JP2016023399A - Ejection nozzle head for forming nanofibers and manufacturing apparatus of nanofibers provided with ejection nozzle head for forming nanofibers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ejection nozzle head for forming nanofibers capable of avoiding formation of short fibers or particles, ensuring a manufacturing quantity, and reducing diameter with a compact apparatus, and to provide a manufacturing apparatus of nanofibers provided with an ejection nozzle head for forming nanofibers.SOLUTION: An ejection nozzle head 12 for forming nanofibers has: a plurality of polymer material ejection ports 42 for ejecting a polymer material in a molten state with a viscosity lower than a prescribed viscosity; and a single air ejection port 44 for ejecting air heated to a temperature at least higher than a temperature of the polymer material in the molten state at a speed at least higher than a speed of ejection of the polymer material in the molten state in a direction same as the direction of ejecting the polymer material in the molten state. The plurality of polymer material ejection ports 42 are arranged around the single air ejection port 44 on the downstream side in the direction of ejection from the single air ejection port 44 so that a polymer material C in the molten state ejected from each of the plurality of polymer material ejection ports 42 is rolled in a flow of the air ejected from the single air ejection port 44 and is drawn in the direction of ejection.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a nanofiber forming spray nozzle head and a nanofiber manufacturing apparatus including the nanofiber forming spray nozzle head. The present invention relates to an injection nozzle head for forming nanofibers that can be reduced in diameter while ensuring a production amount, and a nanofiber manufacturing apparatus including the injection nozzle head for forming nanofibers.

To date, nanofibers are broadly classified into unique effects such as a super specific surface area effect, a nanosize effect, and a supramolecular arrangement effect, and exhibit the following unique characteristics from these effects.
Specifically, from the super specific surface area effect, from the molecular recognition and adsorption characteristics, from the nanosize effect, from the hydrodynamic characteristics and optical characteristics, from the supramolecular arrangement effect, from the electrical characteristics, mechanical characteristics and thermal characteristics, Recognized as unique characteristics not seen in the past, and based on these new characteristics, for example, electrical and electronic fields, filter fields, medical fields, clothing fields, biotechnology fields, automotive fields, building materials fields, energy fields The way to various uses is being sought.

Conventionally, as a method of producing nanofibers using a polymer material as a raw material, for example, Patent Document 1 discloses an electrospinning method (charge-induced spinning method).
The electrospinning polymer web manufacturing apparatus includes a barrel that stores at least one polymer material in a liquid state, a pump that pressurizes and supplies liquid polymer material stored in the barrel, and a pump that supplies the polymer material. A spinning unit that injects the liquid polymer material through at least one charged nozzle, and a charge that charges the polymer material discharged through the nozzle of the spinning unit to any one polarity. A voltage generation unit, and a collector that forms a polymer web by transporting while laminating the spinning charged to a polarity different from the charged polarity of the spinning unit and discharged from the nozzle.

According to such a polymer web manufacturing apparatus, a polymer solution diluted and stored in a barrel with a solvent is supplied by a pump toward a nozzle to which a high voltage is applied by a first high voltage generator. Charge is charged to the polymer solution that flows out linearly from the nozzle, and the distance between the charged charges decreases as the solvent of the polymer solution evaporates, so that the acting Coulomb force increases and the Coulomb force becomes linear. When the surface tension of the polymer solution exceeds the linear tension, a linear polymer solution is stretched explosively, and this phenomenon called electrostatic explosion is repeated as primary, secondary, and in some cases tertiary. As a result, a nanofiber made of a polymer having a submicron diameter is manufactured.

  In this method, 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 with a nozzle or the like, and a charge is applied to the polymer solution to charge the space. In this method, nanofibers are obtained by electrically stretching a polymer solution.

  More specifically, the polymer solution charged and discharged into the space gradually evaporates the solvent while flying through the space. As a result, the volume of the polymer solution in flight gradually decreases, but the charge imparted to the polymer solution remains in the polymer solution. As a result, the charge density of the polymer solution flying in space gradually increases. Since the solvent continues to evaporate, the charge density of the polymer solution further increases, and the repulsive Coulomb force generated in the polymer solution is higher than the surface tension of the polymer solution. A phenomenon occurs in which the molecular solution is stretched linearly explosively. Such electrostatic stretching phenomenon occurs geometrically in succession in the space, and thereby nanofibers made of a polymer having a diameter of the order of submicron are manufactured.

  By depositing the nanofibers thus manufactured on an electrically grounded collector, a three-dimensional thin film having a three-dimensional network can be obtained, and by forming it thicker, it has a submicron network. A highly porous web can be produced. The highly porous webs thus produced can be suitably applied to filters, battery separators, polymer electrolyte membranes and electrodes of fuel cells, etc., and by applying this highly porous web made of nanofibers, respectively. It can be expected to dramatically improve the performance.

However, the conventional electrospinning method uses a repulsive force and a suction force due to electrostatic force (Coulomb force) after the polymer material is once dissolved in a solvent to stretch the polymer material. Therefore, first, the mechanism of stretching, second, the quality of the nanofibers, third, the compatibility between ensuring the quality of the nanofibers and increasing the production amount, and fourth, the types of applicable polymer materials Have technical problems.
Regarding the first point, in order to use electrostatic explosion, it is necessary to increase the charge density in the polymer material. For that purpose, once the raw material liquid is diluted with a solvent, Uses a mechanism that evaporates the solvent by jetting and stretches as the charge repulsive force increases due to an increase in charge density, thereby rapidly increasing the surface area and accelerating the evaporation of the solvent. Therefore, if the initial dilution of the raw material liquid is insufficient, the charge density does not increase during the injection of the polymer material, and no stretching is caused no matter how high voltage is applied. As described above, once the stretching required for nanofiber formation is initiated, it is geometrically promoted. However, the trigger for starting stretching is lacking in flexibility. In manufacturing the fiber, the initial dilution of the raw material liquid, that is, how much the concentration of the raw material liquid is set must be determined by trial and error.
Regarding the second point, since the polymer material is stretched while spinning under the influence of electric field interference, the diameter of the nanofiber is likely to vary, and the substrate is caused by electric field interference and ionic wind. The layer thickness of the nanofiber laminated on the surface is likely to vary.

Regarding the third point, since the polymer material is dissolved in the solvent and the solvent is evaporated, the applied voltage and the polymer are increased in order to increase the production amount of nanofibers in addition to the poor yield. When the pressure of the material is increased, the needle-shaped nozzle is electrically neutralized by electrostatic induction, and it becomes difficult to give a charge to the polymer material.
More specifically, a charged nanofiber cloud is formed between the needle-shaped nozzle and the substrate when a polymer material charged with the same polarity by the needle-shaped nozzle is ejected. This charged nanofiber Due to the clouds, charges of the same polarity are electrostatically induced in the needle-like nozzle and are neutralized electrically, making it difficult to continuously charge the polymer material. As a result, the polymer material is in the form of droplets or beads and degrades the quality.
For example, in the case of a nanofiber filter, such droplets or beads cause clogging and greatly reduce the filter performance.
In addition, in order to increase the production amount of nanofibers, it is necessary to secure an interval between adjacent nozzles in order to avoid electric field interference when using a large number of needle-shaped nozzles at one time. Complicating and increasing the size of the nanofiber manufacturing device itself are essential.

  As for the fourth point, since a high voltage of several tens of thousands of volts is used, there is a risk of explosion in the case of a flammable solvent. For this reason, it is necessary to use water or a non-flammable solvent as the solvent. If only a polymer material suitable for such a solvent is applied, the types of polymer material that can be applied are limited.

In this regard, Non-Patent Document 2 discloses a microfiber manufacturing method and manufacturing apparatus using a melt-type blow method.
This microfiber manufacturing apparatus has a blowing nozzle, and the blowing nozzle has an inner thermoplastic resin blowing nozzle and an outer air blowing nozzle arranged concentrically in a nested manner, and the blowing nozzle for thermoplastic resin. Has a linear flow path for the thermoplastic resin extending to the thermoplastic resin blowing outlet, and the air blowing nozzle cooperates with the outer peripheral surface of the inner thermoplastic resin blowing nozzle to blow the tip air blowing. An air flow passage extending to the outlet is formed, and an air outlet is disposed on the downstream side in the outlet direction of the thermoplastic resin outlet, concentrically with the thermoplastic outlet, and in the vicinity of the thermoplastic outlet. The outer peripheral surface of the thermoplastic resin blowing nozzle is tapered toward the thermoplastic resin blowing nozzle, and correspondingly, in the vicinity of the air blowing port The outer peripheral surface of the air blowing nozzle is also tapered, so that the air flowing through the air annular channel around the air blowing port is for the thermoplastic resin as opposed to the thermoplastic resin blowing out from the thermoplastic resin blowing port. The air annular flow path portion is formed in a tapered shape so as to collide with the downstream side from the air outlet and the upstream side from the air outlet.

