KR102116122B1 - Method for producing a filter for blocking fine dust based aligned nanofibers - Google Patents

Abstract

The present invention relates to a method for manufacturing nanofibers used as a material for a filter for removing fine dust, and more specifically, preparing a polymer solution containing a ferroelectric material (S1); Preparing the electrospinning by putting the polymer solution in a syringe (S2); Electrospinning the polymer solution in a rotating roller direction by applying a voltage to the syringe (S3); And obtaining nanofibers deposited on the rollers. The nanofibers produced by the above-described manufacturing method have an aligned shape, thereby increasing strength, and polarization occurs inside the fibers, so that the efficiency of the filter is excellent when manufacturing the filter using the nanofibers.

Description

Aligned nanofiber-based filter for blocking fine dust {METHOD FOR PRODUCING A FILTER FOR BLOCKING FINE DUST BASED ALIGNED NANOFIBERS}

The present invention relates to a method for manufacturing a filter for blocking fine dust based on nanofibers.

It is known that various fine dusts present in the atmosphere directly or indirectly affect the human body and natural ecosystems. The fine dust in the air consists of primary dust directly and indirectly discharged by artificial sources of pollution (factory chimneys, automobiles, etc.) and secondary dust generated by chemical reactions of the gaseous substances emitted.

Particularly, PM10 (Particulate Matter with a diameter less than 10㎛), which is a respirable dust or fine dust having a particle diameter of 10㎛ or less, has a relatively long residence time in the atmosphere and is deposited in the human lung, resulting in diseases related to heart disease or lung cancer. It is known to induce and can cause secondary effects such as causing light impairment and acid rain. In Korea, fine dust is caused not only by artificial pollutants, but also by yellow dust from China and Mongolia, and its damage is also serious.

Particularly, since the need for management of fine particles such as sulfate particles and soot has emerged due to the rapid increase in energy consumption and automobiles due to economic activities, particles in the fine dust existing in the atmosphere for particulate air pollutants in Korea since 1995 Microparticles (PM10) with a diameter of 10 µm or less have been set and managed as standard items for atmospheric environment.

Currently, domestic air pollution monitoring network in major metropolitan cities nationwide monitors the pollution level of particulate matter for 24 hours using measuring equipment that can automatically measure the concentration of fine dust in real time.

Recently, according to the Ministry of Environment's measurement data for fine dust, the concentration of fine dust is on a decreasing trend, but the pollution level of fine dust, which is the main culprit causing cardiopulmonary disease and clouding the sky, is getting worse.

Accordingly, research is underway to develop a filter for removing fine dust particles (Domestic Publication No. 2009-0103351). As a method for increasing the efficiency of the filter, a method of increasing the efficiency by adding specific nanoparticles or thickening the filter media thickness has been proposed. However, when the filter media thickness becomes thick, the pressure difference increases and there is a concern that the filter performance index QF may drop.

As a result of earnest research to develop an electrostatic filter having an increased efficiency for removing fine dust, the present inventors not only increase the strength but also increase the strength when the nanofibers are aligned using a polymer solution containing ferroelectric material. Polarization occurs, confirming that the efficiency of the filter can be increased, thereby completing the present invention.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problems, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the object of the present invention as described above, the present invention provides a method of manufacturing an aligned nanofiber comprising the following steps:

Preparing a polymer solution containing a ferroelectric (S1);

Preparing the electrospinning by putting the polymer solution in a syringe (S2);

Electrospinning the polymer solution in a rotating roller direction by applying a voltage to the syringe (S3); And

Obtaining nanofibers deposited on the roller.

As one embodiment of the present invention, the ferroelectric material is characterized in that it is poly (vinylidene-co-trifluoroethylene).

As another embodiment of the present invention, the polymer solution is characterized by using acetone and dimethylformamide as a solvent.

In another embodiment of the present invention, the solvent is characterized in that acetone and dimethylformamide are mixed in a volume ratio of 2: 1.

As another embodiment of the present invention, the roller is characterized in that it is rotated at 4000rpm or more.

As another embodiment of the present invention, the voltage applied in step S3 is 25 kV or more.

In addition, the present invention provides a nanofiber produced by the above manufacturing method, and provides a filter comprising the nanofiber.

In addition, the present invention in the aligned nanofiber manufacturing apparatus,

A syringe unit for electrospinning the polymer solution;

A voltage supply unit connected to apply a voltage to the syringe unit; And

It is connected to the voltage supply unit, a roller installed in a direction orthogonal to the syringe unit; including, provides an aligned nanofiber manufacturing apparatus.

