JP4831348B2 - Electrospinning apparatus and electrospinning method - Google Patents

Description

  In this invention, a polymer solution is injected from the injection portion at the tip of the storage case toward the collector, and the solution is stretched based on the potential difference to spin ultrafine fibers to produce a web used for a filter or the like. The present invention relates to an electrospinning apparatus and an electrospinning method.

  Conventionally, as this type of electrospinning apparatus, ones having configurations as disclosed in, for example, Patent Document 1 and Patent Document 2 have been proposed. In the conventional apparatus of Patent Document 1, a nozzle for injecting a polymer solution and a barrel for storing the polymer solution are heated with a heating band, and the temperature of the polymer solution in the interior is in a temperature range from 40 ° C. to the boiling point of the solvent or less. To maintain. Further, the relative humidity of the operation space (the space between the nozzle and the barrel) is adjusted to a predetermined value (for example, 25%), and spinning is performed in this state.

In the conventional apparatus disclosed in Patent Document 2, air is jetted from an air nozzle toward a yarn discharging nozzle from which a polymer solution is discharged during spinning.
JP 2002-249966 A (paragraph 0052 and [Summary] in the detailed description of the invention) Japanese translation of PCT publication No. 2005-520068 (paragraph 0013 in FIG. 2 and FIG. 2)

However, these conventional electrospinning apparatuses have the following problems.
First, in the conventional apparatus of Patent Document 1, the entire storage case and the nozzle are heated. For this reason, the heating time for the polymer solution is long, and it is difficult to spin ultrafine fibers using a polymer solution that is unstable to heat and easily deteriorates. Therefore, the type of polymer that can be used is limited, and it is not possible to deal with many types of polymers. In addition, when the polymer solution is heated in the storage case, the viscosity of the polymer solution decreases. Therefore, when spinning with a fine powder of a functional material (for example, activated carbon or ceramic) mixed in the polymer solution, Aggregation tends to occur, and it has been difficult to spin a fiber containing a functional material in a uniform dispersed state. Furthermore, there is a possibility that the nozzle is clogged due to aggregation of the fine powder.

  On the other hand, in the conventional apparatus of Patent Document 2, since heated air is blown to the polymer solution discharged from the yarn discharging nozzle, volatilization of the solvent is promoted. As a result, the viscosity of the drawn polymer solution became high, making it difficult to stretch the drawn yarn, thickening the drawn fiber, and spinning the ultrafine fiber. In addition, since the polymer solution flies unstably by blowing heated air, it is difficult to produce a fiber layer having an intended uniform density. In addition, since the solvent of the polymer solution is easily volatilized by the heated air, there is a possibility that a lump of polymer is formed around the yarn output nozzle and the surrounding area. And when a lump is produced in this way, the heated air flow is further disturbed by this lump or the lump becomes an obstacle to spinning, and high-quality spinning is difficult.

  The present invention has been made paying attention to such problems existing in the prior art. The main object of the present invention is to make it possible to produce a web of ultrafine fibers by sufficiently stretching the polymer solution.

  Another object of the present invention is to make it possible to produce a fiber in which a functional material is uniformly dispersed by suppressing aggregation of the fine powder even when a fine powder such as a functional material is mixed in the polymer solution. Is to make it.

In order to achieve the above object, an invention relating to an electrospinning apparatus is based on a potential difference by injecting a polymer solution from a needle as an injection unit provided at the tip of a syringe pump as a storage case toward a collector. In the electrospinning apparatus configured to perform spinning, the polymer solution in the tip of the needle is heated to a temperature higher than the polymer solution in the syringe pump and lower than the boiling point of the solvent of the polymer solution. The heating means is provided at the tip of the needle .

