JP2011140725A - Apparatus for producing nanofiber and method for producing nanofiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce nanofibers having high quality, while maintaining high production efficiency. <P>SOLUTION: The apparatus for producing the nanofibers includes: an outflow member 211 having a circular flange portion 232; a charged electrode 221 arranged apart from the outflow member 211 at a prescribed distance; and a charging electric source 222 for applying a prescribed voltage between the outflow member 211 and the charged electrode 221, wherein the flange portion 232 comprises radially disposed outflow holes 216 for flowing out a raw material liquid 300 flowing in the flange portion 232 into a space; a tip portion 116 in which openings formed at the tips of the outflow holes 216 are arranged side-by-side; and two side portions 117 disposed so that the distance between the side portions is gradually expanded from the tip end portion 116 to the center portion, and extended from the tip end portion 116 so to nip the outflow holes 216. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

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

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

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

  The electrostatic stretching phenomenon will be described more specifically as follows. That is, the raw material liquid that has been charged and discharged into the space gradually evaporates the solvent while flying through the space. As a result, the volume of the raw material liquid in flight gradually decreases, but the charge imparted to the raw material liquid remains in the raw material liquid. As a result, the charge density of the raw material liquid in flight through the space gradually increases. Since the solvent continues to evaporate, the charge density of the raw material liquid further increases, and when the repulsive Coulomb force generated in the raw material liquid exceeds the surface tension of the raw material liquid, the raw material liquid explodes. The phenomenon that the film is stretched linearly occurs. This is the electrostatic stretching phenomenon. This electrostatic stretching phenomenon occurs geometrically in the space one after another, so that nanofibers made of a resin having a diameter of submicron order are manufactured.

  Improvement of production efficiency can be cited as an exclusive problem of an apparatus for producing nanofibers using the electrostatic stretching phenomenon as described above. For example, it may be possible to improve the production efficiency of nanofibers by arranging thin cylindrical nozzles that flow the raw material liquid into the space in a matrix, increasing the amount of nanofibers generated per unit area per unit time . However, in order to increase the amount of nanofibers generated per unit area, it is only necessary to narrow the nozzle arrangement interval. However, if the interval is narrowed, there is a problem with the nanofibers that are generated due to electric field interference between adjacent nozzles. appear. Therefore, in order to solve the problem, the invention described in Patent Document 1 prevents the electric field interference by disposing a separator in a lattice shape between nozzles and applying an AC voltage to the separator.

  In addition, as in the invention described in Patent Document 2, there is also an apparatus in which a large number of holes are provided radially on the side surface of a cylindrical outflow body, and the raw material liquid flows out into the space by rotating the outflow body around its axis. Proposed. In the present invention, by arranging the opening of the hole on the smooth curved surface (circumferential surface), it is possible to suppress the electric field interference without providing the separator, and it is possible to provide the openings densely.

JP 2002-201559 A JP 2008-150769 A

  However, in the invention of Patent Document 1, since it is necessary to provide a separator between the nozzles, the interval between the nozzles is widened accordingly, resulting in a decrease in production efficiency. Further, since the nozzle is surrounded by the separator, there is a concern that the charged vapor is likely to stagnate in the enclosed space and adversely affect the manufactured nanofiber. Moreover, it is difficult to make the pressure of the raw material liquid supplied to each nozzle uniform, and it is considered that unevenness occurs in the quality of the manufactured nanofibers.

  Furthermore, the present inventors have found that even if a separator is provided, ion wind is generated from the outer peripheral wall of the nozzle and the like, and the ion wind is adversely affected on the manufactured nanofiber.

  Here, the ion wind is considered to be generated by the following phenomenon. That is, when charge is accumulated in a portion having the outer peripheral wall surface, air existing around the portion is ionized. The ionized air is repelled by the charge on the wall surface and jumps out, thereby generating an ion wind that is a flow of air containing ions. In particular, it has been found that ion wind is likely to be generated at a specific portion of the shape of the outer peripheral wall, such as the tip of a protrusion or the tip of a corner.