The nanofibers produced by the manufacturing method according to the present invention have an aligned shape and are characterized by an increased strength, and the electrical dipoles are aligned inside the fibers through a polarization effect including a ferroelectric material, and the aligned electrical dipoles are maintained as they are. , When manufactured as a filter using the nanofiber, there is an advantage that can increase the efficiency of the filter while maintaining the existing performance such as pressure difference or material properties.

1 shows an apparatus for manufacturing nanofibers of the present invention.
FIG. 2 is a diagram schematically showing a method of aligning electric dipoles inside nanofibers using a polarization effect in the present invention.
3 is a view showing a comparison of the unsorted nanofibers and the aligned nanofibers prepared in the present invention.
4 is a view showing the results of confirming the fine dust removal efficiency of the filter prepared using the unsorted nanofibers and the aligned nanofibers prepared in the present invention.

The present inventors have researched to develop a material for manufacturing a filter having an increased efficiency for removing fine dust, and as a result, when the polymer solution containing ferroelectric is electrospinned to produce nanofibers in an aligned form and used in the filter, the performance of the filter By confirming that it can be improved, the present invention was completed.

Accordingly, the present invention provides a method of manufacturing aligned nanofibers comprising the following steps:

Preparing a polymer solution containing a ferroelectric (S1);

Preparing the electrospinning by putting the polymer solution in a syringe (S2);

Electrospinning the polymer solution in a rotating roller direction by applying a voltage to the syringe (S3); And

Obtaining nanofibers deposited on the roller.

Hereinafter, the manufacturing method of the present invention will be described in more detail.

[Step S1]

In the present invention, step S1 is a step of preparing a polymer solution to be used for spinning. The polymer solution includes a ferroelectric material, and the ferroelectric material may be poly (vinylidene co-trifluoroethylene), which may be aligned through a polarization effect in the polymer solution. If the ferroelectric is not limited thereto, it is preferable to use the poly (vinylidene fluoride-co-trifluoroethylene) as in the embodiment of the present invention. The poly (vinylidene fluoride-co-trifluoroethylene) Silver trifluoroethylene and vinylidene fluoride are copolymerized copolymers, and the trifluoroethylene and vinylidene fluoride may be mixed in a molar ratio of 10 to 40:60 to 90, preferably 30:70 The poly (vinylidene fluoride-co-trifluoroethylene) preferably has a weight average molecular weight of 300,000 to 600,000.

A polymer solution in which the ferroelectric material is dissolved in a solvent is used, and the solvent may include acetone and dimethylformamide. The solvent is preferably acetone and dimethylformamide mixed in a volume ratio of 2: 1.

[Step S2]

In the present invention, step S2 is a step in which a polymer solution is placed in a syringe to prepare electrospinning. The shape of the syringe is not limited, but it is preferable to use a nozzle having a diameter of 20 to 30 gauge.

[Step S3]

In the present invention, step S3 is a step of electrospinning the polymer solution in the roller direction. The electrospinning is performed in a rotating state by driving the roller before the electrospinning, and the roller is preferably rotated at 4000 rpm to 100,000 rpm. If the rotation speed is less than 4000rpm, the nanofibers may not be properly aligned. Electrospinning is performed by supplying a voltage of 25 kV to 100 kV to a voltage supply unit connected to the syringe. When the voltage is less than 25 kV, an aligned shape is not formed. The discharge rate of the polymer solution is preferably performed at a rate of 1 ml / hour to 5 ml / hour, and more preferably 2.5 ml / hour to 3.5 ml / hour.

The roller is installed in a direction orthogonal to the syringe, and when electrospinning is started, a polymer solution is spun on the roller to deposit nanofibers. The roller is made of a metal material, and is not limited to the material as long as it is a material capable of depositing nanofibers.

[Step S4]

In the present invention, step S5 is a step of obtaining nanofibers deposited on a roller. The nanofibers may have an aligned shape as shown in FIG. 2.

In addition, the present invention can provide a filter comprising the nanofibers and the nanofibers produced by the above manufacturing method. The method of manufacturing a filter using the nanofibers is manufactured using a conventional filter manufacturing method.

In addition, the present invention can provide an aligned nanofiber manufacturing apparatus, as shown in FIG. 1. The nanofiber manufacturing apparatus includes the following components.

A syringe unit for electrospinning the polymer solution;

A voltage supply unit connected to apply a voltage to the syringe unit; And

A roller connected to the voltage supply part and installed in a direction orthogonal to the syringe part.

The nanofiber manufacturing apparatus includes a syringe unit; Voltage supply; And in addition to the roller, it may further include an element necessary for the production of nanofibers.

Hereinafter, preferred embodiments are provided to help understanding of the present invention. However, the following examples are only provided to more easily understand the present invention, and the contents of the present invention are not limited by the examples.

