KR100780346B1 - An electro-centrifugal spinning apparatus and a method for mass production of nano-fibers using the same - Google Patents

Abstract

A method for producing nanofibers and a centrifugal electrospinning apparatus for performing the method are provided to mass-produce nanofibers each having a radius of less than 1 mum, by electro-spinning polymers centrifugally in melted state or a solution state. Synthetic polymers or natural polymers are supplied to a spinner disc(8) in a melted state or a solution state. A nanofiber of three-dimensional nonwoven state is produced on a suction collector(14) by discharging the polymers on the suction collector through a spinning nozzle within the spinner disc of high voltage state, which rotates at high rate, and jetting compressed air(20) to the discharged polymer in a direction of the suction collector from the spinner disc.

Description

{An electro-centrifugal spinning apparatus and a method for mass production of nano-fibers using the same}

1 is a schematic configuration diagram of a centrifugal electrospinning apparatus of the present invention.

Figure 2 is a schematic diagram of the spinneret of the centrifugal electrospinning apparatus of the present invention.

3 and 4 is a cross-sectional view of the spinneret in which the nozzle is designed on the side and bottom in the centrifugal electrospinning apparatus of the present invention.

5 is a digital image photograph of a pitch fiber produced according to an embodiment of the present invention.

Figure 6 is a scanning electron microscope (SEM) photograph of the PAN nanofibers prepared according to an embodiment of the present invention.

Figure 7 is a scanning electron microscope (SEM) photograph of the PVA nanofibers prepared according to an embodiment of the present invention.

The present invention relates to the centrifugal electrospinning apparatus and the mass production of nanofibers using the same, and more particularly, to melt and solution spinning thermosetting and thermoplastic polymers, and to have a fiber diameter of less than 1 μm. It relates to a mass production method of nanofibers by centrifugal electrospinning that can be produced in nanosize.

Recently, by the development of nano spinning technique, ultra-fine nanofibers having a diameter of nano size (1 to 1,000 nm) are manufactured, and the ultra-high specific surface area, nano-size effect, and ultra-molecular arrangement effect of nanofibers are produced. The use of textiles is expanding from the traditional garments to all industries such as IT (information technology), bio, medical, environment, welfare, safety and energy.

Generally known nano spinning techniques include melt-blown spinning, flash spinning, composite spinning, and centrifugal spinning, but most effectively produce nanofibers. The technique may be an electrospinning method. Electrospinning is the electrospinning of polymer chains by applying a high voltage to a polymer solution or melt and uses an electric field generated between the cathode (-) and the anode (+) to measure tens to hundreds of nanometers in diameter. It is a process of obtaining the nonwoven web which consists of a fiber.

However, the electrospinning technique has limitations in producing a large amount of fibers such as interference and repulsion of electric fields between nozzles due to an applied electric field between the spinneret and the collecting suction collector, and producing nanometer-sized nanofibers for polymer melts. It is known.

Republic of Korea Patent Registration 10-5049145 discloses a method for producing ultra-fine nanofiber web by the electro- blow spinning method. The registered patent proposes a method of organically combining the electrospinning method and the melt-spinning (melt-blown spinning) technique to produce a large amount of nanofiber, but is prepared by dissolving the polymer in a solvent It is difficult to manufacture polymers that are vulnerable to solvents or polymers that are insoluble in solvents, and nanofibers prepared using polymer solutions are difficult to completely remove organic solvents, which limits their use in bio and medical applications. It is expected that additional secondary facilities such as recovery will be expensive.

In addition, the centrifugal spinning technique may be mentioned as a method capable of spinning a large amount of short fibers in the nanospinning technique. Centrifugal spinning technique is similar to cotton candy manufacturing method, and it is effective to supply polymer melt to spinner rotating at high speed, and to produce inorganic fiber or metal fiber in the state of short fiber of several to several tens of micrometer diameter by using centrifugal force of spinner. Way.