  In addition, when the ion wind intersects with the raw material liquid that is flying in the space, it is manufactured by disturbing the flight path of the raw material liquid and the nanofiber being manufactured, or adversely affecting the electric resistance state of the raw material liquid. The quality of the nanofiber was degraded. It also led to a decrease in nanofiber production efficiency.

  On the other hand, in the invention described in Patent Document 2, since the openings are arranged on a smooth curved surface (circumferential surface), the charge for charging the raw material liquid is not easily collected in the opening, and the raw material liquid cannot be strongly charged. I came to find. If the raw material liquid cannot be strongly charged, it becomes difficult to produce high-quality nanofibers, and the production amount of nanofibers cannot be increased.

  The present invention is based on the above-mentioned problems and knowledge, and suppresses electric field interference to maintain a high production amount of nanofibers per unit area per unit time, and suppresses the influence of ion wind to suppress nanofibers. It aims at providing the nanofiber manufacturing apparatus and nanofiber manufacturing method which aim at the improvement and uniformization of the quality of the fiber.

  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. An outflow body including an annular flange portion that circulates, a charging electrode arranged at a predetermined interval from the outflow body, and a charging power source that applies a predetermined voltage between the outflow body and the charging electrode. Provided, the flange portion causes the raw material liquid flowing inward to flow out into the space, and an outflow hole provided in a radial direction, and a distal end portion in which an opening which is the distal end of the outflow hole is arranged side by side, It is characterized by comprising two side surface portions that are arranged so that the distance from the front end portion gradually increases toward the center, and that extend from the front end portion so as to sandwich the outflow hole.

  As a result, the openings of the outflow holes arranged radially at a predetermined interval are in a state in which the gap between the adjacent openings is completely filled with the tip, so that electric field interference is unlikely to occur. . Therefore, the interval between the openings through which the raw material liquid flows can be reduced as much as possible, and the production amount of nanofibers per unit area can be increased. In addition, the flange portion has the narrowest tip portion and has a side surface portion that gradually spreads from the opening toward the center, so even if ion wind is generated from the side surface portion, It has a structure that is difficult to fly in a direction that adversely affects the manufactured nanofibers. Furthermore, since the side surface portion is a surface that extends widely in an annular shape, ion wind is unlikely to occur. Therefore, the effluent can suppress the influence of the ionic wind on the nanofiber. Furthermore, since the tip portion where the opening is placed is arranged in a state of protruding from the cylindrical portion of the outflow body over the entire circumference in the radial direction, it is easy to concentrate the charge on the tip portion, and the tip portion is provided It becomes possible to give a high-density electric charge to the raw material liquid flowing out from the opening.

  It is preferable that the said front-end | tip part is an annular surface which has a width | variety wider than the diameter of the said opening part arrange | positioned at the said front-end | tip part in an axial direction.

  According to this, it is possible to sufficiently hold the liquid pool generated around the opening (see the section of the embodiment for the liquid pool) by the tip portion. Then, the raw material liquid flows out thinly from the liquid pool into the space, and an electrostatic stretching phenomenon occurs from there. As described above, since the raw material liquid covers the opening, the generation of ion wind can be suppressed.

  Furthermore, it is preferable to include a collecting means for collecting the nanofibers manufactured in the space and an attracting means for attracting the nanofibers to the collecting means.

  This makes it possible to manufacture functional materials and the like by limiting the targets on which the manufactured nanofibers are deposited.

  In order to achieve the above object, a nanofiber manufacturing method according to the present invention is a nanofiber manufacturing method for manufacturing a nanofiber by electrically stretching a raw material liquid in a space, and the raw material is formed inward. An outflow body comprising a cylindrical tube portion through which a liquid flows and a flange portion protruding radially from the tube portion over the entire circumference, and the raw material liquid flowing inward is caused to flow into the space, and the radial direction An outflow hole provided in a front end, a front end portion in which an opening which is a front end of the outflow hole is arranged, and an outflow hole disposed so that a mutual interval gradually increases from the front end portion toward a central direction. An outflow step of allowing the raw material liquid to flow out from the outflow body including the flange portion, the charging electrode being arranged at a predetermined interval from the outflow body. And the effluent It is characterized in that it comprises a charging step of applying a predetermined voltage between.

