Fiber manufacturing apparatus, fiber manufacturing method, and fiber having an uneven surface.

Abstract

To provide a novel technology that can manufacture fibers with an uneven surface. [Solution] The present invention provides a fiber manufacturing apparatus and the like that comprises a rotating body having a lower tray portion and an upper lid portion that engages with the lower tray portion, a resin supply portion that supplies molten resin to the center of the rotating body from the direction of the rotation axis of the rotating body, and an air supply portion that supplies air toward the rotating body, wherein the rotating body has a discharge hole between the lower tray portion and the upper lid portion, and the rotating body is rotated to diffuse the supplied molten resin into the rotating body, and after the resin is released from the discharge hole, stretched and flown away, air is supplied toward the rotating body to produce fibers having irregularities on the surface.

Description

[Technical Field]

[0001] The present invention relates to a fiber manufacturing apparatus, a fiber manufacturing method, and a fiber having irregularities on a surface. More specifically, the present invention relates to a fiber manufacturing apparatus and a fiber manufacturing method for manufacturing a fiber having irregularities on a surface, and a fiber having irregularities on a surface. [Background Art]

[0002] Various technologies relating to fiber manufacturing apparatuses and fiber manufacturing methods have been proposed since it was announced that clothing materials, filter materials, and the like using fine fibers exhibit useful functions.

[0003] In recent years, technologies for improving texture such as glossiness by imparting irregularities to the surface of fine fibers have also been proposed. For example, Patent Document 1 discloses an ultrafine fiber having fine irregularities on the fiber surface, wherein the fine irregularities satisfy (1) the number of fine irregularities is 1 to 19 per 40 μm 2 , and (2) the size of the fine irregularities satisfies the requirement of an aspect ratio of 10 or less. Patent Document 1 also discloses that the ultrafine polyester fiber is an ultrafine polyester fiber containing inorganic fine particles and having fine irregularities on the fiber surface. Specifically, it is also disclosed that the ultrafine polyester fiber is manufactured by a technique in which inorganic fine particles are contained in an island component polymer of a sea-island composite fiber having an easily soluble polyester as a sea component and a poorly soluble polyester as an island component, and when the sea component polymer is dissolved and removed, the inorganic fine particles are detached from the fiber surface and the vicinity of the fiber surface to form fine irregularities on the fiber surface. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2016-172945 [Brief Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, the conventional technologies described above had problems with environmental impact, such as increased labor costs due to processes like polymer dissolution and removal, and the generation of alkaline aqueous wastewater during dissolution and removal.

[0006] Therefore, in view of these circumstances, the main objective of the present invention is to provide a novel technology that can manufacture fibers having an uneven surface. [Means for solving the problem]

[0007] As a result of diligent experimental research conducted by the inventors of this invention, they discovered that a novel technology can be provided for the production of fibers with uneven surfaces by utilizing wind in a fiber manufacturing apparatus and fiber manufacturing method, thus completing the present invention.

[0008] The present invention provides a fiber manufacturing apparatus that first includes a rotating body having a lower tray portion and an upper lid portion that engages with the lower tray portion, a resin supply unit that supplies molten resin to the center of the rotating body from the direction of the rotation axis of the rotating body, and an air supply unit that supplies air toward the rotating body, wherein the rotating body has a discharge hole between the lower tray portion and the upper lid portion, and the apparatus manufactures fibers having an uneven surface by rotating the rotating body, diffusing the supplied molten resin inside the rotating body, and then releasing, stretching and flying the resin from the discharge hole, and then supplying air toward the rotating body.

[0009] The present invention also provides a method for manufacturing fibers, comprising at least the following steps: a resin supply step of supplying molten resin to the center of a rotating body from the direction of the rotation axis of the rotating body, the rotating body comprising a lower tray portion and an upper lid portion that engages with the lower tray portion; a molten resin diffusion step of diffusing the supplied molten resin into the rotating body while rotating the rotating body; and a fiber manufacturing step of manufacturing fibers having an uneven surface by supplying air toward the rotating body after releasing, stretching, and flying the supplied molten resin from a discharge hole between the lower tray portion and the upper lid portion of the rotating body while rotating the rotating body. In the fiber manufacturing method according to the present invention, the MFR of the molten resin may be 5 g / 10 min or more and 80 g / 10 min or less. In the fiber manufacturing method according to the present invention, the temperature of the air supplied to the rotating body may be 20°C or more and 300°C or less. In the fiber manufacturing method according to the present invention, the amount of air supplied to the rotating body may be 600 L / min or more and 1000 L / min or less.

