Patent Application
20200216981
The present invention relates to an apparatus and to a method for producing ultrafine fibers. The present invention more particularly applies to nanofiber spinning by a laser drawing method in which raw fibers are melted by laser light and the fibers are drawn by a drawing gas stream that is jetted from a nozzle.
Patent Document 1 discloses a method for producing nanofibers by laser drawing. Patent Document 2 proposes a method for producing nanofibers using vibration spinning of a multifilament. The method in Patent Document 2 improves poor productivity and uniformity which are problems in the technique of Patent Document 1. In Patent Document 2, the multifilament is fed into a nozzle and vibrated so that, from the viewpoint of forming a plurality of nanofibers, the nanofibers can be produced with high productivity. Additionally, since a large number of nanofibers is generated from one orifice and are blown at random by vibration, a highly uniform nonwoven fabric can be obtained with a reduced number of orifices.
It is important in the technique of Patent Document 2 to control a vibration angle of the multifilament, and if the vibration angle is significantly large, melted raw yarns and drawn fibers may come into contact with a nozzle surface. When the melted raw yarns come into contact with an orifice surface, and when the drawn fibers fly around a drawing gas stream and the drawn fibers and the like adhere to the surroundings of the nozzle to contaminate the nozzle, a stable operation for a long time may not be possible. Additionally, when the vibrational state of the multifilament is unstable, melted lumps (resin masses called “shot beads”) of the raw yarn resin may be generated. The melted lumps may adhere to a product and deteriorate its quality.
The present invention has been made in view of the circumstances described above. An object of the present invention is to provide an apparatus for producing ultrafine fibers and a method therefor capable of producing the ultrafine fibers stably for an extended time and reducing the amount of resin mass generated due to poor drawing.
Another object of the present invention is to provide a producing apparatus and a producing method by which ultrafine fibers can be produced stably for an extended time with higher productivity and the quality of a product can be improved by preventing the drawn ultrafine fibers from adhering to the nozzle portion.
According to one aspect of the present invention, there is provided an apparatus for producing ultrafine fibers which includes a nozzle portion having an inlet for feeding a raw fiber, a first jet outlet which communicates with the inlet and which jets a first drawing gas stream for delivering and drawing the raw fiber, and a second jet outlet which is arranged in a periphery of the first jet outlet and which jets a second drawing gas stream; a laser irradiation unit which is installed on the nozzle portion to irradiate laser light to the raw fiber delivered from first jet outlet and melt the raw fiber; and a drawing chamber for drawing the melted raw fiber by using the first drawing gas stream and the second drawing gas stream which are jetted from the nozzle portion.
Additionally, in the apparatus for producing ultrafine fibers, the second drawing gas stream has a slower flow speed than the first drawing gas stream.
Furthermore, the first and the second drawing gas streams are generated by a pressure difference between inside and outside of the drawing chamber.
Furthermore, the apparatus for producing ultrafine fibers of the present invention further includes a speed adjustment mechanism for controlling a flow speed of the second drawing gas stream.
The speed adjustment mechanism includes a valve or a regulator.
Furthermore, the apparatus for producing ultrafine fibers of the present invention further includes a speed controller for adjusting an amount of air flowing to the second jet outlet, wherein the speed controller is operated to control the flow speed of the second drawing gas stream.
The apparatus for producing ultrafine fibers of the present invention further includes a sensor for detecting the flow speed or a flow rate of the second drawing gas stream, a speed controller for adjusting an amount of air flowing to the second jet outlet, and a control device for controlling the speed controller based on the flow speed or the flow rate of the second drawing gas stream detected by the sensor and controlling the flow speed of the second drawing gas stream.
Furthermore, the second jet outlet is provided concentrically on the periphery of the circular first jet outlet, and the second drawing gas stream is generated to surround a periphery of the first drawing gas stream.
Furthermore, the second jet outlet is holes of a porous metal member installed in the periphery of the first jet outlet.
Furthermore, the nozzle portion includes a plurality of the inlets and the first jet outlets, and the second jet outlets are provided in the peripheries of the first jet outlets, respectively.
