JP5364004B2 - Nanofiber manufacturing apparatus and nanofiber manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method for manufacturing nanofiber that achieves an efficient production of a high quality nanofiber. <P>SOLUTION: The nanofiber manufacturing device 100 manufacturing a nanofiber 301 by electrically stretching a raw liquid 300 in a space includes: an outflow body 115 having an outflow hole 118 which flows out the raw liquid 300 in a space and an outer surface part 116 where an opening part 119 is located at the tip of the outflow hole 118; a charged electrode 121 which is arranged in prescribed space with the outflow body 115; and a charging power supply 122 which adds a prescribed electric voltage between the outflow body 115 and the charged electrode 121. The outer surface part 116 has a prescribed wettability to the raw liquid 300 so as to obtain a Tailor cone regulation region 120 which regulates the size of the bottom of a Tailor cone 303 formed by the raw liquid 300 flown from the outflow hole 118. <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 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. Occur. 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 this invention, by arranging the opening of the hole on a smooth curved surface (circumferential surface), it is possible to suppress electric field interference without providing the separator, and it is possible to provide the opening 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.

  On the other hand, in the invention described in Patent Document 2, since the openings are arranged on the peripheral surface, the electric field interference between the adjacent openings is suppressed. Thereby, it is possible to shorten the space | interval of an opening part. However, since the opening through which the raw material liquid flows out is formed on the peripheral surface, the raw material liquid bleeds around the opening. As a result, the bottom surface of the cone-shaped Taylor cone, which is formed by the raw material liquid flowing out from the opening and tapers in the outflow direction, becomes unnecessarily large.

  The Taylor cone is formed by a balance of the surface tension of the raw material liquid, the pressure at which the raw material liquid flows out into the air, and the force due to the electric field that attracts the raw material liquid that has flowed out into the air toward the deposited film. It is a conical liquid pool.

  Here, the Taylor cone may be necessary for charge concentration. However, the present inventors have found that problems arise in the efficient production of high-quality nanofibers when the bottom surface of the Taylor cone becomes unnecessarily large.

  Specifically, as the bottom surface of the Taylor cone increases, the stagnation of the solution occurs near the bottom surface, and the area where the raw material liquid comes into contact with air increases. As a result, the raw material liquid is solidified, and the raw material liquid may be prevented from flowing into the space. Furthermore, there is a possibility that the quality of the fiber deteriorates due to the stagnation becoming droplets and falling onto the deposited film on which the nanofibers are deposited.

  The present invention is based on the above problems and knowledge, and an object of the present invention is to provide a nanofiber manufacturing apparatus and a nanofiber manufacturing method for efficient production of high-quality nanofibers.

  In order to achieve the above object, a nanofiber manufacturing apparatus according to the present invention is a nanofiber manufacturing apparatus that manufactures nanofibers by electrically stretching a raw material liquid in a space. An outflow body having an outflow hole to be discharged, an outflow body having an outer surface portion in which an opening that is a tip of the outflow hole is disposed, and a charging electrode disposed at a predetermined interval from the outflow body, A charging power source that applies a predetermined voltage between the outflow body and the charging electrode, and the outer surface portion has a predetermined wettability with respect to the raw material liquid, whereby the raw material flowing out from the outflow hole It has a Taylor cone regulation region that regulates the size of the bottom surface of the Taylor cone formed by the liquid.

  With this configuration, the size of the bottom surface of the Taylor cone formed by the raw material liquid flowing out from the outflow body is regulated to a predetermined size or less by the Taylor cone regulation region.

  Therefore, it becomes possible to form a tailor cone having a shape according to the characteristics of the raw material liquid, and as a result, it is possible to prevent solidification of the raw material liquid near the opening of the outflow hole and dripping of the raw material liquid onto the deposited film. it can. In addition, when there are a plurality of outflow holes, the shape of the Taylor cone at the opening of each of the plurality of outflow holes can be made uniform. That is, the nanofiber manufacturing apparatus according to the present invention realizes efficient production of high-quality nanofibers.

