ELECTROSPINNING NOZZLE BLOCK HAVING GAS EJECTION MEANS AND ELECTROSPINNING DEVICE COMPRISING SAME

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage entry of International Application No. PCT/KR2023/015858, filed on Oct. 13, 2023, which, in turn, claims priority to KR Patent Application No. 10-2022-0135897, filed on Oct. 20, 2022, both of which are hereby incorporated herein by reference in their entireties for all purposes.

TECHNICAL FIELD

The present disclosure relates to an electrospinning device, and more specifically, to a nozzle block for electrospinning, which has an air ejection unit for forming an air flow layer that moves straight while surrounding a spinning filament ejected from a spinning nozzle at a distance from an outlet, and an electrospinning device including the nozzle block.

BACKGROUND ART

The electrospinning process is a process of manufacturing nanofibers in an environment where an electric field is formed by applying a DC high voltage of several thousand to tens of thousands of volts to a solution and connecting a ground or negative (−) voltage to a current collector.

A droplet of a charged spinning solution discharged from the spinning nozzle is formed in a conical shape at the nozzle tip, and a charged filament is formed as the conical protrusion extends in a longitudinal direction toward the current collector. At this time, the conical portion of the droplet is called a Taylor cone, and the charged filament extended in a longitudinal direction is called a jet.

The jet, which is created by being extended from the protrusion of the Taylor cone, goes through a whipping mode in which it rapidly fluctuates from any point above a critical high voltage to evaporate the solvent, thereby producing nanofibers with a very small diameter. At this time, as the concentration of the spinning solution increases, the size of the Taylor cone decreases, the length of the straight jet increases, and the number of occurrences of the whipping mode decreases.

When using a spinning solution with a high surface tension, it is difficult to convert from a conical Taylor cone to a jet-like charged filament because the surface tension of the droplet is greater than the electric force. If the charged droplets are not completely converted into charged filaments, some of the discharged solution is collected on the collecting plate as fine droplets rather than fibers, which makes a nanofiber web containing fine droplets, so it is difficult to manufacture a uniform web. For this reason, in the case of an aqueous solution with a high surface tension or a spinning solution with a high solution viscosity, spinning is performed by increasing the high voltage intensity or reducing the discharge amount.

However, if the intensity of the high voltage applied to the spinning solution is increased, the Taylor cone at the tip of the nozzle becomes unstable, and the charged filament jet also cannot maintain directionality, making it difficult to uniformly collect nanofibers in the desired area of the collection unit. In addition, if the discharge amount of the spinning solution is reduced, there is a problem that the productivity of nanofibers decreases.

Therefore, in the electrospinning process, it is difficult to fundamentally solve the problem of a large number of fine droplets being included in the nanofiber web laminated on the collection plate.

In order to overcome the problems caused by the high surface tension of the spinning solution, in the prior art, various methods have been proposed to add auxiliary pressure means such as air or gas to the outside of the spinning filament.

Patent Literature 1 (Korean Patent Registration No. 10-1601169) discloses an electrospinning device, which includes a spinning nozzle having a plurality of needles for spinning nanofibers, and a constant temperature and humidity unit for directly spraying constant temperature and humidity air onto the nanofibers spun between the spinning nozzles arranged in a plurality of rows. However, Patent Literature 1 is intended to prevent temperature and humidity from varying depending on location by spraying constant temperature and humidity air onto a nanofiber web accumulated on a collector, and is not able to prevent fine droplets generated from the discharged spinning solution.

Patent Literature 2 (Korean Patent Registration No. 10-1440448) discloses an electrospinning nozzle module for spraying and coating a drug on a target object, which includes a housing having an exhaust hole formed at one end thereof to spray nitrogen gas supplied from the outside to the outside through the exhaust hole; and a nozzle portion having one end inserted into the exhaust hole to spray a drug to the outside and the other end supplied with electricity, wherein the exhaust hole is arranged at the periphery of one end of the nozzle, and when the drug is sprayed through one end of the nozzle portion, nitrogen gas is also sprayed through the periphery of one end of the nozzle. The configuration of Patent Literature 2 in which the exhaust holes of the nitrogen gas are arranged at eh periphery of one end of the nozzle is to prevent the drug from being exposed to the general air and becoming contaminated when spraying and coating the drug.

Patent Literature 3 (Korean Patent Registration No. 10-1478184) discloses an electrospinning nozzle pack, which includes a body having a solution receiving space for receiving a supplied solution; a plurality of solution injection nozzles installed in the body along a longitudinal direction so as to be in communication with the solution receiving space; and a gas injection nozzle arranged to surround the solution injection nozzles so as to penetrate the center thereof. Patent Literature 3 also has a problem in that the inlet of the injection nozzle is blocked due to solidification of the solution discharged from the solution injection nozzle because the gas injection nozzle is arranged to surround the solution injection nozzle.

DISCLOSURE

Technical Problem

In the above conventional technologies, particularly, in Patent Literatures 2 and 3, a solution injection nozzle, which is a solution outlet, is disposed at the center of the nozzle, and a cap having a center hole larger than the outer diameter of the solution injection nozzle is disposed at the periphery of the nozzle to inject air or gas into the space formed between the nozzle and the cap, thereby atomizing the spinning solution.

However, in these conventional technologies, air or gas is directly discharged to the periphery that comes into contact with the solution injection nozzle, so there is a problem in that solidification occurs at the tip of the solution injection nozzle and directly affects the airflow of the spinning solution.

Therefore, the present disclosure is directed to suppressing the generation of fine droplets by rapidly converting the jet droplets into spinning filaments by vertically ejecting an air stream at the periphery the spinning filaments flying in the air layer to increase their radial velocity.

In addition, the present disclosure has a second technical challenge of vertically ejecting an air stream to the periphery of the spinning filament flying in an air layer without affecting the tip of the spinning nozzle.

These and other objects and advantages of the present disclosure may be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of the present disclosure. Also, it will be easily understood that the objects and advantages of the present disclosure may be realized by the means shown in the appended claims and combinations thereof.

Technical Solution

An electrospinning nozzle block according to the first aspect of the present disclosure comprises: an inner space for accommodating a spinning solution transferred and injected from a solution storage tank, a nozzle body including a plurality of solution distribution ports, an electrospinning nozzle including an airflow ejection unit, a nozzle adapter for detachably coupling the electrospinning nozzle to the nozzle body, and a high voltage applying unit for applying high voltage electricity from a high voltage generating device to the spinning solution accommodated in the inner space of the nozzle body, wherein the electrospinning nozzle includes: an inner nozzle body into which a spinning solution serving as a first fluid is injected; an inner needle unit connected to the inner nozzle body and having a hollow tube-shaped inner needle serving as an outlet of the first fluid; an outer nozzle body into which air serving as a second fluid is injected; and an air ejection unit coupled to a tip of the outer nozzle body and configured to generate a flow of the air serving as the second fluid moving straight while surrounding a spinning filament ejected from the inner needle at a distance from the outlet, wherein the air ejection unit includes a center hole penetrating the inner needle and a plurality of gas ejection ports radially arranged to surround the center hole to be spaced apart from each other by a predetermined distance, wherein the high voltage applying unit includes: a high voltage applying needle with high conductivity corresponding to the electrospinning nozzle in one-to-one relationship; and a high voltage body configured to fix and arrange the high voltage applying needle in a width direction, wherein the nozzle body has a plurality of holes for allowing the high voltage applying needle to path, the plurality of holes being formed opposite to a side where the electrospinning nozzle is coupled.

According to the second aspect of the present disclosure, in the electrospinning nozzle block of the first aspect, the gas ejection port may include a plurality of air holes for discharging the air serving the second fluid to the outside so that at least two of the plurality of air holes are arranged at regular intervals in a plurality of circumferential regions, which are formed by at least one circular line centered on the center hole on a periphery thereof.

