JP4535085B2 - Nanofiber manufacturing method and apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for producing nanofibers made of a polymer material.

  Conventionally, a charge-induced spinning method (electrospinning method) is known as a method for producing a nanofiber having a submicron-scale diameter made of a polymer material. The conventional charge-induced spinning method is configured to supply a polymer solution to a needle-like nozzle to which a high voltage is applied, and the polymer solution that flows out linearly from the needle-like nozzle is charged. As the solvent of the polymer solution evaporates, the distance between the charged charges decreases and the Coulomb force acting increases, and when the Coulomb force exceeds the surface tension of the linear polymer solution, The phenomenon that the polymer solution is stretched explosively occurs, and this phenomenon called electrostatic explosion is repeated as primary, secondary, and in some cases tertiary, so that nanofibers composed of polymers with submicron diameters are formed. It is manufactured.

  By depositing the nanofibers thus manufactured on an electrically grounded substrate, a three-dimensional thin film having a three-dimensional network can be obtained, and by forming it thicker, it has a submicron network. A highly porous web can be produced. The highly porous webs thus produced can be suitably applied to filters, battery separators, polymer electrolyte membranes and electrodes of fuel cells, etc., and by applying this highly porous web made of nanofibers, respectively. It can be expected to dramatically improve performance.

  However, in the conventional charge induction spinning method, only one to several nanofibers are produced from the tip of one nozzle, and thus there is a problem that productivity of nanofiber production does not increase. Therefore, as a method for producing a large amount of nanofibers, a method using a plurality of nozzles has been proposed (see, for example, Patent Document 1).

  The configuration of the polymer web manufacturing apparatus described in Patent Document 1 will be described with reference to FIG. 7. The liquid polymer substance in the barrel 43 is fed by the pump 44 to the spinning section 42 having a plurality of nozzles 41. The high voltage generator 45 applies a high voltage of 5 to 50 kV to the nozzle 41 and deposits the fiber discharged from the nozzle 41 on the collector 46 that is grounded or charged to a polarity different from that of the nozzle 41. At the same time, the formed web is transferred by the collector 46 to produce a polymer web. In addition, a charge distribution plate 47 is disposed near the tip of the nozzle 41 to minimize electrical interference between the nozzles 41, and a high voltage is applied between the collector 46 and the charged fiber is directed toward the collector 46. It is also described that an electric field is applied.

Further, as shown in FIGS. 8A and 8B, the spinning unit 42 is not provided with a plurality of single nozzles, but is provided with a plurality of multi-nozzles 41A including a plurality of nozzles 41. It is also disclosed that a plurality of nanofibers are generated from each nozzle 41A.
JP 2002-201559 A

  However, with the configuration shown in FIGS. 7 and 8, in order to manufacture nanofibers with higher productivity, the arrangement intervals of the nozzles 41 in the spinning section 42 and the nozzles 41 in each multi-nozzle 41 </ b> A are reduced, so When trying to increase the number of nozzles, as shown in FIG. 9, since the high molecular substances flowing out from each nozzle 41 are charged with the same polarity, they repel each other as shown by arrow F, Outflow from the nozzle 41 is hindered, the outflow direction from the nozzle 41 in the peripheral portion is directed outward, the nanofiber deposition distribution on the collector 46 is extremely small in the central portion, and is concentrated in the peripheral portion. There is a problem that a uniform polymer web cannot be produced.

  Further, when the charge distribution plate 47 is disposed in the vicinity of the tip of the nozzle 41, as shown in FIG. 10, the electric interference between the nozzles 41 is reduced and an electric field E from the charge distribution plate 47 toward the collector 46 is formed. As a result, the action of accelerating the polymer substance flowing out from each nozzle 41 toward the collector 46 can be obtained, and compared with the case of FIG. 9, the nanofiber deposition distribution in the central portion and the peripheral portion. However, there is a problem in that the arrangement pattern of the nozzles 41 is projected as it is onto the deposition distribution, so that the effect of uniformizing the deposition distribution is not exhibited.

  Further, when the arrangement density of the nozzles 41 is increased, there is a possibility that the fibers contact each other in a state where the solvent does not sufficiently evaporate, and the fibers are welded to each other. There is a problem that there is a possibility that corona discharge may occur and fibers may not be formed.

  In addition, when a large number of nozzles 41 are provided, it is difficult to uniformly supply the liquid polymer material to the nozzles 41, which causes a problem that the apparatus configuration becomes complicated and the equipment cost increases. is there. Further, in order to cause an electrostatic explosion on the liquid polymer material flowing out from the nozzle 41, it is necessary to concentrate electric charges. For this reason, each nozzle 41 is formed in a thin and long shape, but a large number of thin and long shapes. There is a problem that maintenance for always maintaining the nozzle 41 in an appropriate state is extremely difficult.