  As a result, the openings of the outflow holes arranged radially at a predetermined interval are in a state in which the gap between the adjacent openings is completely filled with the tip, so that electric field interference is unlikely to occur. . Therefore, the interval between the openings through which the raw material liquid flows can be reduced as much as possible, and the production amount of nanofibers per unit area can be increased. In addition, the flange portion has the narrowest tip portion and has a side surface portion that gradually spreads from the opening toward the center, so even if ion wind is generated from the side surface portion, It has a structure that is difficult to fly in a direction that adversely affects the manufactured nanofibers. Furthermore, since the side surface portion is a surface that extends widely in an annular shape, ion wind is unlikely to occur. Therefore, the effluent can suppress the influence of the ionic wind on the nanofiber. Furthermore, since the tip portion where the opening is placed is arranged in a state of protruding from the cylindrical portion of the outflow body over the entire circumference in the radial direction, it is easy to concentrate the charge on the tip portion, and the tip portion is provided It becomes possible to give a high-density electric charge to the raw material liquid flowing out from the opening.

  According to the present invention, it is possible to improve the production efficiency of the nanofiber and improve the quality of the manufactured nanofiber.

It is a top view which shows a nanofiber manufacturing apparatus from a front part typically notching. It is a top view which cuts out a part of nanofiber manufacturing apparatus typically and shows it from the upper surface. It is a top view shown from the front which cuts and shows the discharge | release means. It is a perspective view which shows discharge | release means. It is a figure which shows an outflow body, (a) is a top view which shows an external appearance from the front, (b) is a top view which cuts out a part and shows from the front. It is a perspective view which shows typically the formation state of a liquid pool. It is a perspective view which shows the variation of the shape of a front-end | tip part. It is a top view which shows the cross section of the outflow body which flows out a raw material liquid with a pressure from the front. It is a top view which shows other embodiment of an outflow body from the front. It is a top view which shows other embodiment of an outflow body from the front.

(Embodiment 1)
Next, a nanofiber manufacturing apparatus and a nanofiber manufacturing method according to the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view schematically showing a nanofiber manufacturing apparatus from the front with a part cut away.

  FIG. 2 is a plan view schematically showing the nanofiber manufacturing apparatus from the top with a part cut away.

  As shown in these drawings, the nanofiber manufacturing apparatus 100 includes a discharge unit 200, a collection unit 110, and an attracting unit 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 plan view from the front showing the discharge means cut away.

  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. In addition, the nanofiber manufacturing apparatus 100 of the present invention can be realized by the emitting means 200 alone described in the present embodiment.

  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 charges to the grounded outflow body 211 (which will be described later as a constituent member of the outflow means 201) 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. Moreover, as shown in FIGS. 1-4, the cross section of the charging electrode 221 is circular. 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. .

  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.

  In addition, the charging electrode 221 may not be disposed around the outflow body 211. For example, an attracting electrode 121 described later may function as the charging electrode 221.

  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 source 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 connected to the outflow body 211 and the motor 213 as a drive source from the outflow body 211. It is preferable that a simple structure can be adopted.

  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 source. The rotating shaft body 212 is rotatably supported by a support body (not shown) via a bearing 215.

  5A and 5B are views showing the outflow body, wherein FIG. 5A is a plan view showing the appearance from the front, and FIG. 5B is a plan view showing the cross section from the front.

  The outflow body 211 is a member for allowing the raw material liquid 300 to flow out into the space, and includes a cylindrical portion 231 and a flange portion 232 as shown in FIG. The outflow body 211 also functions as an electrode for supplying electric charge to the raw material liquid 300 that flows out, and at least a part of the portion in contact with the raw material liquid 300 is formed of a conductive member. In the case of the present embodiment, the entire outflow body 211 is made of metal. In addition, if the kind of metal is provided with electroconductivity, it will not specifically limit, Arbitrary materials, such as brass and stainless steel, can be selected.

