JP2010163715A - Apparatus and method for producing nanofiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for producing a nanofiber by which a still larger amount of a high-quality nanofiber can be produced, and to provide a method for producing the nanofiber. <P>SOLUTION: The apparatus for producing the nanofiber is constituted as follows. An electrode 3 for electrification is arranged so as to face a container 2. A raw material F is discharged into air by being electrified by the electric charge induced in the container 2 by the electrode 3 for the electrification. A fibrous material F1 is formed out of the discharged raw material F by electrostatic drawing phenomena. The fibrous material F1 is further transported while being deflected by electric field transportation means including a pair of electrodes, after being transported while being deflected by air flow transportation means 7, and accumulated on a collecting body 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a nanofiber manufacturing apparatus and manufacturing method, and more particularly to a technique for manufacturing nanofibers by electrospinning.

  In recent years, the electrospinning method (charge-induced spinning method) has attracted attention because nanofibers, which are fibrous materials having submicron diameters, can be easily produced. In the electrospinning method, a liquid raw material in which a polymer material is dispersed or dissolved in a liquid is released into the air, and at the time of release, the raw material is charged at a high voltage, and the raw material is electrically stretched in the air to be nano-sized. This is a method for obtaining a fiber (see, for example, Patent Document 1).

  More specifically, the raw material charged by an electric field and released into the air evaporates the dispersion medium or solvent while flying in the air, and the volume decreases. On the other hand, since the charge imparted to the raw material is maintained regardless of the evaporation of the dispersion medium or solvent, the charge density of the raw material increases with the evaporation of the dispersion medium or solvent. Then, when the Coulomb force in the repulsion direction inside the raw material becomes larger than the surface tension of the raw material, a phenomenon occurs in which the raw material is explosively stretched linearly (hereinafter referred to as an electrostatic stretching phenomenon). This electrostatic stretching phenomenon continuously occurs in the air, and the raw material is subdivided linearly geometrically, thereby producing a fine fibrous substance having a submicron scale diameter.

  There are various methods for collecting fibrous substances generated in the air. For example, in Patent Document 2, nanofibers generated from a polymer material injected from a nozzle are stacked on a collector fed in a conveyor form. And how to collect is shown. Here, a predetermined potential difference is generated between the nozzle and the collector (see FIGS. 1 and 2 of Patent Document 2) to induce charges to be imparted to the raw material to the nozzle and to the collector. , It induces a charge to attract the produced fibrous material.

Japanese Patent Laying-Open No. 2005-330624 JP 2002-201559 A JP 2008-150769 A WO 2008/062784

However, in the above-described nanofiber collecting method, it is necessary to make the distance between the raw material discharge portion such as a nozzle and the collector very short in order to reliably deposit the nanofiber on the collector.
For example, in the example of Patent Document 2, the distance between the raw material discharge portion and the collector is 8 cm or 10 cm. However, if the distance between the two is reduced in this way, the amount of nanofibers generated is gradually reduced, and there is a problem that a large amount of nanofibers cannot be manufactured continuously.

  More specifically, when a large amount of charged nanofibers are deposited on a collector disposed in close proximity to the nozzle, the nanofiber material charged to the same polarity as the charge is less likely to be discharged from the nozzle. In addition, when a large amount of charged nanofibers stay in a narrow space between the nozzle and the collector, the discharge of the raw material from the raw material discharge portion is hindered by the charge. Furthermore, the nanofiber material discharged from the material discharge part is less likely to be charged due to the charge of the nanofiber deposited on the collector and the charge of the nanofiber filled in the space between the material discharge part and the collector. The production of nanofibers in the slab is hindered.

  In addition, when the nanofiber raw material is dissolved or dispersed in an organic solvent, if the narrow space is filled with the organic solvent, there is a risk of causing an explosion, which makes it difficult to ensure safety. Problems also arise.

  For this reason, the inventors have induced a charge in a cylindrical container having a hole in the peripheral wall, supplied a raw material for the nanofiber into the container, and rotated the container to charge the nanoparticle charged from the hole in the peripheral wall. A method for producing a nanofiber by discharging a fiber raw material by centrifugal force has been proposed (see Patent Document 3). The generated nanofiber is deflected in the axial direction of the container by air blowing, and is attracted to an electrode to which a voltage of a polarity opposite to that of the nanofiber is applied, and a collector disposed in front of the electrode. And is collected as a non-woven fabric.

  According to this method, since the discharge direction of the raw material is different from the direction in which the collector is disposed, the discharge of the raw material is inhibited or the charging to the raw material is inhibited by the charge of the nanofiber deposited on the collector. Can be prevented. In addition, the space between the raw material discharge part and the container is widened, and a large amount of air is sent in, so the density of the organic solvent is reduced and the risk of explosion due to the organic solvent filling the narrow space is reduced. It becomes possible.

  However, this method has another problem that it is difficult to make the lines of electric force between the container serving as the raw material discharge portion and the collector uniform. More specifically, in this method, the peripheral surface of the container and the collector are not arranged in parallel, and various members are arranged around the container and the collector. This is because disorder occurs. As a result, the nanofibers cannot be uniformly deposited on the collector, making it difficult to obtain a nanofiber nonwoven fabric with uniform integration density.