[0010] The present invention further provides fibers having an uneven surface that satisfy the following requirements (A) and (B). (A) Number of bumps and depressions: 1 to 70 per 100 μm (B) The size of the bumps and dips is between 1 and 5 in terms of aspect ratio. [Effects of the Invention]

[0011] According to the present invention, a novel technology is available that enables the production of fibers having an uneven surface. The effects described herein are not necessarily limited to those described herein and may include any of the effects described herein. [Brief explanation of the drawing]

[0012] [Figure 1] This figure schematically shows an example of an embodiment of the fiber manufacturing apparatus 1 according to the present invention. [Figure 2] This figure schematically shows a front view of an example embodiment of the rotating body 11. [Figure 3] This figure schematically shows a plan view of the rotating body 11 of the embodiment shown in Figure 2. [Figure 4] This figure schematically shows a cross-sectional view of the rotating body 11 of the embodiment shown in Figure 2. [Figure 5] This is a photograph showing an example of fibers obtained using the fiber manufacturing apparatus 1 and fiber manufacturing method according to the present invention. [Figure 6] This is a photograph showing an example of a fiber with no surface irregularities. [Modes for carrying out the invention]

[0013] Hereinafter, preferred embodiments for carrying out the present invention will be described in detail with reference to the drawings. It should be noted that the embodiment described below shows an example of a typical embodiment of the present invention, and the scope of the present invention shall not be interpreted narrowly thereby.

[0014] 1. Fiber manufacturing apparatus 1 In FIG. 1, an example of an embodiment of the fiber manufacturing apparatus 1 according to the present invention is schematically illustrated. The fiber manufacturing apparatus 1 according to the present invention includes at least a rotating body 11, a resin supply unit 12, and an air supply unit 15. Further, if necessary, the apparatus may include a raw material supply unit 13, a diffusion prevention wall 14, and the like.

[0015] As described above, in the prior art, there have been problems with respect to environmental load, such as an increase in man-hours in steps such as polymer dissolution and removal, which raises concerns about cost increase, and the generation of waste alkaline aqueous solution from the dissolution and removal process. On the other hand, by using the present invention, fibers having irregularities can be easily manufactured without using inorganic fine particles or the like and without requiring a dissolution and removal step.

[0016] The fiber manufacturing apparatus 1 according to the present invention is mainly used for the purpose of manufacturing fine fibers having irregularities on the surface. Here, the term "fine fibers" refers to fibers including nanofibers having a fiber diameter of 700 nm or more and 10000 nm or less. The term "nanofibers" refers to fibers having a fiber diameter of less than 1000 nm. In the present invention, the cross-section of the fiber may be substantially circular or non-substantially circular. In the case of a non-substantially circular cross-section, the fiber diameter is the maximum dimension of the cross-section of the fiber.

[0017] Hereinafter, each part of the fiber manufacturing apparatus 1 according to the present invention will be described in detail.

[0018] (1) Rotating body 11 Figure 2 schematically shows a front view of an example embodiment of the rotating body 11, Figure 3 schematically shows a plan view of the rotating body 11 of the embodiment shown in Figure 2, and Figure 4 schematically shows a cross-sectional view of the rotating body 11 of the embodiment shown in Figure 2.

[0019] The rotating body 11 comprises a lower tray portion 111 and an upper cover portion 112 that engages with the lower tray portion 111. The rotating body 11 also has a discharge hole 110 between the lower tray portion 111 and the upper cover portion 112. In the fiber manufacturing apparatus 1 according to the present invention, the rotating body 11 is rotated to diffuse the supplied molten resin into the rotating body 11, and after it is released, stretched, and ejected from the discharge hole 110, air is supplied toward the rotating body 11 to manufacture fibers having an uneven surface (particularly fine fibers having an uneven surface).

[0020] The rotating body 11 can be rotated by a drive source 114 (for example, a motor). Furthermore, fibers with uneven surfaces formed by flight from the rotating body 11 are collected using a fiber collection device or the like. The shape of the rotating body 11 can be a combination of a roughly frustoconical shape and a roughly cylindrical shape, as shown in Figures 2 and 4. However, the present invention is not limited to this shape, as long as the supplied molten resin can be uniformly diffused within the rotating body 11 as it rotates. Moreover, it is preferable that the rotating body 11 is configured so that its rotation speed can be controlled.

