JP2010121232A - Nanofiber production apparatus, and nanofiber production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently form a gas flow for carrying nanofibers in a nanofiber production apparatus. <P>SOLUTION: The nanofiber production apparatus comprises: an outflow member 115 having outflow holes 118 for flowing out a raw material liquid 300 in a space; a charging device 111 for charging the raw material liquid 300; a gas flow-forming device 113 for forming a gas flow for carrying the nanofibers 301 produced from the raw material liquid 300 flowed out of the outflow member 115; a guide device 102 for guiding the gas flow and the nanofibers 301; a collector 103 for separate the gas flow from the nanofibers 301 to collect the nanofibers 301; a returning device 104 for returning the gas flow to the gas flow-forming device 113; and a recovery device 105 for separating and recovering a solvent evaporated from the raw material liquid 300 from the gas flow. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a nanofiber manufacturing apparatus and manufacturing method, and more particularly, to a nanofiber manufacturing apparatus and manufacturing method for transporting a nanofiber to be manufactured by a gas flow.

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

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

  A more specific description of the electrospinning method is as follows. That is, the raw material liquid charged and discharged into the space gradually evaporates the solvent while flying through the space. As a result, the volume of the raw material liquid in flight gradually decreases, but the charge imparted to the raw material liquid remains in the raw material liquid. As a result, the charge density of the raw material liquid in flight through the space gradually increases. Since the solvent continues to evaporate, the charge density of the raw material liquid further increases, and the polymer solution explodes when the repulsive Coulomb force generated in the raw material liquid exceeds the surface tension of the raw material liquid. A phenomenon of linear stretching (hereinafter referred to as electrostatic stretching phenomenon) occurs. This electrostatic stretching phenomenon occurs geometrically in the space one after another, thereby producing a nanofiber made of a polymer having a submicron diameter (see, for example, Patent Document 1).

  When the nanofibers manufactured by the electrospinning method as described above are manufactured in large quantities at one place and the nanofibers are collected in a state of being dispersed spatially, the yarn spun from the collected nanofibers is The performance becomes uniform and high production efficiency can be realized. Moreover, if nanofibers are deposited in a state of being dispersed evenly in space, it is possible to obtain a nonwoven fabric having a uniform film thickness.

Therefore, the applicant of the present application does not generate an electric field by applying a voltage between the part for flowing out the raw material liquid and the part for collecting the manufactured nanofiber, but the raw material liquid charged in a predetermined space or The nanofibers to be manufactured are transported in a gas flow and collected by a collecting device arranged away from the space, so that the nanofibers are evenly dispersed in the space and the production efficiency of the nanofiber is improved. We have already filed a nanofiber manufacturing device that can do this (unpublished).
JP 2008-31624 A

  However, when generating a large amount of nanofibers, it is necessary to evaporate a large amount of solvent from the raw material liquid, and a large amount of gas flow is required to maintain the concentration of the solvent vapor below a predetermined value. Further, when the solvent is flammable, it is necessary to control the concentration of the solvent vapor below a predetermined value. Furthermore, when a large amount of nanofibers are to be conveyed by a gas flow, a large amount of gas flow is required. In the case of generating such a large amount of gas flow, a large-sized gas flow generator is required, and the running cost is increased. In addition, if a plurality of such nanofiber manufacturing apparatuses are operated in one factory, there is a concern that the supply of gas will be insufficient. Further, since the exhausted gas stream contains the solvent evaporated from the raw material liquid, it is necessary to remove these solvent components from a large amount of the gas stream.

  The invention of the present application has been made in view of the above problems, and is a nanofiber manufacturing apparatus and nanofiber manufacturing method capable of transporting nanofibers with a large amount of gas flow and suppressing gas consumption as a whole. For the purpose of provision. It is another object of the present invention to provide a nanofiber manufacturing apparatus and a nanofiber manufacturing method that can reduce the leakage of the solvent evaporating from the raw material liquid as much as possible.

  In order to solve the above-mentioned problems, a nanofiber manufacturing apparatus according to the present invention is a nanofiber manufacturing apparatus for manufacturing a nanofiber by stretching a raw material liquid in a space, and an outflow hole through which the raw material liquid flows out into the space An outflow body, a charging device for charging the raw material liquid, a gas flow generating apparatus for generating a gas flow for transporting nanofibers manufactured from the raw material liquid flowing out from the outflow body, and guiding the nanofiber together with the gas flow Separating the gas stream and the nanofibers to collect the nanofibers, a return device for returning the gas stream to the gas stream generator, and separating the solvent evaporated from the raw material liquid from the gas stream. And a recovery device for recovery.