  Further, the Taylor cone regulation region is formed so as to surround the opening, and is formed so as to surround the first region having a wettability higher than the predetermined wettability, and the predetermined region. A second region having wettability may be included.

  With this configuration, the spread of the raw material liquid flowing out from the opening can be regulated at the boundary between the first region and the second region.

  Further, the Taylor cone regulation region may regulate the size of the bottom surface of the Taylor cone to be equal to or less than the predetermined size when the first region is not greater than a predetermined size.

  According to this configuration, by adjusting the size of the first region, an appropriate shape according to the characteristics of the raw material liquid, the installation environment of the nanofiber manufacturing apparatus, the type of nanofiber to be manufactured, and the like Can be formed.

  The outflow hole may cause the raw material liquid to flow out from the non-circular opening, and the first region may be a circular region formed so as to surround the non-circular opening.

  With this configuration, even if the opening is a non-circular shape such as a polygon, a Taylor cone having a stable bottom shape with a circular bottom surface can be formed. Thereby, the stable outflow of the raw material liquid from the non-circular opening is realized.

  In order to achieve the above object, a nanofiber manufacturing method according to the present invention is a nanofiber manufacturing method for manufacturing nanofibers by electrically stretching a raw material liquid in a space. An outflow body having an outflow hole for allowing outflow, and an outflow process for causing the raw material liquid to flow out from the outflow body having an outer surface portion in which an opening that is a tip of the outflow hole is disposed, and a predetermined distance from the outflow body A charging step in which a predetermined voltage is applied between the charging electrode and the effluent that are spaced apart from each other, and a Taylor cone regulation region that the outer surface portion has has a predetermined wettability with respect to the raw material liquid. And a Taylor cone regulating step for regulating the size of the bottom surface of the Taylor cone formed by the raw material liquid that flows out in the outflow step.

  Thereby, the size of the bottom surface of the Taylor cone formed by the raw material liquid flowing out from the outflow body can be restricted to a predetermined size or less.

  Therefore, the above-described solidification of the raw material liquid and dripping onto the deposited film can be prevented. In addition, when there are a plurality of outflow holes, the shape of the Taylor cone at the opening of each of the plurality of outflow holes can be made uniform. That is, efficient production of high-quality nanofibers is realized by the nanofiber manufacturing method according to the present invention.

  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 perspective view which shows the nanofiber manufacturing apparatus of embodiment. It is a perspective view which cuts and shows an outflow body. It is a perspective view which shows the outflow body seen from the outer surface part side. It is the figure which looked at the outer surface part from the lower part which shows the 1st example of a structure of a Taylor cone control area | region. It is the figure which looked at the outer surface part from the diagonally downward direction which shows the 1st example of a structure of a Taylor cone control area | region. It is a fragmentary sectional view of the outflow body near the opening which shows the 1st example of composition of a Taylor cone regulation field. It is the figure which looked at the outer surface part from the lower part which shows the 2nd example of a structure of a Taylor cone control area | region. It is the figure which looked at the outer surface part from the diagonally downward direction which shows the 2nd example of a structure of a Taylor cone control area | region. It is a fragmentary sectional view of the outflow body near an opening which shows the 2nd example of composition of a Taylor cone regulation field. It is the figure which looked at the outer surface part in which the rectangular opening part is arrange | positioned from the downward direction. It is the figure which looked at the outer surface part in which the rectangular opening part is arrange | positioned from diagonally downward. It is the figure which looked at the outer surface part provided with a curved surface from diagonally downward.

  A nanofiber manufacturing apparatus and a nanofiber manufacturing method according to embodiments of the present invention will be described with reference to the drawings.

  First, the basic configuration of the nanofiber manufacturing apparatus according to the embodiment will be described with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view showing a nanofiber manufacturing apparatus according to an embodiment.
As shown in FIG. 1, the nanofiber manufacturing apparatus 100 is an apparatus that manufactures nanofibers 301 by electrically stretching a raw material liquid 300 in a space, and includes an effluent body 115, a supply means 107, a charging device. An electrode 121, a charging power source 122, a collecting unit 128, an attracting unit 104, and a moving unit 129 are provided.

