An apparatus and method for preparing multi-shaped composite fibers

Abstract

This invention belongs to the field of chemical fiber textile technology and discloses a preparation device and method for multi-shaped composite fibers. The preparation device includes a cooling duct, a component shell, and a top cover, a self-sealing gasket, a flow divider, a sand cup, and a spinneret, all arranged from top to bottom within the component shell. The spinneret has three types of spinnerets: C-shaped, triangular, and fan-shaped. The C-shaped spinnerets have an arc-shaped outlet, the triangular spinnerets have an equilateral triangle-shaped outlet, and the fan-shaped spinnerets have an outlet composed of three arcs, with one end of each arc intersecting at a point. The spinnerets are located in a lens-shaped area on the spinneret. The preparation method for the multi-shaped composite fibers is as follows: polyester melt extrusion → cooling and forming → bundling and oiling → winding and forming. This invention solves the problems of uneven cooling, high evenness CV value, and low shapeability of multi-shaped composite fibers, maintaining a high level of shapeability between the inner and outer fibers.

Description

Technical Field

[0001] This invention belongs to the field of chemical fiber textile technology, and relates to a preparation device and method for multi-shaped composite fibers. Background Technology

[0002] In the field of chemical fiber textiles, profiled fibers, due to their unique cross-sectional shapes, endow fabrics with special hand feel, luster, bulkiness, and anti-pilling properties, attracting widespread attention and application. As a key component in the production of profiled fibers, the spinneret's spinneret orifice shape and layout directly determine the fiber's cross-sectional morphology and properties. However, current spinneret designs for profiled fiber production have many flaws, severely restricting the improvement of profiled fiber performance and production quality.

[0003] From the perspective of spinneret design, traditional spinnerets have extremely limited spinneret orifice shapes, mostly confined to circular or simple geometric shapes. This simplistic design struggles to meet the market's growing demand for diverse, high-performance profiled fibers. Even when some spinnerets feature multiple profiled orifices, there are significant shortcomings in the orifice shape parameter design. During melt extrusion, the melt expansion effect is not fully considered, resulting in an actual cross-sectional shape of the extruded fiber that deviates considerably from the design target. This deviation not only affects the fiber's functionality but also reduces its appearance quality. Particularly in the production of profiled fibers with hollow structures, an unreasonable spinneret orifice shape design can lead to instability in the hollow structure. For example, hollow fibers may experience gap closure, forming a closed structure, or the internal support structure may not mesh well with the hollow portion, resulting in a significant decrease in the fiber's mechanical properties.

[0004] In terms of spinneret layout, existing spinnerets lack systematic planning. The spinnerets are distributed arbitrarily, without fully considering the uniformity of melt flow and the synergistic effect between fibers with different orifice types. This unreasonable layout directly reduces fiber production efficiency and easily causes turbulent melt flow within the spinneret. The end result is that the quality of fibers extruded from each spinneret is inconsistent, failing to meet the stringent production requirements of high-quality textiles.

[0005] For the production of multi-shaped composite fibers, the shortcomings of existing technologies are even more pronounced. Taking patent CN 108823658 A as an example, although it produced double-shaped fibers with a shape accuracy of 52% by improving the process and designing the spinneret, it used the same annular uniform distribution method on the spinneret as the round-hole filaments, failing to consider the temperature sensitivity differences of monofilaments with different specific surface areas. This leads to uneven filament cooling, high thermal stress CV value, high evenness CV value, low full winding rate, and even difficulty in achieving mass production. In addition, in the actual production process, because the melt flow rate and pressure extruded from spinnerets of different shapes are difficult to control precisely, the proportion and distribution between the components of the composite fiber are difficult to achieve an ideal state, seriously affecting the stability of the overall fiber performance.

[0006] In terms of breathability and moisture wicking performance, existing spinneret designs cannot effectively create fiber structures that facilitate air circulation and moisture removal. Most fibers produced by spinnerets have an unreasonable internal pore structure, failing to form continuous air channels, resulting in poor breathability. Simultaneously, the fiber surface morphology is not conducive to the rapid transfer and evaporation of moisture, making it easy to feel stuffy and hot during wear or use, failing to meet people's needs for comfort.

[0007] In terms of abrasion resistance, fibers produced by traditional spinnerets are prone to surface wear and fuzzing due to their unreasonable cross-sectional structure design when subjected to friction. The fiber surface lacks an effective protective structure and cannot resist the damage caused by external friction, thus shortening the service life of fiber products and limiting their application in scenarios requiring frequent friction.

[0008] Given the shortcomings in the design and layout of the spinneret holes and the production of multi-shaped composite fibers, there is an urgent need to develop a new spinneret design scheme to manufacture shaped fibers that maintain a high degree of irregularity while possessing good morphological stability, wear resistance, and excellent breathability and moisture-wicking function, so as to meet the market's urgent demand for high-performance fiber materials. Summary of the Invention

[0009] The purpose of this invention is to solve the problems existing in the prior art and to provide a preparation device and method for multi-shaped composite fibers.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A device for preparing multi-shaped composite fibers includes a cooling duct, a component shell, and a top cover, a self-sealing gasket, a flow divider, a sand cup, and a spinneret, which are located inside the component shell and arranged from top to bottom. The top cover is provided with a melt inlet hole, and the spinneret is provided with spinneret holes. There are three types of spinneret holes: C-type spinneret holes, triangular spinneret holes, and fan blade type spinneret holes.

[0012] The exit shape of the C-type spinneret is an arc with a central angle of 90-93°. This is mainly based on the consideration of the melt extrusion expansion effect. If the central angle is too small, the triangular fiber is easy to detach from the inner cavity structure of the C-type fiber. If the central angle is too large, the C-type notch is easy to close to form a closed hollow fiber. The diameter of the circle corresponding to this arc is 0.35-0.5mm.

[0013] The outlet shape of the triangular spinneret is an equilateral triangle because equilateral triangles have good mutual support properties. This shape is not easily deformed and can stably support C-shaped hollow fibers. The side length of the equilateral triangle is 0.1-0.15mm.

[0014] The outlet shape of the fan-shaped spinneret is composed of three arcs, one end of which intersects at a point. The outlet shape of the fan-shaped spinneret remains unchanged when rotated 120°, 240° or 360° around this point. The central angle of each arc is 150-180°, and the diameter of the circle corresponding to each arc is 0.12-0.18mm.

[0015] The number of C-type spinnerets and triangular spinnerets is the same, and they correspond one-to-one. The triangular spinnerets are located inside the corresponding C-type spinnerets, and the centers of their outlet shapes coincide. One vertex of the outlet shape of the triangular spinneret is directly opposite the opening of the outlet shape of the C-type spinneret.

[0016] The spinneret has two symmetrical and spaced-apart lens-shaped areas, which are formed by an inner arc and an outer arc. The inner and outer arcs are curved in opposite directions, and the outer arc coincides with the edge of the spinneret.

