Preparation method of orange petal type composite fiber and spinneret plate assembly

Abstract

The invention belongs to the technical field of chemical fiber manufacturing, and particularly discloses a preparation method of orange petal type composite fibers and a spinneret plate assembly. The spinneret plate assembly comprises a first distribution plate, a second distribution plate, a third distribution plate and a spinneret plate which are sequentially overlapped, a boss is arranged on the lower surface of the third distribution plate, and small through holes and small grooves which are alternately arranged at intervals and communicated with two melt runners respectively are formed in the boss. During preparation, two polymer melts are distributed step by step through the distribution plates, are pre-arranged into a spaced and parallel form through the boss structures, then are compositely extruded in the spinneret orifices, and are cooled and cured to obtain the orange petal type composite fiber. According to the invention, the melt pre-arrangement structure is arranged at the upstream of the final composite point, so that the accurate control on the form of the two-component interface is realized, the orange petal type fiber with a regular section and a clear interface can be stably spun, and a foundation is laid for the subsequent efficient and uniform production of high-quality superfine fiber.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chemical fiber manufacturing, and particularly relates to a preparation method of segmented pie (also known as split type, spaced parallel type) composite fibers for producing superfine fibers, and a special jet plate assembly for realizing the method. BACKGROUND

[0002] Segmented pie composite fibers are an important type of bicomponent composite fibers, and are characterized in that two incompatible polymer components are alternately and spacedly arranged like orange petals on the cross section of a fiber. This unique structural design is not intended to form an integrated filament, but to separate the two components along the interface through subsequent fiber opening processes such as water jetting and alkali reduction, so as to obtain superfine fiber bundles with extremely fine fineness (up to 0.5 dtex and below) and large specific surface area. Non-woven materials made of such superfine fibers have extremely soft hand feeling, excellent water absorption performance, high filtration efficiency and good mechanical properties, and are therefore widely used in high-end fields such as high-grade wiping cloth, synthetic leather base cloth, high-performance filtration material and lithium battery separator.

[0003] Composite spinning is the core technology for mass production of segmented pie fibers, and the key lies in delivering and distributing two different polymer melts (such as polyester PET and polyamide PA6) through a precise jet plate assembly, and finally extruding them in a preset and stable spaced parallel form at the outlet of the jet hole. The structural design of the jet plate assembly directly determines the interface form, uniformity and stability of the melt composite, and is a decisive factor affecting whether the cross section of the final fiber can be regularly shaped and whether subsequent fiber opening can be efficiently performed.

[0004] In order to prepare segmented pie composite fibers, various design schemes of jet plate assemblies have been proposed in the industry. These schemes are mainly aimed at solving the distribution and composite of two melts.

[0005] A common design idea is to use a multi-layer distribution plate structure. For example, some prior art discloses a composite spinning assembly including a feeding plate, multiple distribution plates and a jet plate, which distributes A and B melts from the center to the periphery or at different radii through annular grooves, strip-shaped distribution grooves and through holes on different plate pieces, and finally guides them to the jet holes. Another more targeted scheme is specially used for preparing petal-shaped cross section fibers, and the assembly includes a distribution plate and a jet plate, which forms a designed petal shape and contacts each other in the cross section of the two components through the setting of shaping holes and channels on the distribution plate.

[0006] In addition, the latest technology development focuses on the precise control of the composite interface. For example, some inventions propose inserting a very thin component separator plate into the spinneret to separate the flow channel space in the spinneret into two non-communicating parts, thereby directly controlling the interface morphology of the two components before extrusion, so as to produce different interface structures of side-by-side composite fibers. This reflects the current technology towards more precise and more active interface regulation.

[0007] Although the existing technology has achieved the basic production of segmented pie fibers, there are still some technical problems to be solved in meeting the demand of large-scale industrial production of high-quality and high-uniformity ultra-fine fibers. These problems are collectively directed at the control of the "last stage" of the melt flow and compounding inside the spinneret assembly:

[0008] 1. Insufficient interface morphology pre-control and uneven fibrillation effect: The core of many multi-layer distribution schemes is to "transport" the melt to the spinneret, but the control of the microscopic arrangement state of the two melts at the moment of reaching the spinneret is not accurate enough. The melt lacks effective "preforming" guidance before the final compounding, resulting in unstable interface state at the entrance of the spinneret, and poor consistency of the size and shape of the segmented pie in the cross-section of the spun fiber. This directly affects the effectiveness of the subsequent fibrillation process, which may lead to incomplete fibrillation or uneven thickness of the ultra-fine fiber bundle, and cannot guarantee the stability of the performance of the end product.

