JP4939478B2 - Nanofiber manufacturing method - Google Patents

Description

  The present invention relates to a nanofiber manufacturing method for manufacturing nanofibers using an electrospinning method (electrostatic explosion), and more particularly to a nanofiber manufacturing method in which the manufacturing method is changed based on the material of the manufactured nanofibers.

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

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

  More specifically, the volume of the raw material liquid that has been charged and flowed out decreases as the solvent evaporates from the raw material liquid in flight through the space. On the other hand, the charge imparted to the raw material liquid remains in the raw material liquid. As a result, the charge density of the raw material liquid in flight through the space increases. Since the solvent in the raw material liquid continues to evaporate, the charge density of the raw material liquid further increases, and the repulsive coulomb force generated in the raw material liquid becomes higher than the surface tension of the raw material liquid. A phenomenon (electrostatic explosion) occurs in which the molecular solution is stretched linearly. The electrostatic explosions occur one after another in the space, and nanofibers made of a polymer having a submicron diameter are manufactured.

The nanofibers manufactured in the space as described above are attracted to the deposition member by using an electric field because positive or negative charges remain (see, for example, Patent Document 1).
JP 2002-201559 A

  However, when nanofibers manufactured in a space are transported to a predetermined place by a gas flow, it has been found that it may be difficult to attract the nanofibers with an electric field. Furthermore, as a result of diligent research and experiments, we have found that there is a difference in the ability to maintain the charge depending on the type of polymer constituting the nanofiber.

  The present invention has been created based on the above knowledge, and an object thereof is to provide a nanofiber manufacturing method in which nanofibers are deposited and collected by a method corresponding to the properties of the nanofibers.

  In order to solve the above problems, a nanofiber manufacturing method according to the present invention includes a raw material liquid outflow step for flowing out a raw material liquid as a raw material for nanofibers into a space, and a raw material liquid charging step for charging the raw material liquid, When the nanofiber is transferred by the gas flow generated by the gas flow generation means, the charge state adjustment step for adjusting the charged state of the nanofiber being transferred, and the charge amount of the nanofiber increases due to the charge state adjustment step If the nanofiber is attracted to the deposition member for depositing the nanofiber by an electric field, and the charge amount of the nanofiber is reduced by the charging state adjustment process, the nanofiber is applied to the deposition member for depositing the nanofiber by a gas flow. An attracting step for attracting and a deposition step for receiving the nanofiber attracted by the attraction step and depositing the nanofiber on the deposition member. To.

  According to this, the nanofiber can be attracted to the deposition member by a method suitable for the material of the nanofiber, and the efficiency of depositing the nanofiber uniformly can be increased.

  In the case of a nanofiber made of a material that is easily charged, the charged state adjustment step increases the charge amount of the nanofiber by releasing ions or charged particles having the same polarity as the charged nanofiber into the space. In the case of a nanofiber made of a material that is difficult to be charged, the charged amount of the nanofiber is reduced by releasing ions or charged particles having a polarity opposite to that of the charged nanofiber into the space. It is preferable to adjust.

  According to this, in the case of a nanofiber made of a material that easily maintains charging, the nanofiber can be more easily attracted by an electric field by increasing the charge amount. On the other hand, in the case of a nanofiber made of a material that is difficult to maintain charge, by reducing the charge amount, repulsion between the nanofibers can be suppressed and the nanofiber can be more easily attracted by the gas flow.

  Furthermore, the charging process may include a compression process of compressing the nanofibers conveyed by the gas flow so that the spatial density of the nanofibers is increased, and the charged state adjusting step may adjust the charged state of the nanofibers in a compressed state.

  According to this, the nanofibers are present in a high density state in the space, and the charged state of the nanofibers can be easily adjusted.

  Furthermore, it includes a charge state detection step for detecting the charge state of the nanofibers conveyed by the gas flow. In the charge state adjustment step, if the detected charge state is less than the threshold value, the charge amount of the nanofiber is reduced. Adjustment may be made so that the charged amount of the nanofiber increases if the detected charged state is equal to or greater than the threshold value.

  According to this, even when manufacturing nanofibers made of a material whose properties are unknown, it is possible to manufacture nanofibers by an appropriate method.

  According to the present invention, when producing nanofibers made of a material whose charge amount is remarkably reduced during conveyance by a gas flow, the nanofibers are efficiently deposited by neutralizing the charge and attracting the nanofibers by the gas flow. Can be collected. On the other hand, when producing a nanofiber made of a material that can maintain the charge amount to some extent, it is possible to further enhance the charge and enhance the attraction of the nanofiber by an electric field.