Korean Patent Registration No. 10-04715549 describes a method for producing a lyocell fiber having a diameter of several to several tens of micrometers by using a centrifugal spinning technique. However, centrifugal spinning alone produces a nanometer-sized fiber. There seems to be a limit to this.

Accordingly, the present invention simultaneously improves the disadvantages of mass production and polymer melt spinning with the electrospinning and electro-blowing methods and the disadvantages of nanofiber manufacturing with centrifugal spinning while simultaneously reducing the polymer melt and solution by nanometer size. In order to provide a way of mass production.

The present invention devised to solve the above problems, it is possible to melt the polymer (melt) and solution (solution), metal (ceramic), ceramic (ceramic) resin spinning while producing a fiber diameter of less than 1㎛ nanosize It is an object of the present invention to provide a method for mass production of nanofibers by centrifugal electrospinning.

The present invention for achieving the above object
A spinner disc subjected to a high voltage and rotating at high speed, a means for discharging molten or solution-synthesized or natural polymer from the spinneret in the spinner disc onto the suction collector, and at the same time as the discharge, It provides a nanofiber manufacturing apparatus by centrifugal electrospinning, characterized in that for manufacturing the nanofiber of the three-dimensional non-woven state on the suction collector by including a means for blowing compressed air in the direction.

In addition, the present invention is supplied to the spinner disk in the molten or solution state of the synthetic or natural polymer, and discharges the polymer melt or solution onto the suction collector through the spinning nozzle in the high-voltage spinner disk is rotating at high speed, The present invention further provides a method for producing nanofibers by centrifugal electrospinning, wherein the compressed air is ejected from the spinner disk in the direction of the suction collector to produce nanofibers in a three-dimensional nonwoven fabric on the suction collector. .

In addition, the present invention further provides a method for producing nanofibers by centrifugal electrospinning, characterized in that the rotational speed of the spinner disk is 1 to 3000 rpm.

In addition, the present invention further provides a method for producing nanofibers by centrifugal electrospinning, in which the voltage applied to the spinner disk is 1 to 100 kV.

In another aspect, the present invention further provides a method for producing nanofibers by centrifugal electrospinning, characterized in that an orifice is formed on the side or bottom of the spinner disk.

In addition, the present invention further provides a method, characterized in that the nanofibers are carbon nanofibers or activated carbon nanofibers.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.
Referring to the centrifugal electrospinning of the present invention with reference to Figures 1 and 2 as follows. Spinner discs that rotate at high voltage and high speed in the apparatus correspond to 8, and are provided with a spinneret (not shown) therein. Since the spinning nozzle is provided inside the spinner disk, although not shown in the drawing, an orifice 21 of FIG. 3 may be formed at the end of the nozzle, for example.
Means for supplying synthetic or natural polymers in a molten or solution state are, for example, a hopper extruder 2, a heating unit 3, a metering pump 4, a valve 5, as shown in FIG. It may have the same configuration as the insulating portion 6-radiation bracket 7.
In addition, the discharge of the supplied solution or solution is made by centrifugal force and voltage formed on the spinner disk. That is, it is discharged out of the spinning nozzle by the centrifugal force generated in the spinner disk rotating at high speed and the high electric field formed between the spinner disk and the suction collector. The centrifugal force generating means may be the motor 7 described in FIG. 1 and the identification symbol, and the voltage generating means may be configured as shown, for example, by reference numeral 10 in FIGS. 1 and 2.
In addition, the means for ejecting the compressed air, for example, as shown in Figs. 1 and 2, the air guide 9 formed around the outer periphery of the spinneret 7 and the spinneret 7 ) And the air heater 25 and the air compressor 11 for ejecting the compressed air 20 in the same direction as the lower direction in the drawing, that is, the discharge direction of the polymer between the air guide (9). have.
In addition, the suction collector for collecting the discharged melt or solution to produce a nanofiber of a three-dimensional non-woven state may be configured as shown in the reference numeral 14 shown in FIGS.