According to the third aspect of the present disclosure, in the electrospinning nozzle block of the second aspect, the gas ejection port may include a first gas ejection port having at least two air holes arranged in a first circumferential region, which is a first circular line surrounding the center hole and spaced apart from the center hole by a radius r₁; and a second gas ejection port having at least two air holes arranged in a second circumferential region, which is a second circular line surrounding the center hole and spaced apart from the center hole by a radius r₂, and the radius r₂ of the second circumferential region may be larger than the radius r₁ of the first circumferential region.

According to the fourth aspect of the present disclosure, in the electrospinning nozzle block of the third aspect, a plurality of n^th circumferential regions (where n is a natural number greater than or equal to 3) may be further arranged outside the second circumferential region to surround the second circumferential region, and at least two air holes may be arranged in the n^th circumferential region.

According to the fifth aspect of the present disclosure, in the electrospinning nozzle block of the fourth aspect, six air holes may be arranged at a 60° angle to each other in the first circumferential region, the second circumferential region, and the n^th circumferential region.

According to the sixth aspect of the present disclosure, in the electrospinning nozzle block of the fifth aspect, the air ejection unit may include a side fastening unit coupled with the extended tip of the outer nozzle body and a cover unit in which the center hole and a plurality of gas discharge ports arranged to surround the center hole are formed, and the air ejection unit may be an air cap having a retention space of the air serving as the second fluid, which is formed therein by the side fastening unit and the cover unit.

According to the seventh aspect of the present disclosure, the electrospinning nozzle block of the sixth aspect may further comprise a hollow tube-shaped guide needle configured to guide the high voltage applying needle to enter the hole stably, and the guide needle may be disposed between the high voltage body and the nozzle body, and an inner diameter of the guide needle is larger than a diameter of the high voltage applying needle.

According to the eighth aspect of the present disclosure, in the electrospinning nozzle block of the sixth aspect, the high voltage applying needle may be disposed coaxially inside the inner needle of the electrospinning nozzle or coaxially inside a solution storage space of the inner nozzle body.

According to the ninth aspect of the present disclosure, the electrospinning nozzle block of the sixth aspect may further comprise a linear reciprocating mechanism configured to move the high voltage applying unit up and down in a longitudinal direction of the nozzle.

According to the tenth aspect of the present disclosure, in the electrospinning nozzle block of the sixth aspect, an arrangement interval of the electrospinning nozzles attached to the nozzle body may be 20 mm to 70 mm.

According to the 11^th aspect of the present disclosure, in the electrospinning nozzle block of the sixth aspect, the high voltage body may be configured as a circular or rectangular rod made of a metal material that is electrically conductive inside an insulating cylindrical or rectangular pipe, and the high voltage applying needle is coupled to the metal rod in one-to-one relationship.

According to the 12^th aspect of the present disclosure, in the electrospinning nozzle block of the sixth aspect, the high voltage applying needle may be a metallic hollow needle or a metallic wire.

An electrospinning nozzle block according to the 13^th aspect of the present disclosure comprises: an inner space for accommodating a spinning solution transferred and injected from a solution storage tank, a nozzle body including a plurality of solution distribution ports, an electrospinning nozzle including an airflow ejection unit, a nozzle adapter for detachably coupling the electrospinning nozzle to the nozzle body, and a high voltage applying unit for applying high voltage electricity from a high voltage generating device to the spinning solution accommodated in the inner space of the nozzle body, wherein the electrospinning nozzle includes: an inner nozzle body into which a first fluid is injected; an inner needle unit connected to the inner nozzle body and having a hollow tube-shaped inner needle serving as an outlet for the first fluid; an outer nozzle body into which a second fluid is injected; an outer needle unit connected to the outer nozzle body and having a hollow tube-shaped outer needle serving as an outlet for the second fluid and arranged to coaxially surround the inner needle; an outer needle positioning unit configured to adjust a central axis position of the outer needle; a gas inlet configured to inject air that is a gas; and an air ejection unit coupled to a tip of the outer needle positioning unit and configured to generate a flow of the air moving straight while surrounding a spinning filament ejected from a double needle, which is formed by the outer needle coaxially surrounding the inner needle, at a distance from the outlet, wherein the air ejection unit includes a center hole penetrating the double needle and a plurality of gas ejection ports radially arranged to surround the center hole to be spaced apart from each other by a predetermined distance, wherein the high voltage applying unit includes: a high voltage applying needle with high conductivity corresponding to the electrospinning nozzle in one-to-one relationship; and a high voltage body configured to fix and arrange the high voltage applying needle in a width direction, wherein the nozzle body has a plurality of holes for allowing the high voltage applying needle to path, the plurality of holes being formed opposite to a side where the electrospinning nozzle is coupled.

According to the 14^th aspect of the present disclosure, in the electrospinning nozzle block of the 13^th aspect, the outer needle positioning unit may include a positioning unit body having a cylindrical shape and arranged between the outer needle unit and the air ejection unit to form a gas flow path, and a plurality of screw pins installed on a part of the positioning unit body to adjust a central axis of the outer needle.

According to the 15^th aspect of the present disclosure, in the electrospinning nozzle block of the 14^th aspect, the gas inlet may be formed at one end of the positioning unit body, and the air injected through the gas inlet may be discharged to the air ejection unit.

According to the 16^th aspect of the present disclosure, in the electrospinning nozzle block of the 15^th aspect, the plurality of screw pins may be arranged to surround a periphery of the outer needle to be spaced apart at a predetermined angle to each other on a periphery of a part of the positioning unit body.

According to the 17^th aspect of the present disclosure, in the electrospinning nozzle block of the 16^th aspect, an inner diameter of the outer needle may be larger than an outer diameter of the inner needle by 5 μm to 1,000 μm, and a distance between the central axes of the inner needle and the outer needle may be less than 0.1 mm.

According to the 18^th aspect of the present disclosure, in the electrospinning nozzle block of the 16^th aspect, the gas ejection port may include a plurality of air holes for discharging the air serving the second fluid to the outside so that at least two of the plurality of air holes are arranged at regular intervals in a plurality of circumferential regions, which are formed by at least one circular line centered on the center hole on a periphery thereof.

According to the 19^th aspect of the present disclosure, in the electrospinning nozzle block of the 16^th aspect, the gas ejection port may include a first gas ejection port having at least two air holes arranged in a first circumferential region, which is a first circular line surrounding the center hole and spaced apart from the center hole by a radius r₁; and a second gas ejection port having at least two air holes arranged in a second circumferential region, which is a second circular line surrounding the center hole and spaced apart from the center hole by a radius r₂, and the radius r₂ of the second circumferential region may be larger than the radius r₁ of the first circumferential region.

According to the 20^th aspect of the present disclosure, in the electrospinning nozzle block of the 19^th aspect, a plurality of nth circumferential regions (where n is a natural number greater than or equal to 3) may be further arranged outside the second circumferential region to surround the second circumferential region, and at least two air holes may be arranged in the n^th circumferential region.

According to the 21^st aspect of the present disclosure, in the electrospinning nozzle block of the 20^th aspect, six air holes may be arranged at a 60° angle to each other in the first circumferential region, the second circumferential region, and the n^th circumferential region.

According to the 22^nd aspect of the present disclosure, in the electrospinning nozzle block of the 21^st aspect, the air ejection unit may include a side fastening unit coupled with the extended tip of the outer needle positioning unit and a cover unit in which the center hole and a plurality of gas discharge ports arranged to surround the center hole are formed, and the air ejection unit may be an air cap having a retention space of the air, which is formed therein by the side fastening unit and the cover unit.

According to the 23^rd aspect of the present disclosure, the electrospinning nozzle block of the 22^nd aspect may further comprise a hollow tube-shaped guide needle configured to guide the high voltage applying needle to enter the hole stably, and the guide needle may be disposed between the high voltage body and the nozzle body, and an inner diameter of the guide needle is larger than a diameter of the high voltage applying needle.

According to the 24^th aspect of the present disclosure, in the electrospinning nozzle block of the 22^nd aspect, the high voltage applying needle may be disposed coaxially inside the inner needle of the electrospinning nozzle or coaxially inside a solution storage space of the inner nozzle body.

