KR20140121185A - Fabrication system of CNT filter using electro-aerodynamic jet printing, method for fabricating the same, and CNT filter manufactured with said method - Google Patents

Abstract

The present invention provides a fabrication system of a CNT filter using electro-aerodynamic jet printing, a fabrication method thereof, and a CNT filter manufactured thereby. The fabrication system of a CNT filter using electro-aerodynamic jet printing is able to conveniently and rapidly perform a fabrication process when compared to a CNT filter manufacture using a conventional chemical vapor deposition (CVD), and to prevent a durability degradation of the filter as the entire fabrication processes are performed at room temperature and normal pressure. The fabrication system of a CNT filter of the present invention comprises: a compressed air supply device to supply compressed air carrying CNT particles; a vaporizing device to flow in the compressed air supplied from the compressed air supply device, and spraying a CNT solution including the CNT particles to vaporize into a CNT gas form; a drying device to remove moisture contained in the CNT gas vaporized through the vaporizing device; a charging device to charge the CNT particles with moisture removed through the drying device to a specific polarity; and a jet nozzle to spray CNT particles onto a filter placed on an electrode substrate applied with a voltage of a polarity opposite to the polarity of the charged CNT particles in a jet flow form to vertically align and print the CNT particles on a textile substrate of a filter by the electric field.

Description

Technical Field [0001] The present invention relates to a CNT filter manufacturing system and an CNT filter manufacturing method using an electro-aerodynamic jet printing technique, and a CNT filter fabricated by the CNT filter manufacturing method said method}

The present invention relates to a system for manufacturing a CNT filter used in various antibacterial and deodorizing filters, and more particularly, to a CNT filter manufacturing method that can be manufactured more simply and quickly than a CNT filter manufacturing process using a conventional chemical vapor deposition A CNT filter manufacturing system using an electronically-assisted jet printing technique capable of preventing the durability of a filter from being deteriorated due to a conventional high-temperature heat treatment operation because all the processes for manufacturing the CNT filter are performed under normal temperature and normal pressure conditions, And a CNT filter manufactured by a manufacturing method.

Indoor air is flooded with various microorganisms such as bacteria, fungi, and viruses, and these floating microorganisms cause air infections and environmental diseases, which adversely affect health. Such indoor floating microorganisms can be filtered by a filter for primarily removing dust, but there is a problem that the microorganisms multiply on the surface of the filter substrate due to the life property of microorganisms and then flow into the room again.

In order to cope with such a problem, an inorganic antibacterial agent such as silver (Ag), copper (Cu), gold (Au), and TiO2 or an organic antimicrobial agent such as cadecin, chitosan, phytoncide, ginkgo leaf extract, herb extract, Is applied to the surface of a filter substrate having a mesh structure to prevent the growth of microorganisms.

However, most of these techniques require a large amount of antimicrobial agent because the antibacterial agent is applied to the surface of the filter substrate through the process of making the inorganic or organic antimicrobial agent into a liquid phase, then immersing and removing the filter substrate therein There is a disadvantage that the antibacterial substance is unevenly adhered to the surface of the filter substrate and a drying process is additionally required.

On the other hand, recently, a CNT (carbon nano tube) material having a large aspect ratio and a specific surface area is attracting attention as a new filter material. These CNTs are widely applied to various antibacterial and deodorizing filter systems because they have excellent electrical conductivity and excellent antibacterial and deodorizing power.

The conventional method of manufacturing the antibacterial deodorization filter using CNT is such that CNT seed particles are first deposited on a filter and CNT seed particles are deposited on a filter into a CVD (Chemical Vapor Deposition) chamber. And a CNT filter is produced. The CNT filter manufacturing method using such a CVD process has been described in detail in Korean Patent Laid-Open Publication No. 2009-0090773.

