KR20070097936A - Anti-bacterial nanofiber filter media and manufacturing method therof containing silver nano particles - Google Patents

Abstract

A nanofiber filter medium and a method for manufacturing the same are provided to prevent the separation of silver nanoparticles, by highly dispersing silver nanoparticles on a surface of a nanofiber layer through electro-spinning and electro-spraying. A nanofiber layer(80) is formed on a nonwoven fabric medium(10) for a filter by electro-spinning a nanofiber forming polymer solution. Silver nanoparticles are dispersed on a surface of the nanofiber layer by electro-spraying a silver nanoparticle containing solution. The forming of the nanofiber layer and the dispersing of the silver nanoparticles are continuously performed on a roll process. Another nonwoven fabric medium is additively attached to the surface of the nanofiber layer.

Description

Anti-bacterial Nanofiber Filter Media and Manufacturing Method Therof Containing Silver Nano Particles}

1 is a schematic view of the electrospinning and electrospray apparatus according to the present invention,

2 is a perspective view of a cross section of a filter medium made of a nonwoven filter medium for filters and electrospun silver nanoparticle-containing nanofibers according to the present invention;

Figure 3 is a (a) 5,000 times, (b) 10,000 times, (c) 30,000 times magnified electron micrograph of the PVA nanofibers according to the present invention,

4 is a transmission electron micrograph of a PAN nanofiber containing silver nanoparticles according to the present invention,

5 is an electron micrograph of (a) 500 times, (b) 18,000 times magnification of PBT nanofibers according to the present invention;

Figure 6 is a photograph showing the separation of the nanofibers spun on the (a) filter nonwoven media for filter, (b) the nonwoven media for filter according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: filter non-woven media 21: electrospinning nozzle

22: kitchen liquid tank 31: electrospray nozzle

32: silver nano solution tank 40: current collector

50: voltage generator 60: calendar

70: winder 80: nanofiber containing silver nanoparticles

The present invention provides a method for producing a nanofiber filter media to maximize the antibacterial and bactericidal power by highly dispersing silver nanoparticles by an electrospray method on the surface of the nanofiber layer formed on the substrate by an electrospinning method and It relates to a nanofiber filter media produced by.

In recent years, the use of materials that use antimicrobial and bactericidal power of silver nano is increasing in addition to well-being winds, air purifiers, air conditioner filters, automotive air filters, and filters for water purifiers. The most common method for producing silver nano-containing fibers for filter media is to produce antimicrobial fibers by coating silver nanoparticles on the fibers or adding silver nanoparticles inside the yarn. However, in the case of the coating method, there is a disadvantage in that the silver nanopowder is desorbed when used due to the weak bonding force between the silver nanopowder and the fiber. It is difficult to be dispersed. In addition, when contained in the yarn there is a disadvantage that can not fully utilize the excellent effect of the silver nano, in order to use as a filter medium, non-woven fabric manufacturing process needle punching, spun-lace, air (air) There are disadvantages in that process costs are increased because additional processes such as -laid and wet-laid processes, chemical and thermal methods are additionally required.

In general, the production of synthetic fibers is achieved by melting and solution spinning, melt-blown spinning, composite spinning, or by combining conventional spinning methods. There are various spinning methods such as polymer blend spinning, melt spray spinning, flash spinning, electrospinning, etc., but among them, the electrospinning method is known as the most effective means.

The method of preparing the antimicrobial fiber is a general method of manufacturing by mixing organic and inorganic antimicrobial agents to the fiber material, but in the case of organic antimicrobial agents, there is a problem that the antimicrobial power is not available due to the decomposition and dissolution of the organic antimicrobial agent during melting and solution spinning. In addition, the inorganic antimicrobial agent has been produced by attaching a silver compound to the porous ceramic powder, but the size of the silver compound is within several tens of μm has been known to have limitations in the fiber trimming and microfiber production. In order to solve this problem, there is an attempt to manufacture antimicrobial fibers by dispersing and mixing silver nanopowders in a spinning solution.