An electrospinning nozzle block according the 25^th aspect of the present disclosure comprises: an inner space for accommodating a spinning solution transferred and injected from a solution storage tank, a nozzle body including a plurality of solution distribution ports, an electrospinning nozzle including an airflow ejection unit, a nozzle adapter for detachably coupling the electrospinning nozzle to the nozzle body, and a high voltage applying unit for applying high voltage electricity from a high voltage generating device to the spinning solution accommodated in the inner space of the nozzle body, wherein the electrospinning nozzle includes: an inner nozzle body having a first fluid inlet into which a first fluid is injected; an inner needle unit connected to the inner nozzle body and having a hollow tube-shaped inner needle serving as an outlet of the first fluid; an outer nozzle body having a second fluid inlet into which air as a second fluid is injected; a pneumatic control unit body including a needle shaft for controlling and blocking a flow of the first fluid transferred to the inner needle unit and a needle shaft sealing portion for preventing the first fluid from flowing backward and leaking to the upper portion of the needle shaft; and an air ejection unit connected to a tip of the outer nozzle body to generate a flow of air serving as the second fluid moving straight while surrounding a spinning filament ejected from the inner needle at a distance from the outlet, wherein the air ejection unit includes a center hole penetrating the inner needle and a plurality of gas ejection ports radially arranged to surround the center hole to be spaced apart from each other by a predetermined distance, wherein the high voltage applying unit includes: a high voltage applying needle with high conductivity corresponding to the electrospinning nozzle in one-to-one relationship; and a high voltage body configured to fix and arrange the high voltage applying needle in a width direction, wherein the nozzle body has a plurality of holes for allowing the high voltage applying needle to path, the plurality of holes being formed opposite to a side where the electrospinning nozzle is coupled.

According to the 26^th aspect of the present disclosure, in the electrospinning nozzle block of the 25^th aspect, the pneumatic control unit body may further include an air inlet for injecting air into the needle shaft, and the needle shaft may include a spring wound around the needle shaft and having an elastic restoring force; a taper blocking portion formed at a tip of the needle shaft to block a fluid passage toward the inner needle unit in order to block the flow of the first fluid, and a shaft needle connected to the taper blocking portion and having a pointed end penetrating the inner needle and protruding through a front end of the inner needle.

According to the 27^th aspect of the present disclosure, in the electrospinning nozzle block of the 26^th aspect, the gas ejection port may include a plurality of air holes for discharging the air serving the second fluid to the outside so that at least two of the plurality of air holes are arranged at regular intervals in a plurality of circumferential regions, which are formed by at least one circular line centered on the center hole on a periphery thereof.

According to the 28^th aspect of the present disclosure, in the electrospinning nozzle block of the 27^th aspect, the gas ejection port may include a first gas ejection port having at least two air holes arranged in a first circumferential region, which is a first circular line surrounding the center hole and spaced apart from the center hole by a radius r₁; and a second gas ejection port having at least two air holes arranged in a second circumferential region, which is a second circular line surrounding the center hole and spaced apart from the center hole by a radius r₂, and the radius r₂ of the second circumferential region may be larger than the radius r₁ of the first circumferential region.

According to the 29^th aspect of the present disclosure, in the electrospinning nozzle block of the 28^th aspect, a plurality of n^th circumferential regions (where n is a natural number greater than or equal to 3) may be further arranged outside the second circumferential region to surround the second circumferential region, and at least two air holes may be arranged in the n^th circumferential region.

According to the 30^th aspect of the present disclosure, in the electrospinning nozzle block of the 29^th aspect, six air holes may be arranged at a 60° angle to each other in the first circumferential region, the second circumferential region, and the n^th circumferential region.

According to the 31^st aspect of the present disclosure, in the electrospinning nozzle block of the 30^th aspect, the air ejection unit may include a side fastening unit coupled with the extended tip of the outer nozzle body and a cover unit in which the center hole and a plurality of gas discharge ports arranged to surround the center hole are formed, and the air ejection unit may be an air cap having a retention space of the air serving as the second fluid, which is formed therein by the side fastening unit and the cover unit.

According to the 32^nd aspect of the present disclosure, the electrospinning nozzle block of the 31^st aspect may further comprise a hollow tube-shaped guide needle configured to guide the high voltage applying needle to enter the hole stably, and the guide needle may be disposed between the high voltage body and the nozzle body, and an inner diameter of the guide needle is larger than a diameter of the high voltage applying needle.

According to the 33^rd aspect of the present disclosure, in the electrospinning nozzle block of the 31^st aspect, the high voltage applying needle may be disposed coaxially inside the inner needle of the electrospinning nozzle or coaxially inside a solution storage space of the inner nozzle body.

An electrospinning device according to the 34^th aspect of the present disclosure comprises: an unwinder unit as serving an unwinder for unwinding a roll on which a substrate is wound to radiate a spinning solution and laminate nanofibers; a winder unit serving as a winder for winding the substrate on which nanofibers are laminated; at least one nozzle block array formed by connecting at least one electrospinning nozzle block according to any one of the first to 33^rd aspects in a width direction of the substrate; a collector configured to laminate nanofibers radiated from the at least one nozzle block array while transporting the substrate; a solution storage tank configured to store the spinning solution; a solution transport mechanism configured to transport the spinning solution from the solution storage tank to a spinning nozzle of the modular electrospinning nozzle block; and a high voltage power supply configured to apply a DC high voltage to the spinning solution.

According to the 35^th aspect of the present disclosure, the electrospinning device of the 34^th aspect may further comprise a robot driving unit configured to reciprocate the nozzle block array in the width direction of the substrate; a radiation distance adjusting unit configured to move the nozzle block array up and down to adjust a distance between the collector and a tip of a spinning needle; and a collection guide unit configured to laminate nanofibers, which are arranged and spun at left and right sides of the nozzle block array in a direction in which the substrate is transported, into a limited area of the collector.

According to the 36^th aspect of the present disclosure, the electrospinning device of the 35^th aspect may further comprise a hot air generating device configured to evaporate a solvent from a large amount of spinning filaments spun from the spinning needle of the nozzle block array to create fine nanofibers; a humidity control device configured to control a solvent evaporation rate by controlling an internal humidity of the electrospinning device; and a lamination device configured to control a coupling state of the nanofibers formed on the substrate.

Advantageous Effects

According to the present disclosure, the following effects may be obtained from an electrospinning nozzle block and an electrospinning device including an electrospinning nozzle having a porous gas ejection port spaced at a predetermined distance from a center hole through which a spinning needle passes.

First, nanofibers may be manufactured more efficiently without generating fine droplets from the discharged droplets, and a uniform nanofiber web may be manufactured.

Second, the production speed of nanofibers may be enhanced by increasing the solvent volatilization rate and increasing the discharge amount of the solution.

Third, by applying a straight air layer flow to the periphery of the spinning filament flying in a whipping mode in the air layer section, the solution outlet of the nozzle is not directly affected, so that the phenomenon of the solution solidifying at the nozzle tip may be prevented.

DESCRIPTION OF DRAWINGS

The accompanying drawings illustrate a preferred embodiment of the present disclosure and together with the foregoing disclosure, serve to provide further understanding of the technical features of the present disclosure, and thus, the present disclosure is not construed as being limited to the drawing.

FIG. 1 is a cross-sectional view showing an electrospinning nozzle according to the first embodiment of the present disclosure.

FIG. 2 is a cross-sectional view showing an air ejection unit of the electrospinning nozzle of FIG. 1 taken along line A-A.

FIG. 3 is a longitudinal cross-sectional view showing the air ejection unit of FIG. 2 taken along line B-B.

FIG. 4 is a cross-sectional view showing an electrospinning nozzle according to the second embodiment of the present disclosure.

FIG. 5 is a cross-sectional view showing an electrospinning nozzle according to the third embodiment of the present disclosure.

FIG. 6 is a schematic perspective view showing the configuration of an electrospinning nozzle block to which the electrospinning nozzle according to the present disclosure is applied.

