Nozzle head and electrospinning device

Abstract

To improve fiber assembly productivity.SOLUTION: A nozzle head 20 comprises: a cylindrical head body 30 having a spinning hole 36 opening on an outer peripheral surface 30A and feed passages 34, 35 to feed spinning liquid 31 to the spinning hole 36; and a spinning electrode 50 that has potential difference between itself and a collector electrode 17 and electrifies the spinning liquid 31. The nozzle head 20 is constituted so as to make a collecting member 14 collect the spinning liquid 31 that is ejected from the spinning hole 36 to the outside of the head body 30 and formed into ultrafine fibers by electrostatic force. Surface roughness of an opening edge 36E of the spinning hole 36 at the outer peripheral surface 30A of the head body 30 is larger than surface roughness of an inner peripheral surface 30B of the head body 30.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a nozzle head and an electrospinning device. [Background technology]

[0002] Patent Document 1 discloses an electrospinning apparatus that produces a fiber aggregate consisting of ultrafine fibers by spraying a spinning solution from a spinning hole of a nozzle head using a potential difference and collecting the ultrafine fibers on a sheet-like collecting member. Examples of fiber aggregates include nonwoven fabrics used as separators for secondary batteries. This electrospinning apparatus has the advantage of easily producing ultrafine fibers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-074630 Summary of the Invention [Problem to be solved by the invention]

[0004] In the electrospinning apparatus described above, when collecting the spinning solution in the collecting member, the spinning solution is converted into ultrafine fibers with a small volume, so the amount collected per unit time is small. In addition, a portion of the spinning solution remains attached to the outer peripheral surface of the nozzle head without being sprayed toward the collecting member. As a result, the productivity of the fiber aggregate is low, and improvement is desired.

[0005] The present disclosure was completed in light of the above circumstances, and aims to improve the productivity of fiber assemblies. [Means for solving the problem]

[0006] The nozzle head of the first disclosure comprises: A cylindrical head body having a spinning hole opening to the outer peripheral surface and a supply path for supplying a spinning solution to the spinning hole; a spinning electrode having a potential difference with a collector electrode to charge the spinning solution; A nozzle head configured to collect the spinning solution discharged from the radiation hole to the outside of the head body in a state where it is converted into ultrafine fibers by electrostatic force, The surface roughness of the opening edge of the radiation hole on the outer peripheral surface of the head body is greater than the surface roughness of the inner peripheral surface of the head body.

[0007] The electrospinning apparatus of the second disclosure comprises: A nozzle head; a collector electrode; The nozzle head is A cylindrical head body having a spinning hole opening to the outer peripheral surface and a supply path for supplying a spinning solution to the spinning hole; a spinning electrode having a potential difference between itself and the collector electrode and charging the spinning solution; The surface roughness of the opening edge of the radiation hole on the outer peripheral surface of the head body is greater than the surface roughness of the inner peripheral surface of the head body, The spinning solution discharged from the spinning holes to the outside of the head body is converted into ultrafine fibers by electrostatic force and collected by a collecting member. [Effects of the Invention]

[0008] According to the nozzle head of the first disclosure and the electrospinning device of the second disclosure, it is possible to improve the productivity of the fiber aggregate produced by collecting ultrafine fibers in a collecting member. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view showing an outline of an electrospinning apparatus according to the first embodiment. [Figure 2] FIG. 2 is a side view showing an outline of the electrospinning apparatus. [Figure 3] FIG. 3 is a plan view in which a part of the nozzle head is omitted. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 5 is an enlarged cross-sectional view taken along line BB in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Here, preferred embodiments of the present invention will be described. Any combination of the following embodiments, provided that no contradiction occurs, is also included in the embodiments of the present invention.