  Therefore, in the electrospinning apparatus of the present invention, since only the injection section is locally heated, heating of the polymer solution in the storage state can be suppressed as compared with the conventional apparatus in which the storage case is heated. For this reason, it becomes possible to spin ultrafine fibers using a polymer solution that is easily altered by heat. Furthermore, since the polymer solution is not heated in the storage case, even when a fine powder such as a functional material is mixed in the polymer solution for spinning, the decrease in viscosity due to the heating of the polymer solution can be prevented, and the aggregation of the fine powder is suppressed. it can. For this reason, the fiber which disperse | distributed the functional material uniformly can be produced. In addition, there is no possibility of clogging of the injection part due to the aggregation of the fine powder during spinning.

Moreover, the said structure WHEREIN: The said heating means is good to comprise from the heater provided in the outer periphery of the said injection | pouring part.
Furthermore, in the said structure, while forming the said injection | emission part with a metal, a voltage is applied to the injection | emission part, and also it is good for an injection | emission part to be supported by the said storage case via a heat insulating material. When comprised in this way, even if it comprises an injection | emission part with a metal, it can prevent that a heat | fever is transmitted to the storage case side.

  Furthermore, in the above-described configuration, the injection portion may be formed integrally with a storage case made of an insulating material, and an electrode for forming a potential difference may be provided inside the storage case. In such a configuration, since the thermal conductivity of the storage case is low, it is possible to suppress heat from being transferred from the injection part to the storage case side without using a heat insulating material as described above. .

  Furthermore, in the above configuration, it is preferable to provide a cooling means for cooling the polymer solution in the storage case. When comprised in this way, the heating of the polymer solution in a storage case can be suppressed effectively.

In the above configuration, the outer shell of the heater may be formed of an insulating material. In this way, leakage through the outer shell of the heater can be prevented.
Furthermore, in the said structure, it is good to make the front-end | tip of the said injection | emission part project to the collector side rather than a heater. Even if comprised in this way, the polymer solution inject | emitted from an injection | emission part can be appropriately threaded toward a collector.

The invention relating to the electrospinning method is an electrospinning method in which spinning is performed based on a potential difference by injecting a polymer solution from a needle as an injection unit provided at a tip of a syringe pump as a storage case toward a collector. In the method, the polymer solution in the tip of the needle is heated to a temperature higher than that of the polymer solution in the syringe pump and lower than the boiling point of the solvent of the polymer solution.

  As described above, according to the present invention, it is possible to deal with various types of polymers, and exhibit excellent effects such as the ability to efficiently produce webs made of ultrafine fibers.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, a collector 12 made of a metal roller such as stainless steel or aluminum alloy is supported in the housing 11 and is continuously rotated in one direction by a motor (not shown). In the housing 11, a syringe pump 13 as a storage case made of an insulating material such as glass is opposed to the side of the collector 12, and a polymer solution 14 is accommodated in the syringe pump 13. A needle 15 as an injection portion made of metal for injecting the polymer solution 14 is attached to the tip of the syringe pump 13. Then, the polymer solution 14 in the syringe pump 13 is ejected from the tip opening of the needle 15 toward the collector 12. A power source 16 is connected to the needle 15 and a high voltage is applied to charge the polymer solution 14. The collector 12 is grounded. Therefore, a potential difference is given between the needle 15 and the collector 12 through a space. The polymer solution 14 injected from the tip 15a of the needle 15 is extracted based on the potential difference and electrospun.

One or a plurality of syringe pumps 13 are installed. In the case of a plurality of syringe pumps 13, the syringe pumps 13 are installed along the axial direction of the collector 12 at intervals in a direction perpendicular to the paper surface of FIG.
On the outer side of the housing 11, a feeding roller 18 for feeding the spinning base material 17 such as filter paper or nonwoven fabric to the outer periphery of the collector 12 in the housing 11 is disposed. Then, the polymer solution 14 from the needle 15 is spun and accumulated on the surface of the spinning base material 17 circulated around the outer periphery of the collector 12, thereby forming a web-like fiber layer 19 made of ultrafine fibers. Therefore, on the collector 12, the fiber laminated body 20 which consists of the said spinning base material 17 and the fiber layer 19 of the surface is produced. A winding roller 21 is disposed on the outer side of the housing 11, and the fiber laminate 20 is wound around the winding roller 21 via a guide roller 22.