Further, in addition to the configuration of Patent Document 3, the present inventors, in addition to the structure of Patent Document 3, arrange an annular charging electrode for inducing charges in the container to charge the raw material around the container. It has been proposed (see FIG. 18 of Patent Document 4). With this configuration, the charge induced in the container can be easily increased, so that a sufficient charge can be given to the raw material, and the rate at which nanofibers are not generated from the raw material can be reduced.
However, even in this configuration, the electric lines of force from the container to the collector are not uniform, and there remains a problem that it is difficult to obtain high-quality nanofibers made of a nonwoven fabric having a uniform thickness.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a nanofiber manufacturing apparatus and a manufacturing method capable of producing high-quality nanofibers in a larger amount.

To achieve the above object, the present invention provides a nanofiber manufacturing method in which a liquid material containing a polymer material is discharged into the air, a fibrous material is generated by an electrostatic stretching phenomenon, and the generated fibrous material is collected. A device,
A material discharge part having a hole for discharging the raw material into the air and having a space through which the raw material passes,
A charging electrode arranged to face the raw material discharge portion at a predetermined distance, and for charging the raw material discharge portion;
An airflow generating means for generating an airflow for deflecting the generated fibrous substance and transferring it in a predetermined direction;
A collector for depositing and collecting the generated fibrous material on a surface;
An electric field generating means for generating an electric field for further deflecting and transferring the fibrous material transferred by the airflow to the collector, including a pair of transfer electrodes arranged to face each other at a certain distance;
The nanofiber manufacturing apparatus includes a potential difference generating unit that generates a predetermined potential difference between the raw material discharge portion and the charging electrode.

In the manufacturing apparatus of the present invention, in a preferred embodiment, the collection body is in the form of a long band,
A feed mechanism for feeding the collection body in the longitudinal direction;
The feeding mechanism includes an unwinding device for unwinding the collection body, and a winding device for winding the collection body on which the fibrous material is deposited.

  In another preferable embodiment, the manufacturing apparatus of the present invention includes a cylindrical guide body that guides the movement of the fibrous material transferred by the airflow to the space between the pair of transfer electrodes opposed to each other.

  In another preferable embodiment of the production apparatus of the present invention, a plurality of sets of fibrous substance generating means each including the raw material discharge portion, the charging electrode, and the airflow generating means are provided, and these fibrous substance generating means The fibrous substance generated by the above is transferred to the space between the pair of transfer electrodes by the airflow.

In another preferred embodiment of the production apparatus of the present invention, the raw material discharge part is composed of a rotating container that has the hole in the peripheral wall and is rotated around a predetermined axis.
The charging electrode includes a cylindrical guide body that guides the movement of the fibrous material transferred by the airflow, which is an annular electrode disposed around the rotating container.

Further, the present invention is a nanofiber manufacturing method for generating a fibrous substance from a liquid material containing a polymer material by an electrostatic stretching phenomenon,
Releasing the raw material from the raw material discharge part into the air a,
A step of charging a raw material released into the air by generating a predetermined potential difference between the raw material discharge portion and a charging electrode arranged opposite to the raw material discharge portion; b,
A step c in which the raw material released into the air is deflected by an air flow and the generated fibrous substance is transferred in a predetermined direction;
Step d for collecting and collecting the generated fibrous substance on the surface of a collector, and a plurality of transfer electrodes arranged to face each other with a certain distance from the fibrous substance transferred by the air flow Transferring to the collector by an electric field generated between them e
A method for producing a nanofiber comprising:

  According to the present invention, the direction of the movement of the raw material discharged from the raw material discharge portion is deflected by the air flow, and further, the fiber generated by the electric field between the plurality of transfer electrodes arranged opposite to each other at a certain distance. The direction of movement of the fibrous material is deflected and the fibrous material is deposited on the collector and collected. For this reason, the fibrous substance can be transferred by an electric field having uniform lines of electric force, and deposited on the collector to be collected. Therefore, it is possible to make the deposition state of the fibrous material uniform, and it is possible to obtain a nonwoven fabric of fibrous material (nanofibers) having a uniform integration density.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1
FIG. 1 is a side view, partly in section, showing a schematic configuration of a nanofiber manufacturing apparatus according to Embodiment 1 of the present invention.

The manufacturing apparatus includes a grounded, substantially box-shaped container 2 made of a conductor such as metal. A liquid raw material F obtained by mixing a polymer material with a dispersion medium or a solvent is sent into the container 2 through a raw material supply pipe 5 at a predetermined pressure by a pump (not shown).
A large number of pores (not shown) for discharging the raw material F sent at a predetermined pressure into the air are formed in the lower wall portion of the container 2, and the pores are formed on the wall portion of the container 2. Opening is made at the tip of a large number of projections 2a provided on the outer surface of the projection.

  In addition, a plate-like charging electrode 3 is arranged at a position facing the wall portion of the container 2 to induce a charge on the wall portion and charge the raw material F released into the air by the charge. It is installed. The charging electrode 3 is connected to one terminal (for example, a negative terminal) of the high voltage power supply 4A. The other terminal (for example, positive terminal) of the high voltage power supply 4 is grounded. Details of the high-voltage power supply 4A are shown in a dashed circle P in FIG. Although details of the high voltage power supply 4A are not shown in FIGS. 2 to 10 described later, the contents are the same as those shown in FIG.