[0009] 2. Complex flow channel design, prone to flow disturbance and stagnation: Although the complex multi-layer distribution flow channel can achieve extensive distribution of the melt, the long flow path and frequent changes of direction may increase the melt resistance and cause local flow dead angles. For two melts with different viscosity and rheological properties (such as PET and PA6), this design may amplify the unevenness of their flow, resulting in large differences in fiber fineness extruded from different spinnerets. At the same time, local stagnation in the flow channel may cause thermal degradation of the polymer, affecting the quality of the fiber.

[0010] 3. Challenges in assembly versatility and stability: Some designs that use fixed separators or specific shaped holes, although they can obtain a specific interface, often have limited flexibility when it comes to fixed components or specific number of segmented pies. When changing raw materials or adjusting the segmented pie morphology, the entire key component may need to be replaced, increasing production costs and process debugging difficulty.

[0011] In summary, the existing technology has not yet perfectly solved the key problem of how to achieve precise positioning, stable arrangement and interface pre-forming of two polymer melts before the final compounding in a relatively simple and efficient spinneret assembly. This hinders the further improvement of segmented pie composite fibers in cross-sectional uniformity, fibrillation efficiency and production stability.

[0012] Therefore, the technical problem of the present application is to provide a new type of orange segment composite fiber preparation method and spinneret assembly to overcome the above-mentioned defects. The assembly should be able to ensure that the two melts are precisely distributed and arranged in a preset interval side-by-side form before entering the final spinning hole, i.e. at a critical position, so as to directly and stably spin orange segment composite fibers with regular cross-section and clear interface, thereby laying a foundation for subsequent efficient and uniform production of ultrafine fibers.

[0013] It should be noted that the information disclosed in this background section is only intended to deepen the understanding of the overall background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art. SUMMARY

[0014] In view of the deficiencies of the existing orange segment composite fiber spinneret assembly in terms of melt interface precise pre-control, flow uniformity and structural simplicity, the present application aims to provide a new type of orange segment composite fiber spinneret assembly and preparation method. The primary purpose of the present application is to design a core structure with melt pre-arrangement function, so that the two polymer melts are precisely distributed and fixed in a preset interval side-by-side form before entering the final spinning hole, thereby directly spinning orange segment composite fibers with regular cross-section and clear interface. The further purpose of the present application is to optimize the melt distribution path and improve the uniformity and stability of the discharge of each spinning hole, so as to be suitable for large-scale production of high-quality ultrafine fibers. Another purpose of the present application is to provide an orange segment composite fiber preparation method with simple process flow and high controllability.

[0015] To achieve the above-mentioned application purposes, the present application adopts the following technical solutions:

[0016] In a first aspect, the present application provides an orange segment composite fiber spinneret assembly, comprising a first distribution plate, a second distribution plate, a third distribution plate and a spinneret plate which are sequentially stacked from top to bottom and in fluid communication;

[0017] The first distribution plate is provided with a first annular flow channel and a second annular flow channel which are isolated from each other and are used for receiving and distributing a first melt and a second melt, respectively; a plurality of first through holes and second through holes which penetrate the first distribution plate are respectively arranged at intervals in the first annular flow channel and the second annular flow channel;

[0018] The upper surface of the second distribution plate is provided with a plurality of first flow guide grooves and second flow guide grooves corresponding to the positions of the first through holes and the second through holes, respectively, and the lower surface is provided with a plurality of third through holes and fourth through holes which communicate with the first flow guide grooves and the second flow guide grooves, respectively, and guide the melts downward;

[0019] The upper surface of the third distribution plate is provided with at least one circle of first annular material grooves and at least one circle of second annular material grooves which are spaced from each other and correspond to the positions of the third through hole and the fourth through hole; the lower surface of the third distribution plate is provided with a downwardly protruding boss, the boss is provided with a plurality of material outlet holes which are in communication with the second annular material grooves and a plurality of material passing grooves which are in communication with the first annular material grooves, and the material outlet holes and the material passing grooves are alternately and spacedly arranged on the lower end surface of the boss;

[0020] The spinneret is provided with a spinneret hole, the lower end of the boss extends into the upper part of the spinneret hole, so that the second melt and the first melt from the material outlet holes and the material passing grooves are combined in the spinneret hole in the form of spaced parallel and are extruded.

[0021] The core idea of the present application is to set a "preforming station" with a precise microstructure upstream of the final composite point (spinneret hole) to forcibly arrange the last form of the two melts.

