Method for manufacturing nanofiber filter by using electrospinning and nanofiber filter manufactured by same manufacturing method

Abstract

The present invention relates to a method of manufacturing a nanofiber filter by using electrospinning and a nanofiber filter manufactured by the manufacturing method, wherein an electrospinning method is used to manufacture the nanofiber filter, so that the filter can be easily and simply manufactured, and moreover the distribution ratio of diameters of nanofibers can be uniformly adjusted, so as to solve the problem of efficiency deterioration when used as a filter. Further, by the present invention, the average diameter of the nanofibers can be adjusted by adjusting the injection speed, voltage conditions, and pressure conditions for the injected gas injected through a nozzle, so that the nanofiber filter can be manufactured to be suitable for the purpose and environment of use of the filter.

Description

Method for manufacturing a nanofiber filter using electrospinning and a nanofiber filter manufactured by the same

[0001] The present invention relates to a method for manufacturing a nanofiber filter using electrospinning and a nanofiber filter manufactured by the same.

[0002] The scientific basis of the electrospinning method for the production of nanofibers has been developed since 1882, when Raleigh calculated that electrostatic force could overcome surface tension during the falling of a liquid.

[0003] Electrospinning is known as a technology in which a polymer solution or polymer melt is stretched to have a cross-sectional area of ​​tens to hundreds of nanometers as it moves through a nozzle of a reservoir to a grounded integrated plate by electrostatic force generated by a high voltage of several kV or more.

[0004] In other words, when an externally applied electric field exceeds a specific threshold, the charge generated on the surface of the polymer solution extruded from the nozzle becomes greater than the surface tension of the polymer solution, thereby generating a liquid jet. The resulting microfiber is then stretched into ultrafine fibers through electrically generated bending instability. This process allows for the control of fiber thickness by varying the magnitude of the electric field and the concentration of the polymer solution.

[0005] Fibers produced by the electrospinning method exhibit entirely new characteristics when their diameter is reduced from micrometers to nanometers, such as an increase in the surface area-to-volume ratio, improved surface functionality, and enhanced mechanical properties including tensile strength.

[0006] Nanofibers produced in this manner have a wide range of applications, including filter materials (EP1483034, US6,875,256), photochemical sensor materials, carbon materials such as carbon nanotubes (US2005 / 0025974, EP1500677), biomedical materials (US4,043,331, US4,878,908, WO 05 / 039664, WO 05 / 037339), tissue engineering materials (WO 05 / 026530, WO 05 / 047493), drug delivery materials (WO 04 / 014304), basic materials for DNA manufacturing, and cosmetic materials (WO 01 / 026610).

[0007] The aforementioned electrospinning method has recently gained popularity due to its advantage of allowing for the easy and simple manufacture of filters. However, when nanofibers are manufactured using the electrospinning method for use as filter materials, there is a problem where filter efficiency is reduced because the distribution ratio of the nanofiber diameters is not uniform.

[0008] It is necessary to develop a method for manufacturing nanofiber filters that utilizes the advantages of electrospinning to resolve these issues.

[0009] [Prior Art Literature]

[0010] [Patent Literature]

[0011] KR 10-1650355 B1

[0012] The object of the present invention is to provide a method for manufacturing a nanofiber filter using electrospinning and a nanofiber filter manufactured by the same.

[0013] Another objective of the present invention is to provide a method for manufacturing nanofibers using an electrospinning method, which not only allows for easy and simple production of the filter but also improves the problem of reduced efficiency when used as a filter by uniformly controlling the distribution ratio of the diameters.

[0014] Another objective of the present invention is to provide a method for manufacturing nanofibers suitable for the purpose and environment of use of a filter by controlling the average diameter of the nanofibers by adjusting the injection speed, voltage conditions, and pressure conditions of the injected gas sprayed through a nozzle, and to provide a nanofiber filter comprising nanofibers manufactured by said method.

[0015] To achieve the above-mentioned objective, the present invention may relate to a method for manufacturing a nanofiber filter using electrospinning, comprising the steps of: dissolving a polymer compound in a solvent to prepare a spinning solution for electrospinning; injecting the spinning solution into an electrospinning device and electrospinning to form a nanofiber web; and drying the nanofiber web with hot air, wherein the electrospinning is carried out under conditions in which the temperature is 20°C to 32°C, the humidity is 10% to 60%, the voltage is 40 kV to 60 kV, and the spinning solution spray speed is 0.1 m / min to 2.0 m / min to form a nanofiber web.

[0016] In addition, the above spinning solution can be electrospun onto one surface of a support to form a nanofiber web.

[0017] In addition, the electrospinning uses an electrospinning nozzle in a nozzle pack, the electrospinning nozzle has a gauge of 18 to 31 gauge, and the nozzle pack may include 150 to 250 electrospinning nozzles.

[0018] In addition, the above electrospinning can be carried out simultaneously with air injection by a gas injection nozzle located on the outer circumference of the electrospinning nozzle.

[0019] In addition, the above air injection is 0.1 kg / cm² 2 up to 2 kg / cm² 2 It can proceed under the injection pressure conditions of.

[0020] In addition, the spinning solution may contain a polymer compound in an amount of 10% to 30% by weight.

[0021] In addition, the above-mentioned spinning solution may include a high-boiling point solvent and a low-boiling point solvent.

