JP2007303031A - Nozzle for electrospinning and method for producing fine thermoplastic resin fiber using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle for electrospinning, which provides a fine thermoplastic resin fiber having a uniform diameter by a solution electrospinning method and to provide a method for producing a fine thermoplastic resin fiber using the same. <P>SOLUTION: The nozzle for electrospinning has a constitution that a groove-shaped storage tank of a solution of a thermoplastic resin in a solvent and a lip part reaching from one end part of the storage tank of a solution of a thermoplastic resin in a solvent to one end of a conductive block body are formed on the surface of the conductive block body and the lip part is equipped with a plurality of fine flow channels which reaches from the storage tank of a solution of a thermoplastic resin in a solvent to the one end part of the conductive block body and overflows the solution of the thermoplastic resin in the solvent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrospinning nozzle and a method for producing fine thermoplastic resin fibers by solution electrospinning using the nozzle.

  In general, fine fibers called nanofibers with a nano-order fiber diameter have a very large surface area, such as battery separators, electromagnetic shielding materials, filters, artificial leather, artificial blood vessels, cell culture substrates, IC chips, organic EL, solar cells, etc. Expected to be used for

  However, since nanofibers are very thin in the order of nanometers, they cannot be produced by a spinning method for producing ordinary fibers. Therefore, production by an electrospinning method has been actively studied recently.

As the electrospinning method, the solution electrospinning method is the most common. As shown in FIG. 4, a thermoplastic resin solvent solution obtained by dissolving a thermoplastic resin in a solvent is stored in the storage tank 10. From the nozzle 11 provided at the bottom, the thermoplastic resin solvent solution 14 is hung toward the target 12 and the nozzle 11 becomes a positive electrode, and the target 12 becomes a negative electrode. A method of applying a high voltage is known (for example, see Non-Patent Documents 1 and 2).
Processing technology Vol. 40, no. 2 (2005) 101-103 Processing technology Vol. 40, no. 3 (2005) 167-171

  In the solution electrospinning method, spraying a single thermoplastic resin solvent solution from the tip of the nozzle is low in productivity, so a large number of holes are formed at the nozzle tip and a large number of thermoplastic resin solvent solutions are sprayed. Thus, it has been studied to produce a large number of fine fibers at a time.

  However, when spraying the thermoplastic resin solvent solution from a large number of holes formed near the tip of the nozzle, the size of the sprayed thermoplastic resin solvent solution varies even if the shape and size of the holes are the same, As a result, there has been a drawback in that there is a variation in diameter of the fine thermoplastic resin fibers obtained by electrospinning.

  In view of the above problems, an object of the present invention is to provide an electrospinning nozzle capable of obtaining a fine thermoplastic resin fiber having a uniform diameter by a solution electrospinning method, and a method for producing a fine thermoplastic resin fiber using the same. Is to provide.

  The nozzle for electrospinning of the present invention has a groove-like thermoplastic resin solvent storage tank on the upper surface of the conductive block, and one end of the conductive block from one end of the thermoplastic resin solvent storage tank. A lip portion is formed, and a plurality of fine channels for overflowing the thermoplastic resin solvent solution from the thermoplastic resin solvent storage tank to one end portion of the conductive block-like body are formed in the lip portion. It is characterized by.

  The electrospinning nozzle of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing an example of an electrospinning nozzle according to the present invention, FIG. 2 is a front view, and FIG. 3 is a cross-sectional view taken along line AA in FIG.

  In the figure, 1 is a conductive block-like body having a substantially rectangular shape (length 65 mm, width 25 mm) in plan view, and a thermoplastic resin solvent solution having a semicircular shape (length 50 mm, width 12 mm, depth 6 mm) on the upper surface thereof. A storage tank 2 is formed. The conductive block-like body 1 in the front direction (lower side in FIG. 1) from the thermoplastic resin solvent storage tank 2 has a front end of the conductive block-like body 1 from the front end portion of the thermoplastic resin solvent solution storage tank 2. The lip part (length 50mm, width 6mm) 3 which reaches a part is formed horizontally.

  The lip portion 3 has a semicircular cross section (diameter: 1.0 mm) for overflowing the thermoplastic resin solvent solution from the thermoplastic resin solvent solution storage tank 2 to the front end of the conductive block-like body 1. Are formed at intervals of approximately 5 mm.

  Further, the thermoplastic resin solvent solution tank 2 is located at the approximate center of the thermoplastic resin solvent solution storage tank 2 in the conductive block-like body 1 in the rearward direction (upper side in FIG. 1) of the thermoplastic resin solvent solution storage tank 2. The supply port 5 is penetrated. In addition, the protrusion part 51 is formed in the back side wall of the electroconductive block-like body 1, and it penetrates so that the thermoplastic resin solvent solution supply port 5 formed in the electroconductive block-like body 1 may communicate, This protrusion part By connecting a pipe for supplying a thermoplastic resin solvent solution to 51, the thermoplastic resin solvent solution can be supplied to the thermoplastic resin solvent storage tank 2.

