A method for producing a herringbone fiber

Abstract

The present application belongs to the technical field of special-shaped fiber production, and relates to a production method of rice-shaped fiber, comprising a spinning assembly spinning process and a cooling process; ring blowing cooling and side blowing cooling are sequentially performed during cooling; the specification of the rice-shaped fiber is 83-150 dtex / 96-144 f. The present application optimizes the length of the ring blowing cylinder, the total length of the ring blowing cylinder and the side blowing net plate, and the side blowing speed, ensures uniform cooling, controls the pre-take-up degree of the fiber bundle, relieves internal stress concentration, avoids damage to the fiber bundle and decline of dyeing performance, and realizes stable production of high-quality rice-shaped fiber.

Description

A method for producing cross-shaped fibers Technical Field

[0001] This invention belongs to the field of irregular fiber production technology, and relates to a method for producing cross-shaped fibers. Background Technology

[0002] With continuous social progress and a significant improvement in people's living standards, consumers have placed higher demands on the comfort, functionality, and aesthetics of clothing. Against this backdrop, irregularly shaped fibers, due to their unique cross-sectional shape and excellent performance characteristics, have been widely used in various fields such as textiles and apparel, filter materials, filling materials, medical supplies, and industrial materials. Among them, herringbone fibers, with their high specific surface area, good bulkiness, and moisture-wicking properties, have become a popular choice in the market.

[0003] However, cooling is a crucial step in the production of herringbone fibers, directly affecting the fiber's shape and overall performance. Currently, the main methods for producing herringbone fibers are side-blowing cooling and ring-blowing cooling, but both methods have certain limitations.

[0004] Side-blowing cooling rapidly cools fibers using high-speed airflow, ensuring high fiber profile. For example, the literature (Process and characteristics of 67dtex / 72f fully dull wave flat polyester FDY [J]. Synthetic Fibers. 2023, 52(5): 18-20.) mentions that the faster the cooling rate, the higher the fiber profile. However, side-blowing cooling also has significant problems. Due to the high airflow velocity of the side-blowing air, the temperature difference between the inner and outer layers of the fiber bundle is large. This temperature difference effect easily causes stress concentration inside the fiber, leading to quality problems such as fuzz and breakage. At the same time, rapid cooling may also cause the fiber to form a core-sheath structure. This structural difference will further aggravate the fiber's breakage tendency during post-drawing and lead to poor dyeing performance. Specifically, when the length of the side-blowing mesh is set to a certain value (such as the common 1.5m), the side-blowing speed reaches a high level (such as above 1m / s). Although the fiber irregularity is improved, the proportion of fuzz and broken ends also increases significantly, and the dyeing uniformity decreases significantly.

[0005] In contrast, ring-blowing cooling effectively reduces temperature differences during the cooling process by uniformly blowing air from the outer circumference of the fiber bundle towards its center, resulting in a more uniform cooling effect. However, ring-blowing cooling also has its inherent drawbacks. Due to the relatively slow airflow velocity of the ring-blowing airflow, the cooling time is correspondingly prolonged, leading to a decrease in fiber profile. For example, in patent application CN107130311A (a semi-dull polyester fine denier POY fiber and its production method), when using ring-blowing cooling, the height of the windless zone in the ring-blowing duct is 45mm, the air temperature is 22℃, and the air pressure is 15-20Pa. While these cooling conditions ensure uniform cooling of the fiber, the profile is significantly reduced, failing to meet the market demand for fibers with high profile.

[0006] In summary, the production of star-shaped fibers faces significant challenges, particularly in the cooling process. How to ensure both the degree of irregularity and the overall performance of the fiber, thereby achieving stable production of high-quality star-shaped fibers, is a pressing technical problem that needs to be solved. Therefore, developing a novel cooling technology or optimizing existing cooling methods to balance irregularity and overall fiber performance has significant practical implications and application value. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art and provide a method for producing cross-shaped fibers.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for producing a cross-shaped fiber includes a spinning process using a spinning assembly and a cooling process, wherein the cooling process involves sequentially performing ring-blowing cooling and side-blowing cooling.

[0010] The annular blowing pressure is 14-20 Pa, the length of the annular blowing duct is 16-18 cm, the total length of the annular blowing duct and the side blowing mesh plate is 66-73 cm, and the side blowing velocity is 0.60-0.70 m / s;

[0011] The specifications of the cross-shaped fiber are 83-150 dtex / 96-144f.

[0012] Because of its eight-angled cross-section, the herringbone fiber requires rapid cooling to improve its irregular shape. However, this fiber is characterized by its large surface area, allowing it to dissipate heat more easily and cool faster than other fiber types under the same cooling conditions. But this also presents a problem: rapid cooling leads to a significant increase in the temperature difference between the inner and outer layers of the fiber bundle. This temperature difference causes tensile stress to concentrate in localized areas on the surface of the bundle, making it prone to damage such as fuzzing and breakage. Furthermore, rapid cooling degrades the fiber's dyeing properties, thus affecting subsequent processing and use.

[0013] However, choosing relatively mild cooling conditions can reduce the temperature difference between the inner and outer layers of the fiber bundle and decrease the risk of fiber damage, but this also prolongs the cooling time. This leads to a decrease in fiber shapeability, failing to meet the requirements for fiber shapeability.

[0014] Therefore, when cooling the cross-shaped fibers, a balance needs to be found: the cooling rate must be fast enough to improve the irregularity, while avoiding problems such as fiber bundle damage and decreased dyeing performance caused by rapid cooling.

[0015] To achieve cooling effect quickly and ensure fiber shape, this invention shortens the length of the annular blower to 16-18 cm to reduce the time it takes for the melt stream to return to a circular cross-section under surface tension. If the annular blower is too short, insufficient fiber cooling will affect the final strength and elongation properties of the product. If the annular blower is too long, the large surface area of ​​the shaped fibers will cause the fiber bundle to easily cool and solidify, leading to an upward shift of the solidification point during spinning. Furthermore, it will increase the interference of external wind within the blower, causing severe fiber swaying and affecting the evenness of the product.

[0016] On the other hand, this invention employs side-blowing cooling after annular air cooling. Side-blowing cooling provides relatively intense cooling conditions, allowing for rapid cooling of the fiber bundle. This invention designs the total length of the annular air blower and side-blowing screen to be 66-73 cm, ensuring uniform fiber cooling and good fiber evenness. If the total length of the annular air blower and side-blowing screen is too short, the cooling in this section will not completely remove the heat generated during fiber condensation. Even after passing through the natural slow cooling zone, the fiber bundle will not reach the appropriate temperature, resulting in incomplete fiber morphology stability and increased difficulty in bundling and oiling. If the total length of the annular air blower and side-blowing screen is too long, it will increase spinning tension, increasing friction as the fiber bundle enters the bundling ceramic component, leading to increased fuzz and breakage.