In the method of manufacturing nanofibers by the centrifugal electrospinning of the present invention, the polymer melt and the polymer solution dissolved in the solvent are supplied to the spinner disk, and the supplied polymer melt and the solution are centrifugal force and spinner generated on the spinner disk rotating at high speed. It is discharged out of the spinning nozzle by a high electric field formed between the disk and the suction collector. Meanwhile, compressed air is applied to the discharge liquid in the same direction as the direction from the spinner disc to the suction collector (for example, arrow direction indicated by reference numeral 20), whereby 3 nanofibers are placed on the suction collector grounded below. It is captured in the dimensional nonwoven state.

1 and 2 is a configuration diagram of the centrifugal electrospinning apparatus for explaining such a manufacturing method, Figures 3 and 4 is a configuration diagram of the spinneret having a spinneret on the side and bottom. Hereinafter, the present invention will be described in detail a centrifugal electrospinning apparatus and a mass production method of nanofibers using the same.

As the polymer material used in the present invention, all polymers such as synthetic polymers and natural polymers may be used. In the case of melt spinning, the polymer chips 1 are supplied to a hopper and heated while being transported through the extruder 2. The part (3) is heated to 30-50 ° C. or more above the melting temperature to melt the polymer. The polymer melt is transferred to the spinneret 7 and the spinner disk 8 through the metering pump 4 and the insulator 6. Although the extruder was used to transfer the polymer melt in the present invention, a conventional transfer method may be used, and there is no particular limitation. In the case of solution spinning, the polymer chip 1 is dissolved in a solvent capable of dissolving and supplied through a metering pump 4. The polymer chip 1 may be master batched by mixing various types of resins according to the purpose of use, and a material compatible with a solvent may be used. As the mixed resin, various forms such as a light stabilizer, a curing agent, a crosslinking agent, an initiator, and the like may be dispersed and used according to the final purpose of the nanofibers.

The spinneret 7 is connected to the insulated motor 7 to rotate at high speed, and is connected to the high voltage generator 10 so that the polymer melt is discharged by the spinner disk 8. The spinneret is formed by discharging the compressed air 23 by the air guide 9 of the cylinder to the compressed air 23 through the air output of the compressed air through the air compressor 11 and the air heater 25 and the force of the voltage. ) Is finally collected on the suction collector 14 while spinning into nanofibers. The collected nanofibers are compressed by the calendar 16 and finally focused on the bobbin 17 in roll form. The distance 24 between the spinneret and the suction collector 14 is set to 10-150 cm and can be adjusted while looking at the spinning state.

The spinneret has a configuration such that the spinneret 7 and the spinner disk 8 are connected to the rotary shaft 19 to rotate at high speed, as shown in FIGS. 3 and 4, and the spinner disk 8 has an orifice. (orifis) 21 is configured on the side and bottom, the compressed air to be able to adjust the direction by the air guide (9) and the shield (22). In addition, the spinner disk is designed to generate heat, and for example, a method used in a conventional centrifugal spinning apparatus such as the method described in Korean Patent Registration No. 1988-0001739 may be used.

In the present invention, the range of the rotational speed and the applied voltage of the spinner disk is not particularly limited, but in consideration of the miniaturization of the fiber to be manufactured and the device operability, the range of about 1 to 3000 rpm and the range of 1 to 100 kV. It is preferable to set it as.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited only to the following examples.

Example 1.

A petroleum-based isotropic pitch with a softening point of 256 ° C is supplied to the hopper using the raw material 1, and the temperature of the extruder 2 is divided into three stages by the heating section 3 to 250, 280, and 310 ° C. It was melted sufficiently while heating. The molten isotropic pitch was quantitated 30 cc / min by the metering pump 4 and transferred to the spinneret. At this time, the structure of the spinner disk used was used in Figure 4, the temperature of the spinner disk is about 300 ℃, about 50 ℃ higher than the softening temperature of the raw material pitch, and the rotation speed of the spinner disk is 2000 rpm per minute It was. The distance between the spinneret and the suction collector 12 was about 50 cm and the voltage applied to the spinner disk was 50 kV. A digital image photograph of the fiber obtained at this time is shown in FIG. 5, and the diameter distribution has a range of about 500 to 1000 nm, and an isotropic pitch fiber of uniform quality was obtained at an average of 800 nm.

