JP4892508B2 - Nanofiber manufacturing method and nanofiber manufacturing apparatus - 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 for collecting nanofibers in a state where predetermined performance can be exhibited.

  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 ejected (discharged) into the space by a nozzle or the like, and the raw material liquid is charged and charged to fly through the space. This is a method for obtaining nanofibers by electrostatically exploding the raw material liquid therein.

  More specifically, the volume of the raw material liquid is reduced as the solvent evaporates from the particles of 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 particles of the raw material liquid flying in the space increases. Since the solvent in the raw material liquid continues to evaporate, the charge density of the raw material liquid grains further increases, and the coulomb force in the repulsive direction generated in the raw material liquid grains exceeds the surface tension of the raw material liquid. When this occurs, a phenomenon (electrostatic explosion) occurs in which the polymer solution is stretched linearly explosively. The electrostatic explosions occur one after another in the space, and nanofibers made of a polymer having a submicron diameter are manufactured.

Here, when using the nanofiber manufactured by the said electrospinning method as a raw material of a filter, it is necessary for the collected nanofiber to exhibit predetermined performance. Therefore, in the invention described in Patent Document 1, the thickness of nanofibers collected using a laser-type non-contact thickness meter is measured, and the injection amount of the raw material liquid injected from the nozzle based on the measurement result is It is controlled.
JP 2007-92237 A

  However, simply measuring the thickness of the collected nanofibers only gives an analogy of the performance as a filter when applying the collected nanofibers to a filter, etc., and it is unclear whether sufficient performance has been obtained. is there.

  Therefore, the inventors transported the manufactured nanofibers separately invented by a gas flow, came up with a deposition means, and as a result of earnest research, as a result of earnest research, the nanofibers deposited during the manufacturing process I found that performance can be measured.

  That is, the present invention measures the performance of deposited nanofibers during the production of nanofibers, and stably produces a collection of nanofibers that can achieve the desired performance using the results. The purpose is to do.

  In order to achieve the above object, a nanofiber manufacturing apparatus according to the present invention comprises: an injection unit that injects a raw material liquid that is a raw material of nanofibers into a space; and a charging unit that imparts a charge to the raw material liquid and charges it. A gas flow generating means for generating a gas flow for guiding the nanofibers, a sheet-like deposition means capable of depositing the nanofibers and allowing the gas flow to be inserted therein, and a nano deposited by moving the deposition means. Conveying means for conveying the fiber, guiding means for forming a wind tunnel for guiding the manufactured nanofibers to the deposition means, and suction for disposing the gas flow disposed on the opposite side of the guiding means with respect to the deposition means Means, area regulating means for regulating the suction area of the suction means, first pressure measuring means for measuring the pressure of the gas flow inside the guiding means, and gas inside the area regulating means Second pressure measuring means for measuring the pressure of the first, and manufacturing condition control for controlling the nanofiber manufacturing conditions based on the difference between the first measurement result of the first pressure measuring means and the second measurement result of the second pressure measuring means Means.

  Thereby, the passage amount of the gas flow of the deposited nanofiber can be read as a pressure difference before and after passing through the nanofiber on which the gas flow is deposited even during the production of the nanofiber. Therefore, since the nanofiber production conditions can be adjusted after accurately grasping the performance of the deposited nanofiber, it is possible to stably produce a nanofiber deposit exhibiting a predetermined performance. .

  The manufacturing condition control unit preferably includes a conveyance control unit that controls the conveyance unit.

  Thereby, it becomes possible to adjust the performance of the nanofiber deposited easily and effectively.

  In order to achieve the above object, a nanofiber manufacturing method according to the present invention includes an injection unit that injects a raw material liquid that is a raw material of nanofibers into a space, and a charging that charges the raw material liquid by charging it. Means, a gas flow generating means for generating a gas flow for guiding the nanofibers, a sheet-like deposition means capable of depositing the nanofibers and allowing the gas flow to pass therethrough, and depositing by moving the deposition means A conveying means for conveying the nanofibers, a guiding means for forming a wind tunnel for guiding the manufactured nanofibers to the deposition means, and a gas flow that is disposed opposite to the guiding means with respect to the deposition means. Suction means, area restriction means for restricting the suction area of the suction means, first pressure measurement means for measuring the pressure of the gas flow inside the guide means, and inside the area restriction means A nanofiber manufacturing method using a nanofiber manufacturing apparatus comprising a second pressure measuring means for measuring a pressure of a gas flow, wherein the first measurement result of the first pressure measuring means and the second pressure measuring means The method includes a pressure difference calculating step of calculating a difference from the second measurement result as a pressure difference, and a manufacturing condition control step of controlling nanofiber manufacturing conditions based on the calculated pressure difference.

