Method for manufacturing fibers and apparatus for manufacturing fibers

Abstract

The present invention provides a method and apparatus for manufacturing fibers that can efficiently produce ultrafine fibers of multiple diameters using a single die. [Solution] The present invention provides a method for manufacturing fibers, in which a fibrous polymer extruded from a nozzle having multiple extrusion holes is stretched while orbiting around a straight line extending from the extrusion holes in the polymer extrusion direction, and a difference in the orbital speed of the fibrous polymer extruded from each of the extrusion holes is created. Alternatively, the present invention provides a method for manufacturing fibers, in which a torsional force is applied to the fibrous polymer extruded from the extrusion holes, causing it to rotate around a straight line extending from the extrusion holes in the polymer extrusion direction, thereby stretching it while rotating, and a difference in the rotational speed of the fibrous polymer extruded from each of the extrusion holes is created.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus suitable for manufacturing fibers.

Background Art

[0002] In recent years, high functionality of fibers has been demanded in many fields, and it is known that the performance of fibers changes depending on the diameter. Therefore, stretching is important for controlling the fiber diameter, and various studies and developments have been made on methods of extruding a thermoplastic polymer from a spinneret into a fibrous shape and stretching it, and these methods have been implemented using several stretching apparatuses. As a general stretching method, there are a method of generating a speed difference in the fiber by rotating a roller while the roller is in contact with the fiber after extrusion, and a method of applying tension to the fiber by ejecting a high-speed air flow onto the traveling fiber and generating frictional force between the fiber and the air flow. Further, by mixing fibers of different diameters in a fiber bundle formed by bundling a plurality of fibers, the properties of the fiber bundle can be changed.

[0003] Patent Document 1 discloses a method of stretching while applying a rotational force to a polymer immediately after extrusion from a die. In this fiber stretching method, torsional force and centrifugal force act on the stretching portion of the fiber, increasing the stretching force applied to the fiber, so that the fiber can be made thinner.

[0004] As a method of stretching a fiber with a high-speed air flow, Patent Document 2 discloses a method of ejecting hot air from an inclined flow path to a parallel flow path, rectifying the hot air in the parallel flow path in a direction parallel to the flow of the molten resin, and blowing the rectified hot air onto the molten resin. In this fiber manufacturing method, since the fiber is stretched while suppressing the fiber from being disturbed by the hot air, a fiber with a stable and small diameter can be manufactured.

Prior Art Documents

Patent Documents

[0006] Patent Document 1 discloses a configuration in which a rotational force is applied to the extruded fibers by rollers or a swirling flow to rotate the yarn, but it does not disclose how to spin fibers of different diameters for each extrusion hole when spinning with two or more extrusion holes.

[0007] The fiber manufacturing method described in Patent Document 2 involves forming a straightened airflow by converging hot air beforehand, and then blowing the airflow parallel to the extruded polymer. The fiber is stretched solely by the frictional force acting between the polymer and the airflow. Therefore, there are limitations to the hot air supply conditions that allow for stable spinning, and the range of obtainable fiber diameters is limited. To significantly change the fiber diameter, it is necessary to change the polymer extrusion rate. Consequently, when spinning with two or more extrusion holes, in order to spin fibers of different diameters from each extrusion hole, it is necessary to manufacture a die that adjusts the pressure drop of the extrusion hole according to the fiber diameter, which increases the manufacturing cost of the die.

[0008] The present invention provides a method and apparatus for manufacturing fibers that allows for the simultaneous spinning of fibers of different diameters using a single die, by adjusting the rotation speed of the polymer extruded from multiple extrusion holes while stretching the fibrous polymer extruded from each extrusion hole using a die equipped with multiple extrusion holes. Furthermore, by bundling these fibers of different diameters, fiber bundles with various properties can be obtained. [Means for solving the problem]

[0009] [1] The present invention solves the above problem and is a method for producing fibers by stretching a fibrous polymer extruded from a nozzle having a plurality of extrusion holes, The fibrous polymer discharged from the discharge hole is stretched while revolving around a straight line extending from the discharge hole in the direction of polymer discharge, In two or more of the above-mentioned discharge holes, the orbital speed of the fibrous polymer discharged from each of the said discharge holes is made different.

[0010] [2] The present invention, which solves the above problems, is another embodiment of a method for producing fibers by stretching a fibrous polymer extruded from a nozzle having a plurality of discharge holes, The fibrous polymer discharged from the discharge hole is stretched while revolving around a straight line extending from the discharge hole in the direction of polymer discharge, The nozzle has multiple rows of discharge holes, each row in which multiple discharge holes are arranged in a single line. In two or more rows of the discharge holes, the orbital speed of the fibrous polymer discharged from the discharge holes within each row of discharge holes is differentiated between the rows of discharge holes.

[0011] [3] In the fiber manufacturing method described in [1] or [2] above, it is preferable that the difference in orbital speed is 100 times / second or more.

[0012] [4] Another embodiment of the present invention for manufacturing fibers that solves the above problems is a method for manufacturing fibers by stretching a fibrous polymer extruded from a die having a plurality of extrusion holes, The fibrous polymer discharged from the discharge hole is stretched while rotating by applying a torsional force that rotates it around a straight line extending from the discharge hole in the direction of polymer discharge. In two or more of the above-mentioned discharge holes, the rotation speed of the fibrous polymer discharged from each of the said discharge holes is made different.

[0013] [5] Another embodiment of the present invention for manufacturing fibers that solves the above problems is a method for manufacturing fibers by stretching a fibrous polymer extruded from a die having a plurality of extrusion holes, The fibrous polymer discharged from the discharge hole is stretched while rotating by applying a torsional force that rotates it around a straight line extending from the discharge hole in the direction of polymer discharge. The nozzle has multiple rows of discharge holes, each row in which multiple discharge holes are arranged in a single line. In the above-described discharge hole rows having two or more columns, a difference is provided in the rotational speed of the fibrous polymer discharged from the discharge holes in each of the discharge hole rows between the discharge hole rows.

[0014] [6] In the method for producing the fiber according to [4] or [5] above, it is preferable that the difference in the rotational speed is 100 revolutions per second or more.

[0015] [7] The fiber production apparatus of the present invention for solving the above problems is an apparatus for producing a fiber by stretching a fibrous polymer, a die having a plurality of discharge holes for discharging the fibrous polymer, and an air flow nozzle for injecting an air flow, disposed around the fibrous polymer discharged from the discharge hole, and includes: By forming a swirling flow by the air flow injected from the air flow nozzle, the fibrous polymer is revolved around a straight line extending in the polymer discharge direction from the discharge hole, All the air flow nozzles assigned to one discharge hole are set as one set, and it has flow rate control means capable of adjusting the flow rate of the air flow injected from the air flow nozzle for each set.

[0016] [8] Another aspect of the fiber production apparatus of the present invention for solving the above problems is an apparatus for producing a fiber by stretching a fibrous polymer, <​​​​​​​​​​​ [9]Another aspect of the fiber manufacturing apparatus of the present invention for solving the above problems is an apparatus for manufacturing fibers by stretching a fibrous polymer, a die having a plurality of discharge holes for discharging the fibrous polymer, and an air flow nozzle for injecting an air flow, disposed around the fibrous polymer discharged from the discharge holes. By forming a swirling flow by the air flow injected from the air flow nozzle, a torsional force is applied to rotate the fibrous polymer about an axis of a straight line extending in the polymer discharge direction from the discharge holes, thereby causing the fibrous polymer to rotate on its own axis. All of the air flow nozzles assigned to one discharge hole are regarded as one set, and temperature control means is provided for adjusting the temperature of the air flow injected from the air flow nozzles for each set.