FIG. 2 is a perspective view showing the outflow body 115 by cutting it out.
The outflow body 115 is a member for causing the raw material liquid 300 to flow out into the space by the pressure of the raw material liquid 300 (which may include gravity), and includes an outflow hole 118, an outer surface portion 116, and a side surface portion 117. Furthermore, a storage tank 113 is provided. The outflow body 115 also functions as an electrode for supplying electric charge to the outflowing raw material liquid 300, 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 115 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 outflow holes 118 are holes through which the raw material liquid 300 flows out into the space, and a plurality of outflow holes 115 are provided in the outflow body 115. In addition, the opening 119 at the tip of each of the plurality of outflow holes 118 is arranged on the outer surface 116 in a one-dimensional manner at a predetermined interval.

  The hole length and hole diameter of the outflow hole 118 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 118 is not limited to a cylindrical shape, and an arbitrary shape can be selected. In particular, the shape of the opening 119 is not limited to a circular shape, and may be a non-circular shape such as a polygonal shape such as a triangle or a quadrangle, or a shape having a protruding portion such as a star shape.

  Further, the intervals at which the openings 119 are arranged may be all equally spaced. In addition, the interval between the openings 119 at the end of the outflow body 115 in the direction in which the openings 119 are arranged (X direction) is arbitrarily wider (narrower) than the distance between the openings 119 at the center of the outflow body 115. Can be determined. In the knowledge currently obtained, when the hole diameter of the opening part 119 is 0.3 mm, the pitch of the opening part 119 can be shortened to about 2.5 mm. In addition, it is possible to determine these hole diameters, pitches, etc. according to other conditions, such as the viscosity of the raw material liquid 300.

  Further, the openings 119 need not only be arranged on the same straight line, but also need only be arranged one-dimensionally. Here, the term “one-dimensional” refers to a state where the opening 119 is not lined up in the width direction of the rectangle when a marginal region where all the openings 119 are arranged is surrounded by a rectangle. The rectangular region where the opening 119 is disposed has a band shape. In this sense, the opening 119 may be arranged in a zigzag manner, or may be arranged so as to draw a wave such as a sine curve.

  Further, as shown in FIG. 2, the side surface portion 117 is disposed so as to become gradually narrower toward the outer surface portion 116. Therefore, charges can be easily concentrated on the outer surface portion 116, and charges can be efficiently supplied to the raw material liquid 300.

  As shown in FIG. 2, the storage tank 113 is a tank that is formed inside the outflow body 115 and stores the raw material liquid 300 supplied from the supply means 107 (see FIG. 1). The storage tank 113 is connected to a plurality of outflow holes 118, and supplies the raw material liquid 300 to the outflow holes 118 at the same time. That is, the storage tank 113 has a function of temporarily storing the raw material liquid 300 in the vicinity of the outflow holes 118 and supplying the raw material liquid 300 to the plurality of outflow holes 118 with an equal pressure.

  As shown in FIG. 1, the supply means 107 is a device that supplies the raw material liquid 300 to the effluent body 115, and includes a container 151 that stores a large amount of the raw material liquid 300, and a pump ( (Not shown) and a guide tube 114 for guiding the raw material liquid 300.

  The charging electrode 121 is disposed at a predetermined interval from the effluent body 115 and has a conductivity for inducing electric charge to the effluent body 115 when the charging electrode 121 is at a higher voltage or lower voltage than the effluent body 115. It is. In the case of the present embodiment, the charging electrode 121 also functions as an attracting means 104 for attracting the nanofiber 301, is disposed at a position facing the outer surface portion 116 of the outflow body 115, and is grounded. Therefore, when a positive voltage is applied to the efflux body 115, a negative charge is induced in the charging electrode 121, and when a negative voltage is applied to the efflux body 115, a positive charge is induced in the charging electrode 121. Is done.