[0011] (1) The nozzle head of the first disclosure includes a cylindrical head body having a spinning hole opening to its outer peripheral surface and a supply path for supplying the spinning solution to the spinning hole, and a spinning electrode having a potential difference with a collector electrode and charging the spinning solution. The nozzle head is configured to collect the spinning solution discharged from the spinning hole to the outside of the head body in a state of being converted into ultrafine fibers by electrostatic force in a collecting member. The surface roughness of the opening edge of the spinning hole on the outer peripheral surface of the head body is greater than the surface roughness of the inner peripheral surface of the head body.

[0012] In this nozzle head, the surface roughness of the opening edge of the spinning hole on the outer peripheral surface of the head body is greater than the surface roughness of the inner peripheral surface of the head body, so that the surface free energy between the opening edge of the spinning hole on the outer peripheral surface of the head body and the spinning solution is relatively small. Therefore, even if the surface tension of the spinning solution is low, the wettability of the spinning solution at the opening edge of the spinning hole is low, and the spinning solution is easily separated from the outer peripheral surface of the head body. As a result, the amount of ultrafine fibers collected by the collecting member increases, and the productivity of the fiber aggregate produced by collecting ultrafine fibers on the collecting member is improved.

[0013] (2) In (1), it is preferable that the surface roughness of the opening edge of the radiation hole on the outer peripheral surface of the head body is greater than the surface roughness of the region other than the opening edge of the radiation hole. According to this configuration, it is possible to reduce the cost required for surface treatment to increase the surface roughness of the outer peripheral surface of the head body.

[0014] (3) In (1) or (2), the surface roughness of the inner circumferential surface of the spinning hole may be greater than the surface roughness of the inner circumferential surface of the head body. With this configuration, even if the surface tension of the spinning solution is low, the wettability of the spinning solution on the inner circumferential surface of the spinning hole is low, and the spinning solution easily passes through the spinning hole.

[0015] (4) In (3), the surface roughness of the inner circumferential surface of the radiation hole may be greater than the surface roughness of the opening edge portion of the radiation hole on the outer circumferential surface of the head body. This configuration can prevent the spinning solution from remaining attached to the inner circumferential surface of the radiation hole.

[0016] (5) In (1) or (2), the surface roughness Ra of the opening edge of the spinning hole on the outer peripheral surface of the head body is preferably 1 μm or more and less than 10 μm. With this configuration, even if the surface tension of the spinning solution is low, the wettability of the spinning solution at the opening edge of the spinning hole is low, and the spinning solution is easily separated from the outer peripheral surface of the head body.

[0017] (6) In (1) or (2), the surface roughness Rz of the opening edge of the spinning hole on the outer peripheral surface of the head body is preferably 4 μm or more and less than 40 μm. With this configuration, even if the surface tension of the spinning solution is low, the wettability of the spinning solution at the opening edge of the spinning hole is low, and the spinning solution is easily separated from the outer peripheral surface of the head body.

[0018] (7) In (1) or (2), the surface tension of the spinning solution is preferably 15 mN / m or more and less than 30 mN / m. This configuration can promote the spinning solution to be turned into ultrafine fibers without increasing the wettability of the spinning solution at the opening edge of the spinning hole.

[0019] (8) The electrospinning apparatus of the second disclosure includes a nozzle head and a collector electrode. The nozzle head is a member having a cylindrical head body having a spinning hole opening on its outer peripheral surface and a supply path for supplying the spinning solution to the spinning hole, and a spinning electrode that has a potential difference with the collector electrode and charges the spinning solution. The surface roughness of the opening edge of the spinning hole on the outer peripheral surface of the head body is greater than the surface roughness of the inner peripheral surface of the head body. The spinning solution discharged from the spinning hole to the outside of the head body is collected by a collecting member in a state where it has been converted into ultrafine fibers by electrostatic force. As with the nozzle head of the first disclosure, the electrospinning apparatus of the second disclosure increases the amount of ultrafine fibers collected by the collecting member, thereby improving the productivity of the fiber aggregate produced by collecting ultrafine fibers on the collecting member.

