JP2009174066A - Spinneret for electrospinning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spinneret for an electrospinning device, not requiring the heightening of voltage to be applied, and capable of dealing with the production of nanofibers having different morphology. <P>SOLUTION: The spinneret for the electrospinning device has a core-side nozzle 3 for ejecting a first solution for forming a core part, and a sheath-side casing 5 detachably attached to the outer periphery of the core-side nozzle 3, having a sheath-side nozzle 5a formed in a protruded state at the distal end and a second solution-feeding path 5b for feeding a second solution for forming a sheath part to the sheath-side nozzle 5a. In the spinneret, when the sheath-side casing 5 is attached to the outer periphery of the core-side nozzle 3, a needle part 3a is coaxially inserted to the inside of the sheath-side nozzle 5a, and the needle part 3a is protruded from the distal end of the sheath-side nozzle 5a. The protruded distance can be changed by regulating the attaching position of the sheath-side casing 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a spinneret (spinneret) for spinning nanofibers having a core-sheath structure or a hollow structure using an electrospinning apparatus.

  Healthcare fields such as regenerative medicine engineering, wound materials, drug delivery, biomolecules and environmental engineering fields such as affinity membranes and sensors for purification of biomolecules and contaminated water, polymer batteries, dye-sensitized sun Less than micron (μm) in energy fields such as batteries, polymer membrane fuel cells, etc., or in a wide range of fields such as composite material reinforcement, protection against bioterrorism, and protection / security such as protective clothing assuming gas attacks A fiber (nanofiber) having a nano-order diameter (for example, several nm to several hundred nm) has attracted attention.

  One technique for producing such nanofibers is the electrospinning method. For example, as disclosed in Patent Document 1, this electrospinning method includes a nozzle that injects a solution of a polymer as a fiber material and a volatile solvent, a flat collector, and a nozzle and a collector. And a high voltage power source for applying a high voltage to the power source.

  In this apparatus, when a solution is pushed out from the spinning nozzle at the tip of the nozzle while a high voltage is applied between the nozzle and the collector, the droplet of the polymer solution at the tip of the spinning nozzle is charged to + (or-), and the different polarity It is attracted by the electrostatic force (Coulomb force) acting along the electric force line toward the collector that is charged (grounded). When the electrostatic force exceeds the surface tension, a spinning jet of polymer solution is continuously jetted toward the collector. At this time, the solvent in the polymer solution is volatilized, and when it reaches the collector, only the polymer fiber is formed, and the nano-fiber is of a nano level. In addition, as a raw material of the nanofiber, not only an organic polymer but also an inorganic material such as a metal oxide or ceramic can be spun into a nanofiber shape by a sol-gel method.

  It is known that a spinning jet ejected from a spinner draws a spiral trajectory due to the influence of the distribution of electric lines of force between the spinneret and the collector while reaching the collector from the spinneret (for example, Non-patent documents 1 and 2). As a result, the nanofibers integrated on the collector are randomly oriented and become non-woven when they are integrated on the collector.

  In order to control this orientation, a cylindrical rotating body collector is used (for example, see Patent Document 2). By using this rotating body collector and winding the spinning jet at a rotational speed faster than the moving speed of the spinning jet, it becomes possible to produce an oriented fiber sample.

  By the way, the nanofiber structure is assumed to be a single fiber, which is the same material as a whole, but on the other hand, a double structure (core-sheath structure) consisting of an inner core and a sheath surrounding it, or the core is hollow The production technology of functional nanofibers having a hollow structure has been studied. The nano-fibers having the core-sheath structure are considered to be used for, for example, regenerative medicine and supply of drugs to the body (drug delivery), but are expected to be used for various purposes in the future.

  When producing a fiber having a core-sheath structure, the spinneret (spinneret) is formed from a central guide hole for discharging the core part and a guide hole on the outer periphery thereof, as described in Patent Documents 3 to 5. It has a structure that discharges various types of materials.

