Nozzle block equipped with cleaning means and electrospinning device equipped with the same

Abstract

The present invention relates to a nozzle block applied to an electrospinning apparatus, and is characterized in that it includes at least one piercing means having a diameter smaller than the inner diameter of the spinning nozzle and arranged coaxially inside the spinning nozzle to prevent a solution from solidifying at the tip of the spinning nozzle, and a first cleaning mechanism for piercing the plug at the tip of the spinning nozzle by moving the piercing means and the spinning nozzle back and forth relative to each other to clean the spinning nozzle, and a second cleaning mechanism for cleaning aggregates deposited around the tip and outside of the spinning nozzle by chemical and / or physical cleaning after the electrospinning process is temporarily interrupted or completed.

Description

[Technical Field]

[0001] The present invention relates to an electrospinning device, and more particularly to a nozzle block having various cleaning means for cleaning a spinning nozzle of an electrospinning device when the nozzle is clogged or contaminated due to solidification of a polymer material, and an electrospinning device having such a nozzle block.

[0002] This application claims priority based on Korean Patent Application No. 10-2021-0179169, filed on December 14, 2021, and the entire contents disclosed in the specification and drawings of that application are incorporated herein by reference. [Background technology]

[0003] The electrospinning process is a process of producing nanofibers in an electric field environment by applying a high DC voltage of several thousand to several tens of thousands of volts to a solution and connecting a collector to ground or negative voltage.

[0004] This electrospinning process is typically implemented using an electrospinning apparatus. Electrospinning apparatuses are divided into bottom-up electrospinning apparatuses, in which a collector is located below the spray nozzle, and top-up electrospinning apparatuses, in which a collector is located above the spray nozzle. However, with the bottom-up electrospinning apparatus, agglomerated residues that solidify and are generated at the tip of the spinning nozzle during the spinning process fall into the lower accumulation area where the nanofibers are stacked, limiting the production of high-quality nanofiber webs. Therefore, due to these issues, top-up electrospinning apparatuses are primarily used for electrospinning processes for mass-producing nanofibers.

[0005] The spinning nozzle used to produce nanofibers is a nozzle consisting of a capillary-type needle. During the electrospinning process, nozzle clogging does not occur when the solution is continuously ejected. However, when the process is temporarily stopped, the nozzle becomes clogged due to the solution solidifying due to solvent evaporation at the tip of the nozzle, making it difficult to proceed to the next process. This phenomenon frequently occurs in the process of producing nanofibers from a solution prepared using a highly volatile solvent.

[0006] For example, when producing poly(vinylidene fluoride (PVDF)) nanofibers using electrospinning, the PVDF solution is made using a mixture of dimethylacetamide (DMAc) and acetone with a high acetone ratio to increase the solvent evaporation rate. In this case, the acetone ratio is set to a range of 50% to 90% to produce nanofibers.

[0007] However, as the proportion of acetone increases, the solvent volatility increases, increasing the frequency of agglomerates forming at the nozzle tip. In particular, when using polymers for biotechnology, which use highly volatile solvents, there is a problem of nozzle clogging when the process is temporarily interrupted.

[0008] On the other hand, polycaprolactone (PCL) / acetic acid solution, polylactic acid (PLA) / dichrolomethane solution, silk / formic acid solution, and nylon / formic acid solution have the problem of frequent clogging of the nozzle tip due to the rapid evaporation of the solvent.

[0009] When the electrospinning nanofiber manufacturing process is temporarily suspended, various research and development efforts have been made to solve the problem of the nozzle discharging the spinning solution becoming clogged due to the solidification of the polymeric material.

[0010] Patent Document 1 (Korean Patent Publication No. 10-1178171) relates to a nozzle block for preventing nozzle clogging and contamination and an upward-direction electrospinning apparatus including the same, which is characterized by having an anti-solidification solution container that completely immerses the spray nozzle in an anti-solidification solution to prevent the solvent contained in the spinning solution from evaporating from the end of the spray nozzle when the spraying operation from the spray nozzle is interrupted during the electrospinning process, and recovers the anti-solidification solution when the spraying operation of the spinning solution from the spray nozzle is resumed. This prevents the nozzle from being clogged or contaminated even when the nanofiber manufacturing process is temporarily interrupted.

[0011] Patent Document 2 (Korean Patent Publication No. 10-2025159) discloses an electrospinning nozzle device including a needle-shaped wire stopper for needle insertion that is insertable into a capillary needle of a spinning nozzle to prevent solidification of the solution at the tip of the spinning nozzle, and a cleaning spray nozzle that sprays a solvent onto the tip of the spinning nozzle to remove deposits. Patent Document 2 describes that when the electrospinning process is interrupted, the needle-shaped wire stopper for needle insertion is moved forward of the capillary needle of the spinning nozzle and inserted into the capillary needle, preventing clogging of the nozzle tip. After the needle-shaped wire stopper for needle insertion is separated from the capillary needle of the spinning nozzle, the cleaning spray nozzle performs a cleaning process by spraying a solvent onto the tip of the capillary needle to remove deposits.

[0012] As a result, Patent Document 2 prevents the solution from solidifying at the tip of the spinning nozzle when the electrospinning process is interrupted, and allows the electrospinning process to be performed stably without clogging the nozzle in the subsequent process.

