Melt-jet electrospinning apparatus for manufacturing ultrafine nanofiber nonwoven fabric

Abstract

The present invention relates to a melt-jet electrospinning apparatus for manufacturing an ultrafine nanofiber nonwoven fabric. The melt-jet electrospinning apparatus for manufacturing an ultrafine nanofiber nonwoven fabric comprises: an extruder for producing a polymer melt solution; a gear pump for quantitatively transporting the melt solution from the extruder; a spinning nozzle through which the polymer melt solution transferred from the gear pump is discharged; a collector for collecting the spun fiber discharged from the spinning nozzle in a web state; and a voltage-applying means for applying a high voltage between the spinning nozzle and the collector. The spinning nozzle comprises: an upper spinning nozzle die provided with a spinneret for discharging the polymer melt solution; and a lower spray nozzle die disposed to face the upper nozzle die and provided with a spray nozzle through which air and the polymer melt solution are discharged from two-direction air flow paths and the lower portion of the spinneret. An air flow path angle formed by the two-direction air flow paths is 30-90 degrees, and thus an ultrafine nanofiber nonwoven fabric can be mass-produced by using a thermoplastic polymer without using environmentally harmful solvents, compared to an existing solution electrospinning method.

Description

Melt-jet electrospinning device for manufacturing ultra-fine nanofiber nonwoven fabrics

[0001] The present invention relates to a melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric, and more specifically, to an environmentally friendly ultra-fine nanofiber nonwoven fabric producing device that does not use a solvent during electrospinning.

[0002] Recently, the demand for nonwoven fabrics has been rapidly increasing worldwide due to their diverse uses, and the demand for ultrafine fiber and nanofiber nonwoven fabrics is also increasing further.

[0003] The manufacturing technology for these ultra-fine nanofiber nonwoven fabrics primarily relies on solution electrospinning. Solution electrospinning involves dissolving a polymer in a solvent to create a polymer solution, which is then spun into a high-voltage electric field formed between a spinning needle and a collecting plate to produce nanofibers.

[0004] However, this solution electrospinning method requires a solvent recovery process during the manufacturing process due to the solvent used, and there are problems with the environment and safety, such as solvent residue in the final product.

[0005] Meanwhile, a melt electrospinning method has been proposed to improve this, but insulation problems are raised when high voltage is applied to the spinning nozzle, and it is difficult to maintain the spinning temperature and keep it warm.

[0006] In addition, an insulating layer is introduced to the radiation nozzle to provide insulation, but this makes it difficult to maintain the radiation temperature and insulate the nozzle surface, which has a detrimental effect on the production of nanofibers.

[0007] Also, as in Korean Patent Publication No. 2012-0015655, a method of heating a melting tank using a gas heating method has been attempted to facilitate insulation of a spinning nozzle and to manufacture and maintain the temperature of a melt. However, the device becomes complicated due to the gas heating and circulation device, and as it is a laboratory device rather than a roll-to-roll method, it is not effective in mass production of nanofibers.

[0008] Currently, the method for commercially producing nanofiber nonwoven fabrics is mainly solution electrospinning, which uses a solution tank and a needle-type spinning nozzle, but it is known to be insufficient for mass production of nanofibers.

[0009] To mass-produce nanofibers without using environmentally harmful solvents, melt-jet electrospinning, which organically combines existing electrospinning and melt-blown spinning technologies, is the most realistic method, but research on this is limited.

[0010] The technical problem to be achieved by the present invention is to provide a device for manufacturing an ultra-fine nanofiber nonwoven fabric of a thermoplastic polymer while maintaining insulation and heat retention of the spinneret and simultaneously applying a high voltage between the spinneret and the collector, and without using an environmentally harmful solvent.

[0011] Another technical problem to be solved by the present invention is to provide a melt jet electrospinning device that promotes nanofiberization of electrospun fibers by increasing fiberization shear force using high-temperature and high-pressure hot air while maintaining insulation and heat retention of the spinning nozzle to achieve the above-mentioned technical problem.

[0012] In order to achieve the above-mentioned object, the melt-spray electrospinning device for producing ultra-fine nanofiber nonwoven fabric according to the present invention comprises: an extruder for producing a polymer melt; a gear pump for quantitatively transferring the polymer melt from the extruder; a spinneret through which the polymer melt transferred from the gear pump is discharged; a collector for collecting the spun fibers discharged from the spinneret in a web state; and a voltage applying means for applying a high voltage between the spinneret and the collector.

