A device for producing a spliced melt-spun segmented fiber

Abstract

This invention provides an apparatus for preparing melt-spun bamboo-like fibers, comprising a feeding system, a coaxial spinneret assembly, an outer diameter stabilization and shaping unit, a periodic cooling and solidification unit, and a drawing and collecting unit. The feeding system is divided into a shell melt continuous supply unit and a filler melt supply unit, which are respectively connected to the inner core needle of the spinneret assembly and the shell annular flow channel. The rate is controlled by a synchronous control unit to form bamboo-like fibers, and the detection feedback is performed by an online detection unit. This invention can produce bamboo-like fibers with "uniform outer diameter and bamboo-like inner structure", avoiding the mechanical property degradation caused by abrupt changes in outer diameter and necking in fine details in traditional beaded fibers. By changing the filler, various special fibers can be produced. Slight bulging will not occur through the shell bypass pressure relief channel. By setting the core layer truncated structure, the boundary clarity of the internal filler segment is improved, so that the longitudinal section of the fiber presents a segmented morphology that is closer to bamboo.

Description

Technical Field

[0001] This invention relates to the fields of melt spinning, coaxial composite spinning and functional fiber forming technology, specifically to a composite fiber preparation device and method with uniform outer diameter and segmented internal bamboo-like filling. Background Technology

[0002] Conventional fiber materials are mostly continuous cylindrical structures with a basically homogeneous axial diameter, and their composition and properties are generally relatively stable along the fiber length. With the development of functional textiles, biomimetic materials, composite reinforcing materials, flexible sensing materials, and medical functional materials, there is a growing desire for fibers to not only possess composite characteristics in their material composition but also to form designable axially segmented structures within the fiber. For example, conductive materials, phase change materials, reinforcing materials, adsorbent materials, magnetic materials, antibacterial materials, or drug-loaded materials can be periodically distributed along the fiber length, thereby achieving localized functional enhancement, segmented response, directional interlocking, gradient loading, or biomimetic structural effects.

[0003] Bamboo-like fibers are generally understood as fibers exhibiting periodic or quasi-periodic structural variations along their axial direction. Existing literature and processes describing bamboo-like fibers mostly focus on the alternating thick and thin sections of their external morphology, meaning the fiber appearance resembles bamboo segments with enlarged nodes and thinner connecting sections. While this external bamboo-like structure can improve surface roughness and mechanical interlocking, it also brings significant drawbacks: the finer details often become mechanically weaker areas, and stress concentration easily occurs at the transition points between nodes and finer details; during drawing, weaving, winding, and composite processing, abrupt changes in outer diameter can also lead to tension fluctuations, uneven friction, fiber breakage, and decreased processing stability. Therefore, for fiber materials requiring continuous processing performance, uniform stress resistance, and consistent appearance, an external bamboo-like morphology with alternating thick and thin sections is not always an ideal choice.

[0004] Currently, fiber preparation methods related to bamboo-like structures mainly include mechanical intermittent stretching, unstable jetting, solution electrospinning to form beaded structures, post-treatment shrinkage molding, and multi-component composite molding. While these methods can achieve some axial structural variation, the resulting fibers often exhibit random beaded structures or uneven external thicknesses, rather than a controllable structure with a uniform external diameter and segmented internal filling. In particular, beaded fibers formed during solution electrospinning or unstable jetting are often caused by jet instability, solvent evaporation, and imbalances in surface tension and viscoelasticity, resulting in significant randomness in bead size, bead spacing, connecting filament diameter, and transition morphology. This "partially coarse, partially fine" external structure significantly affects the uniformity of fiber stress, making the fiber more susceptible to stress concentration, fatigue damage, or breakage in the finer parts or bead transition areas, thereby weakening the fiber's tensile strength, elongation at break, long-term stability, and subsequent processing performance.

[0005] On the other hand, existing coaxial melt spinning processes allow the shell melt and core melt to enter the coaxial spinneret separately, and then combine at the spinneret orifice to form a core-shell structure fiber. This process has advantages such as being solvent-free, highly continuous, and suitable for thermoplastic polymer processing, making it an important method for preparing composite functional fibers. However, conventional coaxial melt spinning typically involves the continuous and stable simultaneous extrusion of the core and shell layers, resulting in a relatively uniform internal composition of the composite fiber in the axial direction, making it difficult to form an internally periodically segmented filling structure. Simply creating axial differences by periodically changing the core layer feed pressure or drafting speed can easily lead to problems such as outer diameter fluctuations, shell bulging, core layer eccentricity, core layer exposure, interface instability, or fiber breakage.

[0006] Therefore, it is necessary to propose a new apparatus and method for preparing composite fibers adapted to melt spinning. This method does not aim for significant alternations in fiber diameter on the surface, but rather maintains a basically uniform diameter on the fiber surface, while simultaneously forming periodic or quasi-periodic core segments, filler segments, or functional segments within the fiber. Through this "uniform outer diameter, bamboo-like inner structure" design, it is possible to maintain the fiber's mechanical continuity, appearance uniformity, and processing stability as much as possible, while achieving axial partitioning of functional materials within the fiber. This avoids the mechanical property degradation problems caused by abrupt changes in outer diameter and necking at finer points in traditional beaded fibers. Summary of the Invention

[0007] To address the aforementioned deficiencies in the prior art, this invention provides an apparatus for preparing melt-spun slub-like fibers, comprising a feeding system controlled by a synchronous control unit 8 and sequentially connected to a coaxial spinneret 4, an outer diameter stabilizing and shaping unit 5, a periodic cooling and solidification unit 6, and a drawing and collecting unit 7. The feeding system is divided into two parts: a shell melt continuous supply unit 1 and a filler melt supply unit 2, both connected to the coaxial spinneret 4. A core layer pulse supply unit 3 is also provided between the filler melt supply unit 2 and the coaxial spinneret 4. The synchronous control unit 8 controls the supply speed of the shell melt continuous supply unit 1 and the core layer pulse supply unit 3. The slub-like fibers are formed by the coaxial spinneret 4 and cooled by the periodic cooling and solidification unit 6 before being collected by the drawing and collecting unit 7. It also includes an online detection unit 9, which monitors the operating power of the shell melt continuous supply unit 1, the filler melt supply unit 2, the core layer pulse supply unit 3, the outer diameter stabilization and shaping unit 5, the periodic cooling and solidification unit 6, and the stretching and collecting unit 7, and feeds it back to the synchronous control unit 8 for regulation.