  As a result, the gas used for transporting the nanofiber is recovered by the recovery device after the solvent evaporating from the raw material liquid is returned to the gas flow generation device and again used for transporting the nanofiber. The generator can continue to generate a large amount of gas flow only by compensating for the pressure loss of the gas flow. Therefore, the running cost of the nanofiber manufacturing apparatus can be reduced. In addition, since the gas used for transportation is reused, there is no need to introduce a large amount of gas from the outside, and even if multiple nanofiber manufacturing devices are installed and operated in the factory, gas supply There is no shortage of quantity.

  Furthermore, it is preferable to provide an introduction device for introducing gas from the outside into a circulation circuit including the guide device and the return device.

  As a result, it is possible to compensate for the gas leaking from the circulation circuit and always keep a large amount of gas flow stably.

  In order to solve the above problems, a nanofiber manufacturing apparatus according to the present invention is a nanofiber manufacturing method for manufacturing a nanofiber by stretching a raw material liquid in a space, and an outflow step for flowing the raw material liquid into the space A charging step for charging the raw material liquid, a gas flow generating step for generating a gas flow for transporting the nanofibers manufactured from the raw material liquid flowing out from the effluent, and a guiding step for guiding the nanofiber together with the gas flow; A collecting step for separating the gas flow and the nanofibers to collect the nanofibers, a return step for returning the gas flow to the gas flow generating device, and a recovery for separating and recovering the solvent evaporated from the raw material liquid from the gas flow And a process.

  As a result, the gas used for transporting the nanofiber is recovered by the recovery device after the solvent evaporating from the raw material liquid is returned to the gas flow generation device and again used for transporting the nanofiber. The generator can continue to generate a large amount of gas flow only by compensating for the pressure loss of the gas flow. Therefore, the running cost of the nanofiber manufacturing apparatus can be reduced. In addition, since the gas used for transportation is reused, there is no need to introduce a large amount of gas from the outside, and even if multiple nanofiber manufacturing devices are installed and operated in the factory, gas supply There is no shortage of quantity.

  According to the present invention, by circulating a gas in a closed circuit, it is possible to generate a large amount of gas flow with a small amount of energy and to transport a large amount of nanofibers.

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

  FIG. 1 is a plan view showing an embodiment of a nanofiber manufacturing apparatus with a part cut away.

  As shown in the figure, the nanofiber manufacturing apparatus 100 includes a discharge device 101, a guide device 102, a collection device 103, a return device 104, a collection device 105, an introduction device 106, a separator 107, and an exhaust. Device 108.

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

  The discharge device 101 is a unit that can discharge the charged raw material liquid 300 and the manufactured nanofiber 301 on a gas flow.

  FIG. 2 is a plan view showing a part of the discharge device by cutting away.

  FIG. 3 is a perspective view showing the appearance of the discharge device.

  As shown in these drawings, the discharge device 101 includes an outflow device 110, a charging device 111, a wind tunnel body 112, a gas flow generation device 113, and a supply path 114.

  The outflow device 110 is a device that causes the raw material liquid 300 to flow out into the space. In the present embodiment, the outflow device 110 is a device that causes the raw material liquid 300 to flow out radially by centrifugal force. The outflow device 110 includes an outflow body 115, a rotating shaft body 116, and a motor 117.

  The outflow body 115 is a member for causing the raw material liquid 300 to flow out into the space, and is a member provided with a number of outflow holes 118 through which the raw material liquid 300 passes. In the case of the present embodiment, the effluent body 115 is a container that allows the raw material liquid 300 to flow out into the space by centrifugal force due to its rotation while the raw material liquid 300 is injected inward, and one end is closed. It has a cylindrical shape and is provided with a number of outflow holes 118 on the peripheral wall. The outflow body 115 is formed of a conductor in order to give a charge to the stored raw material liquid 300. The outflow body 115 is rotatably supported by a bearing 119.

  Specifically, it is preferable that the diameter of the outflow body 115 is adopted from a range of 10 mm or more and 300 mm or less. This is because if it is too large, it will be difficult to concentrate the raw material liquid 300 and the nanofiber 301 by the gas flow described later, and if the weight balance is slightly deviated, for example, the rotational axis of the effluent 115 is deviated, a large vibration will occur. This is because a structure that firmly supports the outflow body 115 is required to suppress the vibration. On the other hand, if it is too small, the rotation for causing the raw material liquid 300 to flow out by centrifugal force must be increased, which causes problems such as load and vibration of the drive source. Furthermore, it is preferable that the diameter of the outflow body 115 is adopted from a range of 20 mm or more and 100 mm or less.