  The charging power source 122 is a power source that can apply a high voltage to the outflow body 115. In general, the charging power source 122 is preferably a DC power source. When the charging power source 122 is a direct current power source, the voltage applied by the charging power source 122 to the charging electrode 121 is preferably set from a value in the range of 5 KV or more and 50 KV or less.

  As in the present embodiment, if one electrode of the charging power source 122 is set to the ground potential and the charging electrode 121 is grounded, the relatively large charging electrode 121 can be brought into the ground state, which contributes to improvement in safety. It becomes possible.

  Alternatively, a power source may be connected to the charging electrode 121 to maintain the charging electrode 121 at a high voltage, and the effluent 115 may be grounded to apply a charge to the raw material liquid 300. Further, the charging electrode 121 and the outflow body 115 may be in a connection state in which neither is grounded.

  Further, a high-voltage power supply having opposite polarities may be connected to the effluent body 115 and the charging electrode 121, respectively.

  The collecting means 128 is a member that deposits and collects the nanofibers 301 manufactured by the electrostatic stretching phenomenon. In the case of the present embodiment, the collecting means 128 is a sheet of tungsten that is a member that forms a capacitor that is an electronic device, and is supplied in a state of being wound around a roll 127.

  The collecting unit 128 is not limited to this. For example, the collecting means 128 may be made of a rigid plate-like member. Further, when only the deposit of the nanofiber 301 is used, the collecting means 128 having high releasability when the nanofiber 301 is peeled off may be used, for example, the surface of the collecting means 128 is coated with fluorine.

  The attracting means 104 is an apparatus for attracting the nanofiber 301 manufactured in the space to the collecting means 128. In the case of the present embodiment, the attracting means 104 is a metal plate that also functions as the charging electrode 121 and is disposed behind the collecting means 128. The attracting means 104 attracts the charged nanofiber 301 to the collecting means 128 by an electric field. That is, the attracting means 104 is an electrode for generating an electric field for attracting the charged nanofiber 301.

  The moving unit 129 is a device that relatively moves the outflow body 115 and the collecting unit 128. In the case of the present embodiment, the effluent body 115 is fixed and moves only the collecting means 128. Specifically, the moving unit 129 pulls out the long collecting unit 128 from the roll 127 while winding it, and conveys the collecting unit 128 together with the nanofibers 301 to be deposited.

  The moving means 129 may not only move the collecting means 128 but also move the effluent 115 relative to the collecting means 128. The moving means 129 moves the collecting means 128 in a certain direction. Arbitrary operation states, such as reciprocating the outflow body 115, can be exemplified. Further, although the collecting means 128 is moved in a direction orthogonal to the direction in which the openings 119 are arranged, the present invention is not limited to this, and the collecting means 128 is moved in the direction in which the openings 119 are arranged, and the effluent 115 is moved to the opening. You may make it reciprocate in the direction orthogonal to the arrangement direction of 119.

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. The above is an example,
The present invention is not limited to the above resin.

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

Furthermore, an 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. From the viewpoint of heat resistance and workability of the nanofiber 301 to be manufactured. 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%. Preferably the solute is 5-30%.

Next, details of the outer surface portion 116 in the embodiment will be described with reference to FIG.
FIG. 3 is a perspective view showing the outflow body 115 viewed from the outer surface portion 116 side.

  As shown in FIG. 3, the outer surface portion 116 is a portion of the outflow body 115 in which the opening portion 119 of the outflow hole 118 is disposed, and connects between the opening portions 119 disposed at predetermined intervals with a smooth surface. Part. In the case of the present embodiment, the outer surface portion 116 has an elongated rectangular plane on the surface, and the width thereof is set to be wider than the diameter of the opening 119.

  In addition, since the outer surface portion 116 having a flat surface exists over the entire periphery of the opening 119 as described above, each opening 119 has a hole diameter of the opening 119 formed by the flowing out raw material liquid 300. The Taylor cone 303, which is a pool of the raw material liquid 300 having the above circular bottom surface, is generated.

