KR20100019169A - Method of manufacturing nanofiber web - Google Patents

Abstract

PURPOSE: A manufacturing method of nanofiber web is provided to reduce manufacturing costs while easily managing manufacturing processes, and to conveniently and easily repair and manage a facility of the nanofiber web. CONSTITUTION: A manufacturing method of nanofiber web includes a step for volatilizing nanofiber(70) by electropinning a polymer solution storing in a polymer solution tank through a minute hole(41) perforated on a perforated board(40) and a step for laminating the volatilized nanofiber on a collector. A perforated board is contacted with the polymer spinning liquid, and is installed on a polymer liquid bath. The collector is located on the top of the perforated board. The diameter of the perforated minute holes is 0.2~1.0 mm.

Description

Method of manufacturing nanofiber web {Method of manufacturing nanofiber web}

The present invention relates to a method of manufacturing a nanofiber web using an electrospinning method, and more specifically, manufacturing cost is reduced by electrospinning a polymer solution through micropores perforated in a porous plate instead of a conventional nozzle, and a manufacturing process The present invention relates to a method for producing a nanofiber web, which can be easily managed and maintenance of a facility is also simple.

Electrospinning was first introduced in Germany in the 1930s as a relatively simple way to produce ultrafine fibers (hereinafter referred to as "nano fibers") with diameters of tens to hundreds of nm. However, the technology of the time was limited to commercialization of this technology, so it was not received attention, and research began again until the 1970s, and full-scale research began only after the 2000s.

Electrospinning applied a high voltage of several thousand to tens of thousands of volts to the polymer solution, and the force of the tangential vector exceeding the surface tension of the solvent was applied from the polymer solution to form a fine polymer jet from the polymer solution. The band advances rapidly toward the object. The jets of polymer jets are then dispersed and scattered back into a number of fine fibers, which have a diameter of tens to hundreds of nanometers.

Electrospinning can be used to produce nanofiber webs as shown in Figure 3 consisting of nanofibers having a thickness of several tens to hundreds of nanometers from a polymer solution, using them for high functional clothing, ultra-precision filters, cell culture materials (scaffold). High performance products, such as) can be obtained.

3 is an electron micrograph of a nanofiber web.

In order to commercially manufacture a nanofiber web, Korean Patent No. 0412241, Korean Patent No. 0422459 and Korean Patent Application No. 2005-15610 propose a method of electrospinning a plurality of nozzles through a plurality of nozzles.

Specifically, according to the conventional method, as shown in FIG. 2, the polymer solution is supplied to the plurality of nozzles 3 under high voltage through the metering pump 2, and then a high voltage having opposite charge to the nozzle is applied. Nanofiber web was prepared by electrospinning on a fiber substrate placed on the hanging collector (4).

2 is a schematic diagram of a conventional electrospinning process.

The conventional method described above has excellent productivity and excellent uniformity compared to using one nozzle. However, the prior art has a very high possibility of defects due to clogging in the nozzle, and the need for removing the nozzles from time to time causes a hassle. In addition, since a high voltage of thousands to tens of thousands of volts is applied to each nozzle, it is difficult to obtain a uniform nanofiber web because the electric field in each nozzle affects the direction of the polymer jet generated in the nozzle.

In addition, the formation of polymer solution droplets at the nozzle tip is different depending on the type of polymer, molecular weight of polymer, viscosity of solvent, temperature, etc. This is a hassle to change the specification to conform. In order to optimize the size of the nozzle, it is necessary to investigate the inner diameter and length of a suitable nozzle through separate tests, and to prepare and install a nozzle suitable for the nozzle. Therefore, the preparation period for producing various kinds of nanofiber webs becomes very long. .

In order to solve this problem, in actual commercial-type electrospinning equipment, a technique of arranging nozzles in a diagonal direction of the substrate or dividing into several layers and arranging them alternately with each other has been applied. It must be cleaned and it is difficult to fundamentally solve the problem of the mutual influence of the polymer jets by the electric field in the nozzle.

In addition, the conventional method has a problem that the manufacturing cost is increased and the equipment is complicated.

An object of the present invention is to significantly improve the uniformity of the nanofiber web by solving such a conventional problem.

Another object of the present invention is to reduce the manufacturing cost, easy process management and easy maintenance and maintenance of the manufacturing process of the nanofiber web.