[0018]

[10] Another aspect of the fiber manufacturing apparatus of the present invention for solving the above problems is an apparatus for manufacturing fibers by stretching a fibrous polymer, a die having a plurality of discharge holes for discharging the fibrous polymer, and an air flow nozzle for injecting an air flow, disposed around the fibrous polymer discharged from the discharge holes. By forming a swirling flow by the air flow injected from the air flow nozzle, a torsional force is applied to rotate the fibrous polymer about an axis of a straight line extending in the polymer discharge direction from the discharge holes, thereby causing the fibrous polymer to rotate on its own axis. The die has a plurality of rows of discharge holes in which the plurality of discharge holes are arranged in a line, All of the air flow nozzles assigned to each of the plurality of discharge holes in one discharge hole row are regarded as one set, and temperature control means is provided for adjusting the temperature of the air flow injected from the air flow nozzles for each set.

[0019] In the present invention, the "polymer discharge direction" means the direction in which the fibrous polymer is discharged from the discharge holes. In the present invention, the "swirling flow" means an air flow having a flow that continuously rotates in the circumferential direction around a point in a plane perpendicular to the longitudinal direction of the fiber. In this invention, "torsional force" refers to a force acting on the fiber surface such that a moment is generated in the rotational direction around the center of the fiber cross-section as an axis in a plane perpendicular to the longitudinal direction of the fiber. In the present invention, the "discharge section" refers to a space extending downstream from the discharge hole of the nozzle in the polymer discharge direction, having the same cross-sectional area as the discharge hole, and being a cylindrical space with a length of 0.5 mm downstream from the discharge hole in the polymer discharge direction.

[0020] In this invention, "all airflow nozzles assigned to one discharge port" refers to all airflow nozzles that inject airflow onto the fibrous polymer discharged from one discharge port. For example, in an embodiment where airflow is injected from three airflow nozzles onto the fibrous polymer discharged from one discharge port, this refers to these three airflow nozzles, and these three airflow nozzles constitute one set.

[0021] In the present invention, "all the airflow nozzles assigned to each of the multiple discharge holes in a single row of discharge holes" refers to airflow nozzles that inject airflow onto the fibrous polymer discharged from each of the multiple discharge holes in a single row of discharge holes. For example, in a configuration where there are two discharge holes in a single row of discharge holes, and three airflow nozzles are assigned to each discharge hole, this refers to a total of six airflow nozzles, and these six airflow nozzles constitute one set. [Effects of the Invention]

[0022] According to the present invention, by using a die equipped with multiple discharge holes and adjusting the rotation speed of the fibrous polymer discharged from each discharge hole, fibers of different diameters can be manufactured simultaneously from a single die. [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is a schematic cross-sectional view showing one embodiment of the fiber manufacturing apparatus of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 6] Figure 6 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 7] Figure 7 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 8] Figure 8 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 9] Figure 9 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 10] Figure 10 is a schematic cross-sectional view showing an embodiment of a conventional fiber bundle manufacturing apparatus. [Figure 11] Figure 11 is a schematic cross-sectional view showing an embodiment of a conventional fiber manufacturing apparatus. [Figure 12] Figure 12 is a schematic cross-sectional view showing the configuration of an apparatus for producing a sheet using the fiber manufacturing apparatus of the present invention. [Figure 13] Figure 13 is a schematic cross-sectional view showing an example of a device configuration for the fiber manufacturing apparatus of the present invention, in which a single fiber is stretched by revolving it in a swirling flow. [Figure 14] Figure 14 is a schematic cross-sectional view showing an example of a device configuration for the fiber manufacturing apparatus of the present invention, in which a single fiber is stretched by revolving it in a swirling flow. [Figure 15] Figure 15 is a schematic cross-sectional view showing an example of a device configuration for the fiber manufacturing apparatus of the present invention, in which a single fiber is stretched by revolving it in a swirling flow. [Figure 16] Figure 16 is a schematic cross-sectional view showing an example of a device configuration for the fiber manufacturing apparatus of the present invention, in which a single fiber is stretched by revolving it in a swirling flow. [Figure 17]Figure 17 is a schematic cross-sectional view showing an example of the configuration of the fiber manufacturing apparatus of the present invention, in which a single fiber is rotated on a rotating roller and stretched. [Figure 18] Figure 18 is a schematic cross-sectional view showing an embodiment of a conventional fiber manufacturing apparatus. [Figure 19] Figure 19 is a schematic cross-sectional view showing an embodiment of a conventional fiber manufacturing apparatus. [Figure 20] Figure 20 is a schematic diagram illustrating the installation angle of the airflow nozzle. [Figure 21] Figure 21 is a schematic diagram illustrating the installation angle of the airflow nozzle. [Figure 22] Figure 22 is a schematic diagram illustrating the direction of the jet stream ejected from the airflow nozzle. [Figure 23] Figure 23 is a schematic diagram showing the configuration of the airflow closure member in the fiber manufacturing apparatus of the present invention. [Figure 24] Figure 24 is a schematic diagram showing the form of swirling flow formation in the space of the airflow closure member in the fiber manufacturing apparatus of the present invention. [Figure 25] Figure 25 is a schematic diagram showing an example of the configuration of an airflow closure member in the fiber manufacturing apparatus of the present invention. [Figure 26] Figure 26 is a schematic diagram showing the centrifugal force generated when the fibers in the discharge section are revolved. [Figure 27] Figure 27 is a schematic diagram of the molecular arrangement at the dispensing section. [Figure 28] Figure 28 is a schematic cross-sectional view illustrating a method for measuring the rotation speed of a single fibrous polymer. [Figure 29] Figure 29 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 30] Figure 30 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 31] Figure 31 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Figure 32] Figure 32 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. [Modes for carrying out the invention]

[0024] Hereinafter, various embodiments of the fiber manufacturing apparatus of the present invention and methods for manufacturing fibers using the manufacturing apparatus will be described in detail with reference to the drawings. Figure 1 is a schematic cross-sectional view showing one embodiment of the fiber manufacturing apparatus of the present invention. Figures 2 to 9 are schematic cross-sectional views of another embodiment of the fiber manufacturing apparatus of the present invention. Figures 10 and 11 are schematic cross-sectional views of an embodiment of a conventional fiber manufacturing apparatus. Figures 13 to 17 are schematic cross-sectional views showing an embodiment in which a single fiber is drawn from a polymer extruded from a single extrusion hole in the fiber manufacturing apparatus of the present invention. In each drawing, Figures A, B, and C shown on the right side of the drawing are cross-sectional views along the dashed lines A, B, and C in the embodiment shown on the left side of the drawing. These figures are schematic diagrams intended to accurately convey the essential points of the present invention, and the figures have been simplified. The spinning apparatus of the present invention is not particularly limited, and dimensional ratios, etc., can be changed according to the embodiment. Also, the polymer 3 after being extruded from the extrusion hole 2 in each figure is depicted in a larger size to clearly illustrate the torsional force.

[0025] First, the stretching phenomenon of fiber 4 in the fiber manufacturing method of the present invention will be explained. Figure 18 is a schematic diagram of a conventional fiber manufacturing apparatus 100G, commonly known as meltblown fiber. As shown in the figure, a jet stream 11 is directly injected from two opposing nozzles onto a single fiber 4 formed from polymer 3 extruded from an extrusion hole 2, and an airflow parallel to the polymer extrusion direction is applied to the fiber 4, thereby applying a stretching force 16. The polymer 3 is extruded from the extrusion hole 2 in a low viscosity state, and the stretching force 16 is applied by friction between the fiber 4 formed from the polymer 3 and the airflow, causing the fiber 4 to stretch in the polymer extrusion direction. At this time, increasing the speed of the jet stream 11 increases the velocity difference between the yarn and the jet stream, increasing friction and thus increasing the stretching force. However, in reality, increasing the speed of the jet stream 11 increases yarn oscillation in the stretching section, thus suppressing the increase in tensile force. For this reason, there are limitations to promoting stretching by applying airflow in a parallel direction. Also, when the fiber is stretched, the molecular orientation of the polymer 3 within the fiber 4 is aligned along the longitudinal direction of the fiber. This promotes molecular orientation within the fiber 4, making the polymer 3 less susceptible to deformation in the orientation direction, and thus less prone to stretching. For this reason, there are limitations to reducing the diameter of the fiber 4 using conventional manufacturing methods.

