JP5215106B2 - Nanofiber manufacturing apparatus and nanofiber manufacturing method - Google Patents

Description

  The present invention relates to a nanofiber manufacturing apparatus, and more particularly, to a nanofiber manufacturing apparatus including a charging electrode at a position different from a position where nanofibers are collected, and a nanofiber manufacturing method using the nanofiber manufacturing measure.

  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 electrically stretching the raw material liquid therein.

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

In order to improve the production efficiency of nanofibers manufactured by the electrospinning method as described above, it is sufficient to increase the raw material liquid that flows out into the space. Accordingly, the inventors of the present application can cause a large amount of raw material liquid to exist in the space by causing the raw material liquid to flow out into the space from a large number of holes and changing the flight direction of the discharged raw material liquid by the gas flow. We have proposed a nanofiber manufacturing device.
JP 2008-31624 A

  However, while the inventors of the present application are using the above-described nanofiber manufacturing apparatus, even if a part of the raw material liquid that has flowed into the space does not cause an electrostatic stretching phenomenon or an electrostatic stretching phenomenon occurs. A phenomenon has been found in which the chain of electrostatic stretching phenomenon does not occur as the desired fineness is reached.

  Accordingly, the inventors of the present application have further advanced experiments and research, and have found that the above phenomenon occurs when the amount of charge applied to the flowing out raw material liquid is biased depending on the position of the flowing out hole.

  The present invention has been made on the basis of the above findings, and an object of the present invention is to provide a nanofiber manufacturing apparatus capable of averaging the amount of charge applied to the raw material liquid and improving the nanofiber production efficiency.

  In order to achieve the above object, a nanofiber manufacturing apparatus according to the present invention is a nanofiber manufacturing apparatus for manufacturing nanofibers by electrically stretching a raw material liquid in a space, and the raw material liquid flows out into the space. An outflow body having a plurality of outflow holes, a charging electrode arranged at a predetermined interval from the outflow body, and applying a predetermined voltage to the outflow body, and the outflow body and the charging electrode A charging power source for setting a predetermined voltage between the charging power source and a gas flow generating means for generating a gas flow for transporting the nanofibers manufactured from the raw material liquid flowing out from the effluent. Is arranged on the windward side of the gas flow generated by the gas flow generating means, and the opening end of the outflow hole is arranged so that the distance between the opening end of the outflow hole and the charging electrode is equal to each other. Features.

  Thereby, since the distance between the charging electrode and the opening end of the outflow hole becomes the same, the charge applied to the raw material liquid flowing out through the outflow hole can be averaged. Therefore, most of the raw material liquid flowing out into the space is electrically stretched, and the production efficiency of the nanofiber can be improved.

  Further, the outflow body has a hole vicinity portion that forms the outflow hole, and the hole vicinity portion is closer to the charging electrode than a portion other than the hole vicinity portion of the outflow body. Is preferred.

  As a result, the charge concentrates in the vicinity of each hole, so that the raw material liquid can be charged efficiently, and the raw material liquid can be charged with a high charge density. In addition, since the amount of charge applied to the raw material liquid is averaged, many of the raw material liquids flowing into the space cause a chain of electrostatic stretching phenomena at a high level, producing high-quality nanofibers with high production efficiency. It becomes possible to do.

  The outflow holes are arranged at a plurality of locations in a state of opening radially on the circumferential surface of the cylinder, and are also arranged in the axial direction of the cylinder. The charging electrode is annular, and the gas flow is generated. The means may be arranged such that a gas flow flows in a space surrounded by the charging electrode.

  Thereby, a raw material liquid can be efficiently flowed out to space, and it becomes possible to convey a raw material liquid and nanofiber to a predetermined place.

  Furthermore, it is preferable that a driving unit that rotates the outflow body in a state where the distance relationship between the outflow hole and the charging electrode is maintained is provided.

  Thereby, an outflow body can be made to flow out radially in space with a simple composition, without using a pump etc.

  Furthermore, a supply path for supplying the raw material liquid to the inside of the outflow body, and a portion for receiving the raw material liquid discharged from the supply path on the inner periphery of the outflow body, which is oblique to the discharge direction of the raw material liquid It is preferable to provide a liquid receiving part that receives the raw material liquid on the intersecting surface.

  Accordingly, when the raw material liquid is supplied into the outflow body, it is possible to avoid a situation where the raw material liquid is splashed on the inner surface of the outflow body and the raw material liquid is not evenly supplied to the plurality of outflow holes. .

