Apparatus for manufacturing melt-electrospun nanofibers

Abstract

The present invention relates to an apparatus for manufacturing melt-electrospun nanofibers and, more specifically, to an apparatus for manufacturing melt-electrospun nanofibers, which, in applying a method of directly supplying micro-filamentized thermoplastic polymer filaments to a spinning unit and instantaneously melting same for use rather than using conventional polymer chip-type raw materials, particularly enables the production of diverse high-value-added nanofiber products in small quantities through precise control of a filament feed rate, an instantaneous melting temperature at a nozzle unit, and voltage. In addition, the apparatus can provide customized thermoplastic polymer filaments suitable for various purposes by using not only medical biodegradable thermoplastic polymers but also industrial thermoplastic polymers, and particularly can maximize the durability of raw materials and workability thereof in a molten state, through separate melt-functional additives.

Description

Melt electrospinning nanofiber manufacturing device

[0001] The present invention relates to a melt-type electrospinning nanofiber manufacturing device, and more specifically, to a melt-electrospinning nanofiber manufacturing device that applies a method of directly supplying a finely filamentized thermoplastic polymer filament to a spinning unit and instantly melting it, rather than a conventional polymer chip-type raw material, and in particular, precisely controlling the filament supply speed, the instantaneous melting temperature at the nozzle unit, and the voltage, thereby enabling the production of small-quantity, high-value-added nanofiber products in a variety of varieties, and further enabling the provision of customized thermoplastic polymer filaments for various purposes by utilizing not only medical biodegradable thermoplastic polymers but also industrial thermoplastic polymers, and in particular, maximizing the durability of the raw material and the workability in a molten state through a separate melting functional additive.

[0002] Nanofibers are widely used in products such as nonwoven fabrics, membranes, and blades, and are widely used in household goods, agriculture, clothing, and industrial applications. Specifically, they are used in a wide range of fields, including artificial leather, artificial suede, sanitary napkins, clothing, diapers, packaging materials, miscellaneous goods, various filter materials, medical materials for gene delivery systems, and defense materials such as bulletproof vests.

[0003] Conventionally, an electric solution spinning device has been commonly used as a method for manufacturing such nanofibers. This is done by applying a voltage higher than the surface tension to a polymer solution, spraying the polymer solution, increasing the instability of the fluid within the electric field, causing bending and splitting of the polymer solution, thereby nanofiberization and forming fibers on a collecting plate. However, the solvent used in the polymer solution is mainly dimethylformamide (DMF), a solvent, etc., and the solvent is a colorless liquid with a gasoline odor and is highly flammable, so there is a problem of fire caused by electric sparks, etc., and when inhaled, symptoms such as dizziness, nausea, and vomiting are caused, and when inhaled, high concentrations of vapor are inhaled, such as loss of consciousness or fainting, and there are problems that are harmful to the human body. In addition, the DMF has a risk of damaging the liver, can cause cancer, can cause skin diseases, and can cause symptoms such as lethargy, dizziness, headache, abdominal pain, nausea, vomiting, and constipation. Therefore, it is a hazardous substance whose use is regulated in developed countries. Therefore, this electric solution spinning method exposes various problems due to the use of harmful solvents. In addition, the electric solution spinning described above has problems such as limitations in production quality because only polymers that are soluble in the solvent can be used, and there is a risk of explosion due to the solvent when electricity is applied.

[0004] To improve the problems of these electrospinning solutions, electrospinning devices that melt and spin polymers without using solvents have recently been developed.

[0005] However, in the case of existing devices applied to such electric melt spinning, raw materials are fed in the form of polymer chips, and separate components such as a heating means for heating them, a structure for transporting the molten raw materials, and a chamber (tank) for storing them are required, so the structure of the raw material supply section and the spinning section is complex and takes up a large volume. In addition, during the melting process of raw materials in the form of polymer chips, they must be heated at a high temperature, and to do this, high voltage is used, so the extruder drive motor may be damaged by the high voltage, and to prevent this, separate insulation and heat-resistant design must be reflected, which causes the problem of increasing the overall manufacturing cost.

[0006] Patent Document

[0007] Registered Patent No. 10-2022033 (announced on September 18, 2019) "Electric Melting Spinning Device"

[0008] Patent No. 10-1846823 (announced on April 9, 2018) "Mass-production melt electrospinning device for nanofibers and solvent-free melt electrospinning method"

[0009] The prior art technologies disclosed in the above-mentioned <patent documents> are also patents regarding an electric melt spinning device developed to improve the problems of the existing electric solution spinning, and the structure of the electric melt spinning device disclosed in the above-mentioned <patent documents> is the same as the existing structure in that it has a structure for melting, transporting, storing, and insulating the raw material in the form of polymer chips mentioned above (referring to FIG. 1, the configuration of the polymer chip inlet (12) and the melting furnace (10) in the above-mentioned 033 patent, and referring to FIG. 2, the configuration of the melt extrusion polymer supply unit (100) including the inlet (110) for feeding the polymer chip, the screw (130) for transporting the polymer melt, and a plurality of heating units in the above-mentioned 823 patent), and there is an increasing need for a device having a new configuration and structure that can solve the problems of the complicated structure of the raw material supply unit and the spinning unit of the existing electric melt spinning device, taking up a large volume, and the increased manufacturing cost for separate insulation design, etc.