[0021] The lower limit of the rotational speed of the rotating body 11 is, for example, 800 rpm or more, preferably 1000 rpm or more, more preferably 1500 rpm or more, even more preferably 2000 rpm or more, even more preferably 2200 rpm or more, or 2500 rpm or more. The upper limit of the rotational speed of the rotating body 11 is, for example, 4500 rpm or less, preferably 4000 rpm or less, and more preferably 3500 rpm or less. If the rotational speed is less than 800 rpm, there is insufficient centrifugal force and no pulling action is performed, so the molten resin may accumulate on the rotating body 11 and the molten resin may not fibrousize. Also, if the rotational speed exceeds 4500 rpm, the molten resin may fly off as droplets rather than fibers, and the molten resin may disperse before it can fibrousize.

[0022] The rotating body 11 is provided with a discharge hole 110 between the lower pan portion 111 and the upper lid portion 112. The discharge hole 110 can be, for example, a slit or punched shape (for example, a roughly circular shape, a roughly elliptical shape, a roughly square shape, a roughly rectangular shape, a hexagonal hole, a slit hole, etc.) provided between the lower pan portion 111 and the upper lid portion 112. If the discharge hole 110 is too large, the discharge pressure will be low, resulting in unevenness in fineness and fiber shape. Conversely, if the discharge hole 110 is too small, the discharge resistance will be strong, and the fibers will not be discharged. The material of the discharge hole 110 is not particularly limited as long as it has high thermal conductivity and allows the temperature of the entire rotating body 11 to be uniform. Examples include silver, copper, aluminum, zinc, iron, copper alloys, aluminum alloys, silicon-aluminum alloys, etc.

[0023] Preferably, the lower pan portion 111 comprises a pan portion 1111 and an engaging portion (not shown), and the upper lid portion 112 comprises a lid portion 1121 and an engaging portion (not shown) that engages with the engaging portion. The shapes of the engaging portion and the engaging portion are not particularly limited as long as the lower pan portion 111 and the upper lid portion 112 can engage with each other, but it is preferable that the shapes are such that the engaged state of the two can be maintained even when centrifugal force is applied due to rotation.

[0024] Furthermore, it is preferable that the upper lid portion 112 is equipped with a supply portion 1122 for supplying molten resin to the center of the rotating body 11. The shape of the supply portion 1122 can be, for example, a substantially frustoconical shape as shown in Figures 2 and 4, but is not limited to this in the present invention as long as it can supply molten resin to the center of the rotating body 11. In addition, in the present invention, the position in which the supply portion 1122 is formed is not particularly limited as long as it can supply molten resin to the center of the rotating body 11, and may be formed, for example, on the lower pan portion 111 side.

[0025] Furthermore, the shapes of the dish portion 1111 and the lid portion 1121 are preferably such that centrifugal force is applied uniformly during rotation, and are particularly preferably approximately circular in shape.

[0026] In the present invention, rotating blades (not shown) may be provided on a part of the rotating body 11 (for example, the side surface of the rotating body 11). By providing rotating blades on the rotating body 11, an airflow in a desired direction can be formed around the rotating body 11, and the molten resin that separates, expands, and flies from the discharge hole 110 of the rotating body 11 can be collected without being diffused into the surroundings. Preferably, multiple rotating blades (for example, 3 to 8) are arranged concentrically around the rotating body 11 at equal intervals (for example, 45° intervals).

[0027] Furthermore, the material of the rotating blades is not particularly limited as long as it can withstand the temperature during rotation of the rotating body 11, and examples include silver, copper, aluminum, zinc, iron, copper alloy, aluminum alloy, silicon-aluminum alloy, etc. The shape of the rotating blades is also not particularly limited as long as it can generate airflow in one axial direction, and examples include mixed-flow fans, propeller fans, turbo fans, axial-flow fans, etc.

[0028] In the present invention, a rotating body heating mechanism (not shown) for heating the rotating body 11 may be provided. By providing a rotating body heating mechanism, the molten resin diffusing from the center of the rotating body 11 can be heated. The rotating body heating mechanism may be a sheath heater that heats the rotating body 11 itself, or it may be a non-contact heating device such as an infrared heater or an electromagnetic induction heater that heats the rotating body 11.

[0029] The heating temperature of the rotating body 11 is not particularly limited as long as it can melt the thermoplastic resin, but it is preferably set to a temperature of 200°C or more and 400°C or less, and is above the melting temperature of the thermoplastic resin used.