  Therefore, the applicant first fixed the rotating cylinder 53 on one side surface of the conductive cylindrical container 51 having a plurality of small holes 52 on the peripheral surface as shown in FIG. The rotating cylinder 53 is supported so as to be rotatable, and the polymer solution 50 is supplied into the rotating container 51 through the solution supply pipe 55 inserted into the rotating cylinder 53 by the polymer solution supply means 54. To rotate the rotating container 51 and charge the rotating container 51 with the first high voltage generating means 56, and the linear polymer solution flowing out from the small hole 52 is used for centrifugal force and evaporation of the solvent. A nanofiber made of a polymer material is generated by stretching by electrostatic explosion accompanied by the rotation, and is rotated by a second high voltage generating means 58 on a reflective electrode 57 disposed on one side in the axial direction of the rotating container 51. Nanophase generated by applying a voltage of the same polarity as the container 51 A third collector is connected to a conductive collector 59 that is deflected toward the other side in the axial direction of the rotating container 51 and is flowed. The high-voltage generating means 60 applies a voltage having a potential difference with respect to the electric charge of the rotating container 51 to deposit nanofibers on the collector 59 (Japanese Patent Application No. 2006-317003). Issue).

  However, in the configuration of FIG. 11, the centrifugal force acting on the polymer solution 50 pushed out from the small hole 52 of the cylindrical container 51 is always kept constant, and the polymer solution 50 flows out uniformly in a linear shape, thereby producing uniform nanofibers. In order to achieve this, the amount of the polymer solution 50 stored in the rotating container 51 is detected, and the polymer solution 50 is stored so that a substantially constant amount of the polymer solution 50 is stored in the rotating container 51. It has been found that there is a problem that the solution supply means 54 needs to be controlled with high accuracy, the configuration becomes complicated, and the cost increases.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a nanofiber manufacturing method and apparatus capable of manufacturing uniform nanofibers with a simple configuration and high productivity.

  In the method for producing nanofibers of the present invention, a polymer solution in which a polymer substance is dissolved in a solvent is supplied into a conductive rotating container having a plurality of small holes, the rotating container is rotated, and the polymer that has flowed out of the small holes In a method for producing nanofibers, in which an electric field is applied to a solution and stretched by electrostatic explosion caused by centrifugal force and evaporation of the solvent to produce nanofibers made of a polymer material, the amount of the polymer solution in the rotating vessel is When the amount exceeds a predetermined amount, the polymer solution in excess of the predetermined amount is caused to flow out of the rotating container, and the outflowing polymer solution is recovered and supplied again into the rotating container. In the present invention, in order to apply an electric field to the linear polymer solution flowing out from the small hole of the rotating container, it is high between the object or member constituting the field for generating nanofibers with the rotating container. For example, when the object or member constituting the field for generating nanofibers with the rotating container is a member such as the earth or a collector grounded to the earth, the rotating container has a ground potential. It is only necessary to apply a positive or negative high voltage to the substrate, and a positive or negative high voltage with respect to the ground potential is applied to a member such as a collector constituting a field for generating nanofibers with the rotating container. In such a case, the rotating container may be grounded. Needless to say, the small hole is not limited to a hole formed directly in the peripheral wall of the rotating container, and may be constituted by a nozzle member attached to the peripheral wall of the rotating container.

  According to this configuration, the polymer solution flows out from the small hole of the rotating container by the action of the centrifugal force, and the electric charge is charged by the applied electric field. At that time, first, the polymer solution stably flows out of the small hole and is stretched by the action of the centrifugal force. Moreover, the effect | action that an electric field interference cannot generate | occur | produce very much is acquired by rotating a rotation container. The reason for this is that when the polymer solution flows out from the adjacent small holes, it flows out by centrifugal force, so that the flowing linear directions are not parallel to each other but spread radially, causing electric field interference. It is considered difficult. In this way, since it is not affected by electric field interference, even if the small holes are arranged at high density, the holes are surely and effectively stretched, and then the diameter is narrowed and the charge is concentrated as the solvent evaporates. When the Coulomb force exceeds the surface tension, a primary electrostatic explosion occurs and the film is stretched explosively.After that, the solvent evaporates, and similarly a secondary electrostatic explosion occurs and the film is stretched explosively. In addition, a third electrostatic explosion or the like occurs, and the nanofiber made of a polymer material having a sub-micron diameter from a linear polymer solution that has flowed out from a plurality of small holes has a simple and compact configuration. It can be produced in large quantities efficiently, and the polymer solution that has flowed out of the small holes is first stretched by centrifugal force, so there is no need to make the small holes extremely small and the charge is concentrated as described above. Since it is not necessary to form a long hole in the rotating container, it is only necessary to provide a small hole in the rotating container, it can be manufactured easily and inexpensively, and maintenance can be easily performed even if a large number of small holes are provided. Since the polymer solution exceeding the fixed amount flows out of the rotating container, the amount of the polymer solution in the rotating container can always be kept constant by simply supplying a sufficient amount of the polymer solution, and from the small hole of the cylindrical container. The centrifugal force acting on the extruded polymer solution can always be kept constant, so that uniform nanofibers can be produced at all times, and the polymer solution that has flowed out is recovered and supplied again into the rotating container. Since the polymer solution is reused, the polymer solution is not wasted. Therefore, uniform nanofibers can be manufactured with high productivity while reducing the apparatus cost and the material cost.