[0013] In addition, Patent Document 3 (Korean Patent Publication No. 10-2176015) proposed by the present inventor proposes a nozzle block equipped with a nozzle clogging prevention means including a piercing means having a diameter smaller than that of the spinning needle and at least one of which is coaxially arranged inside the spinning needle, and a reciprocating mechanism for reciprocating the piercing means and the spinning needle relative to each other. According to Patent Document 3, even if the electrospinning process is temporarily interrupted, it is possible to prevent the solution from solidifying at the tip of the spinning nozzle or clogging of the spinning nozzle due to external contaminants. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Korean Patent Registration No. 10-1178171 [Patent Document 2] Korean Patent Registration No. 10-2025159 [Patent Document 3] Korean Patent Registration No. 10-2176015 Summary of the Invention [Problem to be solved by the invention]

[0015] The first technical objective of the present invention is to prevent the solution from solidifying at the tip of the spinning nozzle or the spinning nozzle from being clogged by external contaminants even if the electrospinning process is temporarily interrupted.

[0016] A second technical object of the present invention is to clean the spinning nozzle by thoroughly washing and removing the spinning agglomerates deposited around the tip and outside of the spinning nozzle. [Means for solving the problem]

[0017] To achieve the above technical objectives, a nozzle block applicable to electrospinning as a first preferred aspect of the invention includes a spinning nozzle including a plurality of hollow spinning needles for discharging a spinning solution to the outside, a piercing means having a diameter smaller than the spinning needles and arranged coaxially with the spinning needles, at least one rotating brush arranged on the left and / or right side of each of the spinning needles and rotating to clean the outside of the spinning needles, and a reciprocating driving means for moving the piercing means and the spinning needles back and forth relative to each other, characterized in that by moving the piercing means and the spinning needles back and forth relative to each other, clogging at the tips of the spinning needles is pierced and agglomerates deposited on the outside of the tips of the spinning needles are cleaned using the at least one rotating brush.

[0018] Another embodiment of the nozzle block of the present invention according to the first aspect is characterized in that it further includes a cleaning nozzle having an inner diameter larger than the outer diameter of the spinning needle, arranged to coaxially surround the spinning needle, and equipped with a cleaning needle that cleans the tip of the spinning needle by ejecting a cleaning solution.

[0019] Another embodiment of the nozzle block of the present invention according to the first aspect is characterized in that it further comprises a rotation driving means for linearly reciprocating the rotary brush around the spinning needle and rotating the rotary brush around a central axis.

[0020] In another embodiment of the nozzle block of the present invention according to the first aspect, the rotating brush is a brush in which a roll brush is attached to a round bar or a brush in which a tail comb is attached to a round bar.

[0021] Another embodiment of the nozzle block of the present invention according to the first aspect is characterized in that it further includes a hollow guide needle that is arranged below and spaced a certain distance from the spinning needle in the coaxial direction to guide the piercing means to accurately enter the inside of the spinning needle without error, and has an inner diameter and an outer diameter that are equal to or larger than those of the spinning needle.

[0022] In another embodiment of the nozzle block according to the first aspect of the present invention, the distance between the spinning needle and the guide needle is 1 mm to 10 mm.

[0023] In another embodiment of the nozzle block of the present invention according to the first aspect, the piercing means is arranged coaxially inside the guide needle, and the tip of the piercing means is located at the same position as the tip of the guide needle or within 5 mm below.

[0024] In another embodiment of the nozzle block of the present invention according to the first aspect, the diameter of the piercing means is smaller than the inner diameter of the spinning needle by 0.005 mm to 1 mm.

[0025] In another embodiment of the nozzle block of the present invention according to the first aspect, the piercing means is a wire having a diameter smaller than the inner diameter of the spinning needle, or a hollow piercing needle having an outer diameter smaller than the inner diameter of the spinning needle.

[0026] In another embodiment of the nozzle block of the present invention according to the first aspect, the reciprocating drive means is a pneumatic drive device for reciprocating the piercing needle up and down relative to the spinning needle.

[0027] In another embodiment of the nozzle block of the present invention according to the first aspect, the cleaning needle has an inner diameter that is 0.1 mm to 5 mm larger than the outer diameter of the spinning needle.

[0028] In another embodiment of the nozzle block of the present invention according to the first aspect, the cleaning needle is arranged coaxially with the tip of the spinning needle and 0.1 mm to 5 mm below the tip.

[0029] In another embodiment of the nozzle block according to the first aspect of the present invention, the at least one rotating brush is a pair of rotating brushes arranged at a predetermined distance from each other on the left and right sides of the tip of the spinning needle.

[0030] In another embodiment of the nozzle block of the present invention according to the first aspect, the piercing needle is raised so that the protruding length of the piercing needle is 0.5 mm to 20 mm.

[0031] Another embodiment of the nozzle block of the present invention according to the first aspect further includes a first nozzle support member for supporting and fixing at least two or more of the spinning needles in a row, a second nozzle support member for supporting and fixing at least two or more of the guide needles in a row so as to correspond to the spinning needles fixed to the first nozzle support member, and a third nozzle support member for supporting and fixing at least two or more of the piercing needles in a row so as to be guided inside the guide needles fixed to the second nozzle support member.

[0032] Another embodiment of the nozzle block of the present invention according to the first aspect is characterized in that it further includes a fourth nozzle support member for supporting and fixing at least two or more cleaning needles arranged in a row so as to coaxially surround at least a portion of the tip of the spinning needle.