[0010] The present invention has been devised to solve the above problems.

[0011] The purpose of the present invention is to provide a new structure of a melt electrospinning nanofiber manufacturing device that can simplify and miniaturize the structure of the raw material supply unit and the spinning unit and can easily manufacture molten nanofibers with a small amount of raw material by applying a method of supplying microfilament thermoplastic polymer filaments directly to the spinning unit and melting them instantly, rather than using raw materials in the form of existing polymer chips.

[0012] Another object of the present invention is to provide a melt electrospinning nanofiber manufacturing device which is advantageous for manufacturing small-quantity, high-value-added nanofiber products by precisely controlling the supply speed of thermoplastic polymer filament raw material through a feeder, precisely controlling the melting temperature of a nozzle section where the thermoplastic polymer filament is instantly melted through the control of an induction heating section, and precisely controlling the voltage between the nozzle and the collector section through the control of a power control section to instantly melt only a small amount of the filament raw material and manufacture nanofibers, thereby enabling melt electrospinning to be implemented with a short and simple cleaning and spinning preparation process.

[0013] Another object of the present invention is to provide a melt electrospinning nanofiber manufacturing device capable of providing customized thermoplastic polymer filaments for various purposes by utilizing not only medical biodegradable thermoplastic polymers but also industrial thermoplastic polymers, and in particular, capable of maximizing the durability of raw materials and workability in a molten state through a separate melt functional additive.

[0014] Another object of the present invention is to provide a melt electrospinning nanofiber manufacturing device that fundamentally blocks heat from the radiation section from being transferred to the raw material supply section by configuring a separate cooling section and heat blocking pipe section between the raw material supply section and the radiation section, thereby allowing fine filamentary thermoplastic polymer filaments to be stably supplied to the radiation section without melting before being supplied to the radiation section.

[0015] In order to achieve the above-mentioned purpose, the present invention is implemented by an embodiment having the following configuration.

[0016] According to one embodiment of the present invention, a melt electrospinning nanofiber manufacturing device according to the present invention comprises: a raw material supply unit into which a thermoplastic polymer raw material is input; a spinning unit that melts the raw material supplied from the raw material supply unit and spins it through a nozzle; a collector unit that collects the nanofibers spun through the nozzle; and a control unit that controls a melt electrospinning process, wherein the thermoplastic polymer raw material is a thermoplastic polymer filament that is filamentized and supplied long and continuously in a customized manner according to the diameter of the nozzle, and the raw material supply unit includes a filament feeder that precisely controls the supply speed or amount of the thermoplastic polymer filament that is filamentized and supplied long and continuously, and the spinning unit includes an induction heating unit that is directly connected to a nozzle inlet and melts the supplied thermoplastic polymer filament by a non-contact induction heating method, and a power control unit that applies a voltage between the nozzle and the collector unit.

[0017] According to another embodiment of the present invention, in the present invention, the control unit includes a feeder control module that controls the supply speed or supply amount of thermoplastic polymer filaments supplied through the filament feeder, a heating control module that controls the melting temperature of the thermoplastic polymer filaments in the nozzle through control of the induction heating unit, and a voltage control module that controls the voltage between the nozzle and the collector unit through the power control unit, wherein the feeder control module controls the supply speed of the thermoplastic polymer filaments within a range of 0.001 to 0.01 cc / m, the heating control module controls the nozzle temperature within a range of 220 to 380°C, and the voltage control module controls the voltage between the nozzle and the collector unit within a range of 18 to 100 kV.

[0018] According to another embodiment of the present invention, the thermoplastic polymer filament in the present invention is a medical biodegradable thermoplastic polymer filament, characterized in that it includes at least one selected from the group consisting of polyethylene oxide (PDO), polylactide (PLA), polyglycolide (PGA), and polycaprolactone (PCL).

[0019] According to another embodiment of the present invention, the thermoplastic polymer filament in the present invention is an industrial thermoplastic polymer filament, and comprises at least one selected from the group 2-1 consisting of polyurethane, polyvinylidene fluoride, polyacetal, polyester, polycarbonate, polysulfone, polyetherimide, polyamideimide, polyphenylene sulfonate, polystyrene, polypropylene, vinyl chloride, vinyl chloride acrylonitrile copolymer, ethylene vinyl chloride copolymer, propylene vinyl chloride copolymer, vinyl acetate, polyvinyl alcohol, and polyamide, and ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, acrylonitrile-butadiene styrene copolymer, acrylonitrile-styrene copolymer, vinyl chloride vinyl chloride acetate copolymer, vinyl acetate maleate copolymer, vinyl chloride vinyl acetate copolymer, It is characterized by including at least one from group 2-2 consisting of vinyl chloride vinylidene chloride copolymer, vinyl acrylonitrile chloride copolymer, ethylene vinyl chloride copolymer, and propylene vinyl chloride copolymer.

[0020] According to another embodiment of the present invention, the thermoplastic polymer filament in the present invention comprises a melting functional additive, and the melting functional additive is characterized in that it comprises at least one from group 3-1 consisting of polydimethylsiloxane (PDMS) and polyethylene glycol (PEG), at least one from group 3-2 consisting of stearic acid (SA), oleic acid (OA), citric acid (CA), propionic acid (PA), and gallic acid (GA), and at least one from group 3-3 consisting of alizarin, quercetin, chitosan, and epicatechin.