[0026] The inventors, after diligent research to solve the above problems, focused on the rotational motion of the fiber 4 during stretching. As described above, in conventional stretching methods, the range of fiber 4 diameters that can be formed with a single die is limited due to the limitations of the stretching force 16 caused by friction and the suppression of stretching due to molecular orientation. Therefore, the inventors considered that by causing the fiber 4 to revolve or rotate at high speed immediately after extrusion, the stretching of the fiber 4 can be promoted, thereby expanding the range of fiber 4 diameters that can be formed with a single die, and ultimately allowing for arbitrary control of the fiber 4 diameter.

[0027] Referring to Figure 26, the effect of revolving the fiber on stretching will be explained. As described above, in meltblowing, an airflow is passed over the fiber 4 in a direction parallel to the polymer discharge direction, and the frictional force generated between the fiber and the airflow stretches the fiber 4. As shown in Figure 26, when the fiber 4 is revolved at the discharge section, a centrifugal force 27 acts in the radial direction of the revolution outward from the center of rotation 28. Therefore, the centrifugal force 27 becomes a force that stretches the fiber 4. Furthermore, if the centrifugal force 27 applied to the fiber 4 is F, the mass of the fiber affecting the centrifugal force 27 is m, the angular velocity of rotation is ω, and the radius of rotation is r, then the centrifugal force F is proportional to the square of the angular velocity of the airflow rotation, as shown in equation (A). F=mω 2 r ···(A) As the fiber 4 revolves, the centrifugal force 27 changes significantly according to the rotational speed. Therefore, by changing the rotational speed of the fiber 4, the diameter of the fiber 4 can be changed significantly.

[0028] Next, referring to Figure 27, we will explain the effect of spinning the fiber on stretching, or more specifically, the relationship between the molecular orientation of polymer 3 and stretching. Molecular chains 22 exist inside polymer 3, and when polymer 3 is extruded from the extrusion hole 2 during spinning, they are aligned in the longitudinal direction of the fiber 4, and are further aligned by being stretched by the stretching force 16, causing the molecular chains 22 to be oriented as shown in Figure (a). The orientation of the molecular chains 22 inside polymer 3 eliminates the room for deformation of the molecular chains 22 in the orientation direction, and the stretching of polymer 3 in the orientation direction is suppressed. In other words, in conventional stretching methods, the stretching force 16 is applied only in the longitudinal direction to stretch polymer 3, so after the molecular chains 22 are oriented in the longitudinal direction by the stretching of polymer 3, further stretching in the longitudinal direction is suppressed.

[0029] Therefore, we considered that disrupting the orientation of the molecular chains 22 during stretching might be effective in preventing stretching inhibition. We investigated disrupting the orientation of the molecular chains 22 within the polymer 3 by applying a force that moves the polymer 3 in a direction perpendicular to the longitudinal direction, in addition to the stretching force 16 in the longitudinal direction during stretching. As a means to achieve this, we focused on a method of applying a torsional force in a direction that rotates the fiber 4 around the center of the cross-section perpendicular to the discharge direction, i.e., in a direction that causes it to rotate on its own. As the fiber 4 rotates, the polymer 3 moves in the cross-section of the fiber 4, and the orientation of the molecular chains 22 is disrupted as shown in Figure (b). In particular, when the polymer 3 is in a molten state, the molecular chains 22 are in a state where they can easily move, so by rotating the fiber 4, the effect of disrupting the molecular chains 22 can be obtained more effectively. In the extrusion section of polymer 3 where molecules within polymer 3 are oriented, and in the stretching section of fiber 4, a continuous torsional force is applied perpendicular to the longitudinal direction of fiber 4, which is the stretching direction, causing fiber 4 to rotate at high speed. This disrupts the molecular orientation in the longitudinal direction, thereby stretching fiber 4. As fiber 4 rotates, the molecular orientation changes significantly according to the rotation speed, so the diameter of fiber 4 can be significantly changed by changing the rotation speed.

[0030] Based on these principles, the stretched state of the fiber 4 can be significantly altered by causing it to revolve or rotate after being extruded from the extrusion hole 2. Therefore, when spinning fibers 4 with a die 1 equipped with two or more extrusion holes 2, the diameter of the fiber 4 formed by a single die can be controlled for each extrusion hole 2 by controlling the rotational speed of the revolvement (see Figure 1) or rotation (see Figure 2) of each fiber 4 formed at each extrusion hole 2. As a result, fibers 4 of different diameters can be formed simultaneously from a single die 1.

[0031] In the conventional manufacturing method shown in Figure 18, the stretching force 16 is applied only by longitudinal frictional force caused by the collision of a parallel airflow with the fiber 4. Therefore, it is not possible to apply centrifugal force 27 due to revolution or torsional force due to rotation to the fiber 4, making it difficult to significantly change the fiber diameter by changing the stretching force 16. Consequently, when spinning the fiber 4 with a die 1 equipped with two or more discharge holes 2, it is difficult to form fibers of different diameters simultaneously from a single die 1.

[0032] If the rotational speed of the fiber 4 is too slow, the centrifugal force 27 generated by the revolution will be small, and the effect of increasing the stretching force 16 and reducing the diameter of the fiber 4 will not be sufficiently obtained. For this reason, the rotational speed of the fiber 4 is preferably 100 revolutions / second or more, and more preferably 500 revolutions / second or more.

[0033] If the difference in the rotational speed of the fibers 4 discharged from different discharge holes 2 is too small, the difference in the diameter of the fibers 4 that can be formed with one die 1 will be small. Therefore, the difference in the rotational speed of the fibers 4 discharged from different discharge holes 2 is preferably 100 revolutions / second or more, and more preferably 1000 revolutions / second or more.

[0034] If the rotation speed of the fiber 4 is too slow, the torsional force acting on the molecules in the fiber 4 will be small, and the effect of disrupting the molecular arrangement by the torsional force 17 will not be sufficiently obtained, and consequently, the effect of promoting stretching will not be obtained. For this reason, the rotation speed of the fiber 4 is preferably 100 times / second or more, and more preferably 500 times / second or more.

[0035] If the difference in rotational speed of the fibers 4 discharged from different discharge holes 2 is too small, the difference in diameter of the fibers 4 that can be formed with one die becomes small. Therefore, the difference in rotational speed of the fibers 4 discharged from different discharge holes 2 is preferably 100 times / second or more, and more preferably 1000 times / second or more.

[0036] Since it is difficult to measure the rotation speed of fiber 4 during spinning, the rotation speed in this invention is the value obtained by measuring the rotation speed of fiber 4 while it is at rest, as explained in "(3) Fiber rotation speed (times / second)" in the examples described later. Note that the viscosity of the fiber is not taken into consideration in this measurement method.

[0037] Next, we will describe the manufacturing equipment necessary to realize this manufacturing method. First, let's specifically explain the configuration of the device that revolves a single fiber 4. One method of revolving the fiber 4 is to inject a swirling flow 12 into the fiber 4, thereby causing the fiber 4 to revolve within the swirling flow 12.