  In addition, the shape of the outflow hole 118 is preferably circular, and the diameter thereof is preferably from about 0.01 mm to 3 mm, although it depends on the thickness of the outflow body 115. This is because if the outflow hole 118 is too small, it is difficult to cause the raw material liquid 300 to flow out of the outflow body 115, and if it is too large, the unit of the raw material liquid 300 that flows out from one outflow hole 118. This is because the amount per hour becomes too large (that is, the thickness of the line formed by the flowing out raw material liquid 300 becomes too thick), making it difficult to manufacture the nanofiber 301 having a desired diameter.

  In addition, the outflow body 115 is not only a member that causes the raw material liquid 300 to flow out into the space by the centrifugal force of its own rotation, but is also stationary, and the pressurized raw material liquid 300 flows out from the outflow hole 118. A member may be used. Moreover, the shape of the outflow body 115 that causes the raw material liquid 300 to flow out by centrifugal force is not limited to a cylindrical shape, and may be a polygonal cylindrical shape having a polygonal cross section or a conical shape. It is sufficient that the raw material liquid 300 can flow out of the outflow hole 118 by centrifugal force by rotating the outflow hole 118. Further, the shape of the outflow hole 118 is not limited to a circular shape, and may be a polygonal shape or a star shape.

  The rotating shaft body 116 is a shaft body for transmitting a driving force for rotating the outflow body 115 and causing the raw material liquid 300 to flow out by centrifugal force, and is inserted into the outflow body 115 from the other end of the outflow body 115. This is a rod-like body in which the closed portion and one end portion of the outflow body 115 are joined. The other end is connected to the rotating shaft of the motor 117. The rotating shaft 116 is connected to the motor 117 via the insulator 120, and the outflow body 115 and the motor 117 are electrically insulated.

  This is to protect the motor 117 when the connection of the effluent body 115 to the ground is broken due to an accident or the like. The rotating shaft body 116 is rotatably supported by a bearing 119.

  The motor 117 is a device that applies a rotational driving force to the outflow body 115 via the rotating shaft body 116 in order to cause the raw material liquid 300 to flow out from the outflow hole 118 by centrifugal force. The number of revolutions of the outflow body 115 is selected from a range of several rpm or more and 10,000 rpm or less depending on the diameter of the outflow hole 118, the viscosity of the raw material liquid 300 to be used, the type of polymer substance in the raw material liquid, and the like. Preferably, when the motor 117 and the outflow body 115 are in direct motion as in the present embodiment, the rotational speed of the motor 117 matches the rotational speed of the outflow body 115.

  The charging device 111 is a device that charges the raw material liquid 300 by applying an electric charge. In the case of the present embodiment, the charging device 111 includes a charging electrode 121, a charging power source 122, and a grounding device 123.

  The charging electrode 121 is a member for inducing charges to the grounded outflow body 115 when the charging electrode 121 is at a high voltage or a low voltage with respect to the ground. In the case of the present embodiment, the charging electrode 121 is an annular member arranged so as to surround the periphery of the outflow body 115. When a positive voltage is applied to the charging electrode 121, a negative charge is induced in the outflow body 115, and when a negative voltage is applied to the charging electrode 121, a positive charge is induced in the outflow body 115. .

  The size of the charging electrode 121 needs to be larger than the diameter of the outflow body 115, and the diameter is preferably selected from a range of 50 mm or more and 1500 mm or less. The shape of the charging electrode 121 is not limited to an annular shape, and may be a polygonal annular shape or a flat plate shape depending on the relationship with the shape of the outflow body 115. Further, the cross-sectional shape of the charging electrode 121 may be not only rectangular but also round.

  The grounding device 123 is a member that is electrically connected to the outflow body 115 and can maintain the outflow body 115 at the ground potential. One end of the grounding device 123 functions as a brush so that the electrical connection state can be maintained even when the outflow body 115 is in a rotating state, and the other end is connected to the ground.

  The charging power source 122 is a power source that can apply a high voltage to the charging electrode 121. In general, the charging power source 122 is preferably a DC power source. In particular, when the charged polarity of the nanofiber 301 is not affected, the charged nanofiber 301 is used to attract the nanofiber 301 with an electrode to which a reverse polarity potential is applied. It is preferable to employ a DC power source. When the charging power source 122 is a direct current power source, the voltage applied by the charging power source 122 to the charging electrode 121 is preferably set from a value in the range of 10 KV or more and 200 KV or less. When a negative voltage is applied to the charging power source 122, the polarity of the applied voltage becomes negative. In particular, the electric field strength between the outflow body 115 and the charging electrode is important, and the applied voltage is adjusted so that the electric field strength is 1 KV / cm or more in the space where the distance between the charging electrode 121 and the outflow body 115 is the closest. Is preferred.