  The conductive block-like body 1 is formed of a material having excellent conductivity because a high voltage is applied so as to be a positive electrode when producing a fine thermoplastic resin fiber by a solution electrospinning method. Are preferable, and examples thereof include copper, iron, stainless steel, gold, silver, and brass.

  The shape of the thermoplastic resin solvent solution storage tank 2 is not particularly limited as long as it is groove-shaped, but the thermoplastic resin solvent solution can be stored and the thermoplastic resin solvent solution can be passed through each of the fine channels 4, 4. It is preferable that the lip portion 3 can be hung downward from the tip of the lip portion 3 at the same speed, so that a hook shape is preferable, and the front end portion of the lip portion 3 and the front end portion of the lip portion 3 are preferably substantially parallel.

  The fine flow path 4 is a flow path for overflowing the thermoplastic resin solvent solution overflowing from the thermoplastic resin solvent storage tank 2 from the front end portion of the lip portion 3, and applying a high voltage to the overflowing thermoplastic resin solvent solution. Since the fine thermoplastic resin fibers are produced by applying the solution electrospinning method, the amount of the thermoplastic resin solvent solution overflowing from each fine flow path is the same in order to obtain fine thermoplastic resin fibers having a uniform thickness. preferable.

  Therefore, it is preferable that the length, the cross-sectional shape, and the cross-sectional area of each of the fine channels 4, 4,. The cross-sectional shape of the microchannel 4 is not particularly limited, and examples thereof include a semicircular shape, an oval shape, a triangular shape, a quadrangular shape, a pentagonal shape, and a hexagonal shape, and a semicircular shape is preferable.

  Further, if the width of the fine flow path 4 is narrowed, the drooping thermoplastic resin solvent solution becomes thin and electrospinning cannot be performed, or the productivity decreases, and conversely when the width becomes wide, the thermoplastic resin solvent solution becomes thick and obtained. Since the diameter of a thermoplastic resin fiber becomes thick, 0.2-2.0 mm is preferable. The length of the fine channel 4 (the width of the lip portion 3) is not particularly limited. However, if the length becomes longer, the solvent evaporates and it becomes difficult to uniformly overflow the thermoplastic resin solvent solution. 3 to 10 mm.

  The thermoplastic resin solvent solution supply port 5 only needs to be formed at a position where the thermoplastic resin solvent solution can be supplied to the thermoplastic resin solvent solution storage tank 2, but even if it is a high viscosity thermoplastic resin solvent solution, The other end of the thermoplastic resin solvent storage tank 2 (opposite the lip part 3) is communicated with the approximate center so that the thermoplastic resin solvent storage tank 2 can be supplied with a uniform height to the thermoplastic resin solvent storage tank 2. It is preferable.

  The manufacturing method of the fine thermoplastic resin fiber of this invention supplies a thermoplastic resin solvent solution to the thermoplastic resin solvent solution storage tank of the electrospinning nozzle of any one of Claims 1-4, Overflow of the thermoplastic resin solvent solution from the path, and applying a high voltage so that the electrospinning nozzle becomes a positive electrode and the target installed below the electrospinning nozzle becomes a negative electrode. And electrospinning.

  The thermoplastic resin used in the present invention is not particularly limited as long as it is a thermoplastic resin that can be dissolved in a solvent. For example, high-density polyethylene resin, medium-density polyethylene resin, low-density polyethylene resin, linear low-density polyethylene resin , Polypropylene resin, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-pentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-acetic acid Olefin resins such as vinyl copolymers, ethylene- (meth) acrylic acid ester copolymers, ethylene-vinyl chloride copolymers, ethylene-propylene-butene copolymers; polyvinyl alcohol, polyethylene oxide, polylactic acid, polychlorinated Vinyl resin, polyvinylidene resin, polyvinylidene fluoride resin, polystyrene Down resins, polyacrylonitrile resins, polyacrylic resins, polyester resins, polyamide resins, polyimide resins, polycarbonate resins, polybutadiene and the like, olefin resins are preferred, more preferably a polypropylene resin.

  The solvent used in the present invention is not particularly limited as long as it is a solvent that can dissolve the thermoplastic resin, and examples thereof include water, methanol, ethanol, isopropanol, dimethylsulfamide, tetrahydrofuran, acetone, ethyl acetate, and N-vinyl. Examples include pyrrolidone, chloroform, formic acid and the like.

  The concentration of the thermoplastic resin solvent solution is not particularly limited. However, if the thermoplastic resin is not completely dissolved in the solvent, it becomes difficult to obtain fine thermoplastic resin fibers by electrospinning. , Preferably 3 to 10% by weight. Further, when the viscosity of the thermoplastic resin solvent solution is high, it becomes difficult to uniformly overflow the thermoplastic resin solvent solution from the fine flow path. Therefore, the viscosity is preferably 10 to 1000 cps, more preferably 50 to 500 cps.