This method is a melt spinning method in which a nonwoven fabric is formed from a thermoplastic resin in one step. A thermoplastic resin melted by an extruder is heated at a high temperature and high pressure from a nozzle having several hundred to 1000 or more nozzles per meter in the width direction. A thermoplastic resin that is blown out into a string using air flow and stretched into a fiber is accumulated on a conveyor, and the fibers are entangled and fused between them, thereby making it possible to produce self-adhesive ultrafine fibers that do not require a binder. A web is formed.
According to such a melt-type blow method, it is possible to suppress a decrease in yield in that the thermoplastic resin is heated and melted without being dissolved in a solvent, and on the other hand, electrostatic force is used for stretching the polymer material. However, the above technical problem caused by electric field interference, ion wind or electrostatic induction can be solved in that the flow of the thermoplastic resin is drawn into the air flow.

However, there are the following technical problems in the microfiber manufacturing method and manufacturing apparatus by such a melt-blowing method.
First, the diameter reduction of the thermoplastic resin is at the micro level, and it is difficult to produce nanofibers.
More specifically, the flow of high-speed air ejected from a single air blowing nozzle is collided with the flow of thermoplastic resin ejected from a single thermoplastic resin blowing port, and the diameter is further reduced. Therefore, if the speed of air is increased, shortening or particle formation is caused during stretching. Furthermore, when the air speed is increased, the molten thermoplastic resin is cooled, and stretching is limited.
Second, it is difficult to efficiently produce a large amount of fiber at once.
More specifically, since a single air blowing nozzle is individually arranged around a single thermoplastic resin outlet, if a large number of fibers are manufactured at one time, It is necessary to prepare a plurality of such dies, and in particular, the amount of air consumption associated with the production increases dramatically.
Thirdly, the manufactured fiber is limited to the nonwoven fabric, and it is difficult to manufacture various types of fibers.

In this regard, if the solvent-type blow type is adopted instead of the melt-type blow type, the polymer material is dissolved in the solvent, thereby reducing the viscosity of the polymer material so that it can be stretched. Since the solvent is contained, the yield of nanofiber is poor. Therefore, if the low yield is compensated by increasing the injection flow rate of the polymer material, the higher the injection speed of the polymer material, the more the evaporation of the solvent is promoted and the viscosity of the polymer material increases. If the jetting speed of is constant, the degree of stretching due to the entrainment of the polymer material in the air flow decreases. If the air injection speed is increased in order to compensate for the decrease in stretching, when the polymer material is entrained, similarly, shortening or particle formation is caused, and generation of fiberized nanofibers is caused. It becomes difficult.
As described above, according to the solvent-type blow type, it is technically difficult to produce nanofibers that have been made into desired small-diameter fibers while ensuring the production amount of nanofibers.

  Patent Document 3 discloses a nanofiber manufacturing apparatus and manufacturing method in which an air blowing method and an electrospinning method are combined in a melt type.

More specifically, by supplying a polymer material in a molten state to a needle-like nozzle to which a high voltage is applied, a charge is charged in the polymer material that flows out linearly from the needle-like nozzle, In addition to receiving a repulsive force, high-temperature and high-speed air is blown in a direction substantially perpendicular to the injection direction from the nozzle, and the flow of the polymer material is entrained in the high-temperature and high-speed air. The polymer material is stretched by being entrained in the air.

  According to such a hybrid system of the so-called air blow method and electrospinning method, to achieve the stretching necessary for making the polymer material into nanofibers, the burden on each method is reduced, that is, By reducing the air injection speed by the air blowing method or the voltage level by the electrospinning method, the technical problems in the case of the air blowing method and the electrospinning method alone are alleviated somewhat. Although it may be possible, the use of a melt-type hybrid system causes new technical problems.

First, the air injection speed and voltage to achieve the desired nanofiber diameter due to stretching the polymer material by repulsion due to charge and entrainment in high temperature and high speed air. It takes considerable trial and error to adjust the height of the fiber, making it difficult to produce stable nanofibers.

  More specifically, in particular, since the injection direction of the polymer material due to the repulsive force from the nozzle and the air blowing direction are substantially orthogonal, the higher the voltage, the higher the repulsive force from the nozzle. Is likely to enter a high-speed flow at the center of a high-temperature and high-speed air flow, and a rapid entrainment due to the high-speed flow at the center tends to cause shortening or particle formation of the polymer material. On the other hand, as the air injection speed is increased, the air itself is cooled before the polymer material is entrained, and it becomes difficult to cool the polymer material and maintain the molten state during entrainment.

Second, if the hybrid method is performed by the melt method instead of the solvent method, for the air blow method, the polymer material is melted in advance, thereby contributing to stretching by setting the viscosity to a predetermined value or less. However, for the electrospinning method, once the polymer material is diluted in the solvent method, the solvent is evaporated during the injection, and the charge density is rapidly increased to achieve explosive stretching. Unlikely, it is not predictable how much stretching is possible.

JP 2002-201559 Tapils website Melt-Blown manufacturing method JP 2014-111850

In view of the above technical problems, the object of the present invention is to form a nanofiber that can be reduced in diameter while ensuring a production amount without causing shortening or particle formation while being a simple and compact device. Provided is a nanofiber manufacturing apparatus comprising an injection nozzle head for use and an injection nozzle head for forming nanofibers.
In view of the above technical problems, the object of the present invention is to provide a nanofiber that can be used for general-purpose production of nanofibers having a desired fiber diameter and / or entanglement degree regardless of the type of the polymer material without variation in quality. A manufacturing apparatus is provided.

In order to achieve the above object, the nanofiber-forming jet nozzle head of the present invention is:
A plurality of polymer material injection ports for injecting a molten polymer material having a predetermined viscosity or less, and at least air heated to a temperature higher than the temperature of the polymer material in the molten state, based on at least the injection speed of the polymer material in the molten state A single air injection port that injects in the same direction as the injection direction of the molten polymer material at high speed,
The plurality of macromolecules so that the polymer material in a molten state ejected from each of the plurality of polymer material ejection ports is caught in a flow of air ejected from the single air ejection port and extends in the ejection direction. The material injection port is configured to be provided on the downstream side in the injection direction from the single air injection port around the single air injection port.

According to the nanofiber-forming jet nozzle head having the above configuration, at least a molten polymer material is melted from the air jet port while jetting a molten polymer material having a predetermined viscosity or less from the polymer material jet port. When air heated to a temperature higher than the temperature is at least faster than the injection speed of the polymer material in the molten state and in the same direction as the injection direction of the polymer material in the molten state, the melt injected from the polymer material injection port The plurality of polymer material injection ports are arranged around the single air injection port so that the polymer material in the state is caught in the air flow from the single air injection port and extends in the injection direction. Since it is provided downstream from the air injection port in the injection direction, when the flow of the molten polymer material having a predetermined viscosity or less is caught in the air flow, the polymer material is cooled to the melting point or less by the air. Without being stretched in the injection direction by the flow of air and thereby reduced in diameter, depending on the type of polymer material, for example, the flow rate of the molten polymer material is reduced while the air injection speed is increased. It is possible to form nanofibers by adjusting the above.

      The plurality of polymer material injection ports are arranged concentrically around the single air injection port, and the polymer material injection ports adjacent in the circumferential direction are spaced apart from each other by a predetermined angle. Is good.

Furthermore, the nanofiber-forming jet nozzle head is a monolithic solid body having opposing end surfaces and a peripheral side surface between the opposing end surfaces,
The plurality of polymer material injection ports and the widest diameter opening of the divergent nozzle are formed on one end surface of the opposed end surfaces,
In the monolithic solid body, one end opening forms the polymer material injection opening, and a polymer material through-hole forming a flow path of the polymer material is provided, and one end opening is the single opening. An air through hole is formed, forming an air injection opening and constituting an air flow path,
The divergent nozzle is configured as a through passage that communicates with the other end opening of the air through hole and extends toward one end face of the opposing end face,
Further, the other end opening of the through hole for polymer material is provided on the other end surface of the opposed end surface, and the through hole for polymer material extends in the longitudinal direction of the monolithic solid body,
The other end opening of the air through hole may be provided on the peripheral side surface, and the polymer material through hole may have a portion extending in a direction crossing the longitudinal direction of the monolithic solid body.