[0038] The fiber manufacturing apparatus of the present invention will be described with reference to Figure 13. Figure 13 shows one embodiment of a fiber manufacturing apparatus that revolves fibers 4 by a swirling flow 12. The fiber manufacturing apparatus 100A shown in Figure 13 consists of a nozzle 1 having a discharge hole 2 for discharging polymer 3, which is the raw material for fibers 4; an airflow nozzle 5 arranged around the polymer 3 discharged from the discharge hole 2 and injecting a jet flow 11; an airflow closure member 6 arranged below the polymer discharge direction of the discharge hole 2 and surrounding a space 7 through which the polymer 3 and fibers 4 pass; and a winding roller 14 for winding up the fibers 4. The jet flow 11 is injected from the airflow nozzle 5 toward the wall 8 of the airflow closure member 6, and a swirling flow 12 is formed in the space 7. Then, the fibers 4 obtained from the polymer 3 discharged from the nozzle 1 are passed through this swirling flow 12 and then wound up by the winding roller 14.

[0039] Note that Figure 13 and Figures 14-17, described below, are diagrams illustrating the configuration of a device that revolves or rotates a single fiber, and therefore each nozzle 1 has only one discharge hole 2. However, the actual fiber manufacturing apparatus of the present invention has multiple discharge holes 2 in each nozzle 1.

[0040] Referring to Figure 23, the specific configuration of the airflow closure member 6 will be explained. The airflow closure member 6 is composed of a cylindrical wall 8, and the space 7 surrounded by the wall 8 serves as the airflow passage. The space 7 is a through hole that penetrates from one end face to the other end face of the airflow closure member 6. The space 7 does not need to be surrounded by the wall 8 for its entire length; it is sufficient if it is surrounded by the wall 8 for a portion of its length.

[0041] The airflow through the airflow closure member 6 will be explained with reference to Figures 22 and 24. Figure 24 is a schematic diagram showing the form of swirling flow formation within the space 7 enclosed by the airflow closure member 6, and Figure 22 is a schematic diagram explaining the injection direction of the jet stream 11 from the airflow nozzle 5. As shown in Figure 24, a high-speed swirling flow 12 is formed by injecting a jet stream 11 with a velocity component in the circumferential direction of the fiber 4 into the space 7 so as to collide with the wall 8 of the airflow closure member 6 from the airflow nozzle 5. Here, as shown in Figure 22, the injection direction of the jet stream 11 is defined as the radial direction from the tip of the airflow nozzle 5 toward the center of the fiber 4, and the circumferential direction at a 90° angle from the radial direction.

[0042] Refer to Figure 13 again. As shown in the cross-sectional view along the dashed line A, a jet stream 11 with a velocity component in the circumferential direction of the fiber 4 is injected from the airflow nozzle 5 so as to collide with the wall 8 of the airflow closure member 6. As a result, a swirling flow 12 is formed around the fiber 4, as shown in the cross-sectional view along the dashed line B. As the fiber 4 passes through the swirling flow 12, the fiber 4 revolves at high speed and a centrifugal force 27 acts on it. This applies an extension force 16 acting in the longitudinal direction of the fiber 4 and a centrifugal force 27 to the fiber 4, causing the fiber 4 to stretch. This stretching method promotes the reduction of the fiber diameter, so that a stable small-diameter fiber 4 can be obtained.

[0043] Figure 19 is a schematic cross-sectional view showing an embodiment of a conventional fiber manufacturing apparatus. In a method in which a jet stream 11 is directly injected from an airflow nozzle 5 into an open space without surrounding walls 8, such as the fiber manufacturing apparatus 100H shown in Figure 19, it is difficult to form a swirling flow 12 because the jet stream 11 expands and diffuses immediately after injection. In other words, in order to generate a swirling flow 12 that allows the fibers 4 to revolve sufficiently, it is necessary to suppress the diffusion of the jet stream 11. Therefore, it is preferable to install an airflow closure member 6 in the fiber manufacturing apparatus of the present invention. By installing the airflow closure member 6, the diffusion of the jet stream 11 can be effectively suppressed, and the diameter of the fibers 4 can be reduced.

[0044] Figure 20 is a schematic diagram illustrating the installation angle of the airflow nozzle 5. If the angle α between the direction of travel of the fiber 4 and the direction of injection of the injection flow 11 is small, the rotational speed component of the swirling flow 12 tends to weaken. Conversely, if the angle α is greater than 90°, the airflow is injected in the opposite direction to the direction of travel of the fiber 4, resulting in an airflow in the opposite direction to the stretching direction of the fiber 4, which tends to hinder the stretching of the fiber 4. Therefore, an angle α of 5° or more and 90° or less is preferable.

[0045] Figure 21 is a schematic diagram illustrating the installation angle of the airflow nozzle 5 in a cross-section perpendicular to the direction of fiber travel. If the angle β between the straight line connecting the center of the discharge part of the airflow nozzle 5 and the center of the fiber 4 (the shortest straight line connecting the airflow nozzle 5 and the fiber 4) and the injection direction of the jet 11 is small, the jet 11 will directly collide with the fiber 4, making it difficult to form a swirling flow 12. Conversely, if the angle β is large, the jet will be injected in the opposite direction to the fiber 4, making it easy for energy loss to occur. Therefore, an angle β of 5° to 90° is preferable.

[0046] Figure 14 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus according to the present invention. In the fiber manufacturing apparatus 100A of Figure 13, the jet stream 11 is supplied by one airflow nozzle 5 and a swirling flow 12 is formed inside the airflow closing member 6. As in the fiber manufacturing apparatus 100B of Figure 14, by installing many airflow nozzles 5, the jet stream 11 can be dispersed and supplied, and the swirling flow 12 can be formed more stably. Therefore, it is preferable to use two or more airflow nozzles 5 for jetting, and more preferably three or more for jetting.

[0047] When using two or more airflow nozzles 5, a smooth swirling flow 12 can be formed by supplying the jet stream 11 evenly, allowing the fibers 4 to revolve continuously. Therefore, when using two or more airflow nozzles 5, it is preferable to evenly arrange the airflow nozzles 5 on the circle shown by the dotted line in Figure 14A and inject the jet stream 11 in the circumferential direction of this circle.

[0048] In order to form a swirling flow 12 in the space 7 of the airflow closing member 6, it is preferable that the cross-sectional area of ​​the airflow passage of the airflow nozzle 5 is smaller than the cross-sectional area of ​​the space 7. The cross-sectional shape of the airflow passage of the airflow nozzle 5 is not limited to circular or rectangular, but can be any cross-sectional shape.

[0049] Figure 15 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. In the fiber manufacturing apparatus 100A of Figure 13, the horizontal cross-sectional area of ​​the space of the airflow closure member 6 is constant from the upper opening 9 to the lower opening 10. However, in order to take in the jet flow 11 from the airflow nozzle 5 into the space 7 of the airflow closure member 6, it is easier to take in the air if the cross-sectional area of ​​the space 7 at the upper opening 9 of the airflow closure member 6 is large, and the airflow within the airflow closure member 6 is accelerated and the swirling flow 12 is accelerated if the cross-sectional area of ​​the space 7 at the lower opening 10 is small. Therefore, it is preferable to have a structure in which the cross-sectional area of ​​the space 7 decreases from the upper opening 9 to the lower opening 10, as shown in the fiber manufacturing apparatus 100C of Figure 15.

[0050] The center of the swirling flow 12 formed by the airflow closure member 6 lies on the axis extending from the discharge hole 2 in the direction of polymer 3 discharge, allowing the fibers 4 to revolve efficiently. Therefore, it is preferable that the central axis of the spiral of the swirling flow 12 coincides with the axis extending from the discharge hole 2 in the direction of polymer 3 discharge.

[0051] The airflow closure member 6 is a member that forms a swirling flow 12 from the jet flow 11. As shown in the fiber manufacturing apparatus 100A in Figure 13, the swirling flow 12 formed on approximately half of the inner wall of the airflow closure member 6 may be made to collide with the fibers 4, or as shown in the fiber manufacturing apparatus 100C in Figure 15, the swirling flow 12 may be made to collide with the fibers 4 only from the vicinity of the lower opening 10 of the airflow closure member 6.