  If an induction method in which one electrode is grounded as the charging device 111 as in the present embodiment is adopted, charge can be imparted to the raw material liquid 300 while the effluent 115 is maintained at the ground potential. If the outflow body 115 is in a ground potential state, it is not necessary to electrically insulate members such as the rotating shaft body 116 and the motor 117 connected to the outflow body 115 from the outflow body 115, and the outflow device 110 has a simple structure. Can be adopted, which is preferable.

  Note that as the charging device 111, a charge may be applied to the raw material liquid 300 by connecting a power source to the effluent body 115, maintaining the effluent body 115 at a high voltage, and grounding the charging electrode 121. In addition, the outflow body 115 is formed of an insulator, and an electrode that directly contacts the raw material liquid 300 stored in the outflow body 115 is disposed inside the outflow body 115, and charges are applied to the raw material liquid 300 using the electrode. It may be a thing. In the case where an electrode is arranged directly on the effluent 115 or directly on the raw material liquid, the polarity of the charge charged in the raw material liquid is the same as the polarity of the applied voltage.

  The gas flow generation device 113 is a device that changes the flight direction of the raw material liquid 300 flowing out from the effluent body 115 and generates a gas flow for transporting the nanofiber 301 and passing the inside of the guide device 102. . In the case of the present embodiment, the gas flow generator 113 is provided on the back portion of the motor 117 and generates a gas flow from the motor 117 toward the tip of the effluent 115. The gas flow generating device 113 can generate wind power that can change the raw material liquid 300 flowing out from the outflow body 115 in the radial direction in the axial direction. In FIG. 2, the gas flow is indicated by arrows. As the gas flow generator 113, a blower provided with an axial fan can be exemplified.

  Note that the gas flow generator 113 may be constituted by another blower such as a sirocco fan. Further, a gas flow may be generated inside the wind tunnel body 112 by the return device 104 described later. In this case, the nanofiber manufacturing apparatus 100 does not have the gas flow generation device 113 that actively generates a gas flow, but the gas flow is generated inside the wind tunnel body 112 or the like by some device. It is assumed that the nanofiber manufacturing apparatus 100 includes the gas flow generation device 113.

  The wind tunnel body 112 is a conduit that guides the gas flow generated by the gas flow generation device 113 between the charging electrode 121 and the outflow body 115. In the case of the present embodiment, the gas flow guided by the wind tunnel body 112 crosses the raw material liquid 300 flowing out from the outflow hole 118 of the outflow body 115 while passing through the inside of the charging electrode 121, and Change the flight direction.

  Furthermore, the discharge device 101 includes a gas flow control device 124 and a heating device 125.

  The gas flow control device 124 has a function of controlling the gas flow so that the gas flow generated by the gas flow generation device 113 does not hit the opening end of the outflow hole 118. In the case of the present embodiment, as the gas flow control device 124, an air passage body that guides the gas flow to flow in a predetermined region is employed. Since the gas flow does not directly hit the outflow hole 118 by the gas flow control device 124, the raw material liquid 300 flowing out from the outflow hole 118 is prevented from evaporating early and blocking the outflow hole 118 as much as possible. The liquid 300 can be kept flowing out stably. The gas flow control device 124 may be a wall-shaped windbreak wall that is disposed on the windward side of the outflow hole 118 and prevents the gas flow from reaching the vicinity of the outflow hole 118.

  The heating device 125 is a heating source that heats the gas constituting the gas flow generated by the gas flow generating device 113. In the case of the present embodiment, the heating device 125 is an annular heater disposed inside the guide body 126, and can heat the gas passing through the heating device 125. By heating the gas flow with the heating device 125, evaporation of the raw material liquid 300 flowing out into the space is promoted, and the nanofiber 301 can be efficiently manufactured.

  The supply path 114 is a path for supplying the raw material liquid 300 to the inside of the outflow body 115 from an external tank for the raw material liquid 300 (not shown). In the case of this embodiment, the supply path 114 is formed of a tubular body.

  FIG. 4 is a perspective view schematically showing the vicinity of the guide device.

  The guide device 102 is a wind tunnel that guides the nanofiber 301 discharged from the discharge device 101 and conveyed by a gas flow to a predetermined place. In the case of the present embodiment, the guide device 102 is a tubular body that is open only at both ends, and includes a guide body 126 and a diffuser 127.

  The guide body 126 has a cylindrical shape, has the same opening shape as the opening shape on the side where the nanofibers 301 of the discharge device 101 are discharged, and is arranged in series with the discharge device 101.