  As described above, the Taylor cone 303 is generated due to the surface tension of the raw material liquid 300 and has a conical shape having a circular bottom surface on the outer surface portion 116.

  Moreover, as shown in FIG. 3, the raw material liquid 300 flows out thinly into the space from the conical Taylor cone 303. Thereby, since the opening part 119 does not contact air directly, the ionic wind generated from the opening part 119 is suppressed.

  In addition, since the outer surface portion 116 connects a plurality of openings 119 with a surface, it is possible to suppress electric field interference. In addition, ion wind generated in a region between the opening 119 and the opening 119 can be suppressed. Therefore, even if it arrange | positions in the state which narrowed the space | interval of the opening part 119, the nanofiber 301 can be manufactured favorably.

  Here, the outer surface portion 116 in the present embodiment has a Taylor cone regulation region 120 that regulates the size of the bottom surface of the Taylor cone 303 by having a predetermined wettability with respect to the raw material liquid 300.

  This prevents the bottom surface of the Taylor cone 303 from becoming unnecessarily large. As a result, the amount of stagnation of the solution generated in the vicinity of the bottom surface is suppressed, and solidification of the raw material liquid 300 and dripping onto the deposited film are prevented.

  The Taylor cone regulation region 120 may be disposed so as to cover the entire outer surface portion 116, or may be disposed only on a part of the outer surface portion 116 including the periphery of each opening 119. Further, the predetermined wettability possessed by the Taylor cone regulation region 120 is wettability that suppresses the spread of the raw material liquid 300 by repelling the raw material liquid 300. For example, it is possible to prevent the raw material liquid 300 from getting wet and spreading by applying a fluorine coating to the metal surface forming the outer surface portion 116.

  Hereinafter, a configuration example of the Taylor cone regulation region 120 will be described with reference to FIGS. 4A to 6.

  4A to 4C are diagrams illustrating a first example of the configuration of the Taylor cone regulation region 120. FIG. Specifically, FIG. 4A is a view of the outer surface portion 116 as viewed from below, FIG. 4B is a view of the outer surface portion 116 as viewed from obliquely below, and FIG. 4C is a view of the outflow body 115 near the opening 119. It is a fragmentary sectional view.

  The Taylor cone regulation region 120 shown in FIGS. 4A to 4C includes a first region 120a and a second region 120b. The first region 120a has a wettability higher than the predetermined wettability and is formed so as to surround the opening 119. The second region 120b has the predetermined wettability and is formed so as to surround the first region 120a.

  In the first region 120a formed in this way, the first region 120a has higher wettability than the predetermined wettability of the second region 120b, so that wetting and spreading of the raw material liquid 300 is allowed. However, in the second region 120b, the second region 120b has the predetermined wettability, so that wetting spread is suppressed. As a result, as shown in FIGS. 4B and 4C, the size of the bottom surface of the Taylor cone 303 is regulated at the boundary between the first region 120a and the second region 120b.

  For example, when the raw material liquid 300 has water as a solvent, the first region 120a is coated with, for example, titanium oxide, and the second region 120b is coated with, for example, fluorine. Thereby, the raw material liquid 300 spreads out in the first region 120a, and the wetting and spreading can be stopped at the boundary between the first region 120a and the second region 120b.

  The second region 120b has a predetermined wettability such that the raw material liquid 300 flowing out from the opening 119 does not wet and spread, and the first region 120a has a wettability higher than the predetermined wettability. If it has, the presence or absence of active processing, such as coating of the material which improves or reduces the wettability, to the first region 120a and the second region 120b is not limited to any one.

  In the Taylor cone regulation region 120 configured as described above, the size of the bottom surface of the Taylor cone 303 can be changed by adjusting the size of the first region 120a.

  For example, when the raw material liquid 300 is relatively difficult to dry, such as when the solute contained in the raw material liquid 300 is polyurethane and the solvent is dimethylacetamide, the first region 120a is enlarged. The radius of the outer circle of 120a is set to a relatively large value. As a result, the bottom surface of the Taylor cone 303 is increased, the surface area of the Taylor cone 303 is increased, and appropriate drying of the raw material liquid 300 is promoted.