[0017] The side-blowing velocity of this invention is designed to be 0.60-0.70 m / s, which falls between the rapid freezing rate (>1 m / s) and the slow relaxation rate (<0.5 m / s). This allows for better control of the pre-orientation of the fiber bundle. Simultaneously, moderate molecular chain relaxation alleviates internal stress concentration caused by high-speed stretching, preventing cross-sectional distortion due to anisotropic contraction and thus maintaining the fiber's shape. If the side-blowing velocity is too low, the fiber will not cool sufficiently, resulting in a lower pre-orientation and consequently reduced breaking strength. If the side-blowing velocity is too high, the fiber bundle will sway excessively, affecting the swaying of the fiber bundle within the preceding air duct and consequently impacting fiber evenness.

[0018] As a preferred technical solution:

[0019] In the above-described method for producing a cross-shaped fiber, the holes on the side-blown screen are honeycomb holes. The side-blown screen is divided into upper and lower sections. The length of the upper section is 18-22% of the total length of the upper and lower sections. The honeycomb hole diameter of the upper section is 20-30% of the honeycomb hole diameter of the lower section. The honeycomb hole diameter of the lower section is 0.5-0.6 mm.

[0020] Because the side-blowing velocity is relatively high, when the fiber bundle transitions directly from the annular airflow to the larger side-blowing velocity, the fiber bundle will be forced to shift outwards and cannot be centered, affecting the cooling uniformity of each filament within the annular airflow duct. Therefore, this invention designs the side-blowing mesh plate so that, under a larger side-blowing velocity, the upper section, limited by the smaller honeycomb aperture, has a smaller airflow volume than the lower section. This way, the fiber bundle experiences a smaller side-blowing velocity immediately after leaving the annular airflow duct, preventing positional shift. As the fiber bundle moves away from the annular airflow duct, the larger airflow velocity in the lower section has a negligible impact on the fiber bundle position. This invention controls the length of the upper section to 18-22% of the total length of the upper and lower sections because the fibers in this section are not yet fully cooled and are highly susceptible to interference from the cooling airflow. This interference significantly affects many final product performance indicators, especially the evenness of the yarn.

[0021] In the above-described method for producing a star-shaped fiber, the spinneret in the spinning assembly has a star-shaped spinneret hole. The star shape consists of a circle and eight strips that are connected to the circle and distributed radially. The diameter of the circle is 0.23±0.01mm, the length of the strips is 0.815-0.865mm, the width of the strips is 0.067-0.073mm, and the included angle between two adjacent strips is 45°.

[0022] In the above-described method for producing cross-shaped fibers, the number of spinneret holes is 96-144.

[0023] In the above-described method for producing a cross-shaped fiber, all the spinnerets are arranged in concentric circles, each consisting of five circles. The spinnerets on adjacent circles are staggered, which improves the cooling effect.

[0024] In the above-described method for producing cross-shaped fibers, the outer diameter of the spinneret is 95-104 mm, and the diameter of the outermost circle is 75-85 mm.

[0025] The production method of the rice-shaped fiber described above has the following overall process flow: melt is extruded through a metering pump → spinning assembly → cooling → oiling nozzle → guide hook → first pre-network → first guide roller → second pre-network → second guide roller → winding and forming.

[0026] In the above-described method for producing cross-shaped fibers, the distance between the oil nozzle and the spinneret in the spinning assembly is 95-105 cm.

[0027] Because the cross-shaped fiber has a large specific surface area, the frictional resistance between the fiber bundle and air, guiding devices, etc., is high, and the tension during spinning is also increased, making it prone to fuzzing and breakage. Therefore, to reduce spinning tension, it is necessary to raise the position of the oiling point in the bundle and reduce the distance between the oiling nozzle and the spinneret in the spinning assembly (in the prior art, the distance between the oiling nozzle and the spinneret in the spinning assembly is generally 110-130cm). The setting of "the total length of the ring blower and the side blower screen is 66-73cm" in this invention is also to take into account that the distance between the oiling nozzle and the lower end of the side blower screen should not be too small, otherwise the temperature during oiling will decrease, and low temperature will lead to the fluidity and permeability of the oil, resulting in uneven oiling of this product.

[0028] The production method of the above-described cross-shaped fiber includes the following process parameters: spinning box temperature 285-287℃, windless zone length 45-50mm, cooling air temperature 20-22℃, cooling air relative humidity 75-85%, first guide roller speed 2800-2920m / min, second guide roller speed 2810-2930m / min, first pre-network pressure 0.08-0.09MPa, second pre-network pressure 0.08-0.09MPa, and winding speed 2800-2920m / min.

[0029] In the above-described method for producing a cross-shaped fiber, during winding, the length of the filament bundle laid on the paper tube is 82.33-82.67% of the length of the paper tube.

[0030] The diameter of the paper tube is 124-125mm;

[0031] Set the diameter range of the yarn cake and its corresponding winding angle and contact pressure in the winding machine:

[0032] The initial winding angle (the winding angle at the start of winding) is 5.0°, and the initial contact pressure (the contact pressure between the yarn cake and the friction roller) is 140N;

[0033] When the diameter of the yarn cake (=diameter of the paper tube + 2×thickness of the yarn cake) is less than 130mm, the winding angle is 5.2° and the contact pressure is 140N;

[0034] When the diameter of the yarn cake is greater than or equal to 130 mm and less than 135 mm, the winding angle is 5.1° and the contact pressure is 140 N;

[0035] When the diameter of the yarn cake is greater than or equal to 135mm and less than 145mm, the winding angle is 5.4° and the contact pressure is 140N;

[0036] When the diameter of the yarn cake is greater than or equal to 145 mm and less than 180 mm, the winding angle is 5.6° and the contact pressure is 142 N.

[0037] When the diameter of the yarn cake is greater than or equal to 180 mm and less than 260 mm, the winding angle is 5.5° and the contact pressure is 150 N;

[0038] When the diameter of the yarn cake is greater than or equal to 260 mm and less than 320 mm, the winding angle is 5.3° and the contact pressure is 155 N;

[0039] When the diameter of the yarn cake is greater than or equal to 320 mm and less than 440 mm, the winding angle is 5.1° and the contact pressure is 160 N;

[0040] The switching winding angle (i.e., the winding angle when the spindle is switched to the new paper tube when a silk cake is fully wound) is 5.0°;

[0041] During winding, the winding tension is 35-40 cN;

[0042] After winding and forming, when the net weight of a single spindle of yarn cake is 15.5kg, the measured diameter of the yarn cake is 430-432mm.

[0043] When applying oil to the nozzle, the concentration of the oil is 10 wt%, and the oil content of the filament bundle is 0.38 wt%.

[0044] The production method of the cross-shaped fiber described above has the following characteristics: relative radial anisotropy of the cross-shaped fiber ≥24.1%, breaking strength ≥2.37cN / dtex, breaking elongation 123.2-126.4%, yarn unevenness CV value ≤1.68%, appearance defects (mainly referring to surface unevenness, overlapping yarns, and strand tangles) downgrade rate ≤0.71%, loose loop yarn downgrade rate ≤0.09%, and dyeing M rate of subsequent products ≥96.3%.

[0045] The present invention also provides a method for manufacturing high-quality cross-shaped fibers, including a winding process, wherein during winding, the length of the fiber bundle laid on the paper tube is 82.68-83% of the length of the paper tube;

[0046] The diameter of the paper tube is 124-125mm;

[0047] Set the diameter range of the yarn cake and its corresponding winding angle and contact pressure in the winding machine:

[0048] The initial winding angle is 4.2°, and the initial contact pressure is 140N;

[0049] When the diameter of the yarn cake is less than 136mm, the winding angle is 4.3° and the contact pressure is 140N;

[0050] When the diameter of the yarn cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6° and the contact pressure is 140 N.