[0052] Figure 25 is a schematic diagram showing examples of the form of the airflow closure member 6 in the fiber manufacturing apparatus of the present invention. As shown in the example in Figure 25, the airflow closure member 6 can take various forms. Figure (a) shows that the horizontal cross-section of the space 7 inside the airflow closure member 6 is circular and of a constant shape. Figure (b) shows that the horizontal cross-section of the space 7 is circular and of a tapered shape. Figure (c) shows that the horizontal cross-section of the space 7 is rectangular and of a constant shape. Figure (d) shows that the horizontal cross-section of the space 7 is circular and of a shape in which a passage is formed in the wall. The form of the airflow closure member 6 may be other than those shown in Figures (a) to (d).

[0053] Figure 16 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. Note that the winding roller 14 is not shown in Figure 16. In the fiber manufacturing apparatus 100A of Figure 13, the supply of the swirling flow 12 may become unstable due to the influence of gases other than the jet flow 11 at the upper opening 9 of the airflow closure member 6. Therefore, as in the fiber manufacturing apparatuses 100D and 100E shown in Figure 16, the upper opening 9 of the airflow closure member 6 may be blocked except for the air injection port of the airflow nozzle 5.

[0054] If the cross-sectional area of ​​the space 7 in the airflow closure member 6 is too narrow, the fibers 4 tend to adhere to the wall surface of the airflow closure member 6 when they pass through, which can easily worsen spinnability. On the other hand, if the cross-sectional area is too wide, the swirling flow 12 slows down, and the swirling force required to revolve the fibers 4 tends to weaken. Therefore, the cross-sectional area at the smallest point of the space 7 should be 1 mm². 2 100mm or more 2 The following is preferable:

[0055] In a device configuration where the fibers are revolved by a swirling flow 12, the fibers may twist and rotate in conjunction with their revolving motion.

[0056] Next, we will specifically describe the configuration of a device that rotates a single fiber using a roller. One way to rotate the fiber 4 is to bring the fiber 4 into direct contact with a rotating roller and apply a torsional force to the fiber 4. Figure 17 is a schematic cross-sectional view showing another embodiment of the fiber manufacturing apparatus of the present invention. In this fiber manufacturing apparatus 100F, the fibers are brought into direct contact with a rotating roller 13 to apply a torsional force to the fibers. The fiber manufacturing apparatus 100F consists of a die 1 having an discharge hole 2 for discharging polymer 3, a rotating roller 13 positioned to contact the stretched fibers 4 of polymer 3 discharged from the discharge hole 2, and a winding roller 14 for winding up the fibers 4. In this apparatus 100F, the fibers 4 obtained from polymer 3 discharged from the die 1 are brought into contact with the rotating roller 13, and the rotating roller 13 is rotated in this state to apply a torsional force 17 to the fibers 4, and the stretched fibers 4 are wound up by the winding roller 14. A stretching force 16 acting in the longitudinal direction and a torsional force 17 acting in a direction perpendicular to the longitudinal direction are applied to the fibers 4 to stretch them. This promotes the reduction of the diameter of the fibers 4, so that thin fibers 4 can be obtained stably.

[0057] In the fiber manufacturing apparatus 100F, the rotating roller 13 rotates at high speed, so the fibers 4 may collide with the corners of the side surface of the rotating roller 13 while moving, causing the fibers 4 to be cut. Therefore, it is preferable that the corners of the side surface of the rotating roller 13 be curved.

[0058] Since the rotating roller 13 comes into contact with the moving fibers 4, continuous operation will cause wear on the side surface of the rotating roller 13 that comes into contact with the fibers 4. Therefore, it is preferable that the material of the side surface of the rotating roller 13 be ceramic.

[0059] In Figure 17, the axis of the rotating roller 13 is positioned parallel to the direction of travel of the fiber 4. However, as long as a torsional force 17 can be applied to the fiber 4, it may be positioned at an angle of 0° to 85° from the direction parallel to the direction of travel of the fiber 4.

[0060] Next, we will describe a case where the device is configured to rotate the fibers 4 using a swirling flow 12. First, let's explain the effect of temperature and rotation speed on fiber 4. Generally, the viscosity of molten polymer is temperature-dependent; higher temperatures result in lower viscosity, and lower temperatures result in higher viscosity. Fibers with lower viscosity are more easily deformed and twisted. Conversely, fibers with higher viscosity are less easily deformed and twisted. In other words, increasing the temperature of fiber 4 also promotes its rotation. Since the viscosity of fiber 4 changes with temperature, the diameter of fiber 4 can be changed by changing its temperature. Furthermore, changes in the temperature of fiber 4 affect not only its ability to twist but also its ease of stretching in the extrusion direction.

[0061] Based on this principle, when spinning fibers 4 with a die 1 equipped with two or more discharge holes 2, the diameter of the fiber 4 formed by a single die can be controlled for each discharge hole 2 by controlling the temperature of each fiber 4 formed at each discharge hole 2. To control the temperature of the fiber 4, it is effective to control the temperature of the airflow blown onto the fiber 4. In a device configuration in which the fiber 4 is rotated by a swirling flow 12, the fiber 4 is often stretched along with its revolution.

[0062] Now, let's describe the configuration of the apparatus that realizes the manufacturing method of the present invention using the apparatus configuration described above. In an apparatus that revolves the fiber 4, controlling the velocity of the airflow colliding with the fiber 4 is effective in controlling the revolving velocity.

[0063] Figure 3 shows a configuration in which all airflow nozzles 5 assigned to one discharge hole 2 are treated as a set, and a flow path control means 23 is provided to adjust the airflow injected from each set of airflow nozzles 5. Specifically, one nozzle 1 has four discharge holes 2, and one airflow nozzle 5 injects airflow to the fibers 4 discharged from each discharge hole 2. Each of the four airflow nozzles 5 is equipped with one flow path control means 23 that can control the airflow rate supplied from the airflow supply member 24. With this configuration, the airflow rate supplied from the airflow supply member 24 to the airflow nozzles 5 can be adjusted for each discharge hole 2 by the flow rate control means 23. By adjusting the airflow rate, the flow velocity of the swirling flow 12 can be adjusted, the orbital speed of the fibers 4 formed at each discharge hole 2 can be controlled, and the average fiber diameter of the fibers 4 can be controlled. The number of discharge holes 2 provided by one nozzle 1 may not be four, and there may be multiple airflow nozzles 5 that inject airflow to the fibers 4 discharged from one discharge hole 1.

[0064] Figure 4 shows a configuration in which all the airflow nozzles 5 assigned to each of the multiple discharge holes 2 within a single discharge hole row are treated as a set, and a flow rate control means 23 is provided to adjust the flow rate of the airflow injected from the airflow nozzles 5 for each set. Specifically, one nozzle 1 has four discharge holes 2, and two discharge holes 2 form one row of discharge holes, with one airflow nozzle 5 injecting airflow to the fibers 4 discharged from each discharge hole 2. Two airflow nozzles 5 within each discharge hole row are connected to one airflow path 25, and each of the two airflow paths 25 is equipped with one flow path control means 23 that can control the airflow rate supplied from the airflow supply member 24.

[0065] With this configuration, the airflow rate supplied from the airflow supply member 24 to the airflow passage 25 can be adjusted by the flow rate control means 23, and the airflow rate can be adjusted for each set of airflow nozzles 5 connected to the airflow passage 25. In other words, the airflow rate supplied from the airflow supply member 24 to the airflow nozzles 5 can be adjusted by the flow rate control means 23 for each row of discharge holes. By adjusting the airflow rate, the flow velocity of the swirling flow 12 can be adjusted, the orbital speed of the fibers 4 formed at each discharge hole 2 can be controlled for each row of discharge holes, and the average fiber diameter of the fibers 4 can be controlled for each row of discharge holes. Although the average fiber diameter of the fibers 4 cannot be controlled individually, the number of flow rate control means 23 can be reduced, thus simplifying the device. The number of discharge holes 2 in one nozzle 1 may be less than four, the number of discharge holes 2 in one row of discharge holes may be less than two, and there may be multiple airflow nozzles 5 that inject airflow onto the fibers 4 discharged from one discharge hole 1.