[0030] Furthermore, it is preferable to provide a temperature detection means such as a thermopile or an infrared thermoviewer in the rotating body heating mechanism. By providing a temperature detection means, the temperature of the rotating body 11, preferably the temperature of the molten resin diffusing from the center of the rotating body 11, can be measured, and the amount of current supplied to the sheath heater, infrared heater, electromagnetic induction heater, etc., based on the temperature data, can be automatically controlled to control the temperature of the molten resin to a desired temperature.

[0031] Various thermoplastic resins can be used in the fiber manufacturing apparatus 1 according to the present invention. Specifically, examples include polypropylene (PP; including homopolymers, random copolymers, and block copolymers), polyethylene (PE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide (PA), polylactic acid (PLLA), polyglycolic acid (PGA), polyphenylene sulfide (PPS), polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin polymer (COP), cycloolefin copolymer (COC), and the like. In the present invention, one or more of these may be used in combination.

[0032] Furthermore, the present invention may also utilize biodegradable thermoplastic resins. Specifically, examples include polylactic acid (PLA), polyglycolic acid (PGA), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), polybutylene adipate / terephthalate (PBAT), polyethylene terephthalate succinate (PETS), polybutylene succinate adipate (PBSA), polybutylene succinate (PBS), poly(ε-caprolactone) (PCL), polyamide 4 (PA4), and poly(3-hydroxybutanoic acid) (P-(3HB)-). In addition, the present invention may use one or more of these in combination.

[0033] Furthermore, the thermoplastic resin described above may contain, as necessary, one or more additives in combination to obtain the desired physical properties. Specifically, for example, stabilizers such as UV absorbers, antioxidants, and heat stabilizers, pigments, dyes, lubricants, flame retardants, mold release agents, and sliding properties modifiers may be added. In addition, biodegradable modifiers may be added to further enhance biodegradability.

[0034] In the present invention, among these, it is preferable to use a resin as the molten resin whose melt flow rate (MFR; in the case of polypropylene, measured at 230°C and 2.16 kgf) is 5 g / 10 min or more and 80 g / 10 min or less, indicated by the extrusion temperature set in accordance with JIS K7210:2014 (ISO1133:2011), more preferably 15 g / 10 min or more and 70 g / 10 min or less, and even more preferably 20 g / 10 min or more and 60 g / 10 min or less. If the MFR is less than 5 g / 10 min, the fluidity of the molten resin is low, and it may be difficult to form fibers. Also, if the MFR is greater than 80 g / 10 min, the resin may fly as droplets when centrifuged, making it difficult to form fibers. In the present invention, among these, polypropylene is particularly preferred as the molten resin.

[0035] Furthermore, in the present invention, it is preferable that a baffle plate portion 113 is provided on the outer circumference of the lower pan portion 111 of the rotating body 11, extending from the lower pan portion 111. By providing the baffle plate portion 113 on the outer circle of the lower pan portion 111 of the rotating body 11, the molten resin is uniformly dispersed and flies between the discharge hole 110 and the baffle plate portion 113, thereby reducing fineness variations. The baffle plate portion 113 is not particularly limited, but for example, it can be a flange-like flange around the discharge hole 110 of the rotating body 11.

[0036] The baffle plate portion 113 is preferably 0.5 mm to 15 mm in length, more preferably 3 mm to 7 mm, even more preferably 4 mm to 6 mm, and particularly preferably 5 mm in length. Furthermore, the baffle plate portion 113 is preferably bent at an angle of 30° to 70° in the direction of the upper cover portion 112, and particularly preferably bent at an angle of 45°.

[0037] Furthermore, it is preferable that the baffle plate portion 113 is provided continuously around the outer circumference of the lower tray portion 112. In the present invention, it is also possible not to provide the baffle plate portion 113 continuously around the outer circumference of the lower tray portion 112, but in this case, the fiber mottling of fibers flying from the non-continuous areas becomes larger.

[0038] (2) Resin supply unit 12 The resin supply unit 12 supplies the molten resin to the center of the rotating body 11 from the direction of the rotation axis of the rotating body 11. The means for supplying the molten resin to the center of the rotating body 11 is not particularly limited in this invention, as long as it is capable of supplying a fixed amount of molten resin, such as an extruder. By supplying a fixed amount of molten resin, the discharge amount is stabilized, making it easier to produce fibers with a uniform fiber diameter. The type of screw of the extruder (e.g., screw diameter), screw rotation speed, discharge speed, etc., can be appropriately selected according to the purpose. In this specification, "center of the rotating body 11" refers to a pseudo-circle consisting of half the radius of the rotating body 11.

[0039] In Figure 1, the molten resin is supplied to the center of the rotating body 11 from above, but the present invention is not limited to this. That is, as long as the molten resin can be supplied to the center of the rotating body 11, the molten resin may be supplied to the rotating body 11 from below, the side, or the like.