[0020] <Embodiment 1> A first embodiment of the present disclosure will be described with reference to Figures 1 to 5. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In this first embodiment, with regard to the front-to-back direction, the F direction in Figures 2 to 4 is defined as the front. With regard to the up-down direction, the H direction in Figures 1, 2, 4, and 5 is defined as the up. With regard to the left-to-right direction, the R direction in Figures 1, 3, and 5 is defined as the right.

[0021] 1 and 2 is an electrospinning apparatus 10 that spins ultrafine fibers 38 (nanofibers) from a spinning solution 31 and collects the ultrafine fibers 38 in a collecting member 11, thereby producing a fiber aggregate 14. The fiber aggregate 14 may be, for example, a nonwoven fabric used as a separator for a secondary battery (not shown).

[0022] The spinning solution 31 contains a resin material that forms the ultrafine fibers 38 as a solute, which is dissolved or dispersed in a volatile solvent. Examples of the solute include synthetic resins such as polyacrylonitrile (PAN), polypropylene (PP), and polyethylene (PE). Examples of the solvent include compounds such as N,N-dimethylacetamide (DMA), N,N-dimethylformamide (DMF), and tetrahydrofuran (THF). The surface tension of the spinning solution 31 in this embodiment 1 is 28.8 mN / m at a temperature of 25°C. The measuring device used is a DM-701 manufactured by Kyowa Interface Science Co., Ltd. The measurement method is the hanging drop method and the Young-Laplace method.

[0023] The electrospinning apparatus 10 includes a nozzle head 20, a collector electrode 17, a transport device 13 for transporting the collecting member 11, the collector electrode 17, a tank 41, a pump 43, and a DC power supply 44.

[0024] As shown in Figures 3 to 5, the nozzle head 20 includes a head body 30 and a spinning electrode 50. The head body 30 stores the amount of spinning solution 31 required for spinning and supplies the spinning solution 31 to a spinning hole 36 described later. The head body 30 has a cylindrical shape as a whole with an axis L oriented horizontally (front-rear direction). The axis L of the head body 30 is parallel to the width direction of a collection member 11 described later.

[0025] The head body 30 has a double-tube structure consisting of a cylindrical inner tube 32 and a cylindrical outer tube 33 that concentrically surrounds the inner tube 32. The inner tube 32 and the outer tube 33 are formed, for example, from a solvent-resistant resin. The solvent-resistant resin is, for example, a synthetic resin such as fluororesin (PTFE).

[0026] The internal space of the inner tube 32 functions as a first supply path 34 for storing and flowing the spinning solution 31. The space between the outer peripheral surface of the inner tube 32 and the inner peripheral surface 30B of the outer tube 33 functions as a second supply path 35 for storing and flowing the spinning solution 31. A plurality of inner holes 37 are formed at the lower end of the inner tube 32 at intervals in the direction of the axis L. The inner holes 37 penetrate the inner tube 32 in the vertical direction, and connect the first supply path 34 and the second supply path 35.

[0027] The downstream ends of two pipes 42 are connected to the supply ports 61 at both ends of the inner pipe 32, respectively. For convenience, only one of the two pipes 42 is shown in Fig. 1. The upstream end of the pipe 42 is connected to a tank 41 in which the spinning solution 31 is stored. A pump 43 is provided in the middle of the pipe 42 to pressure-feed the spinning solution 31 in the tank 41 to the nozzle head 20.

[0028] A plurality of radiation holes 36 are formed at the upper end of the outer tube 33 at intervals in the direction of the axis L. The radiation holes 36 penetrate the outer tube 33 in the vertical direction, and connect the second supply passage 35 to the outside of the head main body 30 (outer tube 33). In a plan view of the nozzle head 20 seen from above, the radiation holes 36 are circular. The inner diameter of the radiation holes 36 is preferably 0.5 mm to 2.0 mm, for example, 1.0 mm.