[0022]

[0023] In addition, the high boiling point solution may be selected from the group consisting of DMAc (N,N-Dimethylacetoamide), DMSO (Dimethyl Sulfoxide), NMP (N-Methyl-2-pyrrolidone), DMF (Dimethylformamide), Benzyl Alcohol, and mixtures thereof.

[0024] In addition, the low boiling point solvent may be selected from the group consisting of acetone, THF (Tetrahydrofuran), ethyl acetate, DCM (Dichloromethane), and mixtures thereof.

[0025] Another invention for achieving the above-described purpose may be a nanofiber filter manufactured by the above-described manufacturing method.

[0026] The present invention manufactures a nanofiber filter using an electrospinning method, which not only allows for easy and simple production of the filter but also improves the problem of reduced efficiency when used as a filter by uniformly controlling the distribution ratio of the diameter.

[0027] In addition, the average diameter of the nanofibers can be controlled by adjusting the injection speed, voltage conditions, and injection gas pressure conditions through the nozzle, allowing the filter to be manufactured to suit its intended purpose and operating environment.

[0028] Figure 1 is an SEM image of a nanofiber according to one embodiment of the present invention.

[0029] Figure 2 is an SEM image of a nanofiber according to one embodiment of the present invention.

[0030] Figure 3 is an SEM image of a nanofiber according to one embodiment of the present invention.

[0031] FIG. 4 is an enlarged view of a hinge system according to the present invention.

[0032] FIG. 5 is a block diagram of the main components of an electrospinning device according to the present invention.

[0033] FIG. 6 illustrates an example in which a plurality of mixer parts and a plurality of nozzles are formed according to the present invention.

[0034] The present invention relates to a method for manufacturing a nanofiber filter using electrospinning, comprising the steps of: preparing a spinning solution for electrospinning by dissolving a polymer compound in a solvent; injecting the spinning solution into an electrospinning device and electrospinning to form a nanofiber web; and drying the nanofiber web with hot air, wherein the electrospinning is carried out under conditions in which the temperature is 20°C to 32°C, the humidity is 10% to 60%, the voltage is 40 kV to 60 kV, and the spinning solution spray speed is 0.1 m / min to 2.0 m / min to form a nanofiber web.

[0035] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0036] With the advancement of industry and the increasing awareness of environmental issues such as air pollution, there is a demand for the development of air purification devices capable of efficiently separating and removing polluted air.

[0037] These devices primarily utilize filters capable of separating contaminants and discharging filtered clean air. Such filters generally contain one or more web-shaped nanofibers along with a substrate material within the filter structure. The nanofibers are fibers with a diameter of several hundred nanometers (nm) or less, referring to a new concept of fiber material that possesses functions and performance different from conventional fiber materials.

[0038] Furthermore, since nanofibers contain multiple pores, nanofiber filters containing such nanofibers can separate particles larger than tens of nano-sized particles and possess excellent filtration capabilities and high particle capture capabilities, allowing them to effectively filter out a large amount of fine particles from the air in a short period of time.

[0039] However, conventional nanofiber filters used for air purification had a problem in that their separation efficiency significantly decreased and their ability to filter fine dust was reduced as the surface of the filter became contaminated by the fine dust to be separated during prolonged use.

[0040] Recently, development is underway to manufacture filters with various functions, including separation performance, by incorporating functional materials into nanofibers. To produce these functional nanofibers, a method is primarily used in which a mixture of nanofiber constituent materials and functional materials is added to form web-shaped nanofibers.

[0041] However, nanofibers manufactured by this method have the disadvantage that it is difficult to uniformly disperse functional materials on the surface, and the functional materials mixed into the nanofiber constituent materials affect the pore size of the nanofiber filter, thereby degrading the filter's performance.

[0042] Various manufacturing methods have been proposed to produce the above-mentioned nanofibers, and one of them is a method using electrospinning.

[0043] Electrospinning is a method for producing thread-like fibers with diameters ranging from several nanometers (nm) to several micrometers (µm) by spraying a dissolved polymer solution within an electric field. The production of these continuous fibers is simpler and less restricted in materials compared to various previously known fabrication methods (such as mold synthesis, self-assembly, and phase separation). This electrospinning method can be applied to a wide range of polymer compounds and is suitable for various applications.

[0044] However, manufacturing nanofibers by the aforementioned electrospinning method makes it difficult to produce nanofibers with a uniform diameter, and improvements are needed for mass production for commercialization beyond the laboratory scale.

[0045] The present invention is characterized by using an electrospinning method to manufacture a nanofiber filter that can be used as an air filter. The nanofiber filter manufactured by the manufacturing method of the present invention can provide a method that not only has no large variation in the diameters of a plurality of nanofibers, but also has a nanofiber diameter of up to about 50 nm, and can be manufactured such that there is no large variation between the minimum diameter and the maximum diameter among the nanofiber diameters.

[0046] The manufacturing method of the present invention described above is based on the use of the electrospinning device described below, and may be significantly affected not only by the electrospinning device of the present invention but also by the spinning solution, conditions during electrospinning, etc.

[0047] That is, in order to manufacture nanofibers having a uniform diameter as in the present invention and utilize them as nanofiber filters, it is possible to implement this by using the electrospinning device described above and simultaneously following the method for manufacturing nanofiber filters using electrospinning of the present invention.