However, in the conventional CNT filter manufacturing method described above, since a filter having CNT seed particles deposited therein is placed in a CVD chamber and CNTs are grown, high temperature heat of about 650 to 1000 ° C must be supplied together with the catalyst, There has been a problem that the durability of the filter is remarkably lowered due to the influence of such high temperature. In addition, the conventional CNT filter manufacturing method using the CVD process has a problem that the manufacturing process of the filter is very complicated and the production of the filter takes a long time longer than 3 hours

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above problems, and an object of the present invention is to provide a CNT solution in which a CNT solution in which CNT particles are dispersed is vaporized in a droplet state through a vaporizer, And the CNT particles are vertically adhered and aligned on the fiber substrate of the filter by the electric field generated by applying a voltage of the opposite polarity to the charged electric charge on the electrode substrate on which the filter is mounted, CNT filter manufacturing system using electro-aerofoil jet printing technique which can increase the durability of filter by coating CNT particles directly on the filter through simple process without heat treatment process and can shorten filter manufacturing time and improve productivity And a manufacturing method thereof.

According to an aspect of the present invention, there is provided a system for manufacturing a CNT filter using an electro-aerodynamic jet printing technique, comprising: a compressed air supply device for supplying compressed air for transporting CNT particles; A vaporizer for introducing the compressed air supplied from the compressed air supply device and spraying a CNT solution containing CNT particles into a CNT gas; A drying device for removing water contained in the vaporized CNT gas via the vaporizer; A charging device for charging the CNT particles having moisture removed through the drying device to a specific polarity; The charged CNT particles are injected in a jet flow form by a filter placed on an electrode substrate to which a voltage of a polarity opposite to the polarity of the charged CNT particles is applied, And a spray nozzle for vertically aligning the nozzles.

Here, the injection nozzle may include: a first flow path having a linear shape into which the charged CNT particles flow; A second flow path formed concentrically with the first flow path and surrounding the first flow path, the second flow path forming part of the compressed air generated by the compressed air supply device to generate a sheath flow; And a nozzle hole through which the CNT particles injected through the first flow path are injected into the filter together with the sheath flow injected through the second flow path.

A flow meter capable of measuring a flow rate and a velocity of compressed air may be installed between the compressed air supply device and the vaporizer, and between the compressed air supply device and the spray nozzle.

Further, a soft X-ray generating device may be further provided between the drying device and the charging device to maintain the CNT particles in a charge neutral state.

According to another aspect of the present invention, there is provided a CNT filter manufacturing method using an electro-aerodynamic jet printing technique, comprising the steps of: (a) vaporizing a CNT solution containing CNT particles through a vaporizer to form CNT gas; ; (b) removing moisture contained in the vaporized CNT gas by using a drying device; (c) charging the water-removed CNT particles to have a specific polarity using a charging device; (d) injecting the charged CNT particles in a jet flow form through a filter on an electrode substrate to which a voltage of a polarity opposite to the polarity of the charged CNT particles is applied, And printing the particles by vertically aligning the particles on the fiber substrate of the filter.

At this time, a portion of the compressed air provided for transporting the CNT particles may be introduced into the injection nozzle to provide a sheath flow surrounding the CNT particles.

Between the steps (b) and (c), a CNT particle charge neutralization step may be performed to maintain the CNT particles in a state of charge neutral state through the removal of moisture through the step (b) can do.

According to the CNT filter manufacturing method using the electro-aerodynamic jet printing of the present invention, CNT solution containing CNT particles is vaporized, moisture is removed through a dryer, The CNT particles are vertically aligned and coated on the fiber substrate of the filter by an electric field generated by applying a voltage of the opposite polarity to the charged electric charge on the electrode substrate on which the filter is mounted, The CNT filter can be manufactured more simply and quickly than the conventional CVD process. In addition, unlike the conventional CVD process, CNT particles can be directly coated on the filter without the need for a high-temperature heat treatment process for CNT growth, and all processes are performed under normal temperature and pressure conditions. Thus, It is possible to prevent the durability of the filter from being degraded due to the shortage of the filter, and it is possible to shorten the production time of the filter, thereby greatly improving the productivity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a CNT filter manufacturing system using an electro-aerodynamic jet printing method according to the present invention. FIG.
FIG. 2 is a process chart sequentially showing a CNT filter manufacturing method according to the present invention. FIG.
3 is a SEM photograph of a CNT filter manufactured using the CNT filter manufacturing system of the present invention.
4 is a graph showing the coating efficiency of the CNT filter according to the present invention.
5 is a graph showing the results of the desorption evaluation of the CNT filter according to the present invention.
6 is a graph showing a result of measurement of differential pressure of the CNT filter according to the present invention.
7 is a graph showing the results of measuring the filter efficiency of the CNT filter according to the present invention.
FIG. 8 is a graph showing the collection efficiency and the prediction result according to the coating time by the virus collection experiment and the theoretical calculation by the CNT filter according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the entire construction of a CNT filter manufacturing system using an electro-aerodynamic jet printing method according to the present invention, and FIG. 2 is a process diagram sequentially showing a CNT filter manufacturing method according to the present invention.