[0022] The assembly comprises a first distribution plate, a second distribution plate, a third distribution plate and a spinneret which are sequentially stacked from top to bottom and are in fluid communication. The first distribution plate is provided with a first annular flow channel and a second annular flow channel which are isolated from each other and are used to receive and initially circumferentially distribute two melts. The second distribution plate converts the circumferentially distributed melts into a plurality of streams which are directed to different radial positions by the radial strip-shaped first and second flow guide grooves on the surface and the through hole at the bottom. The third distribution plate is the key of the innovation, the upper surface thereof is provided with at least one circle of first annular material grooves and at least one circle of second annular material grooves which are spaced from each other and correspond to the positions of the streams received; the lower surface thereof is provided with a downwardly protruding boss, the boss is provided with a plurality of material passing grooves which are in communication with the first annular material grooves and a plurality of material outlet holes which are in communication with the second annular material grooves. The key is that the material outlet holes and the material passing grooves are alternately and spacedly arranged on the lower end surface of the boss. The spinneret is provided with a spinneret hole, the lower end of the boss extends into the upper part of the spinneret hole, so that the two melts which are prearranged can be directly combined in the spinneret hole in the form of pre-set spaced parallel and are extruded.

[0023] Further, the first annular flow channel and the second annular flow channel on the first distribution plate are concentric annular grooves, and the diameter of the second annular flow channel is greater than that of the first annular flow channel. This structure is beneficial to achieving natural and uniform circumferential distribution by using the gravity and pressure of the melts, simplifies the flow channel design, reduces the flow dead angle and pressure unevenness caused by complex flow channels, and lays a solid foundation for subsequent uniform distribution.

[0024] Further, the first and second flow guide grooves on the second distribution plate are radial strip grooves, and the length of the first flow guide groove is greater than that of the second flow guide groove. This design precisely matches the annular flow channels of different diameters on the first distribution plate, realizes efficient and turbulence-free flow transfer of the melt from the annular space to a specific radial position, and ensures that the two melt flows are both isolated and precisely positioned in space.

[0025] Further, the third distribution plate is provided with N+1 first annular material grooves and N second annular material grooves, the second annular material grooves are located between two first annular material grooves, wherein N≥1, and all annular material grooves are distributed concentrically along the radial direction of the third distribution plate. This "A-B-A" sandwich radial layout can make the distribution of the two components in the finally formed orange-segment-shaped fiber cross-section more balanced and the mechanical structure more stable, which is beneficial to obtaining ultra-fine fiber bundles with more uniform thickness during subsequent fiber splitting.

[0026] Further, the material passing groove is a groove opened on the side surface of the boss and extending to the lower end surface thereof, and the discharge hole is a vertical micro-hole penetrating through the boss. The groove is easy to process, and the flow passage cross section can be flexibly designed to adjust the flow rate; the vertical micro-hole can stabilize the flow direction of the melt. The combination of the two can achieve precise positioning and arrangement of the melt in a two-dimensional plane with the simplest mechanical structure, which is the core carrier of the "preforming" function.

[0027] Further, the number of discharge holes and material passing grooves is 4-12, and they are uniformly and alternately arranged. This range ensures that the number of orange segments formed is moderate, which can effectively reduce the fineness of single ultra-fine fiber, and avoid the problem of too low interface strength and high spinning breakage rate caused by too many segments. Uniform arrangement is a direct guarantee for obtaining regular and symmetrical fiber cross-section.

[0028] Further, the upper part of the spinning hole is designed as a tapered or straight-cylindrical guide section, the bottom of the spinning hole is provided with a central blocking piece, each side of the central blocking piece is formed with an annular slit, the central blocking piece is connected with the wall of the spinning hole through two ear connecting pieces, the width of the ear connecting piece is much smaller than the circumference of the annular slit; the lower end of the boss of the third distribution plate extends into the guide section of the upper part of the spinning hole, and an annular gap for the flow of the melt is left between them. This design ensures that the melt that has been pre-arranged from the lower end surface of the boss can be smoothly introduced into the spinning hole, avoiding turbulence or interface disturbance at the inlet. After being extruded in the spinning hole, the first melt and the second melt become a hollow orange-segment-shaped fiber.

[0029] In the second aspect, the application provides a method for preparing orange-segment-shaped composite fibers based on the above-mentioned spinneret plate assembly, and the core step is to realize the ultimate composite form control of the melt by using the pre-arrangement function of the boss.

[0030] The method comprises the following steps:

[0031] S1: melt the first polymer and the second polymer respectively to obtain a first melt and a second melt;

[0032] S2: independently introduce the first melt and the second melt into the first annular flow channel and the second annular flow channel of the first distribution plate of the spinneret assembly; the first melt (A) and the second melt (B) flow out through the first through hole and the second through hole respectively and correspondingly flow into the first flow guide groove and the second flow guide groove on the second distribution plate;

[0033] S3: after being distributed by the second distribution plate, the two melts enter the corresponding first annular material groove and the second annular material groove on the third distribution plate respectively;

[0034] S4: the first melt flows out through the material passing groove on the boss, and the second melt flows out through the material outlet hole on the boss, and the two are compounded in a preset form of interval and parallel at the spinneret orifice inlet of the spinneret;

[0035] S5: the compounded melt flows through the spinneret orifice and is extruded, cooled and solidified to form an orange petal-shaped composite fiber.