[0029] In this embodiment 1, the annular region of the outer peripheral surface 30A of the head body 30 that concentrically surrounds each radiation hole 36 is defined as the opening edge 36E of the radiation hole 36. The surface roughness of the opening edge 36E of the radiation hole 36 is greater than the surface roughness of the inner peripheral surface 30B of the head body 30. That is, the opening edge 36E of the outer peripheral surface 30A of the outer tube 33 is subjected to a surface treatment process to increase the surface roughness. The inner peripheral surface 30B of the outer tube 33 is not subjected to a surface treatment process to increase the surface roughness. In this embodiment 1, the outer peripheral surface 30A of the head body 30 is synonymous with the outer peripheral surface of the outer tube 33. The inner peripheral surface 30B of the head body 30 is synonymous with the inner peripheral surface of the outer tube 33.

[0030] The surface roughness Ra of the opening edge 36E of the radiation hole 36 is 1 μm or more and less than 10 μm, and the surface roughness Ra of the inner circumferential surface 30B of the outer tube 33 is 0.05 μm or more and less than 0.25 μm. The surface roughness Ra is the arithmetic mean roughness according to [JIS B 0601:2013]. The surface roughness Rz of the opening edge 36E of the radiation hole 36 is 4 μm or more and less than 40 μm, and the surface roughness Rz of the inner circumferential surface 30B of the outer tube 33 is 0.2 μm or more and less than 1 μm. The surface roughness Rz is the maximum height roughness according to [JIS B 0601:2013].

[0031] The region of the outer peripheral surface 30A of the head main body 30 (outer tube 33) other than the opening edge portion 36E is defined as the general region 30G. The general region 30G is not subjected to a surface treatment process to increase the surface roughness. Therefore, the surface roughness of the general region 30G is smaller than the surface roughness of the opening edge portion 36E of the radiation hole 36. Specifically, the surface roughness Ra of the general region 30G of the outer tube 33 is 0.05 μm or more and less than 0.25 μm. The surface roughness Rz of the general region 30G of the outer tube 33 is 0.2 μm or more and less than 1 μm. In this embodiment 1, the general region 30G of the outer peripheral surface 30A of the head main body 30 is synonymous with the region of the outer peripheral surface of the outer tube 33 other than the opening edge portion 36E.

[0032] The surface roughness of the inner circumferential surface 36S of the radiation hole 36 is greater than the surface roughness of the opening edge portion 36E of the radiation hole 36 and greater than the surface roughness of the inner circumferential surface 30B of the head body 30. Specifically, the surface roughness Ra of the inner circumferential surface 36S of the radiation hole 36 is 1 μm or more and less than 10 μm. The surface roughness Rz of the inner circumferential surface 36S of the radiation hole 36 is 4 μm or more and less than 40 μm.

[0033] The spinning electrode 50 has a diameter smaller than the inner diameter of the inner tube 32 and is made of a conductive wire (wire-shaped member) made of a metal such as stainless steel. The wire diameter of the spinning electrode 50 is, for example, 0.9 mm. The spinning electrode 50 is housed in the head body 30 and is formed into a spiral shape (coil shape) centered on the axis L of the head body 30. The spinning electrode 50 is entirely immersed in the spinning solution 31 in the head body 30. That is, the entire outer surface of the spinning electrode 50 is in contact with the spinning solution 31 in the head body 30. The spinning electrode 50 is housed in the second supply path 35 and arranged along the inner surface 30B of the outer tube 33. The spiral pitch of the spinning electrode 50 is the same as the pitch in the front direction of the spinning holes 36. The spinning electrode 50 has a shape that passes through all the spinning holes 36 in a plan view. The spinning electrode 50 is connected to a DC power source 44 via a wire 45 at the end of the outer tube 33 .

[0034] The conveying device 13 is a device for conveying the capturing material 11 horizontally (left-right) above the nozzle head 20. The capturing material 11 is a long, sheet-like member. The conveying device 13 is configured to include a feed roller 12 and a take-up roller 15, which are arranged at the same height and spaced apart in the left-right direction. The capturing material 11 is wound around the feed roller 12. The leading end of the capturing material 11 in the conveying direction is wound around the take-up roller 15. In the spinning process, the capturing material 11 wound around the feed roller 12 is wound around the take-up roller 15 while moving horizontally (rightward) between the rollers 12 and 15.