[0013] The above radiation nozzle is,

[0014] Provided is a melt-spray electrospinning device for producing ultra-fine nanofiber nonwoven fabric, comprising: an upper spinneret die provided with a spinneret for discharging a polymer melt; and a lower spinneret die provided with an air path in both directions and a spray hole for discharging air and a polymer melt from below the spinneret, the lower spinneret die being positioned so as to face the upper nozzle die, wherein the air path angle formed by the two air paths meeting is 30 to 90 degrees.

[0015]

[0016] In addition, a distance (e) between the radiator of the upper radiator nozzle die and the radiator of the lower spray nozzle die is in the range of -10 to 10 mm, and a melt-spray electrospinning device for producing ultra-fine nanofiber nonwoven fabric is provided, characterized in that it satisfies the following equation (1).

[0017] [Formula 1]

[0018] -10d≤e≤10d

[0019] (In Equation 1, e represents the distance between the radiator of the upper radiating nozzle die and the radiator of the lower injection nozzle die, and d represents the diameter of the radiator.)

[0020]

[0021] In addition, the diameter (a) of the air path is in the range of 0.2 to 10 mm, and a melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric is provided, characterized in that it satisfies the following equation (2).

[0022] [Formula 2]

[0023] 2d≤a≤10d

[0024] (In Equation 2, a represents the diameter of the air path, and d represents the diameter of the radiator.)

[0025]

[0026] In addition, a melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric is provided, characterized in that the diameter (d) of the spinneret of the upper spinneret die is in the range of 0.1 to 1.0 mm, and the ratio (L / d) of the length (L) and diameter (d) of the spinneret is 1 to 20.

[0027]

[0028] In addition, the present invention provides a melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the upper spinneret die includes 1 to 50 spinnerets per inch in the width direction of the spinneret.

[0029]

[0030] In addition, the device provides a melt-jet electrospinning device for manufacturing ultra-fine nanofiber nonwoven fabric, characterized in that the upper spinneret die of the spinneret is grounded and a high voltage is applied to the collector.

[0031]

[0032] In addition, the present invention provides a melt-jet electrospinning device for manufacturing ultra-fine nanofiber nonwoven fabric, characterized in that the high voltage has positive polarity and the voltage is about 1 to 200 kV.

[0033]

[0034] In addition, the present invention provides a melt-jet electrospinning device for manufacturing ultra-fine nanofiber nonwoven fabric, characterized in that the high voltage has a negative polarity and a voltage of about 1 to 200 kV.

[0035] According to the melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric of the present invention, ultra-fine nanofiber nonwoven fabric can be mass-produced using a thermoplastic polymer without using an environmentally harmful solvent compared to the existing solution electrospinning method, and nanofibers having a fiber diameter of less than 1 ㎛ can be obtained by maintaining the angle of the air flow path small.

[0036] In addition, quantitative transfer of polymer melt is possible by using an extruder and a gear pump, insulation and heat preservation of the spinneret can be maintained, nanofibers can be obtained without using a harmful solvent by applying a high voltage between the spinneret and the collector, and nanofibers having a desired fiber diameter can be obtained by forming the spinneret spacing, spinneret diameter, and air flow angle and diameter differently.

[0037] The nanofiber nonwoven fabric manufactured according to the present invention can be very usefully used as an industrial material, a material for electrical and electronic components, a material for a separator, etc.

[0038] Figure 1 is a schematic diagram of a melt-jet electrospinning device according to the present invention.

[0039] Figure 2 is a diagram of a radiant nozzle configuration for explaining the radiant nozzle's radiant orifice and injection nozzle.

[0040] In order to fully understand the present invention, preferred embodiments of the present invention will be described with reference to the attached drawings.

[0041]

[0042] The embodiments of the present invention may be modified in various ways, and the scope of the present invention should not be construed as limited to the embodiments detailed below. These embodiments are provided to more fully explain the present invention to those of ordinary skill in the art. Detailed descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention are omitted.