[0048] Specifically, the present invention relates to a method for manufacturing a nanofiber filter using electrospinning, comprising the steps of: preparing a spinning solution for electrospinning by dissolving a polymer compound in a solvent; injecting the spinning solution into an electrospinning device and electrospinning to form a nanofiber web; and drying the nanofiber web with hot air, wherein the electrospinning is carried out under conditions in which the temperature is 20°C to 32°C, the humidity is 10% to 60%, the voltage is 40 kV to 60 kV, and the spinning solution spray speed is 0.1 m / min to 2.0 m / min to form a nanofiber web.

[0049] The above spinning solution can be electrospun onto one side of a support to form a nanofiber web.

[0050] The present invention relates to manufacturing a nanofiber filter using an electrospinning method, wherein a nanofiber web manufactured by the electrospinning method described above can be formed on one surface of a support.

[0051] The above support may be a nonwoven fabric, imitation paper, etc. For example, any one of a melt-blown nonwoven fabric, a spun bond nonwoven fabric, a thermal bond nonwoven fabric, a chemical bond nonwoven fabric, or a wet-laid nonwoven fabric may be used as the support, but is not limited to the above examples, and any nonwoven fabric that can be used to manufacture the nanofiber filter of the present invention may be used without limitation.

[0052] The above polymer compounds may include hydrophilic polymers and hydrophobic polymers, and one or more of these polymers may be used in combination.

[0053] The polymer compounds usable in the present invention are not particularly limited as long as they are resins that can be dissolved in an organic solvent for electrospinning and can form nanofibers by electrospinning. Examples include polyvinylidene fluoride (PVdF), poly(vinylidene fluoride-co-hexafluoropropylene), perfluoropolymer, polyvinyl chloride, polyvinylidene chloride or copolymers thereof, polyethylene glycol derivatives including polyethylene glycol dialkyl ether and polyethylene glycol dialkyl ester, poly(oxymethylene-oligo-oxyethylene), polyoxide including polyethylene oxide and polypropylene oxide, polyvinyl acetate, poly(vinylpyrrolidone-vinyl acetate), polystyrene and polystyrene acrylonitrile copolymer, polyacrylonitrile (PAN), polyacrylonitrile copolymer including polyacrylonitrile methyl methacrylate copolymer, polymethyl methacrylate, polymethyl methacrylate copolymer or mixtures thereof.

[0054] In addition, examples of usable polymer compounds include aromatic polyesters such as polyamide, polyimide, polyamideimide, poly(meta-phenylene isophthalamide), polysulfone, polyetherketone, polyetherimide, polyethylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polytetrafluoroethylene, polydiphenoxyphosphazene, and poly{bis[2-(2-methoxyethoxy)phosphazene]}, polyurethane copolymers including polyurethane and polyetherurethane, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, etc.

[0055] Among the above polymer compounds, PAN, polyvinylidene fluoride (PVdF), polyester sulfone (PES), and polystyrene (PS) are particularly preferred as nanofiber filter materials of the present invention, or polyvinylidene fluoride (PVdF) and polyacrylonitrile (PAN) are mixed, or PVdF and PES, or PVdF and thermoplastic polyurethane (TPU) are mixed, but are not limited to the above examples, and any polymer compound that can be used as a nanofiber filter, more specifically as an air filter, can be used without limitation.

[0056] To manufacture the nanofiber filter of the present invention, the first step is to dissolve the aforementioned polymer compound in a solvent to prepare a spinning solution for electrospinning.

[0057] The above spinning solution may contain a polymer compound in an amount of 10% to 30% by weight, preferably 12% to 28% by weight, 15% to 25% by weight, 15% to 24% by weight, 15% to 23% by weight, 15% to 22% by weight, 15% to 21% by weight, and 15% to 20% by weight. If the amount is less than the range described above, it may not be easy to form fibers by the electrospinning method, or spinning may not occur and instead result in spraying, forming particles rather than fibers, or even if spinning occurs, many beads may be formed, and the solvent may not volatilize well, causing the filter material to melt and clog the pores during the web calendering process. Furthermore, as described below, the present invention is characterized by manufacturing nanofibers having a uniform diameter, but manufacturing nanofibers having a uniform diameter is not easy. In addition, if the content of the polymer compound exceeds the aforementioned range, the viscosity increases, causing solidification at the surface of the solution, making long-term spinning difficult, and there is a problem that the fiber diameter increases, making it difficult to produce nanofibers having a uniform diameter range.

[0058] The above spinning solution may include a high-boiling point solvent and a low-boiling point solvent. That is, the spinning solution of the present invention may be prepared by mixing a polymer compound with a mixed solvent containing the aforementioned high-boiling point solvent and low-boiling point solvent. In the mixed solution obtained by mixing the high-boiling point solvent and the low-boiling point solvent as described above, under conditions such as a specific temperature range, humidity range, air injection pressure range, voltage conditions, and nozzle injection conditions, the volatilization times of the low-boiling point solvent and the high-boiling point solvent differ, and due to the appropriate evaporation of the solvent, it becomes possible to produce nanofibers having a uniform diameter range.

