KR102153380B1 - Manufacturing method of fine dust filter - Google Patents

Abstract

The present invention relates to an electrically oriented filter for blocking fine dust produced including a filter manufacturing step of forming a nanofiber web by electrospinning a fluorine-based polymer solution on a substrate, and a dipole reinforcing step of strengthening the dipole by applying an electric field to the filter. It relates to manufacturing methods, filters and kits.

Description

Filter manufacturing method for blocking fine dust {MANUFACTURING METHOD OF FINE DUST FILTER}

The present invention relates to a filter for collecting fine dust contained in air introduced into the room from the outside, including a nanofiber web, and more particularly, a filter with improved collection efficiency by reinforcing the size of a dipole by applying an electric field to the filter, and It relates to a manufacturing method.

The dust floating in the air is divided into TSP (Total Suspended Particles) and fine dust (PM, Particulate Matter) having a particle size of 50 µm or less. Of these, fine dust is again fine with a diameter of 10 µm or less (PM 10). It is classified into dust and ultrafine dust with a diameter of 2.5 ㎛ or less (PM 2.5).

In addition, fine dust is generated in the process of burning fossil fuels such as factory fumes and automobile exhaust gases, and is mainly composed of harmful substances such as sulfate, nitrate, ammonia and heavy metals. When breathing through the nose, large dusts in the nose are filtered through the hair or by mucus in the nose and throat, but ultrafine dust is not filtered and penetrates into the body, causing various respiratory and cardiovascular diseases.

Accordingly, the importance of a filter device for purifying contaminated air is increasing, and various filter devices are continuously being developed in order to increase the filtering function and efficiency of the filter device. Among them, nanofibers are used as a material for filters as a material that exhibits high performance throughout the industry.

In the electrospinning technology used for nanofibers to collect fine dust, a high voltage is applied to a polymer solution or melt, and the polymer solution is sprayed onto the surface charged with a negative (-) pole or an earth. As the solvent volatilizes during this process, nanofibrous materials are laminated in a web or non-woven state on a collector to produce nanofibers. These nanofibers are manufactured in the form of a web or nonwoven fabric by controlling porosity and pore size according to the diameter and thickness of the fiber. However, the nanofiber web has a problem in that the dipole orientations of the polymers constituting the interior are different and cancel each other, and thus, the size of the dipoles of the entire nanofibers decreases, so that fine dust cannot be effectively collected. In addition, it is difficult to remove the collected dust from the filter, thereby increasing the consumption of the filter and making it difficult to reuse.

The present invention was conceived to solve the above problems, and an object of the present invention is to provide a filter for blocking fine dust with a remarkably improved particle collection efficiency by significantly increasing the size of the dipole inside the nanofiber, and a method and a kit for manufacturing the same. do.

In addition, an object of the present invention is to provide a filter for blocking fine dust that can ensure sufficient visibility during the day.

In addition, it is an object of the present invention to provide a filter for blocking fine dust having excellent ventilation when used as a filter because even though fine dust accumulates, air permeability is relatively high during long-term use.

One aspect of the present invention for achieving the above object

A filter manufacturing step of electrospinning a fluorine-based polymer solution on a substrate to form a nanofiber web, and

It is a method of manufacturing an electrically oriented filter for blocking fine dust, which is manufactured including a dipole strengthening step of strengthening a dipole by applying an electric field to the filter.

In one aspect of the present invention, the dipole strengthening step may be that the electric field is 50 to 300 kV/cm.

In one aspect of the present invention, after the filter manufacturing step, a lamination step of compressing the nanofiber web applied on the substrate may be further included.

In one aspect of the present invention, the fluorine-based polymer is vinylidene fluoride, vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, trifluoroethylene, hexafluoroisobutylene, purple It may be a homopolymer including a monomer selected from luoro butylethylene, perfluoro methyl vinyl ether, perfluoro ethyl vinyl ether and perfluoro propyl vinyl ether, or a copolymer thereof.