Example 1. Preparation of aligned nanofibers

Nanofibers were prepared according to the method shown in FIG. 1. As shown in FIG. 1, an electrospinning apparatus equipped with a syringe pump and a roller through which nanofibers are radiated was prepared.

As a discharge solution for nanofibers spun from the syringe pump, poly (vinylidene fluoride-co-trifluoroethylene) (PIEZOTECH, FC 30, 50 g, weight average molecular weight: 500,000 g / mol) is used as a polymer. , Acetone and dimethylformamide were used as a discharge solution using a polymer solution prepared using a solvent mixed in a volume ratio of 2: 1. At this time, the size of the nozzle used was a 23 gauge diameter with an inner diameter of 0.33 mm and an outer diameter of 0.63 mm. The discharge rate of the polymer solution was fixed at 3.0 ml / hour, and electrospinning was performed at a voltage of 25 kV. In addition, an aluminum thin film was used as the integrated plate. The nanofiber was manufactured by rotating the roller at 4000 RPM while discharging the polymer solution.

In the manufacturing process as described above, the ferroelectric is included in the polymer solution, so that the prepared ferroelectric nanofibers after electrospinning are placed under a strong electric field for at least 6 hours to align the electrical dipoles inside the material through the polarization effect as shown in FIG. 2.

Comparative Example 1. Preparation of nanofibers in general form

The nanofibers were prepared in the same manner as in Example 1, but the nanofibers were prepared by discharging the polymer solution into a flat vertical integrated plate instead of a rotating roller. Under the same method or condition as above, in the vertical production, the discharge rate was 0.4 ml / hour and electrospinning was performed at 12 kV.

Experimental Example 1. Confirmation of nanofiber morphology

The morphology of nanofibers prepared in Example 1 and Comparative Example 1 was confirmed using a long-high resolution scanning electron microscope (S-4800, Hitachi).

As shown in FIG. 3, the nanofibers produced in Comparative Example 1 were made of non-aligned nanofibers, but it was confirmed that the nanofibers prepared in Example 1 had an aligned shape. From the above results, when the nanofibers were prepared by the method of the present invention, it had an aligned shape, confirming that the strength of the fibers was strong.

Experimental Example 2. Filter efficiency check

In order to measure the removal efficiency of the nanofibers prepared in Example 1 and Comparative Example 1, a potassium chloride solution having a concentration of 1 wt% based on 100 mL was prepared using DI water as a solvent to generate particles. The particles were created with an atomizer in the prepared solution to confirm that the particles were well formed, and the particle counter was inserted to measure the efficiency by inserting nanofibers. The size of the nanofibers was measured by fixing them at 4 cm * 4 cm.

For efficiency measurement, the efficiency was calculated from the particle concentration and number difference between the front and rear ends after measuring up to 3 minutes. The wind speed condition was fixed at a flow rate of 2 m ³ / h, and was measured to be fixed at 0.35 m / s in terms of plane speed. After adjusting the flow rate, the pressure difference between the front and rear ends was also tracked and recorded.

The results are shown in FIG. 4, and as shown in FIG. 4, it was confirmed that the nanofibers prepared by using the polarization effect in Example 1 had a removal efficiency of 90% or more, compared with the nanofibers of Comparative Example 1 It was confirmed that there is an excellent removal effect.

From this, it was confirmed that the nanofibers produced by the method of the present invention can be used as a material for a filter. In addition, from the above results, it was confirmed that the filter using nanofibers produced by the method of the present invention can also remove fine dust of 1.0 μm or less, and it was found that a great effect can be seen even at PM 1.0 smaller than PM 2.5.

The above description of the present invention is for illustration only, and those skilled in the art to which the present invention pertains can understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (9)

A method of manufacturing an aligned nanofiber comprising the following steps:
Preparing a polymer solution containing a ferroelectric (S1);
Preparing the electrospinning by putting the polymer solution in a syringe (S2);
Electrospinning the polymer solution in a rotating roller direction by applying a voltage to the syringe (S3); And
And obtaining the nanofibers deposited on the roller (S4),
The ferroelectric includes poly (vinylidene fluoride-co-trifluoroethylene), and the poly (vinylidene fluoride-co-trifluoroethylene) has 10 to 40 trifluoroethylene and vinylidene fluoride. : It is mixed at a molar ratio of 60 to 90, and the solvent of the polymer solution is acetone and dimethylformamide mixed at a volume ratio of 2: 1,
The roller is rotated at a speed of 4000rpm to 100,000rpm,
The polymer solution is to be discharged at a rate of 1 ml / hour or more and less than 3 ml / hour, the method of manufacturing aligned nanofibers.
delete delete delete delete delete Nanofibers prepared by the method of claim 1.
A filter comprising the nanofiber of claim 7.
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