[0059] In other words, the method for manufacturing a nanofiber filter according to the present invention enables the production of nanofibers having a uniform diameter by sequentially evaporating high-boiling-point solvents and low-boiling-point solvents contained in the spinning solution under conditions such as the concentration of the spinning solution, temperature range, humidity range, air injection pressure range, voltage conditions, and nozzle injection speed conditions, regardless of the type of polymer compound. That is, when only one type of solvent is included, when manufacturing fibers by electrospinning, even if the aforementioned conditions are finely adjusted, spinning cannot occur, making it almost impossible to form a nanofiber web; or, instead of spinning, spraying occurs, forming particles rather than fibers; or even if spinning occurs, many beads are formed; and because the solvent does not volatilize well, partial melting occurs during the web lamination process, causing pore blockage. Furthermore, the solvent volatilizes very rapidly, causing nozzle blockage and acting as a cause of spinning trouble.

[0060] The above high boiling point solution may be selected from the group consisting of DMAc (N,N-Dimethylacetoamide), DMSO (Dimethyl Sulfoxide), NMP (N-Methyl-2-pyrrolidone), DMF (Dimethylformamide), Benzyl Alcohol, and mixtures thereof.

[0061] The above low-boiling point solvent may be selected from the group consisting of acetone, THF (Tetrahydrofuran), ethyl acetate, DCM (Dichloromethane), and mixtures thereof.

[0062] The mixed solution for preparing the spinning solution of the present invention may preferably include DMAc (boiling point 165°C), DMSO (boiling point 189°C), and ethyl acetate (boiling point 77.1°C), and more preferably may include DMAc, DMSO, and ethyl acetate in a weight ratio of 3:5:2 to 3:6:1. The mixed solution is characterized by including three types of solvents as described above. When the spinning solution is prepared by combining the three types of solvents as DMAc and ethyl acetate, or as DMSO and ethyl acetate in a ratio of 8:2 or 9:1, it is not easy to produce nanofibers having a uniform diameter.

[0063] The spinning solution prepared as described above can be injected into an electrospinning device and electrospun to form a nanofiber web. At this time, the electrospinning can be carried out under conditions where the temperature is 20°C to 32°C, the humidity is 10% to 60%, the voltage is 40 kV to 60 kV, and the spinning solution injection speed is 0.1 m / min to 2.0 m / min to form a nanofiber web.

[0064] When a nanofiber web is formed by the electrospinning method of the present invention under the above conditions of temperature, humidity, voltage, and the injection speed of the spinning solution, it becomes possible to manufacture nanofibers having a uniform diameter by the electrospinning device described below.

[0065] The manufacture of the above-mentioned nanofibers having a uniform diameter can increase the efficiency of impurity removal when applied as an air filter, and thus is directly related to filter performance. That is, the nanofiber web consists of nanofibers intertwined in a complex shape, is ultra-lightweight, has a large specific surface area, and possesses high porosity.

[0066] The electrospinning device of the present invention includes a nozzle pack, and the nozzle pack includes a plurality of electrospinning nozzles. The electrospinning nozzles are located in the nozzle pack in a manner such as 150 to 250, 150 to 240, 150 to 230, 150 to 220, and 150 to 210. As described above, when a plurality of electrospinning nozzles are located within a single nozzle pack and nanofibers are formed simultaneously through electrospinning at the electrospinning nozzles, nanofibers having a uniform diameter become complexly entangled, thereby forming a three-dimensional network structure. That is, the nanofibers produced through the plurality of electrospinning nozzles are laminated on one surface of a support, and when nanofibers are continuously formed at 150 to 250 electrospinning nozzles, they become entangled with each other to form a web. At this time, if the diameter of the nanofibers is not uniform, the pores formed by the entanglement phenomenon between multiple nanofibers become relatively smaller, and the specific surface area also becomes relatively smaller.

[0067] In addition, the above-mentioned spinning nozzle may have a gauge of 18 to 31 gauge, 18 to 30 gauge, 18 to 29 gauge, 18 to 28 gauge, 18 to 27 gauge, 18 to 26 gauge, 18 to 25 gauge, 19 to 25 gauge, and 20 to 25 gauge. Not only can it be manufactured into nanofibers having a uniform diameter within the above range, but as described below, it can also be manufactured into nanofiber filters that exhibit excellent filtration performance as air filters.

[0068] As mentioned above, if the pores and specific surface area of ​​the nanofiber web become smaller, it will be directly linked to a reduction in the filtration area when applied as a filter.

[0069] In other words, to further improve the filtration performance of the air filter, it is necessary to expand the filtration surface area of ​​the nanofiber web, and for this, a large specific surface area and high porosity are required.

[0070] To this end, the present invention requires the fabrication of a nanofiber filter having a constant diameter, and more specifically, the average diameter of the nanofiber is 100 nm to 300 nm, more specifically, the average diameter is 200 nm to 300 nm, 200 nm to 290 nm, 200 nm to 280 nm, 200 nm to 270 nm, 200 nm to 260 nm, and 200 nm to 250 nm. In addition, the average diameter may be 100 nm to 190 nm, 100 nm to 180 nm, 100 nm to 170 nm, 100 nm to 160 nm, 100 nm to 150 nm, 100 nm to 140 nm, 100 nm to 130 nm, 100 nm to 120 nm, and 100 nm to 110 nm. As described above, the range of the average diameter of the nanofibers produced by the electrospinning method of the present invention can be controlled by adjusting the manufacturing conditions, particularly by controlling the temperature, humidity, and the spraying speed of the spinning solution. As described above, the average diameter of the nanofibers can be produced to be 200 nm to 300 nm or 100 nm to 200 nm.

