

[0065] Hollow wire electrode 7

[0066] High voltage power supply 8

[0067] Receiving device 9 DETAILED DESCRIPTION

[0068] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0069] The reagents used in the examples of the present invention are all commercially available products.

[0070] Combined with attachment Figure 1-3 The hollow wire electrode of the present invention is described clearly and completely. The details are as follows:

[0071] like Figure 1 As shown, the hollow wire electrode used in the electrospinning method of the present invention comprises: an inner hollow tube 1 and an outer metal layer 2; a plurality of through holes I are provided on the semicircular side surface of the inner hollow tube 1; the semicircular side surface of the inner hollow tube 1 refers to the side surface with a central angle of 180° corresponding to the circumferential direction section of the inner hollow tube 1; a plurality of through holes II are provided on the semicircular side surface of the outer metal layer 2; the semicircular side surface of the outer metal layer 2 refers to the side surface with a central angle of 180° corresponding to the circumferential direction section of the outer metal layer 2; the through holes I and the through holes II form a continuous through hole;

[0072] (1) The through hole I meets the following conditions:

[0073] The distance between any two adjacent through holes I on the same tangent plane in the direction of the extension line of the hollow wire electrode is 2-8 cm in the direction of the extension line of the hollow wire electrode;

[0074] The spacing between any two adjacent through holes I on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 2 of the circumference;

[0075] (2) Through hole II meets the following conditions:

[0076] The distance between any two adjacent through holes II on the same tangent plane in the direction of the extension line of the hollow wire electrode is 2-8 cm in the direction of the extension line of the hollow wire electrode;

[0077] The distance between any two adjacent through holes II on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 2 of the circumference;

[0078] The circumferential direction of the hollow wire electrode refers to the direction perpendicular to the extension line direction of the hollow wire electrode;

[0079] Specifically, the distance between any two adjacent through holes I on the same tangent plane in the direction of the extension line of the hollow wire electrode is 3-7 cm, such as 4 cm, 5 cm or 6 cm.

[0080] Specifically, the distance between any two adjacent through holes II on the same tangent plane in the direction of the extension line of the hollow wire electrode is 3-7 cm, for example, 4 cm, 5 cm or 6 cm.

[0081] Specifically, the spacing between any two adjacent through holes I on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 3 of the circumference, for example, 1 / 4 of the circumference;

[0082] Specifically, the spacing between any two adjacent through holes II on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 3 of the circumference, for example, 1 / 4 of the circumference;

[0083] Specifically, the through hole I corresponds to the through hole II one by one, and "one by one" means that the through hole I and the through hole II can completely correspond to each other;

[0084] Specifically, the outer diameter of the inner hollow tube 1 is 2-5 mm, for example, 3 mm or 4 mm;

[0085] Specifically, the inner diameter of the inner hollow tube 1 is 1-4 mm, for example, 2 mm or 3 mm;

[0086] Specifically, the material of the inner hollow tube 1 is polytetrafluoroethylene;

[0087] Specifically, the thickness of the outer metal layer 2 is 0.5-1 mm, for example, 0.5 mm;

[0088] Specifically, the outer metal layer 2 is connected to a high-voltage power supply; the high-voltage power supply provides a positive voltage.

[0089] like Figure 4 As shown, the electrospinning device used in the electrospinning method of the present invention includes a liquid storage cylinder 4, a liquid supply pump 5, an adapter 6, a hollow wire electrode 7, a high-voltage power supply 8, and a receiving device 9; the lower portion of the liquid storage cylinder 4 is connected to the liquid supply pump 5 via a pipeline A; one side of the liquid supply pump 5 is connected to one end of the hollow wire electrode 7 via a pipeline B, and the pipeline B is connected to the hollow wire electrode 7 via the adapter 6; the end of the hollow wire electrode not connected to the pipeline B is connected to the high-voltage power supply 8 via a wire;

[0090] The hollow wire electrode 7 is placed horizontally with the side provided with the through hole facing upwards, where “upwards” refers to the direction away from the ground;

[0091] The receiving device 9 is located above the hollow wire electrode 7 and is parallel to the hollow wire electrode in the direction of the extension line of the hollow wire electrode;

[0092] The terms "lower" and "upper" indicate positions or locations based on Figure 4 The orientation or position relationship shown.