Referring to FIG. 1, a CNT filter manufacturing system 100 using an electro-aerodynamic jet printing technique according to the present invention includes a compressed air supply device 110, a vaporizer 120, A flexible X-ray generator 140, a charging device 150, voltage application devices 152 and 182, an injection nozzle 160, a filter 170, and an electrode substrate 180.

The compressed air supply unit 110 generates a carrier gas for conveying CNT particles, that is, compressed air, and supplies the compressed air to the inside of the vaporizer 120. A part of the compressed air generated in the compressed air supply device 110 is supplied to the injection nozzle 160, which will be described later.

At this time, the compressed air supply device 110 is provided with a HEPA filter 112 for filtering the fine particle impurities contained in the compressed air, and also controls the pressure, flow rate, and speed of the compressed air A regulator 114 is provided.

The vaporizer 120 vaporizes the CNT solution in which the CNT particles are dispersed by spraying the CNT solution in the form of mist by applying a predetermined pressure to the CNT gas in the droplet state. Thereafter, the CNT gas vaporized in the droplet state flows into the drying apparatus 130 together with compressed air as a carrier gas.

At this time, a flow meter 116 is installed on the compressed air moving passage before entering the vaporizer 120 to measure the flow rate of the compressed air flowing into the vaporizer 120.

The drying apparatus 130 removes moisture contained in the vaporized CNT gas through the vaporizer 120 in a droplet state.

Here, as the drying device 130, a diffusion dryer may be used. In such a diffusion dryer, a replaceable drying agent capable of collecting droplets is incorporated. The desiccant removes moisture in the CNT gas that is moved along the flow of the compressed air using a diffusional capture method. This desiccant can minimize the particle loss of the CNT because it can remove moisture without contacting the CNT gas (aerosol).

The soft X-ray generator 140 turns the CNT particles into a charge neutral state before the CNT particles are introduced into the charging device 150.

That is, before the CNT particles are introduced into the charging device 150, it is necessary to make the CNT particles into a charge neutral state in order to accurately charge the CNT particles to a specific polarity. The soft X- 120) to a charged neutralized state having a Boltzmann charge distribution.

The charging device 150 charges the CNT particles in a state in which water is removed through the drying device 130 to a specific polarity (+ or -) to make the electric charge. In this embodiment, negative (-) voltage is applied to the charging device 150 through the voltage applying device 152 so that the CNT particles are charged with (-) polarity. The CNT particles charged through this charging process are intensively charged at both ends with a negative polarity.

The CNT particles charged through the charging device 150 are injected into the injection nozzle 160 and then sprayed onto the filter 170 mounted on the electrode substrate 180 to coat the CNT particles on the filter 170.

A voltage of positive polarity opposite to the polarity of the charged particles of the CNT particles is applied to the electrode substrate 180 on which the filter 170 is mounted through the voltage application device 182, The surface of the electrode substrate 180 on which the electrodes 170 are mounted is charged to the positive polarity.

When a voltage (+) opposite to the charged CNT particles is applied to the electrode substrate 180 in this manner, the nozzle hole 163 of the lower part of the injection nozzle 160, in which the CNT particles are emitted, And the CNT particles injected through the injection nozzle 160 are adhered in a state of being vertically aligned on the fiber substrate of the filter 170 by the thus formed electric field so that the filter 170 ) Is coated with CNT particles. At this time, since the CNT particles are intensively charged at negative ends through the charging device 150, they are vertically aligned with the fibers of the filter 170 charged with positive polarity, As shown in FIG.