  As shown in FIG. 2, a heater 23 as a heating means is provided on the outer periphery of the tip portion 15a of the needle 15 over almost the entire length of the tip portion 15a. The heater 23 is configured by containing heating oil 25 in a container 24 as an outer shell made of a hollow annular insulating material. The heater 23 heats the polymer solution 14 in the tip portion 15a of the needle 15 to a temperature higher than that of other portions and lower than the boiling point of the solvent of the polymer solution 14. Here, the heating oil 25 is circulated between a heat source (not shown) and the inside of the container 24. And although the heating temperature with respect to the polymer solution 14 is set according to the kind of the polymer solution 14, it is preferable to set about 10-30 degreeC lower than the boiling point of the solvent of the polymer solution 14. FIG.

  When spinning from the polymer solution 14 for a filter, the polymer solution 14 may be a water-insoluble polymer such as polyethylene terephthalate or nylon, or a water-soluble polymer or polymer such as polyvinyl alcohol. There are biodegradable polymers such as proteins such as lactic acid and gelatin, and polysaccharides such as starch. Examples of the solvent for these polymers include formic acid, dimethylformaside, dichloromethane, chloroform, water, or a mixed solvent of water and alcohol.

  An annular heat insulating material 26 is interposed between the outer periphery of the distal end of the syringe pump 13 and the inner periphery of the proximal end of the needle 15. And the needle 15 is supported by the front-end | tip of the syringe pump 13 via this heat insulating material 26, For this reason, transmission of the heat | fever from the needle 15 to the syringe pump 13 side is suppressed.

The tip of the needle 15 protrudes from the end face of the heater 23 toward the collector 12.
Next, the operation of the electrospinning apparatus configured as described above will be described.

  When the electrospinning apparatus is operated, the spinning base material 17 is fed out from the feeding roller 18 by the rotation of the collector 12 and is circulated around the outer periphery of the collector 12. At this time, the polymer solution 14 is injected from the tip 15 a of the needle 15 toward the spinning substrate 17 on the outer periphery of the collector 12. The injected polymer solution 14 flies while being spun based on the potential difference between the needle 15 and the collector 12, and a web-like fiber layer 19 is formed on the surface of the base material 17 by spinning. By forming the fiber layer 19, a fiber laminate 20 is produced, and the fiber laminate 20 is taken up by the take-up roller 21 via the guide roller 22.

Here, this embodiment has the following effects.
(1) When the polymer solution 14 is ejected from the needle 15, the heater 23 causes the polymer solution 14 only at the tip 15 a of the needle 15 to be higher in temperature than the polymer solution 14 in other portions and the boiling point of the solvent of the polymer solution 14. Heat to the following temperature. For this reason, the viscosity of the polymer solution 14 inject | emitted from the front-end | tip part 15a can be reduced. Accordingly, the injected polymer solution 14 can be stretched thinly to form a fiber layer 19 of ultrafine fibers. For this reason, when the fiber laminated body 20 which has this fiber layer 19 is used as a filter, the eyes between the fibers of the fiber layer 19 can be made fine, without reducing the porosity of a filter significantly. Therefore, a function capable of effectively filtering fine dust and the like can be imparted to the filter in spite of low pressure loss.

(2) Moreover, since no air flow is used for spinning, the fiber layer 19 is formed so that the ultrafine fibers have a uniform density.
(3) Since the heat insulating material 26 is interposed between the proximal end inner periphery of the needle 15 and the distal end outer periphery of the syringe pump 13, it is possible to suppress the heat of the needle 15 from being transmitted to the syringe pump 13 side. Therefore, even the polymer solution 14 that is unstable to heat and easily deteriorates can be used to spin ultrafine fibers. For this reason, the kind of polymer solution which can be used for spinning can be increased.