Further, on the side of the space between the wall portion of the container 2 and the charging electrode 3 (on the side opposite to the feeding direction of the collector 12 described later), the blower 7 is directed toward the space. It arrange | positions so that it may blow in a horizontal direction. Here, the direction of air blowing by the blower 7 is parallel to the direction of feeding the collector 12. In the illustrated example, the direction of air blowing is the same as the direction of feeding of the collecting body 12, but it can also be opposite to the direction of feeding of the collecting body 12. The raw material F discharged from the tip of the protrusion 2a of the container 2 is subdivided into fibers by electrostatic stretching phenomenon as the dispersion medium or solvent evaporates while flying in the air. As a result, a fibrous substance F1 is generated. Further, the raw material F released downward from the tip of the protrusion 2a of the container 2 or the fibrous substance F1 generated therefrom (hereinafter, there is no need to distinguish between them). In this case, the direction of movement is changed by the air flow generated by the blower 7 and is transferred in the horizontal direction.

A pair of electrodes (transfer electrodes) 17 and 18 are vertically arranged at positions adjacent to the container 2 and the charging electrode 3 in the direction in which the raw material F and the like are transferred by the air flow so as to face each other. ing. Here, the distance between the pair of transfer electrodes 17 and 18 is constant over the entire surface.
In addition, the lower transfer electrode (hereinafter referred to as “feed-out side electrode”) 17 is disposed such that the upper surface thereof is flush with the upper surface of the charging electrode 3.

The upper transfer electrode (hereinafter referred to as suction side electrode) 18 is connected to one polarity terminal (in the illustrated example, a negative electrode terminal) of another high-voltage power supply 4B. The other polarity terminal of another high-voltage power supply 4B is grounded. Here, the polarity of the terminal to which the suction side electrode 18 is connected is the same as the polarity of the terminal of the high voltage power supply 4A to which the charging electrode 3 is connected. That is, a voltage having a polarity opposite to that of the electric charge charged in the fibrous substance F1 is applied to the suction side electrode 18.
On the other hand, the delivery-side electrode 17 is grounded, and as a result, a charge having the same polarity as the charge charged on the fibrous substance F1 is induced in the delivery-side electrode 17.

  As a result, an electric field is generated between the delivery side electrode 17 and the suction side electrode 18 so as to transport the fibrous substance F1 upward. Since the electric field is generated between the plate-like electrodes arranged so as to face each other at a constant distance, the electric field lines are uniform.

And the collection apparatus 10 of the fibrous substance F1 is arrange | positioned in the direction where the fibrous substance F1 is transferred by the electric field.
The collection device 10 has a long strip-shaped collection body 12 that collects and collects the fibrous substance F1 on the lower surface, and an unwinding roll 14 and a winding roll 16 as a feed mechanism that sends the collection body 12 in the longitudinal direction. And.
The collecting body 12 is arranged so as to be slidably contacted with the suction side electrode 18 or at a predetermined distance so that the lower position of the collecting body 12 is fed by the feeding mechanism. In the illustrated example, the collecting body 12 is arranged so as to be sent at a position higher than the container 2. In this way, the fibrous substance F1 can be uniformly deposited on the lower surface of the collector 12 without paying special attention to the positional relationship between the unwinding roll 14 and the container 2. However, it is also possible to arrange the unwinding roll 14 adjacent to the container 2 so that the collecting body 12 is sent at the same height as the lower surface of the container 2 or at a lower position. .

Here, it is preferable that the collector 12 is made of a thin and flexible material so that the accumulated fibrous substance F1 can be easily separated. As an example of a preferable material, a sheet formed from aramid fibers can be given. If this is coated with Teflon (registered trademark), the separability of the fibrous substance F1 (nanofiber) is further improved, which is more preferable.
The material of the collection body 12 is not limited to an insulating material. For example, a conductive material such as carbon nanofiber may be mixed to make the collection body 12 conductive.

Next, the operation of the nanofiber manufacturing apparatus having the above configuration will be described.
The raw material F supplied to the inside of the container 2 at a predetermined pressure by a pump (not shown) through the raw material supply pipe 5 is released into the air from the tip of the protrusion 2a through the pores. In addition, an electric field is generated between the charging electrode 3 to which a predetermined voltage is applied by the high voltage power source 4A and the grounded container 2, and charges of opposite polarity are respectively applied to the container 2 and the charging electrode 3. Is induced. In the illustrated example, a positive charge is induced in the container 2 and a negative charge is induced in the charging electrode 3.

  As a result, the raw material F released from the pores of the container 2 is charged by the charge (positive charge) induced in the container 2. A force directed toward the charging electrode 3 is applied to the charged raw material F by an electric field between the container 2 and the charging electrode 3.

  In this way, the raw material F flies in the air toward the charging electrode 3 by the supply pressure and electric field from the pump. While flying in the air, the dispersion medium or solvent evaporates from the raw material F, and the volume of the raw material F decreases. As the volume of the raw material F decreases, the charge density increases accordingly. When the coulomb force in the repulsion direction inside the raw material F exceeds its surface tension, an electrostatic stretching phenomenon occurs, and the raw material F is repeated by repeating this phenomenon. Is subdivided into a fibrous form to produce a fibrous substance F1 (nanofiber).

