JP2009249750A - Nanofiber production apparatus and nanofiber production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce nanofibers, while explosions caused by solvent vapor are prevented. <P>SOLUTION: Provided is a nanofiber production apparatus comprising outflow means 201 that causes the outflow of a starting material liquid 300 into a space, a first charging means 202 for imparting an electrostatic charge to the starting material liquid 300, a guiding means 206 for forming wind tunnels for guiding the produced nanofibers 301, a gas flow generating means 203 that generates a gas flow for transporting the nanofibers into the guiding means 206, a scattering means 240 for scattering the nanofibers 301 guided by the guiding means 206, a collection device for electrically pulling together and collecting the nanofibers 301, and a suction means 102 for sucking vaporized components evaporated from the starting material liquid 300 and the gas flow. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a nanofiber manufacturing apparatus that manufactures nanofibers using an electrospinning method (electrostatic explosion), and more particularly to a nanofiber manufacturing apparatus and a nanofiber manufacturing method that can safely manufacture nanofibers.

  An electrospinning (charge-induced spinning) method is known as a method for producing a filamentous (fibrous) material (nanofiber) made of a polymer material or the like and having a submicron-scale diameter.

  In this electrospinning method, a raw material liquid in which a polymer substance or the like is dispersed or dissolved in a solvent is ejected (discharged) into the space by a nozzle or the like, and the raw material liquid is charged and charged to fly through the space. This is a method for obtaining nanofibers by electrostatically exploding the raw material liquid therein.

  More specifically, the volume of the raw material liquid is reduced as the solvent evaporates from the particles of the raw material liquid in flight through the space. On the other hand, the charge imparted to the raw material liquid remains in the raw material liquid. As a result, the charge density of the particles of the raw material liquid flying in the space increases. Since the solvent in the raw material liquid continues to evaporate, the charge density of the raw material liquid grains further increases, and the coulomb force in the repulsive direction generated in the raw material liquid grains exceeds the surface tension of the raw material liquid. When this occurs, a phenomenon (electrostatic explosion) occurs in which the polymer solution is stretched linearly explosively. The electrostatic explosions occur one after another in the space, and nanofibers made of a polymer having a submicron diameter are manufactured.

  The solvent constituting the raw material liquid used in the above method is required to volatilize easily. As the liquid having such properties, organic solvents such as availability and cost are typical, but many of them are flammable. Therefore, an explosion-proof measure that does not explode the evaporated solvent is an important issue.

Therefore, an invention is disclosed in which the space where the solvent evaporates is closed, and oxygen causing the explosion is removed from the space by filling the space with an inert gas such as nitrogen (for example, patent document). 1).
Japanese Patent Laid-Open No. 2-273656

  However, if the solvent is evaporated in a sealed space, the density of the solvent in the space increases, and the solvent is difficult to evaporate from the raw material liquid. In the case of the coating described in Patent Document 1, the evaporation of the solvent may not be a big problem. However, when the nanofiber is manufactured, if the evaporation of the solvent is slow, the electrostatic explosion is less likely to occur. The problem is that the diameter of the nanofiber is large and the required amount of nanofiber is not generated.

  The present invention has been made in view of the above problems, and provides a nanofiber manufacturing apparatus and a nanofiber manufacturing method capable of manufacturing nanofibers in an explosion-proof state without inhibiting evaporation of the solvent from the raw material liquid. With the goal.

  In order to achieve the above object, a nanofiber manufacturing apparatus according to the present invention includes: an injection unit that injects a raw material liquid that is a raw material of a nanofiber into a space; The charging means, the guiding means for forming a wind tunnel for guiding the manufactured nanofibers, the gas flow generating means for generating a gas flow for conveying the nanofibers inside the guiding means, and the guiding means guide Diffusion means for diffusing nanofibers, collection means for collecting the nanofibers using a polarity opposite to the charging polarity of the nanofibers, and suction means for sucking the gas flow together with the evaporated components evaporated from the raw material liquid It is characterized by providing.

  Thereby, since the raw material liquid evaporates in the gas flow in the nanofiber manufacturing apparatus and electrostatic explosion occurs, the volatile solvent is sucked into the suction means without staying. Accordingly, since the nanofiber can be manufactured while maintaining the concentration not exceeding the explosion limit inside the guide means, high explosion-proof performance can be obtained.

  Furthermore, it is desirable to include second charging means for charging the nanofibers conveyed by the gas flow with the same polarity as the charging polarity of the nanofibers.