Furthermore, a concave polymer material reservoir is formed on the other end surface of the opposing end surfaces,
Each of the polymer material through holes may communicate with the polymer material reservoir.

In order to achieve the above object, the nanofiber production apparatus of the present invention comprises:
An injection nozzle head for forming nanofibers according to any one of claims 1 to 4,
A polymer material supply unit for supplying a polymer material toward the nanofiber-forming jet nozzle head;
An air supply unit that supplies air toward the nanofiber-forming injection nozzle head;
The polymer material supply unit includes a polymer material heating unit and a polymer material kneading and conveying unit.
The air supply unit includes an air heating unit and an air pressure feeding unit.

Further, the polymer material supply unit has a cylindrical body constituting a kneading and conveying space for the polymeric material therein, and the cylindrical body is provided with an inlet for receiving a bead-shaped polymeric material raw material, In the kneading and conveying space, a spiral screw for kneading and conveying the bead-shaped polymer material raw material is disposed,
A band heater is wound around the outer peripheral surface of the nanofiber-forming spray nozzle head and the outer peripheral surface of the portion corresponding to the kneading and conveying space of the cylindrical body,
The nanofiber-forming injection nozzle head has the other end face abutted against the end face of the cylindrical body so that the axial direction thereof coincides with the axial direction of the helical screw. It is good to be provided.

Further, a cleaning liquid supply unit for cleaning the plurality of polymer material through holes is provided, and the cleaning liquid supply unit is provided from the other end opening of each of the plurality of polymer material through holes to one end opening. The cleaning liquid may be supplied to the inside.
Furthermore, it has an external air conveyance pipe connected so as to be able to communicate with the other end opening of the air through hole,
The air heating means is a band-type air heater wound around the outer peripheral surface of the air pressure feeding means and the external air conveyance pipe,
The air pressure feeding means may be an air air compressor connected to an end of the external air conveyance pipe.

Further, a polymer material temperature detecting means for detecting the temperature of the polymer material in the kneading and conveying space, and a flow rate of the polymer material kneaded and conveyed from the kneading and conveying space toward the plurality of polymer material through holes. A polymeric material flow rate detecting means for detecting air temperature detecting means for detecting the temperature of air in the air flow path, and an air flow rate detecting means for detecting the flow rate of air in the air flow path,
Based on the temperature of the polymer material detected by the polymer material temperature detection means and the flow rate of the polymer material detected by the polymer material flow rate detection means, the heating amount of the band heater and / or the spiral And controlling the number of rotations of the screw and the heating amount of the band-type air heater and / or the temperature of the air detected by the air temperature detecting means and the air flow detected by the air flow detecting means. Or it is good to have a control part which controls the discharge pressure of the air air compressor.

The nanofiber manufacturing apparatus may be a portable type with a caster.
Further, each of the through holes for the polymer material includes an enlarged diameter portion communicating with the polymer material reservoir, a reduced diameter portion communicating with the polymer material injection port, the enlarged diameter portion, and the reduced diameter portion. It is preferable to have a tapered portion that connects the two.
In addition, the polymer material may include a thermoplastic resin, a thermoplastic elastomer, polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, and a polypeptide.

A nanofiber manufacturing apparatus according to a first embodiment of the present invention will be described below in detail with reference to the drawings.

  Here, the raw materials of the nanofiber include polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, polyvinylidene fluoride, polyfluoride. Heat of vinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, polyamide, aramid, polyimide, etc. A plastic resin can be illustrated, 1 type chosen from these may be sufficient, and multiple types may be mixed.

As shown in FIG. 1, the nanofiber manufacturing apparatus 10 includes a nanofiber-forming injection nozzle head 12, a thermoplastic resin supply unit 14 that supplies a thermoplastic resin toward the nanofiber-forming injection nozzle head 12, An air supply unit 16 that supplies air toward the fiber forming jet nozzle head 12. The thermoplastic resin supply unit 14 includes a thermoplastic resin heating unit 18 and a thermoplastic resin kneading and conveying unit 20. The air supply unit 16 includes an air heating unit 22 and an air pressure feeding unit 24.

As shown in FIG. 2, the thermoplastic resin supply unit 14 has a cylindrical barrel constituting a kneading and conveying space 26 for the thermoplastic resin therein, and the barrel is made of a thermoplastic resin material in the form of beads or pellets. The kneading and conveying space 26 is provided with a helical screw 30 for kneading and conveying the thermoplastic resin material, and a band-like shape is provided on the outer peripheral surface of the portion corresponding to the kneading and conveying space 26 of the cylindrical body. The heaters 32A, B, and C are wound in a state of being spaced apart from each other in the axial direction of the barrel, and the nanofiber-forming injection nozzle head 12 has an axial direction that coincides with the axial direction of the spiral screw 30. The other end face 54B is abutted with the end face of the cylindrical body, so that it is provided in front of the spiral screw 30.
The nanofiber-forming injection nozzle head 12 is connected and fixed to the barrel side through a plurality of screw holes 57 in a screwed form.
The tip of the spiral screw 30 is provided so as to face the thermoplastic resin reservoir 62 of the nanofiber forming injection nozzle head 12 described later.

The spiral screw 30 is connected to a screw drive motor 31 at its proximal end, supported by a barrel via a rotary bearing (not shown), and is driven to rotate about the axial direction of the barrel by the screw drive motor 31.

  A funnel-shaped hopper 28 for supplying the thermoplastic resin to the barrel is attached to the base end side of the barrel, and the thermoplastic resin is supplied into the kneading and conveying space 26 of the barrel through the hopper 28 in the form of pellets or beads. .

The barrel is divided into a plurality of temperature control zones, for example, Z1 to Z5 along the axial direction. Corresponding to each temperature control zone Z2 to Z4, band heaters 32A, B, C are provided so as to surround the barrel. Corresponding to the temperature control zone Z5, a band heater 32D is installed on the peripheral side surface 56 of the nanofiber forming jet nozzle head 12 in the same manner as the barrel. On the other hand, a cooling device 35 is provided on the hopper 28 side of the barrel corresponding to the temperature control zone Z1.
Regarding the band heaters 32A, B, C, and D, the outer surface temperature of the barrel is set to be a band heater so that the thermoplastic resin gradually melts as the temperature of the thermoplastic resin approaches each of the thermoplastic resin injection ports 42. The heating temperature of 32A <the heating temperature of the band heaters 32B and C <the heating temperature of the band heater 32D, so that the temperature of the thermoplastic resin in the barrel corresponding to each temperature control zone Z2 to Z4 is set. adjust.

As shown in FIGS. 3 to 5, the nanofiber forming injection nozzle head 12 includes a plurality of thermoplastic resin injection ports 42 for injecting a molten thermoplastic resin having a predetermined viscosity or less, and at least a molten thermoplastic resin. And a single air injection port 44 that injects air heated to a temperature higher than the temperature of at least the same direction as the injection direction of the molten thermoplastic resin at a speed higher than the injection speed of the molten thermoplastic resin.

Each of the plurality of thermoplastic resin injection ports 42 has a circular shape with the same diameter, and for example, the diameter is 0.4 mm. On the other hand, the single air injection port 44 has a circular shape, for example, a diameter of 2 mm.
The plurality of thermoplastic resins so that the thermoplastic resin in a molten state injected from each of the plurality of thermoplastic resin injection ports 42 is caught in the flow of air injected from the single air injection port 44 and extends in the injection direction. The injection port 42 is provided around the single air injection port 44 and downstream of the single air injection port 44 in the injection direction.

An air compressor 16 that forms compressed air having a desired pressure is provided at the distal end of the external air conveyance pipe 61 so as to supply the compressed air via the external air conveyance pipe 61 and the internal air conveyance pipe 60.
The external air conveyance pipe 61 is connected to the nanofiber-forming injection nozzle head 12 so as to be able to communicate with the internal air conveyance pipe 60 in a threaded form. A band-type air heater 22 is wound around the outer peripheral surface of the external air conveyance pipe 61, and when the air pressure-fed from the air compressor 16 flows through the external air conveyance pipe 61, the band-type air heater 22 causes at least thermoplasticity of the air. The temperature is higher than the melting temperature of the resin.