  The outflow hole is disposed in a direction in which the raw material liquid flows from the liquid receiving unit, and is disposed in a recess in which a liquid pool of the raw material liquid is formed, and the supply path is provided for each of the plurality of liquid receiving units. It is preferable to provide a plurality of supply ports for discharging water.

  Thereby, a raw material liquid can be efficiently supplied with respect to many outflow holes, and a raw material liquid can be flowed out in space in the stable state. Therefore, the state of the flowing out raw material liquid is stabilized, and it becomes possible to efficiently produce high-quality nanofibers.

  Further, a nanofiber manufacturing method according to the present invention for achieving the above object is a nanofiber manufacturing method for manufacturing a nanofiber by electrically stretching a raw material liquid in a space, wherein a plurality of outflow holes are formed. An outflow step for causing the raw material liquid to flow out into the space from the outflow body, a gas flow generation step for generating a gas flow for transporting nanofibers manufactured from the raw material liquid flowing out of the outflow body by the gas flow generation means, and A charging step of charging a raw material liquid by applying a predetermined voltage to the outflow body on a charging electrode arranged on the windward side of the gas flow from the outflow hole with a predetermined distance from the outflow body, In the outflow step, the raw material liquid is caused to flow out from the opening end of the outflow hole having the same distance from the charging electrode.

  Thereby, since the distance between the charging electrode and the opening end of the outflow hole is the same, the charge applied to the raw material liquid flowing out through the outflow hole can be averaged. Accordingly, most of the raw material liquid flowing out into the space causes an electrostatic stretching phenomenon, and it becomes possible to improve the production efficiency of the nanofiber.

  According to the present invention, the raw material liquid flowing out into the space from the plurality of outflow holes can be charged with an equal charge amount. As a result, most of the raw material liquid that flows out can be electrically stretched to produce nanofibers, and the production efficiency of nanofibers can be improved.

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

  FIG. 2 is a cross-sectional view schematically showing the nanofiber manufacturing apparatus according to the embodiment of the present invention from the upper surface.

  As shown in these drawings, the nanofiber manufacturing apparatus 100 includes a discharge means 200, a guide body 206, a diffusion means 240, a collection means 110, and an attracting means 120.

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

FIG. 3 is a cross-sectional view showing the discharging means.
FIG. 4 is a perspective view showing the discharging means.

  As shown in these drawings, the discharge means 200 is a unit that can discharge the charged raw material liquid 300 and the manufactured nanofibers 301 on a gas flow. The discharge means 201, the charging means 202, A wind tunnel body 209, a gas flow generation means 203, and a supply path 217 are provided.

  The charging unit 202 is a device that charges the raw material liquid 300 by applying an electric charge. In the case of the present embodiment, the charging unit 202 includes a charging electrode 221, a charging power source 222, and a grounding unit 223.

  The charging electrode 221 is a member for inducing electric charges to the grounded outflow body 211 when the charging electrode 221 itself becomes a high voltage or a low voltage with respect to the ground. In the case of the present embodiment, the charging electrode 221 is an annular member disposed so as to surround the periphery of the outflow body 211. Further, as shown in FIGS. 1, 2, and 3, the charging electrode 221 has a circular cross section. When a positive voltage is applied to the charging electrode 221, a negative charge is induced in the outflow body 211, and when a negative voltage is applied to the charging electrode 221, a positive charge is induced in the outflow body 211. .

The positional relationship between the charging electrode 221 and the outflow body 211 will be described later.
Although the size of the charging electrode 221 needs to be larger than the diameter of the outflow body 211, it is preferable that the diameter is adopted from the range of 50 mm or more and 1500 mm or less. Note that the shape of the charging electrode 221 is not limited to an annular shape, and may be a polygonal annular shape or a flat plate shape depending on the relationship with the shape of the outflow body 211.

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

  The charging power source 222 is a power source that can apply a high voltage to the charging electrode 221. In general, the charging power source 222 is preferably a DC power source. 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. Further, when the charging power source 222 is a DC power source, the voltage applied to the charging electrode 221 by the charging power source 222 is preferably set from a value in the range of 10 KV or more and 200 KV or less. When a negative voltage is applied to the charging power source 222, the polarity of the applied voltage becomes negative. In particular, the electric field strength between the outflow body 211 and the charging electrode is important, and the applied voltage is adjusted so that the electric field strength is 1 KV / cm or more in the space where the distance between the charging electrode 221 and the outflow body 211 is the closest. Is preferred.

  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 effluent 211 at the ground potential. If the outflow body 211 is in a ground potential state, it is not necessary to electrically insulate members such as the rotating shaft body 212 and the motor 213 connected to the outflow body 211 from the outflow body 211, and the outflow unit 201 has a simple structure. Can be adopted, which is preferable.