  Thereby, the passage amount of the gas flow of the deposited nanofiber can be read as a pressure difference before and after passing through the nanofiber on which the gas flow is deposited even during the production of the nanofiber. Therefore, since the nanofiber production conditions can be adjusted after accurately grasping the performance of the deposited nanofiber, it is possible to stably produce a nanofiber deposit exhibiting a predetermined performance. .

  Preferably, the manufacturing condition control step includes a transport control step for controlling a transport amount of the deposited nanofibers.

  Thereby, it becomes possible to adjust the performance of the nanofiber deposited easily and effectively.

  Further, the transport control step increases the transport amount so that the pressure difference does not become higher than a predetermined set upper limit value, and decreases the transport amount so that the pressure difference does not become lower than a predetermined lower limit value. It is preferable to control the conveying means.

  According to this, it becomes possible to collect the nanofibers having a predetermined performance in a long state by finely controlling the transport amount.

  Further, the transport control step transports a predetermined amount when the pressure difference becomes higher than a predetermined set upper limit value, and does not perform transport while the pressure difference is lower than the set upper limit value. Is preferably controlled.

  According to this, it is easy to control and it is possible to collect a large number of nanofibers having a predetermined performance in a short state.

  The manufacturing condition control step preferably includes an injection control step for controlling the injection amount of the raw material liquid in the injection means.

  Thereby, it is possible to perform deposition while adjusting not only the performance in the deposition direction of the nanofibers to be deposited but also the performance in the surface direction to be deposited.

  The manufacturing condition control step preferably includes a flow rate control step for controlling a flow rate of the gas flow in the gas flow generation means.

  According to this, it becomes possible to collect nanofibers while adjusting the entanglement (texture) of the deposited nanofibers.

  The manufacturing condition control step preferably includes an injection control step of controlling the number of revolutions of the injection container when the injection means is an injection means for rotating the injection container to inject from the small hole.

  According to this, the amount of manufactured nanofibers is controlled, and it is possible to collect the nanofibers uniformly in the plane direction.

  According to the present invention, the manufacturing conditions can be adjusted while accurately grasping the performance of the deposited nanofiber, and therefore, a nanofiber deposit having a desired performance can be manufactured accurately and stably. Is possible.

  Next, an embodiment according to the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view schematically showing a nanofiber manufacturing apparatus according to an embodiment of the present invention.

  As shown in the figure, the nanofiber manufacturing apparatus 100 includes an ejection unit 201, a charging unit 202, a guide unit 206, a gas flow generation unit 203, a deposition unit 101, a transport unit 104, and a suction unit 102. The region regulating means 103, the first pressure measuring means 241, the second pressure measuring means 107, and the manufacturing condition control means 302 are provided.

  The injection means 201 is an apparatus that injects the raw material liquid 300 into the space, as shown in FIG. 2 and FIG. 2 and FIG. 3, and in the present embodiment, is an apparatus that injects the raw material liquid 300 radially by centrifugal force. is there. The injection unit 201 includes an injection container 211, a rotating shaft body 212, and a motor 213.

  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 injection container 211 is a container that can inject the raw material liquid 300 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 injection ports 216. The injection container 211 is formed of a conductor in order to give a charge to the stored raw material liquid 300. The injection container 211 is rotatably supported by a bearing (not shown) provided on a support (not shown).

  Specifically, it is preferable that the diameter of the ejection container 211 is adopted from a range of 10 mm to 200 mm. It is because it will become difficult to concentrate the raw material liquid 300 and the nanofiber 301 by a gas flow if too large. On the other hand, if it is too small, the rotation for injecting the raw material liquid 300 by centrifugal force must be increased, and problems such as motor load and vibration occur. Furthermore, it is preferable to employ the diameter of the injection container 211 from the range of 20 mm or more and 80 mm or less. Moreover, the shape of the injection port 216 is preferably circular, and the diameter is preferably employed from a range of 0.01 mm to 2 mm.

  The rotation shaft body 212 is a shaft body for transmitting a driving force for rotating the injection container 211 and injecting the raw material liquid 300 by centrifugal force, and is inserted into the injection container 211 from the other end of the injection container 211. This is a rod-like body in which the closing portion and one end portion of the injection container 211 are joined. The other end is joined to the rotating shaft of the motor 213.

  The motor 213 is a device that applies a rotational driving force to the injection container 211 via the rotary shaft body 212 in order to inject the raw material liquid 300 from the injection port 216 by centrifugal force. The number of revolutions of the injection container 211 is selected from a range of several rpm or more and 10,000 rpm or less depending on the diameter of the injection port 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. It is preferable that when the motor 213 and the ejection container 211 are linearly moved as in the present embodiment, the rotational speed of the motor 213 matches the rotational speed of the ejection container 211.