FIG. 7 is a perspective view showing a top-down roll-to-roll electrospinning device in which a plurality of electrospinning nozzle blocks of FIG. 6 are arranged in series.

BEST MODE

The present disclosure may have various modifications and embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments, but should be understood to include all modifications, equivalents, or substitutes included in the idea and technical scope of the present disclosure.

When it is recited that a component “is connected” or “accesses” to another component, it should be understood that the component may be directly connected or access to another component, but there may also be other components present between them.

Meanwhile, when it is recited that a component “is directly connected” or “directly accesses” to another component, it should be understood that there are no other components between them.

The terminology used herein is only used to describe particular embodiments and is not intended to limit the present disclosure. The singular form includes pluralities unless the context clearly indicates otherwise. In this application, it should be understood that the terms “comprises” or “has” and the like are intended to specify the presence of a feature, number, process, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, processes, operations, components, parts or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. Terms defined in commonly used dictionaries, such as those defined in the present disclosure, should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense, unless expressly defined in this application.

Terms or words used in this specification and claims should not be interpreted as limited to their common or dictionary meanings, and should be interpreted as meanings and concepts that conform to the technical idea of the present disclosure based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best way. In addition, if there is no other definition for the technical and scientific terms used, they have the meanings commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs, and the description of well-known functions and configurations that may unnecessarily obscure the gist of the present disclosure in the following description and the attached drawings are omitted. The drawings introduced below are provided as examples so that those skilled in the art can sufficiently convey the idea of the present disclosure. Therefore, the present disclosure is not limited to the drawings presented below and may be embodied in other forms. In addition, the same reference signs represent the same components throughout the specification. It should be noted that the same components in the drawings are represented by the same symbols wherever possible.

A preferred embodiment of the present disclosure will be described in detail below with reference to the attached drawings. The attached drawings are not drawn to scale, and like reference signs in each drawing refer to like components.

Electrospinning Nozzle

First Embodiment

FIG. 1 is a cross-sectional view showing an electrospinning nozzle provided with an air ejection unit according to the first embodiment of the present disclosure.

Referring to FIG. 1, the electrospinning nozzle 100 according to this embodiment includes an inner nozzle body 101 into which a spinning solution serving as a first fluid is injected, an outer nozzle body 102 into which air serving as a second fluid is injected, an inner needle unit 103 having a hollow needle 103a serving as an outlet of the first fluid, an air ejection unit 104 coupled to a tip of the outer nozzle body 102 to generate a flow of air serving as the second fluid that moves straight line while surrounding a charged filament at a distance from the outlet by the spinning solution ejected from the hollow needle 103a, and a high voltage applying unit 106 connected to the inner nozzle body 101.

The inner nozzle body 101 includes a first fluid inlet 101a into which a spinning solution serving as the first fluid is injected, a solution storage space 101b in which the spinning solution flows and remains, and a tapered outlet 101c that delivers the spinning solution to the inner needle 103a.

The inner needle unit 103 is detachably coupled to the inner nozzle body 101 through the inner needle fastening cap 105.

The outer surface of the inner nozzle body 101 may have a thread for fixing with a specific external fixing member (not shown).

A syringe or a male fitting having an outlet of a Luer lock structure configured in the shape of a double screw may be coupled to the first fluid inlet 101a of the inner nozzle body 101, or a fitting for fastening a tubing may be connected thereto. In addition, the outlet 101c of the inner nozzle body 101 is configured in a Luer taper shape so as to be in close contact with and coupled to the socket portion of the inner needle unit 103. In addition, the solution storage space 101b of the inner nozzle body 101 may be used as a path through which the spinning solution is transported, or as a storage space for temporarily retaining the solution.

The connection standard of the Luer taper of the outlet 101c of the inner nozzle body 101 follows ISO 594 standards {ISO 594-1:1986“Conical fittings with a 6% (Luer) taper for syringes, needles and certain other medical equipment”. [1] (https://www.iso.org/standard/4693.html)}.

It is preferable that the material of the inner nozzle body 101 be a conductive metal such as stainless steel (SUS), aluminum, nickel or chrome-plated copper, nickel or chrome-plated copper, etc. Meanwhile, if the spinning solution serving as the first fluid is a biopolymer solution containing cells, the material of the inner nozzle body 101 may be a fluorine-based polymer such as Teflon, PEEK (polyetheretherketone), or a non-metallic material such as carbide or quartz.

A high voltage applying unit 106 is connected and installed to the inner nozzle body 101 to apply a direct current high voltage of several tens to tens of thousands of volts. Therefore, when a high voltage is applied to the inner nozzle body 101, the spinning solution discharged from the tip of the inner needle 103a is charged by the high voltage.

The inner needle unit 103, which is detachably coupled to the inner nozzle body 101 through the inner needle fastening cap 105, has a hollow tube-shaped inner needle 103a for discharging the spinning solution to the outside. The inner needle 103a is coupled to the inner needle unit 103 with a hub or sleeve interposed therebetween.

The sleeve may be a hollow tube or may be configured as a hollow screw having an external thread. When the sleeve is made of a polymer having flexibility and elasticity, it becomes easier to replace the hollow needle 103a from the inner needle unit 103. For example, the hollow tube-shaped sleeve is preferably made of a flexible material having chemical resistance, such as fluorinated ethylene propylene (FEP), perfluoroalkoxy alkane (PFA), or polytetrafluoroethylene (PTFE).

In addition, in order to provide conductivity to the inner needle 103a through the inner nozzle body 101, the sleeve may be made of a conductive polymer material containing carbon or a metal component. It is preferable that the inner diameter of the hollow tube-shaped sleeve is almost the same as the outer diameter of the inner needle 103a or smaller than the outer diameter of the inner needle 103a in order to have excellent adhesion to the inner needle 103a. That is, the hollow tube-shaped sleeve preferably has an inner diameter of 0.05 to 4 mm and an outer diameter of 1 to 5 mm. In addition, the sleeve may be made of copper, or a non-metal containing copper. More preferably, the material of the sleeve may be a non-ferrous metal type or an aluminum type containing copper, nickel-plated copper, or copper, or a SUS metal type, a moldable polymer type such as PEEK, etc.

It is preferable that the inner needle 103 a has an inner diameter of 0.005 mm to 2 mm, an outer diameter of 0.02 mm to 3 mm, and a length of 2 mm to 200 mm. The material of the inner needle 103a is preferably stainless steel (SUS), silica, quartz, superhard, fluorine, or PEEK-coated SUS.

The tip shape of the inner needle 103a may have a blunt end or a sharp tip shape. At this time, the corner angle of the blunt end may be a 90 degree tip, a chamfered tip with rounded corners, or a tapered tip with a tapered end.

When the inner needle unit 103 is coupled to the inner nozzle body 101, an inner needle fastening cap 105 is used. The inner needle fastening cap 105 is configured with a semicircular groove structure into which the hub of the inner needle unit 103 is mounted, or a Luer lock structure.

If the inner needle fastening cap 105 is configured with a semicircular groove structure, after the inner needle unit 103 is placed into the groove of the inner needle fastening cap 105 and mounted, if the cap 105 is turned, the socket portion of the hub of the inner needle unit 103 is pushed up to the top of the taper and coupled in contact thereto. Meanwhile, if the inner needle fastening cap 105 has a Luer lock structure having two threads therein, when the hub of the inner needle unit 103 is turned, it is pushed up to the top of the taper and coupled.

The outer nozzle body 102 is coupled to the inner nozzle body 101 while surrounding the inner needle unit 103 and at least a portion of the inner nozzle body 101. The outer nozzle body 102 includes a second fluid inlet 102a for injecting air serving as the second fluid, and a mounting space for mounting the inner needle unit 103. The second fluid inlet 102a is configured by coupling a female fitting or a fitting for tubing connection to a side portion. It is preferable that the female fitting material is an insulating material so as not to be affected by an electric field even when a high voltage is applied.