[0035] The collector electrode 17 is disposed between the delivery roller 12 and the take-up roller 15. The collector electrode 17 is disposed along the upper surface of the collection region 16 of the collection member 11, which is stretched horizontally between the rollers 12 and 15. The positive electrode of the DC power supply 44 is connected to the spinning electrode 50, and the negative electrode is connected to the collector electrode 17.

[0036] Next, a method for producing the fiber aggregate 14 will be described. The first supply path 34 and the second supply path 35 of the nozzle head 20 are filled with the spinning solution 31. When the electrospinning device 10 is operated, the collecting member 11 is sent horizontally at a constant speed from the delivery roller 12 to the take-up roller 15 while being in contact with or close to the lower surface of the collector electrode 17. By driving the pump 43, the spinning solution 31 in the tank 41 is supplied to the first supply path 34 of the inner tube 32, passes through the inner hole 37, and is supplied to the second supply path 35. The second supply path 35 functions as a buffer space for the spinning solution 31 discharged from the inner hole 37.

[0037] The spinning solution 31 in the second supply path 35 is sprayed from the spinning hole 36 by an electrostatic force (Coulomb force) caused by the potential difference between the spinning electrode 50 and the collector electrode 17 and is attracted to the collector electrode 17. At the opening edge 36E of the spinning hole 36 on the outer peripheral surface 30A of the outer tube 33, the greater the surface free energy of the outer tube 33, the more easily the spinning solution 31 wets, and the greater the amount of spinning solution 31 that adheres to the opening edge 36E without being attracted to the collector electrode 17. In view of this point, in this embodiment 1, a surface treatment process is performed on the opening edge 36E to increase the surface roughness, and the surface roughness of the opening edge 36E is made larger than the surface roughness of the inner peripheral surface 30B of the outer tube 33. The larger the surface roughness, the less the effect of the surface free energy of the outer tube 33 on the wettability of the spinning solution 31, and the more difficult it is for the spinning solution 31 to wet. Therefore, the amount of the spinning solution 31 that remains attached to the opening edge 36E is reduced, and the amount of the spinning solution 31 that is sprayed from the spinning hole 36 toward the collector electrode 17 is increased.

[0038] The spinning solution 31 sprayed from the spinning holes 36 is charged by contact with the spinning electrode 50, and therefore, in the process of rising from the nozzle head 20 toward the collection member 11, the spinning solution 31 becomes ultrafine fibers 38 due to the repulsive force of the charges accumulated in the spinning solution 31. Since the surface area of ​​the ultrafine fibers 38 is large compared to their volume, the solvent in the ultrafine fibers 38 evaporates efficiently. Furthermore, this evaporation reduces the volume of the ultrafine fibers 38, and the charge density becomes higher. Therefore, the repulsive force between the charged ultrafine fibers 38 increases, and each ultrafine fiber 38 splits into even thinner ultrafine fibers 38.

[0039] Through this process, ultrafine fibers 38 are spun and collected on the lower surface of the collecting member 11, thereby forming a fiber aggregate 14. The collecting member 11 on which the fiber aggregate 14 is layered is taken up by a take-up roller 15. When using the fiber aggregate 14, the collecting member 11 is pulled out from the take-up roller 15, and the fiber aggregate 14 is peeled off from the collecting member 11.

[0040] As described above, in the present embodiment 1, the surface roughness of the opening edge 36E is increased to reduce the effect of the surface free energy of the outer tube 33 on the wettability of the spinning solution 31, so that even if the surface tension of the spinning solution 31 is low, it is possible to reduce the amount of the spinning solution 31 adhering to the opening edge 36E. The smaller the surface tension of the spinning solution 31, the more easily the spinning solution 31 turns into ultrafine fibers 38, so that the ultrafine fibers 38 are less likely to form a film in the collecting member 11. Therefore, a good fiber aggregate 14 can be obtained.