[0071] When the average diameter of the nanofiber is 200 nm to 300 nm, the minimum diameter may be 150 nm to 180 nm and 160 nm to 170 nm, and the maximum diameter may be 290 nm to 320 nm and 300 nm to 310 nm. The difference between the maximum and minimum diameters is not large compared to the average value.

[0072] In addition, when the average diameter of the nanofiber is 100 nm to 190 nm, the minimum diameter may be 40 nm to 60 nm and 45 nm to 55 nm, and the maximum diameter may be 170 nm to 190 nm and 175 nm to 185 nm. The difference between the maximum and minimum diameters is not large compared to the average value.

[0073] The electrospinning device of the present invention is characterized by including a plurality of electrospinning nozzles within a nozzle pack as described above. Typically, a nozzle pack includes a high-pressure electrode tube and a gas injection tube for providing compressed air. However, in the present invention, as described below, the electrode tube and the gas injection tube are located separately outside the nozzle pack, so that 200 to 300 electrospinning nozzles are located within the nozzle pack as described above. As a result of having many electrospinning nozzles within the nozzle pack as described above, the spacing between the electrospinning nozzles becomes very close. This not only enables the manufacturing of a nanofiber web with a large specific surface area and high porosity, but also provides characteristics that are very easy to mass-produce compared to existing manufacturing facilities.

[0074] When electrospinning by the above gas injection pipe, the injected air jet is 0.1 kg / cm² 2 up to 2 kg / cm² 2 It proceeds under injection pressure conditions of 0.11 kg / cm² 2 Up to 1.9 kg / cm² 2 It proceeds under injection pressure conditions of 0.12 kg / cm² 2 Up to 1.8 kg / cm² 2 It proceeds under injection pressure conditions of 0.13 kg / cm² 2 Up to 1.7 kg / cm² 2 It proceeds under injection pressure conditions of 0.14 kg / cm² 2 Up to 1.6 kg / cm² 2 It proceeds under injection pressure conditions of 0.15 kg / cm² 2up to 1.5 kg / cm² 2 It proceeds under injection pressure conditions of 0.16 kg / cm² 2 Up to 1.4 kg / cm² 2 It proceeds under injection pressure conditions of 0.17 kg / cm² 2 Up to 1.3 kg / cm² 2 It proceeds under injection pressure conditions of 0.18 kg / cm² 2 Up to 1.2 kg / cm² 2 It proceeds under injection pressure conditions of 0.19 kg / cm² 2 Up to 1.1 kg / cm² 2 It proceeds under injection pressure conditions of 0.2 kg / cm² 2 Up to 1.1 kg / cm² 2 It can proceed under the injection pressure conditions of.

[0075] In the process of manufacturing nanofibers by electrospinning, when a high voltage is applied, the polymer forms a hemispherical shape at the tip of the nozzle due to surface tension, and then changes into a Taylor cone shape due to mutual electrostatic repulsion between surface charges and an external electric field. When an electric field of a specific strength is applied, one charge accumulates and is spun due to the repulsion, causing the fibers to gather in the direction of a collector that is charged with the opposite charge or grounded. During spinning, the liquid solvent sprayed evaporates, causing the fibers to be arranged randomly at the collector. At this time, to more efficiently volatilize the liquid solvent and control the shape of the nanofibers, air spraying may be performed under the aforementioned spraying pressure conditions.

[0076] When air injection is performed under injection pressure conditions within the aforementioned range, sequential volatilization of the mixed solution within the spinning solution occurs, thereby enabling the formation of nanofibers with a uniform diameter.

[0077] An electrospinning apparatus for manufacturing a nanofiber filter by the electrospinning method of the present invention. FIG. 4 illustrates the configuration of an electrospinning apparatus according to the present invention. FIG. 5 illustrates a block diagram of the main configuration of an electrospinning apparatus according to the present invention. Hereinafter, the configuration and effects of an electrospinning apparatus according to the present invention will be explained with reference to FIG. 4 and FIG. 5.

[0078] The electrospinning device according to the present invention includes a high voltage supply unit (100), a spinning solution supply unit (200), a mixer unit (300), an air supply unit (500), a nozzle pack unit (600), a drying unit (700), and a collector unit (800).

[0079] The high-voltage supply unit (100) includes a high-voltage generator (110) and a high-voltage distributor (120). The high-voltage generator is an essential component of the electrospinning device and generates high voltage to impart an electric charge to the fiber raw material solution. The high-voltage generator (110) is a device that converts an input voltage (AC or DC) into a high voltage of tens of kV by high-frequency conversion and transformer-based step-up. Internally, it includes a high-voltage transformer, a rectifier, and a filter circuit to ensure a stable high-voltage output.

[0080] The high-voltage distributor (120) serves to distribute the voltage generated from the high-voltage generator (110) to the mixer section (300) within the electrospinning device.