Meanwhile, the injection nozzle 160 injects the CNT particles charged with a specific polarity (-) via the charging device 150 into a filter 170 in a state where an electric field is applied, in the form of a jet flow, The filter 170 is coated.

Specifically, the injection nozzle 160 includes a linear first flow path 161 through which charged CNT particles flow through the charging device 150, a first flow path 161 having a concentric axis with the first flow path 161, A second flow path 162 in which a part of the compressed air generated from the compressed air supply device 110 flows into the first flow path 161 and the second flow path 162, And a nozzle hole 163 through which the CNT particles having passed through the second flow path 162 are finally discharged.

At this time, the longitudinal shape of the second flow path 162 is formed such that the outer diameter gradually decreases toward the bottom. The second flow path 162 includes a sheath flow surrounding the flow of the CNT particles introduced through the first flow path 161 and a part of the compressed air generated from the compressed air supply device 110, .

Accordingly, the CNT particles injected through the first flow path 161 are combined with the sheath flow injected through the second flow path 162, and then injected into the filter 170 through the nozzle hole 163 at the lower end.

The sheath flow regulates the patterning area of the CNT particles coated on the filter 170. The sheath flows the inflow of compressed air into the second flow path 162 of the injection nozzle 160, Is generated, and is not generated unless the inflow of compressed air is performed.

For example, when there is no inflow of compressed air into the second flow path 162 of the injection nozzle 160, that is, when no sheath flow occurs, only the CNT particles passing through the first flow path 161 And is discharged to the filter 170 through the nozzle hole 163, so that the CNT particles can be patterned with a wider area.

On the contrary, when compressed air is introduced into the second flow path 162 and a sheath flow is generated, the CNT particles passing through the first flow path 161 are surrounded by the sheath flow from the second flow path 162 The CNT particles are surrounded by the sheath flow to reduce the width of the flow cross section of the CNT particles, so that the CNT particles can be intensively patterned on the filter 170 with a smaller area.

If the sheath flow is increased by increasing the flow rate and velocity of the compressed air flowing into the second flow path 162, the flow cross-sectional width of the CNT particles injected through the nozzle hole 163 is further reduced, The patterning area can be further narrowed and patterned intensively in a narrow manner.

As described above, by selectively opening and closing the flow of the compressed air supplied from the compressed air supply device 110 to the second flow path 162 of the injection nozzle 160, a sheath flow is generated or generated in the second flow path 162 And the patterning area of the CNT particles to be patterned on the filter 170 can be controlled. In addition, it is also possible to freely adjust the patterning area of the CNT particles patterned on the filter 170 by adjusting the flow rate and speed of the sheath flow by controlling the flow rate and speed of the compressed air flowing into the second flow path 162.

A flow meter 118 may be further provided between the compressed air supply device 110 and the spray nozzle 160 to measure the flow rate of the compressed air supplied to the spray nozzle 160.

The CNT filter manufacturing process using the electro-aerodynamic jet printing method of the present invention having the above-described configuration will be described with reference to the process chart of FIG.

First, the compressed air supply device 110 is driven to generate compressed air for transporting CNT particles, and the CNT solution in which the CNT particles are dispersed is sprayed through the vaporizer 120 to vaporize it into a droplet state. S210)

Then, the CNT gas vaporized in the droplet state is introduced into the drying apparatus 130 together with the compressed air as a carrier gas to remove moisture (moisture) contained in the CNT gas to dry it (S220)

Next, the CNT particles in a state in which water is removed through the drying device 130 are charged into the soft X-ray generator 140 to be in a charge neutral state (S230)

Then, the CNT particles, which have been charged to a neutral state via the X-ray generator 140, are charged to the negative (-) pole through the charging device 150 to make the CNT particles charge (S240)

At this time, both ends of the CNT particles charged through the charging device 150 are intensively charged to the negative (-) pole.