[0051] When the diameter of the yarn cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9° and the contact pressure is 140 N.

[0052] When the diameter of the yarn cake is greater than or equal to 150 mm and less than 170 mm, the winding angle is 5.3° and the contact pressure is 142 N.

[0053] When the diameter of the yarn cake is greater than or equal to 170 mm and less than 190 mm, the winding angle is 5.5° and the contact pressure is 150 N;

[0054] When the diameter of the yarn cake is greater than or equal to 190 mm and less than 210 mm, the winding angle is 5.3° and the contact pressure is 155 N;

[0055] When the diameter of the yarn cake is greater than or equal to 210 mm and less than 280 mm, the winding angle is 5.2° and the contact pressure is 160 N.

[0056] When the diameter of the yarn cake is greater than or equal to 280 mm and less than 330 mm, the winding angle is 5.0° and the contact pressure is 170 N;

[0057] When the diameter of the yarn cake is greater than or equal to 330 mm and less than 440 mm, the winding angle is 4.9° and the contact pressure is 175 N.

[0058] Switch the winding angle to 4.2°.

[0059] The cohesion between the individual filaments in a star-shaped pattern is poor, causing bulging and an excessively large diameter of the filament cake during winding. This invention reduces the diameter of the filament cake during winding for the following reasons:

[0060] In existing technologies, during winding, the length of the filament bundle laid on the paper tube is 82.33-82.67% of the length of the paper tube. Compared with existing technologies, this invention increases the length of the filament bundle laid on the paper tube. Increasing the length of the filament bundle laid on the paper tube can reduce the diameter of the filament cake while keeping the weight of the filament cake constant. There are many ways to adjust the length of the filament bundle laid on the paper tube, but most of them involve computer forming programs and fork modifications, which are costly. This invention adjusts the length of the filament bundle laid on the paper tube by adjusting the ABCD values, without modifying the computer forming program and fork. Specifically, it only adjusts the maximum position of the forming plate and the fork blades to increase the intersection point of the filament bundle on the two fork blades, thereby increasing the filament laying surface on the paper tube.

[0061] During the reciprocating motion of the filament bundle, when the bundle is moved to both ends by the fork blades, its longitudinal length increases. The tension of the filament bundle at both ends is greater than that in the middle of the forming plate of the fork, causing tension imbalance and affecting the forming of the filament package. To solve this problem, existing technologies design the two ends of the forming plate below the fork blades as asymmetrical arcs, thereby balancing the tension of the filament bundle at both ends and in the middle, and keeping the roll forming stable. Since the shift fork blades are mounted on a dual rotor, which is driven to rotate by a double-sided toothed belt, the rotation of the dual rotor will cause the two sets of shift fork blades to rotate in opposite directions simultaneously. Therefore, the shift fork blades are divided into two groups: one group rotates clockwise and the other group rotates counterclockwise (as shown in Figure 5). The first group of shift fork blades are RU and LU, and the second group of shift fork blades are RO and LO (RU, LU, RO, and LO are the shift fork blade models). The values ​​ABCD are the maximum distances between the shift fork blades and the forming plate. Because the forming plate has an asymmetrical arc design, the maximum distance between each shift fork blade and the forming plate is different, resulting in four distance values: A, B, C, and D. That is, the maximum distances between the shift fork blades RU, LU, RO, and LO and the forming plate are A, B, C, and D, respectively.

[0062] The large diameter of this type of POY was addressed by optimizing the ABCD values ​​of the fork blades and the forming plate of the winding machine. Taking the Barmag ACW winding machine as an example, the range of the ABCD values ​​of the fork blades and the forming plate (as shown in Figure 4) was adjusted from ±0.07 to ±0.05, with the corresponding parameter values ​​decreasing by 0.1-0.2 mm. The specific adjustment values ​​are as follows:

[0063] The original values ​​of ABCD were:

[0064] A 14.4±0.07mm

[0065] B 12.8±0.07mm

[0066] C 12.6±0.07mm

[0067] D 14.2±0.07mm

[0068] The adjusted ABCD values ​​are:

[0069] A 14.3±0.05mm

[0070] B 12.6±0.05mm

[0071] C 12.5±0.05mm

[0072] D 14.0±0.05mm

[0073] Reducing the corresponding ABCD values ​​by 0.1-0.2 mm means decreasing the maximum distance between the shift fork blades and the forming plate, thereby extending the distance between every two shift forks. This is equivalent to increasing the filament laying surface on the paper tube, allowing for a reduction in the filament cake diameter while maintaining the same filament cake weight. A smaller deviation means a closer maximum distance between each shift fork blade and the forming plate, resulting in more uniform and consistent filament cake formation, thus achieving optimal process conditions.

[0074] The winding angle refers to the angle between the radial winding motion of the filament bundle and the transverse guide (three-lobe fork) motion during the winding process, directly affecting the forming quality of the yarn cake. Generally, the winding angle is above 5.0°. This is because if the winding angle is too small, the filament bundles are almost stacked parallel to each other, and under the friction of the friction rollers, the filament bundles are prone to slipping towards both ends, causing edge collapse. Conversely, a smaller winding angle means the filament bundles are closer together in parallel stacking, allowing for a smaller diameter, but this also results in the filament bundles slipping towards both ends.

[0075] In existing technology, when using paper tubes of the same diameter for winding, the diameter range of the yarn cake and its corresponding winding angle and contact pressure are set in the winding machine:

[0076] The initial winding angle is 5.0°, and the initial contact pressure is 140N;

[0077] When the diameter of the yarn cake is less than 130mm, the winding angle is 5.2° and the contact pressure is 140N;

[0078] When the diameter of the yarn cake is greater than or equal to 130 mm and less than 135 mm, the winding angle is 5.1° and the contact pressure is 140 N;

[0079] When the diameter of the yarn cake is greater than or equal to 135mm and less than 145mm, the winding angle is 5.4° and the contact pressure is 140N;

[0080] When the diameter of the yarn cake is greater than or equal to 145 mm and less than 180 mm, the winding angle is 5.6° and the contact pressure is 142 N.

[0081] When the diameter of the yarn cake is greater than or equal to 180 mm and less than 260 mm, the winding angle is 5.5° and the contact pressure is 150 N;

[0082] When the diameter of the yarn cake is greater than or equal to 260 mm and less than 320 mm, the winding angle is 5.3° and the contact pressure is 155 N;

[0083] When the diameter of the yarn cake is greater than or equal to 320 mm and less than 440 mm, the winding angle is 5.1° and the contact pressure is 160 N;

[0084] Switch the winding angle to 5.0°.