[0017] All spinnerets are located within the lens-shaped area. Within each lens-shaped area, C-shaped spinnerets are arranged along the outer arc spacing with their openings facing the outer arc, while fan-shaped spinnerets are arranged along the inner arc spacing. This layout is primarily based on the following considerations: fan-shaped fibers have higher anisotropy and require faster cooling, hence their placement in the inner ring; while the C-shaped and triangular spinnerets combine to form a hollow triangular structure, which is placed in the outer ring. Functionally, the C-shaped structure acts like a "clothing," ensuring the fiber has good abrasion resistance; the triangular structure acts like a "bone," ensuring fiber shape stability and preventing deformation; and the fan-shaped structure acts like a "frame," helping to maintain the fiber's fluffiness and providing excellent breathability and moisture wicking performance.

[0018] As a preferred technical solution:

[0019] As described above, in the apparatus for preparing multi-shaped composite fibers, an electric heating tube is provided inside the region (with a symmetrical axe shape) between two lens-shaped regions on the spinneret. The electric heating tube is laid along the inner arc of the lens-shaped region. The minimum distance between the electric heating tube and each fan-shaped spinneret hole is the same. The minimum distance between the electric heating tube and the C-shaped spinneret hole is greater than the minimum distance between the electric heating tube and each fan-shaped spinneret hole.

[0020] The electric heating tube possesses highly efficient heating performance, significantly increasing the melt temperature of the inner ring of the spinneret. Given the large specific surface area of ​​highly shaped fibers, which suffer from rapid heat dissipation and significant heat loss, the electric heating tube is installed close to the fan-shaped spinneret orifice. This timely compensation compensates for heat loss caused by the spinneret being exposed to air, thereby maintaining good melt flowability of the inner ring of highly shaped fibers and ensuring the quality of melt extrusion. In this way, the resulting fibers exhibit high breaking strength and elongation at break. Simultaneously, the electric heating tube also helps compensate for the temperature drop on the spinneret surface caused by cooling air. The electric heating tube of this invention ensures uniform and stable heating of the inner ring fibers, maintaining good melt flowability, facilitating smooth melt extrusion, reducing elastic swelling during extrusion, and improving fiber shapedness. In actual production, it effectively avoids nozzle problems, reduces the breakage rate of multi-shaped composite fibers, and consistently maintains high fiber shapedness.

[0021] As described above, in a multi-shaped composite fiber preparation device, the area between two lens-shaped regions on the spinneret is divided into upper and lower layers. The electric heating tube is located in the lower layer, and each of the four corners of the lower layer has a through hole, which are symmetrical in pairs.

[0022] As described above, in a multi-shaped composite fiber preparation device, the upper surface of the spinneret is provided with an elliptical annular groove and a circular annular groove, the centers of the elliptical annular groove and the circular annular groove coincide with the center of the spinneret, and the elliptical annular groove is surrounded by the circular annular groove.

[0023] The fan-shaped spinneret is located within the area enclosed by the elliptical annular groove, while the C-shaped spinneret is located within the area enclosed by the elliptical annular groove and the circular annular groove.

[0024] The abrasive cup is located above the spinneret. Inside the abrasive cup are two arc-shaped vertical plates that together form an inner cavity. The two arc-shaped vertical plates and the abrasive cup respectively form two outer cavities. The bottom of both the inner and outer cavities are provided with through holes. The edge shape and size of the inner cavity are the same as the elliptical annular groove and are located directly above it. The edge shape and size of the abrasive cup are the same as the circular annular groove and are located directly above it.

[0025] Two annular sealing gaskets are sandwiched between the sand cup and the spinneret, located in an elliptical annular groove and a circular annular groove, respectively. This effectively prevents the melt from flowing from the sand cup to the spinneret orifice and causing leakage. The circular annular groove is used to prevent the melt flowing from the outer chamber to the C-type and triangular spinneret orifices from leaking out. The elliptical annular groove is used to prevent the melt from flowing from the inner chamber to the fan-shaped spinneret orifice into the C-type and triangular spinneret orifices, and at the same time, it can also prevent the melt flowing from the outer chamber to the C-type and triangular spinneret orifices from flowing into the fan-shaped spinneret orifice.

[0026] As described above, the apparatus for preparing multi-shaped composite fibers has 60-mesh metal sand and 50-mesh metal mesh placed inside the inner chamber to improve the melt filtration accuracy and increase the back pressure of the components, ensuring that the high-shape fibers maintain a high degree of shape during the extrusion molding process; and 40-mesh metal sand and 50-mesh metal mesh placed inside the outer chamber to reduce the extrusion pressure of the fibers and thus improve the breaking strength of the fibers.

[0027] Different fiber cross-sections impose different requirements on melt uniformity. In existing technologies, the internal cavity of the sand cup is a cylindrical structure (e.g., Figure 5 As shown, after the melt is mixed in the same abrasive cup cavity, it is directly extruded from spinnerets with different cross-sections. This method has obvious drawbacks. Since the same abrasive cup can only be filled with metal abrasive of the same specification, it cannot meet the different melt quality requirements of fibers with different cross-sections on the same spinneret. Taking this invention as an example, trilobal fibers require a more uniform melt, thus requiring higher filtration accuracy in the abrasive mix. In contrast, C-shaped and triangular fibers have relatively lower requirements for melt quality. The different requirements of different fibers are significant, and existing technologies cannot meet all these requirements simultaneously.

[0028] The present invention has an inner chamber and an outer chamber inside the sand cup, which can hold metal sand of different specifications respectively. Through differentiated sand distribution, the requirements of different cross-section fibers on component back pressure and melt filtration accuracy are accurately met, effectively solving the technical problem of uneven melt distribution.

[0029] As described above, the apparatus for preparing multi-shaped composite fibers has two symmetrically distributed feed ramps at the upper end of the inner chamber. The two feed ramps do not completely seal the upper end of the inner chamber. The feed ramps are lower as they approach the center of the inner chamber. The slope of the feed ramps (referring to the ratio of the height of the inner wall of the sand cup to the distance from the inner wall of the sand cup to the edge of the fan-shaped spinneret) is 1:2-3. Such a slope can ensure that the melt has good fluidity while avoiding slight degradation caused by excessive heat preservation time, thereby ensuring stable melt quality.

[0030] As described above, the apparatus for preparing multi-shaped composite fibers comprises a flow divider consisting of a frustum and multiple trapezoidal teeth. The frustum is located above two arc-shaped vertical plates and is coaxial with the sand cup. The upper end of the frustum is located directly below the melt inlet hole. All the trapezoidal teeth are clamped between the inner wall of the sand cup and the bottom of the frustum. All the trapezoidal teeth are fixedly connected to the bottom of the frustum and are evenly distributed around the central axis of the frustum. The gap between the bottom of two adjacent trapezoidal teeth is 1-2 mm. Part of the gap between all the trapezoidal teeth is located above the outer chamber, and the other part is located above the inner chamber.

[0031] The trapezoidal teeth create evenly distributed channels between the manifold and the inner wall of the assembly. This structure provides a flow path for the melt and positions the manifold by adhering to the inner wall of the assembly. The melt inlet is concentrically positioned with the manifold. The melt first passes through the frustum and then disperses circumferentially into the sand cup. Because the distance the melt travels to different spinnerets after entering the sand cup varies, the holding time also differs. Specifically, the melt travels a longer path to the highly irregular fan-shaped spinnerets, resulting in a correspondingly longer holding time. This makes the extrusion process smoother and effectively delays the tendency of the fiber cross-section to become round under the expansion effect, maintaining the high irregularity of the fiber. Meanwhile, the outer ring spinnerets are closer to the inlet, resulting in a shorter melt holding time. At the same draw ratio, the fiber's breaking elongation decreases, its breaking strength increases, and the formed fiber exhibits better abrasion resistance.