[0043]

[0044] Referring to FIG. 1, the melt-jet electrospinning device according to the present invention is composed of a hopper (10) for supplying polymer chips, an extruder (20) for producing a polymer melt, a gear pump (G / P) for quantitatively transporting the melt from the extruder, and a spinning nozzle (101) through which the polymer melt transported from the gear pump (G / P) is discharged.

[0045] In addition, it includes a collector (110) that collects the radiant fibers discharged from the radiant nozzle (101) in a web state, and a high voltage generator (120) that is a voltage applying means that applies a high voltage between the radiant nozzle (101) and the collector (110).

[0046] In addition, an air collection tube (114) that collects air discharged from the radiating nozzle (101) by suction is installed in the collector (110), and an air suction device (112) that sucks in and discharges the air collected by suction is connected to the air collection tube (114).

[0047] In addition, the above-mentioned radiation nozzle (101) is composed of an upper radiation nozzle die (102) provided with a radiation port (104) for discharging a polymer melt, and a lower injection nozzle die (103) provided with a spray port (106) that is positioned so as to face the upper nozzle die (102) and through which air and the polymer melt are discharged from the lower part of the air path and the radiation port.

[0048] In addition, the above device is connected to an air compression blower (109) that supplies air to supply high temperature and high pressure air to the air path of the radiating nozzle (101) and a heater (heat tank) (108) that heats the air.

[0049] A melt-blown electrospinning device is a device that implements melt-blown electrospinning, a spinning method that organically combines melt-blown and electrospinning. In this case, melt-blown electrospinning can be used as a concept similar to melt-blown electrospinning.

[0050] The air flow angle (α) formed by the two-way air flow paths of the spin nozzle of the above-mentioned melt-jet electrospinning device meeting each other may be 30 to 90 degrees (°), preferably 30 to 60 degrees.

[0051] In manufacturing ultra-fine nanofibers using high-temperature, high-pressure hot air, the air flow angle (α) plays an important role.

[0052] The smaller the air flow angle, the greater the fiber shear force caused by the high temperature and high pressure hot air, which results in favorable results for nanofiber production.

[0053] In addition, the distance between the nozzles can be moved toward the inside of the nozzle, making it easier to keep the discharged polymer warm, which can be more advantageous for manufacturing nanofibers.

[0054] However, if the air flow angle is too small, less than 30 degrees, it causes problems such as increased processing costs and reduced durability of the radiating nozzle.

[0055] Therefore, an air flow angle of 30 to 90 degrees is advantageous in terms of processing cost and durability, and preferably, an air flow angle of 30 to 60 degrees produces better results.

[0056] The distance (e) between the radiator of the upper radiating nozzle die (102) and the radiator of the lower spray nozzle die (103) is in the range of -10 to 10 mm, preferably in the range of -5 to 5 mm, and may be a melt-spray electrospinning device for producing ultra-fine nanofiber nonwoven fabric satisfying the following formula (1).

[0057] [Formula 1]

[0058] -10d≤e≤10d

[0059] (In Equation 1, e represents the distance between the radiator of the upper radiating nozzle die and the radiator of the lower injection nozzle die, and d represents the diameter of the radiator.)

[0060] When the radiator (104) of the upper radiator nozzle die (102) rises toward the inside of the radiator (106) of the lower injection nozzle die (103), it is expressed as a - (minus) distance, and when the radiator (104) of the upper radiator nozzle die (102) protrudes below the radiator (106) of the lower injection nozzle die (103), it is expressed as a + (plus) distance.

[0061] The distance between the radiator (104) is advantageous for maintaining the heat retention and radiant temperature of the polymer as it moves toward the inside of the lower nozzle die (103) injection port (106), and as a result, nanofibers with a smaller fiber diameter can be manufactured.

[0062] In addition, the distance between these radiators (104) has a dependence on the diameter (d) of the polymer radiator and can be advantageous for manufacturing nanofibers when it satisfies the above equation (1).

[0063] As the diameter of the radiator (104) becomes smaller, the radiator spacing range becomes smaller, and as the diameter of the radiator (104) becomes larger, the radiator spacing range can increase.

[0064]

[0065] In addition, even when the radiator separation distance is inside the nozzle (106), the radiator separation distance is dependent on the diameter of the radiator, and the distance must be limited. That is, the smaller the radiator diameter, the smaller the radiator separation distance must be.