[0066] In a device that uses rollers to rotate fibers 4, controlling the rotation speed is effective by controlling the rotation speed of the rotating roller 13 that contacts the fibers 4. Figure 5 shows a configuration in which one rotating roller 13 is installed to contact each fiber 4 formed at each discharge hole 2. By controlling the rotation speed of each rotating roller 13, the rotation speed of each fiber 4 can be controlled, and the average fiber diameter of the fibers 4 can be controlled.

[0067] In a device that uses airflow to rotate a fiber 4, controlling the temperature of the airflow impacting the fiber 4 is effective in controlling the rotation speed of the fiber 4. In the configuration described below, in which the fiber 4 is rotated and stretched by a swirling flow 12, the fiber 4 is often stretched while also revolving.

[0068] Figure 29 shows a configuration in which all airflow nozzles 5 assigned to one discharge hole 2 are treated as a set, and a temperature control means 29 is provided to adjust the temperature of the airflow injected from the airflow nozzles 5 for each set. Specifically, one nozzle 1 has four discharge holes 2, and one airflow nozzle 5 injects airflow to the fibers 4 discharged from each discharge hole 2. Each of the four airflow nozzles 5 is equipped with one temperature control means 29 that can control the temperature of the air supplied from the airflow supply member 24.

[0069] With this configuration, the temperature of the air supplied from the airflow supply member 24 to the airflow nozzle 5 can be adjusted for each discharge hole 2 by the temperature control means 29. By adjusting the air temperature, the temperature of the fibers 4 can be adjusted, the viscosity of the fibers 4 can be controlled, and the average fiber diameter of the fibers 4 can be controlled. The number of discharge holes 2 in one nozzle 1 does not have to be four, and there may be multiple airflow nozzles 5 that inject airflow onto the fibers 4 discharged from one discharge hole 1.

[0070] Figure 30 shows a configuration in which all the airflow nozzles 5 assigned to each of the multiple discharge holes 2 within a single discharge hole row are considered as one set, and a temperature control means 29 is provided to adjust the temperature of the airflow injected from the airflow nozzles 5 for each set. Specifically, one nozzle 1 has four discharge holes 2, and two discharge holes 2 form one row of discharge holes, with one airflow nozzle 5 injecting airflow to the fibers 4 discharged from each discharge hole 2. Two airflow nozzles 5 within each discharge hole row are connected to one airflow passage 25, and each of the two airflow passages 25 is equipped with one temperature control means 29 that can control the temperature of the air supplied from the airflow supply member 24.

[0071] With this configuration, the temperature of the air supplied from the airflow supply member 24 to the airflow passage 25 can be adjusted by the temperature control means 29, and the airflow temperature can be adjusted for each set of airflow nozzles 5 connected to the airflow passage 25. In other words, the temperature of the air supplied from the airflow supply member 24 to the airflow nozzles 5 can be adjusted by the temperature control means 29 for each row of discharge holes. By adjusting the air temperature, the temperature of the fibers 4 can be adjusted, the viscosity of the fibers 4 formed at each discharge hole 2 can be controlled for each row of discharge holes, and the average fiber diameter of the fibers 4 can be controlled for each row of discharge holes. Although the average fiber diameter of the fibers 4 cannot be controlled individually, the number of temperature control means 29 can be reduced, thus simplifying the device. The number of discharge holes 2 in one nozzle 1 may be less than four, the number of discharge holes 2 in one row of discharge holes may be less than two, and there may be multiple airflow nozzles 5 that inject airflow onto the fibers 4 discharged from one discharge hole 1.

[0072] Figure 31 shows a configuration in which all airflow nozzles 5 assigned to one discharge hole 2 are treated as one set, and the device is equipped with both a flow rate control means 23 that can adjust the flow rate of the airflow ejected from the airflow nozzles 5 for each set, and a temperature control means 29 that can adjust the temperature of the airflow for each set. Furthermore, Figure 32 shows a configuration in which all airflow nozzles 5 assigned to each of the multiple discharge holes 2 in a single row of discharge holes are treated as one set, and the device is equipped with both a flow rate control means 23 that can adjust the flow rate of the airflow ejected from the airflow nozzles 5 for each set, and a temperature control means 29 that can adjust the temperature of the airflow for each set. In these configurations, in a device configuration that stretches the fibers 4 by revolving and rotating them using a swirling flow 12, by providing both a flow rate control means 23 and a temperature control means 29, both the revolving speed and the rotating speed can be adjusted, thus allowing control of the average fiber diameter of the fibers 4 over a wider range.

[0073] Next, a common preferred embodiment of the present invention will be described. Refer to Figures 6 and 7. The method for recovering the fibers 4 is not limited to the winding roller 10 shown in Figure 6, but may also be recovered using a conveyor 15 as shown in Figure 7, or a fiber drum, etc. By using a conveyor 15 or a fiber drum, the fibers 4 can be moved without restricting their position at the recovery location, allowing them to revolve or rotate freely without constraining their position, thereby enhancing the stretching effect.

[0074] In the method of recovery using the conveyor 15, as shown in Figure 12, by arranging rows of discharge holes that discharge fibers 4 with different rotation speeds in the direction of the conveyor travel, fibers 4 of different diameters can be continuously stacked. The number of these discharge hole rows is not limited to two; by increasing the number of discharge hole rows, multiple types of fibers 4 can be continuously stacked. Not limited to the direction of the conveyor travel, by arranging rows of discharge holes that discharge fibers 4 with different rotation speeds in the machine width direction, sheets 26 formed from fibers 4 of different diameters in the machine width direction can be continuously formed. Furthermore, not limited to each discharge hole row, the arrangement of fibers 4 of different diameters within the sheet 26 can be controlled by controlling the rotation speed of the fibers 4 in each discharge hole.

[0075] The present invention is highly versatile and can be applied to the manufacture of all known fibers. Therefore, it is not particularly limited by the polymer constituting the fiber. For example, examples of polymers constituting fiber 4 include polyester, polyamide, polyphenylene sulfide, polyolefin, polyethylene, polypropylene, and so on. Furthermore, the above polymer may contain additives such as titanium dioxide as a matting agent, silicon dioxide, kaolin, color inhibitors, stabilizers, antioxidants, deodorants, flame retardants, yarn friction reducers, coloring pigments, surface modifiers, and various functional particles and organic compounds, as long as they do not impair spinning stability, etc. Copolymerization may also be included.

[0076] The polymer constituting fiber 4 may consist of a single component or multiple components. In the case of multiple components, examples of configurations include core-sheath and side-by-side structures.

[0077] The cross-sectional shape of the fiber 4 forming the fiber 4 may be a round, triangular, flat, polygonal, star-shaped, or other irregular shape, or it may be hollow. In this case, the surface area per unit volume increases when the cross-sectional shape differs from a perfect circle, making it easier to receive forces from the swirling flow 12 and the rotating roll 13, increasing the rotational speed and allowing for the production of thinner fibers 4. Therefore, a cross-sectional shape that is flattened from a perfect circle is preferred, and a cross-sectional shape with irregularities on the surface is more preferred.

[0078] Furthermore, while the present invention aims to produce a fine-diameter fiber 4, the fineness of the single filament is not particularly limited. [Examples]

[0079] The present invention will be described in more detail below with reference to examples. The methods for measuring characteristic values ​​in the examples are as follows.

[0080] (1) Average fiber diameter (μm) Spun fibers were collected from each ejection hole, and 20 samples were randomly selected from the collected threads. Surface photographs were taken at 1000x magnification using a microscope. The width of the fibers was measured from the sample photographs, and the average of these measurements was taken as the average fiber diameter (diameter) for each ejection hole.