[0032] As described above, the apparatus for preparing multi-shaped composite fibers includes a self-sealing gasket composed of a frustum cylinder and an inverted frustum cylinder. Both the frustum cylinder and the inverted frustum cylinder are open at both ends. The inverted frustum cylinder is fitted onto the frustum cylinder, and its lower edge is connected to the lower edge of the frustum cylinder. The height of the inverted frustum cylinder is lower than that of the frustum cylinder. An annular sealing groove is provided on the inner wall of the sand cup. The inner diameter of the annular sealing groove is 0.5-1 mm smaller than the outer diameter of the upper end of the inverted frustum cylinder. The upper edge of the inverted frustum cylinder is inserted into the annular sealing groove. A cylindrical protrusion is provided at the bottom of the top cover. The melt inlet hole passes through the cylindrical protrusion and is coaxial with it. The upper edge of the frustum cylinder is fitted onto the cylindrical protrusion. The self-sealing gasket is supported by a flow divider plate.

[0033] In existing technologies, to ensure high fiber profile and smooth fiber extrusion, it is necessary to appropriately increase the module back pressure. However, higher spinneret back pressure places higher demands on the module's sealing performance. In existing technologies, the module housing does not have a sealing groove; the seal relies solely on the radial seal formed by the gasket's contact with the inner wall of the module housing. When the melt is impacted by the module back pressure from the spinneret, it will impact the self-sealing gasket in the opposite direction (i.e., towards the feed inlet). Because the self-sealing gasket in existing technologies has a frustum-shaped structure (…),… Figure 2 As shown in (b) and (d), the seal between the bottom outer wall and the inner wall of the module housing can only be achieved through radial force. However, the melt also generates an upward axial force, which prevents the self-sealing gasket from adhering tightly to the inner wall of the module, thus creating an internal leakage point. Therefore, while the self-sealing gasket under current technology mainly solves the problem of external leakage of the module, it cannot solve the problem of internal leakage caused by higher pressure. Internal leakage will cause unstable pressure differentials between the individual filaments and unstable melt flow, making the filaments prone to breakage.

[0034] In this invention, to ensure smooth extrusion molding of multi-shaped composite fibers and maintain a high degree of irregularity, the back pressure of the component is set to 180-200 bar. The self-sealing gasket in this invention ( Figure 2The cross-section shown in (a) and (c) is W-shaped, and the installation method is from top to bottom. During installation, the upper end of the inverted frustum is compressed by inward force and stores elasticity. When the upper edge of the inverted frustum is inserted into the annular sealing groove, the compression force decreases, but because the outer diameter of the upper end of the inverted frustum is 0.5-1mm larger than the inner diameter of the annular sealing groove, the upper end of the inverted frustum will apply a pre-tightening force to the annular sealing groove under the action of elasticity, ensuring that the two fit tightly. When the melt is input, the self-sealing gasket is subjected to axial force under the pressure of the melt from bottom to top, and the upper end of the inverted frustum deforms and is stuck in the annular sealing groove, increasing the contact area with the annular sealing groove and forming a tighter sealing surface, effectively preventing the melt from leaking backward, and thus constructing a closed chamber between the two, ensuring that the melt is uniformly mixed in the final sealed chamber. In this way, the annular sealing groove and the self-sealing gasket form a labyrinth-like leak-proof structure. At the same time, with the help of the reaction pressure of the melt, a dual sealing effect in the radial and axial directions is achieved, which solves the problem of high internal pressure and excessive slurry leakage in the production of multi-shaped composite fibers.

[0035] The apparatus for preparing multi-shaped composite fibers as described above includes a cooling duct composed of two arc-shaped rectifier plates I, two arc-shaped rectifier plates II, and two arc plates.

[0036] The orthographic projections of the two arc-shaped rectifier plates I completely coincide with the orthographic projections of the outer arcs of the two lens-shaped regions, and the orthographic projections of the two arc-shaped rectifier plates II completely coincide with the orthographic projections of the inner arcs of the two lens-shaped regions. The two arc-shaped rectifier plates I are connected by the two arc-shaped plates to form a complete cylinder.

[0037] The number of rectifier holes in arc-shaped rectifier plate I is p, and the hole diameter is a; the number of rectifier holes in arc-shaped rectifier plate II is q, and the hole diameter is b; p<q,a> b.

[0038] Fibers with different cross-sections have different specific surface areas, therefore they need to be cooled separately to ensure high cooling uniformity among fibers with the same cross-section. On a spinneret, the spinneret orifices are distributed in concentric rings from the inside out. When using outer ring cooling, the cooling air passes through the fibers layer by layer from the outside in. This results in the fibers on the outer ring of the spinneret first coming into contact with the lower-temperature, higher-pressure cooling air, while the air used to cool the inner ring fibers carries away some of the heat from the outer ring fibers, significantly reducing the cooling effect. The situation is exactly the opposite with inner ring cooling.

[0039] The inner fibers targeted in this invention have a large specific surface area, resulting in rapid heat dissipation and high heat exchange efficiency. They require rapid cooling to maintain high shape accuracy while avoiding over-cooling due to excessive airflow, which could reduce fiber breaking strength. However, existing external and internal ring-blowing cooling methods fail to meet this requirement. With external ring-blowing, the cooling airflow reaches the inner fibers at insufficient speed; to meet the cooling speed of the inner fibers, the airflow velocity towards the outer fibers would be too high, causing fiber movement, adhesion, and increased evenness CV value. While internal ring-blowing can meet the cooling conditions for the inner fibers, the outer fibers cannot be sufficiently cooled, leading to adhesion and increased evenness CV value.

[0040] To address the aforementioned issues, this invention optimizes the design of the cooling duct, where arc-shaped rectifier plate I exhibits low wind resistance, while arc-shaped rectifier plate II exhibits high wind resistance. When cooling air is circumferentially blown around the multi-arc cooling duct, the outer fibers receive a larger airflow due to the airflow guidance from the cooling duct and the rectification effect of the rectifier plates. However, due to the large diameter 'a' of the rectifier holes, the wind speed is relatively low. The inner fibers receive a smaller airflow, but the smaller diameter 'b' of the rectifier holes results in a strong rectification effect and a high wind speed. The cooling air is blown towards the fibers in a laminar flow state. The inner fibers, due to their large specific surface area, can cool and solidify rapidly while maintaining high shape accuracy, without over-cooling. This differentiated cooling method significantly improves the cooling uniformity of fibers with different cross-sections, maintains high shape accuracy in the inner fibers, increases the breaking elongation and breaking strength of the outer fibers, and enhances their wear resistance.

[0041] The present invention also provides a method for preparing multi-shaped composite fibers, using a multi-shaped composite fiber preparation apparatus as described in any of the preceding claims.