[0021] According to another embodiment of the present invention, the raw material supply unit in the present invention is characterized in that it further includes a cooling unit formed with cooling fins including a separate fan between the filament feeder and the induction heating unit to rapidly cool the heat generated in the induction heating unit and directed to the raw material supply unit, and a heat blocking pipe unit formed on the inside of the pipe above the induction heating unit in a pipe supplying a thermoplastic polymer filament to the nozzle inlet to prevent the heat generated in the induction heating unit from being transferred to the raw material supply unit through the pipe.

[0022] According to another embodiment of the present invention, the heat-insulating pipe part in the present invention comprises 100 parts by weight of a metal oxide mixed with aluminum-doped zinc oxide and tungsten oxide selected from barium tungsten oxide, lithium tungsten oxide, and cesium tungsten oxide, 5 to 10 parts by weight of a first functional additive for preventing shrinkage even when temperature changes rapidly, and 5 to 10 parts by weight of a second functional additive for enhancing chemical resistance, wherein the first functional additive comprises 80 to 95 parts by weight of sodium metasilicate, 5 to 10 parts by weight of sodium gluconate, and 1 to 5 parts by weight of a thickener, and the second functional additive comprises 1 to 5 parts by weight of a silane compound, 1 to 5 parts by weight of calcium nitrate, 1 to 5 parts by weight of nanoceramic particles, 1 to 5 parts by weight of graphene, and 1 to 5 parts by weight of mica.

[0023] The present invention can obtain the following effects through the combination and use of the configuration described below with the previously described embodiment.

[0024] The present invention applies a method of supplying a thermoplastic polymer filament in the form of a fine filament directly to a spinning unit and melting it instantly, rather than a raw material in the form of a conventional polymer chip, thereby simplifying and miniaturizing the structure of the raw material supply unit and the spinning unit, and having the effect of easily manufacturing a molten nanofiber with a small amount of raw material.

[0025] The present invention precisely controls the supply speed of a thermoplastic polymer filament raw material through a feeder, precisely controls the melting temperature of a nozzle section where the thermoplastic polymer filament is instantly melted through the control of an induction heating section, and precisely controls the voltage between the nozzle and the collector section through the control of a power control section to instantly melt only a small amount of the filament raw material to manufacture nanofibers, thereby enabling melt electrospinning to be implemented with a short and simple cleaning and spinning preparation process, which has an advantageous effect in manufacturing small-quantity, high-value-added nanofiber products.

[0026] The present invention can provide customized thermoplastic polymer filaments for various purposes by utilizing not only medical biodegradable thermoplastic polymers but also industrial thermoplastic polymers, and in particular, has the effect of maximizing the durability of raw materials and workability in a molten state through a separate melting functional additive.

[0027] The present invention has the effect of fundamentally blocking heat from the radiation section from being transferred to the raw material supply section by configuring a separate cooling section and heat-blocking pipe section between the raw material supply section and the radiation section, thereby allowing the finely filamentized thermoplastic polymer filament to be stably supplied to the radiation section without melting before being supplied to the radiation section.

[0028] Figure 1 is a structural diagram of the prior art 033 patent.

[0029] Figure 2 is a structural diagram of the prior art patent 823.

[0030] Figure 3 is a block diagram of a melt electrospinning nanofiber manufacturing device according to one embodiment of the present invention.

[0031] Figure 4 is a reference diagram of a melt electrospinning nanofiber manufacturing device according to one embodiment of the present invention.

[0032] Hereinafter, preferred embodiments of a melt electrospinning nanofiber manufacturing device according to the present invention will be described in detail with reference to the attached drawings. It should be noted that, as much as possible, identical components are represented by the same reference numerals throughout the drawings. Unless otherwise defined, all terms in this specification have the same general meaning as those terms understood by a person skilled in the art to which the present invention pertains, and if there is a conflict with the meaning of a term used in this specification, the definitions used in this specification shall apply. Throughout the specification, when a part is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components may be further included, unless specifically stated otherwise. In addition, terms such as "... part" and "... module" described in the specification mean a unit that processes at least one function or operation, and this may be implemented by hardware, software, or a combination of hardware and software.

[0033]

[0034] Referring to FIGS. 3 and 4, a melt electrospinning nanofiber manufacturing device according to one embodiment of the present invention includes a raw material supply unit (10) into which a thermoplastic polymer raw material is supplied; a spinning unit (30) that melts the raw material supplied from the raw material supply unit (10) and spins it through a nozzle (310); a collector unit (50) that collects nanofibers spun through the nozzle (310); and a control unit (70) that controls the melt electrospinning process. The thermoplastic polymer raw material is characterized in that it is a thermoplastic polymer filament (1) that is filamentized in a customized manner according to the diameter of the nozzle (310) (i.e., the raw material is supplied in the form of a single thin, long line) and is supplied in a long and continuous manner.