The single air injection port 44 constitutes a diameter-reduced diameter opening 46 and has a divergent nozzle 48 that spreads from the single air injection port 44 in the air injection direction.
The divergent nozzle 48 has a truncated cone shape with an axially symmetrical structure in which a symmetric axis is arranged along the air injection direction, and the single air injection port 44 is a circular opening so that the symmetric axis passes through the center thereof. Be placed.
The divergent angle α of the divergent nozzle 48 is such that the air flow that is ejected from the single air injection port 44 has a lower speed than the high-speed central flow A around the high-speed central flow A until the air flow reaches the plurality of thermoplastic resin injection ports 42. It is set so that there is sufficient space for the flow B to be formed. In other words, if the divergent angle α is small, the range of the low-speed air flow B reaches and contacts the inner peripheral surface of the divergent nozzle 48. Therefore, the divergent angle α is set so as not to cause such a situation.
The nozzle peripheral end 52 around the maximum diameter opening 50 of the divergent nozzle 48 is cylindrical.

Next, the plurality of thermoplastic resin injection ports 42 are disposed concentrically around the single air injection port 44 around the single-diameter injection port 44 on the outer side of the largest-diameter opening 50 of the divergent nozzle 48 and are adjacent to each other in the circumferential direction. The thermoplastic resin injection ports 42 are spaced at a predetermined angular interval. Specifically, five thermoplastic resin injection holes 42A to 42E are arranged at equiangular intervals. In addition, the angular interval between the thermoplastic resin injection ports 42 adjacent in the circumferential direction is not in contact with each other until the thermoplastic resin injected from each injection port is caught in the air flow, as will be described later. And after extending | stretching, while flying in the air to the collection part 50, it progresses intertwining each other, What is necessary is just to set in consideration of the grade of such an intertwining.

The nanofiber-forming jet nozzle head 12 is a monolithic solid body having opposed end faces 54A, B and a peripheral side face 56 between the opposed end faces 54A, 54B. The monolithic solid body is cylindrical, and the material is made of SUS. The plurality of thermoplastic resin injection ports 42 and the widest diameter opening 50 of the divergent nozzle 48 are formed on one end surface 54A of the opposing end surfaces 54A, B, and one end opening is thermoplastic in the monolithic solid body. The resin injection port 42 is formed, and a thermoplastic resin through-hole 58 constituting a flow path of the thermoplastic resin is provided, and one end opening forms a single air injection port 44 to form an air flow path. The air through hole 60 is provided, and the divergent nozzle 48 is configured as a through passage that communicates with the other end opening of the air through hole 60 and extends toward one end face 54A of the opposing end faces 54A, B. .
Each of the through holes 58 for thermoplastic resin includes a diameter-expanded portion 61 that communicates with the thermoplastic resin reservoir 62, a diameter-reduced portion 59 that communicates with the thermoplastic resin injection ports 42A to 42E, a diameter-expanded portion 61, and a diameter-reduced portion. And a taper portion 55 that connects to 59. Thus, the diameter-expanded portion 61 and the thermoplastic resin reservoir portion 62 are used as a buffer space for the thermoplastic resin to ensure smooth injection of the thermoplastic resin from the thermoplastic resin injection port 42. The diameter ratio between the enlarged diameter portion 61 and the reduced diameter portion 59 may be determined from such a viewpoint.

The other end opening of the through hole 58 for thermoplastic resin is provided on the other end face 54B of the opposing end surfaces 54A and 54B. The through hole 58 for thermoplastic resin extends in the longitudinal direction of the monolithic solid body and is used for air. The other end opening of the through hole 60 is provided on the peripheral side surface 56, and the air through hole 60 has a portion extending in a direction intersecting the longitudinal direction of the monolithic solid body. Specifically, the air through hole 60 is substantially L-shaped, and the thermoplastic resin is used to avoid interference because the air through hole 60 is provided below the nanofiber-forming injection nozzle head 12. The injection ports 42A to 42E are provided in the upper part of the nanofiber forming injection nozzle head 12.
The interval D1 in the injection direction between the plurality of thermoplastic resin injection ports 42 and the single air injection port 44 and the interval D2 on one end face 54A of the plurality of thermoplastic resin injection ports 42 and the single air injection port 44 are as follows: Depending on the injection flow rate of air and the injection flow rate of the thermoplastic resin, the stretching required for the thermoplastic resin can be achieved.

On the other end face 54B of the facing end faces 54A, 54B, a hollow thermoplastic resin reservoir 62 is formed, and the nanofiber forming injection nozzle head 12 is fixed to the end face of the barrel in a threaded manner. As shown in FIG. 2, the tip of the spiral screw 30 extends to the thermoplastic resin reservoir 62, communicating with the kneading and conveying space 26 inside. Each of the through holes 58 for thermoplastic resin communicates with the thermoplastic resin reservoir 62. The thermoplastic resin reservoir 62 has a tapered shape in the upstream direction of injection, and may be, for example, a truncated cone having an axially symmetric structure. In this case, the diameter of the bottom surface of the truncated cone may be determined from the viewpoint that each through hole 58 for thermoplastic resin can be connected to the outer peripheral surface of the truncated cone.
The collection part 50 consists of a collection drum, for example, and it is made to collect nanofiber on the surrounding surface of a drum. When the nanofiber member or the nanofiber cotton is manufactured, the collection drum may be reciprocated in the axial direction of the drum during the manufacture of the nanofiber in order to adjust the layer thickness.

Further, as shown in FIG. 15, a thermoplastic resin temperature detecting means 80 for detecting the temperature of the thermoplastic resin in the kneading and conveying space 26, and kneading and conveying from the kneading and conveying space 26 toward a plurality of through holes for thermoplastic resin. The thermoplastic resin flow rate detection means 82 for detecting the flow rate of the thermoplastic resin to be performed, the air temperature detection means 84 for detecting the temperature of the air in the air flow path, and the air flow rate for detecting the flow rate of the air in the air flow path Detection means 86 is provided, and based on the temperature of the thermoplastic resin detected by the thermoplastic resin temperature detection means 80 and the flow rate of the thermoplastic resin detected by the thermoplastic resin flow rate detection means 82, the band heater 32A , B, C, and D and the number of revolutions of the spiral screw 30 are controlled, the air temperature detected by the air temperature detecting means 84, and the air flow rate detecting means Based on the air flow rate detected by the stage 86, a control unit 88 that controls the heating amount of the band type air heater 22 and the discharge pressure of the air compressor 16 is provided.
The control unit 88 may be a computer including a CPU, a memory, and a display, and performs centralized control of the air compressor 16, the drive motor 31, the band heaters 32A, B, C, and D, the cooling device 35, and the band heater 22, The operator is notified of the operating state of the nanofiber manufacturing apparatus 10. The operating state of the nanofiber manufacturing apparatus 10 is displayed on, for example, a display on the operation panel.
In this case, in the control unit 88, based on the temperature of the thermoplastic resin detected by the thermoplastic resin temperature detection means 80 and the flow rate of the thermoplastic resin detected by the thermoplastic resin flow rate detection means 82, the band heater 32A. , B, C, and D and the number of revolutions of the spiral screw 30 are controlled, and based on the air temperature detected by the air temperature detector 84 and the air flow detected by the air flow detector 86. When the heating amount of the band type air heater 22 and the discharge pressure of the air compressor 16 are controlled, the temperature difference between the target temperature of the air and the target temperature of the thermoplastic resin, the target flow rate of the air and the target flow rate of the thermoplastic resin If the target temperature and target flow rate of the thermoplastic resin are set in advance, the target temperature of air and the target flow rate of air are automatically set. You may make it set to. Or, depending on the type of thermoplastic resin material used, along with the melting point data of the thermoplastic resin material, the temperature difference between the target temperature of the air and the target temperature of the thermoplastic resin, and the target flow rate of the air and the target flow rate of the thermoplastic resin It is also possible to create a flow rate difference table.