Still further, according to another aspect of the present invention, there is provided a method for producing ultrafine fibers, which includes feeding a raw fiber to an inlet of a nozzle portion and delivering the raw fibers from a first jet outlet which communicates with the inlet to a drawing chamber; irradiating the raw fiber delivered to the drawing chamber with laser light to melt the raw fiber; and drawing the melted raw fiber by using a first drawing gas stream for drawing the raw fiber which is jetted from the first jet outlet and a second drawing gas stream which is jetted from a second jet outlet arranged in a periphery of the first jet outlet.
According to the above-configured apparatus and method for producing ultrafine fibers, the melted fibers are drawn by means of the first drawing gas stream and the second drawing gas stream in the periphery of the first drawing gas stream, so that droplets which cause contamination and are generated when the fibers are drawn by the first drawing gas stream are blown by the second drawing gas stream and can be suppressed from adhering to the periphery of the first jet outlet of the nozzle. Moreover, the second drawing gas stream is generated in the periphery of the first drawing gas stream, so that the vibration range of the fibers protruding from the first jet outlet where the first jet outlet serves as the starting point is restricted, and shaking of the fibers is suppressed. Thus, the amount of resin mass generated can be reduced. Therefore, it is possible to provide the apparatus for producing ultrafine fibers and a method thereof capable of producing the ultrafine fibers stably for a long time and reducing the amount of resin mass generated due to poor drawing.
Additionally, the droplets which cause contaminants can be suppressed from adhering to the periphery of the first jet outlet of the nozzle, and thus, less cleaning of the nozzle portion and the extended continuous operation time of the producing apparatus are possible. Furthermore, since the amount of resin mass generated can be reduced, the resin mass adhered to the product can be reduced, and the quality of the product can be improved. As a result, it is possible to provide the producing apparatus and the producing method that can produce ultrafine fibers stably for a long time with higher productivity, and can improve the quality of the product.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The present invention relates to a method and an apparatus for producing ultrafine fibers having a fiber diameter (diameter) of 10 nm to 1 μm, preferably 30 nm to 800 nm.
More specifically, the raw fiber 25 is made of a thermoplastic resin capable of being processed into a yarn. Examples of such thermoplastic resin include: polyester resins such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, polyglycolic acid, and polyarylate, polyamide resins such as nylons (nylon 6, nylon 12, and nylon 66) and aromatic polyamides, polyolefin resins such as polypropylene and polyethylene, polyvinyl alcohol polymers such as ethylene-vinyl alcohol copolymers and ethylene-vinyl acetate copolymers, polyacrylonitrile polymers, fluorinated polymers such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers (PFAs), ethylene-tetrafluoroethylene copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, and polyvinylidene fluoride, polyurethane polymers, polyvinyl chloride polymers such as polyvinyl chloride and polyvinylidene chloride, polystyrene polymers such as polystyrene and syndiotactic polystyrene, poly(meth)acrylic polymers such as polymethacrylate methyl, polyoxymethylene, ether-ester polymers, cellulose polymers such as cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate, polyurethane resins, polyacetal resins, polycarbonate resins, modified polyphenylene ether resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyetherketone resins, polyimide resins, polyetherimide resins, and engineering plastics such as liquid crystal polymers (LCPs). Examples of the thermoplastic resins for the raw filaments may further include any combination of the above polymers and/or may optionally contain one or more additives such as a plasticizer, a surfactant and an antioxidant. Among the above, polyethylene terephthalate, polylactic acid, nylons (nylon 6 and nylon 66), and polypropylene are especially suitable for use in production of ultrafine fibers due to their good drawing and molecular orientation properties. Examples of the thermoplastic resins for the raw filaments may further include any combination of the above polymers and/or may optionally contain one or more additives such as a plasticizer, a surfactant and an antioxidant. Among the above, polyethylene terephthalate, polylactic acid, nylons (nylon 6 and nylon 66), and polypropylene are especially suitable for use in production of ultrafine fibers due to their good drawing and molecular orientation properties.
Additionally, when the raw fiber 25 is multifilament, the multifilament of a bundle of at least 10 monofilaments (filaments) is used. The number of monofilaments to be bundled is appropriately adjusted depending on the ratio of the size of the jet outlet of the nozzle 10 to be used and the total cross-sectional area of the multifilament. For example, the multifilament constituted by at least 10 monofilaments, preferably at least 20 monofilaments, and more preferably, at least 40 monofilaments, is used. The diameters of filaments constituting the multifilament range from 10 to 200 μm. The multifilament is twisted so that a plurality of filaments does not lose integrity as a bundle or does not fall apart. The number of twists is, for example, at least 20 times/m) but is appropriately adjusted depending on the number, shape, material, or the like, of multifilaments.