  Thereby, the nanofiber which has been transported and is weakly charged or electrically neutral can be charged again, and the nanofiber can be easily attracted by the collecting electrode.

  Furthermore, a compression means for compressing a space where the nanofibers conveyed by the gas flow are present and increasing a density where the nanofibers exist in the space may be provided.

  According to this, it is possible to increase the uniformity of the spatial distribution of the nanofibers by increasing the spatial density of the nanofibers by the compression unit and then diffusing at once by the diffusion unit.

  The raw material liquid preferably contains a polymer resin constituting the nanofiber in a ratio of 1 vol% or more and less than 50 vol% and an organic solvent as an evaporating solvent in a ratio of 50 vol% or more and less than 99 vol%.

  As a result, even if the raw material liquid contains 50 vol% or more of the solvent as described above, it is possible to sufficiently evaporate and generate an electrostatic explosion. Therefore, since the nanofiber is manufactured from a state in which the polymer as a solute is thin, it is possible to manufacture a thinner nanofiber. Moreover, since the adjustable range of the raw material liquid is expanded, the range of the performance of the manufactured nanofiber can be increased.

  In order to achieve the above object, a nanofiber manufacturing method according to the present invention includes a spraying step of spraying a raw material liquid, which is a raw material of nanofibers, into a space, and a method of charging by charging the raw material liquid. One charging step, a transport step for generating a gas flow and transporting the nanofibers by the generated gas flow, a diffusion step for diffusing the transported nanofibers, and the nanofibers in a diffused state of the nanofibers. It includes a collection step of collecting using a polarity opposite to the charging polarity, and a suction step of sucking the gas flow together with the evaporated component evaporated from the raw material liquid.

  Further, a second charging step of charging the nanofibers conveyed by the gas flow with the same polarity as the charging polarity of the nanofibers may be included.

  Furthermore, a compression step of compressing a space where the nanofibers conveyed by a gas flow are present and increasing a density where the nanofibers exist in the space may be included.

  By adopting the above method, it is possible to achieve the same effects as described above.

  According to the present invention, it is possible to manufacture nanofibers with high efficiency while maintaining high safety against explosion.

  Next, an embodiment of a nanofiber manufacturing apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a nanofiber manufacturing apparatus according to an embodiment of the present invention.

  As shown in the figure, the nanofiber manufacturing apparatus 100 includes a discharge means 200, a guide means 206, a compression means 230, a diffusion means 240, a collection means 110, a second charging means 207, and a suction means 102. I have.

  The ejection unit 201, the first charging unit 202, the wind tunnel body 209, and the gas flow generation unit 203 constitute a discharge unit 200. The discharge unit 200 includes the charged raw material liquid 300 and the nanofiber 301 to be manufactured. It is a unit that can be discharged in a gas flow. The discharge means 200 will be described in detail later.

  Here, the raw material liquid for manufacturing the nanofiber is referred to as a raw material liquid 300, and the manufactured nanofiber is referred to as a nanofiber 301. Since it changes, the boundary between the raw material liquid 300 and the nanofiber 301 is ambiguous and cannot be clearly distinguished.

  The guide means 206 is a conduit that forms a wind tunnel that guides the manufactured nanofiber 301 to a predetermined location. In the case of this embodiment, the compressing means 230 and the diffusing means 240 described later are also included in the guiding means 206 in the sense that the nanofiber 301 is guided.

  The compression unit 230 is a device having a function of compressing a space (inner portion of the guide unit 206) where the nanofibers 301 conveyed by the gas flow are present and increasing the density of the nanofibers 301 in the space. The second gas flow generating means 232 and the compression conduit 234 are provided.

  The compression conduit 234 is a cylindrical member that gradually narrows the space in which the nanofibers 301 conveyed inside the guide means 206 exist, and the gas flow generated by the second gas flow generation means 232 is compressed into the compression conduit. The peripheral wall is provided with a gas flow inlet 233 that can be introduced inwardly. The portion of the compression conduit 234 connected to the guide means 206 has an area corresponding to the area of the lead-out end of the guide means 206, and the lead-out end of the compression conduit 234 corresponds to the lead-out end. It is smaller than the area. Therefore, the compression conduit 234 has a funnel shape as a whole, and the nanofiber 301 introduced into the compression conduit 234 can be compressed together with the gas flow.

