JP5235733B2 - Nanofiber manufacturing apparatus and nanofiber manufacturing method - Google Patents

Description

  The present invention relates to a nanofiber manufacturing apparatus and a nanofiber manufacturing method for manufacturing a fiber (nanofiber) having submicron order fineness by an electrostatic stretching phenomenon.

  As a method for producing a thread-like (fibrous) substance made of a resin or the like and having a submicron-scale diameter, a method using an electrostatic stretching phenomenon (electrospinning) is known.

  This electrostatic stretching phenomenon means that a raw material liquid in which a solute such as a resin is dispersed or dissolved in a solvent is discharged (injected) into the space by a nozzle or the like, and an electric charge is applied to the raw material liquid to charge the space. This is a method of obtaining nanofibers by electrically stretching a raw material liquid in flight.

  The electrostatic stretching phenomenon will be described more specifically as follows. That is, the raw material liquid that has been 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 when the repulsive Coulomb force generated in the raw material liquid exceeds the surface tension of the raw material liquid, the raw material liquid explodes. The phenomenon that the film is stretched linearly occurs. This is the electrostatic stretching phenomenon. This electrostatic stretching phenomenon occurs geometrically in the space one after another, so that nanofibers made of a resin having a diameter of submicron order are manufactured.

  As an apparatus for producing nanofibers using the electrostatic stretching phenomenon as described above, the inventors of the present application have proposed an electrode for charging a raw material liquid at a predetermined distance from an outflow body that is a member through which the raw material liquid flows out. Conventionally, a device in which the charging electrode is arranged has been proposed.

  Thereby, the freedom degree of design, such as arrangement | positioning of an effluent body and an electrode, and each shape, improves, It has come to be able to provide the nanofiber manufacturing apparatus which can manufacture a nanofiber efficiently (for example, Patent Document 1).

  In order to efficiently charge the raw material liquid in the nanofiber manufacturing apparatus, it is preferable to dispose the outflow body and the charging electrode close to each other. However, since the polarity of the charging electrode and the polarity of the charged raw material liquid are different, the raw material liquid and nanofibers are likely to adhere to the charging electrode.

Therefore, a nanofiber manufacturing apparatus that can prevent the raw material liquid and the nanofiber from adhering to the charging electrode by conveying the raw material liquid and the nanofiber by a gas flow has been separately proposed.
JP 2009-41128 A

  The inventors of the present application have further conducted intensive experiments and research for the purpose of reducing the adhesion of the raw material liquid and nanofiber to the charging electrode and improving the production efficiency of the nanofiber. The inventors have found a nanofiber manufacturing apparatus that can realize a combination of shape and gas flow control.

  This invention is made | formed based on the said knowledge.

  In order to achieve the above object, a nanofiber manufacturing apparatus according to the present invention is a nanofiber manufacturing apparatus that manufactures nanofibers by electrically stretching a raw material liquid in a space. An outflow body having an outflow hole to be discharged, a charging electrode arranged at a predetermined interval from the outflow body, the charging electrode having a convex curved surface portion on a surface facing the outflow body, and the surface A blower that generates a laminar flow of gas immediately above the unit, and a charging power source that applies a predetermined voltage between the outflow body and the charging electrode.

  According to this, it becomes possible to forcibly convey the raw material liquid and nanofibers approaching the charging electrode to another place by the laminar flow generated immediately above the charging electrode. Therefore, the amount of the raw material liquid and nanofibers attached to the charging electrode can be reduced as much as possible, and the production efficiency of nanofibers can be improved.

  Further, the outflow body has a cylindrical shape, the outflow hole is provided in a peripheral wall of the outflow body, the charging electrode has an annular shape, and is disposed so as to surround the outflow body, It is preferable to provide an annular air outlet along the charging electrode.

  As a result, a large amount of raw material liquid can flow out into the space at a time, and charges can be efficiently applied to the raw material liquid. In addition, it is possible to reduce the amount of raw material liquid and nanofibers attached to the charging electrode. Accordingly, it is possible to produce a large amount of nanofibers with high production efficiency.