[0085] Compared to existing technologies, this invention reduces the winding angle without causing the filament bundle to slip towards both ends. This is because the fiber cross-section is shaped like a star (X), resulting in relatively low direct contact friction between the filament bundle and the friction roller. However, the sharp angles of the X-shaped fibers create mechanical interlocking between layers, increasing static friction and resisting lateral slippage. Simultaneously, this invention increases the contact pressure compared to existing technologies. This is related to the increased centripetal pressure of the outer filaments on the inner filaments as the yarn cake gradually enlarges. Increasing the contact pressure further reduces the diameter of the yarn cake. Furthermore, this invention employs a nine-step forming process, setting nine diameter ranges for each yarn cake, along with corresponding winding angles and contact pressures. This allows for more precise forming settings, especially for the bottom filament forming process, which is more rationally designed. This reduces the problem of filament bundle slippage and edge collapse that easily occurs when the forming angle is small.

[0086] As a preferred technical solution:

[0087] In the above-described method for manufacturing high-quality cross-shaped fibers, the winding tension is 15-20 cN during the winding process.

[0088] In existing technologies, a certain tension needs to be applied to the filament bundle during the winding process to ensure it is wound into a solid package. Because the centripetal pressure exerted by the outer filaments on the inner filaments increases with the package diameter, the actual radial pressure borne by the inner filaments is higher than that of the outer filaments. Even with uniform winding tension (35-40 cN), the inner filaments experience longer compression time, resulting in greater residual stress and a higher risk of edge bulging and poor forming. While reducing the winding tension can decrease the radial pressure on the inner filaments and improve their forming, insufficient tension can lead to an excessively large filament package diameter and, due to the shorter compression time and lower residual stress in the outer filaments, edge collapse may occur due to insufficient tension.

[0089] Compared with the prior art, the present invention reduces the winding tension. Because the present invention adjusts the length of the filament bundle on the paper tube and the winding angle to reduce the diameter of the filament cake, although the winding tension is reduced, the diameter of the filament cake will not be too large. Since the cross-section of the fiber is star-shaped, its rhombuses can form mechanical interlocking between layers, increasing the static friction between the filament bundles and resisting lateral slippage. Therefore, although the winding tension is reduced, the outer layer of the filament cake will not collapse.

[0090] The method for manufacturing high-quality cross-shaped fibers described above, after winding, has a measured diameter of 426-428 mm when the net weight of a single spindle yarn cake is 15.5 kg.

[0091] The method for manufacturing high-quality cross-shaped fibers as described above also includes an oiling process, wherein the concentration of the oiling agent is 15-18 wt% and the oil content of the fiber bundle is 0.48 ± 0.03 wt%.

[0092] In the prior art, when applying oil to the nozzle, the concentration of the oil agent is 10 wt% and the oil content of the filament bundle is 0.38 wt%. Compared with the prior art, the present invention increases the concentration of the oil agent and the oil content of the filament bundle, which can increase the cohesion and antistatic properties of the filament bundle and reduce the fuzz of the filament bundle in the ceramic parts and the network.

[0093] The method for manufacturing high-quality star-shaped fibers as described above further includes a spinning process of a spinning assembly and a cooling process; during cooling, ring-blowing cooling and side-blowing cooling are performed sequentially.

[0094] The annular blowing pressure is 14-20 Pa, the length of the annular blowing duct is 16-18 cm, the total length of the annular blowing duct and the side blowing mesh plate is 66-73 cm, and the side blowing velocity is 0.60-0.70 m / s;

[0095] The specifications of the cross-shaped fiber are 83-150 dtex / 96-144f.

[0096] The method for manufacturing high-quality star-shaped fibers described above involves a side-blown screen with honeycomb holes. The side-blown screen is divided into upper and lower sections. The length of the upper section is 18-22% of the total length of the upper and lower sections. The honeycomb hole diameter of the upper section is 20-30% of the honeycomb hole diameter of the lower section. The honeycomb hole diameter of the lower section is 0.5-0.6 mm.

[0097] As described above, in a method for manufacturing high-quality star-shaped fibers, the spinneret holes on the spinneret in the spinning assembly are star-shaped. The star shape consists of a circle and eight strips that are connected to the circle and distributed radially. The diameter of the circle is 0.23±0.01mm, the length of the strips is 0.815-0.865mm, the width of the strips is 0.067-0.073mm, and the included angle between two adjacent strips is 45°.

[0098] The spinneret has 96-144 spinneret holes; all the spinneret holes are arranged in concentric circles, each consisting of 5 circles, with the spinneret holes on adjacent circles being staggered.

[0099] The outer diameter of the spinneret is 95-104mm, and the diameter of the outermost circle is 75-85mm.

[0100] The manufacturing method of high-quality herringbone fiber described above has the following overall process flow: melt is extruded through a metering pump → spinning is spun by a spinning assembly → cooling → oiling with an oil nozzle → guide hook → first pre-networking → first guide roller → second pre-networking → second guide roller → winding and forming.

[0101] In the above-described method for manufacturing high-quality herringbone fibers, the distance between the oil nozzle and the spinneret in the spinning assembly is 95-105 cm.

[0102] The process parameters include: spinning box temperature 285-287℃, windless zone length 45-50mm, cooling air temperature 20-22℃, cooling air relative humidity 75-85%, first guide roller speed 2800-2920m / min, second guide roller speed 2810-2930m / min, first pre-network pressure 0.08-0.09MPa, second pre-network pressure 0.08-0.09MPa, and winding speed 2800-2920m / min.

[0103] The above-described method for manufacturing high-quality herringbone fibers has the following characteristics: relative radial anisotropy of the herringbone fibers ≥24.2%, breaking strength ≥2.4 cN / dtex, breaking elongation 123.1-126.1%, yarn unevenness CV value ≤1.70%, appearance molding defect degradation rate ≤0.05%, loose loop yarn degradation rate ≤0.04%, and dyeing M rate of subsequent products ≥95.8%.

[0104] Beneficial effects:

[0105] (1) By optimizing the length of the ring blower, the total length of the ring blower and the side blower plate, and the side blower speed, this invention ensures uniform cooling, controls the pre-orientation of the filament bundle, alleviates internal stress concentration, avoids filament bundle damage and dyeing performance degradation, and achieves stable production of high-quality cross-shaped fibers.

[0106] (2) By adjusting the ABCD value (maximum distance between the fork blade and the forming plate), the present invention does not require modification of the computer forming program and the fork. It only adjusts the maximum position of the forming plate and the fork blade, increases the junction point of the filament bundle on the two fork blades, thereby increasing the filament bundle laying surface on the paper tube. Under the premise of ensuring that the weight of the filament cake remains unchanged, the diameter of the filament cake is reduced, and the smaller the deviation, the more uniform and consistent the filament cake forming.

[0107] (3) This invention addresses the problem of uneven tension between the two ends and the middle of the filament bundle during the reciprocating motion of the fork blade. Although it does not change the existing technology's approach of designing the two ends of the forming plate below the fork blade as asymmetrical arcs, by optimizing and adjusting the ABCD values, the distance between the two fork blades is extended, which is equivalent to increasing the filament bundle's laying surface on the paper tube, thus helping to improve the quality of the filament cake forming.

[0108] (4) Compared with the prior art, the present invention reduces the winding angle. Because the rhombuses of the cross-shaped fibers can form mechanical interlocking between layers, the static friction between the fiber bundles is increased, resisting lateral slippage, while increasing the contact pressure, further reducing the diameter of the fiber cake.