[0035] The above raw material supply unit (10) is configured to supply a meltable thermoplastic polymer raw material for manufacturing nanofibers through the melt electrospinning nanofiber manufacturing device of the present invention. As previously mentioned as a problem of the prior art, in the conventional melt spinning type electrospinning device, the raw material is fed in the form of polymer chips, and separate components such as a heating means for heating the raw material, a component for transporting the molten raw material, and a chamber (tank) for storing the raw material are required. Therefore, the structure from the raw material supply component to the spinning unit is complex and takes up a large volume. In addition, the heater that must be heated to a high temperature during the melting process of the raw material in the form of polymer chips, or the compressor that transports the molten raw material, etc. are easily damaged by high voltage due to the nature of electrospinning, and to prevent this, a separate insulation and heat-resistant design must be reflected, so that the overall manufacturing cost increases. In the present invention, the thermoplastic polymer raw material fed for manufacturing nanofibers is supplied by forming it into a thermoplastic polymer filament (1) that is customized according to the diameter of the nozzle (310) and supplied long and continuously. Do it.

[0036] To this end, the raw material supply unit (10) includes a filament feeder (110) that precisely controls the supply speed or supply amount of a thermoplastic polymer filament (1) that is filamentized and supplied long and continuously. The filament feeder (110) precisely controls the supply speed, etc., at which the thermoplastic polymer filament (1) that is filamentized and supplied long and continuously into a thin and long shape is supplied to the nozzle (310) of the spinning unit (30) to be described later, thereby precisely controlling the supply amount of the raw material according to the amount of nanofibers to be spun. To this end, the filament feeder (110) may be configured to utilize a feeding roller, a feeding motor, a control controller, etc. capable of precisely controlling the supply speed, etc., according to the supply direction of the thermoplastic polymer filament (1) that is continuously supplied in a thin and long form, and precise control of the filament feeder (110) is performed through a feeder control module () of a control unit () described later.

[0037] In this way, the thermoplastic polymer filaments (1) that are continuously supplied in a thin shape with a diameter of about 0.1 to several mm in size (proportional to the diameter of the nozzle (310) inlet) to match the diameter of the nozzle (310) that melt-spun the raw material for manufacturing nanofibers are supplied to the nozzle (310) inlet side by the filament feeder (110) preferably in a straight line, and the supply speed, etc. are precisely controlled so that the supply amount is precisely controlled according to the amount of nanofibers spun through the nozzle (310). In addition, since the thermoplastic polymer filaments (1) remaining after the spinning process are easy to recover and can be reused in the future, waste of raw materials can be minimized.

[0038] Meanwhile, as an example of a thermoplastic polymer filament applicable to the present invention, a medical biodegradable thermoplastic polymer filament is utilized, and may include at least one selected from the group consisting of polyethylene oxide (PDO), polylactide (PLA), polyglycolide (PGA), and polycaprolactone (PCL). That is, in the present invention, a biodegradable polymer filament usable for medical purposes is provided directly to a nozzle (310) even in a small amount and can be melt-spun into a product, and further, the minimum remaining amount can be recovered and reused, so it is particularly suitable for the production of expensive, small-quantity, high-value-added nanofiber products for medical use.

[0039] In addition, as another example of a thermoplastic polymer filament applicable to the present invention, an industrial thermoplastic polymer filament is utilized, and at this time, the industrial thermoplastic polymer filament particularly includes at least one selected from the group 2-1 consisting of polyurethane, polyvinylidene fluoride, polyacetal, polyester, polycarbonate, polysulfone, polyetherimide, polyamideimide, polyphenylene sulfonate, polystyrene, polypropylene, vinyl chloride, vinyl acetate, polyvinyl alcohol, and polyamide, and ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, acrylonitrile-butadiene styrene copolymer, acrylonitrile-styrene copolymer, vinyl chloride vinyl chloride acetate copolymer, vinyl acetate maleate copolymer, vinyl chloride vinyl acetate copolymer, vinyl chloride vinylidene chloride copolymer, It is characterized by comprising at least one member from the 2-2 group consisting of a vinyl acrylonitrile chloride copolymer, an ethylene vinyl chloride copolymer, and a propylene vinyl chloride copolymer.

[0040] That is, due to the nature of industrial nanofiber products that are utilized for various purposes, the final properties of industrial nanofibers must be able to be customized and produced to suit various purposes. In order to enable the raw material used for the production of such industrial nanofibers, i.e., industrial thermoplastic polymer filaments, to have various properties adjusted to suit these characteristics, the industrial thermoplastic polymer filaments of the present invention are characterized in that they are used as raw materials for industrial thermoplastic polymer filaments by blending at least one base material suited to the characteristics of each use from the 2-1 group consisting of pure thermoplastic polymers, and at least one copolymer material manufactured to exhibit properties suited to the characteristics of each use from the 2-2 group consisting of thermoplastic polymer copolymers capable of adjusting various properties to suit needs by chemically linking two or more monomers into one polymer. In other words, it is characterized by supplying industrial thermoplastic polymer filament raw materials having customized characteristics (physical properties) by blending, in addition to the basic thermoplastic polymer filament material of the base material, a thermoplastic polymer copolymer whose physical properties have been adjusted according to the characteristics of each use.