Republic of Korea Patent No. 10-0484473 is characterized in that to form a mixture by mixing and stirring 97 ~ 99.9% by weight of the synthetic resin and 0.1 to 3% by weight of the nano-silver, it is characterized by producing a fiber. However, the present invention has a disadvantage in that the silver nanoparticles penetrate into the fiber during spinning, thereby providing a cause of decrease in strength of the fiber and trimming during spinning. In addition, in order to enhance the antimicrobial and bactericidal power of silver nano, the silver nano should be exposed to the fiber surface to form an interface contacting with bacteria and contaminants, but it is manufactured in a form mixed with spinning solution. It is manufactured to have the disadvantage of minimizing sterilization and antibacterial activity.

In Korean Patent No. 10-0535916, silver precursor (silver nitrate) is dissolved into fine droplets, and then heat treated and cooled through a reactor to prepare silver nanoparticles, which are made into master batch chips, and then mixed with raw materials and master batch chips. To produce a fiber yarn. The present invention includes the steps of directly manufacturing the silver nanoparticles and spinning step, the overall process is complicated, there is a fear that the manufacturing cost increases, and the silver nanoparticles produced by the diameter of the manufactured fibers within several tens of micrometers It is included in the antimicrobial and bactericidal power is reduced, and may cause the trimming during the strength and spinning of the fiber.

In other words, in the case of the registered patents 10-0484473 and 10-0535916, when used as a filter medium for various purification and purification, additional processes such as weaving, weaving, and non-woven fabric production are required, and the diameter of the manufactured fiber is about several tens of micrometers. There is a problem to make the best use of antibacterial and antibacterial activity.

Accordingly, an object of the present invention is to provide a method for producing a nanofiber filter medium which can stably fix silver nanoparticles on the surface of a nanofiber layer and stably fix the silver nanoparticles, thereby preventing the nanoparticles from being easily detached. It is to provide a nanofiber filter media.

In order to achieve the above object, one embodiment of the present invention comprises the steps of: a) electrospinning the nanofiber forming polymer solution on the filter nonwoven media to form a nanofiber layer; b) a method of manufacturing silver nanoparticle-containing nanofiber filter media comprising electrospraying a silver nanoparticle-containing solution on the surface of the nanofiber layer to disperse the silver nanoparticles on the surface of the nanofiber layer. To provide.

In addition, another embodiment of the present invention provides a nanofiber filter medium produced by the above production method.

Hereinafter, as an embodiment of the present invention, a method for manufacturing the antimicrobial nanofiber filter media will be described in detail with reference to the accompanying drawings.

The fiber material used as the filter nonwoven fabric filter of the present invention is preferably polyester, polyvinyl, polyvinyl alcohol, polyacrylonitrile, polyolefin, polypropylene, carbon / active carbon fiber, etc. It can be used, the thickness of the filter medium nonwoven fabric can be from several tens of ㎛ to several mm, can be selected in consideration of the purpose and pressure loss of the final filter media.

 Here, nanofibers are prepared by electrospinning the polymer spinning solution on the filter nonwoven media 10 using the electrospinning nozzle 21 and the collector 40 under voltage.

The current collector serves to prevent the nanofibers or nanoparticles from being dispersed by using an air cushion to collect the nanofibers.

In the electrospinning process, the polymer solution in the kitchen solution tank 22 of FIG. 1 is continuously supplied into the electrospinning nozzle 21 subjected to high voltage through a metering pump, and the electrospinning is performed on the filter nonwoven media 10 for the filter. A nanofiber layer is formed on the nonwoven fabric filter 10. At this time, polyvinyl alcohol, polyacrylonitrile, polybutylene terephthalate are preferred as the polymer to be emitted, and the solvent is water, dimethylformamide (NMF), dimethylacetamide (DMAc), tetra Fluoroacetic acid (tetrafluoroacetic acid, TFA) and the like may be used alone or in combination, and a suitable solvent may be selected and used according to the polymer. The concentration of the spinning solution is about 10 to 50% by weight, and can be selected in consideration of the viscosity, surface tension, applied voltage, and the like of the spinning solution. At this time, the voltage used is applied by applying a voltage of 20kV ~ 100kV in the voltage generator 50, the distance between the spinneret and the current collector is carried out to be less than 10cm or less than 1m. At this time, the diameter of the fiber produced by electrospinning is preferably about 100 ~ 1000nm.