  As the charging means 202, a charge may be applied to the raw material liquid 300 by connecting a power source to the effluent 211, maintaining the effluent 211 at a high voltage, and grounding the charging electrode 221. In addition, the outflow body 211 is formed of an insulator, and an electrode that is in direct contact with the raw material liquid 300 stored in the outflow body 211 is disposed inside the outflow body 211, and charges are applied to the raw material liquid 300 using the electrodes. It may be a thing. When an electrode is arranged directly on the effluent 211 or directly on the raw material liquid, the polarity of the charge charged in the raw material liquid is the same as the polarity of the applied voltage.

  The outflow means 201 is a device that causes the raw material liquid 300 to flow out into the space. In this embodiment, the outflow means 201 is a device that causes the raw material liquid 300 to flow out radially by centrifugal force and outflows the raw material liquid to the inside of the charging electrode 221. is there. The outflow means 201 includes an outflow body 211, a rotary shaft body 212, and a motor 213 as a drive means. The rotating shaft body 212 is rotatably supported by a support body (not shown) via a bearing 215.

  The outflow body 211 is a member for causing the raw material liquid 300 to flow out into the space, and is a container that can temporarily store the raw material liquid 300. The outflow body 211 is a member provided with a large number of outflow holes 216 through which the raw material liquid 300 passes from the inside toward the outside. The outflow body 211 has a hole vicinity portion 218 that forms an outflow hole 216. Further, the hole vicinity portion 218 is arranged so that the distance from the charging electrode 221 is closer than the portion of the effusing body 211 other than the hole vicinity portion 218. In the case of the present embodiment, the outflow body 211 includes a cylindrical base 219 and a protrusion 220 that is provided at the end of the base 219 and projects radially over the entire circumference of the base 219. Includes a hole vicinity 218. A plurality of protrusions 220 are provided side by side in the axial direction.

  The protrusion 220 has an annular shape, and the cross section has a triangular shape that is pointed outward. Accordingly, the protruding portion 220 includes an annular ridge line portion at the outer end, and the ridge line portion becomes the hole vicinity portion 218. A plurality of outflow holes 216 are provided in the hole vicinity portion 218 along the ridgeline.

  Therefore, the distance between the hole vicinity portion 218 forming the outflow hole 216 and the charging electrode 221 disposed so as to surround the outflow body 211 is the distance between the portion other than the hole vicinity portion 218 of the outflow body 211 and the charging electrode 221. Shorter than. In particular, in the protruding portion 220, the portion other than the hole vicinity portion 218 of the outflow body 211 is set so that the distance from the charging electrode 221 gradually increases as the distance from the hole vicinity portion 218 increases.

  That is, the outflow body 211 has a shape in which the opening end of the outflow hole 216 is closest to the charging electrode 221, and the distance between the opening end of all the outflow holes 216 and the charging electrode 221 is equal. Such a shape is adopted. Further, the outflow body 211 is arranged in a positional relationship with the charging electrode 221 so that the opening end of the outflow hole 216 is closest to the charging electrode 221. In the case of the present embodiment, the outflow body 211 has a shape in which the open end of the outflow hole 216 is positioned on the circumference centered on the cross section of the charging electrode 221, and the open end of the outflow hole 216 is arranged. The shape in which the part of the outflow body 211 does not exist is adopted in the circle.

  In the present embodiment, the outer shape of the outflow body 211 has been described as a shape in which the cylindrical base 219 and the annular protrusion 220 are combined, but the present invention is not limited to this. For example, the outer shape of the outflow body 211 may be a shape in which a cylindrical base body 219 and a plurality of projecting portions 220 such as a cylinder, a cone, and a pyramid are combined. In this case, the protrusion 220 is provided in the radial direction on the peripheral wall of the base 219, and the outflow hole 216 is provided at the tip of the protrusion 220. Even the outflow body 211 having such an outer shape can be arranged so that the opening end of the outflow hole 216 is closest to the charging electrode 221.

  In the case of the present embodiment, the effluent 211 is a container that can cause 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 the effluent 211 is supported. It is rotatably supported by a bearing 215 provided on the body (not shown). The rotating shaft 212 may be rotatably supported by a support (not shown) by a bearing (not shown).

  The outflow body 211 has a liquid receiving part 224 at a plurality of locations in the internal shape. The liquid receiving unit 224 is a portion where a raw material liquid 300 supplied from a supply path 217 to be described later hits, and an outflow body 211 having a surface that obliquely intersects the supply direction of the raw material liquid 300 discharged from the supply path 217. It is a part of. In the case of the present embodiment, the liquid receiving part 224 is provided inward of the protruding part 220, and is provided in parallel with the inclined surface outside of the protruding part 220.