[0041] In particular, the thermoplastic polymer filament applied to the present invention additionally includes a melting functional additive, which maximizes the durability of the raw material and workability in a molten state. For this purpose, the melting functional additive is characterized by including at least one from group 3-1 consisting of polydimethylsiloxane (PDMS) and polyethylene glycol (PEG), at least one from group 3-2 consisting of stearic acid (SA), oleic acid (OA), citric acid (CA), propionic acid (PA), and gallic acid (GA), and at least one from group 3-3 consisting of alizarin, quercetin, chitosan, and epicatechin.

[0042] First, the additive material of the above 3-1 group is a base material that exhibits the basic melting properties of functional additives while having soft properties suitable for melting and excellent thermal stability. In particular, polydimethylsiloxane (PDMS) and polyethylene glycol (PEG) can be applied. Polydimethylsiloxane (PDMS) is structurally flexible and has soft properties while having excellent thermal stability, and has the characteristic of being able to exhibit various properties depending on the molecular weight and degree of crosslinking. Polyethylene glycol (PEG) also has the characteristic of being able to stably combine with other functional additives and exhibit various properties based on its flexible properties and stability.

[0043] And, the additive materials of the above 3-2 group can be applied such as stearic acid (SA), oleic acid (OA), citric acid (CA), propionic acid (PA), gallic acid (GA), etc., and these materials have the characteristic of being able to exhibit properties that not only improve the physical and mechanical properties (characteristics) of the thermoplastic polymer filament raw materials (materials) of the present invention but also improve the stability of crosslinking and mixing with other functional additives.

[0044] Lastly, the additive materials of the third group can be applied, such as alizarin, quercetin, chitosan, and epicatechin. In the case of alizarin, it has excellent thermal stability and is stable against air and light, and can enhance the properties of fibers / fabric while also improving conductivity. In the case of quercetin, chitosan, and epicatechin, it has the property of improving conductivity and the property of improving stability with other additive components.

[0045] Accordingly, in the thermoplastic polymer filament applied to the present invention, by additionally including melting functional additive components having various characteristics as described above, it is possible to improve the physical and mechanical properties (characteristics) of the thermoplastic polymer filament raw materials (materials), as well as improve the safety and melting properties, thermal stability, and conductivity of crosslinking and mixing between materials.

[0046] The above-mentioned radiation unit (30) is configured to melt the raw material supplied from the raw material supply unit (10) and to radiate it through the nozzle (310). In particular, the present invention is characterized by a structure in which a thermoplastic polymer filament (1) supplied in a filament form and directly connected to the radiation unit (30) is instantly melted and radiated at the front end of the nozzle (310) (i.e., immediately before being radiated through the nozzle (310)). To this end, the radiation unit (30) may include an induction heating unit (320) that melts the thermoplastic polymer filament (1) supplied by being directly connected to the inlet of the nozzle (310) using a non-contact induction heating method, and a power control unit (330) and a tilting unit (340) that apply voltage between the nozzle (310) and the collector unit (50).

[0047] The above induction heating unit (320) is configured to convert the thermoplastic polymer filament (1) supplied by being directly connected to the nozzle (310) inlet into a molten state before being radiated through the nozzle (310). In particular, the induction heating unit (320) can apply a non-contact induction heating method so as to convert the supplied thermoplastic polymer filament (1) into a molten state before being radiated through the nozzle (310). That is, for example, by using a heating coil that surrounds the nozzle (310) in a non-contact manner and a configuration that applies and controls a high-frequency current to the heating coil, the nozzle (310) and the nozzle (310) inlet are instantaneously inductively heated to a temperature range of about 220 to 380° C., so that the thermoplastic polymer filament (1) supplied by being directly connected to the nozzle (310) inlet is instantaneously converted into a molten state before being radiated through the nozzle (310) and radiated through the nozzle (310). That is, in the present invention, since the polymer raw material supplied for electrospinning is supplied to the nozzle (310) in the form of thin and long filaments, the thermoplastic polymer filament (1) can be melted and spun instantaneously in a short section only through the configuration of the induction heating unit (320) around the nozzle (310).

[0048] At this time, the raw material supply unit (10) includes components that fundamentally block the heat generated in the induction heating unit (320) from being transferred to the upper side thereof, i.e., the raw material supply unit (10) (i.e., so that the fine filament thermoplastic polymer filaments can be stably supplied to the spinning unit without being melted until they are supplied to the spinning unit), and may additionally include a cooling unit (120) formed between the filament feeder (110) and the induction heating unit (320) to prevent the heat generated in the induction heating unit (320) from being transferred to the raw material supply unit (10), and a heat blocking pipe unit (130) formed inside the pipe on the upper side of the induction heating unit (320) in the pipe that supplies the thermoplastic polymer filament to the nozzle inlet to prevent the heat generated in the induction heating unit (320) from being transferred to the raw material supply unit (10) through the pipe. That is, if the heat of the induction heating unit (320) for melting the raw material around the nozzle (310) is transferred to the upper side, it may cause deformation of the thermoplastic polymer filament (1) that is fine and long, and this may cause problems such as difficulty in precisely controlling the amount of thermoplastic polymer filament (1) supplied from the raw material supply unit (10). To prevent this, the heat generated through the cooling unit (120) and the heat blocking pipe unit (130) configured above the induction heating unit (320) is blocked from being transferred to the upper side, that is, the upper side of the induction heating unit (320).