  The charging means 202 is a device for applying a charge to the raw material liquid 300 and charging it as shown in FIG. In the present embodiment, the charging unit 202 includes an induction electrode 221, an induction power source 222, and a ground unit 223. In addition, the ejection container 211 also functions as a part of the charging unit 202.

  The induction electrode 221 is a member for inducing electric charge to the injection container 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 injection container 211. It is an annular member. The induction electrode 221 also functions as a guide unit 206 that guides the gas flow from the gas flow generation unit 203 and guides the nanofiber 301.

  The size of the induction electrode 221 needs to be larger than the diameter of the ejection container 211, and the diameter is preferably adopted from a range of 200 mm or more and 800 mm or less.

  The induction power supply 222 is a power supply that can apply a high voltage to the induction electrode 221. In general, the induction power supply 222 is preferably a DC power supply. In particular, a direct-current power supply is preferable when the charged polarity of the nanofiber 301 to be generated is not affected, or when the charged nanofiber 301 is collected and collected on the electrode. In other cases, an AC power source may be used. In addition, when the induction power supply 222 is a DC power supply, the voltage applied by the induction power supply 222 to the induction electrode 221 is preferably set from a value in the range of 10 KV or more and 200 KV or less. In particular, the electric field strength is important, and it is preferable to arrange the applied voltage and the induction electrode so that the electric field strength is 1 KV / cm or more.

  The grounding means 223 is a member that is electrically connected to the ejection container 211 and can maintain the ejection container 211 at a 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 injection container 211 is in a rotating state, and the other end is connected to the ground.

  If an induction method is employed for the charging means 202 as in the present embodiment, it is possible to apply a charge to the raw material liquid 300 while maintaining the injection container 211 at the ground potential. If the injection container 211 is in a ground potential state, it is not necessary to electrically insulate members such as the rotary shaft 212 and the motor 213 connected to the injection container 211 from the injection container 211, and the structure of the injection unit 201 is simple. Can be adopted, which is preferable.

  In addition, as the charging unit 202, a power source may be connected to the injection container 211, and the injection container 211 may be maintained at a high voltage to apply charge to the raw material liquid 300. In addition, the injection container 211 is formed of an insulator, and an electrode that is in direct contact with the raw material liquid 300 stored in the injection container 211 is disposed inside the injection container 211, and an electric charge is applied to the raw material liquid 300 using the electrode. It may be a thing.

  The guide unit 206 guides the gas flow to the deposition unit 101 through a predetermined flow path, and forms a wind tunnel having a function of guiding the nanofiber 301 manufactured by being mounted on the gas flow to the deposition unit 101. It is a member. In the case of the present embodiment, the guide unit 206 includes a changing unit 260, a merging unit 261, a static eliminating unit 264, and an accelerating unit 265.

  The change unit 260 is a part of the guide unit 206 having a function of changing the flight direction of the raw material liquid 300 injected from the injection unit 201 by the gas flow to be guided. The induction electrode 221 also belongs to the change unit 260. The change unit 260 is a cylindrical body having a frustoconical outer shape with the gas flow generating unit 203 connected to the opening at the end, and the injection unit 201 is disposed inside the change unit 260.

  The joining part 261 is a part of the guiding means 206 having a function of bringing together the raw material liquid 300 injected at a plurality of locations and the manufactured nanofibers 301 together with the guiding gas flow. The merge part 261 is formed of a relatively small cylinder connected to the changing part 260 and a relatively large cylinder in which the cylinders are assembled. In the case of the present embodiment, since there are two changing portions 260 corresponding to the injection means 201, two small cylinders and one large cylinder form a Y-shaped flow path. It has become.

  The static elimination unit 264 is a part having a function of removing the charge of the manufactured nanofiber 301, and is a part of the guide unit 206 connected subsequent to the junction part 261. The means for neutralizing the nanofiber 301 may be a long static elimination section 264 that neutralizes the static electricity by elongating the flow path that guides the nanofiber 301, and positively using the neutralization means 207 to actively remove the nanofiber. It is also possible to remove the charge 301.

  The neutralization unit 207 is a device that neutralizes the charged nanofiber 301. The neutralization means 207 can list an apparatus that can discharge ions or particles having a polarity opposite to that of the charged nanofiber 301 into the space, for example. Specifically, the static elimination means 207 which employs 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 is adopted. Good. Further, the static elimination means 207 needs to neutralize the nanofiber 301 after the electrostatic explosion is completed.

  The acceleration unit 265 is a part of the guide unit 206 that increases the flight speed of the nanofiber 301 that is merged at the merge unit 261 and is neutralized by the neutralization unit 264, and the second gas flow generation unit 232 via the gas flow introduction port 233. Is connected. The acceleration part 265 is a cylindrical member connected to the static elimination part 264, and can introduce the gas flow generated by the second gas flow generation means 232 inward through the gas flow inlet 233. It has become. The acceleration part 265 has a funnel shape as a whole, compresses the nanofiber 301 introduced into the acceleration part 265 together with the gas flow, and increases the pressure toward the outlet part.