  On the other hand, the direction of movement of the raw material F or the fibrous substance F1 produced therefrom is deflected by the air flow generated by the blower 7, and is parallel to the feeding direction of the collector 12 (indicated by arrows in the figure). , Transported horizontally. The fibrous substance F1 having a positive charge, which is transferred horizontally by the air flow, is transferred upward by the electric field between the delivery side electrode 17 and the suction side electrode 18, and is below the suction side electrode 18. Is deposited on the lower surface of the collector 12 being fed.

At this time, since the delivery-side electrode 17 and the suction-side electrode 18 are plate-like electrodes arranged to face each other at a fixed distance, the electric field lines between them are uniform. ing. Therefore, the fibrous substance F1 can be deposited on the lower surface of the collecting body 12 with a uniform accumulation density.
Further, since the direction in which the fibrous substance F1 is transferred by the airflow is parallel to the feeding direction of the collecting body 12, the fibrous substance F1 can be deposited more uniformly on the surface of the collecting body 12. Become.
Furthermore, the collection body 12 can be easily arranged so as not to interfere with the container 2 by setting the feeding position of the collection body 12 to a position higher than the container 2. Therefore, without depending on the arrangement of the container 2, the feeding position of the collecting body 12 can be optimized, and a uniform high-quality nanofiber nonwoven fabric can be obtained.

In addition, since a large amount of air is supplied by the air flow generated by the blower 7, even when the raw material F contains a volatile organic solvent or organic dispersion medium, they are not filled with high density. The risk of explosion, etc. can be reduced.
Further, by increasing the temperature of the airflow generated by the blower 7 to a predetermined temperature using a heating device or the like before deflecting the raw material F, the evaporation of the volatile organic solvent or organic dispersion medium is further accelerated. be able to. Thereby, the electrostatic stretching phenomenon is promoted, and finer nanofibers can be generated.

Further, since the fibrous substance F1 is transported upward by the electric field, the fibrous substance F1 generated by sufficiently subdividing the raw material F is given below the collector 12 by being sufficiently charged. It rises until it reaches the side surface, is deposited on the lower side of the collector 12 and is collected as a non-woven fabric. On the other hand, even if the raw material F is not sufficiently charged and the solvent or the like evaporates, the electrostatic stretching phenomenon does not appear and the polymer material remaining as a lump is the surface below the collector 12 due to gravity. A lot of parts are eliminated by reaching the
In this way, it is possible to manufacture a high-quality nanofiber with a small amount of polymer material lump.

  Here, it is preferable to apply a voltage of 1 to 200 kV to the charging electrode 3. More preferably, a high voltage of 10 kV or higher is applied. In particular, the electric field strength between the container 2 and the charging electrode 3 is important, and it is preferable to adjust the applied voltage and the distance between the container 2 and the charging electrode 3 so that the electric field strength is 1 kV / cm or more. . Thereby, an even and strong electric field can be generated between the container 2 and the charging electrode 3. The same applies to the delivery-side electrode 17 and the suction-side electrode 18.

  In this embodiment, a voltage is applied to the charging electrode 3 and the container 2 is grounded. However, the present invention is not limited to this, and the charging electrode 3 is grounded and a voltage is applied to the container 2. It is good. Moreover, it is good also as what applies the voltage of reverse polarity to both the container 2 and the electrode 3 for charging. In short, a voltage is applied to one of the container 2 and the charging electrode 3 so as to generate a predetermined potential difference between the container 2 and the charging electrode 3, or between the container 2 and the charging electrode 3. A voltage may be applied.

Further, in the embodiment, a negative voltage is applied to the charging electrode 3 to generate a positively charged fibrous substance F1, and a negative voltage is applied to the suction side electrode 18 to create a fiber. However, the present invention is not limited to this, and a positive voltage is applied to the charging electrode 3 to generate a negatively charged fibrous substance F1. The fibrous material F1 may be collected by applying a voltage of. Alternatively, the collecting electrode 18 may be grounded and a voltage may be applied to the delivery side electrode 17.
In the embodiment, the container 2 is a conductor such as a metal. However, the present invention is not limited to this. Even when the container 2 is made of a material having no electrical conductivity, the raw material F is in the air. If the vicinity of the hole for discharging the electrode is made of a conductive material, an electric field is generated between the portion and the charging electrode 3 to charge the raw material discharged from the hole. it can.

In the embodiment, the blower 7 is disposed on the side of the space between the wall portion of the container 2 and the charging electrode 3 (on the side opposite to the feeding direction of the collecting body 12). However, the present invention is not limited to this method, and it may be configured to generate an air flow by arranging a suction means for sucking air in a direction to deflect the raw material released from the hole of the container 2. Good.
In the embodiment, the feeding direction of the collecting body 12 is determined by the arrangement of the unwinding roll 14 and the winding roll 16, but the arrangement of the unwinding roll 14 and the winding roll 16 is exchanged to collect the collecting body 12. Even if the feed direction is reversed, the same effect can be obtained.

  Polymer materials to be included in the raw material F are polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, and polyvinylidene fluoride. , Vinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, vinylidene chloride-acrylate copolymer, polyacrylonitrile, acrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, nylon, aramid, polycaprolactone, poly Suitable examples include lactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, and polypeptide. At least one is used selected from these. However, the polymer materials that can be included in the raw material F are not limited to these, and even existing substances that have been newly recognized as being suitable as raw materials for nanofibers, or will be developed in the future Any substance that is suitable for use as a raw material for nanofibers can be suitably used.