[0008] Furthermore, the continuous supply unit 1 for the shell melt includes a shell hopper 11, a shell heater 13, a shell melting chamber 12, a shell metering pump 14, and a shell pressure stabilizing chamber 16 connected in sequence. The shell hopper 11 receives external raw materials, heats them through the shell heater 13 to form a shell melt, and then transports them to the shell melting chamber 12. The shell melt in the shell melting chamber 12 is transported to the shell pressure stabilizing chamber 16 through the shell metering pump 14. The shell pressure stabilizing chamber 16 is connected to the coaxial spinneret assembly 4. A shell pressure sensor 15 is also installed between the shell metering pump 14 and the shell pressure stabilizing chamber 16 to monitor and detect the feeding pressure and flow stability of the shell melt. A shell bypass pressure relief channel 17 with a controllable back pressure valve is also provided in parallel with the shell pressure stabilizing chamber 16. One end of the shell bypass pressure relief channel 17 is connected to the pressure relief port of the shell metering pump 14, and the other end is connected to the coaxial spinneret assembly 4.

[0009] Furthermore, the filler melt supply unit 2 includes a core layer hopper 21, a core layer melting chamber 22, and a core layer buffer chamber 24. A core layer heater 23 is installed in the core layer buffer chamber 24. The core layer hopper 21 receives raw materials and transports them to the core layer melting chamber 22. After being heated by the core layer heater 23 to form a core layer melt, the melt flows into the core layer buffer chamber 24 and is then transported to the coaxial spinneret assembly 4 by the core layer pulse feeding unit 3. A core layer pressure sensor 25 is installed inside the core layer buffer cavity 24.

[0010] Furthermore, the core layer pulse feeding unit 3 is a high-temperature resistant servo plunger pulse pump 31, which includes a pulse valve 36, a servo driver 32, a reciprocating plunger 33 and a one-way valve group 34 connected in sequence. A heat insulation sleeve 35 is provided at the connection point, and a core layer cut-off structure 37 is also provided at one end of the pulse valve 36.

[0011] Furthermore, the coaxial spinneret 4 includes an outer spinneret 41 connected to the shell melt continuous supply unit 1 and an inner core needle 42 connected to the filler melt supply unit 2. The bottom of the outer spinneret 41 is provided with a spinneret hole 46, and the inner core needle 42 is located at the center of the outer spinneret 41. The inner wall of the outer spinneret 41 and the outer wall of the inner core needle 42 form a shell annular flow channel 43 with an anti-backflow structure 47. A core layer central flow channel 44 is provided at the center of the inner core needle 42. The outlet of the core layer central flow channel 44 merges with the shell annular flow channel 43 to form a composite confluence cavity 45 that connects to the spinneret hole 46.

[0012] Furthermore, the outer diameter stabilizing and shaping unit 5 includes a connected sizing sleeve 52 and a non-contact air-float sizing structure 54. The sizing sleeve 52 is provided with a micro-perforated sizing ring 53 with cooling holes inside, and the side wall of the sizing sleeve 52 is connected to an external cooling source. The non-contact air flotation sizing structure 54 includes a first sizing cooling zone 55 and a second uniform cooling zone 56, both of which are provided with cooling holes that connect to an external cooling source.

[0013] Furthermore, the periodic cooling and solidification unit 6 is provided with an annular cooling chamber 64, and a plurality of cooling nozzles 63 are arranged around the inner wall of the annular cooling chamber 64. The cooling nozzles 63 are connected to the cooling medium supply source 61 through a pulse cooling valve 62.

[0014] Furthermore, the drawing and collecting unit 7 includes a guide roller 71, a drawing roller 72, a tension controller 73, and a winding machine 74 arranged in sequence. After being combed by the guide roller 71, the fiber is transferred to the drawing roller 72 for drawing and sizing. After being regulated by the tension controller 73, it is collected by the winding machine 74.

[0015] Furthermore, the synchronization control unit 8 includes a controller 81, a human-machine interface 82, a temperature control module 83, a pressure acquisition module 84, a pump speed control module 85, a pulse parameter setting module 86, a phase compensation module 87, and a closed-loop feedback module 88.

[0016] Furthermore, the online detection unit 9 includes an outer diameter detection mechanism, a temperature detection mechanism, and an internal structure detection mechanism; Outer diameter measurement mechanisms include laser diameter gauges or cameras, which obtain the fiber outer diameter and its fluctuation in real time by measuring the fiber profile; The temperature detection mechanism includes an infrared temperature sensor, which detects the surface temperature of the fiber after it leaves the cooling zone. Internal structure inspection mechanisms include ultrasonic testing, resistance testing, capacitance testing, X-ray fluoroscopy, and near-infrared testing.