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

  FIG. 1 is a cross-sectional view schematically showing a nanofiber manufacturing apparatus that can implement the present invention.

  As shown in FIG. 1, the nanofiber manufacturing apparatus 100 includes a discharge device 200 that manufactures nanofibers and discharges the manufactured nanofibers, and a collection device 110 that collects the nanofibers discharged from the discharge device 200. ing.

  The discharge device 200 includes a raw material liquid outflow means 201, a raw material liquid charging means 202, a guide means 206, and a gas flow generation means 203.

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

  The raw material liquid outflow means 201 is an apparatus that causes the raw material liquid 300 to flow out into the space. In this embodiment, an apparatus that discharges the raw material liquid 300 radially by centrifugal force is employed as the raw material liquid outflow means 201. As shown in FIG. 2 and FIG. 3, the raw material liquid outflow means 201 includes an outflow container 211, a rotating shaft body 212, and a motor 213.

  The outflow container 211 is a container capable of causing 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 has a cylindrical shape with one end closed. Has a number of outflow holes 216. The outflow container 211 is formed of a conductor in order to give a charge to the stored raw material liquid 300, and also functions as a component of the raw material liquid charging means 202. The outflow container 211 is rotatably supported by a bearing (not shown) provided on a support (not shown), and does not shake even when rotated at a high speed.

  Specifically, the diameter of the outflow container 211 is preferably adopted from a range of 10 mm to 300 mm. If it is too large, it will be difficult to concentrate the raw material liquid 300 and nanofiber 301 by the gas flow, and if the weight balance is slightly deviated, such as the rotation axis of the outflow vessel 211 is deviated, a large vibration will occur. This is because a structure that firmly supports the outflow container 211 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 motor load and vibration. Furthermore, it is preferable to employ the diameter of the outflow vessel 211 from the range of 20 mm or more and 100 mm or less. Further, the shape of the outflow hole 216 is preferably circular, and the diameter thereof is preferably adopted from the range of 0.01 mm to 3 mm.

  The shape of the outflow container 211 is not limited to a cylindrical shape, and may be a polygonal column shape having a polygonal side surface or a conical shape. It is only necessary that the raw material liquid 300 flows out of the outflow hole 216 by centrifugal force by rotating the outflow hole 216. Further, the shape of the outlet 216 is not limited to a circular shape, and may be a polygonal shape or a star shape.

  The rotating shaft body 212 is a shaft body for transmitting a driving force for rotating the outflow container 211 and causing the raw material liquid 300 to flow out by centrifugal force, and is inserted into the outflow container 211 from the other end of the outflow container 211. This is a rod-like body in which the closed portion and one end portion of the outflow container 211 are joined. The other end is joined to the rotating shaft of the motor 213. The rotating shaft body 212 includes an insulating portion (not shown) that is an insulating portion so that the outflow container 211 and a motor 213 described later are not electrically connected.

  The motor 213 is a device that applies a rotational driving force to the outflow container 211 via the rotary shaft body 212 in order to cause the raw material liquid 300 to flow out from the outflow hole 216 by centrifugal force. The rotational speed of the outflow vessel 211 is selected from a range of several rpm or more and 10,000 rpm or less depending on the diameter of the outflow hole 216, the viscosity of the raw material liquid 300 to be used, the type of polymer substance in the raw material liquid, and the like. Preferably, when the motor 213 and the outflow container 211 are in direct motion as in the present embodiment, the rotational speed of the motor 213 matches the rotational speed of the outflow container 211.

  The raw material liquid charging unit 202 is a device that charges the raw material liquid 300 by charging it. In the case of the present embodiment, the raw material liquid charging means 202 is a device that generates an induced charge and applies the charge to the raw material liquid 300, and includes an induction electrode 221, an induction power supply 222, and a grounding means 223. . The outflow container 211 also functions as part of the raw material liquid charging means 202.

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

  The size of the induction electrode 221 needs to be larger than the diameter of the outflow vessel 211, and it is preferable that the diameter is adopted from a range of 20 mm or more and 800 mm or less. The shape of the induction electrode 221 is not limited to an annular shape, and may be a polygonal annular member having a polygonal shape.