  Further, a cleaning liquid supply unit 34 for cleaning the plurality of through holes 58 for thermoplastic resin is provided, and the cleaning liquid supply unit 34 has one end from the other end opening 56B of each of the plurality of through holes 58 for thermoplastic resin. A cleaning liquid is supplied to the inside toward the opening 56A. As a result, during maintenance of the nanofiber manufacturing apparatus 10, the solidified thermoplastic resin remaining and adhered inside each of the plurality of thermoplastic resin through holes 58 is removed to prevent clogging.

As a modification, the nanofiber manufacturing apparatus 10 may be a portable type with a caster, and, for example, when recycled PET is used as a raw material, the compact nanofiber manufacturing apparatus 10 is transported to the collection site of the recycled PET, Nanofibers may be produced on the spot.
As a further modification, in the nanofiber forming injection nozzle head 12, each of the plurality of thermoplastic resin injection ports 42 and the diameter of the single air injection port 44, the plurality of thermoplastic resin injection ports 42 and the single air injection port 44. A plurality of nanofiber-forming injection nozzle heads that differ in at least one of the interval D1 in the injection direction and the interval D2 on one end face 54A of the plurality of thermoplastic resin injection ports 42 and the single air injection port 44 12 may be prepared, and selected from a plurality of nanofiber forming nozzle heads 12 according to the type of thermoplastic resin. Thereby, it is possible to more reliably produce nanofibers having a desired diameter regardless of the type of thermoplastic resin.

According to the nanofiber-forming injection nozzle head 12 having the above-described configuration, at least molten heat is injected from the air injection port 44 while injecting a molten thermoplastic resin having a predetermined viscosity or less from the thermoplastic resin injection port 42. When the air heated to a temperature higher than the temperature of the thermoplastic resin is jetted in the same direction as the jet direction of the molten thermoplastic resin at least at a higher speed than the jet speed of the molten thermoplastic resin, the thermoplastic resin injection port 42. The plurality of thermoplastic resin injection ports so that the molten thermoplastic resin injected from the thermoplastic resin injection port 42 is caught in the air flow from the single air injection port 44 and extends in the injection direction. 42 is provided around the single air injection port 44 on the downstream side in the injection direction from the single air injection port 44, so that the flow of the molten thermoplastic resin having a predetermined viscosity or less When being entrained in the flow of air, it is not cooled to below the melting point by air, but is stretched in the injection direction by the air flow, thereby reducing its diameter, and depending on the type of thermoplastic resin, for example, melting Nanofibers can be formed by adjusting the flow rate of the thermoplastic resin in the state while adjusting the air injection speed.

The operation of the nanofiber manufacturing apparatus 10 having the above configuration, including the nanofiber manufacturing method, will be described in detail below with reference to FIG. 6 in particular.
The nanofiber manufacturing method uses a nanofiber manufacturing apparatus 10 to inject a thermoplastic resin that is heated and melted so as to have a predetermined viscosity or less into a thread shape, while entraining the flow of the thermoplastic resin. Injecting air heated to a temperature higher than the melting temperature of the thermoplastic resin in parallel to the same direction as the injection direction of the thermoplastic resin at a higher injection speed than the injection speed, thereby causing a high-speed center along the injection direction A flow region and a peripheral flow region that is slower than the central flow region are formed around the flow region, and the filamentous thermoplastic resin maintained in a molten state is gradually drawn from the outer periphery of the peripheral flow region toward the central flow region. As a result, the nanofibers that have been drawn and formed in the air are received and collected. More specific description will be given below.

  First, the air compressor 16 is driven, and air is supplied toward the nanofiber forming injection nozzle head 12 through the external transport pipe 61 so that the injection speed is higher than the injection speed of the thermoplastic resin. At that time, air is heated by the band heater 22 so that the temperature becomes higher than the melting temperature of the thermoplastic resin. Next, high-temperature and high-pressure air is ejected from the single air ejection port 44 in the horizontal direction through the internal conveyance pipe 60. At that time, the center flow A is generated by the high-temperature and high-pressure air, a pressure difference is generated around the center flow A, and the peripheral flow B of the low-speed and low-pressure air is generated from the center flow A.

Next, a thermoplastic resin is injected from each of the thermoplastic resin injection ports 42A to 42E. More specifically, a bead-shaped or pellet-shaped thermoplastic resin raw material is supplied from the hopper 28 into the barrel, and the thermoplastic resin raw material is heated by the band heaters 32A, B, C provided on the outer peripheral surface of the barrel. At the same time, the helical screw 30 rotated by the drive motor 61 is kneaded and conveyed toward the nanofiber forming injection nozzle head 12.
In this case, while the thermoplastic resin raw material is kneaded and conveyed by the band type heaters 32A, 32B, and 32C, it is gradually heated so as to be in a molten state, while the hopper 28 is overheated by the cooling device. Is prevented.
In each temperature control zone Z1-Z5, based on the detection result of the thermoplastic resin temperature detection means 80, the control part 88 controls the cooling device 35 and the band type heaters 32A, B, C, and D to each target temperature. .

  Taking the temperature control zone Z2 as an example, the detection result of the thermoplastic resin temperature detecting means 80 provided in the barrel is output to the control section 88, and the control section outputs the output value (barrel temperature) of the thermoplastic resin temperature detecting means 80. ) And the set target temperature, the correction value is calculated, and based on the correction value, the controller 88 controls the driving of the band heater 32A. The target temperature is set to a different value in each temperature control zone.

Next, the molten thermoplastic resin raw material temporarily accumulates in the thermoplastic resin reservoir 62 and horizontally extends from the thermoplastic resin injection holes 42A to 42E via the thermoplastic resin through holes 58A to 58E, respectively. Spray. More specifically, the molten thermoplastic resin raw material stored in the thermoplastic resin reservoir 62 is supplied to each of the through holes 58A to 58E for the thermoplastic resin almost evenly. The thermoplastic resin injection ports 42A to 42E are reached through the portion 61, the tapered portion 55, and the reduced diameter portion 59. As a result, the expanded diameter portion 61 further functions as a temporary reservoir so that the molten thermoplastic resin material can be smoothly injected without causing a stagnation from the thermoplastic resin injection ports 42A to 42E. ing.
At that time, the injection direction of the thermoplastic resin material in the molten state injected from each of the thermoplastic resin injection ports 42A to 42E is made substantially parallel to the air flow injected from the single air injection port 44.

Next, the thermoplastic resin is injected at a higher injection speed than at least the injection speed of the thermoplastic resin so as to entrain the flow of the thermoplastic resin while injecting the thermoplastic resin heated and melted so as to have a predetermined viscosity or less into a thread shape. In the same direction as the direction, air heated to at least a temperature higher than the heating temperature is jetted, and thereby the filament-like molten thermoplastic resin is stretched to be nanoscaled to the nano level.
When injecting air, along the injection direction, a high-speed central flow region A and a surrounding peripheral flow region B around the central flow region A are generated, and by injecting the thermoplastic resin, The thermoplastic resin is drawn by being gradually wound from the outer periphery of the peripheral flow region B toward the central flow region A.

More specifically, as shown in FIG. 6, the molten thermoplastic resin raw material injected into the thread form from each of the thermoplastic resin injection ports 42 </ b> A to 42 </ b> E is caught in the air flow injected from the single air injection port 44. Is stretched.
More specifically, the flow C of the thermoplastic resin is first entangled in the low-speed peripheral flow B toward the central flow A, where the thread-like thermoplastic resin is stretched and further entrapped in the central flow A. More stretched, the thread-shaped thermoplastic resin is reduced in diameter, and D3 forms a stretched region.
In this way, the flow of the thread-like thermoplastic resin maintained in the molten state is gradually stretched stepwise and proceeds to the collecting unit 50 while being entangled in the air, so that the thermoplastic resin is conventionally obtained. It is possible to effectively prevent short fibers or particles from being formed by rapidly stretching the flow.

As described above, by arranging the thermoplastic resin injection ports 42A to 42E concentrically around the single air injection port 44 and centering on the single air injection port 44, the thermoplastic resin injection ports 42A to 42E are respectively provided. The single air injection port 44 is shared, thereby reducing the amount of air required to manufacture nanofibers compared to a one-to-one correspondence between the thermoplastic resin injection port and the air injection port. It is possible to manufacture the manufactured nanofibers at low cost.
By adjusting the distance D1 in the injection direction between the single air injection port 44 and the thermoplastic resin injection port 42, the air injected from the single air injection port 44 directly hits the thermoplastic resin injection port 42 to generate heat. It is possible to prevent the plastic resin from being ejected in the form of a thread, and in some cases, it is possible to prevent the thermoplastic resin from dripping on the end face 54A.
On the other hand, by adjusting the radial distance D2 between the single air injection port 44 and the thermoplastic resin injection port 42, the degree of entrainment of the thermoplastic resin in the air flow is adjusted when the air injection flow rate is constant. Is possible.

