KR101118080B1 - Method of manufacturing nanofiber web - Google Patents

Abstract

The present invention relates to a method for manufacturing a nanofiber web using an electrospinning method, wherein a polymer solution is supplied to a nozzle 30 subjected to a high voltage, and then a polymer solution supplied to the nozzle 3 is opposite to the nozzle 3. When producing a nanofiber web by electrospinning toward the collector (4) is a high voltage is applied to the air injection device (7) installed on both sides of the nozzle block in which the nozzles are arranged to inject air in the electrospinning direction of the polymer solution It is characterized by.

The present invention has the advantage of effectively preventing the electrospun nanofibers from being volatilized out of the collector surface to improve the integration and productivity of the nanofiber web.

Electrospinning, Air Spray, Nozzle, Integration, Web, Nanofiber, Collector

Description

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

The present invention relates to a method for manufacturing a nanofiber web using an electrospinning method, and more particularly, to a method for manufacturing a nanofiber web that can effectively prevent the electrospun nanofibers from being volatilized out of the collector surface. will be.

Electrospinning was first introduced in Germany in the 1930s in 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 5 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.

5 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. 4, the polymer solution is supplied to the plurality of nozzles 3 subjected to the high voltage through the metering pump 2, and then the high voltage having the opposite charge to the nozzle is supplied. Nanofiber web was prepared by electrospinning on a fiber substrate placed on the hanging collector (4).

4 is a schematic diagram of a conventional electrospinning process.

According to the conventional method, the nanofibers electrospun from the nozzle 3 are volatilized to a place other than the surface of the collector 4, thereby lowering the productivity or decreasing the uniformity of the manufactured nanofiber web. .

An object of the present invention is to effectively prevent the electrospun nanofibers from being volatilized out of the collector surface to improve productivity and the integration of nanofibers, and to improve the uniformity of the nanofiber webs.

According to the method of manufacturing a nanofiber web according to the present invention for achieving the above object, the polymer solution supplied to the nozzle (3) after supplying the polymer solution to the high voltage is applied to the nozzle (3) as opposed to the nozzle (3) When the nanofiber web is manufactured by electrospinning toward the collector 4, which is charged with a high voltage, the air is sprayed to the electrospinning direction of the polymer solution by an air spraying device 7 installed on both sides of the nozzle block. It is characterized by spraying.

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

First, the present invention supplies the polymer solution stored in the polymer solution main tank 1 to the nozzle 3 under high voltage through the polymer solution supply pump 2 as shown in FIGS.

The nozzles 3 are arranged side by side on the nozzle block.

Next, the polymer solution supplied to the nozzle 3 is electrospun toward the collector 4 subjected to the high voltage to volatilize the nanofibers, and the volatilized nanofibers are laminated on the collector 4 to form nano Prepare a fibrous web.

The present invention is characterized in that the nozzle 3 is electrospun to the polymer solution and at the same time the air is sprayed to the electrospinning direction of the polymer solution to the air spraying device 7 provided on both sides of the nozzle block in which the nozzles are arranged .

1 to 2 are process schematics of the present invention.

Each of the nozzle 3 and the collector 4 is subjected to a high voltage with a different charge for electrospinning.

As shown in FIG. 3, the air spraying device is a pipe having a hollow inside and having holes 7a formed in the surface of the air spraying device.

3 is a perspective schematic view of the air injector 7 used in the present invention.

The polymer solution supplied to the nozzle 3 has a higher stress in the normal vector direction than the surface tension of the polymer solution due to the high voltage applied to the nozzle 3 and the collector 4 to form a polymer jet.

The polymer jet is directed toward the collector 4 having the opposite charge, and maintains a jet state from the nozzle 3 to a predetermined period, and then volatilizes to change into the nanofibers 70 and onto the collector 4. Is integrated in.

At this time, the flow of air injected from the air injector 7 effectively prevents the electrospun nanofibers from being volatilized out of the surface of the collector 4.

The polymer solution is polyamide resin, polyurethane resin, polyester resin, polystyrene resin, cellulose resin, polyvinylacetate resin, polyvinyl chloride resin, polyvinyl alcohol resin, polysulfone resin, polyacrylonitrile resin, polymethylmetha Any soluble fiber-forming polymer such as acrylate resin, 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.

On the collector 4, a fibrous base or film may be located.

The collector 4 is located on the horizontal, lower, upper surface, etc. of the nozzle 3, and moves at a constant linear velocity.

The surfaces of the nozzle 3 and the collector 4 are gold, silver, tungsten, copper, stainless steel, alloys thereof, and the like, and more preferably, platinum is coated on stainless steel.

The present invention has the advantage of effectively preventing the electrospun nanofibers from being volatilized out of the collector surface to improve the integration and productivity of the nanofiber web.

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 1 is supplied to the nozzles 3 arranged on the nozzle block with the high voltage of the cathode applied through the polymer solution supply pump 2. Then, the polymer solution supplied to the nozzle 3 through the nozzle 3 is sprayed toward the collector 4 subjected to the high voltage of the anode, and then the volatilized nanofibers are laminated on the collector 4 to form a nanofiber web. To prepare.