  In addition, the end shape on the upstream side (introduction side) of the compression unit 230 is an annular shape that matches the end shape of the guide unit 206. On the other hand, the end shape on the downstream side (discharge side) of the compression unit 230 is a rectangle. Further, the end portion shape on the downstream side (discharge side) of the compression unit 230 extends over the entire width direction (perpendicular to the paper surface of the drawing) of the deposition unit 101, and the length corresponding to the moving direction of the deposition unit 101 is , Narrow in the width direction. The shape of the compression means 230 gradually changes from the annular upstream end toward the rectangular downstream.

  The second gas flow generation means 232 is a device that generates a gas flow by introducing a high-pressure gas into the compression conduit 234. In the present embodiment, the second gas flow generating means 232 employs an apparatus that includes a tank (cylinder) that can store high-pressure gas and a gas outlet means that includes a valve 235 that adjusts the pressure of the high-pressure gas in the tank. ing.

  The second charging unit 207 is attached to the inner wall of the compression unit 230 and has a function of enhancing the charging of the charged nanofiber 301 or charging the neutralized nanofiber 301. It is. For example, an apparatus capable of emitting ions or particles having the same polarity as the charged nanofiber 301 into the space can be listed. Specifically, the second charging means 207 comprising an arbitrary system such as a corona discharge system, a voltage application system, an AC system, a steady DC system, a pulse DC system, a self-discharge system, a soft X-ray system, an ultraviolet system, and a radiation system is provided. May be adopted.

  The diffusing unit 240 is a conduit that is connected to the compressing unit 230 and diffuses and disperses the nanofibers 301 that have been compressed at one end and are in a high density state. The hood that decelerates the speed of the nanofibers 301 accelerated by the compressing unit 230. Shaped member. The diffusion means 240 includes a rectangular opening on the upstream end side into which the gas flow is introduced and a rectangular opening on the downstream end side from which the gas flow is discharged, and the opening area of the opening on the downstream end side is upstream. It is set to be larger than the opening area of the opening on the end side. The diffusing means 240 has a shape that gradually increases in area from the opening on the upstream end side toward the opening on the downstream end side. The opening on the downstream end side has a width larger than the width of the deposition unit 101 and has a shape longer than the collection electrode 112 described later.

  When the gas flow flows from the small area introduction end side of the diffusing means 240 toward the large area lead-out end side, the nanofibers 301 in a high density state are dispersed in a low density state at once, and the flow velocity of the gas flow is It falls in proportion to the cross-sectional area of the diffusing means 240. Therefore, the speed of the nanofiber 301 carried on the gas flow is reduced along with the gas flow. At this time, the nanofiber 301 gradually and uniformly diffuses as the cross-sectional area of the diffusing means 240 increases. Accordingly, the nanofibers 301 can be uniformly deposited on the deposition means 101. In addition, since the nanofiber 301 is not transported by the gas flow, that is, the gas flow and the nanofiber 301 are separated, the charged nanofiber 301 has a reverse polarity without being affected by the gas flow. It is attracted to the collecting electrode 112 in the state.

  The collecting unit 110 is a device for collecting the nanofibers 301 emitted from the diffusing unit 240, and includes a deposition unit 101, a transfer unit 104, a collecting electrode 112, and a collecting power source 113.

  The depositing means 101 is a member on which nanofibers 301 that are manufactured by electrostatic explosion and fly are deposited. The deposition means 101 is a thin and flexible long sheet-like member made of a material that can be easily separated from the deposited nanofibers 301. Specifically, as the deposition means 101, a long cloth made of aramid fibers can be exemplified. Furthermore, it is preferable to perform a Teflon (registered trademark) coating on the surface of the deposition unit 101 because the peelability when the deposited nanofiber 301 is peeled off from the deposition unit 101 is improved. Further, the deposition means 101 is supplied from the supply roll 111 in a state of being wound in a roll shape.

  The transfer means 104 pulls out the long deposition means 101 from the supply roll 111 while winding it, and conveys the deposition means 101 together with the nanofibers 301 to be deposited. The transfer means 104 is capable of winding the nanofiber 301 deposited in a nonwoven fabric shape together with the deposition means 101.

  The collection electrode 112 is a member that attracts the charged nanofibers 301 by an electric field (electric field), and is a rectangular plate-like electrode that is slightly smaller than the opening at the downstream end of the diffusion means 240. In the state where the collection electrode 112 is disposed in the opening of the diffusing unit 240, a gap is generated between the diffusing unit 240 and the collecting electrode 112. The peripheral edge of the surface of the collecting electrode 112 facing the diffusing means 240 does not have a sharp portion, and is rounded as a whole to prevent abnormal discharge from occurring.