[0036] Further, the first polymer is polyethylene terephthalate (PET), and the second polymer is polyamide 6 (PA6) or polyamide 66 (PA66). This is the most classic and highest commercial value combination in the field of ultra-fine fibers. The assembly provided by the application can perfectly adapt to the two polymers with different rheological properties, ensure clear interface and stable compounding, and provide reliable guarantee for producing high-quality PET / PA ultra-fine fibers.

[0037] Further, in step S5, the extruded nascent fiber is subjected to cooling, oiling, drafting and winding processes to obtain an orange petal-shaped composite fiber filament. This clearly shows that the method of the application can be directly integrated into the existing mature spinning process, without the need for large-scale modification of the existing production line, greatly reducing the industrialization implementation threshold and cost.

[0038] Further, it further comprises a step S6 of opening the fiber treatment of the orange petal-shaped composite fiber obtained in step S5, and the opening fiber treatment is mechanical water jet treatment or chemical alkali reduction treatment, so that the interval and parallel interface of the first melt and the second melt is separated to obtain an ultra-fine fiber bundle. After the composite fiber is made, a step of opening fiber treatment such as mechanical water jet or chemical alkali reduction is further included. This step extends the protection scope of the application from "precursor fiber" to the final "ultra-fine fiber" product. It clearly defines and protects the key technical path of using the fiber produced by the application to manufacture terminal high-value-added products, forming a complete technical chain protection from raw materials, equipment to products.

[0039] Compared with the prior art, the present application has the following remarkable beneficial effects:

[0040] 1. The quality of fiber cross-section is significantly improved: The core of the present application is the "boss pre-arrangement structure", which forcibly fixes the spatial position of the melt before it enters the spinneret hole. This fundamentally solves the problem of random and unstable interface state of the melt at the entrance of the spinneret hole in traditional designs, thereby enabling the stable and continuous spinning of regular, uniform-sized, and clear-interface segmented pie-shaped composite fibers, providing a fundamental guarantee for obtaining uniform-thickness ultra-fine fibers subsequently.

[0041] 2. The working stability and uniformity of the assembly are more optimal: Through the three-level distribution and guidance system of "first distribution plate (circumferential distribution) → second distribution plate (radial distribution) → third distribution plate (collection and preforming)", the melt flow path is logically clear and each part has its own function. Compared with complex multi-layer interlaced flow channels, the structure of the present application reduces flow resistance and stagnation risk, ensuring the consistency of melt pressure and flow to each boss structure, thereby greatly improving the uniformity of the whole spinneret plate and the stability of the production process.

[0042] 3. The device structure is simplified and maintenance is convenient: The most precise "preforming" function is concentrated on the boss of the third distribution plate, while the other distribution plates mainly undertake the task of flow guiding. This modular design makes the core functional components relatively simple in structure, easy to process and detect. At the same time, when the number or shape of segmented pie needs to be adjusted, theoretically, it can be realized by replacing or modifying the third distribution plate (especially the boss part), improving the versatility and flexibility of the equipment and reducing the maintenance cost.

[0043] 4. The preparation method is efficient and the product has high added value: The process flow of the method is smooth, has good compatibility with existing spinning equipment, and is easy to realize industrialization. Especially through the opening process, high-quality segmented pie-shaped composite fibers spun by the present application can be directly converted into high-value-added ultra-fine fiber products, making the entire technical solution have complete commercial competitiveness from core equipment to high-end products. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to make the above-mentioned purposes, technical solutions and beneficial effects of the present application clearer, the present application will be described in detail below in conjunction with the drawings and specific embodiments. It should be noted that the drawings are drawn in a simplified or schematic manner and are only used to assist in explaining the concept of the present application and should not be understood as limiting the scope of protection of the present application. The same reference numerals in the drawings represent the same or similar parts.

[0045] Figure 1 is a perspective structural schematic diagram of an embodiment of the segmented pie-shaped composite fiber spinneret plate assembly of the present application.