[0042] As a preferred technical solution:

[0043] The preparation method of the multi-shaped composite fiber described above includes the following process flow: polyester melt extrusion → cooling and forming → bundling and oiling → winding and forming.

[0044] The process parameters include: module back pressure 180-200 bar, spinneret extrusion temperature 295-296℃, cooling air temperature 19-22℃, air humidity 80-85%, air pressure 15-19 Pa, oil content 0.35-0.45%, and winding speed 2650-2800 m / min.

[0045] The method for preparing a multi-shaped composite fiber as described above has the following specifications: the multi-shaped composite fiber has a specification of 22-33 dtex / 16-24f, a breaking elongation CV value of 1.64-2.16%, a yarn unevenness CV value of 0.78-0.85%, and a full roll rate of 99.1-99.5%.

[0046] Beneficial effects:

[0047] The multi-shaped composite fiber preparation device of the present invention systematically solves traditional production problems through a number of innovative designs and significantly improves product performance.

[0048] The spinneret of this invention features three types of spinneret holes: C-shaped, triangular, and fan-shaped, with optimized design. This results in multi-shaped composite fibers with stable morphology, good wear resistance, and excellent air permeability and moisture wicking performance. Simultaneously, the electric heating tube inside the spinneret ensures uniform and stable heating of the inner fibers, resulting in good melt flow and smooth melt extrusion. This reduces elastic swelling during extrusion, thereby improving fiber shape and avoiding head-filling problems in actual production, reducing the breakage rate of multi-shaped composite fibers, and maintaining high fiber shape throughout production.

[0049] The sand cup of this invention can hold metal sand of different specifications. Through differentiated sand distribution, it can accurately meet the requirements of different cross-section fibers for component back pressure and melt filtration accuracy, effectively solving the technical problem of uneven melt distribution.

[0050] The annular sealing groove and self-sealing gasket of this invention form a labyrinth-type leak-proof structure. At the same time, with the help of the reaction pressure of the melt, a dual sealing effect in the radial and axial directions is achieved, which solves the problem of high internal pressure and excessive slurry leakage in the production of multi-shaped composite fibers.

[0051] The cooling duct of the present invention adopts a differentiated cooling design, which significantly improves the cooling uniformity of fibers with different cross-sections, keeps the inner ring fibers with high irregularity, and at the same time improves the breaking elongation and breaking strength of the outer ring fibers, thereby enhancing the wear resistance of the outer ring fibers.

[0052] In summary, the multi-shaped composite fiber preparation device of the present invention, through the above-mentioned innovative designs, completely solves the problems of uneven cooling, large CV value of yarn evenness, and low irregularity of multi-shaped composite fibers, so as to maintain a high level of irregularity of inner and outer fibers and consistent breaking strength, and finally achieve a high-quality production effect with low CV value of yarn evenness and high irregularity of fibers. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the apparatus for preparing multi-shaped composite fibers according to the present invention;

[0054] Figure 2 The figures are schematic diagrams of the self-sealing gasket of the present invention and the self-sealing gasket of the prior art; in the figures, (a) is a cross-sectional view of the self-sealing gasket of the present invention, (b) is a cross-sectional view of the self-sealing gasket of the prior art, (c) is a structural schematic diagram of the self-sealing gasket of the present invention, and (d) is a structural schematic diagram of the self-sealing gasket of the prior art.

[0055] Figure 3 This is a schematic diagram of the structure of the flow divider of the present invention;

[0056] Figure 4 This is a schematic diagram of the structure of the sand cup of the present invention;

[0057] Figure 5 This is a schematic diagram of the structure of a sand cup in the prior art;

[0058] Figure 6 This is a schematic diagram of the spinneret and electric heating tube of the present invention; in the figure, (a) is the front view of the spinneret, (b) is the cross-sectional view of the electric heating tube, (c) is a schematic diagram of the position of the spinneret and the electric heating tube (BB indicates that Figure (c) is cut open as shown by the arrows B and B in Figure (a), and (d) is a schematic diagram of the assembly of the spinneret and the electric heating tube.

[0059] Figure 7 This is a schematic diagram of the cooling duct and the cooling of the filaments according to the present invention; in the figure, (a) is a schematic diagram of the structure of the cooling duct, and (b) is a schematic diagram of the cooling of the filaments. The black arrow in figure (b) indicates the direction of the cooling airflow.

[0060] Among them, 1.1-diverter plate, 1.11-frustum, 1.12-trapezoidal teeth, 1.2-self-sealing gasket, 1.3-component shell, 1.31-annular sealing groove, 1.4-sand cup, 1.41-feeding inclined plate, 1.42-inner chamber, 1.44-outer chamber, 1.6-top cover, 2-spinneret, 2.1-C-type spinneret hole, 2.2-triangular spinneret hole, 2.3-fan blade type spinneret hole, 2.4-elliptical annular groove, 2.5-circular annular groove, 3.2-electric heating tube, 3.3-through hole, 4-cooling air duct, 4.2-arc rectifier plate I, 4.3-arc rectifier plate II, 4.4-arc plate. Detailed Implementation

[0061] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0062] The test methods for the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0063] Elongation at break (CV): The multi-shaped composite fibers prepared in each example were used as samples. Then, in accordance with the GB / T 8960-2015 standard "Polyester drawn yarn", the samples were stretched to break using a Swiss USTER-IV tensile tester under uniform tension at a constant speed. The elongation at break (CV) of the samples was obtained from the data displayed on the tensile tester.

[0064] Evenness coefficient (CV): The multi-shaped composite fibers prepared in each embodiment were used as samples. Then, in accordance with the GB / T 8960-2015 standard "Polyester Drawn Yarn", the samples were tested using a Swiss USTER-IV evenness tester. When the sample passed through the air capacitor composed of two parallel metal plates at the detection point, the capacitance changed accordingly due to the change in the weight per unit length of the sample. The rate of change of capacitance was linearly related to the change in the weight of the sample between the plates of the detection capacitor. The unevenness was then displayed by an automatic integrator, thus obtaining the evenness coefficient of the sample.

[0065] Breaking strength: The multi-shaped composite fibers prepared in each embodiment were used as samples. Then, in accordance with the standard GB / T14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments", the samples were stretched to the point of fracture using a Swiss USTER-IV tensile tester under uniform tension at a constant speed. The breaking strength of the samples was obtained from the data. The clamping distance was 250 mm and the tensile speed was 500 m / min.

[0066] Elongation at break: The multi-shaped composite fibers prepared in each embodiment were used as samples. Then, in accordance with the standard GB / T14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments", the samples were stretched to break using a Swiss USTER-IV tensile tester under uniform tension at a constant speed. The elongation at break of the samples was obtained from the data. The clamping distance was 250 mm and the stretching speed was 500 m / min.

[0067] Shapeness: The multi-shaped composite fibers prepared in each embodiment were used as samples, and the shapeness of the samples was tested in accordance with the FZ-T5002-2013 standard "Test Method for Shapeness of Chemical Fibers".