[0033] An electrospinning apparatus as a second preferred aspect of the invention for achieving the above technical object includes an unwinding unit that unwinds a roll on which a substrate is wound for spinning a spinning solution to laminate nanofibers, a winding unit that winds up the substrate on which the nanofibers are laminated, a nozzle block having the features of the first aspect or various embodiments of the first aspect described above, a collector that laminates the nanofibers spun from the nozzle block while transporting the substrate, a solution storage tank that stores the spinning solution, a solution transfer device that transfers the solution from the solution storage tank to the nozzle block, and a high-voltage power supply device that applies a high voltage to the spinning solution discharged from the spinning needle of the nozzle block.

[0034] Another embodiment of the electrospinning apparatus according to the second aspect further includes a robot driving unit for driving the nozzle block back and forth in the width direction of the substrate, and a spinning distance adjusting unit for adjusting the distance between the collector and the tip of the spinning needle.

[0035] Another embodiment of the electrospinning apparatus according to the second aspect further includes a hot air generator for volatilizing the solvent from a large amount of spun filaments spun from the spinning needles of the nozzle block to produce fine nanofibers, a humidity controller for controlling the internal humidity to control the solvent evaporation rate, and a lamination device for adjusting the bonding state of the nanofibers formed on the substrate.

[0036] Another embodiment of the electrospinning apparatus according to the second aspect further includes a video camera for monitoring in real time the solidification or clogging state of the spinning solution formed at the tip of the spinning needle or the droplet state of a Taylor cone formed at the tip of the spinning needle.

[0037] Another embodiment of the electrospinning apparatus according to the second aspect further includes collection guide units disposed on the left and right sides of the nozzle block to deposit the spun nanofibers in a limited area of ​​the collector. [Effects of the Invention]

[0038] According to the present invention, even if the nanofiber production process is temporarily interrupted, the phenomenon of the spinning nozzle being clogged can be prevented, so that, first, the nanofiber production process can be continuously restarted, and second, the labor and cost required for nozzle replacement can be significantly reduced compared to the conventional method.

[0039] In addition, by using chemical and physical cleaning means to thoroughly clean away solidified materials and contaminants that have accumulated on the outside of the tip of the spray nozzle, it is possible to produce a high-quality nanofiber laminated web or membrane, and it is possible to continuously mass-produce nanofibers without interrupting the process.

[0040] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention, so the present invention should not be interpreted as being limited to the matters described in the drawings. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is an exploded perspective view of a nozzle block according to a preferred embodiment of the present invention; [Figure 2] 1 is an assembled perspective view of a nozzle block according to a preferred embodiment of the present invention; [Figure 3] FIG. 10 is a needle arrangement diagram showing the relative arrangement of needles before a piercing operation. [Figure 4] FIG. 10 is a needle arrangement diagram showing the relative positional relationship between the needles after the piercing operation. [Figure 5] FIG. 10 is a needle layout diagram showing the relative placement of needles to one another during a solvent cleaning operation. [Figure 6] 1A is a side view, FIG. 1B is a front view, and FIG. 1C is a perspective view of a rotary brush according to the present invention. [Figure 7] 1 is a diagram illustrating a downward-type roll-to-roll electrospinning apparatus according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0042] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The embodiments of the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the following embodiments. The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Although specific terms are used in the drawings and description of the present invention, these terms are used solely for the purpose of describing the present invention and are not intended to limit the meaning or the scope of the present invention as described in the claims. Therefore, those skilled in the art should understand that various modifications and equivalent embodiments are possible. Therefore, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

[0043] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, which are not drawn to scale and in which like element numbers refer to like components throughout the drawings.

[0044] The present invention includes a first cleaning mechanism that cleans the spinning nozzle by piercing clogs at the tip of the spinning nozzle by coaxially arranging at least one piercing means having a diameter smaller than the inner diameter of the spinning nozzle and moving the piercing means and the spinning nozzle back and forth relative to each other to prevent solidification of the solution at the tip of the spinning nozzle even when the electrospinning process is temporarily interrupted, and a second cleaning mechanism that cleans agglomerates that have accumulated around and outside the tip of the spinning nozzle by chemical and / or physical cleaning after the electrospinning process is temporarily interrupted or completed.

[0045] The first cleaning mechanism is achieved by coaxially arranging a piercing means having a diameter smaller than the inner diameter of the spinning nozzle inside the spinning nozzle, and the second cleaning mechanism includes a chemical cleaning mechanism characterized by coaxially arranging a cleaning solution spray nozzle having an inner diameter larger than the outer diameter of the spinning nozzle outside the spinning nozzle, and a physical cleaning mechanism characterized by arranging at least one rotating brush on the left and / or right side of the tip of the spinning nozzle.

[0046] The piercing means may be a nozzle having the same shape as the spinning nozzle, or may be a wire or needle having a small diameter, and the cleaning liquid injection nozzle may be a nozzle or needle having the same shape as the spinning nozzle.

[0047] The present invention also includes a first driving means for reciprocating the piercing means relative to the spinning nozzle, and a second driving means for reciprocating or rotating the brush relative to the spinning nozzle.

[0048] The first and second driving means may be passively driven devices such as springs or handles, or may be automatically driven devices using motors or air pressure.

[0049] Hereinafter, various embodiments and modifications for specifically realizing the technical solution principle of the present invention will be described in detail with reference to the drawings.

[0050] FIG. 1 is an exploded perspective view of a nozzle block according to a preferred embodiment of the present invention, and FIG. 2 is an assembled perspective view of the nozzle block according to a preferred embodiment of the present invention.