As a step of uniformly dispersing the silver nanoparticles on the prepared nanofiber layer, it is electrosprayed through an electrospray nozzle 31 in which a solution in which silver nanoparticles are dispersed on the prepared nanofiber layer. In this case, the silver nanoparticles are preferably contained in 0.005 to 10% by weight relative to the total weight of the nanofibers, but if the amount of silver nanoparticles contained is less than 0.005% by weight, the contact area between silver nanoparticles and bacteria is significantly reduced. The disadvantage is that the antimicrobial activity is lowered, and as the silver nano content increases, the contact area with the fungus increases relatively to maximize the antimicrobial activity, but when it exceeds 10% by weight, aggregation between silver nanoparticles occurs and the surface area is increased. There is a problem that this decreases, the manufacturing cost increases.

In the electrospray process, electrospray is performed while continuously supplying the solution of the silver nanosolution tank 32 in which silver nanoparticles are dispersed into the electrospray nozzle 31 under high voltage through a metering pump. The injection solution is prepared by dispersing the silver nanopowder in a single or mixed solvent selected from water, acetone, DMF, DMAc, TFA. In order to lower the surface tension of the solvent and induce volatility, it is preferable to add 10 to 80% by weight of acetone in the solvent, and the concentration of the silver nanoparticle-containing solution prepared by dispersing silver nanoparticles in the solvent is 0.001 to 10% by weight. % Is preferred, taking into account the viscosity of the spinning solution, the surface tension, applied voltage, etc., calculate the content of the silver nanoparticles on the surface of the final fiber and quantitatively discharge the electrospray. At this time, the voltage used is the same as the electrospinning through the voltage generator or use a voltage of about 1-30kV or lower intervals and the size of the silver particles produced by electrospray is preferably 10 ~ 100nm. The distance between the electrospinning and the electrospinning (L) is preferably to be within 5 ~ 100㎝ to prevent electrical defects and the distance between the spinneret and the current collector can be used to match or adjust the electrospinning.

The present invention is characterized by including such an electrospinning and electrospinning process, characterized in that the nanoparticles are uniformly dispersed on the surface of the nanofibers through the electrospinning and electrospinning method.

In addition, the silver nanoparticles are strongly bound by electrostatic attraction (Van der Walls force) formed between the electrosprayed silver nanoparticles and the surface of the nanofibers, so that the silver nanoparticles are not easily detached.

On the other hand, the present invention may be attached to the filter nonwoven fabric filter in addition to the silver nanoparticle-containing nanofiber filter media.

The filter nonwoven media filter 10 is placed on the surface of the nanofibrous layer of the filter nonwoven media filter formed with the nanofiber layer 80 containing silver nanoparticles so that the nanofiber layer containing silver nanoparticles is sandwiched between the two filter nonwoven media filters. (FIG. 2), it is preferable to form and transport it to the crimping | compression-bonding process 60. At this time, the calendering process may be used by heating or pressing at room temperature depending on the material used, the temperature during the pressing is preferably in the range of room temperature ~ 350 ℃. The filter nonwoven media used above and below the nanofiber layer may be the same or different.

As described above, by simultaneously performing the electrospinning and electrospraying method on the filter nonwoven filter media, the nano nanoparticles are uniformly dispersed on the surface of the nanofiber layer, thereby producing a high performance filter media with a simple and inexpensive process.