[0049] To this end, the cooling unit (120) may preferably be formed as a cooling fin including a separate fan (not shown). That is, not only is the area dissipated by the cooling fins maximized to increase the cooling efficiency, but the fan configuration further increases the cooling efficiency, thereby efficiently and rapidly cooling the heat generated from the induction heating unit (320) and directed upward, so that no problem occurs due to heat transfer to the thermoplastic polymer filament (1) on the upper side of the induction heating unit (320).

[0050] In addition, the heat-insulating pipe section (130) is formed on the inside of the pipe above the induction heating section (320) in the pipe that supplies the thermoplastic polymer filament to the nozzle inlet, and is configured to prevent heat generated in the induction heating section (320) from being transmitted to the raw material supply section (10) through the pipe. To this end, the heat-insulating pipe section (130) is characterized in that it comprises 100 parts by weight of a metal oxide mixed with aluminum-doped zinc oxide and tungsten oxide selected from barium tungsten oxide, lithium tungsten oxide, and cesium tungsten oxide, 5 to 10 parts by weight of a first functional additive for preventing shrinkage even when the temperature changes rapidly, and 5 to 10 parts by weight of a second functional additive for enhancing chemical resistance, in order to exhibit characteristics for heat-insulating and enhancing durability.

[0051] That is, as a base material for the heat blocking functionality to prevent the heat generated in the induction heating section (320), which is the basic characteristic of the heat blocking pipe section (130), from being transferred to the raw material supply section (10) through the pipe, a metal oxide in which aluminum-doped zinc oxide and tungsten oxide are mixed is utilized. In addition to the aluminum-doped zinc oxide having the basic heat blocking properties, tungsten oxide selected from barium tungsten oxide, lithium tungsten oxide, and cesium tungsten oxide is additionally mixed (a preferred mixing ratio is 70 to 90 parts by weight of aluminum-doped zinc oxide and 10 to 30 parts by weight of tungsten oxide), thereby maximizing the heat blocking functionality.

[0052] In addition, the first functional additive is a functional additive for preventing shrinkage, that is, improving the physical durability of the heat insulation pipe section (130) itself even in the event of a rapid temperature change in the heat insulation pipe section (130), and more specifically, may include 80 to 95 parts by weight of sodium metasilicate, 5 to 10 parts by weight of sodium gluconate, and 1 to 5 parts by weight of a thickener.

[0053] The above sodium metasilicate (Na2SiO3) is a substance that dissolves well in water and has viscous, sticky, and dense properties. By mixing it with various components such as the metal oxide in an appropriate amount, it provides appropriate viscosity to the heat insulation pipe section (130) itself, thereby improving resistance to phenomena such as separation between materials.

[0054] The above sodium gluconate (C6H11NaO7) performs the function of increasing the physical durability of the material itself even under rapid temperature changes of the heat insulation pipe section (130).

[0055] The above thickener performs the function of increasing resistance to separation phenomena between materials of the heat insulation pipe section (130). Methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polysaccharide, etc. can be used as the above thickener.

[0056] In addition, the second functional additive is a functional additive for chemical durability, i.e., chemical resistance, of the heat-insulating pipe section (130) itself even when in contact with various raw materials in the heat-insulating pipe section (130), and more specifically, may include 1 to 5 parts by weight of a silane compound, 1 to 5 parts by weight of calcium nitrate, 1 to 5 parts by weight of nanoceramic particles, 1 to 5 parts by weight of graphene, and 1 to 5 parts by weight of mica.

[0057] As the above silane compound, for example, perfluoroalkoxysilanes such as perfluoromethoxysilane and perfluoroethoxysilane, tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane, dialkoxysilane, silane oxide, alkoxysilane, silane oxide, or a mixture thereof can be utilized. In particular, the silane compound increases the chemical resistance, etc., of the composition in which it is included, and improves the thermal stability and mechanical properties, thereby increasing the durability, etc., of the heat insulation pipe section (130), and assists in organic mixing between components in the composition.

[0058] The above calcium nitrate is used to form a calcium-based zinc phosphate film, and can improve surface properties such as wear resistance and corrosion resistance by refining the film crystals.

[0059] The above nanoceramic particles rise to the surface of the heat insulation pipe section (130) to form a dense and hard surface, so that they can particularly improve chemical resistance, etc. Preferred nanoceramic particles may include silicon carbide, alumina, silica, zirconia-silica, ZnO, TiO2 and / or CaCO3.

[0060] The above graphene is one of the carbon allotropes and has a structure composed of a honeycomb lattice of atomic units and is a material used as a water treatment filter for seawater desalination. This graphene can provide chemical resistance such as corrosion resistance in particular and also increase the durability of the heat insulation pipe section (130) through its plate-like structure.

[0061] The above mica is a mineral existing in rocks and is a material that is resistant to heat and, in particular, has excellent electrical insulation properties. Through this mica, the electrical insulation properties in the heat insulation pipe section (130), that is, the electrical insulation function between the induction heating section (320) and the raw material supply section (10), are strengthened while also exhibiting the effect of being able to exhibit a heat blocking function.