[0017] The beneficial effects of this invention are: 1. By controlling the supply speed of the shell melt continuous supply unit and the core pulse supply unit through the synchronous control unit, the coaxial spinneret assembly is used to form bamboo-like fibers with "equal outer diameter and bamboo-like inner structure". This can achieve axial partitioning of functional materials inside the fiber while maintaining the mechanical continuity, appearance uniformity and processing stability of the fiber as much as possible, avoiding the mechanical property degradation caused by abrupt changes in outer diameter and necking of fine details in traditional beaded fibers. 2. By changing the filler in the filler melt supply unit, a variety of different special fibers can be produced; 3. The flow rate of the core layer or filler material into the composite melt stream for a short time when the pulse is turned on is regulated by the shell bypass pressure relief channel 17 and the controllable back pressure valve, so as to prevent slight bulging of the fiber exterior due to the short-term increase in the total ejection volume. 4. By quickly closing or retracting the core layer material through the core layer severing structure, the core layer or filler material can be cut off in time at the end of the internal filler section, so as to reduce tailing, filament pulling and the connection between adjacent filler sections, improve the clarity of the boundary of the internal filler section, and make the segmented morphology of the fiber longitudinal section more like bamboo joint. At the same time, since the severing process occurs inside the continuous shell coating, no obvious cut marks or abrupt changes in outer diameter will be formed on the fiber surface. 5. The phase compensation module allows for secondary micro-adjustment of the sample after detection, reducing errors caused by flow hysteresis. 6. The online detection unit can simultaneously ensure the uniformity of the fiber's external diameter and the stability of its internal bamboo-like segmented structure during the production process, making it more suitable for continuous production. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the core layer pulse feeding unit structure of the present invention; Figure 3 This is a schematic diagram of the coaxial spinneret assembly structure of the present invention; Figure 4 This is a schematic diagram of the outer diameter stabilizing and shaping unit structure of the present invention; Figure 5 This is a schematic diagram of the periodic cooling and solidification unit structure of the present invention; Figure 6 This is a schematic diagram of the drawing and collecting unit structure of the present invention; Figure 7 This is a schematic diagram of the finished bamboo-like fiber structure in this invention; In the picture, 1. Shell melt continuous supply unit; 11. Shell hopper; 12. Shell melting chamber; 13. Shell heater; 14. Shell metering pump; 15. Shell pressure sensor; 16. Shell pressure stabilizing chamber; 17. Shell bypass pressure relief channel; 2. Filler melt supply unit; 21. Core layer hopper; 22. Core layer melting chamber; 23. Core layer heater; 24. Core layer buffer chamber; 25. Core layer pressure sensor; 3. Core layer pulse feeding unit; 31. Pulse pump; 32. Servo driver; 33. Reciprocating plunger; 34. One-way valve assembly; 35. Insulation jacket; 36. Pulse valve; 37. Core layer cutting structure; 4. Coaxial spinneret assembly; 41. Outer spinneret; 42. Inner core needle; 43. Shell annular flow channel; 44. Core center flow channel; 45. Composite manifold; 46. Spinneret orifice; 47. Anti-backflow structure; 5. Outer diameter stabilizing and shaping unit; 52. Sizing sleeve; 53. Microporous sizing ring; 54. Non-contact air flotation sizing structure; 55. First sizing cooling zone; 56. Second uniform cooling zone; 6. Periodic cooling and solidification unit; 61. Cooling medium supply source; 62. Pulse cooling valve; 63. Cooling nozzle; 64. Annular cooling chamber; 7. Drafting and collecting unit; 71. Guide roller; 72. Drafting roller; 73. Tension controller; 74. Winding machine; 8. Synchronous control unit; 81. Controller; 82. Human-machine interface; 83. Temperature control module; 84. Pressure acquisition module; 85. Pump speed control module; 86. Pulse parameter setting module; 87. Phase compensation module; 88. Closed-loop feedback module; 9. Online detection unit. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention and to make the above-mentioned features, objectives, and advantages of the present invention clearer and easier to understand, the present invention will be further described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0020] Example 1: As Figure 1-2 As shown, the present invention includes: a feeding system controlled by a synchronous control unit 8 and connected in sequence, a coaxial spinneret 4, an outer diameter stabilizing and shaping unit 5, a periodic cooling and solidification unit 6, and a drawing and collecting unit 7. The feeding system is divided into two parts: a shell melt continuous supply unit 1 and a filler melt supply unit 2, both of which are connected to the coaxial spinneret 4. A core layer pulse feeding unit 3 is also provided between the filler melt supply unit 2 and the coaxial spinneret 4. The synchronous control unit 8 controls the supply speed of the shell melt continuous supply unit 1 and the core layer pulse feeding unit 3. The fibers are integrated by the coaxial spinneret 4 to form bamboo-like fibers. After being cooled by the periodic cooling and solidification unit 6, they are collected by the drawing and collecting unit 7. It also includes an online detection unit 9, which monitors the operating power of the shell melt continuous supply unit 1, the filler melt supply unit 2, the core layer pulse supply unit 3, the outer diameter stabilization and shaping unit 5, the periodic cooling and solidification unit 6, and the stretching and collecting unit 7, and feeds it back to the synchronous control unit 8 for regulation.

[0021] refer to Figure 1The shell melt continuous supply unit 1 includes a shell hopper 11, a shell heater 13, a shell melting chamber 12, a shell metering pump 14, and a shell pressure stabilizing chamber 16 connected in sequence. The shell hopper 11 receives external raw materials, heats them through the shell heater 13 to form shell melt, and then transports them to the shell melting chamber 12. The shell melt in the shell melting chamber 12 is transported to the shell pressure stabilizing chamber 16 through the shell metering pump 14. The shell pressure stabilizing chamber 16 is connected to the coaxial spinneret assembly 4. The shell material enters the shell melting chamber 12 from the shell hopper 11, where it is melted and plasticized by the shell heater 13. It is then stably delivered by the shell metering pump 14 to the shell annular flow channel 43 of the coaxial spinneret assembly 4. The shell pressure stabilizing chamber 16 is used to reduce the pressure fluctuations caused by the core layer pulse feeding, so that the shell material can continuously and stably form the outer coating layer.