The air ejection unit 104 is fastened and coupled to the lower tip of the outer nozzle body 102. That is, a fastening tubing 102b extending in the longitudinal direction of the nozzle is formed at the lower tip of the outer nozzle body 102. It is preferable that the fastening tubing 102b have an outer diameter smaller than the outer diameter of the main body of the outer nozzle body 102. In addition, a thread may be formed on the outer surface of the fastening tubing 102b for attachment to or detachment from the air ejection unit 104.

The air ejection unit 104 is a type of air cover or air cap that is fastened to the fastening tubing 102b of the outer nozzle body 102 and covers the mounting space of the outer nozzle body 102 to form a space for retaining air serving as the second fluid.

The air ejection unit 104 includes a side fastening unit 104b screw-connected to the fastening tubing 102b and a cover unit 104a for covering the mounting space to form an air retention space. In addition, the cover unit 104a has a center hole 114 formed to penetrate the inner needle 103a and a plurality of gas discharge ports 115 arranged to surround the center hole 114.

FIG. 2 is a cross-sectional view showing the air ejection unit 104 according to the first embodiment of the present disclosure taken along line A-A, and FIG. 3 is a longitudinal cross-sectional view showing the air ejection unit 104 of FIG. 2 taken along line B-B.

Referring to FIG. 2, the air ejection unit 104 is configured as a kind of air cap including a center hole 114 penetrating the inner needle 103a and several to several dozen gas ejection ports 115 arranged to surround the center hole 114 with at least two or more circular lines. The gas ejection port 115 is an air hole that discharges air serving as the second fluid injected from the second fluid inlet 102a to the outside. As a result, several air flow layers 116 extending in a straight line parallel to the inner needle 103a are formed around the inner needle 103a penetrating through the center hole 114.

Three to eight gas ejection ports 115 may be arranged in a plurality of circumferential regions, which are formed by at least one circular line centered on the center hole 114, at regular intervals or randomly. For example, referring to FIG. 2, in a first circumferential region 111, which is a first circular line surrounding the center hole 114 and spaced apart from the center hole 114 by a radius r₁, six first gas ejection ports 115a are arranged at a 60° angle with respect to each other. In addition, in a second circumferential region 112, which is a second circular line surrounding the center hole 114 and spaced apart from the center hole 114 by a radius r₂, six second gas ejection ports 115b are arranged at a 60° angle with respect to each other. At this time, the radius r₂ of the second circumferential region 112 is larger than the radius r₁ of the first circumferential region 111. That is, the radius r₁ is 2 to 10 mm, more preferably 3 to 5 mm, and the radius r₂ is 4 to 20 mm, more preferably 4 to 10 mm. In addition, the gas ejection port 115 may be configured as a circular or rectangular hole, but is preferably configured as a circular hole. At this time, when the gas ejection port 115 is configured as a circular hole, the diameter of the circular hole is preferably 0.1 mm to 2 mm. In addition, the gas ejection port 115 may be configured by press-fitting a hollow needle having an inner diameter of 0.1 mm to 1 mm into the cover unit 104a of the air ejection unit 104 instead of the circular hole.

In FIG. 2, a configuration is illustrated in which a total of 12 first and second gas ejection ports 115a, 115b are arranged to surround the center hole 114 with two circular lines. However, the air ejection unit 104 of the present disclosure is not necessarily limited to this arrangement or configuration.

In this embodiment, a plurality of n^th circumferential regions (wherein, n is a natural number greater than or equal to 3) surrounding the second circumferential region 112 may be further arranged outside the second circumferential region 112. In addition, more than 6 gas ejection ports or fewer than 6 gas ejection ports may be arranged in the first circumferential region 111, the second circumferential region 112, and the n^th circumferential region (wherein, n is a natural number greater than or equal to 3). In addition, a plurality of gas ejection ports 115 arranged in one circumferential region may be arranged to have a constant angle (for example, 60°) with respect to each other, or may be arranged randomly without any rule regarding the angle.

The diameter of the center hole 114a is almost the same size as or slightly larger than the outer diameter of the hollow needle 103a passing through the center hole 114. For example, the diameter of the center hole 114 is preferably 0.001 mm to 0.5 mm larger than the outer diameter of the hollow needle 103a. More preferably, the diameter of the center hole 114 is set to be 0.001 mm to 0.1 mm larger than the outer diameter of the hollow needle 103a so that there is no gap between the center hole 114 and the hollow needle 103a, thereby preventing air serving as the second fluid from leaking out through the gap. In addition, it is preferable that the inlet portion through which the inner needle 103a passes through the center hole 114 is chamfered to facilitate the passage of the inner needle 103a. It is preferable that the thickness (h1) of the cover unit 104a, which is the bottom surface of the air cap serving as the air ejection unit 104, is 0.1 mm to 5 mm. More preferably, the thickness (h1) of the cover unit 104a is 0.5 mm to 2 mm. At this time, if the thickness (h1) of the cover unit 104a exceeds 5 mm, it is difficult to process a hole with a small diameter.

In order to prevent air injected into the outer nozzle body 102 from leaking, an O-ring may be installed between the fastening tubing 102b of the outer nozzle body 102 and the side fastening unit 104b of the air ejection unit 104. At this time, the material of the O-ring (O-ring) may be fluorine, Viton, olefin of ethylene-propylene, or silicone.

In addition, the hollow needle 103a protrudes through the center hole 114 of the air cap 104, and the protrusion length at this time is preferably 1 to 10 mm.

Hereinafter, the operation of the electrospinning nozzle according to this embodiment is described in detail.

First, the spinning solution serving as the first fluid is injected through the first fluid inlet 101a, and the spinning solution is ejected through the tip of the inner needle 103a. At this time, the air serving as the second fluid is injected through the second fluid inlet 102a, the air is ejected through a plurality of gas ejection ports 115 provided in the air cap, which is the air ejection unit 104. The spinning solution ejected from the inner needle 103a passes through a conical Taylor cone to be generated as a filament jet of a certain length, and then goes through a whipping mode in which the filament jet rapidly whips at a specific position, and as the solvent volatilizes, it is deposited as nanofibers on the collection unit.

The filament jet flies within a certain region of the air layer, and the straight air flow ejected from the gas discharge port 115 pushes the filament jet toward the collection unit within a certain distance to form a straight air flow layer, thereby suppressing the filament jet from spreading out or dispersing excessively in the whipping mode. The straight air flow concentrates on the charged filament in the whipping mode region. As a result, the charged filament by the spinning solution is stably formed, and then concentrated and deposited within a desired deposition region of the collection unit.

Second Embodiment

FIG. 4 is a cross-sectional view showing an electrospinning nozzle according to the second embodiment of the present disclosure.

The electrospinning nozzle 300 according to the second embodiment of the present disclosure further includes an outer needle arranged to coaxially surround the inner needle and an outer needle positioning unit for controlling a central axis position of the outer needle, in contrast to the electrospinning nozzle 100 of the first embodiment. That is, the electrospinning nozzle 300 according to this embodiment is substantially the same as the electrospinning nozzle 100 of the first embodiment, except that it additionally includes an outer needle unit 304 and an outer needle positioning unit 306 in addition to the configuration of the electrospinning nozzle 100 of the first embodiment. Therefore, the configuration of the electrospinning nozzle 300 of this embodiment that is the same as the electrospinning nozzle 100 of the first embodiment will not be described again in detail.

Referring to FIG. 4, the electrospinning nozzle 300 according to this embodiment includes an inner nozzle body 301 into which a first fluid is injected, an outer nozzle body 302 into which a second fluid is injected, an inner needle unit 303 connected to the inner nozzle body 301 and having a hollow tube-shaped inner needle 303a serving as an outlet for the first fluid, an outer needle unit 304 connected to the outer nozzle body 302 and having a hollow tube-shaped outer needle 304c serving as an outlet for the second fluid, an outer needle positioning unit 306 for controlling a central axis position of the outer needle 304c, an air ejection unit 307 coupled to the outer needle positioning unit 306 to eject gas around a double needle including an outer needle 304c coaxially surrounding the inner needle 303a, and a high voltage applying unit 308 connected to the inner nozzle body 301.