In an aspect of the present invention, the electrospinning may have a tip to collector distance (TCD) of 10 to 30 cm, a scanning speed of 5 to 30 mL/hr, and a spinning time of 50 to 600 seconds.

In the present specification, TCD means a radiation distance from a nozzle tip to a substrate.

Another aspect of the present invention is a substrate; And it may be a filter for blocking fine dust comprising an electrically oriented fluorine-based polymer nanofiber web formed on the substrate.

In another aspect of the present invention, the filter for blocking fine dust may have a surface voltage of 3kV to 4.5kV.

In another aspect of the present invention, the nanofiber web may have a thickness of 1 to 50 μm.

In another aspect of the present invention, the nanofiber web has a light transmittance of 75% or more of a filter measured at 600 nm when electrospinning under conditions of a TCD of 11 cm, a scanning speed of 20 mL/hr, and a spinning time of 120 seconds. I can.

In another aspect of the present invention, the filter may have a fine dust collection efficiency of 80% or more according to the weight method of ASHRAE STANDARD 52.1.

In another aspect of the present invention, the nanofiber may have a diameter of 10 to 500 nm.

Another aspect of the present invention may be a filter kit for blocking fine dust formed by stacking any one of the filters for blocking fine dust.

In another aspect of the present invention, the laminate may be formed to be spaced apart from each other.

In another aspect of the present invention, electrodes are formed on both end layers of the filter, and an additional electric field is applied to increase the surface voltage.

The present invention can provide a filter for blocking fine dust with remarkably improved fine dust collection efficiency by remarkably increasing the size of a dipole inside a nanofiber, and a method and a kit for manufacturing the same.

In addition, the filter of the present invention has the advantage of ensuring sufficient visibility during the day.

In addition, the present invention maintains relatively high air permeability during long-term use even when fine dust accumulates, and thus has an advantage of excellent ventilation when used as a filter.

In addition, the present invention has the advantage of being able to use for a long period of high reusability by efficiently removing collected fine dust in a short time.

1 is a scanning electron microscope (SEM) photograph of a nanofiber web prepared in Examples 1 to 3 of the present invention.
2 is a graph showing the surface voltage in Example 1 and Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail through specific examples or examples including the accompanying drawings. However, the following specific examples or examples are only one reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

In addition, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. The terms used in the description in the present invention are merely intended to effectively describe specific embodiments and are not intended to limit the present invention.

In addition, the singular form used in the specification and the appended claims may be intended to include the plural form unless otherwise indicated in the context.

In the present invention, the basis weight (Basis Weight of Grammage) is defined as mass per unit area, that is, grams per square meter as a preferred unit (g/m ² ).

The inventors of the present invention have found that in providing a filter for blocking fine dust, ventilation is excellent, visibility is ensured, and can effectively block fine dust during long-term use.

In addition, the manufactured filter for blocking fine dust has been found to have high reusability since it can effectively remove the collected fine dust, thereby completing the present invention.

Hereinafter, a method of manufacturing a filter for blocking fine dust according to the present invention, a filter and a kit for blocking fine dust manufactured through the method of the present invention will be described in more detail.

The method of manufacturing a filter for blocking fine dust according to the present invention

A filter manufacturing step of forming a nanofiber web by electrospinning a fluorine-based polymer solution on a substrate, and a dipole reinforcement step of reinforcing a dipole by applying an electric field to the filter.

In one aspect of the present invention, a nanofiber web is formed by electrospinning a fluorine-based polymer solution on a substrate. The fluorine-based polymer has excellent chemical resistance, high durability, and strong dipole formation when a nanofiber web is prepared from a solution and an electric field is applied, which is remarkably advantageous in collecting dust.

The substrate is used as a support or mounting sheet on the collector during electrospinning. In addition, the physical properties of the nanofiber web can be supplemented and handling properties can be improved. The substrate is not particularly limited as long as the nanofiber web can be formed thereon, but may be a porous substrate or a mesh.