[0109] (5) The present invention adopts a nine-step forming process, sets the diameter range of nine filament cakes, and sets the corresponding winding angle and contact pressure, making the forming settings more precise. In particular, the bottom filament forming process is set more reasonably, reducing the problem of filament bundles slipping to both ends and collapsing edges when the forming angle is small. Attached Figure Description

[0110] Figures 1 and 2 are schematic diagrams of the device used for cooling. Figure 1 is the front view and Figure 2 is the side view; where 1-wind box, 2-ring blower, 5-side blower mesh plate, 7-wind duct frame;

[0111] Figure 3 is a schematic diagram of the spinneret holes on the spinneret used in embodiment A1; where d1 represents the length of the strip, d2 represents the width of the strip, and d3 represents the diameter of the circle forming the star shape;

[0112] Figure 4 is a schematic diagram of the ABCD values;

[0113] Figure 5 is a schematic diagram of the fork structure and rotation method in wire bundle forming. Detailed Implementation

[0114] 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.

[0115] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0116] Intrinsic viscosity: According to GB / T 14190-2017 "Test Method for Fiber Grade Polyester (PET) Chips", the density was determined using an Ubbelohde viscometer by dissolving the sample in a mixed solvent of phenol and tetrachloroethane (mass ratio of phenol to tetrachloroethane 3:2), yielding a density of 1.235 g / cm³. 3 The sample solution is tested, and the outflow time of the solution in the Ubbelohde viscometer is measured. The relative viscosity of the solution is calculated by the ratio of the outflow time t of the sample solution to the outflow time t0 of the pure solvent. Based on the relative viscosity, the F factor is found from the F factor table. The intrinsic viscosity is obtained by dividing the F factor by the concentration of the sample solution (concentration of sample solution = sample weight / sample solution volume, where sample weight = 0.125 g and sample solution volume = 25 mL).

[0117] Relative radial anisotropy: According to the "Test Method for Anisotropy of Chemical Fibers" (FZ / T 50002-2013), the cross-section of the fiber is magnified by a microscope, and the radii of the inscribed circle and circumscribed circle in the fiber cross-section are calculated. The relative radial anisotropy D is then calculated using the following formula. R :

[0118] D R = (1-r / R)×100%;

[0119] In the formula, r is the radius of the inscribed circle in the fiber cross section (mm), and R is the radius of the circumscribed circle in the fiber cross section (mm).

[0120] Tensile strength and elongation at break: The polyester fibers prepared in each example were tested using a fully automatic single yarn tensile testing machine (model YG023B-Ⅱ) in accordance with GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments". The specific process was as follows: First, the polyester fibers were placed in an environment with a temperature of 20℃ and a humidity of 65% for 4 hours to acclimate them. Then, they were clamped by upper and lower clamps (clamping length of 250mm), and a pretension of 0.05cN / dtex was applied by a robot arm to stabilize the polyester fibers. At the beginning of the test, the lower clamp was stretched at a speed of 1000mm / min until the fibers broke. At the same time, the real-time data of the force sensor was recorded during the stretching process, and the relationship curve between strength and elongation was plotted by the data collection system. Finally, the tensile strength and elongation at break of the fibers were obtained through data processing and analysis.

[0121] Evenness coefficient (CV): According to the "Test Method for Evenness of Chemical Fiber Filaments - Capacitive Method" (GB / T 14346-2015), the USTER5 evenness tester was used for testing. The specific process is as follows: First, the filament bundle is placed in an environment with a temperature of (20±2)℃ and a humidity of (65±5)% for 2 hours to adjust the humidity. Then, the filament bundle is passed through the two plates of a capacitor at a uniform speed, and the mass in each equal interval is converted into an electrical signal. The percentage of the standard deviation of all test electrical signals to the average value is the evenness coefficient. The test speed is 200m / min, and the filament bundle test time is 2.5min.

[0122] Defective appearance and forming rate: Defective appearance and forming rate = Number of defective and forming pieces × 100% / Total number of pieces. The defects in appearance and forming include surface unevenness, overlapping threads, and strand tangling. Among them, surface unevenness refers to the unevenness of the end face of the yarn cake, which is divided into the situation where the two end faces of the yarn cake are convex, convex, or have depressions near the bottom of the paper tube; overlapping threads refer to one or more bundles of threads almost overlapping each other, forming a part that is higher than the normal end face; strand tangling refers to the situation where the yarn at both ends of the yarn tube deviates from the normal winding trajectory, changes from an arc to a string, and has a length ≥ 3cm.

[0123] Loose loop yarn downgrade rate: Loose loop yarn downgrade rate = number of loose loop yarns downgraded × 100% / total number of yarns, where loose loop yarns are single yarns that are exposed on the end face of the roll in an arc or loop shape and are not broken.

[0124] The dyeing uniformity (M rate) of the downstream products is determined according to GB / T 6508-2015 "Test Method for Dyeing Uniformity of Polyester Filament". After the sample is textured in the downstream process, it is woven into a 10cm sock leg and then dyed. The dyeing uniformity grade of the sock leg is then visually evaluated by comparing it with the gray scale of the color change. The dye used is 1.3wt% Disperse Blue 2BLN, the liquor ratio is 1:50, and the dyeing temperature is 100℃. Then, according to FZ / T 54038-2014 "Irregular Polyester Low Elastic Yarn", sock legs with a dyeing uniformity grade of less than 4 are defined as defective sock legs. The dyeing M rate is calculated as follows: (Total number of sock legs - Number of defective sock legs) / Total number of sock legs × 100%.

[0125] The cooling devices used in the following embodiments are shown in Figures 1 and 2, including a bellows 1, an annular blower 2, a side-blowing mesh plate 5, and a blower frame 7. The length of the annular blower 2 is 16-18cm, and the total length of the annular blower 2 and the side-blowing mesh plate is 66-73cm. The holes on the side-blowing mesh plate are honeycomb holes. The side-blowing mesh plate is divided into upper and lower sections. The length of the upper section is 18-22% of the total length of the upper and lower sections. The honeycomb hole diameter of the upper section is 20-30% of the honeycomb hole diameter of the lower section. The honeycomb hole diameter of the lower section is 0.5-0.6mm. The annular blower 2 is installed on the blower frame 7, and the lower end face of the annular blower 2 is parallel to the horizontal plane. The annular blower 2 is used for annular air cooling, and the side-blowing mesh plate 5 is used for side air cooling.

[0126] Example A1

[0127] A method for producing cross-shaped fibers, the specific steps of which are as follows:

[0128] (1) Preparation of melt;

[0129] The overall process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity 0.62 dL / g);

[0130] The relevant process parameters are as follows: slurry level 69%, PTA mass in slurry accounts for 69.6% of the total mass of PTA and EG; first esterification temperature 266℃, first esterification pressure 100kPa, second esterification temperature 273℃, second esterification pressure 34kPa, prepolymerization upper chamber temperature 278℃, prepolymerization upper chamber pressure 14kPa, prepolymerization lower chamber temperature 280℃, prepolymerization lower chamber pressure 2kPa, final polymerization inlet temperature 280℃, final polymerization outlet temperature 286℃, and final polymerization pressure 200Pa.