  The dispersion medium or solvent for dispersing or dissolving the polymer material is 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, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane, dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethyl bromide , Propyl bromide, acetic acid, benzene, toluene, hexane, cyclohexane, cyclohexanone, cyclopentane, o-xylene, p-xylene, m-xylene, acetonitrile, tetrahydrofuran, N, N-dimethylformamide, pyridine, water and the like are suitable. It can illustrate as a thing and at least 1 sort (s) chosen from these is used. However, the dispersion medium or solvent for dispersing or dissolving the polymer material is not limited to these, and even if it is an existing substance, the suitability of the polymer material as a dispersion medium or solvent in the electrospinning method is new. Or materials that will be developed in the future and that are suitable for use as a dispersion medium or solvent can be suitably used.

The raw material F can also be mixed with an inorganic solid material. Examples of the inorganic solid material that can be mixed include oxides, carbides, nitrides, borides, silicides, fluorides, and sulfides. From the viewpoint of heat resistance, workability, etc., it is preferable to use an oxide. 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 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. However, the inorganic solid material mixed in the raw material F is not limited to these.

  Although the mixing ratio of the polymer material and the dispersion medium or solvent depends on the type of the polymer material, it is preferable that the mixing ratio is 60 to 98% by mass.

<< Embodiment 2 >>
Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is a modification of the first embodiment. Only the parts different from the first embodiment will be mainly described below.
In the second embodiment, the angle at which the nanofiber generating unit including the container 2, the charging electrode 3, and the blower 7 is installed is changed from the first embodiment. More specifically, the transfer direction of the fibrous substance F1 by the airflow is changed obliquely upward by a predetermined angle θ.
Thus, the transfer direction of the fibrous substance F1 by the airflow is not limited to the direction perpendicular to the transfer direction by the electric field, and may be set to a direction that intersects obliquely with the transfer direction by the electric field.

<< Embodiment 3 >>
Next, Embodiment 3 of the present invention will be described with reference to FIG. The third embodiment is a modification of the first embodiment. Only the parts different from the first embodiment will be mainly described below.
In the third embodiment, the delivery-side electrode 17 is not grounded, and a voltage having a polarity opposite to that of the suction-side electrode 18 is applied. More specifically, the delivery-side electrode 17 is connected to one terminal (a positive terminal in the illustrated example) of another high-voltage power supply 4C. The other terminal of the high voltage power supply 4C is grounded.

  In this way, by applying voltages of opposite polarities to the delivery side electrode 17 and the suction side electrode 18 by the separate high voltage power sources 4B and 4C, the fibrous substance F1 is transferred between the electrodes. An electric field can be generated.

  In the third embodiment, voltages having opposite polarities are applied to the delivery-side electrode 17 and the suction-side electrode 18 by separate high-voltage power supplies 4B and 4C, respectively. Only one high voltage power source may be used to apply voltages having opposite polarities to the delivery side electrode 17 and the suction side electrode 18. That is, an electric field having a predetermined direction may be formed between the delivery side electrode 17 and the suction side electrode 18.

<< Embodiment 4 >>
Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is a modification of the first embodiment. Only the parts different from the first embodiment will be mainly described below.
In Embodiment 4, the collection apparatus 10 is arrange | positioned under the transfer path | route of the fibrous substance F1 transferred with the airflow which the air blower 7 generate | occur | produces. Correspondingly, the delivery side electrode 17 is disposed on the upper side, and the suction side electrode 18 is disposed on the lower side. The collection body 12 is disposed so as to be sent above the suction side electrode 18, and the fibrous substance F <b> 1 is deposited on the upper surface of the collection body 12 and collected.

  Thus, in the present invention, it is also possible to configure the fibrous substance F1 to be transported from the top to the bottom by the electric field transport means composed of a pair of transport electrodes. The effect of the present invention that the fibrous substance F1 can be transferred with a uniform electric field of electric lines of force can be obtained.

<< Embodiment 5 >>
Next, a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment is a modification of the first embodiment, and only the parts different from the first embodiment will be mainly described below.
In the fifth embodiment, the cylindrical guide body 6 for guiding the movement of the fibrous substance F1 transferred by the air flow generated by the blower 7 includes the container 2, the charging electrode 3, the delivery side electrode 17, and the suction side. It is arranged between the electrodes 18. The guide body 6 is preferably made of an insulator.
As a result, the risk of short-circuiting between the charging electrode 3 and the delivery-side electrode 17 is reduced, and the risk of explosion due to ignition of the solvent or dispersion medium of the raw material due to the short spark can be reduced. In addition, damage to the power supply due to a short circuit can be avoided. Therefore, safety is improved and durability of the device is improved.

  The material of the guide body 6 is preferably a material that is as difficult to be charged as possible. For example, it is preferably composed of wood, cotton, paper, or the like. Thereby, the charged fibrous substance F1 passing through the inside of the guide body 6 becomes difficult to adhere to the inner surface of the guide body 6, and most of the fibrous substance F1 can be deposited on the collecting body 12 and collected. .