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 1

Polyvinyl alcohol (polyvinylachol, PVA) having a molecular weight of 1500 was dissolved in distilled water at 80 ° C. at a concentration of 10% by weight, and then cooled to room temperature to prepare a spinning solution. Electrospinning was performed on the nonwoven fabric for polyprppylene (PP) filters with a porosity of 80% and a thickness of 150 µm using a voltage of 25 kV, a distance of 15-25 cm from the spinneret and a current collector, and a 0.5 mm diameter of the nozzle. It was. An electron micrograph of the electrospun PVA nanofibers is shown in FIG. 3. A 1 wt% silver nanopowder was sonicated in a solution of 1: 1 mixed distilled water and acetone on the nanofibrous layer electrospun on the nonwoven fabric filter for PP filter, and the uniformly dispersed solution was electrosprayed through a nozzle having a diameter of 0.5 mm. The voltage used was 20 kV, and the distance between the current collector and the spinneret was 15-25 cm, which was fixed to match the PVA electrospinning. The distance between the electrospinning and the electrospinning was carried out at 15 cm. If the distance between electrospinning and electrospray is too long, that is, more than 1m away, there is no overlapping section of electric field by electrospinning and electrospray, so synergistic effect of voltage used for electrospinning and electrospray cannot be obtained. It is effective to carry out the distance of electrospinning and electrospray within 5-100cm. At this time, the feed rate of the current collector was 1 ~ 10m per minute, the temperature of the calendar was carried out at room temperature.

Example 2

Molecular weight 180,000 polyacrylonitrile (PAN) was dissolved in a solvent DMAc 60 ℃ 15% by weight and then electrospinning was carried out in the same manner as in Example 1. At this time, the composition of the solution in which the silver nanopowders used were dispersed was the same as in Example 1.

Example 3

In the same manner as in Example 2, the silver nanoparticle solution was carried out using acetone in a 1: 1 ratio in DMAc. A transmission electron micrograph of PAN nanofibers containing 1 wt% silver nanoparticles is shown in FIG. 4. As shown in the photograph, it was confirmed that the silver nanoparticles were uniformly dispersed on the surface.

Example 4

A polybutylene terephthalate (PBT) resin was dissolved in tetrafluoroacetic acid (TFA) at 10% by weight to prepare a spinning solution, and electrospinning in the same manner as in Example to prepare a nanofiber layer. An electron micrograph of the prepared nanofibers is shown in FIG. 5. Electrospray method was also the same as in the above example, wherein the solvent was carried out using a TFA solution containing 50% by weight of acetone.

[Test Examples 1,2]

In addition, the antimicrobial activity and filter effect of the antimicrobial fiber of the present invention prepared according to the embodiment was evaluated.

Antimicrobial experiments were measured using the strains Staphyllococcus aureus and Klebsiella pneumoniae and left for 24 hours to determine the bactericidal rate (%), after removing the fibrous fibers for the convenience of the experiment was evaluated only with nanofibers (Fig. 6b). Table 1 shows the antimicrobial test results of the antimicrobial nanofibers and the control bacterium prepared by Example 2 of the present invention, the control bacterium using the antimicrobial nanofibers containing silver nanoparticles compared to about 5 times the bacteria increase It was found that the complete bactericidal rate was obtained.

Remarks Before the test 24 hours later Eradication Rate (%) Coliform 1.5 × 10 ⁵ 6.5 × 10 ⁶ - Test Example 1 (Staphyllococcus aureus) 1.5 × 10 ⁵ <10 99.9 Test Example 2 (Klebsiella pneumoniae) 1.5 × 10 ⁵ <10 99.9

Antibacterial test results (strain: Staphyllococcus aureus ATCC 6538, Klebsiella penumoniae ATCC 4325).

[Test Example 3]

The filter performance was measured with the silver nano-containing nanofiber filter medium prepared by the method of Example 3, and the thickness of the nanofiber layer was prepared by controlling the feed rate of the current collector. The performance of filter media was measured using the TSI 3160 Fractional Efficiency Filter Tester under the following conditions. The measured aerosol particles: 0.3 μm DOP, flow rate: 32 L / min, sample size: 100 cm 2, and the porosity measurement was performed using Mercury porosimetry (AutoPore IV9500) to evaluate the total porosity of the filter media at a pressure of 20 ~ 61000psi.