  The induction power supply 222 is a power supply that can apply a high voltage to the induction electrode 221. The induction power supply 222 is a DC power supply, and is a device that can set a voltage (referenced to the ground potential) applied to the induction electrode 221 and its polarity.

  The voltage applied by the induction power source 222 to the induction electrode 221 is preferably set from a value in the range of 10 KV to 200 KV. In particular, the electric field strength between the outflow vessel 211 and the induction electrode 221 is important, and it is preferable to arrange the applied voltage and the induction electrode 221 so that the electric field strength is 1 KV / cm or more. The shape of the induction electrode 221 is not limited to an annular shape, and may be a polygonal annular member having a polygonal shape.

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

  If the induction method is adopted for the raw material liquid charging means 202 as in the present embodiment, the raw material liquid 300 can be charged while the outflow vessel 211 is maintained at the ground potential. If the outflow vessel 211 is in the ground potential state, members such as the rotating shaft 212 and the motor 213 connected to the outflow vessel 211 do not need to take measures against the high voltage between the outflow vessel 211, and the raw material liquid A simple structure can be adopted as the outflow means 201, which is preferable.

  As the raw material liquid charging means 202, a charge may be applied to the raw material liquid 300 by connecting a power source directly to the outflow container 211, maintaining the outflow container 211 at a high voltage, and grounding the induction electrode 221. In addition, the outflow vessel 211 is formed of an insulator, and an electrode that directly contacts the raw material liquid 300 stored in the outflow vessel 211 is disposed inside the outflow vessel 211, and an electric charge is applied to the raw material liquid 300 using the electrode. It may be a thing.

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

  The gas flow generation means 203 includes a wind tunnel body 209 that is a conduit that guides the generated gas flow to the vicinity of the outflow vessel 211 without diverging. The gas flow guided by the wind tunnel body 209 intersects the raw material liquid 300 that has flowed out of the outflow vessel 211, and changes the flight direction of the raw material liquid 300.

  Furthermore, the gas flow generation unit 203 includes a gas flow control unit 204 and a heating unit 205.

  The gas flow control means 204 has a function of controlling the gas flow so that the gas flow generated by the gas flow generation means 203 does not hit the outflow hole 216. In this embodiment, as the gas flow control means 204, A wind tunnel body that guides the gas flow so as to flow to a predetermined region is employed. Since the gas flow does not directly hit the outflow hole 216 by the gas flow control means 204, the raw material liquid 300 flowing out from the outflow hole 216 is prevented from evaporating early and blocking the outflow hole 216 as much as possible. The liquid 300 can be kept flowing out stably. The gas flow control means 204 may be a wall-shaped windbreak wall that is arranged on the windward side of the outflow hole 216 and prevents the gas flow from reaching the vicinity of the outflow hole 216.

  The heating unit 205 is a heating source that heats the gas constituting the gas flow generated by the gas flow generation unit 203. In the case of the present embodiment, the heating means 205 is an annular heater disposed inside the wind tunnel body 209, and can heat the gas passing through the heating means 205. By heating the gas flow by the heating means 205, the raw material liquid 300 flowing out into the space is accelerated in evaporation, and nanofibers can be efficiently manufactured.

  Note that the gas flow generating means 203 may be constituted by another blower such as a sirocco fan. Further, the direction of the raw material liquid 300 that has flowed out by introducing high-pressure gas may be changed. Further, a gas flow may be generated inside the guiding means 206 by the second gas flow generating means 232 or the collecting device 110 described later. In this case, the nanofiber manufacturing apparatus 100 does not have a device that actively generates a gas flow. However, in the case of the present invention, the gas flow is generated when the gas flow is generated inside the wind tunnel body 209. It is assumed that the generation means 203 exists.

  The guiding means 206 is a conduit that forms a wind tunnel that guides the manufactured nanofiber 301 to the vicinity of the collecting device 110. The end of the guide means 206 is a tubular member that is connected to the end of the wind tunnel body 209 and can guide all of the nanofiber 301 produced from the raw material liquid outflow means 201 and the gas flow. In the case of the present embodiment, the compressing means 230 described later is also included in the guiding means 206 in the sense that the nanofiber 301 is guided.

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

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

  In addition, the end shape on the upstream side (introduction side) of the compression unit 230 is an annular shape that matches the end shape of the guide unit 206. On the other hand, the shape of the end portion on the downstream side (discharge side) of the compression means 230 is also annular.