  Further, when the rotating container is composed of a cylindrical container having a plurality of small holes on the peripheral surface and a polymer solution exceeding a predetermined amount is allowed to flow out through an annular weir provided on one side surface of the rotating container, A large amount of nanofibers can be produced uniformly at a time, high productivity can be ensured, and a polymer solution exceeding a predetermined amount can flow out through an annular weir on one side of a cylindrical container. The above effects can be achieved with a very simple configuration.

  Further, when the collecting body is arranged at a predetermined distance from the rotating container, a high voltage is applied between the rotating container and the collecting body, and the generated nanofibers are caused to flow toward the collecting body, the rotating container Nanofibers can be generated and collected on the collector by an electric field formed between the collector and the collector.

  In addition, by applying a voltage of the same polarity as the charged charge of the rotating container to the reflective electrode arranged on one side in the axial direction of the rotating container, the nanofibers during the generation process are moved to the other side in the axial direction of the rotating container When it is deflected and made to flow, the nanofiber in the generation process tries to spread radially by the action of centrifugal force, and the generated nanofiber is deflected in the axial direction of the rotating container by the reflecting electrode. Since the reflective electrode is disposed on one side that does not oppose the outflow direction of the charged polymer solution and can be easily collected within the required range, the outflow of the polymer solution is caused by the charge of the reflective electrode. Nanofibers can be manufactured stably and efficiently without being disturbed, and even if droplets that do not become fibers are generated, they are scattered by the centrifugal force as they are, and only appropriate nanofibers are biased. To flowing in can be collected only good nanofibers quality.

  In addition, if the nanofibers in the production process are deflected toward the other side in the axial direction of the rotating container by flowing from one side in the axial direction of the rotating container and flowing, the evaporated solvent is quickly discharged and the surroundings The solvent concentration in the atmosphere is not increased, the solvent is smoothly evaporated, the electrostatic explosion action is reliably obtained, the desired nanofiber is reliably generated, and the flow direction of the nanofiber during the generation process is determined. It can be deflected effectively.

  In addition, the nanofiber manufacturing apparatus of the present invention includes a conductive rotating container that is rotatably supported and has a plurality of small holes at radial distances from the rotating shaft core, and a polymer as a solvent in the rotating container. Polymer solution supply means for supplying a polymer solution in which a substance is dissolved, and when the amount of the polymer solution in the rotating container exceeds a predetermined amount, the polymer solution exceeding the predetermined amount is caused to flow out of the rotating container. Means, collecting means for collecting the flowing polymer solution and supplying it to the polymer solution supply means, rotation driving means for rotating the rotating container, and first high voltage generating means for applying a high voltage to the rotating container And a controller for controlling the rotation drive means, the first voltage generation means, and the polymer solution supply means.

  According to this configuration, the polymer solution is supplied into the rotating container by the polymer solution supplying means, rotated by the rotation driving means, and a high voltage is applied to the rotating container by the first high voltage generating means. As described above, nanofibers can be efficiently produced in large quantities with a simple and compact configuration, and a polymer solution exceeding a predetermined amount in the rotating container flows out of the rotating container. The amount of polymer solution in the rotating container can always be kept constant by supplying a sufficient amount of polymer solution, and the centrifugal force acting on the polymer solution in the rotating container can always be kept constant. Uniform nanofibers can be produced, and the polymer solution that has flowed out can be collected and reused, so that the polymer solution is not wasted, and therefore the apparatus cost and material cost are not reduced. Et al, can be produced with good productivity uniform nanofibers.

  In addition, another nanofiber manufacturing apparatus of the present invention includes a conductive rotating container that is rotatably supported and has a plurality of small holes at radial distances from the rotating shaft core, and a solvent in the rotating container. Polymer solution supply means for supplying a polymer solution in which a polymer substance is dissolved, and when the amount of the polymer solution in the rotating container exceeds a predetermined amount, the polymer solution exceeding the predetermined amount is Means for discharging, recovery means for recovering and supplying the polymer solution flowing out to the polymer solution supply means, rotation driving means for rotating the rotating container, and a collector disposed at a predetermined distance from the rotating container; , Comprising a first high voltage generating means for applying a high voltage between the rotating container and the collector, and a controller for controlling the rotation driving means, the first voltage generating means and the polymer solution supply means. Formed between the rotating container and the collector Nanofibers are generated by the generated electric field and flow toward the collector, and in the same way as described above, uniform nanofibers can be produced with good productivity while reducing the equipment cost and material cost. The nanofibers collected can be collected on the collection body.

  In addition, when the rotating container is constituted by a cylindrical container having a plurality of small holes on the peripheral surface and an annular weir for allowing a polymer solution exceeding a predetermined amount to flow out is provided on one side surface of the cylindrical container, the cylindrical container A large amount of nanofibers can be produced uniformly from the entire circumference of the container at a time, ensuring high productivity, and flowing a polymer solution exceeding a predetermined amount through an annular weir on one side of a cylindrical container. By doing so, the above-described effects can be achieved with a very simple configuration.