If the fibrous substance F1 is charged with a positive charge, it is also preferable that the material of the guide body 6 is easily charged with a positive charge. For example, glass, asbestos and nylon are preferable. On the contrary, if the fibrous substance F1 is charged with a negative charge, it is also preferable that the material of the guide body 6 is easily charged with a negative charge. For example, polytetrafluoroethylene, polyvinyl chloride, polyethylene and the like are preferable.
In this way, the guide body 6 is made of a material that is easily charged to the same polarity as the charge charged on the fibrous substance F1, thereby preventing the fibrous substance F1 from adhering to the inner surface of the guide body 6. can do. Thereby, the frequency of the maintenance for removing the fibrous substance F1 etc. adhering to the guide body 6 can be reduced, and the productivity is improved.

<< Embodiment 6 >>
Next, a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment is a modification of the first embodiment, and only the parts different from the first embodiment will be mainly described below.
In the sixth embodiment, a plurality of sets (two sets in the illustrated example) each of a fibrous substance generating unit including the container 2, the charging electrode 3 and the blower 7, and the delivery side electrode 17 and the suction side electrode 18 are collected. It is provided for one collecting device 10 so as to be aligned along the direction of twelve feeds.
Here, the plurality of suction side electrodes 18 are connected to one terminal (a negative terminal in the illustrated example) of one high voltage power supply 4B.

Thus, by providing a plurality of sets of fibrous substance generation units and electric field generation units, it becomes possible to improve productivity without causing adverse effects due to electric field interference.
In the illustrated example, two suction-side electrodes 18 are provided, but it is also possible to configure them from one large plate-like electrode.

<< Embodiment 7 >>
Next, a seventh embodiment of the present invention will be described with reference to FIG. The seventh embodiment is a modification of the first embodiment. Only the parts different from the first embodiment will be mainly described below.
In the seventh embodiment, two fibrous substance generation units including the container 2, the charging electrode 3, and the blower 7 are provided to face each other. In addition, a transfer assisting unit that assists the transfer of the fibrous substance F1 by the electric field with an air flow is provided above the electric field generating unit configured by the delivery side electrode 17 and the suction side electrode 18. Correspondingly, the collecting body 12A is made of a material having higher air permeability.

Specifically, the transfer direction of the fibrous substance F1 by the air flow generated by the blower 7 in the two fibrous substance generation units is a horizontal direction parallel to the feeding direction of the collector 12. Moreover, the transfer directions are opposite to each other. The fibrous substance F1 produced | generated by these two fibrous substance production | generation parts is sent into the space between a pair of transfer electrodes, and is sent upwards by the electric field between them.
Furthermore, on the upper side of the collecting body 12 </ b> A, a transfer auxiliary unit 23 including a suction device 20 made of, for example, a blower and a cylindrical hood 21 connected to the suction port of the suction device 20 is disposed.

The hood 21 is formed so that the width in the direction parallel to the feeding direction of the collecting body 12A increases from the opening on the side connected to the suction device 20 toward the opening on the side facing the collecting body 12A. .
Moreover, it is preferable that 12 A of collection bodies are comprised from a net-like fiber so that gas may pass easily.

As described above, by supplying the fibrous substance F1 generated by the two fibrous substance generation units to one electric field generation unit, the productivity is improved while suppressing an increase in the number of parts of the manufacturing apparatus. Can be made.
Further, by providing the suction-type transfer assisting unit, when the transfer force of the fibrous substance F1 due to the electric field is small, for example, when the potential difference between the pair of transfer electrodes 17 and 18 is small, the distance between the electrodes is large. In this case, and even when the amount of loss of charge from the fibrous substance F1 is large, the fibrous substance F1 can be more reliably transferred to the collecting body 12A. Thereby, reduction of material loss can be aimed at.

In addition, as shown in FIG. 8, the direction which transfers the fibrous substance F1 by the airflow which the air blower 7 generate | occur | produces may be diagonally upward not only in a horizontal direction.
Further, as shown in FIG. 9, the direction in which the fibrous substance F1 is transferred by the air flow generated by the blower 7 is not limited to the direction parallel to the feeding direction of the collecting body 12A, but also in the direction perpendicular to the feeding direction. Good. However, in this case, it is necessary to adjust the discharge amount of the raw material F and the direction of the air current so that the accumulation density of the fibrous substance F1 is equal on the left and right in the width direction of the collector 12.

<< Embodiment 8 >>
Next, an eighth embodiment of the present invention will be described with reference to FIG. The eighth embodiment is a modification of the first embodiment. Only the parts different from the first embodiment will be mainly described below.
In the eighth embodiment, the container 2A has a substantially cylindrical outer shape with one end closed. The container 2A is configured as a rotating container that is rotationally driven by an electric motor 24 connected to a rotating shaft 2b that coincides with the cylindrical axis. The raw material F is discharged | emitted through the pore (not shown) provided in the surrounding wall with the centrifugal force by rotation of the container 2A. And container 2A is arrange | positioned so that the rotating shaft 2b may become parallel to a horizontal direction.