Furthermore, it is preferable to provide a drive device for rotating the outflow body.
Thereby, the raw material liquid which flows out in space can be made into a uniform state, and it becomes possible to make the quality of the nanofiber manufactured uniform.

  Moreover, in order to achieve the said objective, the nanofiber manufacturing method concerning this invention is a nanofiber manufacturing method which electrically stretches a raw material liquid in space, and manufactures nanofiber, Comprising: An effluent has An outflow step for flowing the raw material liquid into the space from the outflow hole, and a charging electrode disposed at a predetermined interval from the outflow body, the charging electrode having a convex curved surface portion facing the outflow body The method includes a charging step of applying a predetermined voltage between the electrode and the outflow body, and a blowing step of generating a laminar flow of gas immediately above the surface portion.

  According to this, it becomes possible to forcibly convey the raw material liquid and nanofibers approaching the charging electrode to another place by the laminar flow generated immediately above the charging electrode. Therefore, the amount of the raw material liquid and nanofibers attached to the charging electrode can be reduced as much as possible, and the production efficiency of nanofibers can be improved.

  It is possible to prevent the raw material liquid and nanofibers from adhering to the charging electrode and improve the production efficiency of the nanofibers.

  Next, a nanofiber manufacturing apparatus and a resin changing method according to the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing 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 body 102, a collection device 103, and an attracting device 104.

  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 second blower device 113, a supply device 107, and a blower device 137.

  The outflow device 110 is a device for causing the supplied raw material liquid 300 to flow out into the space by centrifugal force without being brought into contact with air, and is an apparatus for applying a charge to the raw material liquid 300 and charging it. In the present embodiment, the outflow device 110 includes an outflow body 115, a shaft body 116, and a drive device 117.

  The outflow body 115 is a member for causing the raw material liquid 300 to flow into the space by the pressure and centrifugal force of the raw material liquid 300, and is connected to the shaft body 116 in a liquid-tight state and rotatable relative to the shaft body 116. It is a hollow member. An outflow hole 118 is provided in the peripheral wall of the outflow body 115. When the nanofiber 301 is manufactured, the outflow body 115 is filled with the raw material liquid 300, and the raw material liquid 300 is caused to flow out into the space by the pressure of the raw material liquid 300 and the centrifugal force due to its rotation. It is a possible member. In the case of the present embodiment, the outflow body 115 has a cylindrical shape with one end closed, and the peripheral wall includes a number of outflow holes 118 through which the raw material liquid 300 flows out from the inside of the outflow body 115 to the outside. ing. In addition, the outflow body 115 is formed of a conductor in order to impart electric charge to the stored raw material liquid 300.

  In the case of the present embodiment, the outflow body 115 can be separated into the rotating base 119 and the lid 120. This is for the purpose of facilitating maintenance such as cleaning the inside of the outflow body 115 by separating the lid 120 from the rotating base 119.

  The rotating base 119 is a cylindrical member that is restricted in relative movement with the shaft body 116 in the axial direction and is rotatably connected to the shaft body 116. In the case of the present embodiment, the rotating base 119 is connected to the shaft body 116 via a bearing 109 and is attached to the shaft body 116 so as to be rotatable. The rotating base 119 is connected to the outer peripheral wall of the shaft body 116 via a packing 106 that can rotate and slide and can maintain the sliding portion in a liquid-tight manner. Thereby, the outflow body 115 can be connected to the shaft body 116 in a liquid-tight state and rotatably with respect to the shaft body 116.

  The lid 120 is a member that is detachably attached to the rotating base 119 and closes the storage chamber 108 that stores the raw material liquid 300 so as to be openable and closable. In the case of the present embodiment, the lid 120 is a cylindrical body whose one end is closed, and an outflow hole 118 is provided in the peripheral wall of the lid 120. Thus, the storage chamber 108 can be easily cleaned by allowing the storage chamber 108 of the outflow body 115 storing the raw material liquid 300 to be opened by attaching and detaching the lid 120. Further, by providing the outflow hole 118 in the lid 120, a cleaning method such as immersing the lid 120 removed from the outflow body 115 in a solvent and applying ultrasonic waves can be easily selected. The inner wall can also be easily cleaned.