The second fluid injected into the outer needle unit 304 is injected into the second fluid inlet 302a, and gas (e.g., air) is injected into the gas inlet 306d.

The outer needle unit 304 includes a holder 304a into which an outer needle 304c having a sleeve 304b is press-fitted and coupled. A hole or thread is formed in the holder 304a of the outer needle unit 304 so that the sleeve 304b is press-fitted therein. At this time, it is preferable that the diameter of the hole of the holder 304a is processed to be slightly smaller than the outer diameter of the sleeve 304b so that leakage does not occur after the sleeve 304b of the outer needle 304c is press-fitted.

In addition, it is desirable to have a slight groove (R-processing) at the entrance of the hole of the holder 304a to facilitate the insertion of the sleeve 304b. In addition, if the sleeve 304b is processed to have a thread, it is desirable that the sleeve 304b is processed to have a unified national fine (UNF) thread of M2 to M5, preferably M3, to prevent leakage through the thread.

The outer needle positioning unit 306 includes a cylindrical positioning unit body 306a that is arranged between the outer needle unit 304 and the air ejection unit 307 to form a gas flow path, and a plurality of screw pins 306b that are installed on a part of the positioning unit body 306a to adjust a central axis of the outer needle 304c.

A gas inlet 306d is coupled to one end of the positioning unit body 306a, and gas injected through the gas inlet 306d is discharged through the gas flow path to a plurality of gas discharge ports 307a formed in the air ejection unit 307.

In addition, a fastening tubing 306c is formed at the lower tip of the positioning unit body 306a to be coupled with the side fastening unit of the air ejection unit 307. That is, the fastening tubing 306c extending in the longitudinal direction of the nozzle is formed at the lower tip of the outer adjustment body 360a. It is preferable that the fastening tubing 306c has a smaller outer diameter than the outer diameter of the positioning unit body 306a. In addition, a thread may be formed on the outer surface of the fastening tubing 306c to enable attachment to or detachment from the air ejection unit 307.

The plurality of screw pins 306b are arranged to surround the periphery of the outer needle 304c to be spaced apart at a certain angle (for example, at 60 degree intervals) from each other on the periphery of a part of the positioning unit body 306a. At this time, the plurality of screw pins 306b may be arranged in a row or in an upper and lower zigzag manner while surrounding the periphery of the outer needle 304c.

At least one screw pin 306b, preferably six screw pins 306b, are at 60 degree intervals to adjust the central axis of the outer needle 304c. At this time, the central position of the outer needle 304c is adjusted to match the central position of the inner needle 303a arranged inside the coaxial structure. By adjusting the central axis of the outer needle 304c with respect to the inner needle 303a in this way, the inner needle 303a and the outer needle 304c may be arranged coaxially or non-coaxially.

The diameter of the screw pin 306b is preferably 0.5 mm to 5 mm. The end of the screw pin 306b is preferably pointed or U-shaped. If the inner needle 303a and the outer needle 304c are arranged coaxially, the distance between the central axes of the inner needle 303 a and the outer needle 304 c is preferably adjusted to be less than 0.1 mm.

The outer diameter of the positioning unit body 306a is preferably 5 mm to 50 mm, and the inner diameter is 2 mm to 45 mm. The positioning unit body 306a may be made of any one of SUS metal, aluminum, brass, PEEK, acetal, and nylon. When the positioning unit body 306a is made of a conductive metal material, spinning stability may be achieved at the tip of the inner needle 303a by applying a high voltage to the outer needle positioning unit 306.

In the electrospinning nozzle 300 according to this embodiment, the inner diameter of the outer needle 304c is configured to be 5 μm to 1,000 μm larger than the outer diameter of the inner needle 303a. For example, in the electrospinning nozzle according to this embodiment, it is desirable that the inner needle 303a and the outer needle 304c have any one combination of 17G-23G [17G (OD: 1.47 mm, ID: 1.07 mm), 23G (OD: 0.63 mm, ID: 0.33 mm)], 17G-25G [17G (OD: 1.47 mm, ID: 1.07 mm), 25G (OD: 0.50 mm, ID: 0.25 mm)], 18G-25G [18G (OD: 1.27 mm, ID: 0.85 mm), 25G (OD: 0.50 mm, ID: 0.25 mm)], 21G-27G [21G (OD: 0.80 mm, ID: 0.50 mm), 27G (OD: 0.40 mm, ID: 0.20 mm)], and 22G-30G [22G (OD: 0.70 mm, ID: 0.40 mm), 30G (OD: 0.30 mm, ID: 0.15 mm)].

The air ejection unit 307 including a center hole 307d through which the outer needle 304c coaxially (or non-coaxially) surrounding the inner needle 303a passes and a plurality of gas discharge ports 307a is coupled with a fastening tubing 360c formed at the lower end of the positioning unit body 306a. A thin silicone plate 307d or an O-ring is installed in the center hole 307d, and the hollow screw 307b is tightened to seal the same. It is preferable that the length of the outer needle 304c protruding outside through the center hole 307d is 1 to 10 mm from the lower end of the air ejection unit 307.

The air ejection unit 307 according to this embodiment has completely the same configuration and function as the air ejection unit 104 illustrated in FIGS. 2 and 3 of the first embodiment.

Hereinafter, the operation of the electrospinning nozzle 300 according to this embodiment is described in detail.

First, the first spinning solution, which is the first fluid, is injected through the first fluid inlet 301a, and the spinning solution is ejected through the tip of the inner needle 303a. In addition, the second spinning solution, which is the second fluid, is injected through the second fluid inlet 302a, and is ejected to the outside through the outer needle 304c. At this time, as air is injected through the gas inlet 306d, the air is ejected through a plurality of gas ejection ports 307a provided in the air cap, which is the air ejection unit 307. The first spinning solution ejected from the inner needle 303a and the second spinning solution ejected from the outer needle 304c are generated as filament jets of a certain length through a conical Taylor cone, and then goes through a whipping mode in which the filament jet rapidly whips at a specific position, and as the solvent volatilizes, it is deposited as nanofibers on the collection unit.

The filament jet flies within a certain area of the air layer, and the air flow ejected from the gas discharge port 307a and moving in a straight line pushes the filament jet toward the collection unit within a certain distance from the filament jet, thereby forming an air flow layer moving in a straight line. Therefore, the filament jet may be suppressed from spreading out or dispersing excessively in the whipping mode. As a result, the spinning filament is laminated into a nanofiber web of a core-cell structure within a desired lamination area of the collection unit.

Third Embodiment

FIG. 5 is a cross-sectional view showing an electrospinning nozzle 400 according to the third embodiment of the present disclosure.

The electrospinning nozzle 400 according to the third embodiment of the present disclosure further includes a needle shaft 411 capable of controlling and blocking the flow of a spinning solution during an electrospinning process, in contrast to the electrospinning nozzle 100 of the first embodiment. That is, the electrospinning nozzle 400 according to this embodiment is substantially the same as the electrospinning nozzle 100 of the first embodiment, except that it additionally includes the needle shaft 411 in the configuration of the electrospinning nozzle 100 of the first embodiment. Therefore, the configuration of the electrospinning nozzle 400 of this embodiment that is the same as the electrospinning nozzle 100 of the first embodiment will not be described again in detail.

Referring to FIG. 5, the electrospinning nozzle 400 according to this embodiment includes an inner nozzle body 401 having a first fluid inlet 401a into which a first fluid is injected, an inner needle unit 403 connected to the inner nozzle body 401 and having a hollow tube-shaped inner needle 403b serving as an outlet of the first fluid, an outer nozzle body 402 including a second fluid inlet 402a into which gas serving as a second fluid is injected, an air inlet 410a into which air is injected, a needle shaft 411 for controlling and blocking the flow of the first fluid transferred to the inner needle unit 403, a pneumatic control unit body 410 including a needle shaft sealing portion 412 for preventing the first fluid from flowing backward and leaking to the upper portion of the needle shaft 411, a center hole 404a through which the inner needle 403b passes, an air ejection unit 404 including a plurality of gas discharge ports 404b provided at the periphery of the center hole 404a to eject gas (air) serving as a second fluid to the outside, and a high voltage applying unit 406 connected to the inner nozzle body 101.