[0046] Figure 2 is an exploded view. Figure 1

[0047] Figure 3 is a front structural schematic view of the second distribution plate. Figure 1

[0048] Figure 4 is a front structural schematic view of the third distribution plate. Figure 1

[0049] Figure 5 is a back structural schematic view of the third distribution plate. Figure 1

[0050] Figure 6 is a partial enlarged view of part B. Figure 5

[0051] Figure 7 is a cross-sectional view of the spinneret. Figure 1

[0052] Figure 8 is a partial enlarged view of the spinneret hole in the B direction. Figure 7

[0053] Figure 9 is a cross-sectional view. Figure 1

[0054] Figure 10 is a cross-sectional structural schematic view of the orange petal-shaped composite fiber prepared by using the spinneret assembly of the present application.

[0055] BRIEF DESCRIPTION OF DRAWINGS

[0056] 1, first distribution plate; 11, first annular flow channel; 12, second annular flow channel; 13, first through hole; 14, second through hole; 2, second distribution plate; 21, first flow guide groove; 22, second flow guide groove; 23, third through hole; 24, fourth through hole; 3, third distribution plate; 31, first annular material groove; 32, second annular material groove; 33, boss; 331, discharge hole; 332, material passing groove; 4, spinneret; 41, spinneret hole; 410, central closure piece; 411, annular slit; 412, ear connecting piece; 5, center bolt; 6, positioning pin; A, first melt; B, second melt. DETAILED DESCRIPTION

[0057] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings and through specific embodiments. Those skilled in the art can understand that these descriptions are exemplary and are not intended to limit the protection scope of the present application.

[0058] ​​​​​​​​The application provides a spinneret assembly and a preparation method capable of efficiently and stably producing orange-segment-shaped composite fibers. Figure 1 and Figure 2 As shown in the drawings, the spinneret assembly is circular as a whole, mainly composed of four precisely machined plate pieces aligned from top to bottom by positioning pins 6 and fastened together by a center bolt 5. The four plate pieces are, in order, a first distribution plate 1, a second distribution plate 2, a third distribution plate 3, and a spinneret plate 4. The melt flow follows a top-down path, and each layer of plate piece bears a specific fluid distribution and forming function.

[0059] The first distribution plate 1 serves as the primary distribution hub of the melt, and its core feature is that the upper surface is machined with two concentric annular channels with different diameters. The inner side with a smaller diameter is the first annular channel 11, and the outer side with a larger diameter is the second annular channel 12. The two channels are physically completely isolated and do not communicate with each other. The first melt A (for example, polyester PET) is introduced into the first annular channel 11 through the upper interfacing feeding device (not shown), while the second melt B (for example, polyamide 6 PA6) is independently introduced into the second annular channel 12. This concentric annular channel design cleverly utilizes the pressure and flowability of the melt itself, achieving primary uniform distribution of the two components in the circumferential direction and laying a foundation for pressure balance for subsequent fine distribution. As an alternative embodiment, the number of annular channels can be more than two, for example, three or more, to accommodate the needs of three-component or more-component composite spinning, and the channels still need to be isolated from each other. A plurality of first through holes 13 and second through holes 14 are arranged in the first annular channel 11 and the second annular channel 12, respectively, penetrating the first distribution plate 1.

[0060] The second distribution plate 2 receives the circumferential distribution melt from the first distribution plate 1 and converts it into multiple independent streams pointing to specific radial positions. Figure 3As shown in the top view, several radially extending strip-shaped guide channels are machined on the upper surface of the plate. These guide channels are of two specifications: the longer ones, extending close to the outer edge of the plate, are the first guide channels 21, whose positions correspond one-to-one with the first through holes 13 in the first annular flow channel 11; the shorter ones, located in the middle of the plate, are the second guide channels 22, whose positions correspond one-to-one with the second through holes 14 in the second annular flow channel 12. The first guide channels 21 and the second guide channels 22 are arranged alternately and at intervals in the circumferential direction. On the lower surface of the second distribution plate 2, corresponding to the positions of each first guide channel 21 and second guide channel 22, multiple third through holes 23 and fourth through holes 24 are machined to communicate with them. When the melt falls from the annular flow channel of the first distribution plate 1 into the corresponding guide channel, it will diffuse and fill along the strip-shaped channel, and then flow vertically downward from each through hole under pressure. This design enables the transformation of fluid form and precise spatial positioning from "surface" (annular flow channel) to "line" (strip groove) and then to "point" (through hole). In a preferred embodiment, to compensate for differences in fluid resistance, the diameter of the third through hole 23 located on different radial layers can be designed to be different. For example, the diameter of the through holes in the outermost and innermost rings can be slightly smaller than the diameter of the through holes in the middle rings to ensure the uniformity of all outlet flow rates.