  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 to employ the diameter of the outflow body 115 from the range of 20 mm or more and 150 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. Further, it is preferable that the outflow hole 118 has a short hole length. This is because it is easy to remove the resin blocking the outflow hole 118 during maintenance.

  The shape of the outflow body 115 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 shaft body 116 is a member that is connected to the outflow body 115 in a rotatable and liquid-tight state, and has a guide tube 114 (described later) inserted therein and connected to the guide tube 114 in a liquid-tight state. In the case of the present embodiment, the shaft body 116 is a cylindrical member that functions as a rotating shaft body of the outflow body 115, and the outflow body 115 rotates around the shaft body 116. One end opening of the shaft body 116 faces the storage chamber 108 of the outflow body 115, and the other end is fixed to the base.

  The driving device 117 is a device that applies a rotational driving force to the outflow body 115 in order to cause the raw material liquid 300 to flow out from the outflow hole 118 by centrifugal force. In the case of the present embodiment, the driving device 117 includes a belt drive mechanism and a motor, and applies a rotational force to the outflow body 115 by rotating a pulley attached to the rotating base 119 of the outflow body 115 with a belt. ing. In this way, by transmitting the driving force through the belt drive mechanism, the motor and the outflow body 115 can be insulated.

  The driving device 117 may include a hollow shaft motor, and the shaft body 116 may be inserted inward of the hollow shaft, and the outflow body 115 may be directly rotated by the hollow shaft.

  The rotational speed of the outflow body 115 may be 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. preferable.

  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 that is arranged at a predetermined interval from the effluent body 115 and induces electric charges to the effluent body 115 by itself becoming a high voltage or a low voltage with respect to the effluent body 115. In the case of the present embodiment, the charging electrode 121 is an annular member disposed 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. .

FIG. 4 is a cross-sectional view showing the charging electrode and the blower 137.
As shown in the figure, the charging electrode 121 includes a convex curved surface 144 on the surface facing the outflow body 115.

  In the case of the present embodiment, the size of the charging electrode 121 needs to be larger than the diameter of the outflow body 115, but the diameter is preferably adopted from the 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. In addition, as long as the cross-sectional shape of the charging electrode 121 includes the convex curved surface portion 144, the shape of other portions is not particularly limited. In addition, the convex curved shape means that the flow of a gas blown from a blower 137 described later and the surface portion 144 of the charging electrode 121 cooperate with each other to follow the shape of the surface portion 144 to a certain degree directly above the surface portion 144. It is the shape which can generate the laminar flow W1 (the flow of the laminar gas whose flow velocity is faster than the gas flow W2 of the other part). For example, the cross-sectional shape including the surface portion 144 of the charging electrode 121 is similar to the cross-sectional shape of an airplane wing. The effect that the laminar flow W1 is generated is referred to as a “Coanda effect”, and it can also be said that the charging electrode 121 has a curved surface shape that can generate the Coanda effect. As long as this is the case, the cross-sectional shape of the charging electrode 121 may be circular or elliptical.

  In the present embodiment, 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 grounding device 123 only needs to be electrically connected to the outflow body 115, and the rotating outflow body 115 and the grounding device 123 may be slightly separated from each other.

  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. Is preferably a DC power supply. 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 to 200 KV. 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 shaft body 116 and the driving device 117 connected to the outflow body 115 from the outflow body 115, and the outflow apparatus 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.

  The blower 137 is a device that can generate a laminar flow of gas immediately above the surface portion 144 of the charging electrode 121. In the case of the present embodiment, a compressor 139 (see FIGS. 1 and 4) and a blower 138 are provided.

  The compressor 139 is a so-called air compressor capable of boosting air to a predetermined pressure and sending it out.

  The air blowing unit 138 is a nozzle that includes the air blowing port 145 and jets the pressurized air along the surface portion 144 of the charging electrode 121. In the case of the present embodiment, the air blowing unit 138 has an annular shape along the charging electrode 121. The shape of the air blowing unit 138 may be any shape as long as the Coanda effect is generated directly above the surface portion 144 of the charging electrode 121.