  The collection power supply 113 is a power supply for applying a potential to the collection electrode 112, and a DC power supply is employed in the present embodiment.

  The suction unit 102 is a device that is disposed in the gap between the diffusion unit 240 and the collection electrode 112 and forcibly sucks the gas flow that is separated from the nanofiber 301 and flows out of the gap. In the present embodiment, a blower such as a sirocco fan or an axial fan is employed as the suction unit 102. Further, the suction unit 102 can suck most of the gas stream mixed with the solvent evaporated from the raw material liquid 300 and can transport the gas stream to the solvent recovery device 106 connected to the suction unit 102. Yes.

  FIG. 2 is a cross-sectional view showing the discharging means.

  FIG. 3 is a perspective view showing the discharging means.

  The discharge unit 200 includes an ejection unit 201, a first charging unit 202, a wind tunnel body 209 (guide unit 206), and a gas flow generation unit 203.

  As shown in these drawings, the injection means 201 is an apparatus that injects the raw material liquid 300 into the space. In the present embodiment, the injection means 201 is an apparatus that injects the raw material liquid 300 radially by centrifugal force. The injection unit 201 includes an injection container 211, a rotating shaft body 212, and a motor 213.

  The injection container 211 is a container that can inject the raw material liquid 300 into the space by centrifugal force due to its rotation while the raw material liquid 300 is injected inward, and has a cylindrical shape with one end closed. Has a number of injection ports 216. The injection container 211 is formed of a conductor in order to give a charge to the stored raw material liquid 300. The injection container 211 is rotatably supported by a bearing (not shown) provided on a support (not shown).

  Specifically, it is preferable that the diameter of the ejection container 211 is adopted from a range of 10 mm to 200 mm. It is because it will become difficult to concentrate the raw material liquid 300 and the nanofiber 301 by a gas flow if too large. On the other hand, if it is too small, the rotation for injecting the raw material liquid 300 by centrifugal force must be increased, and problems such as motor load and vibration occur. Furthermore, it is preferable to employ the diameter of the injection container 211 from the range of 20 mm or more and 80 mm or less. Moreover, the shape of the injection port 216 is preferably circular, and the diameter is preferably employed from a range of 0.01 mm to 2 mm.

  Note that the shape of the ejection container 211 is not limited to a cylindrical shape, and may be a polygonal column shape having a polygonal side surface or a conical shape. It is only necessary that the raw material liquid flows out of the injection port 216 by centrifugal force by rotating the injection port 216.

  The rotation shaft body 212 is a shaft body for transmitting a driving force for rotating the injection container 211 and injecting the raw material liquid 300 by centrifugal force, and is inserted into the injection container 211 from the other end of the injection container 211. This is a rod-like body in which the closing portion and one end portion of the injection container 211 are joined. The other end is joined to the rotating shaft of the motor 213.

  The motor 213 is a device that applies a rotational driving force to the injection container 211 via the rotary shaft body 212 in order to inject the raw material liquid 300 from the injection port 216 by centrifugal force. The number of revolutions of the injection container 211 is selected from a range of several rpm or more and 10,000 rpm or less depending on the diameter of the injection port 216, the viscosity of the raw material liquid 300 to be used, the type of polymer substance in the raw material liquid, and the like. It is preferable that when the motor 213 and the ejection container 211 are linearly moved as in the present embodiment, the rotational speed of the motor 213 matches the rotational speed of the ejection container 211.

  The first charging means 202 is a device that charges the raw material liquid 300 by applying an electric charge. In the present embodiment, the first charging unit 202 includes an induction electrode 221, an induction power source 222, and a grounding unit 223. The ejection container 211 also functions as a part of the first charging unit 202.

  The induction electrode 221 is a member for inducing electric charge to the injection container 211 that is arranged in the vicinity and grounded when the induction electrode 221 has a high voltage with respect to the ground, and is arranged so as to surround the distal end portion of the injection container 211. It is an annular member. The induction electrode 221 also functions as a wind tunnel body 209 that guides the gas flow from the gas flow generation unit 203 to the guide unit 206.

  The size of the induction electrode 221 needs to be larger than the diameter of the ejection container 211, and the diameter is preferably adopted from a range of 200 mm or more and 800 mm or less.