[0093] The electrospinning method of the present invention comprises the following steps:

[0094] The spinning liquid flows into the inner hollow tube 1 (polytetrafluoroethylene inner tube) of the hollow wire electrode by the liquid supply pump in the electrospinning device, and is squeezed onto the surface of the wire electrode along the through hole 3 on the hollow wire electrode. The outer metal layer 2 of the hollow wire electrode is connected to the high-voltage power supply with a wire. When the high-voltage power supply is turned on, a high voltage is applied to the hollow wire electrode. Under the action of the high-voltage power supply, the squeezed solution is excited and stretched and solidified at the through hole 3 on the hollow wire electrode, and finally a nanofiber product is formed.

[0095] Example 1

[0096] In the electrospinning method of this embodiment, the specific experimental parameters are as follows:

[0097] Spinning solution: a conventional spinning solution for preparing nanofibers in the art, such as polyurethane electrospinning solution.

[0098] Spinning parameters: spinning voltage 45 kV, distance between electrode wire and collecting substrate 25 cm, substrate winding speed 0.1 m / min, temperature inside the spinning chamber 35 °C, humidity inside the spinning chamber 30%, spinning solution supply rate: 5 mL / min per meter of hollow wire electrode.

[0099] Electrospinning device: electrospinning machine model MF01-006 from Foshan Qingzi Precision Measurement and Control Technology Co., Ltd.

[0100] The overall structure of the hollow wire electrode in the electrospinning device is as follows:

[0101] The inner layer of the hollow wire electrode is a polytetrafluoroethylene hollow tube (3mm outer diameter, 2mm inner diameter), and the outer layer is a metal coating (0.5mm thick). The outer layer is connected to a high-voltage power supply to provide positive high voltage. The inner polytetrafluoroethylene hollow tube is provided with a number of through-holes I (0.3mm diameter), and the outer metal layer is provided with a number of through-holes II (0.3mm diameter). Through-holes I and II completely overlap. The spacing between any two adjacent through-holes I on the same tangent plane along the hollow wire electrode's extension line is 3cm. The angle between any two adjacent through-holes I on the same tangent plane along the hollow wire electrode's circumference is 90° (i.e., the spacing between any two adjacent through-holes I on the same tangent plane along the hollow wire electrode's circumference is 1 / 4 of the circumference).

[0102] The nanofiber production efficiency of Example 1 is 10 g / min.

[0103] Example 2

[0104] In the hollow wire electrode used in Example 2, there is only one through hole I on the same cross-section in the circumferential direction of the inner polytetrafluoroethylene hollow tube of the hollow wire electrode, and the through holes I are arranged in the extension direction of the hollow wire electrode. There is only one through hole II on the same cross-section in the circumferential direction of the outer metal layer, and the through hole I completely overlaps with the through hole II. The spacing between any two adjacent through holes I on the same cross-section in the extension direction of the hollow wire electrode is 6 cm. The other structural parameters are the same as those of the hollow wire electrode used in Example 1; the other experimental conditions are the same as those in Example 1.

[0105] The nanofiber production efficiency of Example 2 is 3 g / min.

[0106] Example 3

[0107] In the hollow wire electrode used in Example 3, the spacing between any two adjacent through-holes I on the same tangent plane in the direction of the hollow wire electrode extension was 2 cm. Other structural parameters were the same as those of the hollow wire electrode used in Example 1, and all other experimental conditions were the same as in Example 1. During the electrospinning process, abnormal jittering of the jet was observed, and the nanofibers were partially repelled during flight, preventing them from being effectively collected directly by the negative electrode plate.

[0108] The nanofiber production efficiency of Example 3 is 6 g / min.