  Further, around the container 2A, an annular charging electrode 3A shaped like a ring formed by joining both ends in the longitudinal direction of the long plate has a certain distance from the outer peripheral surface of the container 2A. Are arranged coaxially so as to face each other. The charging electrode 3A is connected to one terminal (for example, a negative electrode terminal) of the high voltage power supply 4A. The other terminal (for example, positive terminal) of the high voltage power supply 4A is grounded. On the other hand, the container 2A is grounded, so that charges of opposite polarities are induced on the outer peripheral surface of the container 2A and the inner peripheral surface of the charging electrode 3A, and an electric field is generated between the two. For example, a positive charge is induced in the container 2A, and a negative charge is induced in the charging electrode 3A.

The blower 7 is arranged at a position further to the side than the electric motor 24 connected to the rotating shaft 2b of the container 2A. The air flow 26 generated by the blower 7 is guided between the container 2A and the charging electrode 3A by a cylindrical hood 28, and the raw material F and the like are transferred in the axial direction of the container 2A. The raw material F or the like transferred by the air flow 26 is transferred upward by the electric charge between the delivery side electrode 17 and the suction side electrode 18 and is deposited on the lower surface of the collector 12.
An annular heater 30 is disposed in the hood 28 immediately downstream of the blower 7. Thereby, the evaporation of the dispersion medium or solvent from the raw material F etc. can be accelerated | stimulated, and the fibrous substance F1 can be rapidly produced | generated from the raw material F. FIG. In addition, since the electrostatic stretching phenomenon is caused at an early stage, the fiber diameter of the generated fibrous substance F1 is further reduced, and the fine fibrous substance F1 can be stably generated.

  Thus, the force for releasing the raw material F into the air is not limited to the supply pressure of a pump or the like, and a centrifugal force obtained by rotating the container can be used. Further, the charging electrode can be an annular electrode disposed around the container. Further, the pores for releasing the raw material F do not necessarily have to be opened at the tips of the protrusions provided on the outer surface of the container, and may be opened as they are on the surface of the peripheral wall of the container.

Embodiment 9
Next, a ninth embodiment of the present invention will be described with reference to FIG. The ninth embodiment is a modification of the eighth embodiment, and only the parts different from the eighth embodiment will be mainly described below.
In the ninth embodiment, the container 2B is a rotating container having an outer shape like a abacus bead, and a plurality of holes are provided in a peripheral wall of a portion having the largest outer diameter.
Further, the container 2B is rotatably supported by a raw material liquid supply pipe 33 that also serves as a rotating shaft.
Further, around the container 2B, an annular charging electrode 3B shaped like a ring by connecting both ends of a round bar is disposed.

  The raw material liquid supply pipe 33 is rotatably supported by the support portion 32 and is connected to one end of the raw material liquid pipe 35 via a rotary joint 34. A passive gear 36 is externally mounted on the raw material liquid supply pipe 33. The passive gear 36 meshes with an active gear 38 attached to the output shaft 24a of the electric motor 24. The raw material liquid supply pipe 33 is rotated by the rotational output of the electric motor 24, and the container 2B is driven to rotate.

Further, the other end of the raw material liquid pipe 35 is connected to the raw material liquid tank 40, and a raw material liquid pump 42 and a pressure sensor 44 are disposed in the middle. The pressure sensor 44 is disposed on the downstream side of the raw material pump 42 in the raw material liquid pipe 35, detects the discharge pressure of the raw material pump 42, and outputs a signal corresponding to the detection result. An output signal of the pressure sensor 44 is input to the control unit 46.

The control unit 46 controls the material pump 42 based on the detection result of the pressure sensor 44 so that the discharge pressure of the material pump 42 becomes a predetermined pressure. Here, it is preferable to use the raw material pump 42 having a built-in pressure regulating valve so that the raw material liquid F containing the low boiling point solvent can be supplied at a constant pressure. The raw material pump 42 is preferably controlled by performing variable speed / variable torque control of an AC motor (induction motor / synchronous motor) constituting the raw material pump 42 using an inverter device.
With the above configuration, the raw material F is supplied from the raw material liquid tank 40 into the container 2B at a predetermined pressure via the raw material liquid pipe 35, the rotary joint 34, and the raw material liquid supply pipe 33.

  In this way, by connecting the raw material liquid pipe 35 and the raw material liquid supply pipe 33 via the rotary joint 34, not only the centrifugal force due to the rotation of the container 2B but also the supply pressure of the raw material F by the raw material pump 42 is obtained. It is possible to release the raw material F from the container 2B using the above. Thereby, it becomes possible to discharge | release the raw material F more smoothly, and productivity of nanofiber improves.

As mentioned above, although this invention was demonstrated by each embodiment, while describing the preferable more specific form of this invention below, the further modification of each said embodiment is demonstrated.
The outer diameters of containers 2A and 2B of Embodiments 8 and 9 are preferably 10 mm to 300 mm. This is because if the outer diameters of the containers 2A and 2B exceed 300 mm, it is difficult to concentrate the raw materials F and the like appropriately by the air flow. Further, if the outer diameter of the container 2A exceeds 300 mm, in order to stably rotate the containers 2A and 2B, it is necessary to considerably increase the rigidity of the support structure that supports the container 2A or 2B, which increases the size of the apparatus. Because. On the other hand, if the diameters of the containers 2A and 2B are smaller than 10 mm, it is necessary to increase the rotational speed in order to obtain a centrifugal force sufficient to release the raw material, in which case the load and vibration of the motor increase. This is because it is necessary to take measures against vibration. Considering the above points, the outer diameters of the containers 2A and 2B are more preferably 20 to 150 mm.