  The cylindrical portion 231 is a cylindrical member through which the raw material liquid 300 flows and is a portion that becomes the body of the outflow body 211. In the case of the present embodiment, the outflow body 211 causes the raw material liquid 300 to flow out by a centrifugal force due to rotation, and the cylindrical portion 231 also functions as a rotating shaft body of the outflow body 211.

  The flange portion 232 is a member in which an outflow hole 216 for allowing the raw material liquid 300 passing through the cylindrical portion 231 to flow out into the space is provided in a radial direction, and a distal end at which an opening 233 that is the front end of the outflow hole 216 is arranged. Part 116 and two side parts 117 that are arranged so that the distance from the tip part 116 gradually increases toward the center and that extends from the tip part 116 so as to sandwich the outflow hole 216.

  In the case of the present embodiment, the flange portion 232 is a disc having a triangular cross section whose thickness gradually decreases toward the outside. Specifically, the diameter of the flange portion 232 is preferably adopted from a range of 10 mm or more and 300 mm or less. If it is too large, a large vibration occurs if the weight balance is slightly deviated, for example, the rotational axis of the effluent 211 is eccentric, and a structure that firmly supports the effluent 211 is required to suppress the vibration. Because it becomes. 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.

  In the case of the present embodiment, the outflow holes 216 are arranged so that the openings 233 are arranged on the circumference in the same plane.

  The hole length and hole diameter of the outflow hole 216 are not particularly limited, and a shape suitable for the viscosity of the raw material liquid 300 may be selected. Specifically, the hole length is preferably selected from a range of 1 mm or more and 5 mm or less. The hole diameter is preferably selected from a range of 0.1 mm or more and 2 mm or less. Further, the shape of the outflow hole 216 is not limited to a cylindrical shape, and an arbitrary shape can be selected. In particular, the shape of the opening 233 is not limited to a circular shape, and may be a polygonal shape such as a triangle or a quadrangle, or a shape having a protruding portion such as a star shape.

  Note that the portion where the opening 233 is disposed (tip portion 116) has a shape in which the band is annular so that the surface faces in the radial direction. In the shape of this portion, the opening 233 may be arranged in a zigzag manner, or may be arranged so as to draw a wave such as a sine curve.

  The front end portion 116 is a portion of the flange portion 232 where the opening portion 233 of the outflow hole 216 is disposed, and is a portion that connects between the opening portions 233 disposed at a predetermined interval with a smooth surface. In the case of the present embodiment, the distal end portion 116 includes an annular curved surface arranged so that the surface of the elongated rectangular plane faces the radial direction, and the width (axial direction) is larger than the diameter of the corresponding opening 233. Is also set to be wide. In the case of the present embodiment, the distal end portion 116 has an annular shape.

  In addition, the outflow body 211 which concerns on this invention should just be provided with the flange part 232, and the cylinder part 231 is not an essential component. That is, the outflow body 211 may consist only of the flange portion 232, and in this case, the raw material liquid 300 is supplied directly from the supply path 217 to the inside of the flange portion 232. Moreover, the raw material liquid 300 may be supplied in a pressurized state by a pump or the like.

  As shown in FIG. 6, the presence of the smoothly curved tip 116 around the entire periphery of the opening 233 causes a liquid pool 303 to be generated around the opening 233. This liquid reservoir 303 is called a Taylor cone, and is considered to be generated by the viscosity of the raw material liquid 300 and has a conical shape with a circular bottom surface larger than the opening 233. The liquid reservoir 303 adheres to the front end portion 116 of the outflow body 211 so as to cover the opening 233. Then, the raw material liquid 300 flows out from the conical liquid pool 303 into the space. Thereby, since the opening part 233 does not contact air directly, it becomes possible to suppress the ionic wind generated from the opening part 233.

  The tip portion 116 is not limited to the one having a smooth curved surface, and the liquid pool 303 may be generated even if it is not a surface facing the radial direction. For example, as shown to Fig.7 (a), the front-end | tip part 116 may be provided with a curved surface, and as shown in FIG.7 (b), it may be provided with two planes with which the edge part was put together.