  Note that the gas flow generated by the blower 137 is not limited to air but may be, for example, an inert gas such as nitrogen, or any gas such as superheated steam. The blower 137 may supply gas from a cylinder filled with gas at a high pressure to generate a gas flow.

  The second air blower 113 changes the flight direction of the raw material liquid 300 flowing out from the outflow body 115, and transports the nanofiber 301 to pass the inside of the guide body 102 (in FIG. 4, W2). ). In the case of the present embodiment, the second blower 113 generates a gas flow from the base 154 side toward the tip of the outflow body 115. The 2nd air blower 113 can generate the wind force which can change the raw material liquid 300 discharged | emitted from the outflow body 115 to an axial direction to an axial direction. In FIG. 2, the gas flow is indicated by arrows. In the case of this Embodiment, the 2nd air blower 113 is comprised with the axial flow fan.

In the present invention, the second air blower 113 may not be provided in the nanofiber manufacturing apparatus 100. However, the Bernoulli effect may be generated by the laminar flow W <b> 1 by the blower 137 and a gas flow may be generated inside the wind tunnel body 112. In this case, the nanofiber manufacturing apparatus 100 does not have the second air blowing device 113 that actively generates a gas flow, but can obtain the same effect as when the second air blowing device 113 exists. There is.
In addition, the nanofiber manufacturing apparatus 100 may include the second air blower 113 when a gas flow is generated inside the wind tunnel body 112 or the like by a suction device 132 described later or some other device. . Further, the second blower 113 may be constituted by another blower such as a sirocco fan.

  Furthermore, the discharge device 101 includes a wind tunnel body 112, a wind control body 124, and a heating device 125.

  The wind tunnel body 112 is a wind tunnel that rectifies the gas flow (other than the laminar flow W1) flowing in the space near the outflow body 115 so as to obtain a desired flow. In the case of the present embodiment, it is a conduit for guiding the gas flow generated in the second blower 113 between the charging electrode 121 and the effluent body 115. 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 changes the flight direction of the raw material liquid 300.

  The wind control body 124 has a function of controlling the gas flow so that the gas flow generated by the second blower 113 does not hit the open end of the outflow hole 118. In the case of the present embodiment, an air passage body that guides a gas flow to flow in a predetermined region is adopted as the wind control body 124. Since the gas flow does not directly hit the outflow hole 118 by the wind control body 124, the raw material liquid 300 flowing out from the outflow hole 118 is prevented from evaporating at an early stage and blocking the outflow hole 118 as much as possible. It becomes possible to keep 300 flowing out stably. The wind control body 124 may be a wall-shaped windbreak wall that is arranged 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 second blower device 113. In the case of the present embodiment, the heating device 125 is an annular heater disposed inside the guide body 102 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.

FIG. 5 is a diagram schematically showing a part of the supply device with a part cut away.
As shown in the figure, the supply device 107 includes a container 151, a booster 153, and a lead-out pipe 156, and a second container 152, a transfer device 155, an on-off valve 159, a guide pipe 114, and the like. It has. The supply device 107 includes a weight measuring device 141 and a control device 142.

  The container 151 is a container that can store the raw material liquid 300 and can maintain airtightness against the pressure of the gas supplied from the pressure increasing device 153. Note that a lead-out pipe 156, an introduction pipe 157, and a gas introduction pipe 158 are inserted into the container 151.

  Since the container 151 is in an airtight state, the raw material liquid 300 can be pumped from the outlet pipe 156 by gas pressure. Further, since the container 151 is in an airtight state, it is possible to suppress the solvent from evaporating from the raw material liquid 300, and since the pressure inside the container 151 is increased, the evaporation of the solvent can be further suppressed. Therefore, it is possible to stably pump the effluent 115 without reducing the quality of the raw material liquid 300.

  The pressure increasing device 153 is a device that introduces gas into the container 151 and raises the pressure in the container 151. In the case of this embodiment, the booster 153 includes a pressure source 161 and a regulating valve 162. The pressure source 161 is a device such as a cylinder or an accumulator in which high-pressure gas is sealed, for example. The regulating valve 162 is a so-called regulator that can lower the pressure of the pressure source 161 to a predetermined pressure. The gas used for the booster 153 is not particularly limited. For example, an inert gas such as air or nitrogen can be exemplified.