The form of the porous substrate may be selected from a microporous film, a nonwoven fabric, and a woven fabric, and the material of the porous substrate may be selected from a polyester series, a nylon series, a polyolefin series, and a cellulose series. In addition, the mesh may be a polyolefin-based mesh, a polyester mesh, a fiberglass mesh, a nylon mesh, a steel mesh, and an aluminum mesh.

The polyolefin may be polyethylene or polypropylene, but is not limited thereto.

The basis weight of the substrate may be 5 to 100 g/m ² , and when the above range is satisfied, the physical properties of the filter support are satisfied, and the stiffness is good and the workability may be good. Preferably it may be 10 to 50 g/m ² , more preferably 15 to 40 g/m ² .

In addition, the basis weight of the nanofiber web may be 0.5 to 10 g/m ² , and when the above range is satisfied, a nanofiber web and a filter may be manufactured with a small amount of polymer, and mechanical properties may be excellent and breathability may be good. . Preferably it may be 0.5 to 5 g/m ² , and more preferably 0.5 to 2 g/m ² .

In one aspect of the present invention, the fluorine-based polymer is vinylidene fluoride, vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, trifluoroethylene, hexafluoroisobutylene, perfluoro It may be a homopolymer or a copolymer thereof comprising a monomer selected from butylethylene, perfluoro methyl vinyl ether, perfluoro ethyl vinyl ether and perfluoro propyl vinyl ether, preferably vinylidene fluoride and tri It may be a copolymer of fluoroethylene, but is not limited thereto. The fluorine-based polymer may be dissolved in an organic solvent for electrospinning, and examples of the organic solvent include acetone, N-methyl-2-pyrrolidone (NMP), and dimethylformamide (DMF). ), chloroform (chloroform), dimethyl sulfoxide (dimethylsulfoxide) and dimethylacetamide (dimethylacetamide, DMAc) may be a mixture of one or two or more selected from, but is not limited thereto, preferably acetone and dimethylformamide.

The polymer solution is spun by an electrospinning process. The electrospinning process refers to a process capable of manufacturing nanofibers through a jet of an electrically charged polymer solution and melt. The manufacturing method using the electrospinning includes an electric field forming unit comprising an anode, a cathode provided spaced apart from the anode, and a power supply device coupled to the anode and the cathode, and formed between the anode and the cathode by the electric field forming unit. It is possible to use a manufacturing apparatus including a nozzle for spinning the polymer solution in the electric field forming space.

In addition, the nanofiber web can be obtained by forming and stretching a jet by the electric field. The nanofiber web is homogeneous, and the smaller the diameter is, the better it is to collect particles having a smaller particle diameter, and thus is suitable as a filter.

In one aspect of the present invention, TCD (Tip to collector distance), which means the spinning distance from the nozzle tip to the substrate, may be 10 to 30 cm, and the spinning time may be 50 to 600 seconds. When the TCD and spinning time are satisfied, a nanofiber web that is uniform and has good air permeability can be formed. Preferably, the TCD may be 10 to 25 cm, the spinning time may be 70 to 500 seconds, more preferably the TCD may be 10 to 15 cm, and the spinning time may be 90 to 500 seconds, but are not limited thereto.

In addition, when performing the electrospinning, the scanning speed of the spinning solution may be 5 to 30 mL/hr. When the scanning speed is as described above, the spinning solution is continuously discharged, and nanofibers of uniform size can be formed, and the spinning solution is well collected in the collector, thereby improving the productivity of the nanofiber web. Preferably, it may be 10 to 25 mL/hr, more preferably 15 to 23 mL/hr.

In one aspect of the present invention, the spinning temperature may be 5 to 45 °C in terms of uniform nanofiber web production, and when the above range is satisfied, the solvent is volatilized to form nanofibers, and thus the strength of the prepared nanofiber web Can increase. Preferably, it may be 10 to 35 °C, more preferably 15 to 35 °C.

The content of the fluorine-based polymer in the polymer solution may be 0.1 to 0.5 g, preferably 0.2 to 0.4 g, more preferably 0.25 to 0.35 g per 2.5 mL of the solvent in terms of preventing the formation of particles and beads. have.