  The supply path 217 is provided with a plurality of supply ports 228 so that the raw material liquid 300 can be supplied to the liquid receivers 224 provided at a plurality of locations.

  Furthermore, the outflow body 211 has a recess 225 in its internal shape. The recess 225 is recessed in the direction of the centrifugal force generated when the outflow body 211 rotates, and functions as a liquid reservoir in which the raw material liquid 300 is stored in the state where the outflow body 211 is rotating. An outflow hole 216 is provided at the distal end of the concave portion 225 in the centrifugal force direction.

  Moreover, the liquid receiving part 224 forms a part of the recessed part 225, and the raw material liquid 300 which contacted the liquid receiving part 224 accumulates smoothly in the recessed part 225 by centrifugal force.

  In addition, the outflow body 211 is formed of a conductor in order to impart electric charge to the stored raw material liquid 300, and the outflow body 211 also functions as a part of the charging unit 202.

  Specifically, it is preferable that the diameter of the portion where the outflow hole 216 of the outflow body 211 is arranged is adopted from a range of 10 mm or more and 300 mm or less. This is because if it is too large, it will be difficult to concentrate the raw material liquid 300 and the nanofiber 301 by the gas flow described later, and if the weight balance is slightly deviated, such as the rotational axis of the effluent 211 is deviated, a large vibration will occur. This is because a structure that firmly supports the outflow body 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 load and vibration of the drive source. Furthermore, it is preferable that the diameter of the part where the outflow hole 216 of the outflow body 211 is arranged is adopted from the range of 20 mm or more and 100 mm or less.

  In addition, the shape of the outflow hole 216 is preferably circular, and the diameter thereof is preferably from about 0.01 mm to 3 mm, although it depends on the thickness of the outflow body 211. This is because if the outflow hole 216 is too small, it is difficult to cause the raw material liquid 300 to flow out of the outflow body 211, and if it is too large, the unit of the raw material liquid 300 that flows out from one outflow hole 216. This is because the amount per hour becomes too large (that is, the thickness of the line formed by the flowing out raw material liquid 300 becomes too thick), making it difficult to manufacture the nanofiber 301 having a desired diameter.

  In addition, the outflow body 211 is not only a member that causes the raw material liquid 300 to flow out into the space by the centrifugal force of its own rotation, but is also stationary and the pressurized raw material liquid 300 flows out from the outflow hole 216. A member may be used. Moreover, the shape of the outflow body 211 that causes the raw material liquid 300 to flow out by centrifugal force is not limited to a cylindrical shape, and may be a polygonal cylindrical shape having a polygonal cross section or a conical shape. Any shape may be used as long as the raw material liquid 300 can flow out of the outflow hole 216 by centrifugal force when the outflow hole 216 rotates. Further, the shape of the outflow hole 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 body 211 and causing the raw material liquid 300 to flow out by centrifugal force, and is inserted into the outflow body 211 from the other end of the outflow body 211. This is a rod-like body in which the closed portion and one end portion of the outflow body 211 are joined. The other end is joined to the rotating shaft of the motor 213.

  The motor 213 is a driving device that applies a rotational driving force to the outflow body 211 via the rotating 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 body 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 efflux body 211 are in linear motion as in the present embodiment, the rotational speed of the motor 213 matches the rotational speed of the efflux body 211.

  The gas flow generation means 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 body 211 to the direction guided by the guide body 206. The gas flow generation means 203 is provided on the back of the motor 213 and generates a gas flow from the motor 213 toward the tip of the effluent 211. The gas flow generating means 203 is capable of generating wind power that can change the raw material liquid 300 flowing out from the outflow body 211 in the radial direction in the axial direction. In FIG. 3, 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 unit 200 is employed as the gas flow generation unit 203.

  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 guide body 206 by the suction means 102 or the like. In this case, the gas flow generating means 203 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 guide body 206. It is assumed that the means 203 exists. In addition, there is a gas flow generating means in which a gas flow is generated inward of the wind tunnel body 209 and the guide body 206 by suction by the suction means 102 without the gas flow generating means 203. It shall be. Further, when a gas flow is generated inside the wind tunnel body 209 or the guide body 206 by suction by the suction means 102 without the gas flow generation means 203, the suction means 102 functions as the gas flow generation means. It is assumed that

  Here, the positional relationship between the charging electrode 221 and the outflow hole 216 provided in the outflow body 211 will be described.