  The induction power supply 222 is a power supply that can apply a high voltage to the induction electrode 221. In general, the induction power supply 222 is preferably a DC power supply. In particular, a direct current power source is preferable when the charged polarity of the nanofiber 301 to be generated is not affected, or when the charged nanofiber 301 is collected and collected on the electrode. In addition, when the induction power supply 222 is a DC power supply, the voltage applied by the induction power supply 222 to the induction electrode 221 is preferably set from a value in the range of 10 KV or more and 200 KV or less. In particular, the electric field strength between the ejection container 211 and the induction electrode is important, and it is preferable to arrange the applied voltage and the induction electrode 221 so that the electric field strength is 1 KV / cm or more. The shape of the induction electrode 221 is not limited to an annular shape, and may be a polygonal annular member having a polygonal shape.

  The grounding means 223 is a member that is electrically connected to the ejection container 211 and can maintain the ejection container 211 at a ground potential. One end of the grounding means 223 functions as a brush so that an electrical connection state can be maintained even when the injection container 211 is in a rotating state, and the other end is connected to the ground.

  If the induction method is adopted for the first charging means 202 as in the present embodiment, it is possible to apply a charge to the raw material liquid 300 while maintaining the injection container 211 at the ground potential. If the injection container 211 is in a ground potential state, it is not necessary to electrically insulate members such as the rotary shaft 212 and the motor 213 connected to the injection container 211 from the injection container 211, and the structure of the injection unit 201 is simple. Can be adopted, which is preferable.

  In addition, as the first charging unit 202, a charge may be applied to the raw material liquid 300 by connecting a power source to the injection container 211, maintaining the injection container 211 at a high voltage, and grounding the induction electrode 221. In addition, the injection container 211 is formed of an insulator, and an electrode that is in direct contact with the raw material liquid 300 stored in the injection container 211 is disposed inside the injection container 211, and an electric charge is applied to the raw material liquid 300 using the electrode. It may be a thing.

  The gas flow generation unit 203 is a device that generates a gas flow for changing the flight direction of the raw material liquid 300 injected from the injection container 211 to the direction guided by the guide unit 206. The gas flow generation means 203 is provided on the back of the motor 213 and generates a gas flow from the motor 213 toward the tip of the injection container 211. The gas flow generation means 203 can generate wind power that can change the raw material liquid 300 in the axial direction until the raw material liquid 300 injected in the radial direction from the injection container 211 reaches the induction electrode 221. It has become. In FIG. 2, the gas flow is indicated by arrows. In the case of the present embodiment, a blower including an axial fan that forcibly blows the atmosphere around the discharge unit 200 is employed as the gas flow generation unit 203.

  Note that the gas flow generating means 203 may be constituted by another blower such as a sirocco fan. Moreover, the direction of the injected raw material liquid 300 may be changed by introducing high-pressure gas. Further, a gas flow may be generated inside the guide unit 206 by the suction unit 102, the second gas flow generation unit 232, or the like. In this case, the gas flow generation means 203 does not have a device that actively generates a gas flow. However, in the case of the present invention, the gas flow generation occurs when the gas flow is generated inside the guide means 206. It is assumed that the means 203 exists. In addition, the gas flow generating means may exist so that the gas flow is generated inside the guide means 206 by being sucked by the suction means 102 without the gas flow generating means 203. To do. In addition, the gas flow generating means may exist so that the gas flow is generated inside the guide means 206 by being sucked by the suction means 102 without the gas flow generating means 203. To do.

  The wind tunnel body 209 is a conduit that guides the gas flow generated by the gas flow generation means 203 to the vicinity of the injection container 211. The gas flow guided by the wind tunnel body 209 intersects the raw material liquid 300 injected from the injection container 211, and changes the flight direction of the raw material liquid 300.

  Furthermore, the discharge unit 200 includes a gas flow control unit 204 and a heating unit 205.

  The gas flow control means 204 has a function of controlling the gas flow so that the gas flow generated by the gas flow generation means 203 does not hit the injection port 216. In this embodiment, as the gas flow control means 204, An air passage body that guides the gas flow so as to flow in a predetermined region is employed. Since the gas flow does not directly hit the injection port 216 by the gas flow control means 204, the raw material liquid 300 injected from the injection port 216 is prevented from evaporating at an early stage and blocking the injection port 216 as much as possible. The liquid 300 can be stably sprayed continuously. The gas flow control means 204 may be a wall-shaped windbreak wall that is arranged on the windward side of the injection port 216 and prevents the gas flow from reaching the vicinity of the injection port 216.