[0022] A shell pressure sensor 15 is also installed between the shell metering pump 14 and the shell pressure stabilizing chamber 16 to monitor and detect the feeding pressure and flow stability of the shell melt. refer to Figure 1 The filler melt supply unit 2 includes a core layer hopper 21, a core layer melting chamber 22, and a core layer buffer chamber 24. A core layer heater 23 is installed in the core layer buffer chamber 24. The core layer hopper 21 receives raw materials and transports them to the core layer melting chamber 22. After being heated by the core layer heater 23 to form a core layer melt, the melt flows into the core layer buffer chamber 24 and is then transported to the coaxial spinneret assembly 4 by the core layer pulse feeding unit 3. The core layer or filler material enters from the core layer hopper 21, is heated to a flowable state by the core layer heater 23 in the core layer melting chamber 22, and then enters the core layer buffer chamber 24. The core layer buffer chamber 24 is connected to the core layer pulse feeding unit 3 to provide a stable inlet pressure for intermittent feeding.

[0023] A core layer pressure sensor 25 is installed inside the core layer buffer cavity 24.

[0024] refer to Figure 2 The core layer pulse feeding unit 3 is a high-temperature resistant servo plunger pulse pump 31. The high-temperature resistant servo plunger pulse pump 31 includes a pulse valve 36, a servo driver 32, a reciprocating plunger 33, and a one-way valve group 34 connected in sequence, with an insulation sleeve 35 at the connection point. The servo driver 32 drives the reciprocating plunger 33 to move according to a preset frequency and stroke. When the plunger advances, the core layer or filler material enters the coaxial spinneret assembly 4 in a pulsed manner; when the plunger stops, retracts, or the pulse valve closes, the core layer or filler material stops entering or significantly reduces the amount entering. Thus, the core layer or filler material forms mutually spaced internal filler segments within the composite fiber.

[0025] refer to Figure 3The coaxial spinneret 4 includes an outer spinneret 41 connected to the shell melt continuous supply unit 1 and an inner core needle 42 connected to the filler melt supply unit 2. The bottom of the outer spinneret 41 is provided with a spinneret hole 46, and the inner core needle 42 is located at the center of the outer spinneret 41. The inner wall of the outer spinneret 41 and the outer wall of the inner core needle 42 form a shell annular flow channel 43 with an anti-backflow structure (47). A core center flow channel 44 is provided at the center of the inner core needle 42. The outlet of the core center flow channel 44 merges with the shell annular flow channel 43 to form a composite confluence cavity 45 that connects to the spinneret hole 46.

[0026] Combination Figure 2 , 3 7. The core or filler material enters the core center channel 44 of the coaxial spinneret 4 in a pulsed manner, while the shell melt continuously enters the shell annular channel 43 of the coaxial spinneret 4. Finally, the two merge in the composite confluence cavity 45. The shell melt coats the outside of the core or filler material intermittently entering from the core center channel 44. After the composite melt is extruded through the spinneret orifice 46, it forms a composite... Figure 7 The exterior is covered by a continuous shell, and the interior contains a composite melt stream with spaced filler sections.

[0027] refer to Figure 4 The outer diameter stabilizing and shaping unit 5 includes a connected sizing sleeve 52 and a non-contact air flotation sizing structure 54. The sizing sleeve 52 is provided with a micro-perforated sizing ring 53 with cooling holes inside, and the side wall of the sizing sleeve 52 is connected to an external cooling source. The non-contact air flotation sizing structure 54 includes a first sizing cooling zone 55 and a second uniform cooling zone 56, both of which are provided with cooling holes that connect to an external cooling source.

[0028] The outer diameter stabilizing and shaping unit 5 can simultaneously achieve the functions of annular airflow cooling, outer diameter homogenization, and non-contact shaping through its internal annular sizing airflow.

[0029] A micro-orifice sizing ring 53 is positioned downstream of the spinneret 46 and coaxially arranged with the movement path of the composite melt stream. The micro-orifice sizing ring 53 includes an annular body and a sizing channel located at the center of the annular body. The inner diameter of the sizing channel is set according to the outer diameter of the target fiber. A gas distribution chamber connected to a cooling gas source is provided within the annular body. Multiple micro-holes are provided on the inner wall or near the inner wall of the sizing channel. Cooling gas enters the sizing channel through the micro-holes, forming a uniform gas film or air cushion around the fiber. When the composite melt stream passes through the sizing channel, the sizing channel provides a stable outer diameter reference boundary, while the airflow ejected from the micro-holes prevents the melt from directly adhering to the sizing ring and provides circumferential uniform cooling to the outer surface of the fiber. Through this structure, the micro-orifice sizing ring 53 can perform outer diameter calibration and cooling shaping of the composite melt stream under non-contact or weak contact conditions.

[0030] The non-contact air flotation sizing structure 54 is used to center, support, cool, and stabilize the outer diameter of a composite melt stream without direct contact with molten or semi-molten fibers. This structure may include a porous air flotation sleeve, an annular air flotation cavity, and circumferentially distributed micro-hole jet nozzles or annular slit jet nozzles. During operation, compressed air, temperature-controlled air, or inert gas is uniformly ejected from the micro-holes or slits of the air flotation sizing structure 54, forming a stable air film around the fiber, suspending or nearly suspending the fiber in the center of the sizing channel. This air film reduces adhesion, scratches, and tensile disturbances caused by contact between molten fibers and solid components, while simultaneously achieving rapid sizing of the outer shell surface through circumferentially uniform cooling, thereby improving fiber outer diameter uniformity and operational stability.