The method of manufacturing a nanofiber web according to the present invention for achieving the above object, the polymer solution contained in the polymer solution bath 30 is installed on the polymer solution bath 30 in a state where the high voltage is applied to the lower portion The collector 50 located above the porous plate 40 in a state where a high voltage is applied through the micropores 41 drilled in the porous plate 40 in contact with the polymer spinning solution in the polymer solution bath 30. After electrospinning toward) to volatilize the nanofibers 70, the volatilized nanofibers 70 are laminated on the collector 50.

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

First, the present invention stores and stores the polymer solution stored in the polymer solution main tank 10 as shown in FIG. 1 through the polymer solution supply pump 20 to the polymer solution bath 30.

Next, a collector located in the upper portion of the porous plate 40 through the micropores 41 of the porous plate 40 installed on the polymer solution bath 30 to the polymer spinning solution stored in the polymer solution bath 30 Electrospun toward 50 to volatilize the nanofibers 70, and then the volatilized nanofibers 70 are laminated on the collector 50 to produce a nanofiber web.

1 is a process schematic diagram of the present invention.

Each of the porous plate 40 and the collector 50 is subjected to a high voltage with a different charge for electrospinning.

The lower portion of the porous plate 40 is in contact with the polymer solution stored in the polymer solution bath 30, and has a structure in which the micro holes 41 are uniformly perforated.

It is preferable that the diameter of the microhole 41 perforated in the porous plate 40 is 0.2-1.0 mm.

If the diameter of the micropore 41 is smaller than 0.2mm, the phenomenon that the micropore 41 is easily clogged due to the polymer solution may occur frequently. If the diameter of the micropore 41 is larger than 10mm, the electrospunness is inferior and the diameter of the nanofibers manufactured is desired. Thicker problems may occur.

The polymer solution stored in the polymer solution bath 30 is raised above the microholes 41 drilled in the porous plate 40 by an electric force or capillary phenomenon generated by the high voltage applied to the porous plate 40. The polymer solution raised above the microholes 41 perforated in the porous plate 40 has a greater stress in the direction of the normal vector than the surface tension of the polymer solution due to the high voltage applied to the porous plate 40 and the collector 50. (Jet) is formed.

The polymer jet is directed toward the collector 50 having the opposite charge, and maintains a jet state from the porous plate 40 to a predetermined period, and then volatilizes to change to the nanofiber 70 to collect the collector 50. Is integrated into the phase.

The polymer solution may be polyamide resin, polyurethane resin, polyester resin, polystyrene resin, cellulose, polyvinylacetate, polyvinylchloride, polyvinyl alcohol resin, polysulfone resin, polyacrylonitrile resin, polymethylmethacrylate resin All soluble fiber-forming polymers such as polystyrene resin, polyacrylic acid resin, polyolefin resin, wholly aromatic polyamide resin or polyvinylidene fluoride resin can be used.

Moreover, there is no restriction | limiting also in the kind of solvent for melt | dissolving a high molecular substance. The solvent is limited depending on the polymer, and the solvent can be freely determined depending on the polymer used to prepare the nanofiber web. Moreover, there is no restriction also about the manufacturing method of a polymer solution.

The concentration of the polymer solution can range from as low as 1% or less to as high as 50% or less.

In addition, two or more kinds of polymers may be used simultaneously. It is also possible to dissolve two or more kinds of different polymers in a solvent, or to dissolve and use polymers having different properties such as molecular weight in solvents.

The fibrous substrate or film may be positioned on the collector 50.

The collector 50 is positioned above the porous plate 40 and moves at a constant linear velocity.

The surface of each of the porous plate 40 and the collector 50 is gold, silver, tungsten, copper, stainless steel or alloys thereof, and more preferably, platinum is coated on stainless steel.

Thus, in the present invention, by using the porous plate 40 instead of using a plurality of nozzles, there is no hassle to clean and manage a plurality of nozzles one by one, and uniformity of the nanofiber web according to the arrangement of the plurality of nozzles. There is no disadvantage that depends. In addition, there is no hassle to change the inner diameter and length of the nozzle according to the type and viscosity of the polymer, so it is very easy to change the varieties. There is no advantage to this. In addition, compared with the conventional electrospinning apparatus using a top-down nozzle, defects such as undissolved polymers and the like are not dispersed on the substrate, so that a nanofiber web with few defects can be obtained.