[0109] Example 4

[0110] In the hollow wire used in Example 4, the angle between any two adjacent through-holes I on the same circumferential plane of the hollow wire electrode was 30° (i.e., the circumferential spacing between any two adjacent through-holes I on the same circumferential plane of the hollow wire electrode was 1 / 12 of the circumference). Other structural parameters were identical to those of the hollow wire electrode used in Example 1, and all other experimental conditions were the same as in Example 1. Significant repulsion was observed between the two nanofiber bundles excited at the same cross-sectional point, resulting in fiber disturbance, drifting, and poor collection.

[0111] The nanofiber production efficiency of Example 4 is 6 g / min.

[0112] Example 5

[0113] In the hollow-wire electrode used in Example 5, the angle between any two adjacent through-holes I on the same circumferential plane of the hollow-wire electrode was 180° (i.e., the spacing between any two adjacent through-holes I on the same circumferential plane of the hollow-wire electrode was 1 / 2 of the circumference). Other structural parameters were identical to those of the hollow-wire electrode used in Example 1, and all other experimental conditions were the same as in Example 1. It was observed that due to gravity, the extruded spinning solution tended to slide downward, and the excited jet partially first descended and then bent upward, resulting in some fiber breakage and incomplete collection. The nanofiber production efficiency of Example 5 was 7 g / min.

[0114] Comparative Example 1

[0115] Comparative Example 1 employed the same hollow wire electrode as in Example 1, adjusting the liquid feed rate to 10 mL / min per meter of the hollow wire electrode. All other experimental conditions remained the same. During the electrospinning process, significant excess solution accumulation was observed. A large amount of solution accumulated on the lower half of the wire electrode, forming droplets that generated a jet and subsequently excited the nanofibers downward, resulting in significant drifting and breakage. Furthermore, excessive spinning solution accumulation absorbed moisture from the air, increasing its viscosity. Upon excitation, this high-viscosity solution splattered, significantly impacting product quality and uniformity.

[0116] The nanofiber production efficiency of Comparative Example 1 is 8 g / min.

[0117] Comparative Example 2

[0118] Comparative Example 2 used the same hollow wire electrode as in Example 1, with the liquid supply rate adjusted to 3 mL / min per meter of the hollow wire electrode. All other experimental conditions remained the same as in Example 1. During the electrospinning process, insufficient liquid supply was observed in the spinning solution. After a period of jet excitation, the jet automatically stopped due to insufficient spinning solution, significantly affecting spinning efficiency and reducing nanofiber yield. Furthermore, partial spinning solution coagulation was likely to occur, hindering continuous production.

[0119] The nanofiber production efficiency of Comparative Example 2 is 5 g / min.

[0120] The experimental conditions of Examples 1-5 and Comparative Examples 1-2 are changed as shown in Table 1 below:

[0121] Table 1

[0122]

[0123] Effect Example 1 Production Efficiency Test

[0124] Test objects: nanofibers produced by the electrospinning process of Example 1 and Comparative Example 1.

[0125] Test method:

[0126] 1. Using the same circular sampler (sampling area S m 2 ) Five samples were randomly cut from different positions on the prepared nanofiber membrane, weighed separately, and the average mass was calculated and recorded as A1g;

[0127] 2. Using the same circular sampler (sampling area S m 2 ) Five samples were randomly cut from different positions on the prepared nanofiber membrane, weighed separately, and the average mass was calculated and recorded as A2g;

[0128] 3. Calculate production efficiency (αg / m 2 )

[0129] α=(A2-A1) / S

[0130] Test results: as shown in Table 2 below.

[0131] Table 2

[0132]

[0133] Note: The floating silk phenomenon and the continuous production stability effect in Table 2 above can be observed with the naked eye during the electrospinning process.