  A reflection electrode disposed on one side in the axial direction of the rotating container; and second high voltage generating means for applying a high voltage having the same polarity as the charged charge of the rotating container to the reflecting electrode. When a high voltage is applied to the reflective electrode, the nanofibers in the generation process are deflected in the axial direction of the rotating container by the reflective electrode so that the nanofibers generated by the centrifugal force are spread as they are. The fiber can be easily collected within a required range, and the reflective electrode is disposed on one side not facing the outflow direction of the charged polymer solution. There is no fear that the outflow will be hindered, and nanofibers can be produced stably and efficiently. Even if droplets that have not been made into fibers are generated, they will be scattered to the surroundings by centrifugal force. To flow to injured deflected, it can be collected only good nanofibers quality.

  In addition, when a blower fan is disposed on one side in the axial direction of the rotating container, the flow direction of the nanofibers during the production process can be effectively deflected by blowing air from one side in the axial direction of the rotating container. The evaporated solvent is quickly discharged, the concentration of the solvent in the surrounding atmosphere is not increased, and the solvent is smoothly evaporated, and the electrostatic explosive action is reliably obtained and the desired nanofiber is reliably manufactured. can do.

  According to the method and apparatus for producing nanofibers of the present invention, a large amount of nanofibers made of a polymer material having a submicron diameter from a linear polymer solution flowing out from a plurality of small holes can be produced in a simple and compact configuration. It can be efficiently manufactured, and the polymer solution that has flowed out of the small hole is first stretched by centrifugal force, so it is not necessary to make the small hole extremely small, and it is formed long in order to concentrate the charge as described above. Since there is no need, it is only necessary to provide small holes in the rotating container, and it can be manufactured easily and inexpensively, and maintenance can be easily performed even if a large number of small holes are provided. Since the polymer solution flows out of the rotating container, the amount of the polymer solution in the rotating container can be kept constant by simply supplying a sufficient amount of the polymer solution. The centrifugal force acting on the polymer solution pushed out from the can be made constant, so that uniform nanofibers can be produced at all times, and the polymer solution that has flowed out is recovered and supplied again into the rotating container. Since the polymer solution is reused, the polymer solution is not wasted. Therefore, uniform nanofibers can be manufactured with high productivity while reducing the apparatus cost and the material cost.

  Hereinafter, each embodiment of the manufacturing method and apparatus of the nanofiber and polymer web of this invention is described, referring FIGS.

(First embodiment)
First, a first embodiment of the nanofiber manufacturing apparatus of the present invention will be described with reference to FIGS.

  1 and 2, reference numeral 1 denotes a cylindrical container having a diameter of 30 to 400 mm as a rotating container, and the end portion of the cylindrical body 2 is penetrated through the end portion of the cylindrical body 2 in the same axial state and fixed integrally. The cylinder 2 is supported so as to be rotatable around the axis as indicated by an arrow R. The cylinder 2 is made of a material having high electrical insulation. The other end of the cylindrical container 1 is closed, and a plurality of small holes 3 having a diameter of about 0.1 to 2 mm are formed on the circumferential surface at intervals of several mm. The small hole 3 may be formed by simply making a hole in the peripheral wall of the cylindrical container 1, or may be configured by mounting a short nozzle on the peripheral wall.

  The cylinder 2 is rotatably supported via a bearing 5 by a support frame 4 made of a material having high electrical insulation, and is provided on an output shaft of a pulley 6 and a motor 9 provided on the outer periphery thereof. It is rotationally driven at a rotational speed of 30 to 3000 rpm by a motor 9 as rotational drive means via a belt 8 wound between the pulley 7. As the motor 9, a sensorless DC motor is preferably applied because the sensor may malfunction due to the influence of high-voltage noise.

  A solution supply tube 10 as a polymer solution supply means is inserted into the cylindrical container 1 through the center of the cylindrical body 2, and an L-shaped bent portion 10a is formed downward at the tip thereof. A polymer solution 11 obtained by dissolving a polymer substance, which is a nanofiber material, in a solvent is supplied into the cylindrical container 1 through the solution supply pipe 10. By rotating the cylindrical container 1 while supplying the polymer solution 11 into the cylindrical container 1, the excessively supplied polymer solution 11 is exposed to the outside through the cylinder 2 using the inner periphery of the cylinder 2 as a weir. The polymer solution 11 having a uniform thickness is formed on the entire inner circumference of the cylindrical container 1. That is, assuming that the inner diameter of the cylindrical container 1 is D1 and the inner diameter of the cylindrical body 2 is D2, the layer of the polymer solution 11 having a substantially constant thickness T = (D1−D2) / 2 is the inner circumference of the cylindrical container 1. Formed.

  A recovery container 12 as a recovery means is disposed on the support frame 4 so as to recover the polymer solution 11 that has flowed outside through the cylindrical body 2. As indicated by phantom lines in FIG. 1, receiving means 13 for receiving the polymer solution 11 flowing out from the cylinder 2 and guiding it to the collection container 12 without being scattered around is provided. Further, the recovery container 12 is configured to supply the polymer solution 11 in an amount corresponding to the consumed polymer solution 11 by a solution supply means (not shown). The polymer solution 11 in the collection container 12 is sucked by a supply pump 15 as a polymer solution supply means through a suction pipe 14 and is fed at a predetermined flow rate into the cylindrical container 1 through the solution supply pipe 10. .