The pitch fiber thus obtained was oxidized to 300 ° C. at a rate of 1 ° C. per minute in air through a hot air circulation path to obtain an incompatible (stabilized) fiber. The obtained infusible fibers were carbonized to 1000 ° C. in an inert atmosphere to produce carbon nanofibers. The average diameter distribution of the produced carbon fibers was in the range of about 500 nm. Activated carbon nanofibers were obtained by activating the obtained infusible fibers or carbonized fibers at an activation temperature of 700, 800, and 900 ° C. for 1 hour using steam. The specific surface area of the activated carbon nanofibers thus obtained was measured using -77K nitrogen gas. The results are shown in Table 1.

Surface Characteristics of Isotropic Pitch-Based Activated Carbon Nanofibers Activation temperature (℃) Activation yield (%) Specific surface area (㎡ / g) Average pore size (nm) 700 45 1500 1.9 800 35 2000 2.1 900 15 2500 2.3

Example  2

Polyacrylonitrile (PAN) was dissolved in dimethyl acetamide (dimethylacetamide, DMF) at 30% by weight to prepare a spinning solution. The prepared spinning solution was quantified by 50cc per minute using a metering pump as in the method of Example 1 and transferred to the spinneret. At this time, the shape of the spinner disk was used that the orifice is configured on the side shown in Figure 3, the rotation of the spinner disk was 2800rpm per minute, the applied voltage was 50kV. Centrifugal electrospinning was performed at a distance of 30 cm between the spinneret and the suction collector. The electron micrograph of the fiber obtained at this time is shown in FIG. As shown in the figure, it could be confirmed that fibers composed of ultra-fine nanofibers having an average diameter of about 400 nm were stacked. The nanofibers thus obtained were transferred to a calender 16 heated at 100 ° C., and finally pressed to prepare nanofibers.

Example 3

Polyvinyl alcohol (polyvinylachol, PVA, DP = 2000) was dissolved in water to 30% by weight and centrifugal electrospinning was carried out in the same manner as in Example 2. The scanning electron micrograph of the nanofiber obtained at this time is shown in FIG. As shown in FIG. 7, a PVA nanofiber having a diameter of 200 nm was successfully manufactured.

The present invention can easily produce a large amount of nanofibers composed of synthetic polymers and natural polymers of less than 1 ㎛ in diameter by centrifugal electrospinning, and there is an effect that a method such as melting and solution can be used to meet the polymer properties.

Claims (6)

Spinner disks that are subjected to high voltage and rotate at high speed, Means for discharging molten or solution synthetic or natural polymer from the spinneret in the spinner disc onto the suction collector; Means for ejecting compressed air from the spinner disc in the direction of the suction collector simultaneously with the discharge; The apparatus for producing nanofibers by centrifugal electrospinning, characterized in that nanofibers of a three-dimensional non-woven state are manufactured on the suction collector. Synthetic or natural polymer is supplied to the spinner disk in molten or solution state, The polymer melt or solution is discharged onto the suction collector through a spinning nozzle in a high voltage spinner disc rotating at high speed, and compressed air is ejected from the spinner disc in the direction of the suction collector to the suction collector. Method for producing nanofibers by centrifugal electrospinning, characterized in that to produce nanofibers in a three-dimensional nonwoven fabric. The method of manufacturing nanofibers by centrifugal electrospinning according to claim 2, wherein the spinner disk has a rotation speed of 1 to 3000 rpm. The method of claim 2, wherein the voltage applied to the spinner disk is 1 to 100 kV. The method of claim 2, wherein an orifice is formed on the side or bottom of the spinner disk. The method of claim 2, wherein the nanofibers are carbon nanofibers or activated carbon nanofibers.

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