Moreover, in each said embodiment, it is good for the diameter of the pore which discharge | releases the raw material F to be 0.01-2 mm. Further, the shape of the pores is preferably circular, but may be a polygonal shape or a star shape.
The rotation speed of the containers 2A and 2B is in the range of, for example, several rpm or more and 10,000 rpm or less depending on the viscosity of the raw material F, the composition of the raw material F (type of polymer material), the type of solvent, the diameter of pores, and the like. Can be adjusted.

  Further, the inner diameters of the annular charging electrodes 3A and 3B of the eighth and ninth embodiments need to be larger than the outer diameter of the containers 2A and 2B, but are preferably 200 to 1000 mm, for example. In particular, the arrangement of the charging electrodes 3A and 3B and the applied high voltage so that the electric field strength generated by the potential difference generated between the charging electrodes 3A and 3B and the container 2A or 2B is 1 kV / cm or more. It is better to set the power supply size.

  Further, the annular charging electrodes 3A and 3B are not necessarily annular electrodes. For example, the shape seen from the axial direction may be a polygon. The charging electrodes 3A and 3B only need to be arranged so as to surround the container at a predetermined distance from the peripheral surface of the container. For example, an annular metal wire is arranged so as to surround the container. It may be configured.

  According to the present invention, since high-quality nanofibers can be manufactured with high productivity by electrospinning, it is possible to provide an inexpensive and highly reliable material as a material for a high-performance filter or the like.

It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus which concerns on Embodiment 1 of this invention. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus which concerns on Embodiment 2 of this invention. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus which concerns on Embodiment 3 of this invention. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus which concerns on Embodiment 4 of this invention. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus which concerns on Embodiment 5 of this invention. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus concerning Embodiment 6 of this invention. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus concerning Embodiment 7 of this invention. It is the side view which made the cross section a part which shows the modification of the manufacturing apparatus of FIG. FIG. 8 is a side view, partly in section, showing another modification of the manufacturing apparatus of FIG. 7. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus which concerns on Embodiment 8 of this invention. It is the side view which made the cross section a part which shows schematic structure of the nanofiber manufacturing apparatus concerning Embodiment 9 of this invention.

DESCRIPTION OF SYMBOLS 1 Nanofiber manufacturing apparatus 2 Container 3 Electrode for charging 4 High voltage power supply 6 Guide body 7 Blower 12 Collecting body 17 Sending side electrode 18 Suction side electrode F Raw material F1 Fibrous material

Claims (6)

A nanofiber manufacturing apparatus that discharges a liquid raw material containing a polymer material into the air, generates a fibrous material by an electrostatic stretching phenomenon, and collects the generated fibrous material,
A material discharge part having a hole for discharging the raw material into the air and having a space through which the raw material passes,
A charging electrode arranged to face the raw material discharge portion at a predetermined distance, and for charging the raw material discharge portion;
An airflow generating means for generating an airflow for deflecting the generated fibrous substance and transferring it in a predetermined direction;
A collector for depositing and collecting the generated fibrous material on a surface;
An electric field generating means for generating an electric field for further deflecting and transferring the fibrous material transferred by the airflow to the collector, including a pair of transfer electrodes arranged to face each other at a certain distance;
An apparatus for producing nanofibers, comprising: a potential difference generating means for generating a predetermined potential difference between the raw material discharge portion and the charging electrode. The collector is in the form of a long band,
A feed mechanism for feeding the collection body in the longitudinal direction;
The nanofiber manufacturing apparatus according to claim 1, wherein the feeding mechanism includes an unwinding device for unwinding the collection body and a winding device for winding the collection body on which the fibrous material is deposited.   3. The nanofiber manufacturing apparatus according to claim 1, further comprising a cylindrical guide body that guides the movement of the fibrous material transferred by the airflow to the pair of transfer electrodes arranged to face each other.   A plurality of sets of fibrous substance generating means composed of the raw material discharge section, the charging electrode and the airflow generating means, and the fibrous substances generated by the fibrous substance generating means are used as a pair of transfer electrodes. The nanofiber manufacturing apparatus according to any one of claims 1 to 3, wherein the nanofiber is transferred to the space between the two by the airflow. The raw material discharge part is composed of a rotating container that has the hole in the peripheral wall and is rotated about a predetermined axis.
The nanofiber manufacturing apparatus according to claim 1, wherein the charging electrode is an annular electrode disposed around the rotating container. A nanofiber manufacturing method for producing a fibrous material from a liquid material containing a polymer material by an electrostatic stretching phenomenon,
Releasing the raw material from the raw material discharge part into the air a,
A step of charging a raw material released into the air by generating a predetermined potential difference between the raw material discharge portion and a charging electrode arranged opposite to the raw material discharge portion; b,
A step c in which the raw material released into the air is deflected by an air flow and the generated fibrous substance is transferred in a predetermined direction;
Step d for collecting and collecting the generated fibrous substance on the surface of a collector, and a plurality of transfer electrodes arranged to face each other with a certain distance from the fibrous substance transferred by the air flow Transferring to the collector by an electric field generated between them e
A nanofiber manufacturing method comprising:

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