  Examples of the polymer substance constituting the polymer solution 11 include polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, polyfluoride. Vinylidene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, nylon, aramid, poly Examples include caprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, and polypeptide Can, at least one selected from these are used, but the invention is not particularly limited thereto.

  Solvents that can be used are 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, benzoate Propyl acid, methyl acetate, ethyl acetate, propyl acetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, methyl chloride, ethyl chloride, methylene chloride, chloroform, o-chloro Toluene, p-chlorotoluene, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane, dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethyl bromide, propyl bromide, acetic acid, benzene, Examples include toluene, hexane, cyclohexane, cyclohexanone, cyclopentane, o-xylene, p-xylene, m-xylene, acetonitrile, tetrahydrofuran, N, N-dimethylformamide, pyridine, water and the like, and at least one selected from these is used. However, the present invention is not limited to these.

  In addition, an inorganic solid material can be mixed in the polymer solution. Examples of the inorganic solid material include oxides, carbides, nitrides, borides, silicides, fluorides, sulfides, and the like. However, it is preferable to use an oxide from the viewpoints of heat resistance and workability. The oxides include Al2O3, SiO2, TiO2, Li2O, Na2O, MgO, CaO, SrO, BaO, B2O3, P2O5, SnO2, ZrO2, K2O, Cs2O, ZnO, Sb2O3, As2O3, CeO2, V2O3, Cr2O3, Cr2O3, Cr2O3 , CoO, NiO, Y 2 O 3, Lu 2 O 3, Yb 2 O 3, HfO 2, Nb 2 O 5 and the like can be exemplified, and at least one selected from these can be used, but is not particularly limited thereto.

  A high voltage of 1 kV to 100 kV, preferably 10 kV to 100 kV, generated by the first high voltage generating means 16 is applied to the cylindrical container 1 via the bearing 5 and the conductive member 17. As a result, a high voltage is also applied to the polymer solution 11 accommodated therein. When the cylindrical container 1 is driven to rotate at a high speed by the motor 9, a centrifugal force acts on the polymer solution 11 to flow out linearly from each small hole 3, and is further stretched by the action of the centrifugal force to be a thin polymer. A linear body is generated. The polymer linear body to which this high voltage is applied is charged by the action of an electric field formed around the cylindrical container 1, and the solvent of the polymer solution 11 evaporates. This reduces the diameter of the polymer linear body. Along with this, the charged charge is concentrated, and when the Coulomb force exceeds the surface tension of the polymer solution, a primary electrostatic explosion occurs and the film is stretched explosively. An electrostatic explosion occurs and the fiber is stretched explosively, and in some cases, a third electrostatic explosion occurs and the film is stretched to efficiently produce nanofibers f made of a polymer material having a submicron diameter. .

  A reflective electrode 18 is disposed on the support frame 4 so as to face one side of the cylindrical container 1 with an appropriate interval, and a high voltage generated by the second high voltage generating means 19 is applied to the reflective electrode 18. Applied. The second high voltage generating means 19 has the same polarity as the first high voltage generating means 16 and is configured to generate substantially the same high voltage and apply it to the reflective electrode 18, as shown in FIG. As indicated by the arrow D, the polymer linear body produced by flowing out and stretching from the cylindrical container 1 by the reflective electrode 18 and the nanofiber f produced by electrostatic explosion are indicated by the arrow D. It is comprised so that it may flow toward the other side.

  A conductive collector 20 is disposed on the other side of the cylindrical container 1 so as to face each other at an appropriate distance, and is applied to the cylindrical container 1 generated by the third high voltage generating means 21. A high voltage having a polarity opposite to that of the voltage is applied. Note that it is only necessary to apply a large potential difference between the cylindrical container 1 or the reflective electrode 18 and the collector 20 to generate an electric field between them, so that the collector 20 may be simply grounded. The nanofiber f is generated as described above by the electric field formed by the large potential difference between the cylindrical container 1 or the reflective electrode 18 and the collector 20, and as shown in FIG. Is moved toward the collector 20 and deposited thereon. By applying a high voltage with a polarity opposite to that of the cylindrical container 1 to the collector 20, the generated nanofibers f are collected even if a distance of about 2 m is separated between the cylindrical container 1 and the collector 20, for example. 20 can be deposited. As the first to third high voltage generating means 16, 19, and 21, it is preferable that the switches SW1, SW2, and SW3 can be arbitrarily switched on and off as necessary.

  Next, the control configuration will be described with reference to FIG. In FIG. 3, the motor 9, the supply pump 15, and the first to third high voltage generation means 16, 19, and 21 are controlled by the control unit 22. In response to a work command from the operation unit 23, the control unit 22 performs operation control based on the operation program stored in the storage unit 24 and various data input and stored from the operation unit 23, and the operation state and various Data is displayed on the display unit 25.