  The charging electrode 221 is disposed on the windward side of the gas flow generated by the gas flow generation means 203 through the outflow hole 216 provided in the outflow body 211 (shown by a white arrow in FIGS. 1, 2, and 3). The That is, in the positional relationship between the charging electrode 221 and the outflow hole 216, the gas flow generation unit 203 generates a gas flow so that the gas flow flows from the charging electrode 221 toward the outflow hole 216.

  According to the positional relationship between the charging electrode 221 and the outflow hole 216 in this embodiment, when the raw material liquid 300 flowing out from the outflow hole 216 in the radial direction by centrifugal force is directed to the charging electrode 221, the gas flow generating means 203 is generated. It will fly against the gas flow. Accordingly, the raw material liquid 300 receives a large drag from the gas flow, and the flight direction is changed before reaching the charging electrode 221. Therefore, the raw material liquid 300 and the nanofibers 301 are difficult to adhere to the charging electrode 221, and most of the raw material liquid 300 that has flowed into the space is recovered as nanofibers 301 due to the electrostatic stretching phenomenon. That is, the production efficiency of the nanofiber 301 can be increased.

  The wind tunnel body 209 is a conduit that guides the gas flow generated by the gas flow generation means 203 from the charging electrode 221 to the vicinity of the outflow hole 216 of the outflow body 211. In the case of the present embodiment, the gas flow guided by the wind tunnel body 209 intersects with the raw material liquid 300 flowing out from the outflow hole 216 of the outflow body 211 after passing through the inside of the charging electrode 221, and Change the flight direction.

  Furthermore, the discharge unit 200 includes a gas flow control unit 204 and a heating unit 205.

  The gas flow control unit 204 has a function of controlling the gas flow so that the gas flow generated by the gas flow generation unit 203 does not hit the opening end of the outflow hole 216. In the case of the present embodiment, as the gas flow control means 204, an air passage body that guides the gas flow so as to flow in 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 arranged inside the guide body 206 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.

Returning to FIG. 1 and FIG.
The guide body 206 is a wind tunnel that guides the nanofiber 301 emitted from the emission means 200 to a predetermined place. The guide body 206 in the present embodiment is a cylindrical body, has the same opening shape as that of the emitting means 200 on the side where the nanofibers 301 are emitted, and is arranged in series with the emitting means 200.

  The diffusing unit 240 is a conduit connected to the guide body 206 and diffusing the nanofibers 301 in a high density state widely and evenly into a low density state. The space in which the nanofibers 301 are guided is smoothly and continuously. By expanding, it is a hood-like member that gradually reduces the velocity of the gas flow conveying the nanofiber 301 and the velocity of the nanofiber 301.

  The collecting unit 110 is a device for collecting the nanofibers 301 emitted from the diffusing unit 240, and includes a member 101 to be deposited, a transfer unit 104, and a supply unit 111.

  The member to be deposited 101 is a member on which nanofibers 301 that are manufactured and fly by an electrostatic stretching phenomenon are deposited. In the case of the present embodiment, the member to be deposited 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 member 101 to be deposited, 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 member 101 to be deposited because the peelability when the deposited nanofiber 301 is peeled off from the member 101 to be deposited is improved. The member 101 to be deposited is supplied from the supply unit 111 in a state of being wound in a roll shape.

  The transfer means 104 is a device that can transfer the deposition target member 101. In the case of the present embodiment, the member to be deposited 101 is conveyed together with the nanofibers 301 to be pulled out from the supply means 111 while winding the long member to be deposited 101. The transfer means 104 is capable of winding the nanofibers 301 deposited in the form of a nonwoven fabric together with the member to be deposited 101.

  The attracting means 120 is a device for attracting the nanofiber 301 flying in the space to a predetermined place. Examples of a method for attracting the nanofiber 301 include a method for attracting the nanofiber 301 by sucking a gas flow and a method for attracting the charged nanofiber 301 by an electric field (electric field). In the case of the present embodiment, the attracting means 120 employs a device that can selectively and simultaneously implement a method of sucking a gas flow and a method of attracting by electrolysis, An attraction electrode 121 and an attraction power source 122 are provided.

  The suction means 102 is a device that forcibly sucks the gas flow that passes through the deposition target member 101. In the present embodiment, the suction means 102 includes a funnel-shaped hood 103 and a blower 105. The blower 105 is a blower such as a sirocco fan or an axial fan, and is a device that can generate a gas flow from the deposition target member 101 toward the blower 105.

  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 attracting electrode 121 is an electrode for generating an electric field for attracting the charged nanofiber 301. In the case of the present embodiment, a metal net capable of passing a gas flow is employed.