Next, by drawing the nanofibers generated in the air by stretching the thermoplastic resin, the thermoplastic resin is collected as filamentous long fibers (filament yarns) in the collection unit 50. It has a step of collecting by receiving nanofibers generated in the air.
In the maintenance, the thermoplastic resin adhering to the insides of the through holes 58A to 58E for the thermoplastic resin may be cleaned with a cleaning liquid. Thereby, clogging of the through holes 58A to 58E for the thermoplastic resin can be effectively prevented.

How to manufacture according to the specification of the nanofiber made of thermoplastic resin will be described below.
According to the required diameter of the nanofiber made of thermoplastic resin and the type of thermoplastic resin, the heating temperature and the injection flow rate of the thermoplastic resin are determined, and based on the determined heating temperature and injection flow rate of the thermoplastic resin, Determine the heating temperature and injection flow rate.
At this time, the method has a step of adjusting the range covered by the high-speed central flow region and the low-speed peripheral flow region by adjusting the air injection flow rate.
Mainly focusing on the nanofiber production amount and nanofiber diameter per hour, and using the thermoplastic resin temperature, jet flow rate, air temperature, jet flow rate as control parameters, depending on the type of thermoplastic resin, especially the melting point In order to achieve a desired nanofiber production amount and / or nanofiber diameter per trial and error, a band heater 32 that heats the thermoplastic resin, and a drive motor 31 that rotationally drives the helical screw 30. The band heater 22 for heating the air and the air air compressor 16 for supplying the air are controlled.

More specifically, when the production amount of nanofibers per time is constant and the nanofiber diameter is further reduced, the rotational speed of the helical screw 30 is increased by the drive motor 31 and the thermoplastic resin is increased. In order to maintain the thermoplastic resin in a molten state, the heating amount per hour of the band heaters 32A, B, C, and D is increased accordingly. On the other hand, according to the increase in the injection flow rate of the thermoplastic resin, the air injection flow rate is increased by the air-air compressor 16 so as to be commensurate with it, and the viscosity is lowered further by the air injected by the thermoplastic resin to be injected. Therefore, the air is further heated by the band heater 22.

When the nanofiber diameter is further reduced while increasing the production amount of nanofiber per hour, the rotational speed of the helical screw 30 is increased by the drive motor 31 and the injection flow rate of the thermoplastic resin is increased. At the same time, in order to maintain the thermoplastic resin in a molten state, the heating amount per hour of the band heaters 32A, B, C, D is increased accordingly. On the other hand, in order to further promote the stretching of the thermoplastic resin, the air injection flow rate is increased by the air air compressor 16 more than the amount commensurate with the increase in the injection flow rate of the thermoplastic resin. Since the air is further cooled by air to cause a decrease in viscosity, the air is further heated by the band heater 22.

In particular, in the air heating stage, the air is allowed to be stretched in a state in which the filamentous thermoplastic resin is maintained in a molten state in anticipation of a decrease in the temperature of the air before the flow of the thermoplastic resin is involved. The heating stage of the air may be heated, and the air is heated so that the thermoplastic resin is re-melted at the time of entrainment in anticipation of the temperature of the thermoplastic resin decreasing before being entrained in the air. It's okay.
Therefore, in the air heating stage, depending on the air injection speed, the temperature of the air decreases before the thermoplastic resin flow is involved, and / or the air injection speed depends on the thermoplastic resin injection speed. It is preferable to determine the target temperature of the air in anticipation of a decrease in the temperature of the thermoplastic resin before being caught, and to heat the air so that the air reaches the target temperature.

Below, 2nd Embodiment of this invention is described, referring FIG. 7 and FIG. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Hereinafter, the characteristic portions of the present embodiment will be described in detail.
The feature of this embodiment is that the nanofiber-forming jet nozzle head 12 is provided with a configuration of a divergent nozzle 48 and a temperature sensor.
More specifically, regarding the form of the divergent nozzle 48, in the first embodiment, the shape of the peripheral edge of the widest opening of the divergent nozzle 48 is cylindrical, whereas in the present embodiment, this is the case. The overall shape of the divergent nozzle 48 is a complete frustoconical shape.

Thereby, depending on the air injection amount, it is possible to suppress the diffusion range in the injection direction of the air flow injected from the single air injection port 44, and the thermoplastic resin is drawn into the air flow and stretched. Therefore, when the nanofibers are collected and collected by the collection unit 50, it is possible to limit the spread range of the flying nanofibers in the collection unit 50 to facilitate the collection.

With respect to the temperature sensor, as shown in FIG. 8, a sensor hole 37 is provided in the upper part of the peripheral side surface 56 of the nanofiber-forming injection nozzle head 12, and the temperature sensor is arranged there, and the thermoplastic resin injection holes 42A to 42E. The temperature of the thermoplastic resin immediately before spraying from each is detected, and the amount of the thermoplastic resin necessary for stretching is adjusted by adjusting the heating amount by the band type heater 32 based on the detected temperature of the thermoplastic resin. It is possible to achieve the minimum viscosity more accurately, thereby suppressing the power consumption of the band heater 32. The depth of the sensor hole 37 may be determined from such a viewpoint.

Below, 3rd Embodiment of this invention is described, referring FIG. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Hereinafter, the characteristic portions of the present embodiment will be described in detail.
The feature of this embodiment is in the aspect of the thermoplastic resin injection port 42 in the injection nozzle head 12 for forming nanofibers. More specifically, the thermoplastic resin injection ports 42A to 42E are arranged around the single air injection port 44 in a concentric manner with the single air injection port 44 as the center, in the first and second embodiments. Although it is the same as a form, it has the point which arrange | positions a thermoplastic resin injection port in 2 layers.

Specifically, as shown in FIG. 9, the thermoplastic resin injection ports 42F to 42J are similarly concentrically around the single air injection port 44 around the thermoplastic resin injection ports 42A to 42E. It is arranged. In this case, the inner one-layer thermoplastic resin injection ports 42A to 42E and the outer one-layer thermoplastic resin injection ports 42F to J are alternately arranged, so that, for example, thermoplastic resin injection The thermoplastic resin injected from the port 42A and the thermoplastic resin injected from the thermoplastic resin injection port 42F are brought into contact with each other and do not coalesce before being caught in the air flow. As a modified example, when it is possible to secure a sufficient radial distance between the inner one-layer thermoplastic resin injection ports 42A to 42E and the outer one-layer thermoplastic resin injection ports 42F to 42J, they are alternately changed. There is no need to place them. For each of the thermoplastic resin injection ports 42F to 42J, a through hole 58 for thermoplastic resin that communicates with the thermoplastic resin reservoir portion 62 is provided in the same manner as the thermoplastic resin injection ports 42A to 42E.
With respect to the interval between the thermoplastic resin injection ports 42F to 42J and the single air injection port 44, the thermoplastic resin injected from each of the thermoplastic resin injection ports 42F to 42J is involved in the air flow injected from the single air injection port 44. Therefore, as long as it is set so as to be stretched, the thermoplastic resin injection ports 42A to 42J can be individually used for the thermoplastic resin injection ports 42A to 42J by sharing the single air injection port 44. Compared with the case where an air injection port is provided, it is possible to significantly reduce the amount of air necessary for nanofiber formation.

  As a modification, as shown in FIG. 10, among the two layers of thermoplastic resin injection ports, the inner one layer of thermoplastic resin injection ports may be provided in the divergent nozzle 48. That is, the divergent nozzle 48 is the same as the first embodiment in that the single air injection port 44 is the most contracted diameter opening, but is not in the shape of a frustoconical shape but a cylindrical portion 72 having a reduced diameter D6, and an enlarged diameter. The annular shoulder portion 76 is provided at the boundary between the cylindrical portion 72 and the cylindrical portion 74, and one inner layer thermoplastic resin injection port is disposed on the annular shoulder portion 76. In this case, the radial distance between the single air injection port 44 and the inner layer of the thermoplastic resin injection port is such that the flow of air injected from the single air injection port 44 is the inner layer of the thermoplastic resin injection. If it is set so that the flow of the thermoplastic resin injected from the thermoplastic resin injection port of the inner one layer does not reach the port 42 and can be entrained with respect to the flow of air injected from the single air injection port 44 Good.