  (4) Since the heating of the polymer solution 14 in the syringe pump 13 can be suppressed, the polymer solution 14 in the pump 13 can be maintained at a high viscosity. Therefore, even when a fine powder such as a functional material is mixed in the polymer solution 14 for spinning, there is almost no risk of the fine powder agglomerating due to a decrease in the viscosity of the polymer solution 14. Therefore, the functional material can be contained in a uniformly dispersed state, and the fiber layer 19 that can effectively exhibit the function of the functional material can be formed. Moreover, since aggregation of fine powder can be suppressed, the possibility of clogging of the needle 15 can also be prevented.

  (5) Since the viscosity of the polymer solution 14 injected during spinning can be lowered and the polymer solution 14 can be effectively extended, the formation of a lump of the polymer solution 14 at the tip of the needle 15 is prevented. it can. For this reason, spinning can be performed smoothly without being disturbed by a lump or the like, and it becomes possible to spin ultrafine fibers at a uniform density.

(6) Since the polymer solution 14 is heated at the thin needle 15 portion, the amount of heat required for the heating is very small, and an energy saving operation is possible.
(7) Since the container 24 of the heater 23 is formed of an insulating material, unlike the case of being formed of metal, not only is the amount of wasteful heat radiation reduced, but also leakage current is generated through the container 24. Can be prevented.

  (8) Since the tip of the needle 15 protrudes toward the collector 12 from the heater 23, discharge between a part of the heater 23 and the collector 12 can be prevented. That is, even if the container 24 constituting the outer shell of the heater 23 is made of an insulating material, a current may flow on the surface of the heater 23. In such a case, when the heater 23 protrudes toward the collector 12, a potential difference is generated between the outer surface of the heater 23 and the tip of the needle 15, and the polymer solution 14 from the tip of the needle 15 is transferred to the outer surface of the heater 23. There is a risk that the yarn will be output via. Thus, when the yarn is drawn toward the outer surface of the heater 23, a lump of polymer or the like is formed on the outer surface of the heater 23. In this embodiment, such a concern does not occur.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following embodiments and modifications, the description will focus on the parts that are different from the first embodiment.

  In the second embodiment, as shown in FIG. 3, the syringe pump 13 is made of an insulating material such as glass, and a needle 13 a as an injection portion is integrally formed at the tip of the syringe pump 13. Yes. A heater 23 is provided on the outer periphery of the needle 13a so as to extend from the tip portion to the vicinity of the intermediate portion. An electrode 31 for forming a potential difference is disposed inside the syringe pump 13, and charges are applied to the polymer solution 14 by the electrode 31.

  Therefore, in the second embodiment, since the syringe pump 13 is made of an insulating material such as glass whose thermal conductivity is lower than that of metal, unlike the first embodiment, a heat insulating material is not used. Moreover, it can suppress that heat is transmitted from the needle 13a to the syringe pump 13 side.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
In the third embodiment, as shown in FIG. 4, the peripheral wall of the syringe pump 13 is formed by an inner wall portion 32 and an outer wall portion 33 so as to form a jacket structure. And between the inner wall part 32 and the outer wall part 33 of this syringe pump 13, the cooling water 34 for cooling the polymer solution 14 in the syringe pump 13 is accommodated. The cooling water 34 is circulated between a cooling source (not shown) and maintained at a constant temperature.

  Therefore, in the third embodiment, the heating of the polymer solution 14 in the syringe pump 13 can be positively suppressed by the cooling water 34 inside the jacket structure constituting the cooling means. Therefore, it is particularly effective for spinning a polymer solution that is easily altered by heat or a polymer solution mixed with fine powder.

(Fourth embodiment)
Next, a fourth embodiment will be described.
In the fourth embodiment, as shown in FIG. 5, when the needle 15 is made of metal, the tip of the needle 15 is sharpened so that the inner peripheral side of the tip of the needle 15 protrudes toward the collector 12 side. Is formed.