  Note that the upstream end portion (introduction side) end shape of the acceleration unit 265 is an annular shape that matches the end shape of the static elimination means 207. On the other hand, the downstream end (discharge side) end shape of the acceleration unit 265 is a rectangle. Further, the downstream end (discharge side) end shape of the accelerating portion 265 extends over the entire width direction (perpendicular to the paper surface of the drawing) of the deposition unit 101, and the movement direction of the deposition unit 101 is relative to the width direction. Narrow. The shape of the acceleration part 265 gradually changes from the annular upstream end toward the rectangular downstream end.

  The second gas flow generating means 232 is a device that generates a gas flow by introducing a high-pressure gas into the acceleration unit 265. 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.

  The gas supplied by the second gas flow generating means 232 may be air, but is preferably a safety gas having an oxygen content ratio lower than that of air. This is to avoid explosion caused by the solvent evaporating from the raw material liquid 300. As the safety gas, a low oxygen concentration gas obtained by removing oxygen to some extent from air by a resin membrane (hollow fiber membrane) and superheated steam can be listed. This description does not exclude the use of high-purity gas containing almost no oxygen, but carbon dioxide supplied from high-purity nitrogen or dry ice sealed in a cylinder in a liquid or gas state. Etc. are also available.

  Further, a heating means for heating the gas flow generated by the second gas flow generation means 232 may be provided.

  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 injected from the injection container 211 to a direction along the axis of the guide unit 206. The gas flow generation unit 203 is attached to the end of the guide unit 206 and generates a gas flow from the change unit 260 toward the acceleration unit 265. The gas flow generation means 203 can generate wind power that can change the raw material liquid 300 in the axial direction until the raw material liquid 300 injected in the radial direction from the injection container 211 reaches the induction electrode 221. 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 surrounding atmosphere is employed as the gas flow generation means 203.

  Note that the gas flow generating means 203 may be constituted by another blower such as a sirocco fan. Moreover, the direction of the injected raw material liquid 300 may be changed by introducing high-pressure gas. Further, a gas flow may be generated inside the guide unit 206 by a suction unit 102 or a second gas flow generation unit 232 described later. In this case, the gas flow generation means 203 does not have a device that actively generates a gas flow. However, in the case of the present invention, the gas flow generation occurs when the gas flow is generated inside the guide means 206. It is assumed that the means 203 exists.

  The depositing means 101 is a member on which nanofibers 301 that are manufactured by electrostatic explosion and fly are deposited. The deposition means 101 is a member that separates and collects the nanofibers 301 guided by the gas flow from the gas flow, and a member that can insert the gas flow and is difficult to insert the nanofiber 301 is employed. In the present embodiment, the deposition means 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 depositing means 101, a long net made of aramid fibers can be exemplified. Furthermore, it is preferable to perform a Teflon (registered trademark) coating on the surface of the deposition unit 101 because the peelability when the deposited nanofiber 301 is peeled off from the deposition unit 101 is improved. Further, the deposition means 101 is supplied from the supply roll 111 in a state of being wound in a roll shape.

  The transport unit 104 is a rotatable roll that pulls out the long deposition unit 101 from the supply roll 111 while winding it and transports the deposition unit 101 together with the nanofibers 301 to be deposited. In the case of the present embodiment, the transport unit 104 is driven by a motor (not shown), and the amount of movement of the deposition unit 101 can be controlled by controlling the motor. The conveyance means 104 can wind up the nonwoven fabric on which the nanofibers 301 are deposited together with the deposition means 101.

  The suction means 102 is disposed on the opposite side of the deposition means 101 to the side on which the nanofibers 301 are deposited, that is, on the opposite side to the side on which the guide means 206 is disposed, and flows from the change section 260 through the acceleration section 265. In this device, the flow is forced to pass through the deposition means 101 and sucked. In the present embodiment, the nanofiber manufacturing apparatus 100 employs a blower such as a sirocco fan or an axial fan as the suction unit 102, and generates a gas flow from the region regulating unit 103 toward the duct 121. The suction means 102 is disposed in communication with the duct 121 and sucks most of the gas flow derived from the acceleration unit 265 and mixed with the solvent evaporated from the raw material liquid 300. It can be conveyed to the solvent recovery apparatus 106 through 121.