The present invention is low in manufacturing cost, greatly improves the uniformity of the nanofiber web, easy to change the variety and process management

In addition, the present invention is easy to repair and maintain the equipment and can simplify the equipment.

As a result, the nanofiber web produced by the present invention is useful as a high performance filter, optical material and the like.

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

Example  One

Polyamide was dissolved in formic acid at a concentration of 8% to prepare a polyamide solution at 25 ° C. and used as a polymer solution.

According to the process shown in FIG. 1, the polyamide solution stored in the polymer solution main tank 10 is supplied to and stored in the polymer solution bath 30 through the pump 20, and then the negative electrode is placed on the polymer solution bath 30. The high voltage of the positive electrode through the fine holes 41 perforated in the porous plate 40 is installed in the bottom portion is in contact with the polyamide solution stored in the polymer solution bath 30 while the high voltage of The nanofibers are volatilized by spraying toward the collector 50 located in the upper portion of the porous plate 40 in the suspended state, and the volatilized nanofibers 70 are laminated on the collector 50 to form a polyamide nanofiber web. Was prepared.

At this time, a voltage of 55,000 volts was applied to the porous plate 40 and the collector 50 by using the voltage generator 60 connected to an AC power source of 220 volts and 60 Hz.

The surface of each of the porous plate 40 and the collector 50 is made of a material coated with stainless platinum, the diameter of the fine hole 41 perforated in the porous plate 40 was 0.5mm.

In addition, the space | interval of the porous board 40 and the collector 50 was set to 30 cm.

The results of evaluating various physical properties of the prepared nanofiber webs are shown in Table 3.

Example  2- Example  6

The same conditions as in Example 1 except for changing the type of polymer and solvent constituting the polymer solution, the diameter of the micropores in the porous plate, the voltage applied to the collector and the porous plate and the distance between the porous plate and the collector as shown in Table 1 A nanofiber web was prepared.

The results of evaluating various physical properties of the prepared nanofiber webs are shown in Table 3.

Manufacturing conditions of Example 1 to Example 6 division Electrospinning device Polymer type menstruum Voltage (volts) Perforated plate-collector spacing (cm) Perforated Plate Micropore Diameter (mm) Example 1 Perforated Plate Polyamide Formic acid 55,000 30 0.5 Example 2 Perforated Plate Polyurethane Dimethylformamide 35,000 30 0.7 Example 3 Perforated Plate Polyamide Formic acid 70,000 45 0.9 Example 4 Perforated Plate Polyurethane Dimethylformamide 50,000 45 0.3 Example 5 Perforated Plate Polypropylene toluene 40,000 30 0.2 Example 6 Perforated Plate Polypropylene toluene 60,000 45 1.0

Comparative Example  One

Polyamide was dissolved in formic acid at a concentration of 8% to prepare a polyamide solution at 25 ° C. and used as a polymer solution.

According to the process shown in FIG. 2, the polyamide solution stored in the polymer solution main tank 1 is supplied to the plurality of nozzles 3 in which the high voltage of the positive electrode is applied through the metering pump 2, and then the high voltage of the negative electrode is reduced. The nanofibers were volatilized by spraying toward the collector 4 of the hanging metal plate, and then the volatilized nanofibers were laminated on the collector to prepare a nanofiber web.

At this time, a voltage of 55,000 volts was applied to the plurality of nozzles 3 and the collector 4 by using a voltage generator 6 connected to an AC power source of 220 volts and 60 Hz, and the nozzle discharge amount was 0.5 ml / min.

In addition, the space | interval of the nozzle 3 and the collector 4 was set to 30 cm.

The results of evaluating various physical properties of the prepared nanofiber webs are shown in Table 3.

Comparative Example  2- Comparative Example  6

Nanofiber web under the same conditions as in Comparative Example 1 except for changing the polymer and solvent constituting the polymer solution, the voltage applied to the collector and the nozzles, the discharge amount of the nozzle and the interval between the nozzle and the collector as shown in Table 2 Was prepared.

The results of evaluating various physical properties of the prepared nanofiber webs are shown in Table 3.