[0066] The further the distance between the radiator nozzles is inside the nozzle, the more advantageous it is for heat retention. However, this is because the disturbance caused by adjacent radiator nozzles and the concentration of the electric field at the tip of the nozzle face can be hindered, which can have a detrimental effect on the nanofiberization of the ejected polymer.

[0067] In addition, even if the radiator gap distance protrudes outside the nozzle, the radiator gap distance is dependent on the radiator diameter and must be limited. That is, the smaller the radiator diameter, the smaller the radiator gap distance must be.

[0068] This is because the greater the distance at which the radiator protrudes outside the nozzle, the more difficult it is to keep the discharged polymer warm, which acts as an obstacle to nanofiberization of the discharged polymer.

[0069] As mentioned above, it can be said that it is advantageous to keep the distance between the radiator nozzles small in cases where it does not interfere with the nanofiberization and spinning workability of the radiant fiber.

[0070] The diameter (a) of the above air path is in the range of 0.2 to 10 mm, preferably in the range of 0.2 to 5.0 mm, and may be a melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric satisfying the following formula (2).

[0071] [Formula 2]

[0072] 2d≤a≤10d

[0073] (In Equation 2, a represents the diameter of the air path, and d represents the diameter of the radiator.)

[0074]

[0075] The air flow diameter is dependent on the radiator diameter, and as the radiator diameter increases, the air flow diameter can increase.

[0076] The above-mentioned upper radiation nozzle die (102) may be a melt-jet electrospinning device in which the diameter (d) of the spinneret (104) is in the range of 0.1 to 1.0 mm, and the ratio (L / d) of the length (L) and diameter (d) of the spinneret (104) is 1 to 40, and preferably, the diameter (d) of the spinneret may be 0.1 to 0.5 mm, and the ratio (L / d) of the length (L) and diameter (d) of the spinneret may be 5 to 20.

[0077] If the diameter (d) of the spinneret is less than 0.1 mm or the ratio (L / d) of the length (L) and diameter (d) of the spinneret exceeds 40, processing of the spinneret (104) is difficult and is disadvantageous in terms of processing cost. Furthermore, the phenomenon of clogging of the spinneret hole during spinning increases, which lowers the uniformity of the nanoweb and causes disadvantageous problems in terms of spinning workability.

[0078]

[0079] The upper spinneret die (102) of the above melt-jet electrospinning device may include 1 to 50 spinnerets (104) per inch in the width direction of the spinneret (101), and preferably 2 to 20 spinnerets (104) per inch.

[0080] If the number of the above-mentioned radiation holes (104) increases excessively, radiation from adjacent radiation holes may be disturbed during radiation, which may have a detrimental effect on the production of nanofibers.

[0081]

[0082] The above-mentioned melt-jet electrospinning device can ground the upper spinneret die (102) of the spinneret (101) and apply a high voltage to the collector (110) by a high voltage generator (120).

[0083] Electrospinning is performed by applying an electric field by high voltage between the spinneret (101) and the collector (110). In this case, when applying a high voltage to the spinneret (101), it is necessary to introduce a separate insulating layer to prevent damage to electrical devices such as the extruder (20) due to the high voltage. However, in this case, it is difficult to keep the polymer warm by the insulating layer, and it is also disadvantageous to maintain the spinning temperature.

[0084] The above high voltage has a positive polarity and may be approximately 1 to 200 kV, preferably 5 to 100 kV. If the voltage exceeds 200 kV, insulation may be difficult and may affect surrounding electrical devices, resulting in device failure.

[0085] The above high voltage has a negative polarity and may be approximately 1 to 200 kV, preferably 5 to 100 kV. If the voltage exceeds 200 kV, insulation may be difficult and may affect surrounding electrical devices, resulting in device failure.

[0086]

[0087] The polymer of the present invention may be polypropylene, polyethylene, polytetrafluoroethylene, polyester, polyamide, polyacrylonitrile, polyurethane, polyvinyl alcohol, etc., and any thermoplastic polymer may be used without limitation. Among these thermoplastic polymers, polypropylene may be suitable for use in terms of price and stability.

[0088]

[0089] Hereinafter, the present invention will be described in detail by examples.

[0090] However, the following examples are only illustrative of the present invention, and the content of the present invention is not limited by the following examples.