A laser irradiation unit 26 on which the nozzle 10 is installed is installed on top of the drawing chamber 21. When the drawing chamber 21 is depressurized by the vacuum pump (not illustrated), the air flows from the nozzle 10 into the drawing chamber 21 due to the pressure difference between the inside and the outside of the drawing chamber 21 to generate a first drawing gas stream 16. A second drawing gas stream 17 having a slower flow speed than the first drawing gas stream 16 is generated in the periphery of the first drawing gas stream 16.
In this state, the laser is irradiated from the carbon dioxide gas laser oscillator 27 through the irradiation window 28 to the raw fiber 25 protruding from the jet outlet of the nozzle 10 to partially dissolve the raw fiber 25, and the melted fiber is drawn by the first drawing gas stream 16 and the second drawing gas stream 17 to produce nanofibers (ultrafine fibers) 40.
At this time, if the flow speed of the second drawing gas stream 17 is too fast, the vibration of raw yarn may be destabilized, and if the flow speed is too slow, the effect is weakened. Thus, it is preferable that the pressure in the drawing chamber 21 be adjusted, and the flow rate be adjusted by installing a valve in the passage that generates the second drawing gas stream 17.
Additionally, the fiber diameter of the nanofibers 40 can be controlled relatively easily by changing the drawing conditions such as the feeding speed of the raw fiber 25, the output of the carbon dioxide gas laser oscillator 27, and the pressure difference between the inlet side and the jet outlet side of the nozzle 10.
In
A second passage 18 that generates the second drawing gas stream 17 having a slower flow speed than the first drawing gas stream 16 is formed in the boundary region between the outer nozzle portion 11 and the inner nozzle portion 12. A second jet outlet 19 is provided concentrically on the periphery of the circular first jet outlet 15 of the inner nozzle portion 12, and the second jet outlet 19 jets the second drawing gas stream 17 that flows through the second passage 18. In this example, an extended portion 18a in which a part of the second passage 18 is expanded is formed. The extended portion 18a works as the chamber that suppresses the change of flow speed of the second drawing gas stream 17 that is generated by the air (indicated by an arrow A2) drawn from the second inlet 20.
The factors that determine the flow speed of the first drawing gas stream 16 of the inner nozzle are the pressure difference between the side of the first inlet 14 and second inlet 20 and the side of the first jet outlet 15 and second jet outlet 19, and the area ratio of the first inlet 14 to the first jet outlet 15. On the other hand, the factors that determine the flow rate of the second drawing gas stream of the outer nozzle are the pressure difference between the side of the first inlet 14 and second inlet 20 and the side of the first jet outlet 15 and second jet outlet 19, and the area ratio of the portion with the smallest cross-sectional area in the second passage 18 to the second jet outlet 19. Furthermore, the speed ratio of the first drawing gas stream 16 to the second drawing gas stream 17 is important when securing the stability of spinning and obtaining the contaminants inhibition effect of the double nozzle. According to the experiment, the desired range of the flow speed ratio of the first drawing gas stream 16 to the second drawing gas stream 17 (second drawing gas stream 17/first drawing gas stream 16) is 1.0 to 0.1.
For example, as illustrated in the enlarged views in
Furthermore, the first jet outlet 15 is located in the inside of the second jet outlet 19 by T which ranges from 0 mm to 1.0 mm, for example, by 0.2 mm, so that the first jet outlet 15 can be suppressed from being damaged during the cleaning of the tip portion of the nozzle 10. If T is 0 to 0.5 mm, the level of adverse effect on spinning is negligible. When offset over 1.0 mm is applied, the larger the amount of offset becomes, the more unstable the vibration spinning state is. Note that La ranges from 0.1 mm to 10 mm, and Lc ranges from 0.1 mm to Φc. If La/Φa becomes too large, yarn clogging is likely to occur. Lc is of a length that does not occlude the second passage 18. By taking them into consideration, a preferable example is expressed by, La=3×Φa, and Lc=0.9×Φc.
In this case, the pressure P1 in the drawing chamber 21 and the pressure P2 in the raw fiber feeding chamber are expressed by P1>P2, preferably P1≥2P2, more preferably P1≥3P2, and most preferably P1≥5P2. The pressure difference between P1 and P2 (P1−P2) is specifically preferably 20 kPa or more, more preferably 50 kPa or more, and most preferably 70 kPa or more. By having such a pressure ratio, the first drawing gas stream 16 becomes a subsonic to supersonic speed region.