[0061] The third distribution plate 3 is the innovative core of the entire assembly, undertaking the crucial mission of performing the final "pre-arrangement" of the two melts. For example... Figure 4 and Figure 5 As shown, its upper surface, corresponding to the outlet positions of each through hole in the second distribution plate 2, is machined with mutually spaced annular collecting grooves. Specifically, corresponding to the positions of all third through holes 23, four rings of first annular material grooves 31 are provided; corresponding to the positions of all fourth through holes 24, three rings of second annular material grooves 32 are provided. In this embodiment, the second annular material grooves 32 are located exactly between two rings of first annular material grooves 31, forming an "ABA" sandwich radial layout. This layout is beneficial to the mechanical balance of the final fiber cross-section structure.

[0062] The essence of this invention is concentrated on the lower surface of the third distribution plate 3. For example... Figure 5 and Figure 6 Clearly shown, on its lower surface, corresponding to each spinning point (i.e., the location where a spinneret will eventually form), there is a downward-protruding cylindrical boss 33. This boss 33 is a "forming mold" before melt bonding. Figure 6As shown in the enlarged view of the local area, a plurality of (for example, 8) vertical through discharge holes 331 are machined on the lower end surface of the boss 33. The discharge holes 331 are small-diameter through holes, and the upper ends of the small through holes are in communication with the second annular material groove 32 on the upper surface. At the same time, a plurality of material passing grooves 332 corresponding in number and position to the discharge holes 331 are machined on the side wall of the boss 33. The material passing grooves 332 are designed as narrow and long small grooves, which are cut from the upper part of the boss side wall, extend downward and penetrate to the lower end surface of the boss. The upper end of the small groove is in communication with the first annular material groove 31. It is crucial that the discharge holes 331 and the material passing grooves 332 are arranged alternately and spaced apart in a circumferential direction on the lower end surface of the boss 33. They can be strictly one-to-one alternately arranged to form a very regular pattern. As an alternative embodiment, the arrangement is not limited to one-to-one circumferential arrangement, but can also be "two holes and one groove" or "one hole and two grooves" as a repeating unit, or arranged in a non-circular symmetrical pattern (such as rectangular distribution), as long as the core feature of "spaced arrangement" is met, the separation and combination of the melt can be realized. The width of the material passing groove 332 is preferably 0.3-0.5mm, and the depth is 0.4-0.6mm; the diameter of the discharge hole 331 is preferably 0.2-0.4mm.

[0063] The spinneret 4 is located at the bottom layer, and the final forming spinneret holes 41 are machined thereon. As shown in the enlarged view of the local area, Figures 7 to 9As shown, the upper part of the orifice 41 is generally designed as a conical or straight cylindrical guide section, and the bottom of the orifice 41 is provided with a central closure piece 410, which is shaped with an annular slit 411 on each side, and the central closure piece 410 is connected with the wall of the orifice 41 through two ear connectors 412, and the ear connectors 412 are shaped with the annular slit 411 on each side of the central closure piece 410, and the width of the ear connector 412 is much smaller than the circumference of the annular slit 411. The ear connector 412 is used to support the central closure piece 410. A key assembly relationship is that the lower end of the boss 33 of the third distribution plate 3 needs to be accurately inserted into the guide section of the upper part of the orifice 41, and an annular gap for the melt flow is left between the two. This design ensures that the melt that has been pre-arranged and flows out of the lower end surface of the boss 33 can be smoothly introduced into the orifice 41, avoiding turbulence or interface disturbance at the inlet. After the first melt A and the second melt B are extruded through the annular slit 411 of the orifice 41, they finally become a hollow segmented fiber. Because the ear connector 412 is very thin and narrow, about 0.06mm-0.12mm wide, the polymer melt molecular chain is highly stretched and oriented in the thermal flow field, and a large amount of elastic deformation energy is stored inside; when the two melt flows out of the annular slit 411, the constraint suddenly disappears, and the pressure drops to zero, and the previously stretched molecular chain will quickly retract and relax like a released spring, which causes the melt to have a significant "exit expansion" effect, and the expansion direction is exactly directed to the other, and the two highly activated, temperature-uniform, and viscous flow state melts are instantaneously contacted and extruded together, so that the melt flow is not cut into two half-ring filaments, but forms a complete hollow filament.

[0064] Please refer to Figure 2 The connection mode of the spinneret plate assembly is that positioning pin holes are formed on both sides of the edges of each distribution plate and the spinneret plate 4, two positioning pins 6 are sequentially inserted into each plate to realize positioning, and then a bolt 5 arranged at the center is used for fixing. The center of the first distribution plate 1 is designed with a threaded blind hole matched with the bolt 5, and the bolt 5 is sequentially inserted into the spinneret plate 4, the third distribution plate 3, the second distribution plate 2, and then fixed by being screwed into the threaded blind hole in the center of the first distribution plate 1.