  The lead-out tube 156 is a tubular member that is disposed in a state where one open end is immersed in the raw material liquid 300 stored in the container 151.

  The second container 152 is a container having a larger capacity than the container 151, and can store a large amount of the raw material liquid 300.

  The transfer device 155 is a device for transferring the raw material liquid 300 from the second container 152 to the container 151. An example of the transfer device 155 is a pump.

  The on-off valve 159 is an electromagnetic valve that can select whether or not to pass the raw material liquid 300 supplied from the transfer device 155.

  The guide tube 114 is a tube that guides the raw material liquid 300 fed from the supply device 107 to the outflow body 115. In the case of the present embodiment, the distal end portion of the guide tube 114 is provided in the shaft body 116 and is provided with a diameter-expanded portion 126 that is expanded by the pressure of the raw material liquid. When the raw material liquid 300 is inserted into the guide tube 114, the diameter-expanded portion 126 is expanded to come into contact with the shaft body 116 and are connected in a liquid-tight state. When the raw material liquid 300 is not inserted into the guide tube 114, the guide tube 114 can be easily inserted into and extracted from the shaft body 116.

  The weight measuring device 141 is a device for measuring the weight of the container 151 to be placed, the raw material liquid 300 to be accommodated, and the like, and can transmit the measurement result as information.

  The control device 142 analyzes the information received from the weight measuring device 141, and when the information obtained from the weight measuring device 141 includes information equal to or less than a predetermined weight, the control device 142 controls the on-off valve 159 to change the raw material liquid 300. It is a device that can be supplied to the inside of the container 151.

FIG. 6 is a perspective view showing the vicinity of the guide body.
As shown in the figure, the guide body 102 is a wind tunnel that guides the nanofiber 301 that is discharged from the discharge device 101 and conveyed by the gas flow to a predetermined place.

  The diffuser 127 is a conduit that is connected to the guide body 102 and diffuses the nanofibers 301 conveyed in a high density state in the space uniformly and in a low density state, and smoothes the space in which the nanofibers 301 are guided. And it is a hood-like member which gradually decelerates the speed of the gas flow which conveys nanofiber 301, and the speed of nanofiber 301 by expanding continuously. In the case of the present embodiment, the diffuser 127 has a hood shape that maintains the height of the guide body 102 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 body 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 member 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 deposition target member 128 is supplied from the member supply device 130 in a state of 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 together with the nanofibers 301 to be pulled out from the member supply device 130 while winding 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.

  As shown in FIG. 1, the attracting device 104 is a device for attracting the nanofiber 301 to the deposition target member 128. In the case of the present embodiment, the attracting device 104 includes a gas attracting device 143 and an electric field attracting device 133 so that different attracting methods can be performed simultaneously or selectively.

  The gas attracting device 143 is a device that attracts the nanofiber 301 to the deposition target member 128 by sucking a gas flow, and is disposed behind the deposition target member 128. In the case of the present embodiment, the gas attracting device 143 includes a suction device 132 and a concentrating body 131.

  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. By sucking the gas flow with the suction device 132, the solvent that evaporates when the nanofiber 301 is manufactured is also sucked at the same time. By doing so, even when a highly flammable solvent is used, the inside of the guide body 102 does not reach the explosion concentration, and the apparatus can be used with confidence.

  The electric field attracting device 133 is a device that attracts the charged nanofiber 301 to the deposition target member 128 by an electric field, and includes an attracting electrode 134 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 addition, although the metal mesh is employ | adopted for the attracting electrode 134 in embodiment, it is not limited to it. For example, a rod-like body having a predetermined width and a length approximately equal to the width of the member to be deposited 128 may be used. A plurality of rod-like attracting electrodes 134 may be arranged.

When the charging power source 122 is an AC power source, the attracting power source 135 may be an AC power source.
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.

  Here, as the resin constituting the nanofiber 301, polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, polyfluoride. Vinylidene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, polyamide, aramid, polyimide , Polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, Ripepuchido etc. and can be exemplified a polymer material such as a copolymer thereof. 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 resin.