When performing the electrospinning, the applied voltage may be 5 to 40 kV. When the above range is satisfied, spinning of the spinning solution is smooth and uniformity of the nanofibers is improved. It may be preferably 5 to 20 kV, more preferably 10 to 13 kV.

In one aspect of the present invention, a dipole strengthening step of strengthening the dipole by applying an electric field to the filter is included. When the fluorine-based polymer solution is electrospun, dipoles between the fluorine-based polymers may be canceled and the dipoles of the entire nanofiber web may be reduced or absent. Therefore, it was found that fine dust can be effectively collected when dipoles are formed in one direction inside the nanofiber web by passing an external electric field through the filter.

In addition, in the dipole reinforcing step, an electric field is passed through the substrate and the nanofiber web so that an electric field is formed between the electrodes, so that each nanofiber is uniformly arranged along the electric field.

In one aspect of the present invention, the electric field in the dipole reinforcing step may be 50 to 300 kV/cm, and the surface voltage is increased due to the uniform arrangement of nanofibers and the improvement of the dipole size of the entire nanofiber web within the above range. can do. Preferably it may be 50 to 200 kV/cm, more preferably 50 to 150 kV/cm. However, the strength of the electric field is not limited as long as the dipole can be induced.

In one aspect of the present invention, after the filter manufacturing step, the Na applied on the substrate

It may further include a lamination step of compressing the fiber web.

When performing the lamination step, by compressing the nanofiber web to the substrate, it is preferable to prevent detachment and damage of the nanofiber web from the substrate. The temperature of the lamination step is not particularly limited as long as it is higher than the softening point of the surface of the substrate or the nanofiber web. As a non-limiting example, in the case of a polyester substrate, when the filter is laminated at 200°C, it is good to be fixed without damaging the nanofibers.

The lamination method may include a roll to roll method, a direct coating method, a printing method, and a screen method, but preferably a roll to roll method.

Another aspect of the present invention is a substrate; And an electrically oriented fluorine-based polymer nanofiber web formed on the substrate, wherein the surface voltage of the filter for blocking fine dust may be 3kV to 4.5kV, but is not limited in a range in which electrical orientation is possible. . In the case of electrical orientation, the electrostatic attraction between the fine dust and the nanofiber web increases, so that particle removal efficiency is greatly improved, and the differential pressure due to air resistance does not increase.

In one aspect of the present invention, the thickness of the nanofiber web may be 1 to 50 μm. The thickness of the nanofiber web is determined by ASTM D1777-64, and the unit is expressed in'㎛'. When the above range is satisfied, breathability and visibility increase. It may be preferably 5 to 35 ㎛, more preferably 5 to 30 ㎛, but is not limited thereto.

In one aspect of the present invention, the nanofiber web may have a light transmittance of 75% or more measured at 600 nm when electrospinning under conditions of a TCD of 11 cm, a scanning speed of 20 mL/hr, and a spinning time of 120 seconds. If the above range is satisfied, an outdoor view can be optimally secured when applied to a window. It may be preferably 75 to 98%, more preferably 78 to 85%.

In one aspect of the present invention, the filter may have a fine dust collection efficiency of 80% or more according to the weight method of ASHRAE STANDARD 52.1.

When the above range is satisfied, since the nanofiber web has a large specific surface area and a small pore size, not only fine dust but also ultrafine dust can be collected with high efficiency, and thus it may be suitable for application as a filter. Preferably it may be 85 to 100%, more preferably may be 90 to 100%.

In one aspect of the present invention, the nanofibers may have a diameter of 10 to 500 nm. When the above range is satisfied, it has a high specific surface area and can form fine pores, and thus it can be effective for collecting fine dust. It may be preferably 50 to 300 nm, more preferably 50 to 200 nm.

In the filter for blocking fine dust, the base material and the fluorine-based polymer are the same as those described in the manufacturing method, and redundant descriptions are omitted.

Another aspect of the present invention is a kit, which is formed by laminating the filter for blocking fine dust. When the filter is formed by stacking it, a large filter can be manufactured, so that the collecting efficiency of fine dust can be further improved.