The raw fiber fed from the first inlet 14 of the nozzle 10 is guided to the first jet outlet 15, and while the second drawing gas stream 17 is jetted from the second jet outlet 19 to the surroundings of the first drawing gas stream 16, the laser is irradiated to the raw fiber protruding from the first jet outlet 15 to partially dissolve the raw fiber, and the melted fiber is drawn by the first drawing gas stream 16 and the second drawing gas stream 17 to produce the ultrafine fibers.
Although the raw fiber fed from the first inlet 14 can be monofilament, using the multifilament raw yarn generates a large number of nanofibers from one nozzle 10 so that the productivity can be improved. The “multifilament” is a bundle of monofilaments. No particular limitation is imposed on the cross-sectional shape of the monofilaments constituting the multifilament, and various modified cross-section raw yarns such as circular, ellipsoidal, tetragonal, trigonal, trapezoidal, or polygonal cross-sections may be used. Hollow yarns and composite raw yarns such as sheath-core raw yarns and side-by-side raw yarns may also be used. Furthermore, the raw yarns constituting the multifilament may be different from each other. The multifilament may consist of monofilaments having different cross-sectional shapes and/or different materials.
By using the nozzle 10 having the above-described configuration, while the second drawing gas stream 17 is generated from the second jet outlet 19 to the surroundings of the first drawing gas stream 16, the laser is irradiated to partially dissolve the raw fiber 25. Consequently, the droplets which cause contaminants and are generated when the fiber is drawn by the first drawing gas stream 16 are blown downward by the second drawing gas stream 17, and the droplets can be suppressed from adhering to the surroundings of the first jet outlet 15 of the nozzle 10. Furthermore, the second drawing gas stream 17 is generated from the second jet outlet 19 to the surroundings of the first drawing gas stream 16, so that the vibration range of the fibers (vibrators) protruding downward from the first jet outlet 15 where the first jet outlet 15 serves as the starting point is restricted, and shaking of the fibers can be suppressed. Thus, the amount of resin mass generated due to poor drawing can be reduced.
The above-described producing apparatus and method require less cleaning of the nozzle 10, and thus, the continuous operation time of the producing apparatus can be extended. Additionally, the resin mass is suppressed from adhering to the product (for example, nanofibers 40 or nanofiber nonwoven fabric) so that the quality can be improved. Therefore, the spinning technology can be further developed.
It is effective in this configuration to appropriately select the air permeability of the porous metal and maintain the flow speed of the second drawing gas stream 17 in an appropriate range. In this case as well, the desired range of the flow speed ratio of the first drawing gas stream 16 to the second drawing gas stream 17 (second drawing gas stream 17/first drawing gas stream 16) is 1.0 to 0.1.
Since other configurations are the same as those in
Such configured nozzle 10 can also obtain substantially the same operational effects as those of the first configuration example. Additionally, the second configuration example of the nozzle 10 can be similarly applied as the nozzle 10 of the apparatus for producing ultrafine fibers as illustrated in
Since other configurations are the same as those in
Such a configured nozzle 10 can also obtain substantially the same operational effects as those of the first and second configuration examples. Additionally, the third configuration example of the nozzle 10 can be similarly applied as the nozzle 10 of the apparatus for producing ultrafine fibers as illustrated in
That is, a hollow-annular-shaped speed adjustment chamber 53 is provided to cover the second inlet 20 of the nozzle 10, and the air is supplied from the speed controller 50 to the speed adjustment chamber 53 through the pipe 54. Under the control of the flow rate control device 51, and based on the air amount or the flow speed detected by the air flow sensor 52, the speed controller 50 supplies the air to the speed adjustment chamber 53 while adjusting the amount of air (an arrow A3) introduced so that the flow speed of the second drawing gas stream 17 becomes a predetermined value. The air introduced into the speed adjustment chamber 53 is supplied to the second inlet 20 of the nozzle 10. Then, the raw fiber fed from the first inlet 14 of the nozzle 10 is guided to the first jet outlet 15, and the second drawing gas stream 17 whose flow speed is controlled is jetted from the second jet outlet 19 to the surroundings of the first drawing gas stream 16. In this state, the laser is irradiated to the raw fiber protruding from the first jet nozzle 15 to partially dissolve the raw fiber, and the melted fiber is drawn by the first drawing gas stream 16 and the second drawing gas stream 17 to produce the ultrafine fibers.