  The attraction power source 122 is a DC power source that can maintain the attraction electrode 121 at a predetermined voltage and polarity. In the case of the present embodiment, the attraction power source 122 is a DC power source that can freely change the voltage and polarity in the range of 0 V (grounded state) to 200 KV or less.

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

First, the gas flow generating means 203 generates a gas flow from the charging electrode 221 toward the outflow hole 216 of the outflow body 211 and passing through the inside of the guide body 206 (gas flow generation step). On the other hand, the gas flow generated in the guide body 206 is sucked by the suction means 102. In the above state, the air volume in the guide body 206 was adjusted to be 30 m ³ / min.

  Next, the raw material liquid 300 is supplied to the inside of the outflow body 211 (raw material liquid supply process). The raw material liquid 300 is separately stored in a tank (not shown), passes through a supply path 217 (see FIG. 3), and is supplied into the effluent 211 from the other end of the effluent 211. The raw material liquid 300 discharged from the plurality of supply ports 228 of the supply path 217 hits the liquid receiving portions 224 provided at a plurality of locations, flows along the liquid receiving portions 224, and is stored in the concave portions 225 provided inside the outflow body 211. Is done. Specifically, PVA (polyvinyl alcohol) is selected as the material of the nanofiber 301, and the raw material liquid 300 is a solvent in which water is used as a solvent and PVA is dissolved in water at 10% by weight.

  Next, the charging power source 222 sets the charging electrode 221 to a positive or negative high voltage. Charge concentrates on the hole vicinity part 218 of the outflow body 211 closest to the charging electrode 221, and charges are evenly concentrated on the hole vicinity part 218 provided in the plurality of protrusions 220 because the distance to the charging electrode 221 is equal. . The charge is transferred to the raw material liquid 300 passing through the outflow hole 216, and the raw material liquid 300 is charged (charging process). In this way, the charge concentrates in the hole vicinity 218 and the raw material liquid 300 is charged by the electric charge, so that the raw material liquid 300 flows out into the space in a strong charged state (high charge density). In addition, since the raw material liquid 300 is charged with an equal charge amount, the raw material liquid 300 flows out into the space with an equal charge density.

  At the same time as the charging step, the outflow body 211 is rotated by the motor 213, and the charged raw material liquid 300 flows out from the outflow hole 216 by centrifugal force (outflow step).

  Specifically, an outflow body 211 having an outer diameter of the protrusion 220 of 60 mm was used. Twelve outflow holes 216 provided at the distal end of the protrusion 220 in the centrifugal force direction were provided at equal intervals in the circumferential direction, and the hole diameter was 0.3 mm. Moreover, the raw material liquid 300 was made to flow out by rotating the outflow body 211 at 2000 rpm. On the other hand, the charging electrode 221 having an inner diameter of Φ600 mm was used, and the charging electrode 221 was made negative 60 KV with respect to the ground potential by the charging power source 222. As a result, positive charge is induced in the effluent 211, and the positively charged raw material liquid 300 flows out.

  The raw material liquid 300 that has flowed radially in the radial direction of the outflow body 211 is changed in flight direction by the gas flow and is guided by the wind tunnel body 209 in the gas flow. Here, since the charged state of the raw material liquid 300 and the charging electrode 221 have opposite polarities, it is attracted by the Coulomb force and tries to fly toward the charging electrode 221, but most of the raw material liquid toward the charging electrode 221 is used. 300 is pushed back by the gas flow and flies toward the guide body.

  The raw material liquid 300 is discharged from the discharge means 200 while manufacturing the nanofiber 301 by the electrostatic stretching phenomenon (nanofiber manufacturing process). Here, in the raw material liquid 300, an electrostatic stretching phenomenon easily occurs in a strong charged state (high charge density), and most of the raw material liquid 300 that flows out changes to the nanofibers 301. In addition, since the raw material liquid 300 flows out in a strong charged state (high charge density), an electrostatic stretching phenomenon occurs over many orders, and a large amount of nanofibers 301 with a small wire diameter are manufactured. Furthermore, since the raw material liquid 300 flows out in an equal charged state, the electrostatic stretching phenomenon occurs in a state where all the raw material liquids 300 are in an equal state.

  In addition, the gas flow is heated by the heating means 205, and while the flight of the raw material liquid 300 is guided, heat is applied to the raw material liquid 300 to promote the evaporation of the solvent and promote the electrostatic stretching phenomenon.

  The nanofiber 301 emitted from the emission means 200 as described above is introduced into the guide body 206. The nanofiber 301 is guided while being conveyed in the gas flow inside the guide body 206 (conveying step).