[0031] The first sizing and cooling zone 55 is located downstream of the spinneret orifice 46 of the coaxial spinneret assembly 4, in a region where the composite melt stream still has a relatively high temperature and plasticity. Its main purpose is to perform preliminary sizing and rapid surface cooling on the continuous shell layer before the outer surface of the fiber has completely solidified, so that a stable initial sizing layer is formed on the outer surface of the shell layer. Since the core layer or filler material enters the fiber in a pulsed manner, local volume disturbances are easily generated at the corresponding positions of the internal filler sections. The first sizing and cooling zone 55 can suppress the transmission of these volume disturbances to the outer surface through annular airflow, air flotation sizing, micropore sizing, or local enhanced cooling, thereby reducing external bulges and outer diameter fluctuations.

[0032] The second uniform cooling zone 56 is located downstream of the first sizing cooling zone 55 and is used to further uniformly cool and completely solidify the composite fibers that have completed preliminary sizing. Unlike the first sizing cooling zone 55, which focuses on rapid sizing and suppressing local outer diameter fluctuations, the second uniform cooling zone 56 focuses on reducing the overall fiber temperature, stabilizing the interface between the shell and internal filler sections, reducing residual thermal stress, and ensuring that the fibers reach a state suitable for drawing, guiding, and winding before entering the drawing and collecting unit 7. The second uniform cooling zone 56 can employ continuous ring blowing, temperature-controlled air ducts, cooling air chambers, cooling rollers, or multi-stage cooling channels.

[0033] It should be noted that the first sizing cooling zone 55 is mainly used for sizing and locally strengthening the cooling of the outer surface of the fiber in the early stage of the formation of the internal filler section; the second uniform cooling zone 56 is mainly used for uniform cooling and complete solidification of the fiber as a whole.

[0034] comprehensive Figure 1 and 5 The periodic cooling and solidification unit 6 is equipped with an annular cooling chamber 64, and multiple cooling nozzles 63 are arranged around the inner wall of the annular cooling chamber 64. The cooling nozzles 63 are connected to a cooling medium supply source 61 through a pulse cooling valve 62. The cooling medium supply source 61 can be compressed air, temperature-controlled air, or inert gas, etc., and is supplied to the cooling nozzles 63 through the cooling valve 62. The composite melt stream is completely cooled and shaped in the annular cooling chamber 64. The purpose of arranging multiple cooling nozzles 63 in an annular manner is to cool the fibers evenly from opposite directions, avoiding fiber bending or eccentricity caused by unilateral cooling.

[0035] refer to Figure 6 The drawing and collecting unit 7 includes a guide roller 71, a drawing roller 72, a tension controller 73 and a winding machine 74 arranged in sequence. After the fiber is combed by the guide roller 71, it is transferred to the drawing roller 72 for drawing and sizing. After being regulated by the tension controller 73, it is collected by the winding machine 74.

[0036] After the outer diameter is stabilized and the fibers are cooled and solidified, they are drawn and sized by the drawing roller 72 after passing through the guide roller 71, and then collected by the winding machine 74. The tension controller 73 is used to adjust the force on the fibers during fiber collection to prevent misalignment. The drawing speed v of the drawing roller 72 and the core layer pulse feeding frequency f together determine the spacing L of the internal filler sections. The faster the drawing speed v, the longer the spacing L of the internal filler sections; the higher the core layer pulse feeding frequency f, the shorter the spacing L of the internal filler sections.

[0037] refer to Figure 1 The synchronous control unit 8 includes a controller 81, a human-machine interface 82, a temperature control module 83, a pressure acquisition module 84, a pump speed control module 85, a pulse parameter setting module 86, a phase compensation module 87, and a closed-loop feedback module 88. The target fiber outer diameter, target internal filler segment length, target filler segment spacing, target core layer ratio, shell temperature, core layer temperature, drawing speed, pulse frequency, single pulse volume, and cooling parameters are input through the human-machine interface 82. The controller 81 coordinates shell feeding, core layer pulse, outer diameter shaping, periodic cooling, and drawing collection based on these parameters, and regulates the shell melt continuous supply unit 1, filler melt supply unit 2, core layer pulse feeding unit 3, and drawing collection unit 7 through the temperature control module 83, pump speed control module 85, pulse parameter setting module 86, phase compensation module 87, and closed-loop feedback module 88.

[0038] For example: Given a target composite fiber outer diameter of 300 μm, a target internal filler segment diameter of 150 μm, a target internal filler segment length of 4 mm, a target center-to-center distance of 10 mm between adjacent internal filler segments, and a drawing and collection speed v of 1 m / min. Based on the relationship between the center-to-center distance L of the internal filler segments and the core pulse frequency f (L=v / f), the core pulse frequency f can be calculated to be approximately 100 times / min, or 1.67 Hz. Based on the approximate relationship between the internal filler segment length l and the core pulse duration t (l=v·t), the core pulse duration t can be calculated to be approximately 0.24 s. If the distance from the spinneret 46 to the first sizing cooling zone 55 is 20 mm, and the fiber's running speed in this section is about 1 m / min, then it takes about 1.2 s for the fiber to move from the spinneret 46 to the first sizing cooling zone 55. If the flow lag time of the core layer melt from the core layer pulse feeding unit 3 to the spinneret 46 is about 0.3 s, then the cooling pulse of the periodic cooling and solidification unit 6 can be started with a delay of about 1.5 s relative to the core layer feeding pulse.