  The region regulating unit 103 has a function of regulating the suction region of the suction unit 102, and is located on the opposite side of the deposition unit 101 from the side where the nanofibers 301 are collected, and between the deposition unit 101 and the suction unit 102. The both ends to be arranged are open cylinders. One end portion of the region regulating means 103 is disposed so as to be substantially blocked by the deposition means 101, and the suction means 102 is connected to the other end portion. Accordingly, when the amount of gas flow inserted into the deposition unit 101 decreases, the pressure inside the region regulating unit 103 decreases. The shape of the region regulating means 103 preferably corresponds to the end shape of the guide means 206. In the case of the present embodiment, since the shape of the lead-out end opening of the accelerating portion 265 is rectangular, the region restricting means 103 also employs a rectangular cylinder corresponding to the shape. In addition, if the shape of the lead-out end portion is annular, the region regulating means 103 may be a cylindrical shape.

FIG. 4 is a diagram schematically showing main mechanism units and functional units of the nanofiber manufacturing apparatus.
As shown in the figure, a first pressure measuring means 241 is provided inside the end of the guiding means 206, and a second pressure measuring means 107 is provided inside the region regulating means 103. On the other hand, the nanofiber manufacturing apparatus 100 includes manufacturing condition control means 302 as a functional unit.

  The first pressure measuring unit 241 is a device that measures the pressure inside the guiding unit 206 and in the vicinity of the deposition unit 101 and outputs the first measurement result. Here, the pressure is a pressure generated by a gas flow. The pressure measuring method of the first pressure measuring means 241 is not particularly limited. For example, one using a Bourdon tube, one using a diaphragm, one using a bellows, etc. can be listed.

  The second pressure measuring means 107 is a device that measures the pressure inside the region restricting means 103 and in the vicinity of the deposition means 101 and outputs a second measurement result. The pressure measuring method is the same as that of the first pressure measuring means 241.

  The manufacturing condition control means 302 is a functional unit that controls the nanofiber manufacturing conditions by controlling the mechanical unit of the nanofiber manufacturing apparatus 100, and is a program realized by a computer. The manufacturing condition control unit 302 includes a pressure difference calculation unit 321, a conveyance control unit 322, a suction control unit 323, a charging control unit 324, an injection amount control unit 325, and a flow rate control unit 326.

  The pressure difference calculation unit 321 is a processing unit that calculates the difference between the first measurement result acquired from the first pressure measurement unit 241 and the second measurement result acquired from the second pressure measurement unit 107 and outputs the calculation result. .

  The conveyance control unit 322 is a processing unit that controls the conveyance amount of the nanofibers 301 deposited on the deposition unit 101 based on the calculation result of the pressure difference calculation unit 321, and a motor (not shown) that drives the conveyance unit 104. By controlling and moving the deposition means 101, the transport amount of the nanofiber 301 is controlled. A specific control method will be described later.

  The suction control unit 323 is a processing unit that controls the suction amount of the gas flow by the suction unit 102 based on the calculation result of the pressure difference calculation unit 321, and controls the rotation speed of the fan included in the suction unit 102. The suction volume is controlled.

  The charging control unit 324 is a processing unit that controls the charging amount of the raw material liquid 300 by the charging unit 202 based on the calculation result of the pressure difference calculation unit 321, and controls the output voltage of the induction power supply 222 provided in the charging unit 202 to The amount of charge induced in the means 201 is controlled.

  The injection amount control unit 325 is a processing unit that controls the injection amount of the raw material liquid 300 from the injection unit 201 based on the calculation result of the pressure difference calculation unit 321, and controls the rotation speed of the motor 213 provided in the injection unit 201. The amount of the raw material liquid 300 ejected from the ejection container 211 is controlled.

  The flow rate control unit 326 is a processing unit that controls the flow rate of the gas flowing inside the guide unit 206 based on the calculation result of the pressure difference calculation unit 321, and the rotation of a motor (not shown) provided in the gas flow generation unit 203. The flow rate of gas is controlled by controlling the speed or by controlling the gas pressure of the second gas flow generating means 232.

  In addition, although the pressure of the guide means 206 side and the suction means 102 side was measured and the first measurement result and the second measurement result were calculated, the differential pressure was calculated. However, the present invention is not limited to this. For example, the manufacturing condition control unit 302 does not include the pressure difference calculation unit 321, but receives a measurement result from a differential pressure gauge that can directly measure a pressure difference at two locations, and each control unit has a mechanism based on the received value. The part may be controlled.

  Next, an outline of a manufacturing method of the nanofiber 301 will be described.

  First, a gas flow is generated inside each guide means 206 by each gas flow generation means 203 and second gas flow generation means 232. On the other hand, the gas flow is sucked by the suction means 102 from the downstream side of the deposition means 101.

  Next, the raw material liquid 300 is supplied to each injection container 211. The raw material liquid 300 is separately stored in a tank (not shown), passes through each raw material liquid supply path 217 (see FIG. 2), and is supplied into the injection container 211 from the other end of each injection container 211. . Next, while supplying electric charge to the raw material liquid 300 stored in each injection container 211 by each induction power source 222, each injection container 211 is rotated by each motor 213 and charged from the injection port 216 by centrifugal force. 300 is jetted.