[0131] (2) Production of cross-shaped fibers;

[0132] The overall process flow is as follows: the melt is extruded through the metering pump → spinning is spun by the spinning assembly → cooling → oiling the nozzle → guide hook → first pre-networking → first guide roller → second pre-networking → second guide roller → winding and forming;

[0133] The process parameters include: spinning box temperature of 285℃, length of windless zone of 45mm, cooling air temperature of 22℃, relative humidity of cooling air of 75%, speed of first guide roller of 2800m / min, speed of second guide roller of 2810m / min, first pre-network pressure of 0.08MPa, second pre-network pressure of 0.08MPa, and winding speed of 2800m / min;

[0134] As shown in Figure 3, in the spinning assembly, the spinneret's spinnerets have a star-shaped pattern. This star-shaped pattern consists of a circle and eight radially distributed strips connected to the circle. The circle has a diameter of 0.22 mm, the strips have a length of 0.815 mm, and a width of 0.067 mm. The angle between two adjacent strips is 45°. All the spinnerets are concentrically distributed, with each concentric circle consisting of five circles. The spinnerets on adjacent circles are staggered. The first circle appearing from the inside out is designated as the first circle, with a diameter of 31 mm, followed by the second circle (42 mm), the third circle (53 mm), the fourth circle (64 mm), and the fifth circle (75 mm). The first circle has six spinnerets. The outer diameter of the spinneret is 95 mm.

[0135] During cooling, annular air cooling and side air cooling are performed sequentially; the annular air pressure is 18 Pa, the length of the annular air duct is 18 cm, the total length of the annular air duct and the side air mesh plate is 73 cm, and the side air velocity is 0.70 m / s; the holes on the side air mesh plate are honeycomb holes, and the side air mesh plate is divided into upper and lower sections. The length of the upper section is 18% of the total length of the upper and lower sections, the honeycomb hole diameter of the upper section is 20% of the honeycomb hole diameter of the lower section, and the honeycomb hole diameter of the lower section is 0.6 mm;

[0136] When applying oil to the nozzle, the concentration of the oil agent is 10 wt%, the oil content of the filament bundle is 0.38 wt%, and the distance between the oil nozzle and the spinneret in the spinning assembly is 95 cm.

[0137] During winding, the length of the filament bundle laid on the paper tube is 82.33% of the paper tube's length; the paper tube's diameter is 124 mm; the diameter range of the filament cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 5.0°, and the initial contact pressure is 140 N; when the filament cake diameter is less than 130 mm, the winding angle is 5.2°, and the contact pressure is 140 N; when the filament cake diameter is greater than or equal to 130 mm and less than 135 mm, the winding angle is 5.1°, and the contact pressure is 140 N; when the filament cake diameter is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4°, and the contact pressure is... The force is 140N; when the diameter of the yarn cake is greater than or equal to 145mm and less than 180mm, the winding angle is 5.6° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 180mm and less than 260mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 260mm and less than 320mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 320mm and less than 440mm, the winding angle is 5.1° and the contact pressure is 160N; the switching winding angle is 5.0°; during winding and forming, the winding tension is 40cN.

[0138] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 430 mm. The final specifications of the herringbone fiber are 135 dtex / 96f, relative radial anisotropy is 27.6%, breaking strength is 2.45 cN / dtex, breaking elongation is 123.9%, yarn evenness CV value is 1.04%, appearance forming defect degradation rate is 0.57%, loose loop yarn degradation rate is 0.08%, and dyeing M rate of subsequent products is 97.8%.

[0139] Example A2

[0140] A method for producing cross-shaped fibers, the specific steps of which are as follows:

[0141] (1) Preparation of melt;

[0142] The overall process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity 0.625 dL / g);

[0143] The relevant process parameters are as follows: slurry level 69.6%, PTA mass in slurry accounts for 69% of the total mass of PTA and EG; first esterification temperature 268℃, first esterification pressure 104kPa, second esterification temperature 275℃, second esterification pressure 35kPa, prepolymerization upper chamber temperature 278.5℃, prepolymerization upper chamber pressure 14.9kPa, prepolymerization lower chamber temperature 282℃, prepolymerization lower chamber pressure 3kPa, final polymerization inlet temperature 281℃, final polymerization outlet temperature 286.4℃, and final polymerization pressure 210Pa.

[0144] (2) Production of cross-shaped fibers;

[0145] The overall process flow is as follows: the melt is extruded through the metering pump → spinning is spun by the spinning assembly → cooling → oiling the nozzle → guide hook → first pre-networking → first guide roller → second pre-networking → second guide roller → winding and forming;

[0146] The process parameters include: spinning box temperature of 285.8℃, windless zone length of 46mm, cooling air temperature of 21℃, cooling air relative humidity of 78%, first guide roller speed of 2840m / min, second guide roller speed of 2850m / min, first pre-network pressure of 0.08MPa, second pre-network pressure of 0.08MPa, and winding speed of 2840m / min.

[0147] In the spinning assembly, the spinneret has a star-shaped pattern of spinnerets, consisting of a circle and eight radially distributed strips connected to the circle. The circle has a diameter of 0.23 mm, the strips have a length of 0.840 mm and a width of 0.070 mm, and the angle between two adjacent strips is 45°. All the spinnerets are arranged in concentric circles, each consisting of five circles. The spinnerets on adjacent circles are staggered. The first circle appearing from the inside out is designated as the first circle, with a diameter of 35.4 mm, followed by the second circle with a diameter of 47.8 mm, the third circle with a diameter of 60.2 mm, the fourth circle with a diameter of 72.6 mm, and the fifth circle with a diameter of 85 mm. The first circle has 16 spinnerets. The outer diameter of the spinneret is 104 mm.

[0148] During cooling, annular air cooling and side air cooling are performed sequentially; the annular air pressure is 14 Pa, the length of the annular air duct is 17 cm, the total length of the annular air duct and the side air mesh plate is 66 cm, and the side air velocity is 0.65 m / s; the holes on the side air mesh plate are honeycomb holes, and the side air mesh plate is divided into upper and lower sections. The length of the upper section is 20% of the total length of the upper and lower sections, the honeycomb hole diameter of the upper section is 22% of the honeycomb hole diameter of the lower section, and the honeycomb hole diameter of the lower section is 0.55 mm;

[0149] When applying oil to the nozzle, the concentration of the oil agent is 10wt%, the oil content of the filament bundle is 0.38wt%, and the distance between the oil nozzle and the spinneret in the spinning assembly is 100cm.

[0150] During winding, the length of the filament bundle laid on the paper tube is 82.5% of the paper tube's length; the paper tube diameter is 125mm; the diameter range of the filament cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 5.0°, and the initial contact pressure is 140N; when the filament cake diameter is less than 130mm, the winding angle is 5.2°, and the contact pressure is 140N; when the filament cake diameter is greater than or equal to 130mm and less than 135mm, the winding angle is 5.1°, and the contact pressure is 140N; when the filament cake diameter is greater than or equal to 135mm and less than 145mm, the winding angle is 5.4°, and the contact pressure is... The force is 140N; when the diameter of the yarn cake is greater than or equal to 145mm and less than 180mm, the winding angle is 5.6° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 180mm and less than 260mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 260mm and less than 320mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 320mm and less than 440mm, the winding angle is 5.1° and the contact pressure is 160N; the switching winding angle is 5.0°; during winding and forming, the winding tension is 38cN.