  The heating unit 205 is a heating source that heats the gas constituting the gas flow generated by the gas flow generation unit 203. In the case of the present embodiment, the heating means 205 is an annular heater arranged inside the guide means 206 and can heat the gas passing through the heating means 205. By heating the gas flow by the heating means 205, the raw material liquid 300 injected into the space is promoted to evaporate, and nanofibers can be manufactured efficiently.

  Next, the manufacturing method of the nanofiber 301 using the nanofiber manufacturing apparatus 100 of the said structure is demonstrated.

  First, a gas flow is generated inside the guide unit 206 and the wind tunnel body 209 by the gas flow generation unit 203 and the second gas flow generation unit 232. On the other hand, the gas flow generated in the guide means 206 is sucked by the suction means 102.

  Next, the raw material liquid 300 is supplied to the injection container 211 of the injection unit 201. The raw material liquid 300 is separately stored in a tank (not shown), passes through a supply path 217 (see FIG. 2), and is supplied from the other end of the injection container 211 into the injection container 211.

  Next, while the charge is supplied to the raw material liquid 300 stored in the injection container 211 by the induction power supply 222 (first charging step), the injection container 211 is rotated by the motor 213 and charged from the injection port 216 by centrifugal force. The raw material liquid 300 is injected (injection process).

  The raw material liquid 300 injected radially in the radial direction of the injection container 211 is changed in flight direction by the gas flow and is guided by the wind tunnel body 209 in the gas flow. The raw material liquid 300 is discharged from the discharge means 200 while manufacturing the nanofiber 301 by the electrostatic explosion (nanofiber manufacturing process). The gas flow is heated by the heating means 205, and heats the raw material liquid 300 to promote the evaporation of the solvent while guiding the flight of the raw material liquid 300. The nanofibers 301 emitted from the emission means 200 as described above are conveyed by the gas flow inside the guide means 206 (conveying process).

  Next, the nanofiber 301 passing through the inside of the compression unit 230 is accelerated by the jet of high-pressure gas, and is gradually compressed as the inside of the compression unit 230 becomes narrower and reaches a diffusion unit 240 in a high density state. (Compression process).

  Here, since the nanofiber 301 carried by the gas flow until now may be weakly charged, the second charging means 207 forcibly charges the nanofiber 301 with the same polarity (second charging). Process).

  The nanofibers 301 transported to the diffusion means 240 are rapidly reduced in speed and uniformly dispersed (diffusion process).

  In this state, the collecting electrode 112 disposed in the opening of the diffusing unit 240 is charged with a polarity opposite to the charged polarity of the nanofiber 301, and thus attracts the nanofiber 301. Since the deposition means 101 exists between the nanofiber 301 and the collection electrode 112, the nanofiber 301 attracted to the collection electrode 112 is deposited on the deposition means 101 (collection process).

  On the other hand, the suction means 102 disposed in the vicinity of the gap between the collecting electrode 112 and the diffusing means 240 sucks the gas flow together with the solvent as the evaporated component (suction process).

  As described above, the evaporation of the solvent contained in the raw material liquid 300 occurs inside the guide unit 206, but the inside of the guide unit 206 always flows until a gas flow exists and is sucked into the suction unit 102 and collected. Therefore, the vapor of the solvent does not stay inside the guide means 206. Therefore, the inside of the guide means 206 does not exceed the explosion limit, and the nanofiber 301 can be manufactured while maintaining a safe state.

  Furthermore, since it is possible to use a flammable solvent, the range of types of organic solvents that can be used as the solvent is widened, and it is also possible to select an organic solvent that has little adverse effect on the human body as the solvent. . It is also possible to improve the production efficiency of the nanofibers 301 by selecting an organic solvent having a high evaporation efficiency as the solvent.

  Further, since the nanofiber 301 is uniformly diffused and dispersed by the diffusion means 240 and then attracted by the collecting electrode 112, the nanofiber 301 is uniformly deposited on the deposition means 101. Therefore, when using the deposited nanofiber 301 as a nonwoven fabric, it is possible to obtain a nonwoven fabric with stable performance over the entire surface. In addition, even when the deposited nanofiber 301 is spun, it is possible to obtain a yarn with stable performance.

  Here, as a polymer substance constituting the nanofiber 301, polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, Polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, nylon, aramid , Polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, polypep The de like. Moreover, the kind selected from the above may be used, and a plurality of kinds may be mixed. Note that the above is an example, and the present invention is not limited to the above polymer substance.