[0091]

[0092] <Example 1>

[0093] Polypropylene (PP) chips having a melt flow index (MI) of 1400 as a thermoplastic polymer were supplied to an extruder (20) through a hopper (10) to produce a spinning melt, which was then quantitatively transferred to the spinning nozzle (101) of Fig. 1 using a gear pump (G / P). Continuously, the spinning melt was melt-blown (melt-sprayed) through the upper spinning nozzle die (102) and the lower spray nozzle die (103) in the grounded spinning nozzle (101) to a collector (110) to which a positive electrode was attached, thereby producing a nanofiber nonwoven fabric.

[0094] The melt-jet electrospinning device used in the example at this time was a knife-edge-shaped spinneret with an air flow angle (α) of 60 degrees (°) as shown in Fig. 1. The diameter of the spinneret (101) used at this time was 0.25 mm, the L / d of the spinneret was 10, the number of spinnerets of the spinneret was 10 / in, the air gap, which is the diameter of the air flow, was 1.50 mm, and the separation distance of the spinnerets was -0.5 mm.

[0095] In addition, the process conditions were adjusted to the temperature of the extruder (20) and the radiation nozzle die to set the room temperature to 270℃, the DCD (Die to collector distance), which is the distance between the radiation nozzle die and the collector (110), was set to 200mm, and the air flow rate of the heated air of the air flow path (air injection port) was 8m 3 / min, wind speed is 28kPa, temperature of heated air is 250℃, basis weight is 10gsm (g / m 2 ) level nanofiber nonwoven fabric was manufactured. At this time, a high voltage of 60 kV was applied to the collector (110) by a high voltage generator (120). The average fiber diameter of the manufactured nonwoven fabric is shown in Table 1 below.

[0096]

[0097] <Examples 2 and 3>

[0098] The same procedure as Example 1 was followed to manufacture the product, but the distance between the radiator tubes was changed to 0 mm and +0.5 mm, respectively.

[0099]

[0100] <Examples 4 to 9>

[0101] The same process as Example 1 was used for manufacturing, but the air flow angle and the distance between the radiator holes were changed as shown in Table 1 below.

[0102]

[0103] <Comparative Example 1>

[0104] The same process as Example 1 was used for manufacturing, but the air flow angle and the distance between the radiator holes were changed as shown in Table 1 below.

[0105]

[0106] Experimental Example 1

[0107] The following physical properties were evaluated for the nanofiber nonwoven fabrics manufactured through Examples 1 to 9 and Comparative Example 1, and are shown in Table 1 below.

[0108]

[0109] 1) Average fiber diameter

[0110] The manufactured nanofiber nonwoven fabric was cut into circles of 10 cm in diameter at three locations: the left, right, and center. The surface of each specimen was photographed using an SEM to measure the fiber diameter. The diameters of 10 fibers per specimen were measured, and the average fiber diameter was calculated and expressed in nanometers (nm). To reduce measurement errors, the unit of measurement was rounded down to the nearest tenth place.

[0111]

[0112] 2) Comprehensive evaluation

[0113] The fiber diameter properties of the nanofiber nonwoven fabrics manufactured in Examples 1 to 9 and Comparative Example 1 were measured and evaluated. If the average fiber diameter was less than 900 nm, it was judged as good (○), if the average fiber diameter was less than 900 to 1200 nm, it was judged as average (△), and if the average fiber diameter was 1200 nm or more, it was judged as poor (×).

[0114]

[0115] Distance between the radiator and the air flow angle (°) * (㎜) Average fiber diameter (㎚) Comprehensive evaluation Example 160-0.5860 ○ Example 20820 ○ Example 3 + 0.5750 ○ Example 430-0.5810 ○ Example 50760 ○ Example 6 + 0.5720 ○ Example 790-0.51160 △ Example 801040 △ Example 9 + 0.5970 △ Comparative example 110001330 ×

[0116] * Explanation of the radiation hole separation distance symbol

[0117] When the radiator separation distance is minus (-), it means that the radiator is inside the radiator (106) of the lower radiator nozzle die (103), i.e., inward. When the radiator separation distance is 0, it means that the radiator (104) is at the same surface position as the radiator of the lower radiator nozzle die (103). When the radiator separation distance is plus (+), it means that the radiator (104) is outside the radiator of the lower radiator nozzle die (103), i.e., protrudes outward.