[0065] The working principle of the assembly is combined with the preparation method Figure 9The cross-sectional view is illustrated as follows: first, PET and PA6 chips are melted in the screw extruder respectively, and after metering, the first melt A (blue mark in the figure) and the second melt B (red mark in the figure) are obtained. The two melts are independently transported to the top of the assembled spinneret assembly. The first melt A enters the first annular flow channel 11, is distributed by the first flow guide groove 21, and then flows into the first annular material groove 31 of the third distribution plate 3 through the plurality of third through holes 23, and finally converges to the position of each boss 33 and flows out from the material passage 332. At the same time, the second melt B follows the same logic path (second annular flow channel 12→second flow guide groove 22→fourth through hole 24→second annular material groove 32), and finally reaches each boss 33 and is extruded in the form of a plurality of fine streams vertically downward from the discharge hole 331. Since the material passage 332 is laterally open, the outflow direction of the first melt A has a certain radial component.

[0066] In the narrow space between the lower end face of the boss 33 and the inlet of the spinneret hole 41, the vertically downward fine stream of the second melt B from the discharge hole 331 meets the slightly inclined fine stream of the first melt A from the material passage 332. Since they are physically forced to be arranged at intervals on the circumference, no large-scale mixing occurs here, but an initial composite interface is immediately formed in a spatially alternating and spaced manner. Subsequently, this group of melt beams with a preliminary pattern is jointly extruded into the spinneret hole 41 below under the action of pressure. Under the shearing flow and stretching action of the spinneret hole 41, the melt interface is further trimmed and solidified, and finally after being extruded from the spinneret hole 41, it is cooled and solidified by side blowing to form an orange petal-shaped composite fiber with a cross-sectional structure as shown in Figure 10 The cross-sectional structure of the fiber is shown in the figure. In the cross section of the fiber, the PET component (A) and the PA6 component (B) are clearly and regularly arranged alternately like petals, and the interface is clear.

[0067] In order to obtain the final commercial ultrafine fiber product, subsequent processing of the above nascent fiber is also required. The orange petal-shaped composite fiber filament wound is subjected to high-pressure water jet treatment by a mechanical water jet machine, or is woven into cloth and then treated in an alkali solution (PA6 is alkali-resistant while PET is not resistant to strong alkali). During the treatment process, the bonding interface between the two components is destroyed under the action of mechanical force or chemical action, and the whole composite fiber is broken into a number of times of single-component (PET or PA6) ultrafine fiber hetero-single filaments, forming a fluffy and soft fiber web. This fiber opening step is a key link for realizing the value of the technical solution.

[0068] Technical effect verification: By adopting the spinneret assembly and method of the present application, the following positive effects can be verified: 1) High yarn stability: due to the pre-arrangement effect of the boss structure, the random co-current of the melt at the spinneret hole entrance is completely avoided, and the spinning process breakage rate is significantly reduced. 2) Excellent fiber cross-section uniformity: under a microscope, the consistency of the number, shape and size of the orange petals of the fibers produced by different spinneret holes is more than 95%, which is much better than the traditional distribution method. 3) Improved fiber opening efficiency and quality: the regular and clear interface makes subsequent water jet or alkali reduction opening easier and more complete, the uniformity of the obtained ultra-fine fiber bundle is improved, the residual unsplit "hard points" are reduced, and the softness and hand feeling of the final product are substantially improved.

[0069] The above only describes the preferred embodiment of the present application, which describes the specific case of taking PET as the first component, PA6 as the second component, and forming an 8-petal structure. Those skilled in the art can make various modifications under the inspiration of the concept of the present application. For example, the materials of the first component and the second component can be interchanged, or other polymer combinations (such as PET / PP, PA / PE, etc.) can be used; the number of orange petals can be flexibly adjusted to 4, 6, 10 or 16, etc. by increasing or decreasing the number of small holes and small grooves on the boss; the number of annular collection grooves on the third distribution plate can also be increased according to product design needs. Any technical solution that adopts the same or similar fluid pre-arrangement logic as the present design, forces the formation of spaced parallel melt flow through upstream structure, and then composite spinning, should fall within the protection scope of the claims of the present application.