In the kit, the filter stacks for blocking fine dust may be formed by being spaced apart from each other by a certain distance, and pressure loss may be reduced when formed by being spaced apart. The separation distance is not limited as long as it is a value capable of maximizing fine dust collection efficiency, but may be 10 to 20 mm, and preferably 11 to 13 mm.

In one aspect of the present invention, the filter kit may have an increased surface voltage by forming electrodes on both end layers and applying an additional electric field.

In the step of raising the surface voltage, a plurality of electrodes are installed in the axial direction on both sides of the filter kit, and an electric field is formed between the electrodes by applying a voltage to the electrodes, thereby increasing the surface voltage. When a filter having a surface voltage of 3kV to 4.5kV is stacked, the surface voltage of the filter kit may be 5kV to 10kV, preferably 5kV to 8kV, more preferably 5kV to 7kV. By increasing the surface voltage of the filter kit, the fine dust collection performance can be excellent, and when a reverse voltage is applied, the collected fine dust can be easily removed, so that reusability can be excellent.

The application of the filter and filter kit is not limited, but may be applied to a window, a mask, a helmet, an automobile air conditioning system, an industrial exhaust filtration system, and the like, preferably a window and a mask.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following Examples and Comparative Examples are only one example for describing the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Method of measuring physical properties]

1) Light transmittance measurement

According to ASTM E 424-71 (2007, METHOD A 6. 5. 2 SELECTED ORDINATES METHOD), light transmittance at 600 nm was measured using a UV-Vis spectrometer.

2) Measurement of fine dust collection efficiency

1% by weight of potassium chloride was dissolved in distilled water and a particle generator was operated to prepare particles having an average particle diameter of 2.5 µm. The particles were injected into nanofibers to measure the capture efficiency of potassium chloride at a test wind speed of 1.0 m/s and an end pressure loss of 76 mmAq according to the gravimetric method of ASHRAE STANDARD 52.1.

3) Measurement of filter surface voltage

The surface voltage was measured using an electrostatic measurement surface potentiometer model 344 (TREK Inc, Electrostatie voltmeter model 344).

[Example 1]

Put 0.341 g of PVDF-TrFE (poly(vinylidene fluoride-trifluoroethylene)) (manufactured by Poly K) powder into a container containing 1.5 mL of DMF (dimethylformamide) and 1 mL of acetone solution, and dissolve at 50°C for 3 hours to dissolve the polymer solution. Was prepared.

After that, after moving the polymer spinning solution to the nozzle block, the TCD (Tip to collector distance) is 11cm at 25℃, the scanning speed is 20mL/hr, the applied voltage is 12 kV, and the polyester mesh used as the base material (16 mesh, Basis weight: 27.36 g/m ² , density: 25×25 pieces/inch) were electrospun for 120 seconds.

Subsequently, the prepared substrate and the nanofiber web were passed through an electric field of 100 kV/cm and laminated at 200° C. by a roll-to-roll technique to compress the nanofiber web on the substrate.

[Example 2]

It was prepared in the same manner as in Example 1 except for electrospinning for 240 seconds.

[Example 3]

It was prepared in the same manner as in Example 1 except for electrospinning for 480 seconds.

[Comparative Example 1]

It was prepared in the same manner as in Example 1, except that an electric field was not passed through the nanofiber web.

[Comparative Example 2]

It was prepared in the same manner as in Example 2 except that the electric field was not passed through the nanofiber web.

[Comparative Example 3]

It was prepared in the same manner as in Example 3, except that an electric field was not passed through the nanofiber web.

In Example 1, as a result of producing a nanofiber web and a filter by electrospinning for 120 seconds, it exhibited a light transmittance of 80% at 600 nm and a fine dust collection efficiency of 90.5% due to a high surface voltage. In addition, in Example 2, a nanofiber web and a filter were prepared by electrospinning for 240 seconds, and exhibited a light transmittance of 60% and a fine dust collection efficiency of 95.6% at 600 nm. In addition, in Example 3, a nanofiber web and filter were prepared by electrospinning for 480 seconds, exhibiting a light transmittance of 40% at 600 nm, and a fine dust collection efficiency of 97.1%.