[0041] The electrospinning apparatus 10 of this embodiment 1 includes a nozzle head 20, a collector electrode 17, and a collecting member 11. The nozzle head 20 has a cylindrical head body 30 and a spinning electrode 50. The head body 30 has a spinning hole 36 opening on the outer peripheral surface 30A and a supply path for supplying the spinning solution 31 to the spinning hole 36. The spinning electrode 50 has a potential difference with the collector electrode 17, and charges the spinning solution 31. The nozzle head 20 is configured to collect the spinning solution 31 discharged from the spinning hole 36 to the outside of the head body 30 in a state where it is converted into ultrafine fibers 38 by electrostatic force on the collecting member 11. The surface roughness of the opening edge portion 36E of the spinning hole 36 on the outer peripheral surface 30A of the head body 30 is greater than the surface roughness of the inner peripheral surface 30B of the head body 30.

[0042] The smaller the surface tension of the spinning solution 31, the easier it is for the spinning solution 31 to be turned into ultrafine fibers 38, but the surface free energy of the head body 30 makes it easier for the spinning solution 31 to remain on the outer peripheral surface 30A of the head body 30. In view of this, the surface roughness of the opening edge 36E of the spinning hole 36 on the outer peripheral surface 30A of the head body 30 is made larger than the surface roughness of the inner peripheral surface 30B of the head body 30. As a result, the surface free energy between the opening edge 36E of the spinning hole 36 and the spinning solution 31 on the outer peripheral surface 30A of the head body 30 is relatively small. Therefore, even if the surface tension of the spinning solution 31 is small, the wettability of the spinning solution 31 at the opening edge 36E of the spinning hole 36 is low, and the spinning solution 31 is easily separated from the outer peripheral surface 30A of the head body 30. This increases the amount of ultrafine fibers 38 captured by the capturing member 11, thereby improving the productivity of the fiber aggregate 14 produced by capturing the ultrafine fibers 38 in the capturing member 11.

[0043] On the outer peripheral surface 30A of the head body 30, the surface roughness of the opening edge 36E of the radiation hole 36 is greater than the surface roughness of the area other than the opening edge 36E of the radiation hole 36. According to this configuration, the cost required for surface treatment to increase the surface roughness of the outer peripheral surface 30A of the head body 30 can be reduced.

[0044] The surface roughness of the inner circumferential surface 36S of the spinning hole 36 is greater than the surface roughness of the inner circumferential surface 30B of the head body 30. According to this configuration, even if the surface tension of the spinning solution 31 is small, the wettability of the spinning solution 31 on the inner circumferential surface 36S of the spinning hole 36 is low, and the spinning solution 31 easily passes through the spinning hole 36.

[0045] The surface roughness of the inner circumferential surface 36S of the radiation hole 36 is greater than the surface roughness of the opening edge portion 36E of the radiation hole 36 on the outer circumferential surface 30A of the head body 30. According to this configuration, it is possible to prevent the spinning solution 31 from remaining attached to the inner circumferential surface 36S of the radiation hole 36.

[0046] The surface roughness Ra of the opening edge 36E of the spinning hole 36 on the outer peripheral surface 30A of the head body 30 is 1 μm or more and less than 10 μm. The surface roughness Ra is preferably 5 μm or more and less than 10 μm, and more preferably 8 μm or more and less than 10 μm. According to this configuration, even if the surface tension of the spinning solution 31 is low, the wettability of the spinning solution 31 on the opening edge 36E of the spinning hole 36 is low, and the spinning solution 31 is easily separated from the outer peripheral surface 30A of the head body 30.