[0081] (2) Orbital velocity of the fiber (revolutions / second) The fibers immediately after being ejected from the ejection holes were photographed for 0.1 seconds using a high-speed camera. The number of times each ejected fiber revolved around the ejection hole was counted to measure the number of fiber revolutions per second, which was then determined as the fiber's revolution velocity.

[0082] (3) Rotation speed of the fiber (times / second) Figure 28 shows a schematic diagram of the method for measuring the rotation speed of a fiber. A single 32dtex PET fiber 4 for measurement was passed through each discharge hole 2 and fixed from the top of the nozzle 1. A mark 21 was placed on the surface of the fiber at a distance of 10 mm from the discharge hole 2 using black ink. A high-speed camera 18 was set up to image the fiber, and the behavior of the fiber at the position marked with point 21 was observed for 0.1 seconds. By counting the number of rotations of the fiber 4 from the movement of point 21 in the recorded video, the number of rotations of the fiber 4 per second was calculated and determined as the rotation speed of the fiber 4. Note that the viscosity of the fiber 4 is not taken into consideration in this measurement method.

[0083] [Examples 1-4, Comparative Examples 1-3] The fibers were spun using the fiber manufacturing apparatus shown in Figures 8-11. In each fiber manufacturing apparatus, the die 1 has two or six discharge holes 2 with a diameter of 0.25 mm, and air is injected from a single airflow nozzle 5 with a diameter of 2 mm into each polymer discharged from each discharge hole.

[0084] In each example and comparative example, the raw material resin was as follows, in accordance with ASTM-D1238: with a weight of 2.16 kg, a melt flow rate of 1100 g / 10 min at 230°C, and a density of 0.9 g / cm³. 3Polypropylene resin with a melting point of 180°C was used. Polymer at a molten resin temperature of 280°C was discharged from discharge port 2 at a single-hole discharge rate of 2g / min, and hot air at 280°C was sprayed from each airflow nozzle 5 to produce fibers under the conditions shown in Table 1. The test results are shown in Table 1.

[0085] [Example 1] The effect of varying the rotational speed of the fibers' orbit was evaluated. Fibers 4 were spun using the fiber manufacturing apparatus shown in Figure 8. The die 1 has six discharge holes 2. Three airflow nozzles were set as one unit, and a flow rate adjustment valve (flow rate control means) 23 was installed for each set. The flow rate was adjusted with each valve, and air was injected from one airflow nozzle 5 in the circumferential direction of each discharge hole 2 into the space surrounded by the airflow closing member 6, stretching the fibers 4 while they orbited due to the swirling flow 12 from a position directly below the discharge hole 2. The stretched fibers 4 were wound up by a winding roller 14 for each discharge hole. The rotational speed of the orbiting fibers was adjusted by adjusting the opening of each valve and changing the airflow rate supplied to each set. The rotational speed of the orbiting fibers 4 discharged from each discharge hole was measured and found to be 1100 revolutions / second at the fastest and 1000 revolutions / second at the slowest. The average fiber diameter of the collected fibers 4 was 2.5 μm at the discharge hole where the fiber 4 with the fastest orbital speed was discharged (hereinafter referred to as the fastest discharge hole), and 2.8 μm at the discharge hole where the fiber 4 with the slowest orbital speed was discharged (hereinafter referred to as the slowest discharge hole).

[0086] [Example 2] The effect of increasing the difference in rotational speed of fiber orbit is evaluated. Fiber 4 was spun using the same fiber manufacturing apparatus as in Example 1. The opening of the valve on the side with the fastest hole was increased to increase the supplied air flow rate. Otherwise, fiber 4 was spun under the same conditions as in Example 1. The rotational speed of the fibers 4 extruded from each discharge hole 2 was measured and was found to be 3000 revolutions / second at the fastest and 1000 revolutions / second at the slowest. The average fiber diameter of the collected fibers 4 was 1.8 μm at the fastest hole and 2.8 μm at the slowest hole.

[0087] [Example 3] The effect of varying the rotational speed of the fibers is evaluated. Fibers were spun using the fiber manufacturing apparatus shown in Figure 9. The die 1 has two discharge holes 2. Air was injected from one airflow nozzle 5 into a space enclosed by an airflow closure member 6, and the fibers 4 were stretched by a parallel flow from a position directly below the discharge hole 2, while the fibers 4 were rotated by a rotating roller 13. The stretched fibers 4 were wound up by a winding roller 14 for each discharge hole 2. The rotational speed of the fibers 4 was adjusted by changing the rotational speed of each rotating roller 13. The rotational speed of the fibers 14 discharged from each discharge hole 2 was measured, and it ranged from a maximum of 1100 revolutions / second to a minimum of 1000 revolutions / second. The average fiber diameter of the collected fibers was 2.6 μm at the discharge pore where the fastest rotating fiber was discharged (hereinafter referred to as the fastest pore) and 2.9 μm at the discharge pore where the slowest rotating fiber was discharged (hereinafter referred to as the slowest pore).

[0088] [Example 4] The effect of increasing the difference in rotational speed of the fibers was evaluated. Fibers were spun using the same fiber manufacturing apparatus as in Example 3. The rotational speed of the rotating roller 13 that contacts the fiber 4 being extruded from the fastest hole was increased. Otherwise, the fibers 4 were spun under the same conditions as in Example 3. The rotational speed of the fibers 4 extruded from each extrusion hole 2 was measured and found to be 3000 revolutions / second at the fastest and 1000 revolutions / second at the slowest. The average fiber diameter of the collected fibers was 1.8 μm at the fastest hole and 2.8 μm at the slowest hole.

[0089] [Comparative Example 1] The effect of the case where the fibers neither revolve nor rotate was evaluated. Fibers were spun using the fiber manufacturing apparatus shown in Figure 10. The die 1 has six discharge holes 2. Air was injected from one airflow nozzle 5 into a space surrounded by an airflow closure member 6, and the fibers 4 were stretched by a parallel flow from a position directly below the discharge holes 2. The stretched fibers 4 were wound up by a winding roller 14 for each discharge hole 2. The fibers 4 discharged from each discharge hole 2 neither revolved nor rotated. The average fiber diameter of the collected fibers 4 was 4.5 μm for all fibers discharged from each discharge hole 2.

[0090] [Comparative Example 2] The effect of not having a difference in the rotational speed of the fiber's revolution was evaluated. Fibers were spun using the fiber manufacturing apparatus shown in Figure 11. The die 1 has six discharge holes 2. Six total airflow nozzles were treated as one set, and a flow rate adjustment valve (flow rate control means) 23 was installed for each set. Air was injected from one airflow nozzle 5 in the circumferential direction of each discharge hole 2 into the space surrounded by an airflow closing member 6, and the fiber 4 was stretched while revolving in a swirling flow 12 from a position directly below the discharge hole 2. The fiber 4 was wound up for each discharge hole 2 by a winding roller 14. The rotational speed of the fibers revolving from each discharge hole was measured and found to be 1000 revolutions / second for all fibers. The average fiber diameter of the collected fibers was 2.8 μm for all fibers discharged from each discharge hole 2.

[0091] [Comparative Example 3] The effect of not having a difference in the rotational speed of the fibers was evaluated. Fibers were spun using the fiber manufacturing apparatus shown in Figure 9. The die 1 has two discharge holes 2. Air was injected from one airflow nozzle 5 into a space surrounded by an airflow closure member 6, and the fibers 4 were stretched by a parallel flow from a position directly below the discharge hole 2, while the fibers 4 were rotated by a rotating roller 13. The stretched fibers 4 were wound up by a winding roller 14 for each discharge hole 2. The rotational speed of each rotating roller 13 was set to the same speed. The rotational speed of the fibers 4 discharged from each discharge hole 2 was measured and found to be 1000 times / second for all fibers. The average fiber diameter of the collected fibers was 2.8 μm for all fibers discharged from each discharge hole 2.