[0051] 1 and 2, a nozzle block 100 for an electrospinning apparatus according to a preferred embodiment of the present invention includes a spinning nozzle unit 110 having a plurality of spinning needles 111a for storing a spinning solution flowing from a solution reservoir and spinning the solution to the outside, and a plurality of piercing needles 111a arranged coaxially with the spinning needles 111a and having a diameter smaller than the inner diameter of the spinning needles 111a. a piercing unit 120 having a piercing needle 121a; a first driving unit 130 for reciprocating the piercing unit 120 up and down relative to the spinning nozzle unit 100; a first cleaning unit 140 (see FIG. 5) for chemically cleaning the spinning needle 111a by spraying a cleaning solution (cleaning solvent) onto the outside of the tip of the spinning needle 111a; a second cleaning unit 150 for physically wiping the outside of the tip of the spinning needle 111a by arranging at least one rotating brush 151, 152 around the left and / or right sides of the tip of the spinning needle 111a; and a second driving unit 155 for linearly reciprocating or rotating the rotating brushes 151, 152 relative to the spinning needle 111a.

[0052] The spinning nozzle unit 110 includes an upper nozzle body 112 and a lower nozzle body 113 coupled together to form a single body, forming an internal space in which the spinning solution flowing from a solution reservoir is stored. A solution inlet 116 may be formed in the upper nozzle body 112 or the lower nozzle body 113. The upper nozzle body 112 and the lower nozzle body 113 may be integrally formed like a cylindrical pipe. Metal conductive parts for applying high voltage are formed inside the upper nozzle body 112 and the lower nozzle body 113.

[0053] The internal space is a space where the incoming spinning solution temporarily stays while being discharged from the spinning needles 111a, or where the spinning solution is stored when the process is interrupted. The height of the internal space is preferably 1 mm to 30 mm, more preferably 3 mm to 10 mm, when used as a retention space, and is preferably 20 mm to 500 mm when used as a storage space.

[0054] At least one spinning cartridge 111, each having a plurality of spinning needles 111a for discharging a spinning solution arranged on a spinning needle support 111b, is held in the upper nozzle body 112 in a lined-up state. A nozzle cover 114 is placed on the upper nozzle body 112 to firmly fix the spinning cartridge 111 held in the upper nozzle body 112 to the upper nozzle body 112.

[0055] The plurality of spinning needles 111a are preferably arranged in the spinning cartridge 111 at intervals of 2 mm to 50 mm, and in order to mass-produce nanofibers, it is more preferable to arrange the spinning needles 111a at intervals of 3 mm to 10 mm so that they are densely packed together.

[0056] The spinning needle 111a may be a hollow needle with an inner diameter of 0.1 mm to 2.5 mm and an outer diameter of 0.2 mm to 3 mm, or may be made of tubing. The spinning needle 111a may be made of stainless steel (SUS) or copper, or may be made of quartz, silica, or poly(etheretherketone) (PEEK). If the spinning needle 111a is made of SUS-based metal, it may be coated or wrapped with an insulating material such as polyethylene or a fluorine-based material. The spinning needle support 111b may be made of PEEK, a fluorine-based polymer (Teflon®), or conductive stainless steel (SUS). Meanwhile, forming a sleeve at the end of the spinning needle 111a may facilitate the connection or replacement of the spinning needle 111a to the spinning needle support 111b. The sleeve may be a hollow tube or a hollow screw having an external thread. The sleeve is preferably made of a flexible and elastic polymer or copper (Cu) material. For example, the sleeve is preferably made of a chemically resistant flexible material such as fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), or polytetrafluoroethylene (PTFE). A hollow tube made of a conductive polymer material containing carbon and metal components may be used to provide conductivity to the sleeve. If the sleeve is a hollow tube, its inner diameter is preferably the same as the outer diameter of the spinning needle 111a or smaller than the outer diameter of the spinning needle 111a to enhance adhesion with the spinning needle 111a. For example, the sleeve preferably has an inner diameter of 0.05 mm to 4 mm and an outer diameter of 1 mm to 5 mm.

[0057] The lower nozzle body 113 has a plurality of guide needles 113a arranged on a guide needle support 113b in one-to-one correspondence with the spinning needles 111a to guide the piercing needle 121a so that it can accurately enter the inside of the spinning needle 111a without deviation. The guide needles 113a preferably have the same inner and outer diameters as the spinning needle 111a, but larger hollow needles may also be used. The guide needles 113a are disposed below the spinning needle 111a at a predetermined distance d2, and the distance d2 is preferably 1 mm to 10 mm.

[0058] A sealing cover 115 is attached to the bottom of the lower nozzle body 113 to prevent the spinning solution remaining in the internal space from leaking out due to the separation between the guide needle 113a and the piercing needle 121a. A sealant such as a silicone O-ring that fits the diameter of the piercing needle 121a is disposed in the sealing cover 115. As a result, when the piercing needle 121a penetrates the guide needle 113a and enters the spinning needle 111a, the gap between the guide needle 113a and the piercing needle 121a is sealed by the sealant.

[0059] The piercing unit 120 includes a piercing holder 122 that holds at least one piercing cartridge 121, which has a plurality of piercing needles 121a arranged on a piercing needle support 121b.

[0060] The piercing needle 121a is a rod, hollow needle, wire, or the like having a diameter smaller than the inner diameter of the spinning needle 111a and / or the guide needle 113a. The piercing needle 121a is coaxially disposed inside the guide needle 113a, and the tip of the piercing needle 121a is preferably located flush with the tip of the guide needle 113a or positioned below it with a distance d3 of 5 mm or less. The diameter of the piercing needle 121a is preferably 0.005 mm to 1 mm smaller than the inner diameter of the spinning needle 111a.