In this way, by performing feedback control on the flow speed of the second drawing gas stream 17, the flow speed of the second drawing gas stream can be controlled more precisely, and the amount of resin mass generated due to poor drawing can be further reduced.
In the second embodiment, the flow speed of the second drawing gas stream 17 is controlled by performing feedback control. However, instead of providing the flow rate control device 51 or the flow rate sensor 52, for example, the speed controller with the scale may be provided so that the operator can control the flow rate by manual operation while visually checking the scale.
The laser irradiation unit 37 on which the multiple nozzles 100 are installed is installed on top of the drawing chamber 33. When the drawing chamber 33 is depressurized by the vacuum pump (not illustrated), the pressure difference between the inside and outside of the drawing chamber 33 causes the air to flow from each nozzle portion into the drawing chamber 33 to generate the first drawing gas stream from the first jet outlet portion. Additionally, the second drawing gas stream which has a slower flow speed than the first drawing gas stream is generated from the second jet outlet portion to the surroundings of the first drawing gas stream.
In this state, the laser is irradiated from the carbon dioxide gas laser oscillator 38 through the irradiation window along the arrangement direction of the nozzle portion to the raw fibers 35 which protrude from the first jet outlet portion of each nozzle portion to partially dissolve the raw fibers 35, and the melted fibers are drawn by the first and second drawing gas streams to simultaneously turn the n fibers into nanofibers. The formed nanofibers are turned into a sheet on the net conveyor 39 to produce the nanofiber nonwoven fabric 41.
Here, as is the case with the first embodiment, the fiber diameter of the nanofibers can be controlled relatively easily by changing the drawing conditions such as the feeding speed of the raw fibers 35, the output of the laser oscillator 38, and the pressure difference between the inlet side and the jet outlet side of the multiple nozzles 100.
Providing the laser irradiation unit 37 protruding from the drawing chamber 33 is not necessarily required, if the laser is irradiated from the window of the drawing chamber 33.
Second passages 18-1, 18-2, . . . , 18-n are formed on the other surface of the plate-shaped member 110. The second jet outlets 19-1, 19-2, . . . , 19-n are provided concentrically on the peripheries of the first jet outlets 15-1, 15-2, . . . , 15-n. In this example, the extended portion 18a is formed in the second passages 18-1, 18-2, . . . , 18-n to function as the chamber for suppressing the change of flow speed.
Due to the pressure difference between the side of the first inlet portions 14-1, 14-2, . . . , 14-n and the side of the first jet outlet portions 15-1, 15-2, . . . , 15-n, the first drawing gas streams 16-1, 16-2, . . . , 16-n for drawing the melted fibers are generated from the first jet outlet portions 15-1, 15-2, . . . , 15-n respectively, and the second drawing gas streams 17-1, 17-2, . . . , 17-n are generated from the second jet outlet portions 19-1, 19-2, . . . , 19-n.
The individual nozzle portions 10-1, 10-2, . . . , 10-n basically have the same configurations as the nozzle illustrated in
In such configured multiple nozzles 100, as is the case with the first to third configuration examples, while the second drawing gas streams 17-1, 17-2, . . . , 17-n are generated from the second jet outlet portions 19-1, 19-2, . . . , 19-n to the surroundings of the first drawing gas streams 16-1, 16-2, . . . , 16-n, the laser is irradiated to partially dissolve the raw fibers 35. Consequently, the droplets which cause contaminants and are generated when the fibers are drawn by the first drawing gas streams 16-1, 16-2, . . . , 16-n are blown downward by the second drawing gas streams 17-1, 17-2, . . . , 17-n, and the droplets can be suppressed from adhering to the surroundings of the first jet outlet portions 15-1, 15-2, . . . , 15-n of the nozzle portions 10-1, 10-2, . . . , 10-n. Furthermore, the second drawing gas streams 17-1, 17-2, . . . , 17-n are generated from the second jet outlet portions 19-1, 19-2, . . . , 19-n to the surroundings of the first drawing gas streams 16-1, 16-2, . . . , 16-n so that the vibration ranges of the fibers (vibrators) protruding downward from the first jet outlet portions 15-1, 15-2, . . . , 15-n where the first jet outlet portions 15-1, 15-2, . . . , 15-n serve as the starting point are restricted, and shaking of fibers can be suppressed. Thus, the amount of resin mass generated due to poor drawing can be reduced.