[0040] (3) Raw material supply section 13 The fiber manufacturing apparatus 1 according to the present invention may include a raw material supply unit 13. The raw material supply unit 13 feeds thermoplastic resin into an extruder equipped with a screw, etc. The extruder may be used alone or as a tandem extruder. The fed thermoplastic resin is heated and kneaded by the screw of the extruder under heating conditions, and an extrusion force is applied toward the tip of the screw. The kneading conditions here vary depending on the thermoplastic resin used, but the heating conditions are preferably set to, for example, 200°C to 400°C, which is above the melting temperature of the thermoplastic resin. The screw rotation speed, discharge speed, etc., can be appropriately selected according to the purpose, although this also varies depending on the type of screw (for example, screw diameter, etc.).

[0041] (4) Diffusion prevention wall 14 The fiber manufacturing apparatus 1 according to the present invention may be equipped with a diffusion prevention wall 14. The diffusion prevention wall 14 can suppress the scattering of airborne fibers. The shape of the diffusion prevention wall 14 is not particularly limited as long as it can suppress the scattering of airborne fibers. In addition, although the diffusion prevention wall 14 is not depicted as having holes, windows, etc. in the fiber manufacturing apparatus 1 shown in Figure 1, in the present invention, the diffusion prevention wall 14 may have holes, windows, etc. in part. Furthermore, part or all of the diffusion prevention wall 14 may be made of acrylic, glass, etc., so that the inside can be observed.

[0042] (5) Air supply unit 15 The air supply unit 15 supplies air to the rotating body 11. By providing the air supply unit 15, air can be supplied to the rotating body 11 for fibers that have been released, stretched, and flown from the discharge holes 110 of the rotating body 11, thereby enabling the production of fibers with uneven surfaces. Specifically, the air supply unit 15 can be, for example, a blower (e.g., a propeller fan, a sirocco fan, etc.), an industrial blower, an air blower (e.g., a high-pressure blower, etc.), or a combination thereof, but is not limited to these in the present invention. Furthermore, the air supply unit 15 can be driven by a drive source (e.g., a motor, etc.).

[0043] In the air supply unit 15, the method of supplying air may be to supply compressed air from, for example, a blower, industrial blower, air blower, or a combination thereof, and adjust the supply amount via an adjustment valve. In addition, to prevent the ingress of foreign matter, a filter or the like may be added between the air supply source and the supply port.

[0044] In the present invention, it is preferable that the air supply unit 15 is provided with a mechanism that can adjust the air temperature and / or airflow rate. Specific examples of mechanisms that can adjust the air temperature include, but are not limited to, various heaters, heat exchangers, air coolers, and combinations thereof. Specific examples of mechanisms that can adjust the airflow rate include, but are not limited to, mechanisms that control the rotational speed of a blower (e.g., inverters, variable speed motors, etc.), mechanisms that adjust dampers and airflow paths (e.g., manual dampers, automatic dampers, etc.), mechanisms that adjust the angle of fan blades (e.g., variable pitch propellers, vane-type airflow control, etc.), and combinations thereof.

[0045] The temperature of the air supplied to the rotating body 11 is preferably between 20°C and 300°C, and more preferably between 30°C and 250°C. If the air temperature is below 20°C, the rotating kiln may cool too much due to the airflow, causing the molten resin to harden and making it difficult to discharge from the discharge port 110. If the air temperature exceeds 300°C, the molten resin may deteriorate, making fiber formation unstable.

[0046] The airflow supplied to the rotating body 11 is preferably 600 L / min or more and 1000 L / min or less, and more preferably 650 L / min or more and 900 L / min or less. If the airflow is less than 600 L / min, the airflow is insufficient, and the discharged fibers may not develop an uneven surface. If the airflow exceeds 1000 L / min, the airflow is too high, and the fiber formation process may become unstable.

[0047] As shown in Figure 1, it is preferable that the air supply unit 15 is designed to blow air in a substantially vertical direction when the rotation surface of the rotating body 11 is substantially horizontal. This makes it possible to efficiently create irregularities on fine fibers.

[0048] 2. Fiber manufacturing method The fiber manufacturing method according to the present invention includes at least a resin supply step, a molten resin diffusion step, and a fiber manufacturing step. It may also include, if necessary, a raw material supply step or the like.

[0049] The following describes in detail each step of the fiber manufacturing method according to the present invention.