  In addition, for example, when the surface tension of the raw material liquid 300 is relatively large, such as when the solute contained in the raw material liquid 300 is polyvinyl alcohol and the solvent is water, the radius of the outer peripheral circle of the first region 120a is a relatively large value. Set to.

  In this case, since the radius of the bottom surface of the Taylor cone 303 is increased, the force for the raw material liquid 300 flowing out from the opening 119 to become a sphere is weakened. As a result, the raw material liquid 300 flowing out from the opening 119 forms a stable conical shape. That is, the Taylor cone 303 is formed, and the raw material liquid 300 can be stably discharged.

  Further, when it is desired to reduce the size of the bottom surface of the Taylor cone 303 as much as possible, for example, when using the raw material liquid 300 that is easy to dry, in other words, the raw material liquid 300 that is easy to solidify, the raw material liquid 300 does not wet and spread in the Taylor cone control region 120 You may comprise only the area | region which has the predetermined wettability.

  5A to 5C are diagrams illustrating a second example of the configuration of the Taylor cone regulation region 120. FIG. Specifically, FIG. 5A is a view of the outer surface portion 116 as viewed from below, FIG. 5B is a view of the outer surface portion 116 as viewed from obliquely below, and FIG. 5C is a view of the outflow body 115 near the opening 119. It is a fragmentary sectional view.

  5A to 5C are configured by only a region having a predetermined wettability such that the raw material liquid 300 does not spread due to fluorine coating, for example. As a result, as shown in FIGS. 5B and 5C, the size of the bottom surface of the Taylor cone 303 is regulated at the edge of the opening 119.

  That is, the bottom surface of the Taylor cone 303 is held in a circular shape having a radius substantially the same as the hole diameter of the opening 119, and the raw material liquid 300 is prevented from being stagnation. Further, the surface area of the Taylor cone 303 is also reduced. Therefore, even when the raw material liquid 300 has a characteristic of being easily dried, solidification of the raw material liquid 300 and dripping from the stagnation of the raw material liquid 300 are prevented, and as a result, stable outflow of the raw material liquid 300 is achieved. It is done.

  As described above, according to the nanofiber manufacturing apparatus 100 in the embodiment, the size of the bottom surface of the Taylor cone 303 is regulated to a predetermined size or less by the Taylor cone regulation region 120 having a predetermined wettability.

  Therefore, it becomes possible to form the Taylor cone 303 having a shape corresponding to the characteristics of the raw material liquid 300, and as a result, the solidification of the raw material liquid 300 in the vicinity of the opening 119 and the dripping of the raw material liquid 300 onto the collecting means 128 are prevented. can do. In addition, the shape of the Taylor cone 303 in the plurality of openings 119 can be made uniform.

  For example, when the viscosity of the raw material liquid 300 is high, the amount of wetting and spreading of the raw material liquid 300 around the openings 119, in other words, the amount of bleeding of the raw material liquid 300 may be different in each of the plurality of openings 119. As a result, the amount of outflow per unit time of the raw material liquid 300 from each of the plurality of openings 119 is different, and the quality of the manufactured nanofiber 301 is degraded.

  However, in the nanofiber manufacturing apparatus 100 according to the embodiment, the size of the bottom surface of the Taylor cone 303 formed in each of the plurality of openings 119 can be made uniform. As a result, the outflow amount per unit time of the raw material liquid 300 from each of the plurality of openings 119 is made uniform, and high-quality nanofibers 301 can be efficiently manufactured.

  Moreover, as shown in FIGS. 4A to 4C, the nanofiber manufacturing apparatus 100 according to the embodiment can make the bottom surface of the Taylor cone 303 into a circular shape having a predetermined size. Therefore, for example, even if the shape of the opening 119 is non-circular, the conical Taylor cone 303 can be formed, and as a result, the raw material liquid 300 can be stably discharged.