  Examples of the solvent used for the raw material liquid 300 include volatile organic solvents. Specific examples are methanol, ethanol, 1-propanol, 2-propanol, hexafluoroisopropanol, tetraethylene glycol, triethylene glycol, dibenzyl alcohol, 1,3-dioxolane, 1,4-dioxane, methyl ethyl ketone, methyl isobutyl. Ketone, methyl-n-hexyl ketone, methyl-n-propyl ketone, diisopropyl ketone, diisobutyl ketone, acetone, hexafluoroacetone, phenol, formic acid, methyl formate, ethyl formate, propyl formate, methyl benzoate, ethyl benzoate, benzoate Propyl acid, methyl acetate, ethyl acetate, propyl acetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, methyl chloride, ethyl chloride, methylene chloride, chloroform, o-chloroto Ene, p-chlorotoluene, chloroform, 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, N, N-dimethylacetamide, dimethylsulfoxide, pyridine, water Etc. can be listed. 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 the raw material liquid 300 used for this invention is not limited to employ | adopting 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 the substance added to the raw material liquid 300 of this invention is not limited to the said additive.

  Although the mixing ratio of the solvent and the resin in the raw material liquid 300 varies depending on the type of the solvent and the type of the resin, the amount of the solvent is preferably between about 60 wt% and 98 wt%.

  As in the present embodiment, when the raw material liquid 300 and the manufactured nanofibers 301 are transported by a gas flow, and the gas flow is sucked by the suction device 132, the solvent vapor flows without stagnation. Even if it is the raw material liquid 300 containing 50 weight% or more, it will fully evaporate and it will become possible to generate an electrostatic stretching phenomenon. Therefore, since the nanofiber 301 can be manufactured from a state in which the concentration of the resin that is a solute is low, it is also possible to manufacture a thinner nanofiber 301. Moreover, since the adjustable range of the raw material liquid 300 is widened, the performance range of the manufactured nanofiber 301 can be widened.

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

  First, the blower 137 is operated to generate a laminar gas flow W <b> 1 immediately above the surface portion 144 of the charging electrode 121. Specifically, high-pressure air is ejected from the air blowing port 145 of the air blowing unit 138. As a result, the Coanda effect is generated and a laminar flow W1 is generated (air blowing process).

  Next, the second air blower 113 and the suction device 132 are operated, and the gas flow from the discharge device 101 to the collection device 103 is inward of the wind tunnel body 112, the guide body 102, the diffusion body 127, and the concentration body 131. Generate (second blowing process).

  In the above-described state, the nanofiber manufacturing apparatus 100 was adjusted so that the air volume of the gas flow W2 in the guide body 102 was 30 sq.m per minute. In addition, the wind speed of the laminar flow W1 was 10 times or more of the gas flow W2.

  Next, a gas having a predetermined pressure is introduced into the container 151 from the booster 153. In the case of the present embodiment, by monitoring the weight of the container 151 and appropriately supplying the raw material liquid 300 from the second container 152 to the container 151, a certain amount of the raw material liquid 300 is always stored in the container 151. . In addition, air was used as the gas introduced from the booster 153. Thereby, the pressure inside the container 151 is increased, and the raw material liquid 300 is always led out from the outlet pipe 156 at a constant pressure.

  The raw material liquid 300 led out from the container 151 passes through the guide tube 114 and is pumped to the storage chamber 108 of the effluent 115. Here, the outlet tube 156, the guide tube 114, and the outflow body 115 are connected in series, and the raw material liquid 300 is supplied to the storage chamber 108 of the outflow body 115 without being exposed to air.

  If the capacity of the container 151 is sufficient, the container 151 may be operated with the on-off valve 159 kept closed. This is because the sealed state can be maintained when the liquid level is pressed at a predetermined pressure.

  The raw material liquid 300 supplied to the outflow body 115 fills the storage chamber 108 and flows out from the outflow hole 118 into the space (supply process). As described above, the raw material liquid 300 reaches the outflow hole 118 from the supply device 107 without touching the air.