  As described above, the front end portion 116 connects a plurality of openings 233 with a smooth surface (in FIG. 7B, the two ends are connected as described above). It is possible to suppress the electric field interference that occurs when the nozzles are arranged. In addition, ion wind generated in a region between the opening 233 and the opening 233 can be suppressed. Accordingly, even if the openings 233 are arranged in a narrowed state, the nanofibers 301 can be manufactured satisfactorily, and therefore the production amount of the nanofibers 301 per unit time and unit area can be improved. Become.

  In addition, since the liquid reservoir 303 can be held in a good state by the distal end portion 116, it is considered that the generation of ion wind can be suppressed and the quality of the nanofiber 301 can be improved and the production efficiency can be improved.

  As shown in FIG. 5, the side surface portion 117 is two surfaces disposed so as to sandwich the outflow hole 216, and is a portion of the flange portion 232 that continuously extends from the tip end portion 116. The side surface portion 117 is provided so as to protrude outward from the cylindrical portion 231, and is provided so as to sandwich all the outflow holes 216 between the two side surface portions 117. Further, the side surface portions 117 are arranged so that the distance between the side surface portions 117 increases as the distance from the front end portion 116 increases.

  In addition, as shown to Fig.7 (a) and FIG.7 (b), the boundary of the front-end | tip part 116 and the side part 117 is ambiguous. It is desirable that the side surface portion 117 and the tip portion 116 have a smooth surface as a whole and have a shape that suppresses the generation of ion wind without providing a peculiar portion as much as possible (excluding the opening portion 233).

  Since the outflow body 211 includes the flange portion 232, it is possible to suppress the generation of ion wind and manufacture the nanofiber 301 in a stable state. Further, since the side surface portion 117 is arranged so as to become gradually narrower toward the front end portion 116, the charge can be easily concentrated on the front end portion 116, and the charge can be efficiently supplied to the raw material liquid 300.

  In the case of the present embodiment, as shown in FIG. 3, 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. The outflow body 211 is rotatably supported by a bearing 215. Moreover, the flange part 232 is provided with the recessed part 255 in the internal shape, as shown in FIG. The recess 255 is recessed in the direction of the centrifugal force generated when the outflow body 211 rotates, and functions as a tank in which the raw material liquid 300 accumulates when the outflow body 211 is rotating. An outflow hole 216 is provided at the distal end of the concave portion 255 in the centrifugal force direction. Thus, by providing the recessed part 255 in a flange part, the raw material liquid 300 can be equally made to flow out to space.

  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 generated by its own rotation, but is also stationary as shown in FIG. 8, and the raw material liquid stored in the cylindrical portion 231. By applying force A to the piston 235 disposed inside the cylindrical portion 231, 300 may be allowed to flow out only by the pressure of the raw material liquid 300. Moreover, while giving the force given to piston 235 with air, the outflow body 211 may be rotated and the raw material liquid 300 may be flowed out by a pressure and a centrifugal force. 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. Alternatively, the raw material liquid 300 may be supplied to the outflow body 211 by a supply pressure (supply pump), and the raw material liquid 300 may be discharged by the supply pressure.

  Next, a rotation mechanism that rotates the outflow body 211 will be described.

  As shown in FIG. 3, 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 flows out from the other end of the outflow body 211. It is a rod-shaped body that is inserted into the body 211 and joined to the closed portion and one end portion of the outflow body 211. 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 outflow body 211 via the rotary shaft body 212 in order to cause the raw material liquid 300 to flow out from the outflow hole 216 by centrifugal force.

  Next, although not essential for the present invention, the gas flow generating means 203 for controlling the flight path of the raw material liquid 300 will be described.

  As shown in FIG. 3, the gas flow generating 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 a predetermined direction. 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. In the case of the present embodiment, the gas flow generation means 203 can generate 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.