[0118]

[0119] As can be seen in Table 1, when the air flow angle is 60 degrees, it was found that an ultra-fine nanofiber nonwoven fabric with an average fiber diameter of 900 nm or less could be manufactured.

[0120] Furthermore, it was confirmed that when the air flow angle is 30 degrees, an ultra-fine nanofiber nonwoven fabric with an even smaller average fiber diameter can be manufactured.

[0121] When the airflow angle was 90 degrees, it was found that the average nanofiber diameter increased compared to when the airflow angle was 30 degrees or 60 degrees.

[0122] This phenomenon can be evaluated as a phenomenon in which the smaller the air flow angle, the greater the fiber shear force caused by the injected air, thereby promoting nanofiber formation.

[0123] In addition, when the radiator (104) protrudes outside the radiator (106) of the lower radiator nozzle die (103), it is evaluated that the electric field caused by the high voltage applied between the radiator nozzle (101) and the collector (110) is easily concentrated at the tip of the nozzle, thereby promoting nanofiberization.

[0124] Meanwhile, it was found that nanofibers were produced even when the distance between the radiator nozzles was inside the nozzle when the air flow angle was small.

[0125] In addition, even if the radiator gap distance protrudes outside the nozzle, the radiator gap distance is dependent on the diameter of the radiator, and the distance must be limited.

[0126] That is, the smaller the diameter of the radiator, the smaller the distance between the radiators should be. This is because the larger the distance between the radiators, the more difficult it is to keep the discharged polymer warm, which acts as an obstacle to nanofiberization of the discharged polymer.

[0127] As mentioned above, in cases where there is no interference with the nanofiberization and spinning workability of the radiant fiber, it may be advantageous to keep the spinneret spacing small.

[0128]

[0129] In Comparative Example 1, where the air flow angle was 100 degrees, the average fiber diameter greatly exceeded 1000 nm, and the fiber diameter distribution also increased. This phenomenon is believed to have occurred because the large air flow angle reduced the fiberizing shear force caused by the injected air, and also increased air disturbance to adjacent spinnerets.

Claims

1. An extruder for producing a polymer melt; a gear pump for quantitatively transferring the melt from the extruder; a spinning nozzle for discharging the polymer melt transferred from the gear pump; a collector for collecting the spun fibers discharged from the spinning nozzle in a web state; and Including a voltage applying means for applying high voltage between the above-mentioned radiation nozzle and the collector, The above radiation nozzle is, A melt-spraying electrospinning device for manufacturing an ultra-fine nanofiber nonwoven fabric, comprising: an upper spinneret die provided with a spinneret for ejecting a polymer melt; and a lower spinneret die arranged to face the upper nozzle die and provided with air paths in both directions and a spinneret through which air and a polymer melt are ejected from the lower portion of the spinneret, wherein the air path angle formed by the meeting of the air paths in both directions is 30 to 90 degrees.

2. In paragraph 1, A melt-spray electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the distance (e) between the radiator of the upper radiator nozzle die and the radiator of the lower spray nozzle die is in the range of -10 to 10 mm and satisfies the following equation (1). [Formula 1] -10d≤e≤10d (In Equation 1, e represents the distance between the spinneret of the upper spinneret die and the spinneret of the lower injection nozzle die, and d represents the diameter of the spinneret.) 3. In paragraph 1, A melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the diameter (a) of the air path is in the range of 0.2 to 10 mm and satisfies the following equation (2). [Formula 2] 2d≤a≤10d (In Equation 2, a is the diameter of the air path, and d is the diameter of the radiator.) 4. In paragraph 1, A melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the diameter (d) of the spinneret of the upper spinneret die is in the range of 0.1 to 1.0 mm, and the ratio (L / d) of the length (L) and diameter (d) of the spinneret is 1 to 40.

5. In paragraph 1, A melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the upper spinneret die includes 1 to 50 spinnerets per inch in the width direction of the spinneret.

6. In paragraph 1, A melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the upper radiation nozzle die of the above-mentioned radiation nozzle is grounded and a high voltage is applied to a collector.

7. In paragraph 6, A melt-jet electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the high voltage has positive polarity and a voltage of about 1 to 200 kV.

8. In paragraph 6, A melt injection electrospinning device for producing ultra-fine nanofiber nonwoven fabric, characterized in that the high voltage has negative polarity and a voltage of about 1 to 200 kV.

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