[0081] The spinning solution supply unit (200) includes a tank (210), a pump (220), and a solution distributor (230). A solution in which a fiber raw material is dissolved is stored in the tank (210), and the solution is transferred to the solution distributor (230) via the pump (220). The spinning solution distributor (230) is connected to the mixer unit (300) and serves to distribute the solution to the mixer unit (300). The amount of distribution can be adjusted, and since this is a known function of a distributor, a detailed description will be omitted.

[0082] The mixer unit (300) consists of a main body (310) and an electrode (320). The main body (310) is in the shape of a tube, through which a solution in which fiber raw material is dissolved from a solution distributor (230) passes. The main body (310) is designed in a cylindrical or tube shape to stably maintain the flow of the solution passing through its interior. A flow path design (e.g., straight flow type, vortex suppression type) may be applied to the interior of the main body (310) to optimize the flow of the solution. The main body (310) maintains the fiber raw material solution supplied from the solution distributor (230) uniformly and transmits the charged solution through the electrode (320) to the nozzle pack unit (600).

[0083] The electrode (320) is installed inside or outside the main body (310) and is electrically connected to the high-voltage distributor (120). The shape of the electrode (320) can be designed as a rod, ring, or mesh type to optimize the application of charge to the solution. The high voltage received from the high-voltage distributor (120) is applied to the solution to make it charge.

[0084] The mixer unit (300) may additionally perform a mixing function to maintain the uniformity of the concentration, viscosity, or charge state of the fiber raw material solution. It may be designed so that the solution is naturally mixed by installing a spiral channel or a porous obstacle inside the main body, or the solution may be mechanically mixed by installing a rotary blade or screw inside the main body. In addition,

[0085] An ultrasonic generator can be used to support fine mixing and degassing (bubble removal) of the solution.

[0086] The air supply unit (500) includes a compressor (510) and an air nozzle (520). The air nozzle (520) is directed toward the vicinity of the nozzle (620) of the nozzle pack unit (600) and sprays high-pressure air generated from the compressor (510). The air supply unit (500) performs an important function in controlling and stabilizing the airflow during the process of fiber formation through the nozzle pack unit (600). The extruded solution moves to the collector unit (800) by an electric field, and at this time, the air supply unit (500) controls the airflow to stabilize the trajectory and shape of the extruded fiber. In addition, the appropriate airflow maintains a uniform elongation speed of the fiber, thereby maintaining the diameter and quality of the extruded fiber at a constant level.

[0087] Additionally, the air supply unit (500) serves to remove vapors of volatile solvents. Fiber raw material solutions often contain volatile solvents such as acetone and ethanol. The air supply unit (500) inhales or expels solvent vapors generated around the nozzle to maintain a safe working environment.

[0088] In addition, it can prevent steam from accumulating inside the device, thereby increasing the safety of the radiation process and reducing the risk of fire.

[0089] Additionally, the air supply unit (500) absorbs or disperses heat generated during the radiation process, thereby lowering the temperature inside the device. In particular, it plays an important role in lowering the temperature around the nozzle pack unit (600).

[0090] In addition, appropriate cooling air is provided so that the spun fibers can solidify as they cool in the air.

[0091] Additionally, the air supply unit (500) induces the spun fibers to be oriented in a specific direction. By controlling the direction and speed of the airflow, it helps the fibers to be aligned in a desired shape on the collection surface.

[0092] The nozzle pack unit (600) includes a nozzle pack body (610) and a nozzle (620). The nozzle pack unit (600) is a core component of the electrospinning device and enables stable and uniform spinning by working in conjunction with the high-voltage supply unit (100) and the solution supply unit (200).

[0093] The nozzle pack body (610) is designed to support and fix multiple nozzles and is made of a modular frame. For example, a distribution channel may be formed inside to maintain a uniform flow of the solution.

[0094] The nozzle (620) is generally made of stainless steel or a highly corrosion-resistant metal to maintain durability and precision. Multiple nozzles (620) may be formed. At this time, multiple mixer sections (300) and nozzles (620) may be formed, and the designer may pre-design and determine the number of nozzles (620) to optimize the distribution of the solution. FIG. 6 illustrates an example in which multiple mixer sections (300) and multiple nozzles (620) are formed.

[0095] In addition, the nozzle (620) of the present invention is characterized by having a plurality of nozzles compared to a conventional electrospinning device. That is, it is characterized by including a plurality of nozzles (620) compared to a conventional electrospinning device. This is because, in the electrospinning device of the present invention, the high-voltage supply unit (100) and the air supply unit (500) are located outside the nozzle pack unit (600), allowing the nozzles (620) within the nozzle pack unit (600) to be positioned more densely. Through this, the nozzle pack unit (600) can be simplified, and cleaning and maintenance of the nozzle pack unit (600) are easier. In addition, the electrospinning device of the present invention can position 150 to 250, 150 to 240, 150 to 230, 150 to 220, or 150 to 210 nozzles (620) within the nozzle pack (600), making it easier to mass-produce compared to conventional electrospinning devices.