Table 2 shows the results of evaluating the performance and porosity of the nanofiber filter media used in this example.

sample Media thickness (㎛) Nano Fiber Thickness (㎛) Overall thickness (㎛) Collection efficiency Air resistance (mmH ₂ O) Porosity (%) One 150 10 300 97.945 6 78 2 150 30 320 98.598 10 71 3 150 50 340 99.739 17 65 4 150 70 360 99.945 28 51 5 150 90 380 99.999 42 35

As shown in Table 2, the thicker the non-woven filter medium is, the better the filter performance is, but the resistance to airflow increases and the porosity decreases. Therefore, the porosity of the filter nonwoven fabric medium is preferably about 10 to 80%.

As in the present embodiment, it was found that the nanofibers were directly electrospun on the filter nonwoven fabric media and the silver nanoparticles were uniformly dispersed by electrospraying to simultaneously have antimicrobial and excellent filter characteristics.

As described above, according to the present invention, by performing the electrospinning and electrospraying together, it is possible to uniformly disperse the silver nanoparticles on the surface of the nanofiber layer to produce a nanofiber filter media having excellent antibacterial and bactericidal power It can be effective.

In addition, by electrospinning the nanofiber forming polymer solution directly on the substrate, the bending and cutting efficiency of the nanofiber filter media can be improved, and the nanofiber layer is laminated between the two substrates, thereby preventing the loss of silver nanoparticles and The life of the media is extended to increase the water quality and atmospheric purification efficiency.

Claims (10)

a) electrospinning the nanofiber forming polymer solution on the filter nonwoven media to form a nanofiber layer; b) a method of manufacturing silver nanoparticle-containing nanofiber filter media comprising electrospraying a silver nanoparticle-containing solution on the surface of the nanofiber layer to disperse the silver nanoparticles on the surface of the nanofiber layer. . The method according to claim 1, Step a) and step b) is a manufacturing method of the silver nanoparticle-containing nanofiber filter media, characterized in that carried out continuously in a roll process. The method according to claim 1, The method of manufacturing a silver nanoparticle-containing nanofiber filter media, characterized in that further comprising the step of attaching a filter non-woven filter medium on the surface of the nanofiber layer in which the silver nanoparticles are dispersed. The method according to claim 1, In step a), the nanofiber forming polymer solution is electrospinned by a spinning nozzle subjected to high voltage, In the step b), the silver nanoparticle-containing nanofiber filter media manufacturing method characterized in that the electrospray of the silver nanoparticle-containing solution by a spray nozzle subjected to a high voltage. The method according to claim 4, The concentration of the nanofiber forming polymer solution is a method for producing a silver nanoparticle-containing nanofiber filter media, characterized in that 10 to 50% by weight. The method according to claim 4, The concentration of the silver nanoparticle-containing solution is 0.001 to 10% by weight, characterized in that the manufacturing method of the silver nanoparticle-containing nanofiber filter media. The method according to claim 1, The filter nonwoven media is at least one member selected from the group consisting of polyester, polyvinyl, polyvinyl alcohol, polyacrylonitrile, polyolefin, polypropylene, carbon and activated carbon fibers. Process for producing nanofiber filter media containing silver nanoparticles. The method according to claim 1, The method of manufacturing a nano-fiber filter media containing silver nanoparticles, characterized in that the diameter of the nanofiber layer is 100 ~ 1000nm. The method according to claim 1, The silver nanoparticles dispersed on the surface of the nanofiber layer is a method for producing a silver nanoparticle-containing nanofiber filter media, characterized in that contained in 0.005 to 10% by weight relative to the weight of the nanofiber layer. The silver nanoparticle-containing nanofiber filter media produced by the manufacturing method according to any one of claims 1 to 14.

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