  The raw material liquid 300 injected radially in the radial direction of the injection container 211 has its flight direction changed by the gas flow. The raw material liquid 300 is being changed into nanofibers 301 due to electrostatic explosion, and the nanofibers 301 to be manufactured are guided toward the deposition means 101 by riding in the gas flow in the guide means 206.

  In the case of the present embodiment, since the ejection means 201 is provided in two places, the nanofibers 301 that are emitted from each ejection means 201 and manufactured by electrostatic explosion are joined together with the gas flow by the joining portion 261. . And the inside of the confluence | merging part 261 is carried on a gas flow. At this stage, the nanofiber 301 is in a first stage high density state. Next, the charge of the nanofiber 301 is removed by the static elimination unit 207 and reaches the acceleration unit 265.

  The nanofibers 301 that pass through the inside of the acceleration unit 265 are accelerated by the jet of high-pressure gas, and are gradually compressed as the inside of the acceleration unit 265 narrows to become a high-density state in the second stage. To reach.

  Next, the nanofiber 301 is separated from the gas flow by the deposition unit 101 and deposited on the deposition unit 101, and the gas flow passes through the deposition unit 101 and is sucked by the suction unit 102. Although the deposition means 101 can pass through the gas flow, resistance is generated when the gas flow passes, so that there is a difference in pressure due to the gas flow between the front and the back of the deposition means 101. Further, as the nanofiber 301 is deposited on the deposition means 101, the resistance increases and the pressure difference also increases.

  Finally, the nanofiber 301 sufficiently deposited on the deposition means 101 is transported out of the place where the nanofiber 301 reaches, so that the new nanofiber 301 reaches the portion of the deposition means 101 where the deposition is insufficient. The deposition means 101 is moved.

  Next, control of the conveyance amount of the nanofiber 301 deposited on the deposition unit 101 will be described. Hereinafter, the nanofibers 301 deposited on the deposition unit 101 are referred to as “deposition fibers”.

FIG. 5 is a diagram showing a pressure difference at a position sandwiching the deposition means and a transport speed of the deposition fiber.
The lower graph of the figure shows the pressure difference P calculated by the pressure difference calculation unit 321 based on the measurement results obtained from the first pressure measuring means 241 and the second pressure measuring means 107 on the vertical axis, and the elapsed time on the horizontal axis. It is what I took. The upper graph in the figure shows the same progress as the lower graph, with the vertical axis representing the moving speed of the deposition means 101 controlled by the transport control unit 322 based on the calculation result of the pressure difference calculation unit 321, that is, the transport speed V of the deposited fiber. Time is taken on the horizontal axis.

  As shown in the figure, when the pressure difference P exceeds the first set value P1, the transport controller 322 controls the motor that drives the transport means 104 so that the transport speed of the deposited fiber becomes V (T2). . Since the nanofiber 301 is continuously deposited on the deposition means 101 during this period, the pressure difference P increases. That is, the thickness of the deposition fiber on the deposition unit 101 increases and the passage of the gas flow is hindered.

  Next, when the pressure difference P exceeds the second set value P2, the transport speed V is gradually increased. As a result, the thin portion of the deposited fiber increases, and the pressure difference P starts to decrease at a certain time. When the pressure difference P falls below the second set value P2, the conveyance speed V is kept constant as V (T4).

  Next, when the pressure difference P falls below the first set value P1, the transport speed V is gradually decreased. When the pressure difference exceeds the first set value P1, the conveyance speed V is kept constant as V (T5).

  By repeating the above steps, the transport speed, which is the transport amount per unit time, of the deposited nanofibers is controlled so that the pressure difference P does not become higher than the set upper limit value Pmax and does not become lower than the set lower limit value Pmin. It becomes possible. As a result, it is possible to stably supply a long deposited nanofiber having a constant ventilation performance within a predetermined range.

  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, nylon, aramid, Polycaprolactone, Polylactic acid, Polyglycolic acid, Collagen, Polyhydroxybutyric acid, Polyvinyl acetate, Polypeptide Etc. can be exemplified. Moreover, the kind selected from the above may be used, and a plurality of kinds may be mixed. Note that the above is an example, and the present invention is not limited to the above polymer substance.