[0068] Example 1

[0069] An apparatus for preparing multi-shaped composite fibers, such as Figures 1-7 As shown, it includes a cooling duct 4, a component housing 1.3, and a top cover 1.6, a self-sealing gasket 1.2, a flow divider 1.1, a sand cup 1.4, and a spinneret 2, which are located inside the component housing 1.3 and arranged from top to bottom.

[0070] like Figure 6 As shown, the spinneret 2 is provided with three types of spinneret holes, namely C-type spinneret hole 2.1, triangular spinneret hole 2.2, and fan-shaped spinneret hole 2.3;

[0071] The outlet shape of the C-type spinneret 2.1 is an arc, the central angle of which is 90-93°, and the diameter of the circle corresponding to which the arc is 0.35-0.5mm;

[0072] The outlet shape of the triangular spinneret 2.2 is an equilateral triangle with a side length of 0.1-0.15 mm.

[0073] The outlet shape of the fan-shaped spinneret 2.3 is composed of 3 arcs, one end of which intersects at a point. The outlet shape of the fan-shaped spinneret 2.3 remains unchanged when rotated 120°, 240° or 360° around this point. The central angle of each arc is 150-180°, and the diameter of the circle corresponding to each arc is 0.12-0.18mm.

[0074] The number of C-type spinnerets 2.1 and triangular spinnerets 2.2 is the same, and they correspond one-to-one. The triangular spinneret 2.2 is located inside the corresponding C-type spinneret 2.1 and the center of their outlet shapes coincides. One vertex of the outlet shape of the triangular spinneret 2.2 is directly opposite the opening of the outlet shape of the C-type spinneret 2.1.

[0075] The spinneret 2 has two symmetrical and spaced-apart lens-shaped regions. The lens-shaped regions are surrounded by an inner arc and an outer arc. The inner arc and the outer arc have opposite bending directions, and the outer arc coincides with the edge of the spinneret 2.

[0076] All spinnerets are located within the lens-shaped area; within each lens-shaped area, C-type spinnerets 2.1 are arranged along the outer arc spacing and open towards the outer arc, while fan-shaped spinnerets 2.3 are arranged along the inner arc spacing.

[0077] The area between the two lens-shaped regions on the spinneret 2 is divided into upper and lower layers;

[0078] The electric heating tube 3.2 is located in the lower layer. The electric heating tube 3.2 is laid along the inner arc of the lens-shaped area. The minimum distance between the electric heating tube 3.2 and each fan blade type spinneret 2.3 is the same. The minimum distance between the electric heating tube 3.2 and the C-type spinneret 2.1 is greater than the minimum distance between the electric heating tube 3.2 and each fan blade type spinneret 2.3.

[0079] Each of the four corners of the lower layer has a through hole 3.3;

[0080] The upper surface of the spinneret 2 is provided with an elliptical annular groove 2.4 and a circular annular groove 2.5. The centers of the elliptical annular groove 2.4 and the circular annular groove 2.5 coincide with the center of the spinneret 2. The elliptical annular groove 2.4 is surrounded by the circular annular groove 2.5.

[0081] The fan-shaped spinneret 2.3 is located within the area enclosed by the elliptical annular groove 2.4, and the C-shaped spinneret 2.1 is located within the area enclosed by the elliptical annular groove 2.4 and the circular annular groove 2.5.

[0082] like Figure 1 , Figure 4As shown, the abrasive cup 1.4 is located above the spinneret 2. The interior of the abrasive cup 1.4 is provided with two arc-shaped vertical plates, which together form an inner cavity 1.42. The two arc-shaped vertical plates and the abrasive cup 1.4 respectively form two outer cavities 1.44. The bottom of both the inner cavity 1.42 and the outer cavity 1.44 are provided with through holes. The edge shape and size of the inner cavity 1.42 are the same as those of the elliptical annular groove 2.4 and are located directly above it. The edge shape and size of the abrasive cup 1.4 are the same as those of the circular annular groove 2.5 and are located directly above it.

[0083] Two annular sealing gaskets are sandwiched between the sand cup 1.4 and the spinneret 2, and are located in the elliptical annular groove 2.4 and the circular annular groove 2.5, respectively.

[0084] The upper end of the inner chamber 1.42 is provided with two symmetrically distributed feed ramps 1.41. The two feed ramps 1.41 do not completely seal the upper end of the inner chamber 1.42. The feed ramps 1.41 are lower as they are closer to the center of the inner chamber 1.42. The slope of the feed ramps 1.41 is 1:2-3.

[0085] The inner chamber 1.42 is filled with 60-mesh metal sand and 50-mesh metal mesh, while the outer chamber 1.44 is filled with 40-mesh metal sand and 50-mesh metal mesh.

[0086] The inner wall of the sand cup 1.4 is provided with an annular sealing groove 1.31;

[0087] like Figure 1 , Figure 3 As shown, the flow divider 1.1 consists of a frustum 1.11 and multiple trapezoidal teeth 1.12. The frustum 1.11 is located above the two arc-shaped vertical plates and is coaxial with the sand cup 1.4. The upper end of the frustum 1.11 is located directly below the melt inlet hole. All the trapezoidal teeth 1.12 are clamped between the inner wall of the sand cup 1.4 and the bottom of the frustum 1.11. All the trapezoidal teeth 1.12 are fixedly connected to the bottom of the frustum 1.11 and are evenly distributed around the central axis of the frustum 1.11. The tooth root gap between two adjacent trapezoidal teeth 1.12 is 1-2 mm. Part of the tooth gap between all the trapezoidal teeth 1.12 is located above the outer chamber 1.44, and the other part is located above the inner chamber 1.42.

[0088] like Figure 2 (a) Figure 2 As shown in (c), the self-sealing gasket 1.2 is composed of a frustum cylinder and an inverted frustum cylinder. Both the frustum cylinder and the inverted frustum cylinder are open at both ends. The inverted frustum cylinder is fitted on the frustum cylinder. The lower edge of the inverted frustum cylinder is connected to the lower edge of the frustum cylinder. The height of the inverted frustum cylinder is lower than that of the frustum cylinder.

[0089] The inner diameter of the annular sealing groove 1.31 is 0.5-1mm smaller than the outer diameter of the upper end of the inverted frustum cylinder, and the upper edge of the inverted frustum cylinder is inserted into the annular sealing groove 1.31;

[0090] The self-sealing gasket 1.2 is supported by the flow divider 1.1;

[0091] The upper cover 1.6 is provided with a melt inlet hole, and the bottom of the upper cover 1.6 is provided with a cylindrical protrusion. The melt inlet hole passes through the cylindrical protrusion and is coaxial with it. The upper edge of the frustum cylinder is fitted onto the cylindrical protrusion.

[0092] like Figure 7 As shown in (a), the cooling duct 4 consists of two arc-shaped rectifier plates I 4.2, two arc-shaped rectifier plates II 4.3, and two arc-shaped plates 4.4;

[0093] The orthographic projections of the two arc-shaped rectifier plates I 4.2 completely coincide with the orthographic projections of the outer arcs of the two lens-shaped regions, and the orthographic projections of the two arc-shaped rectifier plates II 4.3 completely coincide with the orthographic projections of the inner arcs of the two lens-shaped regions. The two arc-shaped rectifier plates I 4.2 are connected by two arc-shaped plates 4.4 to form a complete cylinder.