Then, when the CNT particles in the charged state are injected onto the charged filter 170 with the polarity (+) opposite to the polarity of the charged CNT particles through the injection nozzle 160, the charged CNT particles The CNT filter 170 is finally aligned on the fiber substrate of the filter 170 along the electric field formed around the filter 170 to finally complete the CNT filter 170. [

FIG. 3 is a scanning electron microscope (SEM) image of a CNT filter fabricated by the CNT filter manufacturing method of the present invention. FIG. 3 is a photograph of a filter substrate made of glass fiber.

Here, (b) on the right side of the SEM image of FIG. 3 is an enlarged view of a part of the left side (a).

As shown in the SEM image of FIG. 3, CNT particles are vertically aligned with each other on the glass fiber strands of the CNT filter manufactured by the electro-aerosol jet printing method of the present invention, .

4 is a graph showing the coating efficiency of the CNT filter fabricated using the CNT filter manufacturing system of the present invention.

Here, the coating efficiency of the CNT filter was measured by using a scanning mobility particle sizer (SMPS), which measures the ratio of the number of CNTs discharged from the filter to the number of CNTs injected into the filter. Here, the abscissa of the graph represents the diameter (nm) of CNT particles and the ordinate represents the number of CNT particles per unit volume (N / cm 3).

As can be seen from the graph of FIG. 4, when the number of the CNT particles injected into the filter is assumed to be 100, the number of the CNT particles that are not attached to the filter is less than 10 and the CNT coating efficiency of about 90% have.

5 is a graph showing the CNT particle desorption evaluation results of the CNT filter manufactured through the present invention.

This experiment is a measurement of the number of CNT particles desorbed from the filter 170 with passage of time (sec) when air is passed through the filter 170 at a constant pressure. At this time, the surface velocity of the air passing through the filter 170 was fixed at 0.2 m / s.

As can be seen from the experimental results of FIG. 5, it is confirmed that the number of CNT particles to be removed from the filter 170 is almost unchanged even if air is passed through the filter 170 for a predetermined time, . As described above, it can be confirmed that the CNT filter fabricated by using the CNT filter manufacturing system of the present invention is firmly attached to the fiber substrate of the filter 170 and coated thereon.

6 is a graph showing pressure drop measurement results of the CNT filter manufactured according to the present invention.

Here, the differential pressure measurement test of the filter 170 was performed based on the coating of CNT for 10 minutes, and the CNT filter was coated with a surface density of 3.7 ㅧ 10 ⁷ N / cm 3.

The abscissa of the graph represents the surface velocity (m / s) at which the air passes, and the ordinate represents the differential pressure Pa between the inlet and outlet of the filter 170.

As can be seen from the differential pressure measurement result of FIG. 6, the differential pressure between the both ends of the filter 170 is slightly increased in the case of the CNT coated filter. However, when the surface velocity of the air passing through the filter 170 is increased, As shown in Fig. Therefore, it can be seen that the effect of the CNT coating according to the present invention on the filter differential pressure change is negligible.

7 shows the particle distribution profile of the viral particles used for the measurement of the filter efficiency of the CNT filter fabricated by the present invention, and Fig. 8 shows the distribution profile of viral particles using the viral particles having the particle distribution profile shown in Fig. 7 This is a graph showing the results of confirming and predicting the virus collection efficiency according to the coating time through the virus collection experiment and theoretical calculation.

Bacteriophage MS2 virus was used in the filtration efficiency measurement experiment. At this time, the mode diameter of the virus particles collected through the filter was 37.2 nm and the total number concentration of virus particles was 8.64 ⁶ N / cc.

Generally, filters filter particles by three principles (Interception, Impaction, Diffusion)

At this time, the collection efficiency of the virus particles is calculated by using the following equation (1).

---(1)

---(One)

Here, Interception (E _R )

이며,

Lt;

이고,

이다.
At this time

ego,

to be.

And Impaction (E _I )

이며,

Lt;

이다.
At this time

to be.

Diffusion (E _D )

이며,

Lt;

이다.At this time

to be.

에서

이며,

in

Lt;

를 통해 구해질 수 있다.

. ≪ / RTI >

The parameters used in the above equation are as follows.

Since the calculation formula of the particle trapping efficiency of the above filter is a well-known calculation formula in the field of filter manufacturing, detailed description of each factor constituting the above formula will be omitted.