Below, 4th Embodiment of this invention is described, referring FIG. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Hereinafter, the characteristic portions of the present embodiment will be described in detail.
The feature of this embodiment is the arrangement of the thermoplastic resin injection ports 42 in the nanofiber forming injection nozzle head 12. More specifically, the thermoplastic resin injection ports 42A to 42E are arranged around the single air injection port 44 in a concentric manner with the single air injection port 44 as the center, in the first and second embodiments. Although it is the same as the form, the thermoplastic resin injection port is arranged on the inclined circumferential surface of the divergent nozzle 48.

More specifically, the divergent nozzle 48 is similar to the first embodiment in that it has a truncated conical shape with the single air injection port 44 as the most contracted diameter opening, but as in the first embodiment, The plastic resin injection port 42 is disposed on the inclined peripheral surface of the divergent nozzle 48 instead of on the facing end surface 54A. In this case, the radial distance between the single air injection port 44 and the thermoplastic resin injection port 42 is such that the flow of air injected from the single air injection port 44 does not reach the thermoplastic resin injection port 42, and What is necessary is just to set so that the flow of the thermoplastic resin injected from the plastic resin injection port 42 can be entangled with the flow of air injected from the single air injection port 44.

Below, 5th Embodiment of this invention is described, referring FIG. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Hereinafter, the characteristic portions of the present embodiment will be described in detail.
The feature of this embodiment is the shape of the divergent nozzle 48 in the nanofiber-forming jet nozzle head 12. More specifically, in the first embodiment, the divergent nozzle 48 has a frustoconical shape with the single air injection port 44 as the most reduced diameter opening, but in the present embodiment, the divergent nozzle 48 has a cylindrical shape with a diameter D5. Yes. In this case, the diameter D5 is set from the single air injection port 44 so that the flow of the thermoplastic resin injected from the thermoplastic resin injection port 42 can be entangled with the air flow injected from the single air injection port 44. What is necessary is just to set so that the flow of the air to be injected may not reach the cylindrical inner peripheral surface until it jumps out from the largest diameter opening 50.

The present applicant has confirmed that nanofibers can be produced using a thermoplastic resin and the nanofiber production apparatus and nanofiber production method according to the present invention.
(1) Test conditions (a) Material: Thermoplastic resin (polypropylene)
Lyonbellbasell PWH00N
(B) Nanofiber manufacturing apparatus According to the nanofiber manufacturing apparatus (FIGS. 1 to 5) of the first embodiment.
(I) Resin side condition (a) Resin flow path (reference number 58 in FIG. 6)
(A) Injection port diameter: 0.4 mm (reference numeral 42 in FIG. 6)
(B) Channel diameter: 3 mm (b) Screw rotation speed:
A motor (ZNHM05-1280-AV-30 / J2ATRA) manufactured by Sumitomo Heavy Industries Gear Motor Co., Ltd. is operated at 25 Hz by inverter control (c) Heating temperature (barrel surface temperature):
260 ° C (heater 32A in Fig. 2)
280 ° C (heater 32B and heater 32C in Fig. 2)
420 ° C (heater 32D in Fig. 2)
(Ii) Air side (d) Air flow path (reference number 60 in FIG. 6)
(C) Injection port diameter: 2 mm (reference number 46 in FIG. 6)
(D) Channel diameter: 4 mm (e) Injection port diameter: 2 mm (f) Discharge pressure: 0.13 MPa
(G) Heating temperature (surface temperature of air carrier tube): 600 ° C
(Iii) Other specifications (h) Reference number D1: 11.5 mm (i) in FIG. 6 Reference number D2 in FIG. 6: 13 mm (j) Diameter of the most enlarged opening in FIG. 6: 22 mm

(2) Test method (c) Nanofiber manufacturing method Higher than the injection speed of the thermoplastic resin so as to entrain the flow of the thermoplastic resin while injecting the thermoplastic resin heated and melted to a predetermined viscosity or less into a thread shape Injecting air heated to a temperature higher than the melting temperature of the thermoplastic resin in parallel with the injection direction of the thermoplastic resin at an injection speed, thereby causing a high-speed central flow region along the injection direction; A peripheral flow region that is slower than the central flow region is generated around it, and the thread-like thermoplastic resin maintained in a molten state is gradually wound from the outer periphery of the peripheral flow region toward the central flow region, The nanofibers that have been drawn and formed in the air are received and collected.
(D) Measuring method of nanofiber diameter By Hitachi scanning electron microscope (SU1510).

(3) Test result The production amount of the nanofiber was 3 Kg / hr.
The measurement results of the nanofiber diameter are shown in FIG. 13 and FIG.
As shown in FIG. 13, it can be seen that the collected nanofibers are appropriately entangled and do not have short fibers or particles.
As shown in FIG. 14, the nanofiber diameter was 86.2 nm, and it was confirmed that nanofibers of 100 nm or less could be produced.
Based on the above results, it has been confirmed from this test result that although it is a simple and compact nanofiber manufacturing apparatus, it is possible to reduce the diameter while securing the production amount without causing shortening or particle formation. .

The embodiments of the present invention have been described in detail above, but various modifications or changes can be made by those skilled in the art without departing from the scope of the present invention.
For example, in the present embodiment, the raw material of the nanofiber has been described as a thermoplastic resin, but is not limited thereto, and the melted and heated raw material is jetted and entrained in a flow of high-speed air, and can be stretched. As long as it is, it can be applied to polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, polypeptide and the like and copolymers thereof.

For example, in this embodiment, regarding the shape and arrangement of a plurality of thermoplastic resin injection ports and a single air injection port, both the thermoplastic resin injection port and the single air injection port are circular openings, and a plurality of thermoplastic resin injections The diameters of all the nozzles are the same, and the angular intervals of the thermoplastic resin injection holes adjacent to each other in the circumferential direction are all assumed to be the same, but the specification required for nanofibers can be achieved without being limited thereto. As long as it is not a circular opening, it may be a non-circular opening, for example, a rectangular opening or an annular opening, and the diameter and angular interval of the thermoplastic resin injection port may be set appropriately.

For example, in the present embodiment, when the plurality of thermoplastic resin injection ports are arranged concentrically around the air injection port, the air flow path is arranged below the nozzle head. Although it was described as an equal angular interval over the angular range of the circumferential semicircle, the present invention is not limited to this, and the nozzle head may be disposed over the circumferential direction of 360 degrees.

For example, in the present embodiment, one kind of bead-shaped thermoplastic resin material has been described as being heated and melted during kneading, but the present invention is not limited thereto, and the molten thermoplastic resin is injected from the injection port. A plurality of types of thermoplastic resin raw materials may be used as long as injection is possible.
For example, in the present embodiment, the nanofiber product has been described as a thread-like long fiber (filament yarn), but is not limited thereto, and is a two-dimensional (planarized) product form of film, woven fabric, Non-woven fabrics, knitted fabrics, three-dimensional (three-dimensional) product forms, three-dimensional molded products, three-dimensional woven fabrics, knitted fabrics, braids, etc. It can also be used for spinning as a polymer combined with microorganisms.

For example, in the present embodiment, the air injection nozzle has been described as a normal nozzle. However, the present invention is not limited thereto, and a subsonic or supersonic air injection speed is used to draw and stretch the nanofiber material. A Laval nozzle may be employed to accomplish this.