  The diffuser 127 is a conduit that is connected to the guide 126 and diffuses the nanofibers 301 in a high-density state uniformly and uniformly into a low-density state. The space in which the nanofibers 301 are guided is smoothly and continuously. By expanding, it is a hood-like member that gradually reduces the velocity of the gas flow conveying the nanofiber 301 and the velocity of the nanofiber 301. In the case of the present embodiment, the diffuser 127 has a hood shape that maintains the height of the guide body 126 as it is and gradually expands only the width.

  The collection device 103 is a device for collecting the nanofibers 301 emitted from the guide device 102. In the case of the present embodiment, the collection device 103 includes a member to be deposited 128, a winding device 129, and a supply device 130.

  The member 128 to be deposited is a member that separates the nanofiber 301 manufactured by the electrostatic stretching phenomenon and conveyed by the gas flow from the gas flow, and deposits only the nanofiber 301. In the case of the present embodiment, the member 128 to be deposited is a thin and flexible long sheet-like member made of a material that can be easily separated from the deposited nanofibers 301, and easily passes a gas flow. It is a net-like member that can collect the nanofibers 301. Specifically, as the member 128 to be deposited, a long cloth made of aramid fibers can be exemplified. Furthermore, it is preferable to apply a Teflon (registered trademark) coating on the surface of the member 128 to be deposited because the peelability when the deposited nanofiber 301 is peeled off from the member 128 to be deposited is improved. Further, the member to be deposited 128 is supplied from the supply device 130 while being wound in a roll shape.

  The winding device 129 is a device that can transfer the member 128 to be deposited. In the case of the present embodiment, the member to be deposited 128 is transported along with the nanofiber 301 to be deposited while being drawn out from the supply device 130 while winding up the long member to be deposited 128. The winding device 129 can wind up the nanofiber 301 deposited in a nonwoven fabric shape together with the member 128 to be deposited.

  The nanofiber manufacturing apparatus 100 includes an attracting electrode 134 for attracting the charged nanofiber 301 to the deposition target member 128 and an attracting power source 135.

  The attracting electrode 134 is an electrode for generating an electric field for attracting the charged nanofiber 301. In the case of the present embodiment, a metal net capable of passing a gas flow is employed for the attracting electrode 134. The attracting electrode 134 is provided so as to spread over the entire opening of the diffuser 127.

  The attraction power source 135 is a DC power source that can maintain the attraction electrode 134 at a predetermined voltage and polarity. In the case of the present embodiment, the attracting power source 135 is a DC power source that can freely change the voltage and polarity in the range of 0 V (grounded state) to 200 KV or less. In particular, by applying a voltage different from the charged polarity of the charged nanofiber 301 to the attracting electrode 134, recovery of the charged nanofiber 301 toward the attracting electrode 134 can be accelerated.

  In the present embodiment, the attracting electrode 134 is a metal mesh, but the present invention is not limited to this. The attracting electrode 134 is a brush-shaped attracting electrode in which a large number of brushes are formed on a plate-shaped attracting electrode or a metal plate. It may be an electrode. It suffices that the gas flow passes through the deposition target member 128, passes through the vicinity of the attracting electrode, and can be collected by the suction device 132.

(Return to the reference of FIG. 1)
The return device 104 is a device that collects the gas flow that has passed through the deposition target member 128 and returns the gas flow to the gas flow generation device 113. In the case of the present embodiment, the return device 104 includes a concentrating body 131, a suction device 132, and a return body 133.

  The concentrator 131 is a member that receives the gas flow spread by the diffuser 127 and concentrates the gas flow until reaching the suction device 132, and has a funnel shape opposite to the diffuser 127.

  The suction device 132 is a blower that forcibly sucks the gas flow passing through the member 128 to be deposited. The suction device 132 is a blower such as a sirocco fan or an axial fan, and is a device capable of accelerating a gas flow that has passed through the deposition target member 128 and has a reduced velocity to a high velocity.

  The return body 133 is a tube body that can guide the gas flow from the suction device 132 to the gas flow generation device 113.

  As described above, the gas flow generation device 113, the guide device 102, and the return device 104 are connected in a series of rings to form the circulation circuit 200 through which the gas circulates. The return device 104 is provided with a suction device 132, but if either the gas flow generator 113 or the suction device 132 can generate a sufficient gas flow in the circulation circuit 200, The nanofiber manufacturing apparatus 100 may include only one of them. In this case, either one has both the function of the gas flow generation device 113 and the function of the suction device 132. In addition, when a sufficient gas flow cannot be obtained by the gas flow generation device 113 and the suction device 132, a blower or the like that generates a gas flow may be separately arranged in the circulation circuit 200.