[0050] (1) Resin supply process In the resin supply process, molten resin P is supplied to the center of a rotating body 11 from the direction of the rotation axis of the rotating body 11, which has a lower tray portion 111 and an upper lid portion 112 that engages with the lower tray portion 111. Note that the rotating body 11 is the same as the one described in "1. Fiber Manufacturing Apparatus 1", so its description is omitted here.

[0051] The method for supplying molten resin P to the center of the rotating body 11 from the direction of the rotation axis of the rotating body 11 can include, for example, supplying molten resin P using the resin supply unit 12 described above, but is not particularly limited in the present invention as long as it is capable of supplying molten resin P in a fixed quantity, such as an extruder. The type of screw of the extruder (e.g., screw diameter), screw rotation speed, discharge speed, etc. can be appropriately selected according to the purpose.

[0052] (2) Molten resin diffusion process In the molten resin diffusion process, the supplied molten resin P is diffused into the rotating body 11 while the rotating body 11 is rotated. Specifically, the supplied molten resin P can be diffused into the rotating body 11 by the centrifugal force caused by the rotation of the rotating body 11.

[0053] In this case, the rotating body heating mechanism that heats the rotating body 11 described above may also be operated to heat the molten resin P diffusing from the center of the rotating body 11. Alternatively, the temperature detection means described above may be used to measure the temperature of the rotating body 11, preferably the temperature of the molten resin P diffusing from the center of the rotating body 11, and the amount of current supplied to the rotating body heating mechanism may be automatically controlled based on the temperature data to control the temperature of the molten resin P to a desired temperature.

[0054] (3) Fiber manufacturing process While the rotating body 11 is being rotated, the molten resin P supplied from the discharge hole 110 between the lower tray portion 111 and the upper lid portion 112 of the rotating body 11 is released, stretched, and ejected, and then air is supplied towards the rotating body 11 to produce fibers having an uneven surface.

[0055] If the amount of resin is m, the angular velocity of the rotating body 11 is w, and the radius of the rotating body 11 is r, then the centrifugal force generated by the rotation of the rotating body 11 is given by f = mrw 2This is how it works. With this centrifugal force f, the molten resin P is discharged from the discharge hole 110. In the state before the fibers are drawn down, only the amount of molten resin P changes, so the fibers accumulate at the edge of the rotating body 11 until the fibers are drawn down. Immediately after the fibers are drawn down, the specific surface area increases, and the cooling intensifies. Then, in the state after the fibers are drawn down, fiber formation occurs while maintaining a good balance between the centrifugal force f and the cooling.

[0056] In this process, air is supplied to the fibrous molten resin P from the air supply unit 15 to produce fibers with an uneven surface. The air supply unit 15 is the same as the one described in "1. Fiber Manufacturing Apparatus 1," so its description is omitted here.

[0057] (4) Raw material supply process The fiber manufacturing method according to the present invention may include a raw material supply step. In the raw material supply step, a thermoplastic resin is fed into an extruder equipped with a screw or the like. The fed thermoplastic resin is heated and kneaded by the screw of the extruder under heating conditions, and an extrusion force is applied toward the tip of the screw. In the raw material supply step, the kneading conditions (e.g., heating conditions), the type of screw (e.g., screw diameter), the screw rotation speed, the discharge speed, etc., can be appropriately selected according to the purpose.

[0058] 3. Fibers with an uneven surface The fiber having surface irregularities according to the present invention satisfies the following conditions (A) and (B). (A) Number of bumps and depressions: 1 to 70 per 100 μm (B) The size of the bumps and dips is between 1 and 5 in terms of aspect ratio.

[0059] The fine fibers produced by the fiber manufacturing apparatus 1 and fiber manufacturing method according to the present invention can be used in a variety of applications, taking advantage of their characteristics such as strength, flexibility, and breathability. For example, medical applications such as filter materials and medical fibers (e.g., bandages, dressings, etc.); industrial applications such as high-performance filters, sound-absorbing materials, heat-insulating materials, and reinforcing fibers for composite materials; textile applications such as high-performance fibers (e.g., outdoor wear, sportswear, etc.), water-repellent fiber products, and breathable fiber products; environmental applications such as biodegradable materials and soil conditioners; and electronic device applications such as conductive fibers and sensor materials. However, the present invention is not limited to these.

[0060] Furthermore, the fibers having surface irregularities according to the present invention have a moderate luster and can be used for purposes such as improving texture and color tone. Moreover, since the fibers having surface irregularities according to the present invention have a larger specific surface area compared to fibers without surface irregularities, improvements in hygroscopicity, water absorption, adsorption, dyeability and processability, heat retention, and frictional resistance can be expected. Therefore, they are particularly suitable for use in medical applications, textile applications, and the like.