[0151] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 431 mm. The final specifications of the herringbone fiber are 150 dtex / 144f, the relative radial anisotropy is 25.8%, the breaking strength is 2.51 cN / dtex, the breaking elongation is 124.6%, the yarn unevenness CV value is 1.21%, the appearance forming defect degradation rate is 0.58%, the loose loop yarn degradation rate is 0.07%, and the dyeing M rate of the subsequent products is 98%.

[0152] Example A3

[0153] A method for producing cross-shaped fibers, the specific steps of which are as follows:

[0154] (1) Preparation of melt;

[0155] The overall process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity 0.628 dL / g);

[0156] The relevant process parameters are as follows: slurry level 69.5%, PTA mass in slurry accounts for 70% of the total mass of PTA and EG; first esterification temperature 269℃, first esterification pressure 107kPa, second esterification temperature 276℃, second esterification pressure 36kPa, prepolymerization upper chamber temperature 279℃, prepolymerization upper chamber pressure 15.4kPa, prepolymerization lower chamber temperature 283℃, prepolymerization lower chamber pressure 2.6kPa, final polymerization inlet temperature 283℃, final polymerization outlet temperature 288℃, and final polymerization pressure 250Pa.

[0157] (2) Production of cross-shaped fibers;

[0158] The overall process flow is as follows: the melt is extruded through the metering pump → spinning is spun by the spinning assembly → cooling → oiling the nozzle → guide hook → first pre-networking → first guide roller → second pre-networking → second guide roller → winding and forming;

[0159] The process parameters include: spinning box temperature of 286.4℃, windless zone length of 48mm, cooling air temperature of 21℃, cooling air relative humidity of 82%, first guide roller speed of 2880m / min, second guide roller speed of 2890m / min, first pre-network pressure of 0.09MPa, second pre-network pressure of 0.09MPa, and winding speed of 2880m / min;

[0160] In the spinning assembly, the spinneret has a star-shaped pattern of spinnerets, consisting of a circle and eight radially distributed strips connected to the circle. The circle has a diameter of 0.23 mm, the strips have a length of 0.84 mm and a width of 0.072 mm, and the angle between two adjacent strips is 45°. All the spinnerets are arranged in concentric circles, each consisting of five circles. The spinnerets on adjacent circles are staggered. The first circle appearing from the inside out is designated as the first circle, with a diameter of 27 mm, followed by the second circle with a diameter of 41.5 mm, the third circle with a diameter of 56 mm, the fourth circle with a diameter of 70.5 mm, and the fifth circle with a diameter of 85 mm. The first circle has 12 spinnerets. The outer diameter of the spinneret is 104 mm.

[0161] During cooling, annular air cooling and side air cooling are performed sequentially; the annular air pressure is 18Pa, the length of the annular air duct is 18cm, the total length of the annular air duct and the side air mesh plate is 70cm, and the side air velocity is 0.60m / s; the holes on the side air mesh plate are honeycomb holes, and the side air mesh plate is divided into upper and lower sections. The length of the upper section is 21% of the total length of the upper and lower sections, the honeycomb hole diameter of the upper section is 25% of the honeycomb hole diameter of the lower section, and the honeycomb hole diameter of the lower section is 0.5mm;

[0162] When applying oil to the nozzle, the concentration of the oil agent is 10wt%, the oil content of the filament bundle is 0.38wt%, and the distance between the oil nozzle and the spinneret in the spinning assembly is 100cm.

[0163] During winding, the length of the filament bundle laid on the paper tube is 82.61% of the paper tube's length; the paper tube diameter is 124 mm; the diameter range of the filament cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 5.0°, and the initial contact pressure is 140 N; when the filament cake diameter is less than 130 mm, the winding angle is 5.2°, and the contact pressure is 140 N; when the filament cake diameter is greater than or equal to 130 mm and less than 135 mm, the winding angle is 5.1°, and the contact pressure is 140 N; when the filament cake diameter is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4°, and the contact pressure is... The force is 140N; when the diameter of the yarn cake is greater than or equal to 145mm and less than 180mm, the winding angle is 5.6° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 180mm and less than 260mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 260mm and less than 320mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 320mm and less than 440mm, the winding angle is 5.1° and the contact pressure is 160N; the switching winding angle is 5.0°; during winding and forming, the winding tension is 35cN.

[0164] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 432 mm. The final specifications of the herringbone fiber are 83 dtex / 144f, the relative radial anisotropy is 26.1%, the breaking strength is 2.53 cN / dtex, the breaking elongation is 126.4%, the yarn unevenness CV value is 1.26%, the appearance forming defect degradation rate is 0.71%, the loose loop yarn degradation rate is 0.08%, and the dyeing M rate of the subsequent products is 97.5%.

[0165] Example A4

[0166] A method for producing cross-shaped fibers, the specific steps of which are as follows:

[0167] (1) Preparation of melt;

[0168] The overall process flow is as follows: slurry preparation → first esterification → second esterification → pre-polymerization → final polymerization → polyester melt (intrinsic viscosity 0.63 dL / g);

[0169] The relevant process parameters are as follows: slurry level 70%, PTA mass in slurry accounts for 71% of the total mass of PTA and EG; first esterification temperature 270℃, first esterification pressure 110kPa, second esterification temperature 277℃, second esterification pressure 38kPa, prepolymerization upper chamber temperature 280℃, prepolymerization upper chamber pressure 16kPa, prepolymerization lower chamber temperature 284℃, prepolymerization lower chamber pressure 2.2kPa, final polymerization inlet temperature 285℃, final polymerization outlet temperature 287.2℃, and final polymerization pressure 240Pa.

[0170] (2) Production of cross-shaped fibers;

[0171] The overall process flow is as follows: the melt is extruded through the metering pump → spinning is spun by the spinning assembly → cooling → oiling the nozzle → guide hook → first pre-networking → first guide roller → second pre-networking → second guide roller → winding and forming;

[0172] The process parameters include: spinning box temperature of 287℃, length of windless zone of 50mm, cooling air temperature of 20℃, relative humidity of cooling air of 85%, speed of first guide roller of 2920m / min, speed of second guide roller of 2930m / min, first pre-network pressure of 0.09MPa, second pre-network pressure of 0.09MPa, and winding speed of 2920m / min;

[0173] In the spinning assembly, the spinneret has a star-shaped pattern of spinnerets, consisting of a circle and eight radially distributed strips connected to the circle. The circle has a diameter of 0.24 mm, the strips have a length of 0.865 mm and a width of 0.073 mm, and the angle between two adjacent strips is 45°. All the spinnerets are arranged in concentric circles, each consisting of five circles. The spinnerets on adjacent circles are staggered. The first circle appearing from the inside out is designated as the first circle, with a diameter of 32 mm, followed by the second circle with a diameter of 43 mm, the third circle with a diameter of 54 mm, the fourth circle with a diameter of 65 mm, and the fifth circle with a diameter of 76 mm. The first circle has 12 spinnerets. The outer diameter of the spinneret is 96 mm.