[0094] The number of rectifier holes in arc-shaped rectifier plate I 4.2 is p, and the hole diameter is a; the number of rectifier holes in arc-shaped rectifier plate II 4.3 is q, and the hole diameter is b; p<q,a> b.

[0095] Example 2

[0096] A method for preparing multi-shaped composite fibers, using the preparation apparatus described in Example 1, is as follows:

[0097] Polyester melt (intrinsic viscosity 0.660 dl / g, end carboxyl group content 25 mol / t, diethylene glycol content 1.0 wt%) is extruded through a spinneret and then sequentially subjected to cooling, bundling and oiling, and winding processes (the direction of the cold airflow during cooling is as follows). Figure 7 As shown in (b), a multi-shaped composite fiber was prepared; wherein:

[0098] Preparation apparatus used: The outer diameter of the spinneret is 60 mm;

[0099] The number of C-type spinnerets is 10, and the number of fan-type spinnerets is 6;

[0100] The distance between two adjacent C-type spinnerets is 11mm, the distance between two adjacent triangular spinnerets is 11mm, and the distance between two adjacent fan-shaped spinnerets is 5mm.

[0101] The central angle of the arc is 90°, and the diameter of the circle corresponding to the arc is 0.35 mm; the side length of the equilateral triangle is 0.1 mm.

[0102] The three arcs intersect at one point. The outlet shape of the fan-shaped spinneret remains unchanged when rotated 120° around this point. The central angle of each arc is 150°, and the diameter of the circle corresponding to each arc is 0.12mm.

[0103] The slope of the feed ramp is 1:2;

[0104] The inner diameter of the annular sealing groove is 0.5 mm smaller than the outer diameter of the upper end of the inverted frustum cylinder;

[0105] The gap between the bases of two adjacent trapezoidal teeth is 1 mm, and the height of the trapezoidal teeth is 6 mm.

[0106] The arc-shaped rectifier plate I has 170 rectifier holes with a diameter of 1.5 mm; the arc-shaped rectifier plate II has 210 rectifier holes with a diameter of 1 mm.

[0107] The process parameters include: component back pressure 180 bar, spinneret extrusion temperature 295℃, cooling air temperature 19℃, air humidity 80%, air pressure 15 Pa, oil content 0.35%, winding speed 2650 m / min, winding machine is Barmag Wings 40T-1500 / 10 winding head, the concentration of the oiling agent is 9 wt% (made by mixing crude oil of model Dryfi HL165M with pure water), and network pressure 0.85 bar.

[0108] The final multi-shaped composite fiber has the following specifications: 22dtex / 16f, breaking elongation of 119.8%, breaking elongation CV value of 2.16%, breaking strength of 3.08cN / dtex, yarn unevenness CV value of 0.79%, full roll rate of 99.1%, and irregularity of 55%.

[0109] Example 3

[0110] A method for preparing multi-shaped composite fibers, using the preparation apparatus described in Example 1, is as follows:

[0111] Polyester melt (intrinsic viscosity 0.660 dl / g, end carboxyl group content 25 mol / t, diethylene glycol content 1.0 wt%) was extruded through a spinneret, and then subjected to cooling, bundling, oiling, and winding processes to prepare multi-shaped composite fibers; wherein:

[0112] Preparation apparatus used: The outer diameter of the spinneret is 60 mm;

[0113] The number of C-type spinnerets is 10, and the number of fan-type spinnerets is 8;

[0114] The distance between two adjacent C-type spinnerets is 11 mm, the distance between two adjacent triangular spinnerets is 11 mm, and the distance between two adjacent fan-shaped spinnerets is 8.2 mm.

[0115] The central angle of the arc is 91°, and the diameter of the circle corresponding to the arc is 0.42 mm; the side length of the equilateral triangle is 0.12 mm.

[0116] The three arcs intersect at one point. The outlet shape of the fan-shaped spinneret remains unchanged when rotated 240° around this point. The central angle of each arc is 165°, and the diameter of the circle corresponding to each arc is 0.15mm.

[0117] The slope of the feed ramp is 1:2.5;

[0118] The inner diameter of the annular sealing groove is 0.7 mm smaller than the outer diameter of the upper end of the inverted frustum cylinder;

[0119] The gap between the bases of two adjacent trapezoidal teeth is 1.5 mm, and the height of the trapezoidal teeth is 6 mm.

[0120] The arc-shaped rectifier plate I has 180 rectifier holes with a diameter of 1.5 mm; the arc-shaped rectifier plate II has 225 rectifier holes with a diameter of 1 mm.

[0121] The process parameters include: component back pressure 190 bar, spinneret extrusion temperature 296℃, cooling air temperature 21℃, air humidity 82%, air pressure 17 Pa, oil content 0.4%, winding speed 2730 m / min, winding machine is Barmag Wings 40T-1500 / 10 winding head, the concentration of the oiling agent is 9 wt% (made by mixing crude oil of model Dryfi HL165M with pure water), and network pressure 0.9 bar.

[0122] The final multi-shaped composite fiber has the following specifications: 25 dtex / 18f, breaking elongation of 118.5%, breaking elongation CV value of 1.81%, breaking strength of 3.13 cN / dtex, yarn unevenness CV value of 0.78%, full roll rate of 99.2%, and irregularity of 56%.

[0123] Example 4

[0124] A method for preparing multi-shaped composite fibers, using the preparation apparatus described in Example 1, is as follows:

[0125] Polyester melt (intrinsic viscosity 0.660 dl / g, end carboxyl group content 25 mol / t, diethylene glycol content 1.0 wt%) was extruded through a spinneret, and then subjected to cooling, bundling, oiling, and winding processes to prepare multi-shaped composite fibers; wherein:

[0126] Preparation apparatus used: The outer diameter of the spinneret is 60 mm;

[0127] The number of C-type spinnerets is 12, and the number of fan-type spinnerets is 8;

[0128] The spacing between two adjacent C-type spinnerets is 9.5 mm, the spacing between two adjacent triangular spinnerets is 9.5 mm, and the spacing between two adjacent fan-shaped spinnerets is 8.2 mm.

[0129] The central angle of the arc is 93°, and the diameter of the circle corresponding to the arc is 0.5 mm; the side length of the equilateral triangle is 0.15 mm.

[0130] The three arcs intersect at one point. The outlet shape of the fan-shaped spinneret remains unchanged when rotated 360° around this point. The central angle of each arc is 180°, and the diameter of the circle corresponding to each arc is 0.18mm.

[0131] The slope of the feed ramp is 1:3;

[0132] The inner diameter of the annular sealing groove is 1mm smaller than the outer diameter of the upper end of the inverted frustum cylinder;

[0133] The gap between the bases of two adjacent trapezoidal teeth is 2mm, and the height of the trapezoidal teeth is 6mm.

[0134] The arc-shaped rectifier plate I has 160 rectifier holes with a diameter of 1.5 mm; the arc-shaped rectifier plate II has 200 rectifier holes with a diameter of 1 mm.