  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 means 204 has a function of controlling the gas flow so that the gas flow generated by the gas flow generation means 203 does not directly hit the opening 233 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 heating unit 205 is a heating source that heats the gas constituting the gas flow generated by the gas flow generation unit 203. In the case of the present embodiment, the heating means 205 is an annular heater disposed inside the wind tunnel body 209, and can heat the gas passing through the heating means 205. By heating the gas flow by the heating means 205, the raw material liquid 300 flowing out into the space is accelerated in evaporation, and nanofibers can be efficiently manufactured.

  Next, the collecting means 110 and the attracting means 120 included in the nanofiber manufacturing apparatus 100 will be described.

  As shown in FIGS. 1 and 2, the collecting unit 110 is a device for collecting the nanofibers 301 emitted from the emitting unit 200, and includes a deposition target member 101, a transfer unit 104, and a supply unit 111. I have.

  The member to be deposited 101 is a member on which the nanofibers 301 that are manufactured and fly by the 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.

  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 attracting a gas flow and a method of attracting with an electric field, 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 effluent 211 toward the collecting means 110 (gas flow generating step). On the other hand, the gas flow is sucked by the suction means 102. In the above state, the air volume was adjusted to 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 end of the supply path 217 is stored in a recess 255 provided inside the outflow body 211.

  Here, the resin constituting the nanofiber 301, and the solute dissolved or dispersed in the raw material liquid 300 is 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 Coalesce, polycarbonate, polyarylate, polyester carbonate, polyamide, aramid, polyimide, polycaprolactone, polylactic acid, polyglycolic acid Collagen, polyhydroxybutyric acid, polyvinyl acetate, polypeptides and the like, and polymeric materials such as copolymers thereof can be exemplified. Moreover, the kind selected from the above may be used, and a plurality of kinds may be mixed. In addition, the above is an illustration and this invention is not limited to the said resin.

  Examples of the solvent used for the raw material liquid 300 include volatile organic solvents. Specific examples are methanol, ethanol, 1-propanol, 2-propanol, hexafluoroisopropanol, tetraethylene glycol, triethylene glycol, dibenzyl alcohol, 1,3-dioxolane, 1,4-dioxane, methyl ethyl ketone, methyl isobutyl. Ketone, methyl-n-hexyl ketone, methyl-n-propyl ketone, diisopropyl ketone, diisobutyl ketone, acetone, hexafluoroacetone, phenol, formic acid, methyl formate, ethyl formate, propyl formate, methyl benzoate, ethyl benzoate, benzoate Propyl acid, methyl acetate, ethyl acetate, propyl acetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, methyl chloride, ethyl chloride, methylene chloride, chloroform, o-chloroto Ene, p-chlorotoluene, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane, dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethyl bromide, propyl bromide, acetic acid, benzene, Toluene, hexane, cyclohexane, cyclohexanone, cyclopentane, o-xylene, p-xylene, m-xylene, acetonitrile, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, pyridine, water, etc. Can be shown. Moreover, the kind selected from the above may be used, and a plurality of kinds may be mixed. In addition, the above is an illustration and the raw material liquid 300 used for this invention is not limited to employ | adopting the said solvent.

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

  The mixing ratio of the solvent and the solute in the raw material liquid 300 varies depending on the type of solvent selected and the type of solute, but the amount of solvent is preferably between about 60 wt% and 98 wt%. The solute is preferably 5 to 30% by weight.

  In the case of this embodiment, 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 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. As a result, charges concentrate on the tip portion 116, and the charges are 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 on the front end portion 116 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).

  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, the outflow body 211 having an outer diameter of the flange portion 232 of 60 mm was used. Twenty-four outflow holes 216 provided at the distal end of the flange portion 232 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 has its flight direction changed by the gas flow and is guided by 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 member 101 to be deposited.

  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, since the raw material liquid 300 flows out in a strong charged state (high charge density), an electrostatic stretching phenomenon easily occurs, and most of the raw material liquid 300 that flows out changes to the nanofibers 301. In addition, since the raw material liquid 300 flows out in a 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.

  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.

  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 manufacture high-quality nanofibers 301 at a high density without being affected by ion wind or the like.