[0039] The overall working process of this embodiment is as follows: First, the shell material and core or filler material are added to their respective supply units and heated to a molten or flowable state. Then, the shell metering pump 14 is started, allowing the shell melt to continuously enter the shell annular flow channel 43 of the coaxial spinneret 4. Subsequently, the core pulse feeding unit 3 is started, allowing the core or filler material to intermittently enter the core center flow channel 44 of the coaxial spinneret 4 according to a preset frequency and single pulse volume. The shell melt continuously coats the intermittently entering core or filler material at the spinneret orifice 46, forming a composite melt stream. After leaving the spinneret orifice 46, the composite melt stream is limited in outer diameter by the outer diameter stabilization and shaping unit 5, then phase-matched cooling by the periodic cooling and solidification unit 6, and finally drawn, cooled, and wound by the drawing and collecting unit 7 to obtain a composite fiber with a basically uniform appearance and a bamboo-like segmented filling inside.

[0040] Example 2: Outer Diameter Uniform Control Device with Total Flow Compensation Based on Embodiment 1, this embodiment further incorporates a total flow compensation mechanism to reduce the impact of core layer pulse feeding on fiber outer diameter. Since the core layer or filler material briefly enters the composite melt stream during pulse activation, if the shell flow rate remains constant, the total ejected volume may increase temporarily, leading to slight bulging on the fiber exterior. To address this issue, in this embodiment, a shell bypass pressure relief channel 17 with a controllable back pressure valve is connected in parallel to the shell pressure stabilizing chamber 16. One end of the shell bypass pressure relief channel 17 is connected to the pressure relief port of the shell metering pump 14, and the other end is connected to the coaxial spinneret assembly 4.

[0041] When the core layer pulse feeding unit 3 is turned on, the synchronous control unit 8 synchronously controls the shell layer bypass pressure relief channel 17 to open briefly, or slightly reduces the output of the shell layer metering pump 14, so that the total melt volume entering the spinneret orifice 46 tends to be constant. When the core layer pulse feeding unit 3 is turned off, the shell layer bypass pressure relief channel 17 is closed, and the shell layer metering pump 14 resumes its original output. Through this compensation method, the outer diameter of the corresponding position of the internal filled section and the corresponding position of the unfilled section are more consistent.

[0042] In another implementation, the synchronization control unit 8 does not directly change the shell layer feed rate, but instead makes minor synchronous adjustments to the drawing speed of the drawing roller 72. When the core layer pulse is activated, the drawing speed is briefly increased to offset the local increase in total ejection volume; when the core layer pulse is deactivated, the drawing speed returns to the set value. This method is suitable for operating conditions where the shell layer melt pressure should not be frequently disturbed.

[0043] In another implementation, a shell pressure-stabilizing cavity 16 is used to absorb local pressure fluctuations, allowing the shell material to undergo slight elastic storage or pressure buffering during the core pulse activation, thereby reducing outer diameter fluctuations. These compensation methods can be used individually or in combination.

[0044] Example 3: Internal filler section cleaning device with core layer truncated structure In this embodiment, a core layer cutoff structure 37 is also provided at one end of the pulse valve 36. The core layer cutoff structure 37 can be a high-temperature needle valve, a conical cutoff valve, a miniature shear valve, or an instantaneous retraction mechanism. When the core layer pulse feeding ends, the core layer cutoff structure 37 quickly closes or retracts the core layer material, so that the core layer or packing material is cut off in time at the end of the internal packing section, reducing tailing, wire pulling, and communication between adjacent packing sections.

[0045] For high-viscosity core materials or filler-containing composite melts, the viscoelasticity of the material can easily cause tailing after the pulse ends, resulting in unwanted connecting filaments between the internal filler segments. The core layer truncating structure 37 improves the clarity of the internal filler segment boundaries, giving the fiber a more bamboo-like segmented morphology in its longitudinal cross-section. Simultaneously, because this truncating process occurs within the continuous shell coating, it avoids creating obvious cuts or abrupt changes in outer diameter on the fiber surface.

[0046] Example 4: Periodic Cooling and Phase Compensation Control In this embodiment, the synchronous control unit 8 is equipped with a phase compensation module 87. There is a flow lag between the core layer or filler material and the spinneret orifice 46, and there is also a travel time between the composite melt stream and the spinneret orifice 46 and the periodic cooling and solidification unit 6. Therefore, the cooling pulse and the core layer feeding pulse do not necessarily occur simultaneously, and phase compensation is required based on the time it takes for the internal filler section to reach the cooling zone.

[0047] The phase compensation module 87 calculates the advance or delay of the cooling pulse relative to the core layer feeding pulse based on the core layer channel length, core layer material viscosity, core layer pulse pressure, spinneret speed, draw speed, and the distance from the spinneret orifice 46 to the cooling zone. By adjusting the phase difference, the periodic cooling and solidification unit 6 provides enhanced cooling precisely when the internal filler section reaches the cooling zone. This prevents excessive diffusion of the core layer or filler material and avoids premature cooling that could lead to an overly hard shell, inability to properly embed the core layer section, or poor interfacial bonding.

[0048] During calibration, samples can be obtained by spinning at low speed, and the actual position of the internal filler segments can be determined by longitudinal slicing, microscopic observation, ultrasonic testing, X-ray fluoroscopy, or resistance change detection. If lag in cooling is detected, resulting in blurred boundaries of the filler segments, cooling should be initiated earlier; if premature cooling is detected, resulting in short internal filler segments or interface defects, cooling should be delayed or the cooling intensity reduced.