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

  In this state, the suction means 102 disposed behind the deposition target member 101 sucks the gas flow together with the solvent that is the evaporated component, and attracts the nanofiber 301 onto the deposition target member 101 (attraction process). . In addition, an electric field is generated by the attracting electrode 121 to which a voltage is applied, and the nanofiber 301 is also attracted by the electric field (attraction process).

  As described above, the nanofibers 301 are deposited on the deposition target member 101 (deposition step). Since the member 101 to be deposited is slowly transferred by the transfer means 104, the nanofiber 301 is also collected as a long belt-like member extending in the transfer direction.

  By manufacturing the nanofiber 301 using the nanofiber manufacturing apparatus 100 configured as described above, the nanofiber 301 can be manufactured and collected with high efficiency, and high production efficiency of the nanofiber 301 can be obtained. It becomes. In addition, it is possible to reduce the wire diameter of the manufactured nanofibers, and it is possible to manufacture nanofibers having a uniform wire diameter over the entire manufactured nanofibers.

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

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

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

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

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

  In the above embodiment, the raw material liquid 300 is caused to flow out using centrifugal force, but the present invention is not limited to this. For example, as shown in FIG. 5, the raw material liquid 300 may be caused to flow out from the outflow hole 216 by the pressure applied to the raw material liquid 300, or may be dropped due to gravity. Specifically, the nanofiber manufacturing apparatus 100 has a rectangular parallelepiped wind tunnel body 209 that is open at both ends, and an outflow body that is provided on one wall surface of the wind tunnel body 209 and a plurality of conical protrusions 220 are provided in a matrix. 211, an outflow hole 216 provided at the tip of the projecting portion 220, a gas flow generating means 203 provided also at one end opening of the wind tunnel body 209, and a charging electrode 221 disposed on the facing surface of the wind tunnel body 209. A charging electrode 221 arranged on the windward side than the outflow hole 216 located on the most windward side of the gas flow generated by the gas flow generating means 203, and the distance between the opening end of the outflow hole 216 and the charging electrode 221 is The outflow holes 216 may be arranged to be equal.

  Moreover, the outflow body 211 may have a shape as shown in FIG. The outflow body 211 shown in the figure does not include a hole vicinity portion 218 that is closer to the charging electrode 221 than a portion other than the hole vicinity portion 218 of the outflow body 211. The protruding portion of the outflow body 211 has a circular arc so that the distance from the charging electrode 221 is equal, and an outflow hole 216 is provided in the circular arc portion.

  Moreover, the outflow body 211 may have a shape and an arrangement as shown in FIG. The outflow body 211 shown in the figure has a tapered shape that gradually increases in diameter toward the collecting means 110, and the spreading angle is β.

  The charging electrode 221 has an annular shape with a rectangular cross section, and the distances L2 and L3 between the charging electrode 221 and the opening end of the outflow hole 216 are substantially the same. Here, L2 = L3 is best, but the same effect can be obtained even if L2 and L3 are substantially the same. If L3 × 0.8 <L2 <L3 × 1.2, the uniformity of the charge induced near the open end of the outflow hole 216 is acceptable. That is, if the effluent body 211 and the charging electrode 221 are arranged so that L3 × 0.8 <L2 <L3 × 1.2, the nanofiber manufactured based on the nanofiber manufacturing apparatus 100 having the configuration. The quality variation 301 is within an allowable range. In addition, the charging electrode 221 is disposed on the windward side of the outflow hole 216 located on the furthest upside of the gas flow generated by the gas flow generating unit 203. Specifically, when L2 and L3 are about 200 mm and the diameter of the effluent 211 is 60 mm, the angle β can be set to about 10 degrees. When the angle β is increased, L2 and L3 can be shortened, and the discharge means 200 can be made compact.

  In addition, the diameter of the charging electrode can prevent adhesion of the generated nanofiber by adopting the form of the present invention, and even with a small diameter, there is a merit that it is difficult to adhere, The distance between the charging electrode 221 and the hole vicinity portion 218 is shortened, and the electric field strength can be kept large even if the voltage applied between them is lower than the conventional voltage, and the cost rating is reduced by lowering the voltage rating of the power source. Can also be planned.

  The present invention can be applied to the production of nanofibers by electrospinning (charge-induced spinning), and the production of nonwoven fabrics on which the nanofibers are deposited.