[0134] After a lot of experimental research, the inventor found that:

[0135] 1. The spacing between the through holes on the hollow wire electrode should not be too close, because after the spinning solution is excited, it will carry a large amount of positive charge and fly in the spinning chamber. If the two excitation points (through holes) are too close, the two bundles of nanofiber solutions will repel each other, causing abnormal stretching and affecting product quality. If the distance is too far, the output per unit length of the wire electrode will be too low, there will be fewer excitation points, and the spinning efficiency will be reduced.

[0136] 2. The through-holes directly above the hollow wire electrode are positioned in a specific location. For example, when the spacing between any two adjacent through-holes I on the same tangent plane in the circumferential direction of the hollow wire electrode on the inner hollow tube is 1 / 4 of the circumference (i.e., the angle between through-holes I is 90°), and the spacing between any two adjacent through-holes II on the same tangent plane in the circumferential direction of the hollow wire electrode on the outer metal layer is 1 / 4 of the circumference (i.e., the angle between through-holes II is 90°), and through-holes I and II completely overlap, this has the following advantages: it effectively avoids the mutual charge interference problem after the solutions on both sides are excited. After the solution is stretched in the stable stage, it is stretched to both sides to form nanofibers. At this time, the distance between the two bundles of nanofibers means that the positive charge they carry will not affect the normal stretching of other nanofibers.

[0137] 3. The liquid supply speed of the spinning solution must match the length of the hollow wire electrode. The use of the hollow wire electrode of the present invention with a specific liquid supply speed can ensure that the equipment is in a continuous and stable excitation state without excess solution. Specifically:

[0138] During the electrospinning process, the spinning solution is in contact with the air only at the through-holes, but is rapidly excited under the action of high voltage electricity, and the problem of solution absorption and deterioration is not likely to occur. At the same time, the through-holes provided only on the semi-circular side of the inner hollow tube and the semi-side of the outer metal layer effectively inhibit the process of the solution gathering into droplets below the wire electrode due to gravity and then being excited, so that the solution can only be excited in the upper half of the wire electrode, effectively suppressing the floating and broken fibers caused by the downward excitation of the nanofibers, and improving the stability of the nanofiber products. Even if a small amount of solution slowly flows to the lower half of the wire electrode, gradual solute condensation and precipitation will occur, forming a layer of polymer film on the lower half of the wire electrode, covering the lower half of the wire electrode, making it more difficult for the solution to gather into droplets to form a jet, while also increasing the difficulty of excitation, further suppressing the excitation of the solution in the lower half of the wire electrode;

[0139] Therefore, the continuous excitation effect of the electrospinning method using the hollow wire electrode of the present invention can be significantly improved compared with the traditional scraping method. Only by adjusting the appropriate liquid supply parameters, the goal of the amount of liquid supply and the amount of excitation can be achieved, and the raw material utilization rate is significantly improved.

Claims

1. A hollow wire electrode, characterized in that: It includes an inner hollow tube and an outer metal layer; A plurality of through holes I are provided on the semicircular side surface of the inner hollow tube, wherein the semicircular side surface of the inner hollow tube refers to the side surface of the inner hollow tube having a central angle of 180° corresponding to the circumferential direction of the cross section; a plurality of through holes II are provided on the semicircular side surface of the outer metal layer, wherein the semicircular side surface of the outer metal layer refers to the side surface of the outer metal layer having a central angle of 180° corresponding to the circumferential direction of the cross section; the through holes I and the through holes II form a continuous through hole; (1) The through hole I satisfies the following conditions: The distance between any two adjacent through holes I on the same tangent plane in the direction of the extension line of the hollow wire electrode is 2-8 cm in the direction of the extension line of the hollow wire electrode; The spacing between any two adjacent through holes I on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 2 of the circumference; (2) The through hole II meets the following conditions: The distance between any two adjacent through holes II on the same tangent plane in the direction of the extension line of the hollow wire electrode is 2-8 cm in the direction of the extension line of the hollow wire electrode; The spacing between any two adjacent through holes II on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 2 of the circumference; The circumferential direction of the hollow wire electrode refers to a direction perpendicular to the extension line direction of the hollow wire electrode.