Therefore, the above-described producing apparatus and method require less cleaning of the nozzle portions 10-1, 10-2, . . . , 10-n, and thus, the continuous operation time of the producing apparatus can be extended. Additionally, the resin mass is suppressed from adhering to the product (for example, the nanofiber nonwoven fabric 41) so that the quality can be improved. Moreover, since a large number of nanofibers can be formed from the n nozzle portions 10-1, 10-2, . . . , 10-n respectively, the spinning technology can be further developed, and the nanofiber nonwoven fabric 41 can be efficiently produced.
The conveyor collecting type multi-drawing device which has been described as the example in the fourth configuration example can also be applied to the reel winding type multi-drawing device. The fourth configuration example is also applicable to the continuous winding type multi-drawing device that performs continuous winding by transferring the nanofiber nonwoven fabric collected on the net conveyor to the interlayer paper such as the PET film.
Also, in the fourth configuration example, as is the case with the second and third configuration examples, the porous metal member 31 can be installed in the peripheries of the first jet outlet portions 15-1, 15-2, . . . , 15-n, or the speed adjustment mechanism 32 for controlling the flow speed of the second drawing gas streams 17-1, 17-2, . . . , 17-n may be provided in the surroundings of the second inlet.
Furthermore, as is the case with the second embodiment, the speed controller 50 may be provided to perform feedback control on the flow speed of the second drawing gas stream 17. It is of course possible to provide the speed controller with the scale as in the First Modification to perform flow rate control by manual operation.
The inventors of the present invention used the conventional nozzle and the nozzle of the present invention to measure and examine the contaminants near the nozzle jet outlet.
It can be seen from this measurement result that the contaminants caused by the adhesion of droplets can be reduced to 1/100 or less to the conventional nozzle.
However, the amount of contaminants was too small to be measured in the 10-minute operation in the present invention. Thus, the value which was measured after the 30-minute operation was converted to the 10-minute operation.
Although the present invention has been described using the first to third embodiments, the first modification, and the first to fourth nozzle configuration examples, the present invention is not limited thereto. Various modifications are possible without departing from the scope of the invention in the operational phase.
For example, the pressure in the drawing chamber 21 is reduced and feeding of the raw fiber 25 is performed at atmospheric pressure. Instead, the raw fiber feeding chamber may be provided and pressurized to perform drawing at atmospheric pressure. Furthermore, it is clear that the pressure difference can be generated by providing the drawing chamber and the raw fiber feeding chamber. In this case, the relationship expressed by “P2>P1” is satisfied, where P1 is the pressure in the drawing chamber and P2 is the pressure in the feeding chamber of the raw fiber. Additionally, the raw fiber 25 can be fed from the first inlet 14 at atmospheric pressure, and the air can be supplied to the extended portion (chamber) 18a via the pump or the like. The air pressure P3 in this case is, for example, expressed by “P3>P1” and “P3<P2”.
Additionally, a plurality of slit-like second jet outlets may be provided at the tip portion of the nozzle portion 10 so as to surround the periphery of the first jet outlet 15, and to jet the second drawing gas stream 17 having a slower flow speed than the first drawing gas stream. Various configurations other than the double nozzle structure can be applied, if the second drawing gas stream 17 having a slower flow speed than the first drawing gas stream 16 can be jetted to the periphery of the first drawing gas stream 16 at the time of drawing the melted fiber in the drawing gas stream.
Furthermore, the above embodiments include inventions at various stages, and various inventions may be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some of all constituent elements indicated in the embodiments are deleted, as long as at least one of the problems described in the Problem to be solved by the invention can be solved and at least one of the effects described in the effects of the invention can be obtained, such configuration from which the constituent elements are deleted may be extracted as the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-126325 | Jun 2017 | JP | national |
The present application is a national stage entry under 35 USC § 371 of International Application No. PCT/JP2018/024577, filed on Jun. 28, 2018, which claims priority to Japanese Patent Application No. 2017-126325 filed on Jun. 28, 2017, the disclosures of which are herein incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/024577 | 6/28/2018 | WO | 00 |
