Process and apparatus for producing nanofiber and polymer web

Abstract

A process and apparatus for producing nanofiber and polymer web, the electroconductive rotary vessel (1, 36) having a plurality of small holes (3) is rotated while supplying a polymer solution (11), prepared by dissolving a polymer material in a solvent, into the rotary vessel (1, 36). Electric charges are applied by electrifying means (14, 19) to the polymer solution (11) which flows from the small holes (3) in the rotary vessel (1, 36). The flowout linear polymer solution (11) is stretched by electrostatic explosion induced by centrifugal force and the evaporation of the solvent to produce nanofibers (f) formed of a polymer material. The nanofibers (f) in the course of the production thereof are allowed to flow so as to be deflected from one side to the other side in a shaft center direction of the rotary vessel (1, 36) by a reflection electron (16) and / or air blow means (34, 46, 59) and to be deposited to produce a polymer web, whereby nanofibers and a polymer web using the nanofibers can be produced with good productivity uniformly and in a simple construction.

Description

technical field [0001] The invention relates to a method and a device for manufacturing a nanofiber formed of a polymer substance and a high-porosity polymer web (polymer web) formed by stacking the nanofiber. Background technique [0002] Conventionally, an electrospinning method (charge induction spinning method) is known as a method for producing nanofibers formed of a polymer substance and having a submicron-scale diameter. In the conventional electrospinning method, by supplying a polymer solution to a needle-shaped nozzle to which a high voltage is applied, the polymer solution flowing out in a linear form from the needle-shaped nozzle is charged, and the solvent of the polymer solution Evaporation, the distance between the charged charges becomes smaller, and the Coulomb force acting becomes larger. When the Coulomb force exceeds the surface tension of the linear polymer solution, the linear polymer solution is explosively extended. By making the The phenomenon calle...

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Problems solved by technology

[0008] However, in Figure 21 and Figure 22A , Figure 22B In the structure shown, in order to produce a polymer network with higher productivity, the arrangement interval of the nozzles 81 on the spinning unit 82 and the arrangement intervals of the nozzles 81 in each multi-nozzle 81A are reduced to increase the unit area. When the number of nozzles, such as Figure 23 As shown, since the polymer substances flowing out from the nozzles 81 are charged with the same polarity, the polymer substances repel each other as shown by the arrow G, and the outflow of the polymer substances from the nozzle 81 in the center is hindered. At the same time, the outflow direction of the polymer substance from the nozzle 81 of the peripheral part will be towards the outside, so that the accumulation distribution of nanofibers on the collector electrode 86 will be extremely reduced in the central part and concentrated in the peripheral part, and there will be no way to make a uniform polymer substance. mesh problem

[0009] In addition, when the charge distribution plate 87 is arranged near the front end of the nozzle 81, as Figure 24 As shown, the electrical interference between the nozzles 81 can be reduced, and by forming the electric field E from the charge distribution plate 87 toward the collector electrode 86, the polymer material flowing out from each nozzle 81 can be accelerated toward the collector electrode 86. ,and Figure 23 Compared with time, the accumulation distribution of the nanofibers in the central part and the peripheral part can be uniformed to some extent, but on the other hand, the arrangement pattern of the nozzle 81 will be directly projected on the accumulation distribution, and there is a problem that the accumulation distribution cannot be achieved. Problems with full effect in homogenization

[0010] In addition, when the arrangement density of the nozzles 81 is increased, the fibers may come into contact with each other and be welded to each other in a state where the solvent has not evaporated sufficiently, and the concentration of the evaporated solvent in the space near the nozzles becomes high, and the insulating properties may be lowered. Problems where corona discharge occurs and fibers cannot be formed

[0011] In addition, when a large number of nozzles 81 are arranged, it is difficult to uniformly supply the liquid polymer substance to each nozzle 81, so there is a problem that the device structure becomes complicated and the equipment cost increases.

And, in order to produce the electrostatic explosion of the liquid polymer substance flowing out from the nozzles 81, it is necessary to concentrate the electric charges. Therefore, each nozzle 81 is formed into a thin and long shape, but many thin and long nozzles 81 are always maintained at an appropriate position. The maintenance required by the state is also extremely difficult, and there is such a problem

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