 The collection efficiency of the theoretically calculated filter and the collection efficiency of the filter measured through the experiment can be confirmed by the graphical result of FIG. 8 through the above calculation formula. That is, as shown in the graph of FIG. 8, it can be seen that the CNT filter fabricated by the present invention exhibits higher virus particle collection efficiency than the CNT-uncoated filter. (Maximum lift efficiency: 50% at 50 nm)

As described above, in manufacturing the CNT filter of the present invention, the CNT solution in which the CNT particles are dispersed is vaporized to remove moisture, and then charges are charged through the charging device 150. Then, the filter 170 is lifted up By applying a voltage having a polarity opposite to that of the charged electric charge to the donor electrode substrate 180, the CNT particles are vertically aligned on the fiber substrate of the filter 170 by applying an electric field, It is possible to rapidly produce the filter through a simple process, and the production time can be shortened to improve productivity. In addition, CNT particles can be coated directly on the filter without the necessity of a separate high-temperature heat treatment process unlike the conventional CVD process. Since all processes are performed under normal temperature and pressure conditions, a high temperature heat treatment process is required There is an advantage that the durability of the filter can be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein. Will be possible.

110: Compressed air supply device 112: Hepa filter
114: regulator 116,118: flow meter
120: vaporizer 130: drying device
140: Soft X-ray generator 150: Charging device
152, 182: voltage applying device 160: injection nozzle
161: first flow path 162: second flow path
163: nozzle hole 170: filter
180: electrode substrate

Claims (8)

A compressed air supply device for supplying compressed air for conveying the CNT particles;
A vaporizer for introducing compressed air supplied from the compressed air supply device and spraying a CNT solution containing CNT particles into a CNT gas;
A drying device for removing water contained in the vaporized CNT gas via the vaporizer;
A charging device for charging the CNT particles having moisture removed through the drying device to a specific polarity;
The charged CNT particles are injected in a jet flow form by a filter placed on an electrode substrate to which a voltage of a polarity opposite to the polarity of the charged CNT particles is applied, A spray nozzle for vertically aligning the nozzles;
A CNT filter manufacturing system using an electro-aerodynamic jet printing technique
The ink jet recording head according to claim 1,
A first flow path having a linear shape into which the charged CNT particles flow;
A second flow path formed concentrically with the first flow path and surrounding the first flow path, the second flow path forming part of the compressed air generated by the compressed air supply device to generate a sheath flow;
A nozzle hole in which the CNT particles injected through the first flow path are injected into the filter together with a sheath flow injected through the second flow path;
A CNT filter manufacturing system using an electro-aerodynamic jet printing technique
The CNT filter manufacturing system according to claim 1, wherein a flow meter is installed between the compressed air supply device and the vaporizer, and between the compressed air supply device and the spray nozzle.
The apparatus of claim 1, further comprising a soft X-ray generator between the drying device and the charging device to maintain the CNT particles in a charge neutral state. CNT filter manufacturing system using jet printing technique
(a) spraying a CNT solution containing CNT particles through a vaporizer to vaporize it in a CNT gas form;
(b) removing moisture contained in the vaporized CNT gas by using a drying device;
(c) charging the water-removed CNT particles to have a specific polarity using a charging device;
(d) injecting the charged CNT particles in a jet flow form through a filter on an electrode substrate to which a voltage of a polarity opposite to the polarity of the charged CNT particles is applied, Printing the particles in a vertical alignment on the fiber substrate of the filter;
A method for fabricating a CNT filter using an electro-aerodynamic jet printing technique.
6. The CNT filter manufacturing method according to claim 5, wherein part of the compressed air provided for transporting the CNT particles flows into the injection nozzle to provide a sheath flow. .
[7] The method of claim 5, wherein between step (b) and step (c), CNT particles charged with CNTs having moisture removed therefrom are maintained in a charge neutral state, The method of claim 1, wherein the CNT filter is fabricated using an electro-aerosol jet printing technique.
A CNT filter manufactured by the CNT filter manufacturing method according to any one of claims 5 to 7,

Images