  The second gas flow generation means 232 is a device that generates a gas flow by introducing a high-pressure gas into the compression conduit 234. In the present embodiment, the second gas flow generating means 232 employs an apparatus that includes a tank (cylinder) that can store high-pressure gas and a gas outlet means that includes a valve 235 that adjusts the pressure of the high-pressure gas in the tank. ing. A plurality of gas flow inlets 233 are provided on the peripheral wall of the compression conduit 234, and the second gas flow generating means 232 is connected to each of the gas flow inlets 233. In FIGS. Indicates only a part of the description and omits other descriptions.

  A charging state adjusting means 207 is attached to the inside of the compression conduit 234.

  The charged state adjusting means 207 is a device that has a function of enhancing the charging of the charged nanofiber 301, and also has a function of removing the charge of the charged nanofiber 301. As the charged state adjusting means 207, the ions and particles having the same polarity as the charged nanofibers 301 are released into the space to enhance the charging of the nanofibers 301, while the ions having the opposite polarity An apparatus capable of weakening the charging of the nanofiber 301 by discharging particles into the space can be listed. Specifically, there is a charging state adjusting means 207 comprising any method such as a corona discharge method, a voltage application method, an AC method, a steady DC method, a pulse DC method, a self-discharge method, a soft X-ray method, an ultraviolet ray method, and a radiation method. It can be illustrated.

  In addition, a charging state detection unit 114 is provided inside the guide unit 206, and a charging control unit 115 for controlling the charging state adjustment unit 207 based on a signal from the charging state detection unit 114 is provided.

  The charged state detection unit 114 is a device that measures the charged state of the nanofibers conveyed in the space by a gas flow as a potential, and is a device that transmits a measurement result to the charge control unit 115. The charged state detection means 114 is a device that can measure the so-called static state (potential) in a non-contact manner including the polarity, and the surface potential of the nanofiber 301 is not affected as much as possible by measuring the potential. It has become.

  The charging control unit 115 controls the charging state adjustment unit 207 so that the charging amount of the nanofiber 301 is reduced if the absolute value of the charging potential of the nanofiber 301 detected by the charging state detection unit 114 is less than the threshold value. If the absolute value of the charged potential of the nanofiber 301 detected by the charged state detecting means 114 is equal to or greater than the threshold value, the processing apparatus controls the charged state adjusting means 207 so that the charged amount of the nanofiber 301 increases. The charging control means 115 is realized by a computer and a program.

  The nanofiber manufacturing apparatus 100 includes a first collection device 110 that attracts the nanofiber 301 with an electric field, and a second collection device 110 that attracts the nanofiber 301 with a gas flow.

  As shown in FIGS. 1 and 4, the first collection device 110 includes a deposition member 101, a supply unit 111, a collection unit 104, an attracting electrode 112 as an attracting unit, and an attracting power source 113 as an attracting unit. The base 117 is provided.

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

  The supply means 111 is a device that can sequentially supply the deposition member 101 wound around the winding member, and is provided with a tensioner so that the deposition member 101 can be supplied with a predetermined tension.

  The collecting unit 104 is an apparatus that pulls out the long deposition member 101 from the supply unit 111 while winding it, and collects the deposition member 101 together with the nanofibers 301 to be deposited. The collecting means 104 is capable of winding the nanofiber 301 deposited in a nonwoven fabric shape together with the deposition member 101.

  The attracting electrode 112 is a conductor member that is maintained at a predetermined potential with respect to the ground by the attracting power source 113. When a potential is applied to the attracting electrode 112, an electric field is generated in the space. The attracting electrode 112 is a rectangular plate-shaped member, has no protruding portion for preventing discharge, and all corners are rounded.

  The attraction power source 113 is a DC power source capable of maintaining the attraction electrode 112 at a predetermined potential with respect to the ground. Further, the attracting power source 113 can change the positive / negative (including the ground potential) of the potential applied to the attracting electrode 112.

  The base 117 is a member attached so that the deposition member 101, the supply unit 111, the recovery unit 104, the attracting electrode 112, and the attracting power source 113 are integrated. In the case of the present embodiment, the base 117 is a box-shaped member that can accommodate the deposition member 101, the supply unit 111, the recovery unit 104, the attracting electrode 112, and the attracting power source 113 inside.

  In addition, a diffusion means 240 is attached to the inside of the base body 117, and a wheel 118 is provided below the base body 117.