2. The hollow wire electrode according to claim 1, wherein The distance between any two adjacent through holes I on the same tangent plane in the direction of the extension line of the hollow wire electrode is 3-7 cm in the direction of the extension line of the hollow wire electrode; And / or, the distance between any two adjacent through holes II on the same tangent plane in the direction of the extension line of the hollow wire electrode is 3-7 cm in the direction of the extension line of the hollow wire electrode.

3. The hollow wire electrode according to claim 2, wherein: The distance between any two adjacent through holes I on the same tangent plane in the direction of the extension line of the hollow wire electrode is 4 cm, 5 cm or 6 cm in the direction of the extension line of the hollow wire electrode.

4. The hollow wire electrode according to claim 2, wherein: The distance between any two adjacent through holes II on the same tangent plane in the direction of the extension line of the hollow wire electrode is 4 cm, 5 cm or 6 cm in the direction of the extension line of the hollow wire electrode.

5. The hollow wire electrode according to claim 1, wherein The spacing between any two adjacent through holes I on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 3 of the circumference; and / or, the spacing between any two adjacent through holes II on the same tangent plane in the circumferential direction of the hollow wire electrode in the circumferential direction of the hollow wire electrode is 1 / 5-1 / 3 of the circumference; And / or, the through hole I corresponds to the through hole II on a one-to-one basis, and the “one-to-one correspondence” means that the through hole I and the through hole II can completely correspond to and overlap with each other.

6. The hollow wire electrode according to claim 5, characterized in that The distance between any two adjacent through holes I on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 4 of the circumference.

7. The hollow wire electrode according to claim 5, wherein: The distance between any two adjacent through holes II on the same tangent plane in the circumferential direction of the hollow wire electrode is 1 / 4 of the circumference.

8. The hollow wire electrode according to claim 1, wherein The outer diameter of the inner hollow tube is 2-5 mm; And / or, the inner diameter of the inner hollow tube is 1-4 mm.

9. The hollow wire electrode according to claim 8, wherein The outer diameter of the inner hollow tube is 3 mm or 4 mm.

10. The hollow wire electrode according to claim 8, wherein The inner diameter of the inner hollow tube is 2 mm or 3 mm.

11. The hollow wire electrode according to claim 1, wherein The material of the inner hollow tube is polytetrafluoroethylene; And / or, the thickness of the outer metal layer is 0.5-1 mm.

12. The hollow wire electrode according to claim 11, wherein The thickness of the outer metal layer is 0.5 mm.

13. An electrospinning device, characterized in that: It comprises the hollow wire electrode according to any one of claims 1 to 12.

14. The electrospinning device according to claim 13, wherein The hollow wire electrode is placed horizontally in the electrospinning device with the side provided with the through hole facing upward, where "upward" refers to a direction away from the ground.

15. An electrospinning method, characterized in that: Passing the spinning solution into the hollow wire electrode according to any one of claims 1 to 12, or passing the spinning solution into the hollow wire electrode in the electrospinning device according to claim 13 or 14; The spinning solution is supplied at a rate of 3.5-9.5 mL / min per meter of hollow wire electrode; When the spinning solution is passed into the hollow wire electrode according to any one of claims 1 to 12, the flow direction of the spinning solution is the extension direction of the hollow wire electrode; When the spinning solution is passed into the hollow wire electrode in the electrospinning device according to claim 13 or 14, the flow direction of the spinning solution is opposite to the direction of the current introduced into the hollow wire electrode.

16. The electrospinning method according to claim 15, wherein The liquid supply speed is 4-8 mL / min per meter of hollow wire electrode.

17. The electrospinning method according to claim 16, wherein: The liquid supply speed is 5 mL / min per meter of the hollow wire electrode, 6 mL / min per meter of the hollow wire electrode, or 7 mL / min per meter of the hollow wire electrode.

18. Use of the hollow wire electrode according to any one of claims 1 to 12, or the electrospinning device according to claim 13 or 14 in an electrospinning process.

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