  In the above configuration, a predetermined amount of the polymer solution 11 is supplied into the cylindrical container 1 by the supply pump 15, and a predetermined high voltage is applied to the cylindrical container 1 from the first high voltage generating means 14. Thus, the polymer solution 11 accommodated in the cylindrical container 1 is charged to a high voltage. By rotating the cylindrical container 1 at high speed with the motor 9 in this state, the polymer solution 11 flows out linearly from the plurality of small holes 3 as described above, and a polymer linear body is formed. The polymer linear body that is greatly stretched by the action of centrifugal force and charged at a high voltage becomes charged by the action of an electric field, and then stretches to reduce the diameter and evaporate the solvent. Concentrated, causing a primary electrostatic explosion to be stretched explosively, and then further evaporating the solvent, resulting in a secondary electrostatic explosion and further explosively stretching, and in some cases, a third electrostatic explosion The nanofiber f which consists of a polymeric substance which has a submicron diameter from the polymer solution linear body which flowed out and extended | stretched from the some small hole 3 is manufactured.

  Here, a layer of the polymer solution 11 having a substantially constant thickness T is formed on the inner periphery of the cylindrical container 1, and the excess polymer solution 11 beyond the cylinder body 2 functions as a weir. And is collected in the collection container 12 and reused. Thus, since the amount of the polymer solution 11 in the cylindrical container 1 is always controlled to be substantially constant, a constant centrifugal force acts on the polymer solution 11 in the cylindrical container 1, and a small hole in the cylindrical container 1 is obtained. The centrifugal force acting on the polymer solution 11 extruded from 3 is constant, and the polymer solution 11 can flow out uniformly in a linear shape, and as a result, a uniform nanofiber f can be manufactured.

  Furthermore, after the polymer solution linear body is stretched by the action of centrifugal force when the nanofibers f are generated, the reflective electrode 18 is used to expand the other end in the axial direction of the cylindrical container 1. Since the liquid is deflected laterally and flows, the produced nanofibers f can be easily collected within a required range of the collector 20.

  In addition, since the reflective electrode 18 is disposed on one side of the cylindrical container 1, the reflective electrode 18 is disposed as in the case where a parabolic reflective electrode is disposed facing the outer peripheral surface of the cylindrical container 1. Is not opposed to the outflow direction of the charged polymer solution 11, and there is no fear that the outflow of the polymer solution 11 is hindered by the charge of the reflective electrode 18, so that the nanofiber f can be manufactured stably and efficiently. In addition, even if droplets that have not been made into fibers are generated, they are scattered as they are by centrifugal force, and only appropriate nanofibers f are deflected and flow toward collector 20, so that only high-quality nanofibers f are produced. Can be collected. The nanofibers f thus charged are deposited on the collector 18 to produce a highly porous polymer web with high productivity.

  Moreover, since the polymer solution linear body formed by flowing out from the small hole 3 of the cylindrical container 1 is greatly stretched by centrifugal force, the diameter of the small hole 3 can be about 0.1 to 2 mm, Since it is not necessary to make it extremely small and it is not necessary to concentrate electric charges unlike the case where an electrostatic explosion is first generated, the small hole 3 does not need to be formed in an elongated nozzle and is not affected by electric field interference. Even if they are arranged at a high density, they can be reliably and effectively stretched, so that a large amount of nanofibers f can be efficiently produced with a simple and compact configuration. In addition, a large amount of nanofibers can be manufactured uniformly from the entire circumference of the cylindrical container 1 at a time, and high productivity can be ensured, and the shape and configuration are simple, so the equipment cost is reduced. Can be planned. Further, since the small holes 3 do not need to be formed long, it is only necessary to simply provide the small holes 3 on the outer peripheral wall of the cylindrical container 1, and they can be manufactured easily and inexpensively, and maintenance is possible even if a large number of small holes 3 are provided. Simple.

  The motor 9 is configured to control the rotational speed of the cylindrical container 1 based on the viscosity of the polymer solution 11 accommodated in the cylindrical container 1, thereby the viscosity of the polymer solution 11. Accordingly, the necessary centrifugal force can be applied to the polymer solution 11 to manufacture the nanofiber f reliably and efficiently.

  In the above illustrated example, the reflective electrode 18 is fixedly disposed on the support frame 4 insulated from the cylindrical container 1, and the high voltage generated by the second high voltage generating means 19 is applied. Although the reflective electrode 18 is fixed to the outer periphery of the cylindrical body 2 and electrically connected to the cylindrical container 1, the same height as that of the cylindrical container 1 generated by the first high voltage generating means 16 is shown. A voltage may be applied together. In this case, the reflective electrode 18 also rotates together with the cylindrical container 1 but has no functional effect.

  In addition, a blowing unit that blows air toward the other side of the cylindrical container 1 may be disposed between the reflective electrode 18 and the cylindrical container 1. Then, the solvent evaporated by the air blowing is quickly discharged, and the solvent concentration in the surrounding atmosphere does not increase. Therefore, the solvent is smoothly evaporated and the electrostatic explosion action is reliably obtained, and the desired nanofiber f is obtained. Generated reliably. Moreover, the effect | action which deflects the flow direction of the nanofiber f in a production | generation process more effectively is also acquired.

  In the above configuration example, the cylindrical body 2 is configured to be rotatable and the cylindrical container 1 is fixed to the cylindrical body 2. However, the cylindrical body 2 is fixed to the support frame 4 and provided. The cylindrical body 1 may be rotatably supported by the cylindrical body 2, and in that case, the receiving means 13 need not be provided.