  The diffusing means 240 is a conduit that diffuses and disperses the nanofibers 301 that have been compressed at one end by the compressing means 230 and diffuses widely, and is a hood-like member that reduces the speed of the nanofibers 301 accelerated by the compressing means 230 It is. The diffusing means 240 includes an upstream end side opening into which the gas flow is introduced and a downstream end rectangular opening that discharges the gas flow, and the opening area of the downstream end side opening is the upstream end side. It is set to be larger than the opening area of the opening. The diffusing means 240 has a shape that gradually increases in area from the opening on the upstream end side toward the opening on the downstream end side. The opening on the downstream end side has a width substantially equal to the width of the deposition member 101 and has a shape longer than the attracting electrode 112.

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

  Note that the diffusing means 240 may be provided not on the collection device 110 but on the discharge device 200 side.

  The wheel 118 is a wheel provided to make the first collection device 110 movable, and is rotatably attached to the lower portion of the base body 117. In the case of the present embodiment, the wheel 118 rotates on the rail.

  As shown in FIGS. 5 and 6, the second collection device 110 includes a deposition member 101, a supply unit 111, a recovery unit 104, a suction unit 102 as an attraction unit, and a base body 117.

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

  Further, the deposition member 101 includes a large number of ventilation holes (not shown) for ensuring the air permeability of the gas flow generated by the gas flow generation means 203, and the nanofiber 301 is deposited but the gas flow passes therethrough. This is a mesh filter.

  The supply means 111 is a device that can sequentially supply the deposition member 101 wound around the winding member, and is provided with a tensioner so that the deposition member 101 can be supplied with a predetermined tension.

  The collecting unit 104 is an apparatus that pulls out the long deposition member 101 from the supply unit 111 while winding it, and collects the deposition member 101 together with the nanofibers 301 to be deposited. The collecting means 104 is capable of winding the nanofiber 301 deposited in a nonwoven fabric shape together with the deposition member 101.

  The suction means 102 is a device that forcibly sucks the gas flow passing through the deposition member 101 together with the solvent evaporated from the raw material liquid 300. In the present embodiment, a blower such as a sirocco fan or an axial fan is employed as the suction unit 102. Further, the suction unit 102 can suck most of the gas stream mixed with the solvent evaporated from the raw material liquid 300 and can transport the gas stream to the solvent recovery device 106 connected to the suction unit 102. Yes.

  The region regulating unit 103 includes an opening having the same shape and the same area as the lead-out opening end of the diffusing unit 240 on the deposition member 101 side, and the opening on the side connected to the suction unit 102 corresponds to the suction unit 102. It is circular. Thus, the entire nanofiber 301 diffused by the diffusing means 240 is attracted onto the deposition member 101 and all the gas flow is sucked.

  The base 117 is a member attached so that the deposition member 101, the supply unit 111, the recovery unit 104, and the suction unit 102 are integrated. In the case of the present embodiment, the base body 117 is a box-shaped member that can accommodate the deposition member 101, the supply unit 111, and the recovery unit 104 inside.

  In addition, a diffusion means 240 is attached to the inside of the base body 117, and a wheel 118 is provided below the base body 117.

  The diffusing means 240 is a conduit that diffuses and disperses the nanofibers 301 that have been compressed at one end by the compressing means 230 and diffuses widely, and is a hood-like member that reduces the speed of the nanofibers 301 accelerated by the compressing means 230 It is. The diffusing means 240 includes an upstream end side opening into which the gas flow is introduced and a downstream end rectangular opening that discharges the gas flow, and the opening area of the downstream end side opening is the upstream end side. It is set to be larger than the opening area of the opening. The diffusing means 240 has a shape that gradually increases in area from the opening on the upstream end side toward the opening on the downstream end side. The opening on the downstream end side has a width substantially equal to the width of the deposition member 101.

  When the gas flow flows from the small area introduction end side of the diffusing means 240 toward the large area lead-out end side, the nanofibers 301 in a high density state are dispersed in a low density state at once, and the flow velocity of the gas flow is It falls in proportion to the cross-sectional area of the diffusing means 240. Therefore, the speed of the nanofiber 301 carried on the gas flow is reduced along with the gas flow. At this time, the nanofiber 301 gradually and uniformly diffuses as the cross-sectional area of the diffusing means 240 increases. Therefore, the nanofibers 301 can be uniformly deposited on the deposition member 101. Further, nanofibers collected by the suction means 102 are deposited on the surface of the deposition member 101.