  Solvents used for the raw material liquid 300 include methanol, ethanol, 1-propanol, 2-propanol, hexafluoroisopropanol, tetraethylene glycol, triethylene glycol, dibenzyl alcohol, 1,3-dioxolane, 1,4-dioxane. , Methyl ethyl ketone, methyl isobutyl ketone, methyl n-hexyl ketone, methyl n-propyl ketone, diisopropyl ketone, diisobutyl ketone, acetone, hexafluoroacetone, phenol, formic acid, methyl formate, ethyl formate, propyl formate, methyl benzoate, Ethyl benzoate, propyl benzoate, methyl acetate, ethyl acetate, propyl acetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, methyl chloride, ethyl chloride, methylene chloride, chloroform , O-chlorotoluene, p-chlorotoluene, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane, dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethyl bromide, odor Propyl chloride, acetic acid, benzene, toluene, hexane, cyclohexane, cyclohexanone, cyclopentane, o-xylene, p-xylene, m-xylene, acetonitrile, tetrahydrofuran, N, N-dimethylformamide, pyridine, water, etc. it can. Moreover, the kind selected from the above may be used, and a plurality of kinds may be mixed. Note that the above is an example, and the present invention is not limited to the above polymer substance.

Furthermore, an additive such as an aggregate or a plasticizer may be added to the raw material liquid 300. Examples of the additive include oxides, carbides, nitrides, borides, silicides, fluorides, sulfides, and the like. From the viewpoints of heat resistance and workability, oxides are preferably used. Examples of the oxide include Al ₂ O ₃ , SiO ₂ , TiO ₂ , Li ₂ O, Na ₂ O, MgO, CaO, SrO, BaO, B ₂ O ₃ , P ₂ O ₅ , SnO ₂ , ZrO ₂ , K. ₂ O, Cs ₂ O, ZnO, Sb ₂ O ₃ , As ₂ O ₃ , CeO ₂ , V ₂ O ₅ , Cr ₂ O ₃ , MnO, Fe ₂ O ₃ , CoO, NiO, Y ₂ O ₃ , Lu ₂ Examples thereof include O ₃ , Yb ₂ O ₃ , HfO ₂ , Nb ₂ O _{5 and the} like. Moreover, the kind selected from the above may be used, and a plurality of kinds may be mixed. Note that the above is an example, and the present invention is not limited to the above polymer substance.

  The mixing ratio of the solvent and the polymer is selected from a range of 1 vol% or more and less than 50 vol% of the polymer resin constituting the nanofiber, and correspondingly, an organic solvent that is an evaporating solvent is 50 vol% or more, It is desirable to select from a range of less than 99 vol%.

  As described above, since the solvent vapor is processed without being retained by the gas flow, the raw material liquid 300 is sufficiently evaporated even if it contains 50 vol% or more of the solvent as described above, and generates an electrostatic explosion. Is possible. Therefore, since the nanofiber 301 is manufactured from a state in which the solute polymer is thin, it is possible to manufacture a thinner nanofiber 301. Moreover, since the adjustable range of the raw material liquid 300 is widened, the performance range of the manufactured nanofiber 301 can be widened.

  In the above embodiment, the raw material liquid 300 is injected using centrifugal force, but the present invention is not limited to this. For example, as shown in FIG. 4, a large number of nozzles made of a conductive material are provided in a rectangular wind tunnel body 209, and an induction electrode 221 is provided on the opposite surface of the wind tunnel body 209 to form the first charging means 202. Further, gas flow generating means 203 is provided at the end of the wind tunnel body 209. The discharge means 200 configured as described above may be used.

  In addition, as shown in FIG. 5, a two-fluid nozzle formed of a conductive material at the end of a cylindrical wind tunnel body 209 whose one end is closed (a two-fluid nozzle is a hole that flows out the raw material liquid 300 and its hole. A hole for injecting a high-pressure gas provided in the vicinity is provided, and the high-pressure gas is sprayed on the raw material liquid 300 so that the raw material liquid 300 is sprayed. An annular induction electrode 221 is provided so as to surround the nozzle. The inner pipe of the two-fluid nozzle functions as an injection unit 201 through which the raw material liquid 300 is injected, and the outer pipe forms the raw material liquid 300 in a mist shape and is located inside the wind tunnel body 209 and the guide unit 206. It functions as gas flow generation means 203 that generates a gas flow. The discharge means 200 configured as described above may be used.

  In the present embodiment, the sending machine is exemplified as the gas flow generating means 203, but the present invention is not limited to this. For example, when an opening is provided in a necessary portion of the discharge unit 200 and suction is performed by the suction unit 102, if the surrounding atmosphere is sucked from the opening and a gas flow is generated in the guide unit 206, the opening is It becomes the gas flow generating means 203.