Also, the electrospinning nozzle 400 of this embodiment may further include an outer needle unit having a hollow tube-shaped outer needle connected to the outer nozzle body 302 and arranged to coaxially surround the inner needle 403b, and an outer needle positioning unit including a plurality of screw pins for adjusting a central axis position of the outer needle, similar to the second embodiment.

The needle shaft 411 includes a taper blocking portion 411a that blocks a fluid passage toward the inner needle unit 403 to block the flow of the first fluid, and a shaft needle 411b having a pointed end that penetrates the inner needle 403b and protrudes through the front end thereof.

The needle shaft 411 is normally maintained in an upwardly raised state by the elastic restoring force of the spring 413 wound around the shaft. Accordingly, the fluid passage toward the inner needle unit 403 is in an opened state (ON state) so that the first fluid flows into the inner needle unit 403. In addition, when air is injected through the air inlet 410a, the spring 413 of the needle shaft 411 is compressed by the air pressure, and the taper blocking portion 411a at the tip of the needle shaft 411 blocks the fluid passage of the first fluid, and at the same time, the shaft needle 411b protrudes through the inner needle 403b to block the hollow space of the inner needle 403b.

Hereinafter, the operation of the electrospinning nozzle 400 of this embodiment is described in detail.

First, the spinning solution, which is the first fluid, is injected through the first fluid inlet 401a, and the spinning solution is ejected through the tip of the inner needle 403b. At this time, as air is injected through the second fluid inlet 402a, air is ejected through a plurality of gas ejection ports 404b provided in the air cap, which is the air ejection unit 404. The spinning solution ejected from the inner needle 403b passes through a conical Taylor cone to be generated as a filament jet of a certain length, and then goes through a whipping mode in which the filament jet rapidly whips at a specific position, and as the solvent volatilizes, it is deposited as nanofibers on the collection unit. Meanwhile, when the first fluid injected through the first inlet 401a is transferred to the inner needle unit 403, leakage of the first fluid due to backflow to the upper portion of the inner needle unit 403 is blocked by the sealing portion 412 of the needle shaft 411.

The filament jet flies within a certain area of the air layer, and the air flow ejected from the gas discharge port 404b and moving straight pushes the filament jet toward the collection unit within a certain distance, thereby preventing the filament jet from spreading out or dispersing excessively to the outside in the whipping mode. As a result, the spinning filament may be concentrated and deposited within a desired deposition area of the collection unit.

Meanwhile, as air is injected into the air inlet 410a, the spring 413 of the needle shaft 411 is compressed by the air pressure, the taper blocking portion 411a at the tip of the needle shaft 411 blocks the fluid passage of the first fluid, and at the same time, the shaft needle 411b penetrates the inner needle 403b and blocks the passage of the inner needle 403b, thereby blocking the flow of the spinning solution, which is the first fluid, and the electrospinning process is stopped. In order to resume the electrospinning process, the air injected into the air inlet 410a is blocked, and air is injected into the second fluid inlet 402a. As the air injected into the air inlet 410a is blocked, the spring 413 of the needle shaft 411 returns to its original position by the elastic restoring force, and the fluid passage of the inner needle unit 403 is switched to an open state, so that the electrospinning process is resumed.

In this way, the needle shaft 411 may simply perform ON/OFF control on the flow of the spinning solution injected into the first fluid inlet 401a.

In order to control the needle shaft 411, air injected from the outside through the air inlet 410a must be injected at a pressure greater than the elastic restoring force (tension) of the spring 413.

In addition, if the electrospinning nozzle 400 of this embodiment further includes an outer needle coaxially surrounding the inner needle 403b, a different spinning solution may be injected into the second fluid inlet 402a, and a separate gas inlet may be further included for injecting air that is to be ejected through the gas discharge port 404b.

Electrospinning Nozzle Block

FIG. 6 is a schematic perspective view showing the configuration of an electrospinning nozzle block to which the electrospinning nozzle according to the present disclosure is applied.

Referring to FIG. 6, the electrospinning nozzle block 200 according to a preferred embodiment of the present disclosure includes an inner space for accommodating a spinning solution transferred and injected from a solution storage tank (not shown), a nozzle body 230 having a plurality of solution distribution ports, an electrospinning nozzle 210 according to a selected one of the first embodiment, the second embodiment and the third embodiment, a nozzle adapter 220 for detachably coupling the electrospinning nozzle 210 to the nozzle body 230, and a high voltage applying unit 240 for applying high voltage electricity from a high voltage generating device 250 to the spinning solution accommodated in the inner space of the nozzle body 230.

The nozzle body 230 is a cylindrical pipe or a rectangular pipe having an inner space for accommodating a spinning solution introduced from a solution storage tank (not shown). Also, the nozzle body 230 may be configured as a rectangular container including an upper body and a lower body that may be separated from and combined with each other.

The inner space of the nozzle body 230 is used as a space to temporarily retain the spinning solution flowing from the solution storage tank while it is delivered to the electrospinning nozzle 210, or to temporarily store the spinning solution when the electrospinning process is temporarily stopped. The height of the inner space may be 1 mm to 30 mm, more preferably 3 mm to 10 mm, when used as a retention space, and may be 20 mm to 500 mm when used as a storage space.

It is preferable that the nozzle body 230 be made of an insulating material such as PEEK or a fluorine-based polymer (Teflon). The electrospinning nozzle 210 is detachably coupled to the nozzle body 230 through the nozzle adapter 220.

There are various ways to couple the electrospinning nozzle 210 to the nozzle adapter 220. The electrospinning nozzle 210 may be pushed up to the top of the nozzle adapter 220 and then fastened by turning the electrospinning nozzle 210 by 45 degrees to 360 degrees using a thin screw or a double-head screw, or the electrospinning nozzle 210 may be pushed up and then fixed by press-fitting.

The nozzle adapter 220 may be equipped with an ON/OFF valve capable of controlling the flow of the solution to prevent the spinning solution from leaking from the nozzle body 230 after the electrospinning nozzle 210 is separated.

The arrangement interval between the electrospinning nozzles 210 attached to the nozzle body 230 (the spacing between neighboring electrospinning nozzles) is 20 mm to 70 mm. More preferably, when the electrospinning nozzles 210 are arranged at a high density to mass-produce nanofibers, the arrangement interval between the electrospinning nozzles 210 is preferably 10 mm to 40 mm.

The material of the nozzle adapter 220 is preferably a fluorine-based material such as polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE), or a metal-based material such as stainless steel (SUS).

The high voltage applying unit 240 is a means for transmitting a high voltage from the high voltage generating device 250 to the spinning solution of the nozzle body 230, and includes a high voltage applying needle 241 corresponding to the electrospinning nozzle 210 in one-to-one relationship and a high voltage body 242 on which the high voltage applying needles 241 are arranged and fixed in a width direction (a direction perpendicular to the nozzle) at a constant width. The high voltage applying needle 241 is made of a metal having excellent electrical conductivity.

Accordingly, a plurality of holes 233 for passing the high voltage applying needle 241 through the nozzle body 230 are formed opposite to the side where the electrospinning nozzle 210 is coupled.

Therefore, the high voltage applying needle 241 penetrates the hole 233 and enters the inner space of the nozzle body 230, and charges the spinning solution retained or stored in the inner space with high voltage.

In addition, a hollow tube-shaped guide needle (not shown) may be further included to guide the high voltage applying needle 241 to stably enter the hole 233. The guide needle is disposed between the high voltage body 242 and the nozzle body 230 to guide the high voltage applying needle 241 to accurately enter the hole 233 of the nozzle body 230. Therefore, the inner diameter of the guide needle should be at least larger than the diameter (or outer diameter) of the high voltage applying needle 241.