  The wheel 118 is a wheel provided to make the first collection device 110 movable, and is rotatably attached to the lower portion of the base body 117. In the case of the present embodiment, the wheel 118 rotates on the rail.

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

  A nanofiber 301 made of a predetermined material is manufactured. Here, if the nanofiber 301 is capable of maintaining charging during transportation, the first collection device 110 is attached to the nanofiber manufacturing apparatus 100, and if the nanofiber 301 is difficult to maintain charging during transportation, the nanofiber 301 is nanoscopic. The second collection device 110 is attached to the fiber manufacturing apparatus 100.

  A gas flow is generated inside the guide unit 206 and the wind tunnel body 209 by the gas flow generation unit 203 and the second gas flow generation unit 232.

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

  The polymer substance constituting the nanofiber 301 includes polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, polyfluoride. Vinylidene 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 , Polypeptides and the like and can be exemplified by a copolymer thereof. 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.

  Further, as a polymer substance that is difficult to maintain charging, a case where a polymer type antistatic material is added can be exemplified. Examples of the polymer type antistatic material include ENTILA (registered trademark, manufactured by Mitsui DuPont Polychemical Co., Ltd.). In addition, polymer materials that are difficult to maintain charge include inorganic polymers (with silicon as a skeleton), natural polymers (silicon dioxide (quartz, quartz), mica, feldspar, asbestos), synthetic polymers (silicone resin) (Silicone rubber, silicone oil), glass, synthetic ruby) can also be exemplified.

  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 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 about 60% to 98%.

  Next, while supplying electric charge to the raw material liquid 300 stored in the outflow container 211 by the induction power source 222 (raw material liquid charging step), the outflow container 211 is rotated by the motor 213 and charged from the outflow hole 216 by centrifugal force. The raw material liquid 300 flows out (raw material liquid outflow process).

  The raw material liquid 300 that has flowed radially out of the outflow vessel 211 is changed in flight direction by the gas flow and is guided by the wind tunnel body 209 in the gas flow. The raw material liquid 300 is discharged to the guide means 206 while manufacturing the nanofiber 301 by the electrostatic explosion (nanofiber manufacturing process). The gas flow is heated by the heating means 205, and heats the raw material liquid 300 to promote the evaporation of the solvent while guiding the flight of the raw material liquid 300. As described above, the nanofiber 301 is conveyed by the gas flow inside the guide unit 206 (conveying step).

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

  Here, the charged potential of the nanofiber 301 conveyed by the gas flow is detected by the charged state detecting means 114 (charged state detecting step).

  If the absolute value of the charging potential of the nanofiber 301 detected by the charging state detection unit 114 is less than the threshold value, the charging control unit 115 adjusts the charging state so that the charging amount of the nanofiber 301 is 0, that is, completely neutralized. The means 207 is controlled (charging state adjustment step). In this case, a second collection device 110 that attracts the nanofibers 301 with a gas flow is used.

  On the other hand, if the absolute value of the charging potential of the nanofiber 301 detected by the charging state detection unit 114 is equal to or greater than the threshold value, the charging state adjustment unit 207 is controlled so that the charging potential of the nanofiber 301 becomes a predetermined potential. (Charge state adjustment process). In this case, the 1st collection apparatus 110 which attracts the nanofiber 301 with an electric field is used.

  In addition, when the tendency of the charged state of the nanofiber 301 can be grasped in advance based on the state of the raw material liquid 300 (such as the type of solvent and the type of polymer substance), the first collection device 110 is based on the raw material liquid 300. Alternatively, it may be switched to the second collection device 110 (switching step).

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

  In this state, when the second collection device 110 is attached to the nanofiber manufacturing apparatus 100, the nanofiber 301 is attracted by the gas flow sucked by the suction means 102 (attraction process). Since the gas flow is sucked through the deposition member 101, the nanofibers 301 are deposited on the deposition member 101 (deposition step).

  On the other hand, when the first collection device 110 is attached to the nanofiber manufacturing device 100, the attracting electrode 112 disposed in the opening of the diffusing means 240 is charged with a polarity opposite to the charged polarity of the nanofiber 301. The nanofiber 301 is attracted (attraction process). Since the deposition member 101 exists between the nanofiber 301 and the attracting electrode 112, the nanofiber 301 attracted to the attracting electrode 112 is deposited on the deposition member 101 (deposition step).