[0062] Meanwhile, a configuration (not shown) for supplying hot air around the nozzle (310) and spraying it around the nozzle may be additionally included, and a structure may be applied in the form of a pipe that sprays hot air of about 200° C. in the direction in which the nanofibers are sprayed through the nozzle (310) around the nozzle (310) in order to enable air-blowing that enables elongation and thickness control of the nanofibers sprayed through the nozzle (310).

[0063] The power control unit (330) is configured to apply an electric field to the nozzle (310) by applying a voltage (for example, a voltage of about 20 to 30 kV) between the nozzle (310) and the collector unit (50) under the precise control of the control unit (70) described later. When the electric field is applied to the nozzle (310), the polymer raw material that is discharged in a molten state through the nozzle (310) is radiated to form nanofibers, and the radiated nanofibers are collected in the collector unit (50) described later to be manufactured. In particular, in the present invention, since the configuration for melting the raw material in the raw material supply section (10) and the spinning section (30) is simplified to the induction heating section (320) around the nozzle (310) by using a thermoplastic polymer filament (1) that is a thin and long filament raw material, a relatively lower voltage can be applied compared to the existing melt spinning structure (a configuration for heating during the process of melting, transporting, storing, etc. of the raw material in the form of a polymer chip), and thus the melt electrospinning system can be applied more safely.

[0064] The above tilting unit (340) is configured to allow the nozzle (310) from which nanofibers are emitted to move in various directions, thereby enabling the production of uniform nanofibers. That is, if the tilting unit (340) is formed so that the nozzle (310) from which nanofibers are emitted can be periodically moved in various directions, such as left and right or back and forth, as needed, rather than being fixed, the emitted nanofibers can be more uniformly stacked on the collecting plate during the dust collection process. The tilting unit (340) can enable various directional changes, such as by applying movement to the radiating unit (30) itself, including the nozzle (310), or by applying movement to the entirety, including the radiating unit (30) and the raw material supply unit (10).

[0065] The above collector unit (50) is configured to collect and gather nanofibers emitted through the nozzle (310), and in particular, in the present invention, while collecting and stacking nanofibers emitted on a metal collector plate, it can also perform the function of efficiently stacking nanofibers emitted through the nozzle (310) onto the collector plate through a separate suction unit (air-suction) (not shown) configured under the collector plate, while also enabling control of the thickness of the nanofibers. The distance between the nozzle (310) and the collector unit (50) can vary depending on the type of nanofibers to be commercialized, but a distance of approximately several tens of cm is preferable.

[0066] The above control unit (70) is configured to precisely control the melt electrospinning process, and for this purpose, more specifically, the control unit (70) may include a feeder control module (710) that controls the supply speed or supply amount of the thermoplastic polymer filament (1) supplied through the filament feeder (110), a heating control module (720) that controls the melting temperature of the thermoplastic polymer filament (1) in the nozzle through control of the induction heating unit (320), and a voltage control module (730) that controls the voltage between the nozzle (310) and the collector unit (50) through the power control unit (330).

[0067] The above feeder control module (710) is configured to control the supply speed or supply amount of thermoplastic polymer filament (1) supplied through the filament feeder (110), and more specifically, by controlling the supply speed of the thermoplastic polymer filament within the range of 0.001 to 0.01 cc / m, it enables a small amount of filament raw material to be sufficiently and quickly melted and spun during the instantaneous supply process.

[0068] The above heating control module (720) is configured to control the melting temperature of the thermoplastic polymer filament (1) in the nozzle by controlling the induction heating unit (320). More specifically, by controlling the nozzle temperature within the range of 220 to 380°C, the supplied thermoplastic polymer filament (1) is instantly melted around the nozzle, thereby enabling rapid and accurate melt spinning while minimizing waste of raw materials.

[0069] The above voltage control module (730) is configured to control the voltage between the nozzle (310) and the collector unit (50) through the power control unit (330), and more specifically, it controls the voltage between the nozzle and the collector unit within the range of 18 to 100 kV, thereby enabling relatively simple melt electrospinning.

[0070] The melt electrospinning nanofiber manufacturing device of the present invention having such a configuration applies a method of directly supplying a finely filamentized thermoplastic polymer filament (1) to the spinning unit (30) instead of a conventional polymer chip-type raw material and instantly melting and spinning it around a nozzle (310), thereby simplifying and miniaturizing the structure of the raw material supply unit (10) and the spinning unit (30), and easily manufacturing a melt nanofiber with a small amount of raw material, and in particular, by precisely controlling the supply amount of the thermoplastic polymer filament (1) raw material through the filament feeder (110) and instantly melting only a small amount of the filament raw material by an induction heating method to manufacture the nanofiber, the cleaning and spinning preparation process is short, which is particularly advantageous in manufacturing small quantities of high-value-added nanofiber products, and in addition, melt electrospinning can be implemented using a relatively low voltage compared to the conventional one, so that it has the characteristic of being able to work more safely.

[0071]

[0072] In the above, the applicant has described various embodiments of the present invention, but such embodiments are only examples of implementing the technical idea of ​​the present invention, and any change or modification that implements the technical idea of ​​the present invention should be interpreted as falling within the scope of the present invention.