  In addition, it is thought that sufficient gas flow is an air volume of about 30 m2 per minute.

  The recovery device 105 is a device that can separate and recover the solvent evaporated from the raw material liquid 300 from the gas flow. The recovery device 105 differs depending on the type of solvent used in the raw material liquid 300. For example, a device that recovers a gas by condensing the solvent at a low temperature, a device that adsorbs only the solvent using activated carbon or zeolite, a liquid Examples thereof include an apparatus for dissolving a solvent in the apparatus and a combination of these apparatuses.

  The separator 107 surrounds the circulation circuit 200 configured by connecting the gas flow generation device 113, the guide device 102, and the return device 104 in a series of rings, and the space where the circulation circuit 200 exists and the other outer space. Walls, floors, and ceilings that isolate them.

  The separator 107 has a function of containing the gas leaking from the circulation circuit 200 circuit in the space surrounded by the separator 107, and thus it is possible to improve the cleanliness and safety of the outer space of the separator 107. Become.

  The introduction device 106 is a device that introduces gas into the inside of the circulation circuit 200 from the outside of the circulation circuit 200 and mixes it with the gas that circulates inside the circulation circuit 200. In the present embodiment, the introduction device 106 is installed through the separator 107 so that the gas outside the separator 107 can be introduced. The introducing device 106 also includes a measuring device (not shown) that measures the volume of gas flowing inward of the circulation circuit 200. If the measurement result of the measuring device is less than 27 m2 per minute, the introducing device 106 A control device (not shown) is provided which can be introduced from the outside of the circulation circuit 200 and can stop the introduction of gas when the measurement result of the measuring device exceeds 33 sq.m. The introducing device 106 may fix the amount of gas introduced to be constant. The introduction device 106 may include only a backflow prevention mechanism that prevents backflow of gas, and the amount of gas introduced may depend on the performance of the gas flow generation device 113 and the suction device 132.

  The exhaust device 108 is a device that exhausts gas from the inner space surrounded by the separator 107 to the outer space. In the case of the present embodiment, the exhaust device 108 has a function of removing the solvent contained in the atmosphere of the inner space of the separator 107.

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

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

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

  The mixing ratio of the solvent and the polymer material varies depending on the solvent and the polymer material, but the amount of the solvent is preferably between about 60 wt% and 98 wt%.

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

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

  First, the gas flow generator 113 and the suction device 132 are operated to generate a gas flow in a certain direction inside the circulation circuit 200 (gas flow generation process) (return process). In the above state, the nanofiber manufacturing apparatus 100 was adjusted so that the air volume in the circulation circuit 200 was 30 m 2 / min. Thereby, a gas flow circulates as follows. Gas flow generator 113 → Guide body 126 → Diffusion body 127 → Deposition member 128 → Concentrated body 131 → Suction device 132 → Recovery device 105 → Return body 133 → Introduction device 106 → Gas flow generator 113

  Next, the raw material liquid 300 is supplied to the inside of the outflow body 115 (raw material liquid supply process). The raw material liquid 300 is separately stored in a tank (not shown), passes through the supply path 114 (see FIGS. 2 and 3), and is supplied into the effluent 115 from the other end of the effluent 115. Specifically, PVA (polyvinyl alcohol) was selected as the material of the nanofiber 301, and the raw material liquid 300 was a solution in which the solvent was water and PVA was dissolved in water at 10% by weight.

  Next, the charging electrode 121 is set to a positive or negative high voltage by the charging power source 122. Charge concentrates on the outflow body 115 arranged at the center of the charging electrode 121, and the charge is transferred to the raw material liquid 300 passing through the outflow hole 118, and the raw material liquid 300 is charged (charging process).

  At the same time as the charging step, the outflow body 115 is rotated by the motor 117, and the charged raw material liquid 300 flows out from the outflow hole 118 by centrifugal force (outflow step).

  Specifically, an effluent 115 having an outer diameter of Φ60 mm was used. The 108 outflow holes 118 were provided at equal intervals in the circumferential direction, and the hole diameter was 0.3 mm. Moreover, the raw material liquid 300 was made to flow out by rotating the outflow body 115 at 2000 rpm. On the other hand, the charging electrode 121 having an inner diameter of Φ600 mm was used, and the charging electrode 121 was made negative 60 KV with respect to the ground potential by the charging power source 122. As a result, a positive charge is induced in the effluent 115, and the positively charged raw material liquid 300 flows out.