  Polyurethane was selected as the solute resin employed in the present embodiment. Further, N, N-dimethylacetamide was selected as the solvent constituting the raw material liquid 300. The mixing ratio of the solute and the solvent in the raw material liquid 300 was 25% by weight of polyurethane and 75% by weight of N, N-dimethylacetamide.

  Next, the charging electrode 121 is set to a positive or negative high voltage by the charging power source 122. Charge concentrates in the outflow hole 118 of the outflow body 115 arranged in the vicinity of the charging electrode 121, and the charge passes through the outflow hole 118 of the outflow body 115 and is transferred to the raw material liquid 300 which flows into the space. 300 is charged (charging process).

  At the same time as the charging step, the driving body 117 rotates the outflow body 115, and the raw material liquid 300 flows out into the space with a predetermined pressure and centrifugal force from the outflow hole 118 provided in the peripheral wall of the outflow body 115 (rotation process). Spill process).

  Specifically, an effluent 115 having an outer diameter of Φ60 mm was used. The outflow body 115 is provided with 72 outflow holes 118 at equal intervals in the circumferential direction. The diameter of the outflow hole 118 was 0.2 mm, and the shape was circular. 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 out of the outflow hole 118 first comes into contact with the gas flow (air), is conveyed by the gas flow (conveying step), and is guided to the guide body 102 by riding on the gas flow.

  Here, since the charged state of the raw material liquid 300 and the charging electrode 121 are opposite in polarity, the raw material liquid 300 that is attracted by the Coulomb force to fly toward the charging electrode 121 is The direction is changed by the gas flow W2, and the aircraft flies toward the guide body 102. Further, the direction of the raw material liquid 300 and the nanofiber 301 that are going to the charging electrode 121 is changed by the laminar flow W1. Therefore, it is possible to avoid as much as possible that the raw material liquid 300 and the nanofibers 301 adhere to the charging electrode 121, and to improve the production efficiency (yield) of the nanofibers 301.

  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 with a small wire diameter are manufactured.

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

  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 deposition target member 128 sucks the gas flow together with the evaporated solvent, and attracts the nanofiber 301 onto the deposition target member 128 (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 from the gas flow (recovery process).

  By using the nanofiber manufacturing apparatus 100 configured as described above and performing the above nanofiber manufacturing method, the raw material liquid 300 can be supplied without being exposed to air until it flows out from the outflow hole 118. Stable quality raw material liquid 300 can continue to flow into the space, and high-quality nanofibers 301 can be manufactured in a stable state for a long period of time. Further, the resin in the raw material liquid 300 can be prevented from solidifying in the outflow hole 118, and the number of maintenance operations for removing clogging of the outflow hole 118 can be reduced.

  Further, since the raw material liquid 300 flows out from the outflow holes 118 due to the pressure of the raw material liquid 300 together with the centrifugal force, the raw material liquid 300 flows out from each outflow hole 118 evenly, and the quality of the manufactured nanofibers 301 can be stabilized. It becomes possible.

FIG. 7 is a cross-sectional view showing another embodiment of the discharge device.
As shown in the figure, the charging electrode 121 is an annular member having a circular cross section. On the other hand, the discharge device 101 is not provided with the second blower device 113.

  Even in the discharge device 101 as described above, a laminar flow W1 is generated by the Coanda effect, and a gas flow W2 for transporting the nanofiber 301 is generated by the Bernoulli effect by the laminar flow W1.

FIG. 8 is a cross-sectional view showing another embodiment of the discharge device.
As shown in the figure, the outflow body 115 is a rectangular member in which a large number of nozzles 169 are arranged in a matrix, and the raw material liquid 300 is brought into the space by the pressure of the raw material liquid 300 supplied from the guide tube 114. It will leak.

  The charging electrode 121 is a plate-like member having a size that can cover all of the many nozzles 169 arranged in a matrix, and a convex curved surface portion 144 is provided on the surface facing the outflow body 115. It has been.

  Further, on the upstream end side of the charging electrode 121, an elongated air blower 138 extending in the depth direction (perpendicular to FIG. 8) is provided.

  As described above, even if the shapes of the effluent 115 and the charging electrode 121 have various forms, if the laminar flow W1 is generated by the blower 137, the raw material liquid 300 and the nanofibers 301 attached to the charging electrode 121 The amount can be reduced, and the production efficiency of the nanofiber 301 can be improved.