[0073] <Explanation of symbols>

[0074] 1: Thermoplastic polymer filament

[0075] 10: Raw material supply section 110: Filament feeder

[0076] 120: Cooling section 130: Heat insulation pipe section

[0077] 30: Radiating section 310: Nozzle

[0078] 320: Induction heating unit 330: Power control unit 340: Tilting unit

[0079] 50: Collector's Department

[0080] 70: Control unit 710: Feeder control module

[0081] 720: Heating control module 730: Voltage control module

Claims

1. Raw material supply section where thermoplastic polymer raw materials are fed; A radiation unit that melts the raw material supplied from the above raw material supply unit and radiates it through a nozzle; A collector section for collecting nanofibers radiated through a nozzle; and A control unit for controlling the melting electrospinning process; The above thermoplastic polymer raw material is a thermoplastic polymer filament that is filamentized in a customized manner according to the diameter of the nozzle and supplied long and continuously. The above raw material supply unit includes a filament feeder that precisely controls the supply speed or supply amount of a thermoplastic polymer filament that is filamentized and supplied long and continuously. A melt electrospinning nanofiber manufacturing device characterized in that the above-mentioned radiation unit includes an induction heating unit that melts a thermoplastic polymer filament supplied directly to the nozzle inlet using a non-contact induction heating method, and a power control unit that applies voltage between the nozzle and the collector unit.

2. In paragraph 1, The above control unit includes a feeder control module that controls the supply speed or supply amount of the thermoplastic polymer filament supplied through the filament feeder, a heating control module that controls the melting temperature of the thermoplastic polymer filament in the nozzle through control of the induction heating unit, and a voltage control module that controls the voltage between the nozzle and the collector unit through the power control unit. The above feeder control module controls the supply speed of the thermoplastic polymer filament within the range of 0.001 to 0.01 cc / m. The above heating control module controls the nozzle temperature within the range of 220 to 380 ℃. A melt electrospinning nanofiber manufacturing device characterized in that the voltage control module controls the voltage between the nozzle and the collector within a range of 18 to 100 kV.

3. In paragraph 1, The above thermoplastic polymer filament is a medical-use biodegradable thermoplastic polymer filament, and is a melt electrospinning nanofiber manufacturing device characterized in that it includes at least one from the group consisting of polyethylene oxide (PDO), polylactide (PLA), polyglycolide (PGA), and polycaprolactone (PCL).

4. In paragraph 1, The above thermoplastic polymer filament is an industrial thermoplastic polymer filament, and comprises at least one selected from the group 2-1 consisting of polyurethane, polyvinylidene fluoride, polyacetal, polyester, polycarbonate, polysulfone, polyetherimide, polyamideimide, polyphenylene sulfonate, polystyrene, polypropylene, vinyl chloride, vinyl acetate, polyvinyl alcohol, and polyamide, and ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, acrylonitrile-butadiene styrene copolymer, acrylonitrile-styrene copolymer, vinyl chloride vinyl chloride acetate copolymer, vinyl acetate maleate copolymer, vinyl chloride vinyl acetate copolymer, vinyl chloride vinylidene chloride copolymer, vinyl chloride acrylonitrile copolymer, ethylene vinyl chloride copolymer, propylene vinyl chloride. A melt electrospinning nanofiber manufacturing device characterized by comprising at least one group 2-2 composed of a copolymer.

5. In paragraph 3 or 4, The above thermoplastic polymer filament contains a melt functional additive, A melt electrospinning nanofiber manufacturing device characterized in that the above melt functional additive comprises at least one from group 3-1 consisting of polydimethylsiloxane (PDMS) and polyethylene glycol (PEG), at least one from group 3-2 consisting of stearic acid (SA), oleic acid (OA), citric acid (CA), propionic acid (PA), and gallic acid (GA), and at least one from group 3-3 consisting of alizarin, quercetin, chitosan, and epicatechin.

6. In paragraph 5, The above raw material supply unit is formed with cooling fins including a separate fan between the filament feeder and the induction heating unit to rapidly cool the heat generated in the induction heating unit and directed to the raw material supply unit, and a heat insulation conduit unit formed on the inside of the conduit above the induction heating unit in the conduit that supplies the thermoplastic polymer filament to the nozzle inlet to prevent the heat generated in the induction heating unit from being transferred to the raw material supply unit through the conduit. A melt electrospinning nanofiber manufacturing device characterized in that it further includes:

7. In paragraph 6, The above heat-insulating pipe section comprises 100 parts by weight of a metal oxide mixed with aluminum-doped zinc oxide and tungsten oxide selected from barium tungsten oxide, lithium tungsten oxide, and cesium tungsten oxide, 5 to 10 parts by weight of a first functional additive for preventing shrinkage even when there is a rapid change in temperature, and 5 to 10 parts by weight of a second functional additive for enhancing chemical resistance. The first functional additive comprises 80 to 95 parts by weight of sodium metasilicate, 5 to 10 parts by weight of sodium gluconate, and 1 to 5 parts by weight of a thickener. A melt electrospinning nanofiber manufacturing device, characterized in that the second functional additive comprises 1 to 5 parts by weight of a silane compound, 1 to 5 parts by weight of calcium nitrate, 1 to 5 parts by weight of nanoceramic particles, 1 to 5 parts by weight of graphene, and 1 to 5 parts by weight of mica.

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