At this time, 0.5 kg / cm 2 air was sprayed in the same direction as the injection direction of the polymer solution with the injection of the polymer solution through the nozzle 3 and the air injection device 7 provided on both sides of the nozzle block.

At this time, a voltage of 55,000 volts was applied to the nozzle 3 and the collector 4 by using a voltage generator 60 connected to an AC power source of 220 volts and 60 Hz.

The surfaces of the nozzle 3 and the collector 4 are made of a material coated with platinum on stainless steel, and the distance between the nozzle 3 and the collector 4 is 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 nanofiber web was manufactured under the same conditions as in Example 1 except that the position of the collector, the polymer and solvent constituting the polymer solution, the voltage applied to the collector and the nozzle, and the distance between the nozzle and the collector were changed as shown in Table 1. It was.

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 Position of collector (4) Polymer
Kinds menstruum Voltage
(volt) Nozzle-collector spacing (cm) Example 1 Above the lower part of the nozzle (3)
Chi Polyamide Formic acid 55,000 30 Example 2 Lower position of the nozzle (3) Polyurethane Dimethylformamide 35,000 30 Example 3 Lower position of the nozzle (3) Polyamide Formic acid 70,000 45 Example 4 Nozzle (3) and horizontal position Polyurethane Dimethylformamide 50,000 45 Example 5 Nozzle (3) and horizontal position Polypropylene toluene 40,000 30 Example 6 Nozzle (3) and horizontal position Polypropylene toluene 60,000 45

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. 4, 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 anode is applied through the polymer solution supply pump 2, and then, The nanofibers were volatilized by spraying toward the collector 4 of the metal plate under high voltage, and then the volatilized nanofibers were laminated on the collector to prepare a nanofiber web.

At this time, it is omitted to inject the air in the injection direction of the polymer solution using the air injection device (7), a plurality of nozzles (3) and the collector (4) is a voltage generator (220 volts, 60Hz AC power is connected) ), A voltage of 55,000 volts was applied, 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.

Comparative Example 1 to Preparation Conditions of Comparative Example 6 division Air spray
Whether Polymer Type menstruum Voltage
(volt) Nozzle
Discharge
(ml / min) Nozzle-Collector Spacing
(Cm) Comparative Example 1 No spray Polyamide Formic acid 55,000 0.5 30 Comparative Example 2 No spray Polyurethane Dimethylformamide 35,000 0.6 30 Comparative Example 3 No spray Polyamide Formic acid 70,000 0.7 45 Comparative Example 4 No spray Polyurethane Dimethylformamide 50,000 0.8 45 Comparative Example 5 No spray Polypropylene toluene 40,000 0.5 30 Comparative Example 6 No spray Polypropylene toluene 60,000 0.8 45

Property evaluation result division Breathable average
(g / ㎡ / day) Permeability Standard Deviation
(g / ㎡ / day) fault
(dog) Example 1 14,000 280 0 Example 2 15,000 300 0 Example 3 17,000 290 0 Example 4 16,000 310 0 Example 5 14,000 290 0 Example 6 17,000 270 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 substantially 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 Moisture permeability

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 to 2 are process schematic diagrams of the present invention.

3 is a perspective schematic view of the air injector 7 used in the present invention.

4 is a schematic diagram of a conventional electrospinning process.

5 is an electron micrograph of the nanofiber web.

* Description of the main parts of the drawings

1: Polymer solution main tank 2: Polymer solution supply pump

3: nozzle 4: collector

5: voltage transfer rod 6: voltage generator

7: Air injection device 8: Air supply device

7a: Hole punched in the air sprayer

Claims (6)

After supplying the polymer solution to the nozzle 30 under high voltage, the polymer solution supplied to the nozzle 3 is electrospun toward the collector 4 under high voltage having a charge opposite to that of the nozzle 3. In manufacturing the air spraying device 7 which is installed on both sides of the nozzle block in which the nozzles are arranged, the inside is hollow and a pipe formed with holes 7a bored in the air spraying device on the surface thereof. Method of producing a nanofiber web, characterized in that for spraying air in the direction of electrospinning of the polymer solution. delete The method of claim 1, wherein the polymer solution is a polyamide resin, polyurethane resin, polyester resin, polystyrene resin, cellulose resin, polyvinylacetate resin, polyvinyl chloride resin, polyvinyl alcohol resin, polysulfone resin, polyacrylonitrile A method for producing a nanofiber web, characterized in that one selected from the group consisting of resins, polymethylmethacrylate resins, polystyrene resins, polyacrylic acid resins, polyolefin resins, wholly aromatic polyamide resins, and polyvinylidene fluoride resins. A method according to claim 1, characterized in that the collector (4) moves at a constant linear velocity. The method of claim 1, wherein the surface of the nozzle (3) and the collector (4) is made of a nanofiber web, characterized in that made of one material selected from gold, tungsten, silver, copper, stainless steel and alloys thereof. Way. The method of manufacturing a nanofiber web according to claim 1, characterized in that a fibrous base or film is placed on the collector (4).

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