  Solvents used for the raw material liquid 300 include methanol, ethanol, 1-propanol, 2-propanol, hexafluoroisopropanol, tetraethylene glycol, triethylene glycol, dibenzyl alcohol, 1,3-dioxolane, 1,4-dioxane. Methyl ethyl ketone, methyl isobutyl ketone, methyl-n-hexyl ketone, methyl-n-propyl ketone, diisopropyl ketone, diisobutyl ketone, acetone, hexafluoroacetone, phenol, formic acid, methyl formate, ethyl formate, propyl formate, methyl benzoate, Ethyl benzoate, propyl benzoate, methyl acetate, ethyl acetate, propyl acetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, methyl chloride, ethyl chloride, methylene chloride, chloroform , O-chlorotoluene, p-chlorotoluene, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane, dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethyl bromide, odor Propyl chloride, acetic acid, benzene, toluene, hexane, cyclohexane, cyclohexanone, cyclopentane, o-xylene, p-xylene, m-xylene, acetonitrile, tetrahydrofuran, N, N-dimethylformamide, pyridine, water, etc. it can. 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.

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. Note that the above is an example, and the present invention is not limited to the above polymer substance.

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

(Embodiment 2)
Next, another embodiment according to the present invention will be described.

  FIG. 6 is a cross-sectional view schematically showing a nanofiber manufacturing apparatus according to an embodiment of the present invention.

  The nanofiber manufacturing apparatus 100 shown in the figure is substantially the same as the nanofiber manufacturing apparatus 100 shown in the first embodiment. The difference from the first embodiment is that the diffusion unit 266 exists in the guide unit 206 and the shape of the region regulating unit 103. Therefore, only differences will be described in the second embodiment.

  The diffusing unit 266 is provided following the accelerating unit 265 and is a part that diffuses the nanofiber 301 widely, and is a hood-like part that decelerates the speed of the nanofiber 301 accelerated by the accelerating unit 265. The diffusion unit 266 includes a rectangular opening on the upstream end side where the gas flow is introduced and a rectangular opening on the downstream end side from which the gas flow is discharged, and the opening area of the opening on the downstream end side is upstream. It is set to be larger than the opening area of the opening on the end side. The diffusing portion 266 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 corresponding to the width of the deposition unit 101 and has a shape that extends long in the moving direction of the deposition unit 101.

  The region regulating means 103 includes an opening having the same shape and the same area as the outlet side opening end of the diffusing means 240 on the deposition means 101 side, and the opening on the side connected to the suction means 102 corresponds to the suction means 102. It is circular.

  Next, control of the transport amount of the nanofibers 301 deposited on the deposition unit 101 when using the nanofiber manufacturing apparatus 100 according to the second embodiment will be described.

FIG. 7 is a diagram illustrating a pressure difference at a position sandwiching the deposition unit and a transport speed of the deposition fiber.
The lower graph of the figure shows the pressure difference P calculated by the pressure difference calculation unit 321 based on the measurement results obtained from the first pressure measuring means 241 and the second pressure measuring means 107 on the vertical axis, and the elapsed time on the horizontal axis. It is what I took. The upper graph in the figure shows the same progress as the lower graph, with the vertical axis representing the moving speed of the deposition means 101 controlled by the transport control unit 322 based on the calculation result of the pressure difference calculation unit 321, that is, the transport speed V of the deposited fiber. Time is taken on the horizontal axis.

  As shown in the figure, until the pressure difference P exceeds the set upper limit value Pmax, the transport speed of the deposition fiber is zero, that is, the transport control unit 322 is a motor that drives the transport unit 104 so that the deposition unit 101 does not move. To control.

  Next, when the pressure difference P exceeds the set upper limit value Pmax, the deposited fiber is transported. The deposited fiber conveyance amount is not less than the length of the guide unit 206 in the moving direction of the leading end portion of the guide unit 206, that is, the deposition unit 101 of the diffusion unit 266. During the transfer of the volume fiber, the transfer control unit 322 controls the motor that drives the transfer unit 104 to move the transfer unit 104 at the speed Va.

  By repeating the above steps, it is possible to stably supply short deposited nanofibers whose ventilation performance is constant within a predetermined range, and the performance of the obtained short volume nanofibers over a wide range in the surface direction. It becomes possible to supply a stable volume nanofiber.

  In the second embodiment, the nanofiber 301 joined by the joining means 130 is connected to the accelerating means 230, and then the nanofiber 301 is diffused by the diffusing means 240. However, the nanofiber 301 is joined by the joining means 130. The nanofiber 301 may be directly connected to the diffusion means 240 and the nanofiber 301 may be deposited on the deposition means 101.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a nanofiber manufacturing apparatus, an apparatus for spinning using the manufactured nanofiber, an apparatus for manufacturing a nonwoven fabric using the manufactured nanofiber, and the like.