[0096] The nozzle (620) may have a distance (TCD) from the collection collector (800) of 110 mm to 150 mm, 115 mm to 150 mm, 115 mm to 145 mm, or 115 mm to 140 mm. By the above TCD, the length, diameter, alignment direction, etc. of the nanofiber can be controlled in the electrospinning process. In addition to the electrospinning conditions described above, by adjusting the TCD range, not only can the average diameter of the nanofiber be controlled, but when manufacturing nanofibers within the above range, dust collection performance can be improved, pressure loss can be achieved, and the Q-Factor value, which is a variable indicating the performance of the filter, is excellent.

[0097] The drying unit (700) is composed of a hot air drying device for completely removing volatile solvents contained in the solution and stably solidifying the spun fibers during the process in which the solution spun from the electrospinning device moves to the collection collector unit (800). The drying unit (800) plays a key role in improving the quality of the fibers and enhancing the safety of the working environment against solvent vapors.

[0098] The drying unit (700) may include a hot air generator, an air circulation device, and a control panel. The hot air generator is composed of a heater for generating high-temperature air and generally includes an electric heater coil or a gas heater. A temperature sensor and a PID controller are built in to maintain a uniform temperature of the air. For example, the air can be heated to an appropriate temperature (e.g., 40 to 120°C) required for the fiber to solidify.

[0099] The air circulation device is equipped with a fan or a blower to deliver hot air to the collector section (800). It may include a damper and an air velocity sensor to control the airflow. By distributing the hot air evenly, it acts evenly on the surface of the fibers, and by controlling the speed and direction of the airflow, it can improve the solidification and collection stability of the fibers.

[0100] The control panel is a control device that allows for real-time adjustment of hot air temperature, airflow speed, and other parameters. Temperature and airflow status can be monitored through a digital display.

[0101] The collector section (800) is an area where fibers spun from an electrospinning device are collected, and it serves to maintain the shape of the fibers and ensure they are uniformly arranged. The collector section (800) is composed of a roller (810) and a belt (820) and is characterized by the application of a negative voltage to form a potential difference with the high voltage applied to the solution.

[0102] The roller (810) has a cylindrical structure and is mainly made of a highly durable metal material such as stainless steel or aluminum. The surface of the roller (810) is coated with an anti-static coating or a smooth surface treatment to increase the efficiency of fiber collection. Additionally, it supports and rotates the belt (820) to collect fibers evenly. It supports the uniform distribution of fibers and can adjust the rotation speed as needed.

[0103] The belt (820) has an infinite loop structure driven by a roller (810), and the surface of the belt is treated with a special coating to ensure good adhesion of fibers. It continuously collects fibers to maximize production efficiency and moves at a constant speed to evenly distribute the spun fibers. After collecting the fibers, the collected fibers are transferred to the next process (e.g., drying, packaging).

[0104] A negative voltage is applied to the collector (800) to create a potential difference with the radiated solution. Generally, a voltage between -5 kV and -30 kV is used to create an electric field that allows the radiated solution to move stably to the collector (800).

[0105]

[0106] Preparation Example

[0107] Polyethersulfone (PES) was dissolved in a mixed solution of DMAc, DMSO, and ethyl acetate in the proportions shown in Table 1 below to prepare a spinning solution containing 15 wt% of PES.

[0108] The above spinning solution is injected into the electrospinning device described above, at 31°C to 33°C, humidity 50%, spinning solution spray speed 0.2 m / min, voltage 40 to 60 Kv, and 0.5 kg / cm² 2 Electrospinning was carried out under air injection conditions. A melt-blown nonwoven fabric was used as a support, and a nanofiber web was formed by electrospinning on one surface of the support. The electrospinning pack of the electrospinning device used included six 25 gauge (G) electrospinning nozzles.

[0109] NS1NS2NS3NS4NS5NS6DMAc8-9-33DMSO-8-956ethyl acetate221121

[0110] (Weight ratio)

[0111] Experimental Example 1

[0112] Results of measuring the average diameter of nanofibers

[0113] A spinning solution was prepared using the mixed solvent of NS5 as described above, and a nanofiber web was formed under the manufacturing conditions described above. The results of measuring the average diameter of the nanofibers are shown in FIG. 1 and Table 2 below:

[0114] NODiameter(nm)12662234330241695188617272618157917610251Min169Max302Avg.228

[0115] According to the experimental results above, the average diameter of the nanofibers was measured to be 228 nm, the minimum diameter 169 nm, and the maximum diameter 302 nm. Nanofiber webs were prepared for NS1 to NS4 and NS6 using the same method, and the diameters of the nanofibers were measured; the results are shown in Table 3 below:

[0116] NODiameter(nm)NS1NS2NS3NS4NS61339201204555255225121020924221232342342422092884591247258271161526127627627217462863 32312312168721834920720024981995893323321469302298561415174Min199201204200168Max591589561555288Avg.298304289312203

[0117] According to the experimental results above, it was confirmed that NS6 has an average diameter of 203 nm, a minimum diameter of 168 nm, and a maximum diameter of 288 nm. On the other hand, for NS1 to NS4, the average diameters were 298 nm, 304 nm, 289 nm, and 312 nm, which is not a significant difference; however, the minimum diameters were 199 nm, 201 nm, 204 nm, and 200 nm, and the maximum diameters were 591 nm, 589 nm, 561 nm, and 555 nm, indicating a large disparity between the minimum and maximum diameters relative to the average diameter. A representative SEM image of NS1 is shown in Figure 2.