Preparation conditions of Comparative Example 1 to Comparative Example 6 division Electrospinning device Polymer Type menstruum Voltage (volts) Nozzle Discharge Rate (ml / min) Nozzle-collector spacing (cm) Comparative Example 1 Nozzle Polyamide Formic acid 55,000 0.5 30 Comparative Example 2 Nozzle Polyurethane Dimethylformamide 35,000 0.6 30 Comparative Example 3 Nozzle Polyamide Formic acid 70,000 0.7 45 Comparative Example 4 Nozzle Polyurethane Dimethylformamide 50,000 0.8 45 Comparative Example 5 Nozzle Polypropylene toluene 40,000 0.5 30 Comparative Example 6 Nozzle Polypropylene toluene 60,000 0.8 45

Property evaluation result division Moisture permeability average (g / ㎡ / day) Water vapor permeability standard deviation (g / ㎡ / day) Defects (dog) Example 1 14,000 250 0 Example 2 15,000 300 0 Example 3 17,000 320 0 Example 4 16,000 300 0 Example 5 14,000 260 0 Example 6 17,000 280 0 Comparative Example 1 18,000 2,500 11 Comparative Example 2 18,000 1,800 12 Comparative Example 3 15,000 1,900 6 Comparative Example 4 18,000 1,500 10 Comparative Example 5 19,000 2,200 12 Comparative Example 6 20,000 2,000 9

As can be seen from the above evaluation results, the standard deviation of the water vapor transmission rate of the nanofiber webs prepared in Examples 1 to 6 is very uniform, not more than 500 g / m 2 / day. In addition, a very good quality nanofiber web without defects on the nanofiber web was obtained.

However, the nanofiber webs prepared in Comparative Examples 1 to 6 exhibited almost the same moisture permeability as Examples 1 to 6, but showed a very high standard deviation of 2,000 g / m 2 / day or more. In addition, there are also many defects compared to the nanofiber web prepared in Examples 1 to 6 at the level of 6 to 12. The defects are mostly polymer solutions away from the nozzles, and the clogging of nozzles has also been affected by varieties.

Properties of Table 3 were evaluated by the following method.

Of nanofiber web Breathable

The water vapor permeability of the nanofiber web was evaluated 10 times with different measurement sites, and the average value and standard deviation were calculated. The method of evaluating moisture permeability is to evaluate the number of grams of moisture passed after 24 hours of application of moisture to a fabric under a certain pressure, according to Korean Industrial Standard KS K 0594.

Drawbacks of Nanofiber Web

The number of defects within 45 cm wide and 5 m long for the nanofiber web is visually determined. The defects were evaluated by the number of points where the polymer solution fell and the number of points where no nanofibers were applied.

1 is a process schematic diagram of the present invention.

Figure 2 is a schematic diagram of a conventional electrospinning process.

3 is an electron micrograph of the nanofiber web.

* Description of the main parts of the drawings

1, 10: polymer solution main tank 2, 20: polymer solution supply pump

30: polymer solution bath 40: porous plate

41: micropores perforated in the perforated plate 4, 50: collector

6, 60: voltage generator 70: nanofibers

3: nozzle block 5: voltage transfer rod.

Claims (6)

The porous plate 40 is installed on the polymer solution bath 30 in a state where a high voltage is applied to the polymer solution contained in the polymer solution bath 30 so that a lower portion thereof contacts the polymer spinning solution in the polymer solution bath 30. In the state in which a high voltage is applied through the micro holes 41 perforated) to electrospin toward the collector 50 located on the upper portion of the porous plate 40 to volatilize the nanofibers 70, and then volatilized nano Method for producing a nanofiber web, characterized in that the fiber (70) is laminated on the collector (50). The method of manufacturing a nanofiber web according to claim 1, wherein the diameter of the micropores (41) perforated in the porous plate is 0.2 to 1.0 mm. The method of claim 1, wherein the polymer solution is polyamide resin, polyurethane resin, polyester resin, polystyrene resin, cellulose, polyvinylacetate, polyvinyl chloride, polyvinyl alcohol resin, polysulfone resin, polyacrylonitrile resin, poly A method for producing a nanofiber web, characterized in that it is one selected from the group consisting of methyl methacrylate resin, polystyrene resin, polyacrylic acid resin, polyolefin resin, wholly aromatic polyamide resin, and polyvinylidene fluoride resin. The method of claim 1, wherein the collector (50) moves at a constant linear velocity. The nanofiber web according to claim 1, wherein the surface of each of the porous plate 40 and the collector 50 is made of one material selected from gold, silver, tungsten, copper, stainless steel and alloys thereof. Manufacturing method. The method of manufacturing a nanofiber web according to claim 1, wherein a fibrous base or a film is positioned on the collector (50).

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