Japanese Patent Laying-Open No. 2005-330624 (paragraphs 0036 to 0040, FIG. 3) JP 2005-264386 A (paragraph 0002, FIG. 1) Japanese Patent Application Laid-Open No. 7-278943 Japanese Patent Laid-Open No. 11-100780 Japanese Patent No. 2540384 A. El. AL Yarin et al., "Bending instability in electrospinning of nanofibers", Journal of Applied Physics, 89, Vol. No. 5, March 1, 2001, p. 3018-3026 A. El. AL Yarin et al., "Taylor cone and jetting from liquid droplets in electrospinning of nanofibers", Journal. Journal of Applied Physics, Volume 90, No. 9, September 1, 2001, p. 4836-4846

  The spinneret structures described in the above-mentioned patent documents 3 to 5 are all used for the flash spinning method in which the solvent is evaporated by discharging a solution obtained by dissolving the core and sheath materials in the solvent at a high speed to obtain ultrafine fibers. There are various problems to apply to the electrospinning method.

  One of them is the problem of the electric field distribution and the direction of the electric lines of force formed between the conductive part near the spinneret and the collector. For example, if the vicinity of the spinning hole of the lower base plate in which the spinning hole is formed as described in Patent Document 4 described above is a flat surface, the lower base plate 20 and the nanofiber are integrated as shown in FIG. In the electric field distribution generated by the voltage applied to the collector 21, the isovoltage line is parallel to the collector 21, and the direction of the electric lines of force is perpendicular to the isovoltage line. If it does so, the spinning jet radiated | emitted from the spinneret of the lower nozzle | cap | die metal plate 20, and will be attracted | sucked by the collector 21 will not become a spiral orbit, and it will become difficult to pull out a fiber with a small diameter. It has been reported that spinning jets are drawn while drawing a spiral trajectory. In other words, in order to spin a nanoscale diameter fiber, drawing this spiral trajectory is one of the important elements.

  In addition, since the lines of electric force in the vicinity of the spinneret are not concentrated at one point, the voltage applied between the lower end metal plate 20 and the collector 21 must be considerably increased. Furthermore, in the conventional spinneret, the diameter and positional relationship between the core-side spinneret and the sheath-side spinneret are fixed, so it is necessary to manufacture the entire spinneret every time the fine fiber material and wire diameter are different. There is a problem that the diameter and fiber form (morphology) cannot be controlled.

  Therefore, the present invention eliminates the need to increase the voltage to be applied when producing nanofibers by applying the electrospinning method. Furthermore, the morphology is different only by exchanging the core side nozzle and the sheath side nozzle. An object of the present invention is to provide a spinneret for an electrospinning apparatus that can be used for the production of nanofibers.

  In order to solve the above-mentioned problems, the present invention provides a spinneret for an electrospinning apparatus for producing a core-sheath fiber structure, and a core-side nozzle that discharges a first solution serving as a core part of the core-sheath fiber structure. And a sheath side nozzle provided on the outer periphery of the core side nozzle, and a sheath side casing forming a second solution supply path for supplying a second solution to the sheath side nozzle, the sheath side casing being the core When attached to the outer periphery of the side nozzle, the core side nozzle is inserted inside the sheath side nozzle, and the core side nozzle protrudes a predetermined length from the tip of the sheath side nozzle. .

  In the present invention, the core side nozzle that discharges the first solution is inserted inside the sheath side nozzle that discharges the second solution, and the tip of the core side nozzle protrudes from the tip of the sheath side nozzle. When a voltage is applied between the spinneret and the collector, the electric force lines toward the collector are concentrated at one point at the sheath side nozzle and the core side nozzle, so that a spinning jet that draws a spiral trajectory is obtained and the wire diameter is thin. Fiber is obtained. Further, the applied voltage can be suppressed to the same level as when a single nozzle having a single structure is used.

  In the present invention, by changing the diameter of the core side nozzle and the sheath side nozzle, or by changing the amount of protrusion of the core side nozzle from the tip of the sheath side nozzle by adjusting the mounting position of the sheath side casing, The morphology of nanofibers can be controlled.

  Further, in the present invention, a core-side casing provided with a core-side nozzle mounting cylinder that detachably mounts the boss portion of the core-side nozzle and supplies the first solution to the core-side nozzle, and an outer periphery of the core-side nozzle By providing a nozzle holder that fixes the core side casing to the core side casing, it becomes easy to replace and fix the core side nozzle.