  In the above method, if the nanofiber 301 can maintain the charge during transportation, the charged state can be adjusted after detecting the potential of the nanofiber 301 being transported, so that the charged potential of the nanofiber 301 is kept constant. be able to. As a result, the nanofiber 301 can be stably attracted by the electric field, and the nanofiber 301 can be evenly deposited on the deposition member 101. Furthermore, if the charged potential to be maintained is maintained at a high level, it is possible to efficiently deposit on the deposition member 101 and deposit the nanofiber 301 in a thick state.

  On the other hand, in the case of the nanofiber 301 that is difficult to maintain the charge during the conveyance, the nanofiber 301 is neutralized during the conveyance, so that when the nanofiber 301 is attracted with the gas flow, It is possible to attract the nanofibers 301 evenly on the deposition member 101 while suppressing the disturbance of the spatial density of the fibers 301.

  The arrangement of the charged state adjusting unit 207 and the charged state detecting unit 114 is not limited to this, and may be arranged at any location where the step before the nanofiber is deposited on the deposition member 101 is realized. Good.

  In the embodiment of the present application, the first collection device and the second collection device are built in separate substrates 117, but as shown in FIG. 7, the nanofiber 301 is attracted by an electric field. Means and means for attracting nanofibers 301 with a gas flow may coexist in a single collection device. That is, the attracting electrode 112, the attracting power source 113, and the suction means 102 are arranged in the same collecting device, and the nanofibers are applied in the electric field based on the detection status of the charged state detection means 114 depending on the status of the raw material liquid or polymer substance used Switching between means for attracting 301 and means for attracting the nanofiber 301 with a gas flow may be performed (switching step). Specifically, if the absolute value of the charging potential of the nanofiber 301 detected by the charging state detection unit 114 is less than the threshold value, the suction unit 102 is controlled so as to attract the nanofiber 301 by a gas flow, thereby detecting the charging state. If the absolute value of the charging potential of the nanofiber 301 detected by the means 114 is equal to or greater than the threshold, the attracting power source may be controlled so as to attract the nanofiber 301 with an electric field. In this case, as shown in FIG. 8, if the attracting electrode 112 has a shape in which the gas flow can be vented, switching between the attraction by the electric field and the attraction by the gas flow can be easily performed. By adopting this method, it may be possible to deposit the nanofibers 301 smoothly.

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

It is sectional drawing which shows typically the state to which the discharge | release apparatus and the 1st collection apparatus were attached. It is sectional drawing which shows the outflow apparatus vicinity. It is a perspective view which shows the outflow apparatus vicinity. It is a perspective view which abbreviate | omits a part of base | substrate and shows a 1st collection apparatus. It is sectional drawing which shows typically the state to which the discharge | release apparatus and the 2nd collection apparatus were attached. It is a perspective view which abbreviate | omits a part of base | substrate and shows a 2nd collection apparatus. It is sectional drawing which shows typically the nanofiber manufacturing apparatus which concerns on other embodiment. It is a perspective view which shows an attracting electrode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Nanofiber manufacturing apparatus 101 Deposition member 102 Suction means 103 Area | region control means 104 Recovery means 106 Solvent recovery apparatus 110 Collection apparatus 111 Supply means 112 Attracting electrode 113 Attracting power supply 114 Charge state detection means 115 Charging control means 117 Base 118 Wheel 200 Ejection apparatus 201 Raw material liquid outflow means 202 Raw material liquid charging means 203 Gas flow generation means 204 Gas flow control means 205 Heating means 206 Guide means 207 Charged state adjustment means 209 Wind tunnel body 211 Outflow container 212 Rotating shaft body 213 Motor 216 Outflow hole 217 Supply path 221 Induction electrode 222 Induction power source 223 Grounding means 230 Compression means 232 Second gas flow generation means 233 Gas flow inlet 234 Compression conduit 235 Valve 240 Diffusion means 300 Raw material liquid 301 Nanofiber

Claims (5)