[0047] The surface roughness Rz of the opening edge 36E of the spinning hole 36 on the outer peripheral surface 30A of the head body 30 is 4 μm or more and less than 40 μm. The surface roughness Rz is preferably 20 μm or more and less than 40 μm, and more preferably 32 μm or more and less than 40 μm. According to this configuration, even if the surface tension of the spinning solution 31 is small, the wettability of the spinning solution 31 on the opening edge 36E of the spinning hole 36 is low, and the spinning solution 31 is easily separated from the outer peripheral surface 30A of the head body 30.

[0048] The surface tension of the spinning solution 31 is 15 mN / m or more and less than 30 mN / m. The surface tension is preferably 15 mN / m or more and 25 mN / m, and more preferably 15 mN / m or more and less than 20 mN / m. This configuration can promote the formation of the spinning solution 31 into the ultrafine fibers 38 without increasing the wettability of the spinning solution 31 at the opening edge 36E of the spinning hole 36.

[0049] <Other Examples> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention. The surface roughness of the inner circumferential surface of the radiation hole may be the same as the surface roughness of the inner circumferential surface of the head body. The entire outer circumferential surface of the head body may be set to the same surface roughness. The surface roughness of the opening edge of the radiation hole may be greater than the surface roughness of the inner peripheral surface of the radiation hole, or may be the same as the surface roughness of the inner peripheral surface of the radiation hole. The supply path of the head main body is not limited to a double-tube structure, and may be formed of only one tube. [Explanation of symbols]

[0050] 10...Electrospinning device 14...Collection member 17...Collector electrode 20...Nozzle head 30...Head body 30A...Outer surface of head body 30B...Inner surface of head body 31...Spinning solution 34…1st supply route (supply route) 35…Second supply route (supply route) 36...Spinning hole 36S...Inner surface of spinning hole 36E...Opening edge of spinning hole 38...Ultrafine fiber 50...Spinning electrode

Claims

1. A cylindrical head body having a spinning hole opening to the outer peripheral surface and a supply path for supplying a spinning solution to the spinning hole; a spinning electrode having a potential difference with a collector electrode to charge the spinning solution; A nozzle head configured to collect the spinning solution discharged from the radiation hole to the outside of the head body in a state where it is converted into ultrafine fibers by electrostatic force, A nozzle head in which the surface roughness of the opening edge of the radiation hole on the outer peripheral surface of the head body is greater than the surface roughness of the inner peripheral surface of the head body.

2. The nozzle head according to claim 1, wherein, on the outer peripheral surface of the head body, the surface roughness of the opening edge portion of the radiation hole is greater than the surface roughness of an area other than the opening edge portion of the radiation hole.

3. The nozzle head according to claim 1 or 2, wherein the surface roughness of the inner circumferential surface of the radiation hole is greater than the surface roughness of the inner circumferential surface of the head body.

4. The nozzle head according to claim 3, wherein the surface roughness of the inner surface of the radiation hole is greater than the surface roughness of the opening edge portion of the radiation hole on the outer peripheral surface of the head body.

5. The nozzle head according to claim 1 or 2, wherein the surface roughness Ra of the opening edge portion of the radiation hole on the outer peripheral surface of the head body is 1 μm or more and less than 10 μm.

6. The nozzle head according to claim 1 or 2, wherein the surface roughness Rz of the opening edge portion of the radiation hole on the outer peripheral surface of the head body is 4 μm or more and less than 40 μm.

7. 3. The nozzle head according to claim 1, wherein the surface tension of the spinning solution is 15 mN / m or more and less than 30 mN / m.

8. A nozzle head; a collector electrode; The nozzle head is A cylindrical head body having a spinning hole opening to the outer peripheral surface and a supply path for supplying a spinning solution to the spinning hole; a spinning electrode having a potential difference between itself and the collector electrode and charging the spinning solution; The surface roughness of the opening edge of the radiation hole on the outer peripheral surface of the head body is greater than the surface roughness of the inner peripheral surface of the head body, The spinning solution discharged from the spinning holes to the outside of the head body is converted into ultrafine fibers by electrostatic force and collected in a collecting member.

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