  According to the present invention, a spinneret for an electrospinning device for producing a core-sheath fiber structure, a core-side nozzle that discharges a first solution serving as a core part of the core-sheath fiber structure, and a core-side nozzle, When the sheath side nozzle provided on the outer periphery and the sheath side casing that forms the second solution supply path for supplying the second solution to the sheath side nozzle are provided, and the sheath side casing is attached to the outer periphery of the core side nozzle, Since the core side nozzle is inserted inside the sheath side nozzle and the core side nozzle protrudes from the tip of the sheath side nozzle by a predetermined length, there is no need to increase the applied voltage. By simply exchanging the side nozzle and the sheath side nozzle, it is possible to cope with the production of nanofibers having different morphologies.

Embodiments of the present invention will be described below with reference to FIGS.
FIG. 1 is a partially cutaway front view showing a configuration of a spinneret for an electrospinning apparatus according to an embodiment of the present invention (hereinafter simply referred to as “spinneret”), FIG. 2 is an enlarged view of a core side nozzle, and FIG. FIG. 4 is a system configuration diagram, and FIG. 4 is an explanatory diagram showing electric field strength and electric lines of force when the spinneret of the present embodiment is used.

  In FIG. 1, reference numeral 1 denotes a base for fixing the spinneret to the apparatus. A core side casing 2 is fixed to the lower surface of the base 1. The base 1 and the core casing 2 are provided with a passage 1a and a passage 2a to which the first solution is supplied, respectively, and both passages 1a and 2a communicate with each other. The core side nozzle 3 is attached to the core side nozzle mounting cylinder 2b at the tip of the core side casing 2 by mounting the boss portion 3b (see FIG. 2) of the core side nozzle 3 including the needle portion 3a and the boss portion 3b. The nozzle holder 4 is screwed into the core side casing 2 so as to hold down the flange portion 3c of the boss portion 3b. Thereby, the core side nozzle 3 is fixed so as not to come out of the core side casing 2. A sheath-side casing 5 formed so that a sheath-side nozzle 5 a protrudes from the tip of the nozzle holder 4 is attached to the outside of the nozzle holder 4 so that the position of the casing-side casing 5 can be adjusted. The sheath side casing 5 is formed with a second solution passage 5b that is supplied so that the second solution is discharged through a gap between the outside of the needle portion 3a and the inside of the sheath side nozzle 5a. Also, a first liquid feeding tube 7 for supplying the first solution and a second liquid feeding tube 8 for supplying the second solution are connected to the passage 1a and the second solution passage 5b through the tube connector 12, respectively. Has been. The base 1 is provided with a connector 9 for connecting a cable from one voltage terminal of the high voltage power supply.

  As shown in FIG. 3, the spinneret having the above configuration is attached to the upper part of a housing (not shown) of the electrospinning apparatus, and is connected between the collector 10 and the connector 9 installed below by a high voltage power supply 11. The generated high voltage (several tens of kV) is applied.

  FIG. 4 shows an electric field distribution (equipotential lines) and electric lines of force due to the applied high voltage at this time. In the present embodiment, since the sheath side nozzle 5a protrudes from the sheath side casing 5, and the needle portion 3a of the core side nozzle 3 also protrudes, the upper line of electric force is generated from one point, and the lower collector Head to 10. The electric field distribution and the direction of the electric lines of force in FIG. 4 are different from those of the conventional spinneret in FIG. Depending on the electric field distribution and the direction of the electric lines of force, the core-sheath structure spinning jet draws a spiral trajectory and is attracted to the collector 10 to obtain a thin fiber, that is, a nanofiber. Moreover, since the density of the electric lines of force is concentrated in the needle part 3a and the sheath side nozzle 5a of the core side nozzle 3, it is not necessary to increase the applied voltage unnecessarily.

  In addition, when the protrusion amount of the needle portion 3a tip of the core side nozzle 3 from the tip end of the sheath side nozzle 5a was changed and the morphology of the nanofiber having the core sheath structure was examined, the following tendency was observed.

Protrusion 1 mm: Taylor cone was confirmed at the tip of the nozzle. As a result, fibers having a relatively uniform diameter were confirmed.
Protrusion amount 3 mm: The Taylor cone at the tip of the nozzle was not stable, and as a result, fibers with varying diameters were confirmed.
Similar to the result of the protrusion amount of 6 mm: 3 mm, the Taylor cone at the tip of the nozzle was not stable, and a fiber with large variation in diameter was confirmed. The bead shape was also confirmed.