  The present invention can be used for producing nanofibers, spinning using nanofibers, and producing nonwoven fabrics.

It is a top view which notches and shows a nanofiber manufacturing apparatus partially. 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 sectional drawing which shows a charging electrode and the air blower 137. It is a figure which cuts off a part of supply apparatus and shows typically. It is a perspective view which shows the guide body vicinity. It is sectional drawing which shows another aspect of the discharge | release apparatus. It is sectional drawing which shows another aspect of the discharge | release apparatus.

DESCRIPTION OF SYMBOLS 100 Nanofiber manufacturing apparatus 101 Discharge apparatus 102 Guide body 103 Collecting apparatus 104 Attraction apparatus 105 Recovery apparatus 106 Packing 107 Supply apparatus 108 Storage chamber 109 Bearing 110 Outflow apparatus 111 Charging apparatus 112 Wind tunnel body 113 Second ventilation apparatus 114 Guide pipe 115 Outflow body 116 Shaft body 117 Driving device 118 Outflow hole 119 Rotating base body 120 Lid body 121 Charging electrode 122 Charging power source 123 Grounding device 124 Wind control body 125 Heating device 126 Diameter expansion portion 127 Diffuser 128 Deposited member 129 Winding device 130 Member supply device 131 Concentrating body 132 Suction device 133 Electric field attraction device 134 Attracting electrode 135 Attracting power source 137 Blower device 138 Blower unit 139 Compressor 141 Weight measuring device 142 Control device 143 Gas attraction device 144 Surface portion 145 Blower port 151 Container 1 2 a second container 153 booster 154 base plate 155 transfer device 156 discharging pipe 157 inlet pipe 158 gas introduction pipe 159 off valve 161 pressure source 162 control valve 169 nozzle 300 raw material liquid 301 nanofibers W1 layer flow W2 gas flow

Claims (7)

A nanofiber manufacturing apparatus for manufacturing nanofibers by electrically stretching a raw material liquid in a space,
An outflow body having an outflow hole for flowing the raw material liquid into the space;
A charging electrode disposed at a predetermined interval from the outflow body, the charging electrode having a convex curved surface portion on a surface facing the outflow body;
A blower that generates a laminar flow of gas directly above the surface portion;
A charging power source for applying a predetermined voltage between the effluent and the charging electrode ;
Wherein the laminar flow that occurs directly above the charging electrode, forcing device for production of nanofibres characterized in that the transport to another location come material solution and nano fibers approaching toward the charging electrode. The outflow body has a cylindrical shape,
The outflow hole is provided in a peripheral wall of the outflow body,
The charging electrode has an annular shape and is disposed so as to surround the effluent;
The nanofiber manufacturing apparatus according to claim 1, wherein the blower includes an annular blower opening along the charging electrode. further,
The nanofiber manufacturing apparatus according to claim 2, further comprising a driving device that rotates the outflow body. further,
The nanofiber manufacturing apparatus according to claim 1, further comprising a second air blowing device that generates a gas flow for transporting the nanofiber manufactured in the space. further,
The nanofiber manufacturing apparatus according to claim 1, further comprising a guide body that guides the nanofiber manufactured in the space to a predetermined place. further,
A collection device for collecting nanofibers produced in space;
The nanofiber manufacturing apparatus according to claim 1, further comprising an attracting device that attracts nanofibers to the collecting device. A nanofiber manufacturing method for manufacturing a nanofiber by electrically stretching a raw material liquid in a space,
An outflow step of flowing the raw material liquid into the space from the outflow hole of the outflow body;
A charging electrode disposed at a predetermined interval from the outflow body, the charging electrode having a convex curved surface portion on a surface facing the outflow body and a charging voltage for applying a predetermined voltage between the outflow body Process,
Look containing a blowing step of generating a laminar flow of gas immediately above the surface portion,
A nanofiber manufacturing method , wherein a raw material solution or a nanofiber approaching the charging electrode is forcibly conveyed to another place by a laminar flow generated immediately above the charging electrode .

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