  The raw material liquid 300 that has flowed radially in the radial direction of the outflow body 115 is changed in flight direction by the gas flow and is guided to the guide device 102 in the gas flow. Here, since the charged state of the raw material liquid 300 and the charging electrode 121 are opposite in polarity, they are attracted by the Coulomb force and try to fly toward the charging electrode 121, but most of the raw material liquid toward the charging electrode 121. The direction of 300 is changed by the gas flow, and the aircraft 300 flies toward the guide body.

  The raw material liquid 300 is discharged from the discharge device 101 while manufacturing the nanofiber 301 by the electrostatic stretching phenomenon (nanofiber manufacturing process). Here, since the raw material liquid 300 flows out in a strong charged state (high charge density), electrostatic stretching easily occurs, and most of the raw material liquid 300 that flows out changes to the nanofibers 301. In addition, since the raw material liquid 300 flows out in a strongly charged state (high charge density), electrostatic stretching occurs over many orders, and a large amount of nanofibers 301 having a small wire diameter are manufactured.

  The gas flow is heated by the heating device 125, and while guiding the flight of the raw material liquid 300, heat is applied to the raw material liquid 300 to promote evaporation of the solvent and promote electrostatic stretching.

  The nanofiber 301 emitted from the emission device 101 as described above is introduced into the guide device 102. Then, the nanofiber 301 is guided toward the collection device 103 while being conveyed in the gas flow inside the guide device 102 (conveying step).

  The nanofibers 301 transported to the diffuser 127 are rapidly reduced in speed and are uniformly dispersed (diffusion process).

  In this state, the suction device 132 disposed behind the member 128 to be deposited sucks the gas flow together with the solvent that is the evaporated component, and attracts the nanofiber 301 onto the member 128 to be deposited (attraction process). . In addition, an electric field is generated by the attracting electrode 134 to which a voltage is applied, and the nanofiber 301 is also attracted by the electric field (attraction process).

  As described above, the nanofiber 301 is collected by being separated from the gas flow by the deposition target member 128 (collecting step). Since the member to be deposited 128 is slowly transferred by the winding device 129, the nanofiber 301 is also collected as a long belt-like member extending in the transfer direction.

  The gas flow that has passed through the deposition target 128 is accelerated by the suction device 132 and reaches the recovery device 105. The recovery device 105 separates and recovers the solvent component from the gas stream (recovery process).

  The gas flow that has passed through the recovery device 105 passes through the return body 133 and is returned to the gas flow generation device 113 through the introduction device 106 (returning step). Thereby, the gas flow in which the concentration of the solvent is lowered is again supplied to the nanofiber 301 by the gas flow generator 113.

  When the air volume of the gas flow is insufficient, the introduction device 106 introduces outside air (introduction process) to compensate for the shortage.

  The shortage of air volume is the amount of gas leaked from the circulation circuit 200 to the outside. The gas is discharged to the inside of the separator 107, and the exhaust device 108 exhausts the solvent to the outer space while collecting the solvent (exhaust process).

  By using the nanofiber manufacturing apparatus 100 having the above-described configuration and performing the above nanofiber manufacturing method, the gas flow used for changing the flight direction of the raw material liquid 300 and transporting the nanofiber 301 is changed to nanofiber manufacturing. It becomes difficult to leak outside the apparatus 100. Therefore, it is possible to maintain a favorable environment such as a factory where the nanofiber manufacturing apparatus 100 is installed.

  Further, since the gas is circulated in the circulation circuit 200, it is only necessary to compensate for the loss by the gas flow generator 113 and the suction device 132 in order to maintain the air volume of the gas flow. Therefore, it is possible to suppress an increase in running cost for maintaining the gas flow with a predetermined air volume and contribute to energy saving.

  Moreover, since it is not necessary to introduce a large amount of gas from the outside and exhaust a large amount of gas, it is not necessary to secure a large space for introducing the gas into the factory, and the installation space of the nanofiber manufacturing apparatus 100 can be reduced. Can be achieved.

  Since the solvent is always recovered by the recovery device 105, the concentration of the circulating gas solvent does not exceed a predetermined value, and it is possible to prevent evaporation of the raw material liquid 300 or reach the explosion concentration as much as possible. It can be avoided.

  In the above embodiment, the raw material liquid 300 is caused to flow out using centrifugal force, but the present invention is not limited to this. For example, as shown in FIG. 5, the raw material liquid 300 may be discharged from the outflow hole 118 by the pressure applied to the raw material liquid 300. Specifically, the nanofiber manufacturing apparatus 100 has a rectangular parallelepiped wind tunnel body 112 that is open at both ends, and a plurality of nozzles that are provided on one wall surface of the wind tunnel body 112 and that have outlet holes 118 provided at the tip. The outflow body 115, the gas flow generating device 113 provided at one end opening of the wind tunnel body 112, and the charging electrode 121 provided as a part of the wind tunnel body 112 on the surface facing the outflow body 115 may be provided.