  In addition to the core-sheath structure, a hollow structure nano-fiber can be manufactured by appropriately selecting the first solution and the second solution. In addition, the first solution and the second solution include a solution obtained by dissolving a first material serving as a core of a fine fiber having a core-sheath structure and a second material serving as a sheath in a solvent, and a liquid obtained by melting these materials. Can be used.

  Moreover, although the example which changed the protrusion amount of the needle part 3a tip of the core side nozzle 3 from the tip of the sheath side nozzle 5a was shown, in the spinneret of the embodiment, the tip side of the core side nozzle 3 is used as a reference position, Since the position of the tip of the nozzle 5a can be adjusted in the plus direction (sheath side nozzle protrusion) and the minus direction (core side nozzle protrusion), the adjustment range can be increased.

  Furthermore, in the present embodiment, an example in which the core part is singular and the core part and the sheath part are arranged coaxially has been shown. However, a nano-fiber having a structure in which there are a plurality of core parts and is arranged inside the sheath part. In manufacturing, the same can be applied by using one having a plurality of core side nozzles.

  In the present invention, since the spinneret of the present invention can be incorporated into an apparatus that has already been systemized as a single-fiber electrospinning apparatus, spinning of hollow or core-sheath nanofibers is facilitated for the user. Moreover, the reproducibility of the hollow or core-sheath nanofiber can be improved. Furthermore, by adjusting the protrusion amount of the sheath side nozzle, the possibility of controlling the morphology of the nanofiber, which has been impossible with conventional spinnerets, is further expanded.

  In the present invention, it is not necessary to increase the voltage to be applied, the positional relationship between the core-side nozzle and the sheath-side nozzle can be adjusted, and the nanofibers having different morphologies can be obtained by simply replacing the core-side nozzle and the sheath-side nozzle. As spinnerets for electrospinning devices that can be manufactured, biomedical fields such as regenerative medicine engineering, wound materials, drug delivery, etc., biomolecules such as affinity membranes and sensors for purifying biomolecules and purifying contaminated water Technology / environmental engineering field, polymer battery, dye-sensitized solar cell, energy field such as polymer membrane fuel cell, etc., or protective / security such as composite material reinforcement, anti-terrorism attack against bioterrorism, gas attack Can be used in a wide range of fields.

It is a partially notched front view which shows the structure of the spinneret which concerns on embodiment of this invention. It is an enlarged view of the core side nozzle in the spinneret which concerns on embodiment of this invention. 1 is an overall system configuration diagram of an embodiment of the present invention. It is explanatory drawing which shows the electric field strength at the time of using the spinneret of this Embodiment, and an electric-force line. It is explanatory drawing which shows the electric field strength and electric line of force by the conventional spinneret.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 1a Passage 2 Core side casing 2a Passage 2b Core side nozzle mounting cylinder 3 Core side nozzle 3a Needle part 3b Boss part 3c Flange part 4 Nozzle holder 5 Sheath side casing 5a Sheath side nozzle 6 Screw 7 1st liquid supply tube 8 Second liquid feeding tube 9 Connector 10 Collector 11 High voltage power supply 12 Tube connector

Claims (3)

A spinneret for an electrospinning device for producing a core-sheath fiber structure,
A core-side nozzle that discharges the first solution that becomes the core of the fiber structure of the core sheath;
A sheath side nozzle provided on the outer periphery of the core side nozzle;
A sheath side casing formed with a second solution supply path for supplying the second solution to the sheath side nozzle;
When the sheath-side casing is attached to the outer periphery of the core-side nozzle, the core-side nozzle is inserted inside the sheath-side nozzle, and the core-side nozzle protrudes a predetermined length from the tip of the sheath-side nozzle. A spinneret for an electrospinning device.   The spinneret for an electrospinning device according to claim 1, wherein the amount of protrusion of the core side nozzle from the tip of the sheath side nozzle can be changed by adjusting the mounting position of the sheath side casing. A core-side casing including a core-side nozzle mounting cylinder that detachably mounts the boss of the core-side nozzle and supplies the first solution to the core-side nozzle;
The spinneret for an electrospinning device according to claim 1, further comprising a nozzle holder that fixes an outer periphery of the core side nozzle to the core side casing.

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