(Second Embodiment)
Next, a second embodiment of the nanofiber manufacturing apparatus of the present invention will be described with reference to FIGS. In the following description of the embodiment, the same components as those in the preceding embodiment are denoted by the same reference numerals, description thereof will be omitted, and only differences will be mainly described.

  In the first embodiment, the polymer solution 11 is sucked from the collection container 12 installed on the support frame 4 through the suction pipe 14 by the supply pump 15 and supplied into the cylindrical container 1. In this embodiment, as shown in FIGS. 4 and 5, a large-capacity storage container 26 is provided separately from the recovery container 12, and the polymer recovered in the recovery container 12 is shown in this embodiment. The solution 11 is delivered to the storage container 26 through the delivery pipe 27, and the tip of the suction pipe 14 connected to the suction port of the supply pump 15 is inserted into the storage container 26.

  Also in this embodiment, the same effect as that of the first embodiment can be obtained, and an excessive amount of the polymer solution 11 that has flowed out of the cylindrical container 1 can be increased in volume through the collection container 12 on the support frame 4. Therefore, the polymer solution 11 can be stably fed from the storage container 26 into the cylindrical container 1.

(Third embodiment)
Next, a third embodiment of the nanofiber manufacturing apparatus of the present invention will be described with reference to FIG.

  In the present embodiment, the cylindrical container 1 has an annular ridge 31 that functions as a weir at one end thereof, the inside thereof opens, and the other end that penetrates the axial center position from the one end opening toward the other end. A rotating shaft 32 is integrally coupled to the closing wall. The rotary shaft 32 is rotatably supported by a bearing portion 34 provided on a support cylinder 33 provided on the support frame 4, and the tip of the rotary shaft 32 is disposed on the rotary support cylinder 33 via a shaft coupling 32 a. The motor 9 is connected to the motor 9 so that the motor 9 can be driven to rotate. The receiving means 13 is attached to the outer periphery of the end portion of the support cylindrical body 33 so as to surround the outer periphery of the one end portion of the cylindrical container 1, and the receiving means 13 returns the polymer solution 11 recovered inside to the recovery container 12. It has a pipeline 13a.

  The polymer solution 11 in the collection container 12 is configured to be supplied into the cylindrical container 1 through the solution supply pipe 10 by a supply pump 15 such as a gear pump. Further, a liquid level sensor 35 for detecting the liquid level of the polymer solution 11 in the recovery container 12 is provided, and when the detected liquid level decreases to a certain level, a gear pump or the like is directed from the storage container 26 toward the recovery container 12. The replenishment pump 36 feeds the polymer solution 11 through the feed pipe 37 and maintains the liquid level of the polymer solution 11 in the collection container 12 within a substantially constant range.

  Further, a blower fan 38 is disposed on the side of the support cylinder 33 opposite to the cylindrical container 1, and the nanofiber f generated by flowing out and extending from the cylindrical container 1 is reflected by the reflective electrode 18. Instead of flowing toward the other side of the cylindrical container 1 by the formed electric field, the gas flow W indicated by the arrow formed by the blower fan 38 is caused to flow toward the other side of the cylindrical container 1. It is configured. In addition, the metal mesh-like reflective electrode 18 is disposed on the outer periphery of the support cylinder 33 so that the nanofibers f flow toward the other side of the cylindrical container 1 by both the electric field and the gas flow W by the reflective electrode 18. Anyway.

  Also in this embodiment, the same operational effects as those of the first embodiment can be obtained, and the rotation mechanism of the cylindrical container 1 can be configured in a compact manner, and the excess polymer solution 11 in the cylindrical container 1 can be reduced. Since it flows out smoothly and smoothly directly from the annular trough 31 at one end of the cylindrical container 1, the layer thickness of the polymer solution 11 in the cylindrical container 1 can be kept constant with good responsiveness. The nanofibers f generated from the cylindrical container 1 in the flow W can smoothly flow toward the other side of the cylindrical container 1.

  In the above description of the embodiment, an example in which either one or both of the reflective electrode 18 and the blower fan 38 is provided is shown. However, a high voltage having a polarity opposite to the applied voltage to the cylindrical container 1 is applied. Alternatively, the nanofiber f generated from the cylindrical container 1 can be caused to flow toward the collector 20 and be deposited on the collector 20 even when the grounded collector 20 is provided.

  Further, in the description of each of the above embodiments, a high voltage is applied to the cylindrical container 1 from the first high voltage generating means 16, and the collector 20 is grounded or reversed in polarity by the third high voltage generating means 21. Although an example in which a voltage is applied is shown, a configuration may be adopted in which a positive or negative high voltage is applied to the collector 20 by the third high voltage generator 21 and the cylindrical container 1 side is grounded.