[0092] [Table 1]

[0093] In all of Examples 1-4, fibers were collected with a difference in average fiber diameter between the fastest-growing and slowest-growing pores. In Example 1, the diameter of the fibers was reduced by making them revolve, and by adjusting the air flow rate, it was possible to create differences in the revolving speed of the fibers at each discharge hole of the nozzle, thereby creating differences in the average fiber diameter of the fibers formed at each discharge hole. In Example 2, by increasing the difference in airflow compared to Example 1, it was possible to increase the difference in the orbital speed of the fibers at each discharge hole of the nozzle, and thus increase the difference in the average fiber diameter of the fibers formed at each discharge hole. In Example 3, the diameter of the fibers was reduced by rotating them, and by adjusting the rotation speed of the rotating roller, it was possible to create differences in the rotation speed of the fibers at each discharge hole of the die, thereby creating differences in the average fiber diameter of the fibers formed at each discharge hole. In Example 4, by increasing the difference in rotational speed of the rotating rollers compared to Example 3, it was possible to increase the difference in the rotational speed of the fibers at each discharge hole of the die, and thus increase the difference in the average fiber diameter of the fibers formed at each discharge hole.

[0094] In Comparative Example 1, since the fibers were neither revolving nor rotating due to stretching by parallel flow alone, it was not possible to reduce the diameter of the fibers, and therefore it was not possible to create a difference in the average fiber diameter of the fibers formed at each discharge hole of the die. In Comparative Example 2, while it was possible to reduce the diameter of the fibers by causing them to revolve using a swirling flow, the lack of difference in the rotational speed of the revolving fibers prevented any difference in the average fiber diameter of the fibers formed at each discharge hole of the die. In Comparative Example 3, while it was possible to reduce the diameter of the fibers by rotating them, the lack of difference in rotational speed meant that it was not possible to create a difference in the average fiber diameter of the fibers formed at each discharge hole of the die. [Industrial applicability]

[0095] The manufacturing method and apparatus of the present invention can be applied not only to filaments but also to the spinning of fibers for other uses, such as nonwoven fabrics. [Explanation of symbols]

[0096] 1. Nozzle 2 Discharge hole 3 polymer 4 Fibers 5 Airflow nozzle 6. Airflow closure member 7 space 8 walls 9 Upper opening 10 Lower opening 11 Jet flow 12 Swirling flow 13 Rotating Rollers 14 Winding roller 15 Conveyor 16 Stretching force 17 Torsional force 18 High-Speed ​​Cameras 21 points (rotation measurement points) 22 Molecular Chain 23 Flow rate control means 24 Airflow supply member 25 Air flow passage 26 seats 27 Centrifugal force 28 Center of rotation 29 Temperature control means

Claims

1. A method for producing fibers by stretching a fibrous polymer extruded from a nozzle having multiple extrusion holes, The fibrous polymer discharged from the discharge hole is stretched while revolving around a straight line extending from the discharge hole in the polymer discharge direction, In two or more of the discharge holes, the orbital speed of the fibrous polymer discharged from each of the discharge holes is made different. A method for manufacturing fibers.

2. A method for producing fibers by stretching a fibrous polymer extruded from a nozzle having multiple extrusion holes, The fibrous polymer discharged from the discharge hole is stretched while revolving around a straight line extending from the discharge hole in the polymer discharge direction, The nozzle has multiple rows of discharge holes, each row in which multiple discharge holes are arranged in a single line. In two or more rows of discharge holes, the orbital speed of the fibrous polymer discharged from the discharge holes within each row of discharge holes is differentiated between the rows of discharge holes. A method for manufacturing fibers.

3. A method for producing fibers according to claim 1 or 2, wherein the difference in orbital speed is 100 times / second or more.

4. A method for producing fibers by stretching a fibrous polymer extruded from a nozzle having multiple extrusion holes, The fibrous polymer discharged from the discharge hole is stretched while rotating by applying a torsional force that rotates it around a straight line extending from the discharge hole in the direction of polymer discharge. In two or more of the discharge holes, the rotation speed of the fibrous polymer discharged from each of the discharge holes is made different. A method for manufacturing fibers.

5. A method for producing fibers by stretching a fibrous polymer extruded from a nozzle having multiple extrusion holes, The fibrous polymer discharged from the discharge hole is stretched while rotating by applying a torsional force that rotates it around a straight line extending from the discharge hole in the direction of polymer discharge. The nozzle has multiple rows of discharge holes, each row in which multiple discharge holes are arranged in a single line. In two or more rows of discharge holes, the rotation speed of the fibrous polymer discharged from the discharge holes within each row of discharge holes is differentiated between the rows of discharge holes. A method for manufacturing fibers.

6. The method for producing fibers according to claim 4 or 5, wherein the difference in rotational speed is 100 times / second or more.

7. An apparatus for producing fibers by stretching a fibrous polymer, A nozzle having multiple discharge holes for dispensing fibrous polymer, The system comprises an airflow nozzle for injecting airflow, which is positioned around the fibrous polymer discharged from the discharge hole, By forming a swirling flow with the airflow ejected from the airflow nozzle, the fibrous polymer is made to revolve around a straight line extending from the discharge hole in the direction of polymer discharge. The device has a flow rate control means that can adjust the flow rate of the airflow ejected from each set of airflow nozzles, with all the airflow nozzles assigned to one of the discharge holes considered as one set. A textile manufacturing device.

8. An apparatus for producing fibers by stretching a fibrous polymer, A nozzle having multiple discharge holes for dispensing fibrous polymer, The system comprises an airflow nozzle for injecting airflow, which is positioned around the fibrous polymer discharged from the discharge hole, By forming a swirling flow with the airflow ejected from the airflow nozzle, the fibrous polymer is made to revolve around a straight line extending from the discharge hole in the direction of polymer discharge. The nozzle has multiple rows of discharge holes, each row in which multiple discharge holes are arranged in a single line. The device has a flow rate control means that can adjust the flow rate of the airflow ejected from each of the multiple discharge holes in a single row of discharge holes, treating all the airflow nozzles assigned to each of the multiple discharge holes as a set. A textile manufacturing device.

9. An apparatus for producing fibers by stretching a fibrous polymer, A nozzle having multiple discharge holes for dispensing fibrous polymer, The system comprises an airflow nozzle for injecting airflow, which is positioned around the fibrous polymer discharged from the discharge hole, By forming a swirling flow with the airflow ejected from the airflow nozzle, the fibrous polymer is subjected to a torsional force that causes it to rotate around a straight line extending from the discharge hole in the direction of polymer discharge, thereby causing it to rotate on its own axis. The device has a temperature control means that can adjust the temperature of the airflow ejected from each set of airflow nozzles, with all the airflow nozzles assigned to one of the discharge holes considered as one set. A textile manufacturing device.

10. An apparatus for producing fibers by stretching a fibrous polymer, A nozzle having multiple discharge holes for dispensing fibrous polymer, The system comprises an airflow nozzle for injecting airflow, which is positioned around the fibrous polymer discharged from the discharge hole, By forming a swirling flow with the airflow ejected from the airflow nozzle, the fibrous polymer is subjected to a torsional force that causes it to rotate around a straight line extending from the discharge hole in the direction of polymer discharge, thereby causing it to rotate on its own axis. The nozzle has multiple rows of discharge holes, each row in which multiple discharge holes are arranged in a single line. The device has a temperature control means that can adjust the temperature of the airflow ejected from each set of airflow nozzles, with each set consisting of all the airflow nozzles assigned to each of the multiple discharge holes in one row of discharge holes being considered as one set. A textile manufacturing device.

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