[0061] Here, "concave and concave" refers to convex portions; fine protrusions formed on the fiber surface, and concave portions; areas where no such protrusions are formed. Therefore, protruding portions refer to convex portions observed on the fiber surface with an electron scanning microscope, whose size is 5 or less in aspect ratio.

[0062] Furthermore, the fiber having surface irregularities according to the present invention has (A) the number of irregularities being 1 to 70 per 100 μm, preferably 1 to 50 per 100 μm. If the number of irregularities is less than 1 per 100 μm, an increase in specific surface area cannot be expected, and the effect of the irregular fiber is difficult to obtain. Also, if the number of irregularities is more than 70 per 100 μm, a decrease in physical properties such as the strength and elongation characteristics of the fiber occurs, which is undesirable.

[0063] Furthermore, the fiber having surface irregularities according to the present invention has (B) an aspect ratio of 1 or more and 5 or less. Here, in this specification, "aspect ratio" is defined as the ratio of length (C = L / W) to width (W) in a shape, where length (L) is in the direction parallel to the fiber axis and width (W) is in the direction perpendicular to it. If the size of the irregularities is less than an aspect ratio of 1, it is undesirable because it causes a decrease in physical properties such as the strength and elongation characteristics of the fiber. If the size of the irregularities is greater than an aspect ratio of 5, an increase in specific surface area cannot be expected, and it is difficult to obtain the effect of an irregular fiber.

[0064] Furthermore, the following configurations can also be adopted in the present invention. [1] A rotating body comprising a lower tray portion and an upper lid portion that engages with the lower tray portion, A resin supply unit that supplies molten resin to the center of the rotating body from the direction of the rotation axis of the rotating body, An air supply unit that supplies air towards the rotating body, Having at least, The rotating body has a discharge hole between the lower plate portion and the upper lid portion. A fiber manufacturing apparatus that produces fibers having an uneven surface by rotating the rotating body, diffusing the supplied molten resin into the rotating body, and then releasing, stretching, and flying the resin from the discharge hole, and then supplying air toward the rotating body. [2] The fiber manufacturing apparatus according to [1], wherein the MFR of the molten resin is 5 g / 10 min or more and 80 g / 10 min or less. [3] The fiber manufacturing apparatus according to [1] or [2], wherein the temperature of the air supplied toward the rotating body is 20°C or more and 300°C or less. [4] A fiber manufacturing apparatus according to any one of [1] to [3], wherein the airflow rate supplied to the rotating body is 600 L / min or more and 1000 L / min or less. [5] A resin supply step involves supplying molten resin to the center of a rotating body from the direction of the rotation axis of the rotating body, to a rotating body comprising a lower tray portion and an upper lid portion that engages with the lower tray portion. A molten resin diffusion step in which the supplied molten resin is diffused into the rotating body while the rotating body is rotated, A fiber manufacturing process for producing fibers having irregularities on their surface by rotating the rotating body, releasing, stretching, and flying the supplied molten resin from the discharge hole between the lower tray portion and the upper lid portion of the rotating body, and then supplying air toward the rotating body; A method for manufacturing fibers, comprising at least [a certain element]. [6] The fiber manufacturing method according to [5], wherein the MFR of the molten resin is 5 g / 10 min or more and 80 g / 10 min or less. [7] The fiber manufacturing method according to [5] or [6], wherein the temperature of the air supplied to the rotating body is 20°C or more and 300°C or less. [8] The fiber manufacturing method according to any one of [5] to [7], wherein the amount of air supplied to the rotating body is 600 L / min or more and 1000 L / min or less. [9] A fiber having an uneven surface that satisfies the following requirements (A) and (B). (A) Number of bumps and depressions: 1 to 70 per 100 μm (B) The size of the bumps and dips is between 1 and 5 in terms of aspect ratio. [Examples]

[0065] The present invention will be described in more detail below based on examples. The embodiments described below are merely examples of typical embodiments of the present invention, and this should not be interpreted as narrowing the scope of the present invention.

[0066] <Example 1> Using the fiber manufacturing apparatus and fiber manufacturing method according to the present invention described above, 7 g of molten resin of Y2000GV (prime polymer, homo PP, MFR: 18 g / 10 min) was supplied to the center of a rotating body heated to 230°C while supplying air at an air temperature of 30°C and an air volume of 664 L / min toward the center of the rotating body, and the body was rotated at 2000 rpm to obtain fibers. When the obtained fibers were observed with a SEM (SEM-EDS; manufactured by JEOL Ltd.; JCM-7000), it was confirmed that irregularities were formed on the surface of the fibers, with the number of irregularities being 3 to 10 per 100 μm and the aspect ratio being 1 to 3.