  Further, the compression unit 230 and the second charging unit 207 can be omitted as appropriate.

  Further, when the compression unit 230 is omitted in FIG. 1 and the guide unit 206 is directly connected to the diffusion unit 240, the effect that explosion does not occur even when a highly flammable solvent is used. can get. In particular, the concentration of the solvent in the vicinity of the deposition unit 101 can be maintained in a state where it does not reach the explosive limit of explosion caused by the solvent by disposing the suction unit 102 in the vicinity, and the generated charged nanofibers are The effect of depositing uniformly on the deposition means 101 is obtained. Further, a second charging unit may be provided on the wall surface of the guide unit 206 to further charge the charged nanofibers with the same polarity.

  Although the collecting electrode 112 is connected to the collecting power source 113, the effects described in the present invention can be obtained even when the collecting electrode 112 is grounded to collect the charged nanofibers.

  The present invention can be used for the production of nanofibers.

It is sectional drawing which shows typically the nanofiber manufacturing apparatus which is embodiment of this invention. It is sectional drawing which shows a discharge | release means. It is a perspective view which shows discharge | release means. It is sectional drawing which shows typically another example of the discharge | release means. It is sectional drawing which shows typically another example of the discharge | release means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Nanofiber manufacturing apparatus 101 Deposition means 102 Suction means 104 Transfer means 106 Solvent recovery apparatus 110 Collection means 111 Supply roll 112 Collection electrode 113 Collection power supply 200 Release means 201 Injection means 202 First charging means 203 Gas flow generation means 204 Gas flow control Means 205 Heating means 206 Guide means 207 Second charging means 209 Wind tunnel body 211 Injection container 212 Rotating shaft body 213 Motor 216 Injection port 217 Supply path 221 Induction electrode 222 Induction power supply 223 Grounding means 230 Compression means 232 Second gas flow generation means 233 Gas flow inlet 234 Compression conduit 235 Valve 240 Diffusion means 300 Raw material liquid 301 Nanofiber

Claims (8)

An injection means for injecting a raw material liquid as a raw material of the nanofiber into the space;
First charging means for charging by charging the raw material liquid;
Guiding means for forming a wind tunnel for guiding the manufactured nanofibers;
A gas flow generating means for generating a gas flow for conveying the nanofibers inside the guide means;
Diffusing means for diffusing the nanofibers guided by the guiding means;
Collecting means for collecting the nanofibers using a polarity (including ground potential; the same applies hereinafter) opposite to the charged polarity of the nanofibers;
A nanofiber manufacturing apparatus comprising: suction means for sucking the gas flow together with the evaporated component evaporated from the raw material liquid. further,
2. The nanofiber manufacturing apparatus according to claim 1, further comprising a second charging unit configured to charge the nanofiber conveyed by a gas flow with the same polarity as a charging polarity of the nanofiber. further,
The nanofiber manufacturing apparatus according to claim 1, further comprising a compressing unit that compresses a space where the nanofibers conveyed by a gas flow are present and increases a density of the nanofibers existing in the space.   The said raw material liquid contains the polymer resin which comprises the said nanofiber in the ratio of 1 vol% or more and less than 50 vol%, and the organic solvent which is an evaporating solvent in the ratio of 50 vol% or more and less than 99 vol%. Nanofiber manufacturing equipment. An injection step of injecting a raw material liquid as a raw material of the nanofiber into the space;
A first charging step of charging by charging the raw material liquid;
A transport step of generating a gas flow and transporting the nanofibers by the generated gas flow;
A diffusion step of diffusing the nanofiber to be conveyed;
A collecting step of collecting the nanofibers in a diffused state using a polarity opposite to the charged polarity of the nanofibers;
And a suction step of sucking the gas flow together with the evaporated component evaporated from the raw material liquid. further,
The nanofiber manufacturing method according to claim 5, further comprising a second charging step of charging the nanofiber conveyed by the gas flow with the same polarity as the charging polarity of the nanofiber. further,
The nanofiber manufacturing method according to claim 5, further comprising a compressing step of compressing a space where the nanofibers conveyed by a gas flow are present and increasing a density of the nanofibers existing in the space.   The said raw material liquid contains the polymer resin which comprises the said nanofiber in the ratio of 1 vol% or more and less than 50 vol%, and the organic solvent which is an evaporating solvent in the ratio of 50 vol% or more and less than 99 vol%. Nanofiber manufacturing method.

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