[0135] The process parameters include: component back pressure 200 bar, spinneret extrusion temperature 296℃, cooling air temperature 22℃, air humidity 85%, air pressure 19 Pa, oil content 0.45%, winding speed 2680 m / min, winding machine is Barmag Wings 40T-1500 / 10 winding head, the concentration of the oiling agent is 9 wt% (made by mixing crude oil of model Dryfi HL165M with pure water), and network pressure 0.8 bar.

[0136] The final multi-shaped composite fiber has the following specifications: 25 dtex / 20f, breaking elongation of 120.6%, breaking elongation CV value of 2.05%, breaking strength of 3.18 cN / dtex, yarn unevenness CV value of 0.85%, full roll rate of 99.3%, and irregularity of 57%.

[0137] Example 5

[0138] A method for preparing multi-shaped composite fibers, using the preparation apparatus described in Example 1, is as follows:

[0139] Polyester melt (intrinsic viscosity 0.660 dl / g, end carboxyl group content 25 mol / t, diethylene glycol content 1.0 wt%) was extruded through a spinneret, and then subjected to cooling, bundling, oiling, and winding processes to prepare multi-shaped composite fibers; wherein:

[0140] Preparation apparatus used: The outer diameter of the spinneret is 60 mm;

[0141] The number of C-type spinnerets is 14, and the number of fan-type spinnerets is 8;

[0142] The spacing between two adjacent C-type spinnerets is 7.5 mm, the spacing between two adjacent triangular spinnerets is 7.5 mm, and the spacing between two adjacent fan-shaped spinnerets is 8.2 mm.

[0143] The central angle of the arc is 91.5°, and the diameter of the circle corresponding to the arc is 0.4 mm; the side length of the equilateral triangle is 0.13 mm.

[0144] The three arcs intersect at one point. The outlet shape of the fan-shaped spinneret remains unchanged when rotated 240° around this point. The central angle of each arc is 170°, and the diameter of the circle corresponding to each arc is 0.16mm.

[0145] The slope of the feed ramp is 1:2.5;

[0146] The inner diameter of the annular sealing groove is 0.8 mm smaller than the outer diameter of the upper end of the inverted frustum cylinder;

[0147] The gap between the bases of two adjacent trapezoidal teeth is 1.5 mm, and the height of the trapezoidal teeth is 6 mm.

[0148] The arc-shaped rectifier plate I has 170 rectifier holes with a diameter of 1.5 mm; the arc-shaped rectifier plate II has 210 rectifier holes with a diameter of 1 mm.

[0149] The process parameters include: component back pressure 185 bar, spinneret extrusion temperature 295℃, cooling air temperature 20.5℃, air humidity 81.5%, air pressure 19 Pa, oil content 0.42%, winding speed 2750 m / min, winding machine is Barmag Wings 40T-1500 / 10 winding head, the concentration of the oiling agent is 9 wt% (made by mixing crude oil of model Dryfi HL165M with pure water), and network pressure 0.82 bar.

[0150] The final multi-shaped composite fiber has the following specifications: 30dtex / 22f, breaking elongation of 121.3%, breaking elongation CV value of 1.98%, breaking strength of 3.28cN / dtex, yarn unevenness CV value of 0.82%, full roll rate of 99.4%, and irregularity of 57%.

[0151] Example 6

[0152] A method for preparing multi-shaped composite fibers, using the preparation apparatus described in Example 1, is as follows:

[0153] Polyester melt (intrinsic viscosity 0.660 dl / g, end carboxyl group content 25 mol / t, diethylene glycol content 1.0 wt%) was extruded through a spinneret, and then subjected to cooling, bundling, oiling, and winding processes to prepare multi-shaped composite fibers; wherein:

[0154] Preparation apparatus used: The outer diameter of the spinneret is 60 mm;

[0155] The number of C-type spinnerets is 14, and the number of fan-type spinnerets is 10;

[0156] The spacing between two adjacent C-type spinnerets is 7.5 mm, the spacing between two adjacent triangular spinnerets is 7.5 mm, and the spacing between two adjacent fan-shaped spinnerets is 6 mm.

[0157] The central angle of the arc is 92°, and the diameter of the circle corresponding to the arc is 0.48 mm; the side length of the equilateral triangle is 0.14 mm.

[0158] The three arcs intersect at one point. The outlet shape of the fan-shaped spinneret remains unchanged when rotated 360° around this point. The central angle of each arc is 175°, and the diameter of the circle corresponding to each arc is 0.17mm.

[0159] The slope of the feed ramp is 1:3;

[0160] The inner diameter of the annular sealing groove is 1mm smaller than the outer diameter of the upper end of the inverted frustum cylinder;

[0161] The gap between the bases of two adjacent trapezoidal teeth is 2mm, and the height of the trapezoidal teeth is 6mm.

[0162] The arc-shaped rectifier plate I has 170 rectifier holes with a diameter of 1.5 mm; the arc-shaped rectifier plate II has 210 rectifier holes with a diameter of 1 mm.

[0163] The process parameters include: component back pressure 185 bar, spinneret extrusion temperature 295℃, cooling air temperature 20℃, air humidity 81%, air pressure 19 Pa, oil content 0.41%, winding speed 2800 m / min, winding machine is Barmag Wings 40T-1500 / 10 winding head, the concentration of the oiling agent is 9 wt% (made by mixing crude oil of model Dryfi HL165M with pure water), and network pressure 0.81 bar.

[0164] The final multi-shaped composite fiber has the following specifications: 33dtex / 24f, breaking elongation of 122.6%, breaking elongation CV value of 1.64%, breaking strength of 3.35cN / dtex, yarn unevenness CV value of 0.81%, full roll rate of 99.5%, and irregularity of 58%.

Claims

1. A device for preparing multi-shaped composite fibers, comprising a cooling duct (4), a component housing (1.3), and a top cover (1.6), a self-sealing gasket (1.2), a flow divider (1.1), a sand cup (1.4), and a spinneret (2) arranged from top to bottom within the component housing (1.3), wherein the top cover (1.6) is provided with a melt inlet hole, and the spinneret (2) is provided with spinneret holes, characterized in that, There are three types of spinnerets: C-type spinnerets (2.1), triangular spinnerets (2.2), and fan-shaped spinnerets (2.3). The outlet shape of the C-type spinneret (2.1) is an arc, the central angle of which is 90-93°, and the diameter of the circle corresponding to which the arc is 0.35-0.5mm; The outlet shape of the triangular spinneret (2.2) is an equilateral triangle with a side length of 0.1-0.15 mm; The outlet shape of the fan-shaped spinneret (2.3) is composed of 3 arcs, one end of which intersects at a point. The outlet shape of the fan-shaped spinneret (2.3) remains unchanged when rotated 120°, 240° or 360° around this point. The central angle of each arc is 150-180°, and the diameter of the circle corresponding to each arc is 0.12-0.18mm. The number of C-type spinnerets (2.1) and triangular spinnerets (2.2) is the same, and they correspond one-to-one. The triangular spinneret (2.2) is located inside the corresponding C-type spinneret (2.1), and the center of their outlet shapes coincides. One vertex of the outlet shape of the triangular spinneret (2.2) is directly opposite the opening of the outlet shape of the C-type spinneret (2.1). The spinneret (2) has two symmetrical and spaced-apart lens-shaped regions. The lens-shaped regions are surrounded by an inner arc and an outer arc. The inner arc and the outer arc are curved in opposite directions, and the outer arc coincides with the edge of the spinneret (2). All spinnerets are located within the lens-shaped area; within each lens-shaped area, C-type spinnerets (2.1) are arranged along the outer arc spacing and open towards the outer arc, while fan-shaped spinnerets (2.3) are arranged along the inner arc spacing.