Claims

1. A segment-shaped composite fiber spinneret assembly, characterized in that, It comprises a first distribution plate (1), a second distribution plate (2), a third distribution plate (3) and a spinneret (4) which are stacked from top to bottom and are in fluid communication; The first distribution plate (1) is provided with a first annular flow channel (11) and a second annular flow channel (12) which are isolated from each other and are used for receiving and distributing the first melt (A) and the second melt (B) respectively; a plurality of first through holes (13) and second through holes (14) are arranged in the first annular flow channel (11) and the second annular flow channel (12) respectively and penetrate the first distribution plate (1); The upper surface of the second distribution plate (2) is provided with a plurality of first flow guide grooves (21) and second flow guide grooves (22) at positions corresponding to the first through holes (13) and the second through holes (14) respectively, and the lower surface is provided with a plurality of third through holes (23) and fourth through holes (24) which are in communication with the first flow guide grooves (21) and the second flow guide grooves (22) respectively and guide the melt downward; The upper surface of the third distribution plate (3) is provided with at least one circle of first annular material grooves (31) and at least one circle of second annular material grooves (32) which are spaced apart from each other at positions corresponding to the third through holes (23) and the fourth through holes (24); the lower surface of the third distribution plate (3) is provided with a boss (33) which protrudes downward, the boss (33) is provided with a plurality of discharge holes (331) which are in communication with the second annular material grooves (32) and a plurality of material passing grooves (332) which are in communication with the first annular material grooves (31), and the discharge holes (331) and the material passing grooves (332) are arranged alternately and spaced apart at the lower end surface of the boss (33); The spinneret (4) is provided with a spinneret hole (41), and the lower end of the boss (33) extends into the upper part of the spinneret hole (41), so that the second melt (B) and the first melt (A) from the discharge holes (331) and the material passing grooves (332) converge in the spinneret hole (41) in a spaced parallel form and are extruded.

2. The orange segment composite fiber spinneret assembly according to claim 1, wherein The first annular flow channel (11) and the second annular flow channel (12) on the first distribution plate (1) are concentric annular grooves, and the diameter of the second annular flow channel (12) is greater than the diameter of the first annular flow channel (11).

3. The orange segment composite fiber spinneret assembly of claim 1, wherein The first flow guide grooves (21) and the second flow guide grooves (22) on the second distribution plate (2) are strip grooves extending in the radial direction, and the length of the first flow guide grooves (21) is greater than the length of the second flow guide grooves (22).

4. The orange segment composite fiber spinneret assembly of claim 1, wherein The third distribution plate (3) is provided with N+1 circles of first annular material grooves (31) and N circles of second annular material grooves (32), and the second annular material grooves (32) are located between two circles of the first annular material grooves (31), wherein N≥1, and all the annular material grooves are concentrically distributed along the radial direction of the third distribution plate.

5. The orange segment composite fiber spinneret assembly of claim 1, wherein The material passing grooves (332) are grooves which are opened on the side surface of the boss (33) and extend to the lower end surface thereof, and the discharge holes (331) are vertical micro-holes which penetrate the boss (33).

6. The orange segment composite fiber spinneret assembly according to any one of claims 1 to 5, characterized in that The number of the discharge holes (331) and the material passing grooves (332) is 4-12, and they are uniformly and alternately arranged.

7. A method for producing a segmented pie composite fiber, characterized by comprising: The application discloses a spinning plate assembly and a preparation method thereof. S1: melt the first polymer and the second polymer respectively to obtain a first melt (A) and a second melt (B); S2: independently introduce the first melt (A) and the second melt (B) into a first annular flow channel (11) and a second annular flow channel (12) of a first distribution plate (1) of the spinning plate assembly respectively; the first melt (A) and the second melt (B) flow out through the first through hole (13) and the second through hole (14) respectively and correspondingly flow into a first flow guide groove (21) and a second flow guide groove (22) on the second distribution plate (2); S3: after the two melts are distributed by the second distribution plate (2), the two melts enter a first annular material groove (31) and a second annular material groove (32) on the third distribution plate (3) respectively; S4: the first melt (A) flows out through the material passing groove (332) on the boss (33), the second melt (B) flows out through the material outlet hole (331) on the boss (33), and the two melts are compounded in a preset interval and parallel mode at an inlet of a spinning hole (41) of the spinning plate (4); S5: the compounded melt flows through the spinning hole (41) and is extruded, cooled and solidified to form an orange petal-shaped composite fiber.

8. The preparation method according to claim 7, characterized in that, The first polymer is polyethylene terephthalate (PET), and the second polymer is polyamide 6 (PA6) or polyamide 66 (PA66).

9. The preparation method according to claim 7, characterized in that, In step S5, the extruded nascent fiber is subjected to a cooling, oiling, drafting and winding process to obtain an orange petal-shaped composite fiber filament.

10. The preparation method according to claim 7, characterized in that, The application further comprises a step S6 of performing an opening treatment on the orange petal-shaped composite fiber obtained in step S5, wherein the opening treatment is mechanical water jetting treatment or chemical alkali weight reduction treatment, so that the interval and parallel interface of the first melt (A) and the second melt (B) is separated, and an ultrafine fiber bundle is obtained.

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