It is sectional drawing which shows typically the nanofiber manufacturing apparatus which is embodiment of this invention from the front. It is sectional drawing which shows typically the nanofiber manufacturing apparatus which is embodiment of this invention from the upper surface. It is sectional drawing which shows a discharge | release means. It is a perspective view which shows discharge | release means. It is sectional drawing which shows another aspect of the discharge | release means. It is sectional drawing which shows another aspect of an outflow body. It is sectional drawing which shows the other aspect of an outflow body, and the other aspect of a charging electrode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Nanofiber manufacturing apparatus 101 Deposited member 102 Suction means 103 Hood 104 Transfer means 105 Blower 106 Solvent recovery apparatus 110 Collecting means 111 Supply means 120 Attracting means 121 Attracting electrode 122 Attracting power source 200 Discharge means 201 Outflow means 202 Charging means 203 Gas flow Generating means 204 Gas flow control means 205 Heating means 206 Guide body 209 Wind tunnel body 211 Outflow body 212 Rotating shaft body 213 Motor 215 Bearing 216 Outflow hole 217 Supply path 218 Near hole portion 219 Base 220 Protruding portion 221 Charging electrode 222 Charging power source 223 Grounding Means 224 Liquid receiving portion 225 Recess 228 Supply port 240 Diffusion means 300 Raw material liquid 301 Nanofiber

Claims (7)

A nanofiber manufacturing apparatus for manufacturing nanofibers by electrically stretching a raw material liquid in a space,
An outflow body having a plurality of outflow holes for flowing the raw material liquid into the space;
A supply path for supplying the raw material liquid to the inside of the effluent,
A portion that receives the raw material liquid discharged from the supply path on the inner periphery of the outflow body, and a liquid receiving portion that receives the raw material liquid on a surface that obliquely intersects the discharge direction of the raw material liquid;
A charging electrode that is disposed at a predetermined interval from the effluent, and to which a predetermined voltage is applied to the effluent;
A charging power source for setting a predetermined voltage between the outflow body and the charging electrode;
Gas flow generating means for generating a gas flow for transporting nanofibers produced from the raw material liquid flowing out from the effluent,
The outflow body is rotated while maintaining the distance relationship between the outflow hole and the charging electrode,
The charging electrode is arranged on the windward side of the gas flow generated by the gas flow generating means than the outflow hole,
The nanofiber manufacturing apparatus in which the opening end of the outflow hole is arranged so that the distance between the opening end of the outflow hole and the charging electrode is equal to each other. The outflow body has a hole vicinity portion that forms the outflow hole,
The nanofiber manufacturing apparatus according to claim 1, wherein the hole vicinity portion is closer to the charging electrode than a portion other than the hole vicinity portion of the outflow body. The outflow holes are arranged at a plurality of locations in a state of opening radially on the circumferential surface of the cylinder, and are also arranged in the axial direction of the cylinder,
The charging electrode is annular,
The nanofiber manufacturing apparatus according to claim 1, wherein the gas flow generating means is arranged so that a gas flow flows in a space surrounded by the charging electrode. further,
The nanofiber manufacturing apparatus according to claim 3, further comprising a driving unit that rotates the outflow body in a state where a distance relationship between the outflow hole and the charging electrode is maintained. The outflow hole is arranged in a direction in which the raw material liquid flows from the liquid receiving part, and is arranged in a recess in which a liquid reservoir of the raw material liquid is formed,
The nanofiber manufacturing apparatus according to claim 1, wherein the supply path includes a plurality of supply ports that discharge the raw material liquid to the plurality of liquid receiving units, respectively. further,
A collection means for collecting nanofibers produced in space;
The nanofiber manufacturing apparatus according to claim 1, further comprising an attracting unit that attracts the nanofiber to the collecting unit. A nanofiber manufacturing method for manufacturing a nanofiber by electrically stretching a raw material liquid in a space,
The raw material liquid is discharged from the supply path to the inside of the outflow body having a plurality of outflow holes, and the raw material liquid discharged from the liquid receiving portion having a surface obliquely intersecting with the discharge direction of the raw material liquid is received. A raw material liquid supply step of supplying the raw material liquid to the effluent,
An outflow step for flowing the raw material liquid into the space from the outflow body;
A gas flow generating step for generating a gas flow for transporting nanofibers produced from the raw material liquid flowing out from the effluent by a gas flow generating means;
A charging step of charging a raw material liquid by applying a predetermined voltage to the outflow body to a charging electrode disposed on the windward side of the gas flow from the outflow hole with a predetermined distance from the outflow body. ,
The outflow body is rotated while maintaining the distance relationship between the outflow hole and the charging electrode,
In the outflow step, the nanofiber manufacturing method of causing the raw material liquid to flow out from the open end of the outflow hole having the same distance from the charging electrode.

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