  As shown in FIG. 6, a plurality of discharge devices 101, guide devices 102, and collection devices 103 are arranged side by side, and a return device 104, a recovery device 105, and an introduction device 106 are commonly used for the plurality of devices. It doesn't matter. Further, these may be installed in one space surrounded by the separator 107 and the exhaust device 108 may be used in common.

  Further, in the middle of the circulation circuit 200, a humidity control device 141 or a temperature control device 142 that adjusts the humidity and temperature of the gas may be provided.

  Further, a plurality of emission devices 101 may be arranged so that the nanofibers 301 flow into the guide body 126 to generate a large amount of nanofibers 301. In such a case, a branch passage may be provided from the introduction device 106 to each discharge device 101 so that an appropriate amount of air flows into each discharge device 101.

  In the embodiment of the present application, the configuration in which the charging electrode 121 is disposed at a position facing the outflow body 115 is shown. However, the present invention is not limited thereto, and the charging electrode 121 is removed. A potential difference may be provided between the attracting electrodes 134 to charge the raw material liquid 300 flowing out from the outflow hole 118 of the outflow body 115, and the same effect as disclosed in the present invention can be obtained.

  The present invention can be used for the manufacture of nanofibers, the manufacture of nonwoven fabrics made of nanofibers, and the manufacture of yarns made of nanofibers.

It is a top view which cuts off and shows part of embodiment of a nanofiber manufacturing apparatus. It is a top view which notches and shows a part of discharge | release apparatus. It is a perspective view which shows the external appearance of the discharge | release apparatus. It is a perspective view which shows typically the vicinity of a guide apparatus. It is sectional drawing which shows other embodiment of discharge | release apparatus. It is a block diagram which shows another example of a nanofiber manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Nanofiber manufacturing apparatus 101 Discharge apparatus 102 Guide apparatus 103 Collection apparatus 104 Return apparatus 105 Recovery apparatus 106 Introduction apparatus 107 Separator 108 Exhaust apparatus 110 Outflow apparatus 111 Charging apparatus 112 Wind tunnel body 113 Gas flow generation apparatus 114 Supply path 115 Outflow body 116 Rotating shaft 117 Motor 118 Outflow hole 119 Bearing 120 Insulator 121 Charging electrode 122 Charging power source 123 Grounding device 124 Gas flow control device 125 Heating device 126 Guide body 127 Diffuser 128 Deposited member 129 Winding device 130 Supply device 131 Concentrating body 132 Suction Device 133 Returning Body 134 Attracting Electrode 135 Attracting Power Supply 141 Humidity Controlling Device 142 Temperature Controlling Device 200 Circulating Circuit 300 Raw Material Liquid 301 Nanofiber

Claims (5)

A nanofiber manufacturing apparatus for manufacturing nanofibers by stretching a raw material liquid in space,
An outflow body having an outflow hole for flowing the raw material liquid into the space;
A charging device for charging the raw material liquid;
A gas flow generator for generating a gas flow for transporting nanofibers produced from the raw material liquid flowing out of the effluent, and
A guiding device for guiding the nanofiber together with the gas flow;
A collection device for collecting the nanofibers by separating the gas flow and the nanofibers;
A return device for returning a gas flow to the gas flow generator;
A nanofiber manufacturing apparatus comprising: a recovery device that separates and recovers a solvent evaporated from a raw material liquid from a gas stream. further,
The nanofiber manufacturing apparatus according to claim 1, further comprising an introduction device that introduces gas from outside into a circulation circuit including the guide device and the return device. further,
An isolator that surrounds the circulation circuit and isolates the space in which the circulation circuit exists and the other external space;
An exhaust device for exhausting gas from the inner space surrounded by the separator to the outer space;
The nanofiber manufacturing apparatus according to claim 2, wherein the introduction device introduces a gas from an outer space into the circulation circuit. A nanofiber production method for producing a nanofiber by stretching a raw material liquid in a space,
An outflow process for flowing the raw material liquid into the space;
A charging step for charging the raw material liquid;
A gas flow generating step for generating a gas flow for transporting nanofibers manufactured from the raw material liquid flowing out from the effluent, and
A guiding process for guiding the nanofiber together with the gas flow;
A collecting step of collecting the nanofibers by separating the gas flow and the nanofibers;
A return step for returning the gas flow to the gas flow generator;
And a recovery step of separating and recovering the solvent evaporated from the raw material liquid from the gas flow.   The nanofiber manufacturing method according to claim 4, wherein the gas flow generation step includes an introduction step of introducing a new gas.

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