Therefore, it was confirmed that as the electrospinning time increased, the fine dust collection efficiency increased due to the small pore size of the nanofiber web. In addition, in all of Examples 1 to 3, the surface voltage was as high as 4 or more as the electric field was applied, and thus, the fine dust collection efficiency was high. In addition, it was confirmed that even when fine dust was accumulated, air permeability was excellent and visibility was sufficiently secured during long-term use.

In Comparative Examples 1 to 3, a low surface voltage was formed because an electric field was not passed through the nanofiber web, and a low fine dust collection efficiency was shown.

Therefore, it was confirmed that improved fine dust collection efficiency, high air permeability and visibility during long-term use were secured when an electric field was applied as in the Example.

As described above, the present invention has been described by a limited embodiment, but this is provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiment, and common knowledge in the field to which the present invention pertains. Anyone who has it can make various modifications and variations from these substrates.

Therefore, the spirit of the present invention is limited to the described embodiments and should not be defined, and all things that are equivalent or equivalent to the claims as well as the claims to be described later fall within the scope of the spirit of the present invention. .

Claims (15)

A filter manufacturing step of electrospinning a fluorine-based polymer solution on a substrate to form a nanofiber web, and
A method of manufacturing an electrically oriented fine dust blocking filter having a surface voltage of 3kV to 4.5kV, including a dipole strengthening step of strengthening a dipole by applying an electric field to the filter. The method of claim 1,
The dipole reinforcing step is a method of manufacturing a filter for blocking fine dust having an electric field of 50 to 300 kV/cm. The method of claim 1,
After the filter manufacturing step, a method of manufacturing a filter for blocking fine dust, further comprising a lamination step of compressing the nanofiber web applied on the substrate. The method of claim 1,
The fluorine-based polymer is vinylidene fluoride, vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, trifluoroethylene, hexafluoroisobutylene, perfluoro butylethylene, perfluoro A method for producing a filter for blocking fine dust, which is a homopolymer or a copolymer thereof comprising a monomer selected from methyl vinyl ether and perfluoro ethyl vinyl ether and perfluoro propyl vinyl ether. The method of claim 1,
The electrospinning method of manufacturing a filter for blocking fine dust having a TCD of 10 to 30 cm, a scanning speed of 5 to 30 mL/hr, and a spinning time of 50 to 600 seconds. materials; And
Filter for blocking fine dust comprising an electrically oriented fluorine-based polymer nanofiber web having a surface voltage of 3kV to 4.5kV formed on the substrate. delete The method of claim 6,
The nanofiber web is a filter for blocking fine dust having a thickness of 1 to 50 μm. The method of claim 6,
The nanofiber web is a filter for blocking fine dust having a light transmittance of 75% or more of the filter measured at 600 nm when electrospinning under conditions of a TCD of 11 cm, a scanning speed of 20 mL/hr and a spinning time of 120 seconds. The method of claim 6,
The filter is a filter for blocking fine dust having an efficiency of collecting fine dust of 80% or more according to the weight method of ASHRAE STANDARD 52.1. The method of claim 6,
The fluorine-based polymer is vinylidene fluoride, vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, trifluoroethylene, hexafluoroisobutylene, perfluoro butylethylene, perfluoro A filter for blocking fine dust, which is a homopolymer or a copolymer thereof containing a monomer selected from methyl vinyl ether, perfluoro ethyl vinyl ether and perfluoro propyl vinyl ether. The method of claim 6,
The nanofiber is a filter for blocking fine dust having a diameter of 10 to 500 nm. A filter kit for blocking fine dust formed by stacking any one of the fine dust blocking filters selected from claims 6 and 8 to 12. The method of claim 13,
The laminate is a filter kit for blocking fine dust formed by being spaced apart from each other. The method of claim 13,
A filter kit for blocking fine dust in which an electrode is formed on both end layers of the filter and a surface voltage is increased by applying an additional electric field.

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