[0061] The piercing cartridge 121 and the piercing needle 121a are made of a conductive SUS-based metal, and an external high voltage is applied to the piercing cartridge 121. As a result, the high voltage applied to the piercing cartridge 121 is applied to the spinning solution inside the spinning needle 111a through the piercing needle 121a.

[0062] The intervals between the piercing needles 121 a arranged in the piercing cartridge 121 must be the same as the intervals between the spinning needles 111 a arranged in the spinning cartridge 111 .

[0063] The first driving unit 130 is preferably a double-acting pneumatic cylinder or a single-acting pneumatic cylinder combined with a spring, which is a vertical driving device for reciprocating the piercing unit 120 up and down relative to the spinning nozzle unit 110. Of course, the first driving unit 130 includes any known vertical reciprocating driving means such as a motor or a passive handle. However, in a high-voltage environment such as the electrospinning apparatus according to the present invention, a pneumatic driving device such as the pneumatic cylinder 135 is more preferable.

[0064] The first cleaning unit 140 chemically cleans the spinning needle 111a by spraying a cleaning solution onto the outside of the tip of the spinning needle 111a. For example, referring to FIGS. 3 to 5, the first cleaning unit 140 is achieved by arranging a plurality of cleaning needles 141, each having an inner diameter 0.1 mm to 5 mm larger than the outer diameter of the spinning needle 111a, coaxially and one-to-one with the spinning needle 111a on a cleaning support 142 having an internal space for accommodating a cleaning solvent (cleaning solution) injected from the outside. As shown in FIGS. 3 to 5, the cleaning needles 141 are coaxially arranged at a low position so as to be spaced a predetermined distance d1 from the tip of the spinning needle 111a. For example, the distance d1 is preferably 0.1 mm to 5 mm. The cleaning needles 141 are made of stainless steel, poly(etheretherketone; PEEK), a fluorine-based polymer, a polyethylene-based polymer, or a polypropylene-based polymer.

[0065] Therefore, by discharging a cleaning solution around the tip of the spinning needle 111a from the cleaning needle 141, it is possible to dissolve and remove the aggregates and contaminants deposited on the tip of the spinning needle 111a. It is preferable that the cleaning support 142 is disposed closely or spaced apart from the upper part of the nozzle cover 114.

[0066] The arrangement and interaction of the spinning needle 111a, guide needle 113a, piercing needle 121a and cleaning needle 141 will be described in detail with reference to FIGS.

[0067] Fig. 3 is a needle arrangement diagram showing the relative positional relationship between the needles before the piercing operation, Fig. 4 is a needle arrangement diagram showing the relative positional relationship between the needles after the piercing operation, and Fig. 5 is a needle arrangement diagram showing the relative positional relationship between the needles during the solvent cleaning operation. In particular, Figs. 3 to 5 are diagrams conceptualizing the relative positional relationship of the needles as the electrospinning process progresses.

[0068] 3, in a double-tube needle structure in which the cleaning needle 141 coaxially surrounds the spinning needle 111a, a guide needle 113a for guiding the piercing needle 121a is disposed at a predetermined distance d2 below the coaxial bottom of the spinning needle 111a. As the electrospinning process begins, a polymer solution (spinning solution) transferred from the outside is discharged to the outside from the tip of the spinning needle 111a.

[0069] Furthermore, if the electrospinning process is temporarily interrupted, the solution may solidify at the tip of the spinning needle 111a, or external contaminants may penetrate, clogging the spinning needle 111a or causing agglomerates to adhere to the outside of the tip. In this case, as shown in FIG. 4, the first driving unit 130 is operated to raise the piercing needle 121a upward, and while being guided by the guide needle 113a, it enters the spinning needle 111a, penetrates the spinning needle 111a, and protrudes outward through the clogged tip. With the piercing needle 121a piercing the tip of the spinning needle 111a and protruding outward, the first driving unit 130 is operated in the opposite direction to lower the piercing needle 121a, causing the piercing needle 121a to return to its original position and be guided into the guide needle 113a as shown in FIG. 3. At this time, the length d4 of the piercing needle 121a that protrudes through the solid tip of the spinning needle 111a is preferably 0.5 mm to 20 mm from the tip of the spinning needle 111a.

[0070] In this way, by repeating the up and down reciprocation of the piercing needle 121a at least once by the first drive unit 130, the piercing needle 121a moves up and down based on the tip of the spinning needle 111a, piercing through clogging at the tip of the spinning needle 111a caused by solidified solution. In particular, if a cleaning solvent (cleaning liquid) is discharged from the cleaning needle 141 as shown in Figure 5 during this relative up and down reciprocation of the piercing needle 121a and the spinning needle 111a, it is possible to chemically clean away aggregates and the like adhering to the outside of the tip of the spinning needle 111a.

[0071] In the present invention, as shown in FIG. 5, in order to perform both piercing and cleaning, the spinning needle 111a, the piercing needle 121a, and the cleaning needle 141 are arranged coaxially to form a triple-tube needle structure.

[0072] These triple lumen needles preferably have the dimensions shown in Table 1 below. [Table 1]

[0073] The second cleaning unit 150 according to this embodiment is a physical cleaning tool that physically wipes the exterior of the tip of the spinning needle 111a by disposing at least one rotating brush 151, 152 on the left and / or right side of the tip of the spinning needle 111a. To this end, the present invention may further include a second driving unit 155 for linearly reciprocating the rotating brushes 151, 152 relative to the spinning needle 111a or for rotating them around round rods 151a, 152a. Figure 6 shows (a) a side view, (b) a front view, and (c) a perspective view of the rotating brush according to the present invention.