  Therefore, in the fourth embodiment, since the tip of the needle 15 is separated from the container 24 of the heater 23, the polymer solution 14 from the tip of the needle 15 can be effectively threaded toward the collector 12.

(Fifth embodiment)
Next, a fifth embodiment will be described.
In the fifth embodiment, as shown in FIG. 6, the collector 12 is composed of a pair of rollers 27 and an endless belt 28 made of a thin metal plate spanned between the rollers 27. The endless belt 28 is connected to the ground. The needle 15 faces the endless belt 28 between the rollers 27, and spinning is performed on the spinning base material 17 on the endless belt 28 between the rollers 27.

Accordingly, in the fifth embodiment, since spinning is performed on the spinning base material 17 in a flat state, the fiber layer 19 can be smoothly and smoothly performed along the surface of the spinning base material 17.
(Example of change)
In addition, this embodiment can also be changed and embodied as follows.

  As shown in FIG. 7, a plurality of syringe pumps 13 are attached to the housing 11 such that only the needles 15 at the tips thereof protrude into the housing 11, and the internal space is heated in the housing 11. And the heating apparatus 35 for maintaining each needle 15 at predetermined temperature is provided. If comprised in this way, it is not necessary to provide a heating means in the syringe pump 13.

In each of the above embodiments, a different configuration such as a heat band is used as a heating means for heating the needle 15.
In the first and third embodiments, the needle 15 itself is constituted by a heater as heating means. In this case, for example, a ceramic heater such as a barium titanate ceramic can be used.

Sectional drawing which shows the electrospinning apparatus of 1st Embodiment. FIG. 2 is an essential part cross-sectional view showing an enlarged needle portion in the electrospinning apparatus of FIG. 1. The principal part sectional view showing the needle part in a 2nd embodiment. The principal part sectional view showing a needle part in a 3rd embodiment. The principal part sectional view showing a needle part in a 4th embodiment. Sectional drawing which shows the electrospinning apparatus of 5th Embodiment. Sectional drawing which shows the example of a change of an electrospinning apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 ... Collector, 13 ... Syringe pump, 13a ... Injection | emission part, 14 ... Polymer solution, 15 ... Needle, 16 ... Power supply, 23 ... Heater as a heating means, 26 ... Heat insulating material, 31 ... Electrode, 32 ... As a cooling means Inner wall 33, outer wall as cooling means, 35 ... heating device as heating means.

Claims (8)

In an electrospinning apparatus that performs spinning based on a potential difference by injecting a polymer solution from a needle as an injection unit provided at the tip of a syringe pump as a storage case toward a collector,
Heating means for heating the polymer solution in the tip of the needle to a temperature higher than the polymer solution in the syringe pump and below the boiling point of the solvent of the polymer solution is provided at the tip of the needle . An electrospinning apparatus characterized by that. The electrospinning apparatus according to claim 1, wherein the heating unit includes a heater provided on an outer periphery of the injection unit. 3. The electrospinning according to claim 1, wherein the injection part is made of metal, a voltage is applied to the injection part, and the injection part is supported by the storage case via a heat insulating material. apparatus. The electrospinning apparatus according to claim 1 or 2, wherein the injection portion is formed integrally with a storage case made of an insulating material, and an electrode for forming a potential difference is provided inside the storage case. The electrospinning device according to any one of claims 1 to 4, wherein the storage case has a cooling means for cooling the polymer solution. The electrospinning apparatus according to any one of claims 2 to 5, wherein an outer shell of the heater is made of an insulating material. The electrospinning apparatus according to any one of claims 2 to 5, wherein a tip end of the injection portion is protruded toward the collector side with respect to the heater. In an electrospinning method in which spinning is performed based on a potential difference by injecting a polymer solution from a needle as an injection unit provided at the tip of a syringe pump as a storage case toward a collector,
An electrospinning method comprising heating the polymer solution in the tip of the needle to a temperature higher than that of the polymer solution in the syringe pump and lower than the boiling point of the solvent of the polymer solution.

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