  6A is a view of the outer surface portion 116 in which the rectangular opening 119a is disposed as viewed from below, and FIG. 6B is a view of the outer surface portion 116 in which the rectangular opening 119a is disposed in an obliquely downward direction. .

  As shown in FIGS. 6A and 6B, a first region 120a having a circular outer periphery is disposed so as to surround the rectangular opening 119a. A second region 120b is arranged so as to surround the first region 120a.

  Each of the first region 120a and the second region 120b has the same wettability as the first region 120a and the second region 120b shown in FIGS. 4A to 4C. That is, the raw material liquid 300 flowing out from the opening 119a spreads in the first region 120a, and the wet spread stops at the boundary between the first region 120a and the second region 120b.

  Thereby, as shown in FIG. 6B, conical Taylor cone 303 is formed in each opening 119a, and the raw material liquid 300 flows out stably from each opening 119a. Of course, the same applies to the case where the opening 119a is non-circular such as an ellipse or a triangle.

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

  First, the raw material liquid 300 is supplied to the effluent 115 by the supply means 107 (supply process). As described above, the raw material liquid 300 is filled in the storage tank 113 of the effluent 115.

  Next, the charging electrode 121 is set to a positive or negative high voltage by the charging power source 122. Charge concentrates on the outer surface portion 116 of the outflow body 115 facing the charging electrode 121, and the charge passes through the outflow hole 118 and is transferred to the raw material liquid 300 flowing into the space, so that the raw material liquid 300 is charged (charging process). ).

  The charging step and the supplying step are performed at the same time, and the charged raw material liquid 300 flows out from the opening 119 of the outflow body 115 (outflow step).

  Here, the raw material liquid 300 flowing out from the opening 119 forms the Taylor cone 303 as described above. When forming the Taylor cone 303, the size of the bottom surface of the Taylor cone 303 is regulated by the Taylor cone regulation region 120 (Taylor cone regulation process).

  Next, the nanofiber 301 is manufactured by an electrostatic stretching phenomenon acting on the raw material liquid 300 that has flew in the space to some extent (a nanofiber manufacturing process). Here, the raw material liquid 300 flows out in a strong charged state (high charge density) without being influenced by the ion wind, and the raw material liquid 300 flying from each opening 119 flows out in a thin state without being collected. Thereby, most of the raw material liquid 300 is changed to the nanofiber 301. In addition, since the raw material liquid 300 flows out in a strongly charged state (high charge density), electrostatic stretching occurs over many orders, and a large amount of nanofibers 301 with a small wire diameter are manufactured.

  In this state, the nanofiber 301 is attracted to the collecting means 128 by the electric field generated between the attracting means 104 and the outflow body 115 arranged behind the collecting means 128 (attraction process).

  Thus, the nanofiber 301 is deposited and collected on the collecting means 128 (collecting step). Since the collecting means 128 is slowly transferred by the moving means 129, the nanofiber 301 is also collected as a long belt-like member extending in the transfer direction.

  By using the nanofiber manufacturing apparatus 100 configured as described above and carrying out the above nanofiber manufacturing method, the size of the bottom surface of the Taylor cone 303 formed by the raw material liquid 300 flowing out from the effluent 115 is determined as the raw material. The size can be regulated according to the characteristics of the liquid 300. As a result, it is possible to uniformly manufacture high-quality nanofibers 301 while maintaining high production efficiency.

  The present invention is not limited to the above embodiment. For example, the Taylor cone 303 may be generated even if the outer surface portion 116 is not flat. Therefore, the outer surface portion 116 is not limited to one having a rectangular plane.

FIG. 7 is a view of the outer surface portion 116 having a curved surface as viewed obliquely from below.
As shown in FIG. 7, even when the outer surface portion 116 has a curved surface, the size of the bottom surface of the Taylor cone 303 in each opening 119 is obtained by arranging the Taylor cone regulation region 120 on the outer surface portion 116. Control is possible.