[0074] Referring to FIG. 6, the rotary brushes 151 and 152 may be formed by forming roll brushes 151b or flat tail combs 152b on round bars 151a and 152a. The spacing between the roll brushes 151b and tail combs 152b on the round bars 151a and 152a may be the same as or closer to the spacing between the spinning needles 111a. The roll brushes 151b and tail combs 152b may be made of a flexible plastic with a small diameter, and in particular, may be made of an elastic silicone or urethane material. The round bars 151a and 152a may be made of an insulating plastic or metal. The at least one rotary brush 151 and 152 according to the present invention may be disposed singly on the left or right side of the tip of the spinning needle 111a. However, a pair of rotary brushes 151 and 152 disposed on both the left and right sides of the tip of the spinning needle 111a is most preferred. In this case, the pair of rotating brushes 151, 152 may both be rotating brushes 151 with roll brushes, or both may be rotating brushes 152 with tail combs, or one may be the rotating brush 151 with roll brushes and the other may be the rotating brush 152 with tail combs.

[0075] The pair of rotating brushes 151 and 152 are disposed on either side of the spinning needle 111a at a predetermined distance from each other. When the cleaning operation begins, the pair of rotating brushes 151 and 152 move close enough to the spinning needle 111a and then rotate around the round rods 151a and 152a to wipe off any agglomerates adhering to the outside of the spinning needle 111a. If necessary, only one of the pair of rotating brushes 151 and 152 can be moved toward the spinning needle 111a to perform the cleaning operation. The rotating brushes 151 and 152 preferably rotate at a rotation speed of 5 to 500 rpm. The cleaning operation using the rotating brushes 151 and 152 is preferably performed with the piercing needle 121a protruding from the tip of the spinning needle 111a to safely maintain the spinning needle 111a.

[0076] Meanwhile, the second driving unit 155 is a driving device for linearly reciprocating the rotary brushes 151 and 152 relative to the spinning needle 111a or for rotating them around the round rods 151a and 152a, and may include a motor, a single-acting pneumatic cylinder including a spring, a double-acting pneumatic cylinder, a manual handle, etc.

[0077] FIG. 7 is a diagram showing a downward roll-to-roll electrospinning apparatus according to a preferred embodiment of the present invention.

[0078] Referring to FIG. 7, the bottom-down roll-to-roll electrospinning apparatus 400 according to the present invention includes an unwinder unit 401 as an unwinding unit for unwinding a roll on which a substrate is wound for spinning a spinning solution to laminate nanofibers, a winder unit 402 as a winding unit for winding up the substrate on which the nanofibers are laminated, a nozzle block 406 according to a preferred embodiment of the present invention having the cleaning means described above, a collector 403 for laminating the nanofibers spun from the nozzle block 406 while transporting the substrate, and a solution storage tank for storing the spinning solution.

[0079] In addition, the downward roll-to-roll electrospinning apparatus 400 of the present invention further includes a solution transfer device 410 including a plunger that pushes the solution in the solution storage tank and a solution transfer pump that operates the plunger to accurately transfer the spinning solution to the nozzle block 406; a high-voltage power supply 407 that applies a high voltage to the spinning solution to impart a (+) or (-) polarity charge to the spinning solution so that the spinning solution discharged from the spinning needle of the nozzle block 406 is turned into fine fibers having a diameter of nanometers (nm) or micrometers (μm); a robot drive unit 408 that drives the nozzle block 406 back and forth in the width direction of the substrate; a spinning distance adjustment unit 409 that adjusts the distance between the collector 403 and the tip of the spinning needle 111a; and collection guide units that are arranged on the left and right sides of the nozzle block 406 in the substrate transfer direction and that stack the spun nanofibers in a limited area on the collector 403.

[0080] The collection guide unit controls the nanofibers spun from both ends of the spinning nozzle so that they do not spread outward and accumulate them in a limited internal region of the collector 403. To this end, the collection guide unit may be supplied with a high voltage of the same polarity as the high voltage applied to the spinning solution, or may use an airflow.

[0081] The solution storage tank is made of insulating materials with excellent voltage resistance, such as polypropylene (PP), polyethylene (PE), polyetheretherketone (PEEK), MC nylon (nylon), acetal, etc. In particular, the solution storage tank is preferably made of a double structure in which the inside is made of SUS metal and the outside of the SUS metal is covered with MC nylon or PP (polypropylene). The capacity of the solution storage tank is preferably 10 ml to 3,000 ml.

[0082] The solution transfer device 410 may be modified to include a motor, a screw connected to the motor shaft, a pusher fastened to the screw to push a plunger located inside the solution storage tank, a guide rod connecting the plunger and the pusher, and a linear motion guide for smoothly converting the pusher into linear motion. The lead of the screw is 0.5 to 2 mm, preferably 1 mm. The minimum speed of the pusher moving as the screw rotates is preferably 1 μm / hour to 100 μm / hour, and the maximum speed is preferably 1 cm / minute to 20 cm / minute. The plunger moves forward inside the solution storage tank by the operation of an external motor, thereby pushing out the spinning solution. The plunger may be driven by a pneumatic compressor instead of a motor.

[0083] In addition, if the capacity of the solution storage tank is insufficient, the solution transfer pumps of the solution transfer device 410 may be arranged in parallel in two tanks (first solution transfer pump and second solution transfer pump), forming a three-way valve to transfer the spinning solution.