  In the above embodiment, the outflow body 211 is provided with one flange portion 232 extending in the radial direction, but the present invention is not limited to this. For example, as shown in FIG. 9, the outflow body 211 may include a plurality of flange portions 232 arranged in the direction of the rotation axis. Further, as shown in FIG. 10, the flange portion 232 may have a shape protruding in a direction inclined in the radial direction.

The present invention is not limited to the above embodiment. For example, another embodiment realized by arbitrarily combining the components described in this specification may be the present invention. In addition, the present invention also includes modifications obtained by making various modifications conceivable by those skilled in the art without departing from the gist of the present invention, that is, the meanings indicated in the claims. included. For example, the drawing shows the collecting means in the left-right direction with respect to the discharging means, but this is merely an example of an embodiment that can realize the present invention. That is, in the claims, there is no wording that limits the direction of discharging the raw material liquid and the direction of collecting the manufactured nanofibers, but this does not indicate the intention to limit the description to the drawings. In other words, the direction is not an essential element for the present invention. Therefore, the direction in which the raw material liquid is discharged is within the scope of the present invention regardless of the global direction, and the direction in which the nanofibers are collected is within the scope of the present invention regardless of the global direction. Further, the positional relationship between the discharging means and the collecting means is not an essential element of the present invention. Therefore, even if the discharge means is disposed above the collection means, the discharge means is disposed below the collection means, or the line that virtually connects the discharge means and the collection means intersects in the vertical direction. It doesn't matter. In this sense, the present invention can be realized in a weightless space without the upper and lower concepts.

  The present invention can be used for manufacturing a nonwoven fabric using nanofibers, particularly for manufacturing a thick nonwoven fabric.

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 116 Tip part 117 Side face part 120 Inducing means 121 Inviting electrode 122 Inviting power source 200 Ejecting means 201 Outflow means 202 Charging means 203 Gas flow generating means 204 Gas flow control means 205 Heating means 209 Wind tunnel body 211 Outflow body 212 Rotating shaft body 213 Motor 215 Bearing 216 Outflow hole 217 Supply path 221 Charging electrode 222 Charging power supply 223 Grounding means 231 Tube portion 232 Flange Portion 233 Opening 235 Piston 255 Concave portion 300 Raw material liquid 301 Nanofiber

Claims (6)

A nanofiber manufacturing apparatus for manufacturing nanofibers by electrically stretching a raw material liquid in a space,
An outflow body provided with an annular flange portion through which the raw material liquid circulates;
A charging electrode disposed at a predetermined interval from the effluent body;
A charging power source for applying a predetermined voltage between the effluent and the charging electrode;
The flange portion is
The outflow hole provided in the radial direction, the raw material liquid flowing through the inside flows out into the space,
A tip portion arranged side by side with an opening that is the tip of the outflow hole;
An apparatus for producing nanofibers, comprising: two side parts that are arranged so that a mutual interval gradually increases from the tip part toward the center, and extend from the tip part so as to sandwich the outflow hole. 2. The nanofiber manufacturing apparatus according to claim 1, wherein the distal end portion includes an annular surface having a width in the axial direction that is wider than a diameter of the opening disposed at the distal end portion.   The nanofiber manufacturing apparatus according to claim 1, wherein the tip portion is sharpened in a radial direction so as to form an annular ridgeline. 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. further,
The nanofiber manufacturing apparatus according to claim 1, further comprising a drive source that applies a rotational force that rotates about an axis to the outflow body. A nanofiber manufacturing method for manufacturing a nanofiber by electrically stretching a raw material liquid in a space,
An outflow body provided with an annular flange portion through which the raw material liquid flows in, an outflow hole provided in the radial direction for flowing out the raw material liquid flowing inward into the space, and a tip of the outflow hole A front end portion where the openings are arranged side by side, and two side surfaces that are arranged so that a mutual interval gradually increases from the front end portion toward the center and extends from the front end portion so as to sandwich the outflow hole An outflow step of causing the raw material liquid to flow out from the outflow body comprising the flange portion,
A nanofiber manufacturing method, comprising: a charging electrode disposed at a predetermined interval from the effluent body; and a charging step of applying a predetermined voltage between the effluent body.

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