[0118] Experimental Example 2

[0119] Whether the average diameter of nanofibers can be controlled

[0120] The measurement results of the average diameter of nanofibers prepared under the same conditions as in Preparation Example 1 above, except that NS5 was used as the spinning solution and the spinning solution injection speed was adjusted to 0.3 m / min, are as shown in Table 4 and Figure 3 below:

[0121] NODiameter(nm)1141.94254.032353.7634125.397559.146159.2167146.055849.567955.3531051.00411162.095121 49.09113113.03114122.8351561.31680.64517180.24818109.65619166.9272061.3Min49.567Max180.248Avg.105.13

[0122] As the spinning solution spraying speed was adjusted among the above manufacturing conditions, the average diameter of the nanofiber was found to be 105 nm, the minimum diameter was 49.6 nm, and the maximum diameter was 180 nm. In other words, it was confirmed that the average diameter of the nanofiber can be controlled by adjusting the spinning solution spraying speed among the manufacturing conditions of the present invention.

[0123] Experimental Example 3

[0124] Performance evaluation of nanofiber filters according to changes in electrospinning conditions

[0125] A spinning solution was prepared using the mixed solvent of NS5 mentioned above, and nanofibers were produced under the following electrospinning conditions, after which filter performance was evaluated. Conditions not listed in Table 5 below were the same as those in the preparation example.

[0126] Case. Experimental Environment Electrospinning Conditions Raw Material Result Remarks High Temperature (°C) Humidity (%) High Voltage (kV) TCD (mm) Type Fraction Presence of Additives Average Wire Diameter [nm] Dust Collection Performance [%] Pressure Loss [mmH2O] QFactor Exp. 1 25±5 30~50 70 110 PES 20~25 X 29 8 Unevaluated Unevaluated Unevaluated - Exp. 2 25±5 30~50 60 120 PES 20~25 O 228 8 2.06 6.25 0.028 - Exp. 3 25±5 30~50 57 130 PES 20~25 O 105 9 4.27 17.49 0.016 - Exp. 4 25±5 30~50 60 130 PES 15~20 O 80 9 5.29 3.95 0.079 Fiber wire diameter <100nm realized

[0127] The performance evaluation of the above filter was conducted after antistatic treatment in accordance with ISO 29463-5 standards.

[0128] It was confirmed that the nanofibers of the present invention exhibit a performance index equivalent to or greater than that of existing commercially available air filters.

[0129] In particular, when the average diameter of the nanofiber was produced to be 100 nm or less, the Q-Factor value was 0.079, confirming that it exhibited excellent performance compared to existing nanofibers with a diameter of 200 nm to 300 nm.

[0130] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

[0131] The present invention relates to a method for manufacturing a nanofiber filter using electrospinning and a nanofiber filter manufactured by the same.

Claims

1. A step of preparing a spinning solution for electrospinning by dissolving a polymer compound in a solvent; The step of injecting the above spinning solution into an electrospinning device and electrospinning to form a nanofiber web; and The method includes the step of hot-air drying the above nanofiber web, The above electrospinning is carried out under conditions where the temperature is 20°C to 32°C, the humidity is 10% to 60%, the voltage is 40 kV to 60 kV, and the spinning solution jet velocity is 0.1 m / min to 2.0 m / min to form a nanofiber web. Method for manufacturing a nanofiber filter using electrospinning.

2. In Paragraph 1, The above spinning solution is electrospun onto one side of a support to form a nanofiber web. Method for manufacturing a nanofiber filter using electrospinning.

3. In Paragraph 1, The above electrospinning uses an electrospinning nozzle within a nozzle pack, and The above electrospinning nozzle has a gauge of 18 to 31 gauge, and The nozzle pack comprises 150 to 250 electrospinning nozzles. Method for manufacturing a nanofiber filter using electrospinning.

4. In Paragraph 3, The above electrospinning proceeds simultaneously with air injection by a gas injection nozzle located on the outer periphery of the electrospinning nozzle. Method for manufacturing a nanofiber filter using electrospinning.

5. In Paragraph 4, The above air injection is 0.1 kg / cm² 2 Up to 2 kg / cm² 2 Proceeding under the injection pressure conditions Method for manufacturing a nanofiber filter using electrospinning.

6. In Paragraph 1, The above spinning solution comprises a polymer compound in an amount of 10% to 30% by weight. Method for manufacturing a nanofiber filter using electrospinning.

7. In Paragraph 1, The above spinning solution comprises a high-boiling point solvent and a low-boiling point solvent. Method for manufacturing a nanofiber filter using electrospinning.

8. In Paragraph 7, The above high-boiling point solution is selected from the group consisting of DMAc(N,N-Dimethylacetoamide), DMSO(Dimethyl Sulfoxide), NMP(N-Methyl-2-pyrrolidone), DMF(Dimethylformamide), Benzyl Alcohol, and mixtures thereof. Method for manufacturing a nanofiber filter using electrospinning.

9. In Paragraph 1, The above low-boiling point solvent is selected from the group consisting of acetone, THF (Tetrahydrofuran), ethyl acetate, DCM (Dichloromethane), and mixtures thereof. Method for manufacturing a nanofiber filter using electrospinning.

10. Manufactured by a manufacturing method according to any one of paragraphs 1 to 9 Nanofiber filter.

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