[0084] In addition, the downward roll-to-roll electrospinning apparatus 400 of the present invention may further include a hot air generator for volatilizing the solvent from a large amount of spun filaments spun from the spinning needles of the nozzle block 406 to produce fine nanofibers, a humidity controller for controlling the internal humidity of the electrospinning apparatus 400 to control the solvent evaporation rate, and a lamination device for adjusting the bonding state of the nanofibers formed on the substrate.

[0085] In addition, the bottom-down roll-to-roll electrospinning apparatus 400 of the present invention may further include a video camera that can monitor in real time the solidification or clogging state of the spinning solution formed at the tip of the spinning needle or the state of droplets of the Taylor cone formed at the tip of the spinning needle and save the video or image. The video camera is configured at the bottom end of the side of the nozzle block 406 and moves back and forth to check the state of the tip of the spinning needle in real time or take images.

[0086] The operation of the bottom roll-to-roll electrospinning apparatus 400 of the present invention will be described below.

[0087] The spinning solution transferred from the solution storage tank by the solution transfer device 410 is discharged from the spinning needle 111a of the nozzle block 100, 406 toward the collector 403. However, if the spinning needle 111a becomes clogged during this electrospinning process, the first driving unit 130 is operated to move the piercing needle 121a guided inside the guide needle 113a up and down relative to the spinning needle 111a, so that the piercing needle 113a pierces through the tip of the spinning needle 111a, protrudes, and then returns to its original position. This reciprocal piercing operation is repeated at least once to remove the clog from the spinning needle 111a.

[0088] In addition, to clean contaminants and solidified materials that have accumulated around the tip of the spinning needle 111a, the second driving unit 155 is operated to move at least one or more rotating brushes 151, 152 (or more preferably, a pair of rotating brushes) spaced apart on the left and / or right sides of the spinning needle 111a toward the spinning needle 111a, bringing them into close proximity, and the at least one or more rotating brushes 151, 152 are rotated around the round rods 151a, 152a, thereby performing a physical cleaning operation to clean the tip of the spinning needle 111a using friction of the roll brush 151b and / or tail comb 152b. After the physical cleaning operation is completed, if necessary, a chemical cleaning operation is performed by discharging a cleaning solution from the cleaning needle 141 as shown in FIG. 5, in which the tip of the spinning needle 111a, which has undergone the reciprocating piercing and physical cleaning operations, is washed with a cleaning solvent.

[0089] In the electrospinning process of the present invention, the discharge rate of the spinning solution per spinning needle is preferably 0.5 μL / min to 500 μL / min, and more preferably 1 μL / min to 100 μL / min, for the production of nanofibers. A high voltage is applied to the spinning needle 111a via the piercing support 121b and the piercing needle 121a by the high-voltage power supply 407, and the voltage strength is preferably 0.01 kV / cm to 10 kV / cm, and more preferably 0.5 kV / cm to 6 kV / cm, based on the distance (cm) between the tip of the spinning needle and the collector.

[0090] The collector 403 is composed of a conveyor, multiple rollers, or multiple wires that can rotate together with the substrate, reducing friction as the substrate moves. The collector 403 is made of a conductive material such as a metal material, and may be grounded or may be powered by a DC power source (1 kV to 20 kV) with a polarity opposite to that of the charged solution. The substrate transport speed is preferably 10 cm per minute to 50 cm per minute. In addition, hot air is injected to volatilize the solvent contained in the charged solution discharged from the spinning needle 111a during standby, and is set at a speed of 0.1 m / sec to 10 m / sec and a temperature range of 20°C to 150°C. The hot air temperature is more preferably 30°C to 80°C.

[0091] According to the electrospinning apparatus of the present invention, clogging due to solidification of the solution at the tip of the spinning needle caused by evaporation of the solvent can be prevented, and the tip of the spinning needle can be cleaned cleanly, so that there is no need to replace the nozzle for the subsequent process, thereby ensuring the continuity of the spinning process. In particular, the nozzle block of the present invention can be applied to an upward-type roll-to-roll electrospinning apparatus.

[0092] Although the electrospinning apparatus and the nozzle block applied thereto according to the present invention have been described in detail and shown in the drawings, these are merely examples and do not limit the concept of the present invention. Various changes and modifications may be made within the scope of the technical concept of the present invention.

[0093] Furthermore, since various substitutions, modifications and changes can be made by a person having ordinary knowledge in the technical field to which the present invention belongs without departing from the technical spirit of the present invention, the present invention is not limited to the above-described embodiments and the attached drawings.

Claims

1. A nozzle block applied to electrospinning, a spinning nozzle including a plurality of hollow spinning needles for discharging the spinning solution to the outside; a hollow piercing needle having an outer diameter smaller than the inner diameter of the spinning needle and arranged coaxially with the spinning needle; At least one rotating brush is disposed on the left and / or right side of each of the spinning needles, and rotates to clean the exterior of the spinning needle; a hollow guide needle, which is disposed below and spaced a predetermined distance from the spinning needle in the coaxial direction to guide the piercing needle so that it can accurately enter the interior of the spinning needle without error, and which has an inner diameter and an outer diameter equal to or larger than those of the spinning needle; a reciprocating drive means for reciprocating the piercing needle and the spinning needle relative to each other, A nozzle block equipped with a cleaning means, characterized in that the piercing needle and the spinning needle are moved back and forth relative to each other to pierce clogged parts at the tip of the spinning needle, and the at least one rotating brush is used to clean agglomerates deposited on the outside of the tip of the spinning needle.