  According to the method and apparatus for producing nanofibers of the present invention, a polymer solution exceeding a predetermined amount in a rotating container is allowed to flow out of the rotating container. Since the amount of the polymer solution in the rotating container can be made constant at all times, the centrifugal force acting on the polymer solution pushed out from the small hole of the cylindrical container can be made constant, so that uniform nanofibers can always be produced. It can be suitably used for producing high-quality nanofibers with high productivity, which are preferably applied to filters, battery separators, polymer electrolyte membranes and electrodes of fuel cells, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal front view of a nanofiber manufacturing apparatus according to a first embodiment of the present invention. The perspective view which shows the manufacture state of the polymer web in the same embodiment. The block diagram which shows the control structure of the embodiment. The longitudinal cross-sectional front view of the manufacturing apparatus of the nanofiber of the 2nd Embodiment of this invention. The perspective view which shows the manufacture state of the polymer web in the same embodiment. The longitudinal cross-sectional front view of the manufacturing apparatus of the nanofiber of the 3rd Embodiment of this invention. The schematic block diagram of the manufacturing apparatus of the polymer web of a prior art example. The principal part structure of the other structural example of the prior art example is shown, (a) is a front view, (b) is a partially enlarged bottom view. Explanatory drawing of the problem in the conventional example. Explanatory drawing of the further problem in the conventional example. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal front view of a nanofiber production apparatus preceding the present invention.

Explanation of symbols

1 Cylindrical container (rotary container)
2 cylinder (weir)
3 Small hole 9 Motor (Rotation drive means)
10 Solution supply pipe (polymer solution supply means)
11 Polymer solution 12 Collection container (collection means)
15 Supply pump (polymer solution supply means)
16 First high voltage generating means 18 Reflecting electrode 19 Second high voltage generating means 20 Collector (collector)
22 Control Unit 31 Weir 38 Blower Fan f Nanofiber

Claims (10)

  A polymer solution in which a polymer substance is dissolved in a solvent is supplied into a conductive rotating container having a plurality of small holes, the rotating container is rotated, an electric field is applied to the polymer solution flowing out of the small holes, and centrifugal force is generated. In a nanofiber manufacturing method in which a nanofiber made of a polymer material is drawn by electrostatic explosion accompanying evaporation of the solvent, and the amount of the polymer solution in the rotating container exceeds a predetermined amount, A method for producing nanofibers, wherein a polymer solution exceeding a fixed amount is allowed to flow out of a rotating container, and the discharged polymer solution is collected and supplied again into the rotating container.   The nano container according to claim 1, wherein the rotating container is composed of a cylindrical container having a plurality of small holes on the peripheral surface, and a polymer solution exceeding a predetermined amount is allowed to flow out through an annular weir provided on one side surface of the rotating container. Fiber manufacturing method.   2. The collector is arranged at a predetermined distance from the rotating container, a high voltage is applied between the rotating container and the collecting body, and the generated nanofibers are caused to flow toward the collecting body. Or the manufacturing method of the nanofiber of 2.   Apply a voltage of the same polarity as the charged charge of the rotating container to the reflecting electrode arranged on one side of the rotating container in the axial direction so that the nanofiber in the production process is directed to the other side in the axial direction of the rotating container. The method for producing a nanofiber according to any one of claims 1 to 3, wherein the nanofiber is deflected and fluidized.   The air is blown from one side in the axial direction of the rotating container, and the nanofibers in the generation process are deflected toward the other side in the axial direction of the rotating container and flowed. The manufacturing method of nanofiber of description.   A conductive rotating container supported in a rotatable manner and having a plurality of small holes at a radial distance from the rotation axis, and a polymer for supplying a polymer solution in which a polymer substance is dissolved in a solvent in the rotating container When the amount of the polymer solution in the rotating container exceeds a predetermined amount, a means for discharging the polymer solution exceeding the predetermined amount from the rotating container, and collecting the flowing polymer solution Recovery means for supplying the polymer solution supply means, rotational drive means for rotationally driving the rotary container, first high voltage generating means for applying a high voltage to the rotary container, rotational drive means and first voltage generating means And a control unit for controlling the polymer solution supply means.   A conductive rotating container supported in a rotatable manner and having a plurality of small holes at a radial distance from the rotation axis, and a polymer for supplying a polymer solution in which a polymer substance is dissolved in a solvent in the rotating container When the amount of the polymer solution in the rotating container exceeds a predetermined amount, a means for discharging the polymer solution exceeding the predetermined amount from the rotating container, and collecting the flowing polymer solution A high voltage is applied between the collection means for supplying the polymer solution supply means, the rotation drive means for rotationally driving the rotary container, the collector disposed at a predetermined distance from the rotary container, and the rotary container and the collector. An apparatus for producing nanofibers, comprising: a first high voltage generating means, a rotation driving means, a first voltage generating means, and a controller for controlling the polymer solution supply means.   The rotary container is constituted by a cylindrical container having a plurality of small holes on its peripheral surface, and an annular weir is provided on one side surface of the cylindrical container for allowing a polymer solution exceeding a predetermined amount to flow out. Item 8. The nanofiber production apparatus according to Item 6 or 7.   A reflective electrode disposed on one side in the axial direction of the rotating container; and second high voltage generating means for applying a high voltage having the same polarity as the charged charge of the rotating container to the reflecting electrode. A high voltage is applied to the nanofiber manufacturing apparatus according to any one of claims 6 to 8.   The apparatus for producing nanofiber according to any one of claims 6 to 9, wherein a blower fan is disposed on one side of the rotating container in the axial direction.

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