  The target used in the present invention is a negative electrode when a high voltage is applied, and the manufactured fine fibers are deposited on the surface thereof. Therefore, a conductive plate-like body is preferable, for example, a copper plate , Iron plate, stainless steel plate, gold plate, silver plate, brass plate, aluminum plate, laminated plates of these conductive plates and aluminum foil, and the like. In order to obtain fine fibers continuously, the conductive plate may be belted and rotated by a roll.

  The target is placed below the electrospinning nozzle, but if the distance between the target and the electrospinning nozzle is too close, a discharge will occur and charge can be applied to the thermoplastic resin solvent solution suspended from the microchannel 4. If the distance is too far and the thermoplastic resin fibers that have been made finer do not adhere to the target, 5 to 15 cm is preferable.

  In the present invention, the thermoplastic resin solvent solution is supplied from the thermoplastic resin solvent solution supply port 5 to the thermoplastic resin solvent solution storage tank 2 so as to be higher than the bottom of the fine channel 4 and to maintain the same height. Supply solvent solution. If it does so, the thermoplastic resin solvent solution will overflow uniformly from the front-end | tip part of the fine flow path 4 (lip | rip part 3) through the fine flow path 4. FIG.

  At this time, by applying a high voltage so that the electrospinning nozzle becomes a positive electrode and the target installed below the electrospinning nozzle becomes a negative electrode, the overflowed thermoplastic resin solvent solution When a positive high voltage is applied, the thermoplastic resin solvent solution is electrospun and becomes fine fibers in the process of being sprayed on the negatively charged target surface.

  When the applied voltage is low, the thermoplastic resin solvent solution does not become fine fibers, and when it is too high, discharge between the nozzle and the target and the thermoplastic resin solvent solution does not become fine fibers, so 5 to 100 kV is preferable, more preferably. 10 to 50 kV.

  The configuration of the electrospinning nozzle of the present invention is as described above, and the thermoplastic resin solvent solution overflows from a plurality of fine channels by its own weight. Therefore, the thermoplastic resin solvent overflowed from each fine channel The amount of the solution is the same, and fine fibers having a uniform thickness can be easily produced with high productivity.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

The electrospinning nozzle shown in FIGS. 1 to 3 was used. A target made of a stainless steel plate was placed 10 cm below the electrospinning nozzle. Thermoplastic xylene solution (concentration: 8 wt%, viscosity: 100 cps / viscosity) at 80 ° C. from the thermoplastic resin solvent solution supply port 5 to the thermoplastic resin solvent solution reservoir 2 of the electrospinning nozzle. 80 ° C.) was supplied at a speed of 0.01 cm ³ / min so that the height of the solution was the height of the lip 3.

  After the hot xylene solution of polypropylene starts to overflow from the fine flow path 4, a high voltage generator applies a voltage of 13 kV so that the electrospinning nozzle is positive and the target is negative, and fine polypropylene fibers are formed on the target surface. Obtained. When the obtained fine polypropylene fiber was observed with an electron microscope, the thickness was 100 nm to 10 μm, and the length was 3 cm or more.

It is a top view which shows an example of the nozzle for electrospinning of this invention. It is a front view which shows an example of the nozzle for electrospinning of this invention. It is AA sectional drawing in FIG. It is a schematic diagram which shows an example of the conventional solution electrospinning method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive block-like body 2 Thermoplastic resin solvent solution storage tank 3 Lip part 4 Fine flow path 5 Thermoplastic resin solvent solution supply port

Claims (7)

  On the upper surface of the conductive block-like body, a groove-shaped thermoplastic resin solvent storage tank, and a lip portion from one end of the thermoplastic resin solvent solution storage tank to one end of the conductive block-like body are formed, An electrospinning characterized in that a plurality of fine channels for overflowing a thermoplastic resin solvent solution are formed in the lip portion from the thermoplastic resin solvent solution storage tank to one end of the conductive block-like body. Nozzle.   2. The electrospinning nozzle according to claim 1, wherein the plurality of fine flow paths have substantially the same length, cross-sectional shape, and cross-sectional area.   The electrospinning nozzle according to claim 1 or 2, wherein the cross-sectional shape of the fine channel is semicircular and the diameter thereof is 0.2 to 2.0 mm.   The nozzle for electrospinning according to any one of claims 1 to 3, wherein a thermoplastic resin solvent solution supply port is communicated with substantially the other end of the thermoplastic resin solvent storage tank.   A thermoplastic resin solvent solution is supplied to the thermoplastic resin solvent solution storage tank of the electrospinning nozzle according to any one of claims 1 to 4, and the thermoplastic resin solvent solution is allowed to overflow from the fine channel, A fine thermoplastic resin characterized in that electrospinning is performed by applying a high voltage so that the electrospinning nozzle becomes a positive electrode and the target installed below the electrospinning nozzle becomes a negative electrode. A method for producing fibers.   6. The method for producing fine thermoplastic resin fibers according to claim 5, wherein the applied voltage is 5 to 100 kV.   The method for producing fine thermoplastic resin fibers according to claim 5 or 6, wherein the viscosity of the thermoplastic resin solvent solution is 10 to 1000 cps.

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