2. 2. The nozzle block with cleaning means according to claim 1, wherein the distance between the spinning needle and the guide needle is 1 mm to 10 mm.

3. 2. A nozzle block equipped with a cleaning means as described in claim 1, further comprising a cleaning needle having an inner diameter larger than the outer diameter of the spinning needle, arranged coaxially surrounding the spinning needle, and configured to clean the tip of the spinning needle by ejecting a cleaning liquid.

4. A nozzle block applied to electrospinning, comprising: a spinning nozzle including a plurality of hollow spinning needles for discharging the spinning solution to the outside; a piercing means having a diameter smaller than that of the spinning needle and arranged coaxially with the spinning needle; At least one rotating brush is disposed on the left and / or right side of each of the spinning needles, and rotates to clean the exterior of the spinning needle; a reciprocating drive means for reciprocating the piercing means and the spinning needle relative to each other, A nozzle block equipped with a cleaning means, characterized in that the piercing means and the spinning needle are moved back and forth relative to each other to pierce the clogged tip of the spinning needle, and the at least one rotating brush is used to clean the agglomerates deposited on the outside of the tip of the spinning needle, The piercing means may be guided to accurately enter the interior of the spinning needle without error, and the piercing means may further include a hollow guide needle that is disposed below the spinning needle at a predetermined distance in the coaxial direction, and has an inner diameter and an outer diameter that are equal to or larger than those of the spinning needle; A nozzle block equipped with a cleaning means, further comprising a rotary driving means for linearly reciprocating the rotary brush relative to the spinning needle and rotating the rotary brush around a central axis.

5. 5. The nozzle block equipped with cleaning means according to claim 4, wherein the rotating brush is a brush having a roll brush attached to a round bar or a brush having a tail comb attached to a round bar.

6. 2. The nozzle block equipped with a cleaning means according to claim 1, wherein the piercing needle is arranged coaxially inside the guide needle, and the tip of the piercing needle is positioned flush with the tip of the guide needle or positioned within 5 mm below.

7. 7. The nozzle block with cleaning means according to claim 6, wherein the outer diameter of the piercing needle is 0.005 mm to 1 mm smaller than the inner diameter of the spinning needle.

8. 2. The nozzle block with cleaning means according to claim 1, wherein said reciprocating drive means is a pneumatic drive tool for reciprocating said piercing needle up and down relative to said spinning needle.

9. 4. The nozzle block equipped with cleaning means according to claim 3, wherein the cleaning needle has an inner diameter that is 0.1 mm to 5 mm larger than the outer diameter of the spinning needle.

10. 4. The nozzle block equipped with cleaning means according to claim 3, wherein the cleaning needle is arranged coaxially below the tip of the spinning needle by 0.1 mm to 5 mm.

11. 2. The nozzle block with cleaning means according to claim 1, wherein the at least one rotating brush is a pair of rotating brushes disposed on the left and right sides of the tip of the spinning needle at a predetermined distance from each other.

12. 2. The nozzle block equipped with the cleaning means according to claim 1, wherein the piercing needle is raised so that the protruding length of the piercing needle is 0.5 mm to 20 mm.

13. a first nozzle support for supporting and fixing at least two of the spinning needles in a row; a second nozzle support for supporting and fixing at least two or more guide needles arranged in a row so as to correspond to the spinning needles fixed to the first nozzle support; 2. The nozzle block with cleaning means according to claim 1, further comprising: a third nozzle support member for supporting and fixing at least two of the piercing needles arranged in a row so as to be guided inside the guide needle fixed to the second nozzle support member.

14. The method further includes a cleaning needle having an inner diameter larger than the outer diameter of the spinning needle, arranged coaxially surrounding the spinning needle, and configured to discharge a cleaning solution to clean the tip of the spinning needle; 14. The nozzle block equipped with a cleaning means according to claim 13, further comprising a fourth nozzle support for supporting and fixing at least two or more cleaning needles arranged in a row so as to coaxially surround at least a portion of the tip of the spinning needle.

15. an unwinding unit that unwinds a roll around which a substrate for spinning a spinning solution to laminate nanofibers is wound; a winding unit that winds up the substrate on which the nanofibers are laminated; a nozzle block according to claim 1 or 3; a collector for depositing nanofibers spun from the nozzle block while the substrate is being transported; a solution storage tank for storing the spinning solution; a solution transfer device for transferring the solution in the solution storage tank to the nozzle block; a high-voltage power supply device for applying a high voltage to the spinning solution discharged from the spinning needle of the nozzle block.

16. a robot driving unit for driving the nozzle block back and forth in the width direction of the substrate; The electrospinning apparatus of claim 15, further comprising a spinning distance adjusting unit for adjusting a distance between the collector and the tip of the spinning needle.

17. a hot air generator for volatilizing the solvent from a large amount of spun filaments spun from the spinning needles of the nozzle block to produce fine nanofibers; a humidity control device for controlling the solvent evaporation rate by adjusting the internal humidity; The electrospinning apparatus of claim 15, further comprising: a lamination device for adjusting the bonding state of the nanofibers formed on the substrate.

18. 16. The electrospinning apparatus of claim 15, further comprising a video camera for monitoring in real time a solidification state or clogging state of the spinning solution formed at the tip of the spinning needle or a droplet state of a Taylor cone formed at the tip of the spinning needle.

19. The electrospinning apparatus of claim 15, further comprising collection guide units disposed on the left and right sides of the nozzle block to deposit the spun nanofibers in a limited area of ​​the collector.

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