[0067] <Example 2> Fibers were obtained using the same method as described in Example 1, except that the temperature of the supplied air was set to 150°C. When the obtained fibers were observed by SEM, it was confirmed that irregularities were formed on the surface of the fibers, with the number of irregularities ranging from 2 to 38 per 100 μm and the aspect ratio ranging from 1 to 3.

[0068] <Example 3> Compared to the method described in Example 1, fibers were obtained using the same method except that the temperature of the supplied air was set to 200°C. When the obtained fibers were observed by SEM, it was confirmed that irregularities were formed on the surface of the fibers, with the number of irregularities being 1 to 4 per 100 μm and the aspect ratio being 1 to 4. Figure 5 is a photograph showing the results of Example 3 as an example of fibers obtained using the fiber manufacturing apparatus and fiber manufacturing method according to the present invention. On the other hand, Figure 6 is a photograph showing an example of fibers in which no irregularities were formed on the surface, in contrast to Figure 5.

[0069] <Example 4> Fibers were obtained using the same method as described in Example 1, except that the temperature of the supplied air was set to 250°C. When the obtained fibers were observed by SEM, it was confirmed that irregularities were formed on the surface of the fibers, with the number of irregularities being 1 to 9 per 100 μm and the aspect ratio being 1 to 5.

[0070] <Example 5> Fibers were obtained using the same method as described in Example 1, except that the airflow rate supplied was set to 543 L / min. When the obtained fibers were observed by SEM, it was confirmed that irregularities were formed on the surface of the fibers, with the number of irregularities being 1 to 3 per 100 μm and the aspect ratio being 7 to 9. [Industrial applicability]

[0071] The present invention provides a novel technology that enables the production of fibers with uneven surfaces. Therefore, by taking advantage of their characteristics such as strength, flexibility, and breathability, they can be used in a variety of applications. For example, they are expected to be applied in a wide range of fields, including medical, industrial, textile, environmental, and electronic device applications. [Explanation of Symbols]

[0072] 1: Fiber manufacturing equipment 11: Solids of revolution 110:Discharge hole 111: Lower tray 1111:Dish section 112: Top lid 1121: Lid 1122: Supply section 113: Obstruction board section 114: Power source 12: Resin supply unit 13: Raw material supply department 14: Diffusion prevention wall 15: Air supply unit P: Molten resin

Claims

1. A rotating body comprising a lower tray portion and an upper lid portion that engages with the lower tray portion, A resin supply unit that supplies molten resin to the center of the rotating body from the direction of the rotation axis of the rotating body, An air supply unit that supplies air towards the rotating body, Having at least, The rotating body has a discharge hole between the lower plate portion and the upper lid portion. A fiber manufacturing apparatus that produces fibers having an uneven surface by rotating the rotating body, diffusing the supplied molten resin into the rotating body, and then releasing, stretching, and flying the resin from the discharge hole, and then supplying air toward the rotating body.

2. A resin supply step involves supplying molten resin to the center of a rotating body from the direction of the rotation axis of the rotating body, to a rotating body comprising a lower tray portion and an upper lid portion that engages with the lower tray portion. A molten resin diffusion step in which the supplied molten resin is diffused into the rotating body while the rotating body is rotated, A fiber manufacturing process for producing fibers having irregularities on their surface by rotating the rotating body, releasing, stretching, and flying the supplied molten resin from the discharge hole between the lower tray portion and the upper lid portion of the rotating body, and then supplying air toward the rotating body; A method for manufacturing fibers, comprising at least [a certain element].

3. The fiber manufacturing method according to claim 2, wherein the MFR of the molten resin is 5 g / 10 min or more and 80 g / 10 min or less.

4. The fiber manufacturing method according to claim 2, wherein the temperature of the air supplied toward the rotating body is 20°C or more and 300°C or less.

5. The fiber manufacturing method according to claim 2, wherein the amount of air supplied to the rotating body is 600 L / min or more and 1000 L / min or less.

6. A fiber having an uneven surface that satisfies the following requirements (A) and (B). (A) The number of bumps and depressions is between 1 and 70 per 100 μm. (B) The size of the bumps and dips is between 1 and 5 in terms of aspect ratio.

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