It is sectional drawing which shows typically the nanofiber manufacturing apparatus which is embodiment of this invention. It is sectional drawing which shows a discharge | release means. It is a perspective view which shows discharge | release means. It is a figure which shows typically the main mechanism part and function part of a nanofiber manufacturing apparatus. It is a figure which shows the pressure difference of the position which pinched | interposed the deposition means, and the conveyance speed of deposition fiber. It is sectional drawing which shows typically the nanofiber manufacturing apparatus which is embodiment of this invention. It is a figure which shows the pressure difference of the position which pinched | interposed the deposition means, and the conveyance speed of deposition fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Nanofiber manufacturing apparatus 101 Deposition means 102 Suction means 103 Area | region control means 104 Conveyance means 106 Solvent recovery apparatus 107 2nd pressure measurement means 111 Supply roll 121 Duct 201 Injection means 202 Charging means 203 Gas flow generation means 206 Guiding means 207 Static elimination means 211 Injection container 212 Rotating shaft body 213 Motor 216 Injection port 217 Raw material liquid supply path 221 Induction electrode 222 Induction power source 223 Grounding means 232 Second gas flow generation means 233 Gas flow introduction port 235 Valve 240 Diffusion means 241 First pressure measurement means 260 Change unit 261 Junction unit 264 Neutralization unit 265 Acceleration unit 266 Diffusion unit 300 Raw material liquid 301 Nanofiber 302 Manufacturing condition control means 321 Pressure difference calculation unit 322 Transport control unit 323 Suction control unit 324 Charging control unit 32 Injection amount control section 326 flow rate controller

Claims (5)

An injection means for injecting a raw material liquid as a raw material of the nanofiber into the space;
Charging means for charging by charging the raw material liquid;
A gas flow generating means for generating a gas flow for guiding the nanofibers;
Sheet-like deposition means capable of depositing the nanofibers and allowing the gas flow to pass through;
Transport means for transporting the deposited nanofibers by moving the deposition means;
Guiding means for forming a wind tunnel for guiding the nanofibers produced by the ejection means to the deposition means;
A suction means arranged on the opposite side of the guide means with respect to the deposition means, for sucking the gas flow;
Area regulating means for regulating the suction area of the suction means;
First pressure measuring means for measuring the pressure of the gas flow inside the guiding means;
Second pressure measuring means for measuring the pressure of the gas flow inside the region regulating means;
Production condition control means for controlling the nanofiber production conditions based on the difference between the first measurement result of the first pressure measurement means and the second measurement result of the second pressure measurement means ,
The guide means includes a diffusion portion that diffuses nanofibers widely, with the opening area of the opening portion on the downstream end side being larger than the opening area of the opening portion on the upstream end side,
The region regulating means includes an opening having the same shape and area as the opening on the downstream end side of the diffusion portion,
The manufacturing condition control means transports a predetermined amount when a pressure difference, which is a difference between the first measurement result and the second measurement result, is higher than a predetermined set upper limit value, and the pressure difference is set to the set upper limit value. A nanofiber manufacturing apparatus comprising transport control means for controlling the transport means so as not to transport while lower than the value . An injection means for injecting a raw material liquid as a raw material of the nanofiber into the space; a charging means for applying an electric charge to the raw material liquid for charging; a gas flow generating means for generating a gas flow for guiding the nanofiber; Sheet-like deposition means capable of depositing the nanofibers and allowing the gas flow to pass therethrough, transport means for transporting the deposited nanofibers by moving the deposition means, and nanofibers manufactured by the ejection means Guide means for forming a wind tunnel for guiding to the deposition means, suction means for sucking the gas flow, disposed on the opposite side to the guide means with respect to the deposition means, and region regulation for regulating the suction region of the suction means and means, a first pressure measuring means for measuring the pressure of said guiding means inwards of the gas flow, and a second pressure measuring means for measuring the pressure of the region restricting means inwardly of the gas flow, the The inner means includes a diffusion portion in which the opening area of the opening portion on the downstream end side is larger than the opening area of the opening portion on the upstream end side and diffuses nanofibers widely, and the region regulating means includes the downstream end of the diffusion portion. a nano-fiber manufacturing method using the same shape as the opening of the side, the device for production of nanofibres of Ru with an opening of the same area,
A pressure difference calculation step of calculating a difference between the first measurement result of the first pressure measurement means and the second measurement result of the second pressure measurement means as a pressure difference;
Manufacturing that transports a predetermined amount when the calculated pressure difference becomes higher than a predetermined set upper limit, and controls the transport means so as not to carry while the pressure difference is lower than the set upper limit. A nanofiber manufacturing method including a condition control step. The manufacturing condition control step includes
The nanofiber manufacturing method according to claim 2 , further comprising an injection control step of controlling an injection amount of the raw material liquid in the injection means. The manufacturing condition control step includes
The nanofiber manufacturing method according to claim 2 , further comprising a flow rate control step of controlling a flow rate of the gas flow in the gas flow generation means. The manufacturing condition control step includes
The nanofiber manufacturing method according to claim 2 , further comprising an injection control step of controlling the number of rotations of the injection container when the injection means is an injection means that rotates the injection container to inject from a small hole.

Images