[0049] Example 5: Online Detection and Closed-Loop Control Device This embodiment adds an online detection unit 9 based on any of the schemes in Embodiments 1 to 4. The online detection unit 9 is located downstream of the outer diameter stabilization and shaping unit 5 and the periodic cooling and solidification unit 6, preferably at a position before the fiber has completed initial cooling but has not yet entered the winding machine 74. (Reference) Figure 1 The online detection unit 9 includes an outer diameter detection mechanism, a temperature detection mechanism, and an internal structure detection mechanism; Outer diameter measurement mechanisms include laser diameter gauges or cameras, which obtain the fiber outer diameter and its fluctuation in real time by measuring the fiber profile; The temperature detection mechanism includes an infrared temperature sensor, which detects the surface temperature of the fiber after it leaves the cooling zone. Internal structure inspection mechanisms include ultrasonic testing, resistance testing, capacitance testing, X-ray fluoroscopy, and near-infrared testing.

[0050] When a bulge is detected in the fiber outer diameter at the corresponding position of the internal filler section, the closed-loop feedback module 88 controls the synchronous control unit 8 to reduce the single pulse volume of the core layer, reduce the core layer pulse pressure, increase the shell layer bypass pressure relief, enhance the sizing airflow, or increase the drafting speed. When an undersized outer diameter or over-drafting is detected at the corresponding position of the unfilled section, the closed-loop feedback module 88 can reduce the drafting speed, increase the shell layer feed rate, or weaken the sizing airflow. When a tail connection is detected between internal filler sections, the closed-loop feedback module 88 can shorten the core layer pulse duration, strengthen the core layer cutoff, or pre-cool and solidify. When the length of the internal filler section is insufficient, the pulse duration can be extended, the single pulse volume increased, or the drafting speed reduced.

[0051] When the core or filler material is conductive, the position and spacing of the internal filler segments can be determined by periodic changes in resistance or conductivity. When the density or absorption characteristics of the core or filler material differ significantly from those of the shell material, X-ray or ultrasonic methods can be used to detect the distribution of the internal filler segments. The online detection unit 9 feeds the detection results back to the synchronous control unit 8 to correct the core pulse feeding parameters, cooling phase, sizing airflow intensity, and drawing speed. Through the closed-loop control described above, this embodiment can simultaneously ensure the uniformity of the fiber's external diameter and the stability of its internal bamboo-like segmented structure, making it suitable for continuous production.

[0052] Example 6: Segmented distribution of composite fibers within functional materials In this embodiment, the shell material is thermoplastic polyurethane, and the core or filler material is a conductive composite material containing conductive carbon black, carbon nanotubes, or graphene. The resulting fiber can be called conductive filler composite fiber or conductive composite fiber, commonly known as conductive fiber or sensing fiber. Since the conductive material only forms periodic filler segments within the fiber, the resulting fiber can be used in flexible sensors, antistatic fabrics, or wearable electronic materials. This type of material is fed through a core-layer pulse, and the conductive composite material only forms periodic filler segments within the fiber, while the shell continuously covers the outside. The resulting fiber has an appearance similar to ordinary constant-diameter fibers, with good flexibility and weavability; the internal conductive segments can form segmented conductivity, pressure response, or localized sensing functions.

[0053] In another embodiment, the core layer or filler material is a phase change composite material, such as paraffin wax, fatty acid esters, polyethylene glycol, or phase change microcapsules, so that the phase change components are distributed along the fiber axis in the form of internal filler segments. The resulting fiber can be called a phase change material composite fiber or a heat storage and temperature regulation composite fiber, commonly known as a temperature regulation fiber or a heat storage fiber. This type of fiber can be used in thermal management fabrics, thermal insulation and temperature regulation materials, or localized heat storage materials. This structure of such materials can provide localized heat storage and thermal buffering functions while maintaining the uniformity and flexibility of the fiber outer diameter.

[0054] In another embodiment, the core layer or filler material is a composite material containing magnetic particles, such as iron(III) oxide, ferrite, carbonyl iron powder, or other magnetic particles, which creates periodic magnetic response segments within the fiber. The resulting fiber can be called a magnetically responsive composite fiber or a magnetically filled composite fiber, commonly known as a magnetic fiber. This type of fiber can be used in magnetically responsive driven materials, electromagnetic functional fabrics, or identifiable composite materials. Because the magnetic material is discontinuously filled, this type of material can reduce the adverse effects of the magnetic filler on the overall flexibility and tensile properties of the fiber.

[0055] In other embodiments, the core layer or filler material can also be a foamed composite material, an antibacterial composite material, a drug carrier composite material, an adsorbent composite material, or a reinforced composite material. The resulting fibers can be called microporous foamed composite fibers or porous composite fibers, commonly known as lightweight porous fibers or foamed fibers. These fibers can be used in sound-absorbing and heat-insulating materials, lightweight filling materials, or filter materials. Through internal segmented distribution, these materials can impart local functions or periodic response characteristics to the fibers without significantly changing their appearance and outer diameter.

[0056] The above embodiments are merely illustrative of the principles and effects of this patent application and are not intended to limit this patent application. Any person skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this patent application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this patent application shall still be covered by the claims of this patent application.

Claims

1. An apparatus adapted for preparing melt-spun slub-like fibers, characterized in that, include: The feeding system, coaxial spinneret assembly (4), outer diameter stabilization and shaping unit (5), periodic cooling and solidification unit (6), and drawing and collecting unit (7) are connected in sequence under the control of the synchronous control unit (8). The feeding system is divided into two parts: a shell melt continuous supply unit (1) and a filler melt supply unit (2), both of which are connected to the coaxial spinneret assembly (4). A core layer pulse feeding unit (3) is also provided between the filler melt supply unit (2) and the coaxial spinneret assembly (4). The synchronous control unit (8) controls the supply speed of the shell melt continuous supply unit (1) and the core layer pulse feeding unit (3). The coaxial spinneret assembly (4) integrates the fibers to form bamboo-like fibers. After being cooled by the periodic cooling and solidification unit (6), the fibers are collected by the drawing and collecting unit (7). It also includes an online detection unit (9), which monitors the operating power of the shell melt continuous supply unit (1), the filler melt supply unit (2), the core layer pulse supply unit (3), the outer diameter stabilization and shaping unit (5), the periodic cooling and solidification unit (6) and the stretching and collecting unit (7), and feeds it back to the synchronous control unit (8) for regulation.