1 is an overall configuration diagram of a nanofiber manufacturing apparatus 10 according to a first embodiment of the present invention. 1 is an overall view of a nanofiber manufacturing apparatus 10 according to a first embodiment of the present invention. It is sectional drawing of the injection nozzle head 12 for nanofiber formation of the nanofiber manufacturing apparatus 10 which concerns on 1st Embodiment of this invention. 1 is an end view of a nanofiber forming jet nozzle head 12 of a nanofiber manufacturing apparatus 10 according to a first embodiment of the present invention. 1 is an end view of a nanofiber forming jet nozzle head 12 of a nanofiber manufacturing apparatus 10 according to a first embodiment of the present invention. It is a conceptual diagram which shows the interaction of the thermoplastic resin and the air which are injected from the injection nozzle head 12 for nanofiber formation of the nanofiber manufacturing apparatus 10 which concerns on 1st Embodiment of this invention. It is sectional drawing of the injection nozzle head 12 for nanofiber formation of the nanofiber manufacturing apparatus 10 which concerns on 2nd Embodiment of this invention, and is a figure similar to FIG. FIG. 8 is a partial cross-sectional view taken along line AA in FIG. 7. FIG. 6 is an end view of a nanofiber forming spray nozzle head 12 of a nanofiber manufacturing apparatus 10 according to a third embodiment of the present invention, and is a view similar to FIG. 5. It is a modification of the injection nozzle head 12 for nanofiber formation of the nanofiber manufacturing apparatus 10 which concerns on 3rd Embodiment of this invention, and is a figure similar to FIG. It is sectional drawing of the injection nozzle head 12 for nanofiber formation of the nanofiber manufacturing apparatus 10 which concerns on 4th Embodiment of this invention, and is a figure similar to FIG. It is sectional drawing of the injection nozzle head 12 for nanofiber formation of the nanofiber manufacturing apparatus 10 which concerns on 5th Embodiment of this invention, and is a figure similar to FIG. It is a microscope picture of the nanofiber manufactured using the nanofiber manufacturing apparatus concerning a 1st embodiment of the present invention. It is the elements on larger scale of FIG. 13, and is a microscope picture which shows the diameter of nanofiber. It is a control block diagram of the nanofiber manufacturing apparatus 10 which concerns on 1st Embodiment of this invention.

α Wide angle
A High-speed air center flow area
B Low-speed air flow area
C Thermoplastic flow
D1 Injection direction distance between thermoplastic resin injection port and single air injection port
D2 Radial distance between thermoplastic injection port and single air injection port
D3 Extension area
D5 Diameter of the largest diameter opening
D6 Diameter of reduced diameter cylindrical part
Z1 to Z5 Barrel temperature range 10 Nanofiber production apparatus 12 Nanofiber forming injection nozzle head 14 Thermoplastic resin supply unit 16 Air supply unit 18 Resin heating unit 20 Resin kneading and conveying unit 22 Air heating unit 24 Air pressure feeding unit 26 Kneading and conveying space 28 Hopper 30 Spiral screw 31 Motor 32 Band heater 33 Spiral blade 34 Cleaning liquid supply unit 35 Cooling device 36 Resin temperature detection means 37 Temperature sensor installation hole 42 Thermoplastic resin injection port 44 Single air injection port 46 Smallest diameter opening 48 Widest nozzle 50 Largest diameter opening 52 Nozzle peripheral end 54 Opposing end surface 55 Tapered portion 56 Peripheral side surface 57 Screw hole 58 Through hole 59 for thermoplastic resin Reduced diameter portion 60 Through hole 61 for air Large diameter portion 62 Thermoplastic resin Pool portion 72 Reduced diameter cylindrical portion 74 Expanded diameter cylindrical portion 76 Annular shoulder 80 Heatable RESIN temperature detecting means 82 thermoplastic resin flow rate detecting unit 84 air temperature detecting means 86 air flow rate detecting unit 88 control unit

Claims (12)

A plurality of polymer material injection ports for injecting a molten polymer material having a predetermined viscosity or less, and at least air heated to a temperature higher than the temperature of the polymer material in the molten state, based on at least the injection speed of the polymer material in the molten state A single air injection port that injects in the same direction as the injection direction of the molten polymer material at high speed,
The plurality of macromolecules so that the polymer material in a molten state ejected from each of the plurality of polymer material ejection ports is caught in a flow of air ejected from the single air ejection port and extends in the ejection direction. An injection nozzle head for forming nanofibers, wherein a material injection port is provided around the single air injection port and downstream from the single air injection port in the injection direction. The plurality of polymer material injection ports are concentrically arranged around the single air injection port, and the polymer material injection ports adjacent in the circumferential direction are spaced apart from each other by a predetermined angle. 2. An injection nozzle head for forming nanofibers according to 1. The nanofiber forming injection nozzle head is a monolithic solid body having opposing end faces and a peripheral side face between the opposing end faces,
The plurality of polymer material injection ports and the widest diameter opening of the divergent nozzle are formed on one end surface of the opposed end surfaces,
In the monolithic solid body, one end opening forms the polymer material injection opening, and a polymer material through-hole forming a flow path of the polymer material is provided, and one end opening is the single opening. An air through hole is formed, forming an air injection opening and constituting an air flow path,
The divergent nozzle is configured as a through passage that communicates with the other end opening of the air through hole and extends toward one end face of the opposing end face,
The other end opening of the through hole for polymer material is provided on the other end surface of the opposed end surface, and the through hole for polymer material extends in the longitudinal direction of the monolithic solid body,
The other end opening of the air through hole is provided on the peripheral side surface, and the polymer material through hole has a portion extending in a direction intersecting with a longitudinal direction of the monolithic solid body. The nanofiber-forming jet nozzle head as described. On the other end face of the opposing end face, a hollow polymer material reservoir is formed,
4. The nanofiber-forming jet nozzle head according to claim 3, wherein each of the polymer material through holes communicates with the polymer material reservoir. An injection nozzle head for forming nanofibers according to any one of claims 1 to 4,
A polymer material supply unit for supplying a polymer material toward the nanofiber-forming jet nozzle head;
An air supply unit that supplies air toward the nanofiber-forming injection nozzle head;
The polymer material supply unit includes a polymer material heating unit and a polymer material kneading and conveying unit.
The said air supply part has a heating means of air, and a pressure sending means of air, The nanofiber manufacturing apparatus characterized by the above-mentioned. The polymer material supply unit includes a cylindrical body that constitutes a kneading and conveying space for the polymeric material therein, and the cylindrical body is provided with an inlet for receiving a bead-shaped polymeric material raw material. In the space, a spiral screw for kneading and conveying the bead-shaped polymer material raw material is arranged,
A band heater is wound around the outer peripheral surface of the nanofiber-forming spray nozzle head and the outer peripheral surface of the portion corresponding to the kneading and conveying space of the cylindrical body,
The nanofiber-forming injection nozzle head has the other end face abutted against the end face of the cylindrical body so that the axial direction thereof coincides with the axial direction of the helical screw. The nanofiber manufacturing apparatus according to claim 5, which is provided in the apparatus.   Further, a cleaning liquid supply unit for cleaning the plurality of polymer material through holes is provided, and the cleaning liquid supply unit is provided from the other end opening of each of the plurality of polymer material through holes to one end opening. The nanofiber manufacturing apparatus according to claim 6, wherein the cleaning liquid is supplied to the inside. Furthermore, it has an external air conveyance pipe connected so as to be able to communicate with the other end opening of the air through hole,
The air heating means is a band-type air heater wound around the outer peripheral surface of the air pressure feeding means and the external air conveyance pipe,
The nanofiber manufacturing apparatus according to claim 6, wherein the air pressure feeding means is an air air compressor connected to an end of the external air conveyance pipe. Further, a polymer material temperature detecting means for detecting the temperature of the polymer material in the kneading and conveying space, and a flow rate of the polymer material kneaded and conveyed from the kneading and conveying space toward the plurality of polymer material through holes. A polymeric material flow rate detecting means for detecting air temperature detecting means for detecting the temperature of air in the air flow path, and an air flow rate detecting means for detecting the flow rate of air in the air flow path,
Based on the temperature of the polymer material detected by the polymer material temperature detection means and the flow rate of the polymer material detected by the polymer material flow rate detection means, the heating amount of the band heater and / or the spiral And controlling the number of rotations of the screw and the heating amount of the band-type air heater and / or the temperature of the air detected by the air temperature detecting means and the air flow detected by the air flow detecting means. Or the nanofiber manufacturing apparatus of Claim 5 which has a control part which controls the discharge pressure of the said air air compressor.   The said nanofiber manufacturing apparatus is a nanofiber manufacturing apparatus of Claim 5 which is a portable type with a caster. Each of the through holes for the polymer material connects the enlarged diameter portion communicating with the polymer material reservoir portion, the reduced diameter portion communicating with the polymer material injection port, and the enlarged diameter portion and the reduced diameter portion. The nanofiber manufacturing apparatus according to claim 4, further comprising a tapered portion. 12. The polymer material according to claim 1, wherein the polymer material includes a thermoplastic resin, a thermoplastic elastomer, polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, and a polypeptide. The nanofiber manufacturing apparatus according to Item.

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