2. The apparatus for preparing multi-shaped composite fibers according to claim 1, characterized in that, An electric heating tube (3.2) is provided inside the area between the two lens-shaped areas on the spinneret (2). The electric heating tube (3.2) is laid along the inner arc of the lens-shaped area. The minimum distance between the electric heating tube (3.2) and each fan-shaped spinneret hole (2.3) is the same. The minimum distance between the electric heating tube (3.2) and the C-shaped spinneret hole (2.1) is greater than the minimum distance between the electric heating tube (3.2) and each fan-shaped spinneret hole (2.3).

3. The apparatus for preparing multi-shaped composite fibers according to claim 2, characterized in that, The area between the two lens-shaped regions on the spinneret (2) is divided into upper and lower layers. The electric heating tube (3.2) is located in the lower layer, and each of the four corners of the lower layer has a through hole (3.3).

4. The apparatus for preparing multi-shaped composite fibers according to claim 1, characterized in that, The upper surface of the spinneret (2) is provided with an elliptical annular groove (2.4) and a circular annular groove (2.5). The centers of the elliptical annular groove (2.4) and the circular annular groove (2.5) coincide with the center of the spinneret (2). The elliptical annular groove (2.4) is surrounded by the circular annular groove (2.5). The fan-shaped spinneret (2.3) is located in the area enclosed by the elliptical annular groove (2.4), and the C-shaped spinneret (2.1) is located in the area enclosed by the elliptical annular groove (2.4) and the circular annular groove (2.5); The sand cup (1.4) is located above the spinneret (2). The interior of the sand cup (1.4) is provided with two arc-shaped vertical plates, which together form an inner cavity (1.42). The two arc-shaped vertical plates and the sand cup (1.4) together form two outer cavities (1.44). The bottom of both the inner cavity (1.42) and the outer cavity (1.44) are provided with through holes. The edge shape and size of the inner cavity (1.42) are the same as those of the elliptical annular groove (2.4) and are located directly above it. The edge shape and size of the sand cup (1.4) are the same as those of the circular annular groove (2.5) and are located directly above it. Two annular sealing gaskets are sandwiched between the sand cup (1.4) and the spinneret (2), which are located in the elliptical annular groove (2.4) and the circular annular groove (2.5), respectively.

5. The apparatus for preparing multi-shaped composite fibers according to claim 4, characterized in that, The inner chamber (1.42) is filled with 60-mesh metal sand and 50-mesh metal mesh, while the outer chamber (1.44) is filled with 40-mesh metal sand and 50-mesh metal mesh.

6. The apparatus for preparing multi-shaped composite fibers according to claim 4, characterized in that, The upper end of the inner chamber (1.42) is provided with two symmetrically distributed feed ramps (1.41). The two feed ramps (1.41) do not completely seal the upper end of the inner chamber (1.42). The feed ramps (1.41) are lower as they are closer to the center of the inner chamber (1.42). The slope of the feed ramps (1.41) is 1:2-3.

7. The apparatus for preparing multi-shaped composite fibers according to claim 6, characterized in that, The manifold (1.1) consists of a frustum (1.11) and multiple trapezoidal teeth (1.12); The frustum (1.11) is located above the two arc-shaped vertical plates and is coaxial with the sand cup (1.4). The upper end of the frustum (1.11) is located directly below the melt inlet hole. All the trapezoidal teeth (1.12) are clamped between the inner wall of the sand cup (1.4) and the bottom of the frustum (1.11). All the trapezoidal teeth (1.12) are fixedly connected to the bottom of the frustum (1.11) and are evenly distributed around the central axis of the frustum (1.11). The tooth root gap between two adjacent trapezoidal teeth (1.12) is 1-2 mm. Part of the tooth gap between all the trapezoidal teeth (1.12) is located above the outer cavity (1.44), and the other part is located above the inner cavity (1.42).

8. The apparatus for preparing multi-shaped composite fibers according to claim 7, characterized in that, The self-sealing gasket (1.2) consists of a frustum cylinder and an inverted frustum cylinder. Both the frustum cylinder and the inverted frustum cylinder are open at both ends. The inverted frustum cylinder is fitted on the frustum cylinder. The lower edge of the inverted frustum cylinder is connected to the lower edge of the frustum cylinder. The height of the inverted frustum cylinder is lower than that of the frustum cylinder. The inner wall of the sand cup (1.4) is provided with an annular sealing groove (1.31). The inner diameter of the annular sealing groove (1.31) is 0.5-1mm smaller than the outer diameter of the upper end of the inverted frustum cylinder. The upper edge of the inverted frustum cylinder is inserted into the annular sealing groove (1.31). The bottom of the top cover (1.6) is provided with a cylindrical protrusion. The melt inlet hole passes through the cylindrical protrusion and is coaxial with it. The upper edge of the frustum cylinder is fitted on the cylindrical protrusion. The self-sealing gasket (1.2) is supported by a flow divider plate (1.1).

9. The apparatus for preparing multi-shaped composite fibers according to claim 1, characterized in that, The cooling duct (4) consists of two arc-shaped rectifier plates I (4.2), two arc-shaped rectifier plates II (4.3), and two arc-shaped plates (4.4); The orthographic projections of the two arc-shaped rectifier plates I (4.2) completely coincide with the orthographic projections of the outer arcs of the two lens-shaped regions, and the orthographic projections of the two arc-shaped rectifier plates II (4.3) completely coincide with the orthographic projections of the inner arcs of the two lens-shaped regions. The two arc-shaped rectifier plates I (4.2) are connected by two arc-shaped plates (4.4) to form a complete cylinder. The number of rectifier holes in the arc-shaped rectifier plate I (4.2) is p, and the hole diameter is a; the number of rectifier holes in the arc-shaped rectifier plate II (4.3) is q, and the hole diameter is b; p<q,a> b.

10. A method for preparing multi-shaped composite fibers, characterized in that, The apparatus for preparing multi-shaped composite fibers as described in any one of claims 1-9 is used.

11. The method for preparing a multi-shaped composite fiber according to claim 10, characterized in that, The process flow is as follows: polyester melt extrusion → cooling and forming → bundling and oiling → winding and forming; The process parameters include: module back pressure 180-200 bar, spinneret extrusion temperature 295-296℃, cooling air temperature 19-22℃, air humidity 80-85%, air pressure 15-19 Pa, oil content 0.35-0.45%, and winding speed 2650-2800 m / min.

12. The method for preparing a multi-shaped composite fiber according to claim 11, characterized in that, The specifications of the multi-shaped composite fiber are 22-33dtex / 16-24f, the breaking elongation CV value is 1.64-2.16%, the yarn unevenness CV value is 0.78-0.85%, and the full roll rate is 99.1-99.5%.

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