A raw material liquid outflow process for flowing out the raw material liquid that is the raw material of the nanofiber into the space,
A raw material liquid charging step for charging the raw material liquid;
A transporting process for transporting nanofibers by a gas flow generated by the gas flow generating means;
In the case of nanofibers made of materials that are easily charged, the charge of the nanofibers is adjusted and increased by releasing ions and charged particles of the same polarity as the charged nanofibers into the space. In the case of nanofibers made of difficult materials, the charged nanofibers are being transported so that the charged amount of the nanofibers is reduced by releasing ions or charged particles of opposite polarity to the charged nanofibers into the space. A charge state adjustment step for adjusting the state;
When the charge amount of the nanofiber is increased by the charge state adjustment process, the nanofiber is attracted to the deposition member for depositing the nanofiber by an electric field, and when the charge amount of the nanofiber is decreased by the charge state adjustment process, An attracting step for attracting the nanofibers to the deposition member for depositing the nanofibers by a gas flow;
A deposition step of receiving the nanofibers attracted by the attraction step and depositing the nanofibers on the deposition member;
A nanofiber manufacturing method comprising: A raw material liquid outflow process for flowing out the raw material liquid that is the raw material of the nanofiber into the space,
A raw material liquid charging step for charging the raw material liquid;
A transporting process for transporting nanofibers by a gas flow generated by the gas flow generating means;
A compression stroke that compresses as the spatial density of nanofibers increases carried in the gas flow,
A charge state adjustment step for adjusting the charge state of the nanofiber in a compressed state;
When the charge amount of the nanofiber is increased by the charge state adjustment process, the nanofiber is attracted to the deposition member for depositing the nanofiber by an electric field, and when the charge amount of the nanofiber is decreased by the charge state adjustment process, An attracting step for attracting the nanofibers to the deposition member for depositing the nanofibers by a gas flow;
A deposition step of receiving the nanofibers attracted by the attraction step and depositing the nanofibers on the deposition member;
A nanofiber manufacturing method comprising: A raw material liquid outflow process for flowing out the raw material liquid that is the raw material of the nanofiber into the space,
A raw material liquid charging step for charging the raw material liquid;
A transporting process for transporting nanofibers by a gas flow generated by the gas flow generating means;
A charging state detecting step of detecting a charged state of nanofibres carried in the gas flow,
If the detected charge state is less than the threshold, the charge state of the nanofiber being conveyed is adjusted so that the charge amount of the nanofiber is reduced. If the detected charge state is equal to or greater than the threshold value, the charge amount of the nanofiber is adjusted. A charging state adjustment step of adjusting the charging state of the nanofiber being conveyed so that the
When the charge amount of the nanofiber is increased by the charge state adjustment process, the nanofiber is attracted to the deposition member for depositing the nanofiber by an electric field, and when the charge amount of the nanofiber is decreased by the charge state adjustment process, An attracting step for attracting the nanofibers to the deposition member for depositing the nanofibers by a gas flow;
A deposition step of receiving the nanofibers attracted by the attraction step and depositing the nanofibers on the deposition member;
A nanofiber manufacturing method comprising: A raw material liquid outflow process for flowing out the raw material liquid that is the raw material of the nanofiber into the space,
A raw material liquid charging step for charging the raw material liquid;
A transporting process for transporting nanofibers by a gas flow generated by the gas flow generating means;
A charging state adjustment step for adjusting the charging state of the nanofiber being conveyed;
When the charge amount of the nanofiber is increased by the charge state adjustment process, the nanofiber is attracted to the deposition member for depositing the nanofiber by an electric field, and when the charge amount of the nanofiber is decreased by the charge state adjustment process, An attracting step for attracting the nanofibers to the deposition member for depositing the nanofibers by a gas flow;
A switching step of switching between a collecting device for attracting nanofibers by an electric field and a collecting device for attracting nanofibers by a gas flow based on the type of the raw material liquid ,
A deposition step of receiving the nanofibers attracted by the attraction step and depositing the nanofibers on the deposition member;
A nanofiber manufacturing method comprising: A raw material liquid outflow process for flowing out the raw material liquid that is the raw material of the nanofiber into the space,
A raw material liquid charging step for charging the raw material liquid;
A transporting process for transporting nanofibers by a gas flow generated by the gas flow generating means;
A charging state adjustment step for adjusting the charging state of the nanofiber being conveyed;
When the charge amount of the nanofiber is increased by the charge state adjustment process, the nanofiber is attracted to the deposition member for depositing the nanofiber by an electric field, and when the charge amount of the nanofiber is decreased by the charge state adjustment process, An attracting step for attracting the nanofibers to the deposition member for depositing the nanofibers by a gas flow;
A switching step of switching between a collecting device for attracting nanofibers by an electric field and a collecting device for attracting nanofibers by a gas flow based on the charging state of the nanofibers detected by the charged state adjusting step ,
A deposition step of receiving the nanofibers attracted by the attraction step and depositing the nanofibers on the deposition member;
A nanofiber manufacturing method comprising:

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