The high voltage body 242 may be configured as a circular or rectangular rod made of SUS metal (hereinafter referred to as “metal rod”) that is electrically conductive inside an insulating cylindrical or rectangular pipe made of PEEK or PTFE fluorine-based material. The high voltage applying needle 241 is coupled to the metal rod in one-to-one relationship.

In addition, the high voltage body 242 may be configured as a cylindrical pipe or a rectangular pipe made of a current-conducting metal material, and a plurality of high voltage applying needles 241 may be press-fitted into the high voltage body 242. At this time, an adapter may be interposed, and the high voltage applying needles 241 may be configured as hub-type current-conducting needles so as to be detachable from the adapter.

The high voltage applying needle 241 is made of a highly electrically conductive material, like a hollow metal needle or a metal wire. The high voltage applying needle 241 may be arranged coaxially with the inner needle 103a, 303a, 403b of the electrospinning nozzle 210 or may be arranged coaxially with the solution storage space 101b of the inner nozzle body 101, 301, 401. At this time, it is preferable that the front end of the high voltage applying needle 241 is positioned 0 mm to 50 mm inside from the front end of the inner needle 103a, 303a, 403b.

In addition, the high voltage applying unit 240 may move up and down in the nozzle direction by a linear reciprocating mechanism 245.

Electrospinning Device

FIG. 7 is a perspective view showing a top-down roll-to-roll electrospinning device 500 in which a plurality of electrospinning nozzle blocks 200 of FIG. 6 are arranged in series.

For example, the top-down roll-to-roll electrospinning device 500 according to the present disclosure may be configured by sequentially arranging four electrospinning nozzle blocks 200 of FIG. 6, each of which has a unit length of 500 mm, in the width direction of the substrate (arrow A) to manufacture a wide nanofiber web having a wide width of at least 1,000 mm.

Referring to FIG. 7, the top-down roll-to-roll electrospinning device 500 according to the present disclosure includes an unwinder unit 501 serving as an unwinder for unwinding a roll on which a substrate is wound to spin a spinning solution and laminate nanofibers, a winder unit 502 serving as a winder for winding the substrate on which nanofibers are laminated, one or more (for example, three) nozzle block arrays 506 formed by sequentially connecting a plurality of (for example, four) electrospinning nozzle blocks 200 of FIG. 6 in the width direction (direction of arrow A) of the substrate, a collector 503 for transferring the substrate and laminating nanofibers spun from the at least one nozzle block array 506, and a solution storage tank (not shown) for storing the spinning solution.

In addition, the top-down roll-to-roll electrospinning device 500 of the present disclosure includes a solution transport mechanism having a plunger for pushing a solution in the solution storage tank and a solution transfer pump for precisely transferring the spinning solution to the spinning nozzle by operating the plunger, a high voltage power supply 507 for applying a high voltage to the spinning solution to impart a (+) or (−) polarity charge to the spinning solution in order to make the spinning solution discharged from the spinning needle of the electrospinning nozzle block 200 into fine fibers having a diameter of nanometers (nm) or micrometers (um), a robot driving unit 508 for reciprocating the nozzle block array 506 in the width direction of the substrate, a spinning distance adjustment unit 509 for moving the nozzle block array 506 up and down to adjust the distance between the collector 503 and the tip of the spinning needle, and a collection guide unit disposed at the left and right sides of the nozzle block array 506 in the direction in which the substrate is transferred to laminate the spun nanofibers into a limited area of the collector 503.

The collection guide unit controls the nanofibers spun from both ends of the spinning nozzle so as not to be pushed outward and spread out, and are collected in a limited internal area of the collector 503. To this end, a high voltage of the same polarity as the high voltage applied to the spinning solution may be applied to the collection guide unit, or a pneumatic airflow may be used.

In addition, the top-down roll-to-roll electrospinning device 400 of the present disclosure may further include a hot air generating device for evaporating a solvent from a large amount of spinning filaments spun from spinning needles of the nozzle block array 506 to create fine nanofibers, a humidity control device for controlling the solvent evaporation rate by adjusting the internal humidity of the electrospinning device 500, and a lamination device for controlling the coupling state of the nanofibers formed on the substrate.

In addition, the top-down roll-to-roll electrospinning device 500 of the present disclosure may further include a video camera that may monitor in real time the solidification state or clogging state of the spinning solution formed at the front end of the spinning needle or the droplet state of the Taylor cone formed at the tip of the spinning needle and store the same as a video or image. The video camera is provided at the bottom of the side surface of the nozzle block array 506 and moves back and forth to check the state of the front end of the spinning needle in real time or take an image.

The solution storage tank and the solution transfer pump according to the present disclosure may be coupled to each other into a single unit to push the solution of the solution storage tank. It is preferable that the solution storage tank has a dual structure in which the inside is made of SUS metal and the outside of the SUS metal is coated with a fluorine-based polymer or polyethylene (PE) or polypropylene (PP) as an outer material. The solution storage tank may be made of an insulating material such as polypropylene (PP), polyethylene (PE), polyetheretherketone (PEEK), MC nylon, or acetal with excellent voltage resistance. The capacity of the syringe-type solution storage tank is preferably 10 ml to 3,000 ml. Meanwhile, it is preferable that the plunger has a Teflon cover at the front end or a Teflon seal such as an omni seal to prevent the solution from leaking out through the rear surface of the plunger when the solution is pushed by the plunger.

The solution transfer pump includes a motor unit, a screw connected to the shaft of the motor, a pusher fastened to the screw and positioned inside the storage tank to push the plunger, a guide rod connecting the plunger and the pusher, a linear motion (hereinafter, LM) guide unit for smoothly moving the pusher in a linear motion, and a support unit for fastening and fixing the solution storage tank. The lead of the screw is 0.5 mm to 2 mm. Preferably, the lead of the screw is 1 mm. Regarding the movement speed of the pusher according to the rotation of the screw, a minimum speed is preferably 1 μm/hour to 100 μm/hour and a maximum speed is preferably 1 cm/minute to 20 cm/minute. The plunger is moved forward inside the barrel by external motor operation to extrude the solution. The plunger of the solution transfer pump may push the solution with air pressure without an external motor operation.

If the capacity of the solution storage tank is insufficient, two sets of solution transfer pumps may be provided in parallel and a three-way valve may be provided to transfer the solution. The flow direction of the valve is opened from the first solution pump to the spinning nozzle, and the second solution pump is kept closed. When the solution in the solution storage tank of the first transfer pump is completely exhausted, the direction of the valve is changed to close the first transfer pump and open the spinning nozzle from the second transfer pump. At this time, the solution transfer pump that is completely exhausted is refilled separately.

It is preferable for the spinning process to make nanofibers at a solution discharge rate of 0.5 μl/min to 1,000 μl/min per spinning needle. The preferable solution discharge rate is 5 μl/min to 300 μl/min. The applied high voltage is applied at 0.01 kV/cm to 10 kV/cm based on the distance (cm) between the tip of the spinning needle 111b and the collector 503. A more preferable high voltage is 0.5 kV/cm to 25 kV/cm.

The collector 503, which is a nanofiber collection unit, is configured as a plurality of rod rolls, or multi-wire rolls, or conveyor-type rolls, which may rotate together when the substrate moves and have a surface that is electrically conductive, and the rolls may be grounded or applied with a DC power having a polarity opposite to that of the charging solution. At this time, the intensity of the applied voltage having a polarity opposite to that of the solution is 1 kV to 20 kV. The substrate transfer speed is preferably 10 cm per minute to 50 m per minute.

In addition, it is preferable to perform a process of injecting hot air to volatilize the solvent into the atmosphere from the spinning filament emitted during spinning. At this time, the hot air from the hot air generating device is set to have a wind 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 preferably 30° C. to 80° C.

The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description.

INDUSTRIAL APPLICABILITY

A nanofiber web having fine pores may be manufactured by an electrospinning device to which the electrospinning nozzle block according to the present disclosure is applied, and the nanofiber web is utilized as a waterproof and moisture-permeable membrane, a filter medium for filtering ultrafine dust particles, a scaffold for cell culture, a drug-loading patch, a sensor material with a high specific surface area, and a flexible electronic material.