  Further, even if the outer surface portion 116 has a shape other than a single plane and a phase surface, if the Taylor cone 303 is formed, the Taylor cone regulation region 120 is disposed on the outer surface portion 116, so that the embodiment can be realized. Similarly, the size of the bottom surface of the Taylor cone 303 can be controlled.

  In addition, you may arrange | position the Taylor cone control area | region 120 comprised only in the area | region which has the predetermined wettability of the grade which the raw material liquid 300 demonstrated in FIG.

  In this embodiment, the outflow body 115 is provided with a plurality of outflow holes 118 and a plurality of openings 119. However, the outflow body 115 may be provided with only one set of outflow holes 118 and openings 119.

  In the present embodiment, the charging electrode 121 also functions as the attracting means 104 for attracting the nanofiber 301. However, the present invention is not limited to this configuration, and the attracting means 104 and the charging electrode 121 may be provided as separate components. For example, the attracting means 114 does not attract the nanofiber 301 by an electric field, and may attract the nanofiber 301 by air suction or air blowing.

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

DESCRIPTION OF SYMBOLS 100 Nanofiber manufacturing apparatus 104 Attraction means 107 Supply means 113 Storage tank 114 Guide pipe 115 Outflow body 116 Outer surface part 117 Side surface part 118 Outflow hole 119,119a Opening part 120 Taylor cone control area | region 120a 1st area | region 120b 2nd area | region 121 Charging electrode 122 Charging power supply 127 Roll 128 Collecting means 129 Moving means 151 Container 300 Raw material liquid 301 Nanofiber 303 Taylor cone

Claims (4)

A nanofiber manufacturing apparatus for manufacturing nanofibers by electrically stretching a raw material liquid in a space,
An outflow body having an outflow hole for allowing the raw material liquid to flow out into the space, and an outflow body having an outer surface portion in which an opening which is a tip of the outflow hole is disposed;
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 outer surface portion has a wettability to suppress wetting and spreading of the raw material liquid by repelling the raw material liquid, thereby regulating the size of the bottom surface of the Taylor cone formed by the raw material liquid flowing out from the outflow hole. have a Taylor cone regulatory regions that,
The Taylor cone regulation region is formed so as to surround the opening, and has a wettability in which wetting and spreading of the raw material liquid is allowed rather than a wettability that suppresses the wetting and spreading of the raw material liquid, and A second region having a wettability that is formed so as to surround the first region and suppresses the wetting and spreading of the raw material liquid.
Nanofiber manufacturing equipment. The Taylor cone regulatory region, said by first region is less than a predetermined size, the size of the bottom surface of the Taylor cone, the nano-fiber manufacturing apparatus according to claim 1, wherein the regulating below said predetermined magnitude The outflow hole causes the raw material liquid to flow out from the non-circular opening,
Wherein the first region, the nano-fiber manufacturing apparatus according to claim 1, wherein the non-circular of the a circular region formed to surround the opening. A nanofiber manufacturing method for manufacturing a nanofiber by electrically stretching a raw material liquid in a space,
An outflow step for causing the raw material liquid to flow out into the space, and an outflow step for causing the raw material liquid to flow out from the outflow body having an outer surface portion in which an opening which is a tip of the outflow hole is disposed;
A charging step of applying a predetermined voltage between the outflow body and a charging electrode disposed at a predetermined distance from the outflow body; and
The Taylor corn regulation region of the outer surface portion has a wettability that suppresses the wetting and spreading of the raw material liquid by repelling the raw material liquid , so that the Taylor corn formed by the raw material liquid that flows out in the outflow process Including a Taylor cone regulation process that regulates the size of the bottom surface ,
The Taylor cone regulation region is formed so as to surround the opening, and has a wettability in which wetting and spreading of the raw material liquid is allowed rather than a wettability that suppresses the wetting and spreading of the raw material liquid, and A second region having a wettability formed so as to surround the first region and suppressing wetting spread of the raw material liquid,
In the Taylor cone regulation step, the nanofiber manufacturing that regulates the size of the bottom surface of the Taylor cone is suppressed in the second region, the wetting and spreading of the raw material liquid allowed to spread in the first region Method.

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