2. The apparatus for preparing melt-spun bamboo-like fibers according to claim 1, characterized in that: The shell melt continuous supply unit (1) includes a shell hopper (11), a shell heater (13), a shell melting chamber (12), a shell metering pump (14), and a shell pressure stabilizing chamber (16) connected in sequence. The shell hopper (11) receives external raw materials, heats them through the shell heater (13) to form shell melt, and then transports them to the shell melting chamber (12). The shell melt in the shell melting chamber (12) is transported to the shell pressure stabilizing chamber (16) through the shell metering pump (14). The shell pressure stabilizing chamber (16) is connected to the coaxial spinneret assembly (4). A shell pressure sensor (15) is also provided between the shell metering pump (14) and the shell pressure stabilizing chamber (16) to monitor and detect the feeding pressure and flow stability of the shell melt. A shell bypass pressure relief channel (17) with a controllable back pressure valve is also provided in parallel with the shell pressure stabilizing chamber (16). One end of the shell bypass pressure relief channel (17) is connected to the pressure relief port of the shell metering pump (14), and the other end is connected to the coaxial spinneret assembly (4).

3. The apparatus for preparing melt-spun slub-like fibers according to claim 1, characterized in that: The filler melt supply unit (2) includes a core layer hopper (21), a core layer melting chamber (22), and a core layer buffer chamber (24). A core layer heater (23) is installed in the core layer buffer chamber (24). The core layer hopper (21) receives raw materials and transports them to the core layer melting chamber (22). After being heated by the core layer heater (23) to form a core layer melt, the melt flows into the core layer buffer chamber (24) and is then transported to the coaxial spinneret assembly (4) by the core layer pulse feeding unit (3). A core layer pressure sensor (25) is installed inside the core layer buffer cavity (24).

4. The apparatus for preparing melt-spun bamboo-like fibers according to claim 1, characterized in that: The core layer pulse feeding unit (3) is a high temperature servo plunger pulse pump (31). The high temperature servo plunger pulse pump (31) includes a pulse valve (36), a servo driver (32), a reciprocating plunger (33) and a one-way valve group (34) connected in sequence. A heat insulation sleeve (35) is provided at the connection. A core layer cut-off structure (37) is also provided at one end of the pulse valve (36).

5. The apparatus for preparing melt-spun bamboo-like fibers according to claim 1, characterized in that: The coaxial spinneret (4) includes an outer spinneret (41) connected to the shell melt continuous supply unit (1) and an inner core needle (42) connected to the filler melt supply unit (2). The bottom of the outer spinneret (41) is provided with a spinneret hole (46), and the inner core needle (42) is located at the center of the outer spinneret (41). The inner wall of the outer spinneret (41) and the outer wall of the inner core needle (42) form a shell annular flow channel (43) with an anti-backflow structure (47). A core center flow channel (44) is provided at the center of the inner core needle (42). The outlet of the core center flow channel (44) merges with the shell annular flow channel (43) to form a composite confluence cavity (45) that connects to the spinneret hole (46).

6. The apparatus for preparing melt-spun bamboo-like fibers according to claim 1, characterized in that: The outer diameter stabilizing and shaping unit (5) includes a connected sizing sleeve (52) and a non-contact air flotation sizing structure (54). The sizing sleeve (52) is provided with a micro-perforated sizing ring (53) with cooling holes inside, and the side wall of the sizing sleeve (52) is connected to an external cooling source; The non-contact air flotation sizing structure (54) includes a first sizing cooling zone (55) and a second uniform cooling zone (56), both of which are provided with cooling holes that connect to an external cooling source.

7. The apparatus for preparing melt-spun bamboo-like fibers according to claim 1, characterized in that: The periodic cooling and solidification unit (6) is provided with an annular cooling chamber (64), and multiple cooling nozzles (63) are arranged around the inner wall of the annular cooling chamber (64). The cooling nozzles (63) are connected to the cooling medium supply source (61) through the pulse cooling valve (62).

8. The apparatus for preparing melt-spun bamboo-like fibers according to claim 1, characterized in that: The drawing and collecting unit (7) includes a guide roller (71), a drawing roller (72), a tension controller (73), and a winding machine (74) arranged in sequence. The fiber is combed by the guide roller (71) and then transferred to the drawing roller (72) for drawing and sizing. After being regulated by the tension controller (73), it is collected by the winding machine (74).

9. The apparatus for preparing melt-spun slub-like fibers according to claim 1, characterized in that: The synchronous control unit (8) includes a controller (81), a human-machine interface (82), a temperature control module (83), a pressure acquisition module (84), a pump speed control module (85), a pulse parameter setting module (86), a phase compensation module (87), and a closed-loop feedback module (88).

10. The apparatus for preparing melt-spun bamboo-like fibers according to claim 1, characterized in that: The online detection unit (9) includes an outer diameter detection mechanism, a temperature detection mechanism, and an internal structure detection mechanism; Outer diameter measurement mechanisms include laser diameter gauges or cameras, which obtain the fiber outer diameter and its fluctuation in real time by measuring the fiber profile; The temperature detection mechanism includes an infrared temperature sensor, which detects the surface temperature of the fiber after it leaves the cooling zone. Internal structure inspection mechanisms include ultrasonic testing, resistance testing, capacitance testing, X-ray fluoroscopy, and near-infrared testing.

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