[0174] During cooling, annular air cooling and side air cooling are performed sequentially; the annular air pressure is 20Pa, the length of the annular air duct is 16cm, the total length of the annular air duct and the side air duct is 73cm, and the side air velocity is 0.65m / s; the holes on the side air duct are honeycomb holes, and the side air duct is divided into upper and lower sections. The length of the upper section is 22% of the total length of the upper and lower sections, the honeycomb hole diameter of the upper section is 30% of the honeycomb hole diameter of the lower section, and the honeycomb hole diameter of the lower section is 0.55mm;

[0175] When applying oil to the nozzle, the concentration of the oil agent is 10wt%, the oil content of the filament bundle is 0.38wt%, and the distance between the oil nozzle and the spinneret in the spinning assembly is 105cm.

[0176] During winding, the length of the filament bundle laid on the paper tube is 82.67% of the paper tube's length; the paper tube diameter is 125mm; the diameter range of the filament cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 5.0°, and the initial contact pressure is 140N; when the filament cake diameter is less than 130mm, the winding angle is 5.2°, and the contact pressure is 140N; when the filament cake diameter is greater than or equal to 130mm and less than 135mm, the winding angle is 5.1°, and the contact pressure is 140N; when the filament cake diameter is greater than or equal to 135mm and less than 145mm, the winding angle is 5.4°, and the contact pressure is... The force is 140N; when the diameter of the yarn cake is greater than or equal to 145mm and less than 180mm, the winding angle is 5.6° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 180mm and less than 260mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 260mm and less than 320mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 320mm and less than 440mm, the winding angle is 5.1° and the contact pressure is 160N; the switching winding angle is 5.0°; during winding and forming, the winding tension is 40cN.

[0177] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 430 mm. The final specifications of the herringbone fiber are 83 dtex / 128f, relative radial anisotropy is 27.5%, breaking strength is 2.45 cN / dtex, breaking elongation is 125.8%, yarn evenness CV value is 1.18%, appearance forming defect degradation rate is 0.45%, loose loop yarn degradation rate is 0.09%, and the dyeing M rate of the subsequent product is 97.9%.

[0178] Example A5

[0179] A method for producing a cross-shaped fiber differs from Example A1 only in that the honeycomb pore size of the upper and lower sections of the side-blown mesh is the same, while the honeycomb pore size of the upper section is the same as in Example A1.

[0180] The final obtained cross-shaped fiber has a relative radial anisotropy of 24.1%, a breaking strength of 2.24 cN / dtex, a breaking elongation of 127.4%, a yarn unevenness CV value of 1.96%, a poor appearance degradation rate of 0.59%, a loose loop yarn degradation rate of 0.09%, and a dyeing M rate of 96.8% for subsequent products.

[0181] Example A6

[0182] A method for producing a cross-shaped fiber differs from Example A1 only in that the honeycomb pore size of the upper and lower sections of the side-blown mesh is the same, and the honeycomb pore size of the lower section is the same as in Example A1.

[0183] The final obtained cross-shaped fiber has a relative radial anisotropy of 27.3%, a breaking strength of 2.54 cN / dtex, a breaking elongation of 123.2%, a yarn unevenness CV value of 1.67%, a poor appearance degradation rate of 0.58%, a loose loop yarn degradation rate of 0.08%, and a dyeing M rate of 96.9% for subsequent products.

[0184] Example A7

[0185] A method for producing a cross-shaped fiber differs from Example A4 only in that the distance between the oil nozzle and the spinneret in the spinning assembly is 110 cm.

[0186] The final obtained cross-shaped fiber has a relative radial anisotropy of 27.1%, a breaking strength of 2.37 cN / dtex, a breaking elongation of 126.4%, a yarn unevenness CV value of 1.68%, a poor appearance degradation rate of 0.46%, a loose loop yarn degradation rate of 0.09%, and a dyeing M rate of 96.3% for subsequent products.

[0187] Comparative Example 1

[0188] A method for producing a cross-shaped fiber differs from Example A2 only in that the ring blowing pressure is 10 Pa.

[0189] The final obtained cross-shaped fiber has a relative radial anisotropy of 19.6%, a breaking strength of 2.11 cN / dtex, and a yarn unevenness CV value of 1.97%.

[0190] Compared to Comparative Example 1 and Example A2, the relative radial anomaly and breaking strength of the herringbone fiber were significantly reduced, while the evenness (CV) value was significantly increased. This is because the ring-blowing pressure was too low, resulting in a slower tow solidification speed and thus lower anomaly. Simultaneously, the insufficient penetration of the cooling air due to the low ring-blowing pressure led to inadequate fiber cooling, thus reducing the breaking strength. Furthermore, the low ring-blowing pressure made the fiber susceptible to interference from external airflow and the influence of the next section of side blowing, causing significant drift and swaying of the filament solidification point, ultimately increasing the product's evenness.

[0191] Comparative Example 2

[0192] A method for producing a cross-shaped fiber differs from Example A4 only in that the ring blowing pressure is 25 Pa.

[0193] The final obtained cross-shaped fiber had a yarn unevenness (CV) of 1.67% and a dyeing (M) rate of 96.2% for subsequent products.

[0194] Compared with Comparative Example 2 and Example A4, the evenness CV value of the cross-shaped fiber increased significantly, and the dyeing performance decreased significantly. This is because the excessive ring blowing pressure caused the fiber bundle to be rapidly cooled, which easily resulted in a core-sheath structure, leading to uneven internal structure of the fiber. This affected the penetration and diffusion of dye molecules in the fiber in subsequent products, thus reducing the dyeing performance. At the same time, the excessive air pressure caused the fiber bundle to shake violently, which destroyed the stability and uniformity of the fiber bundle during the forming process, resulting in differences in the cooling rate and degree of different parts of the fiber bundle, and thus increasing the evenness of the product.

[0195] Comparative Example 3

[0196] A method for producing cross-shaped fibers differs from Example A4 only in that the length of the annular blower is 14 cm.

[0197] The final obtained cross-shaped fiber has a breaking strength of 2.23 cN / dtex and a yarn unevenness CV value of 1.63%.

[0198] Compared with Comparative Example 3 and Example A4, the breaking strength of the cross-shaped fiber was significantly lower and the evenness CV value was significantly higher. This is because the length of the ring blower was too small, resulting in insufficient cooling of the fiber. In particular, this stage is the state before the fiber solidifies, which directly affects the tensile strength. At the same time, the length of the ring blower was too small, and when the cooling was not in place, it directly entered the side blowing. The side blowing was relatively violent, which caused the unsolidified monofilament to shake severely, thus increasing the evenness.

[0199] Comparative Example 4

[0200] A method for producing cross-shaped fibers differs from Example A3 only in that the length of the annular blower is 20cm.

[0201] The final obtained cross-shaped fiber had a yarn unevenness (CV) of 1.53%.

[0202] Compared with Comparative Example 4 and Example A3, the CV value of the unevenness of the cross-shaped fiber is significantly larger. This is mainly because the excessive length of the ring blower increases the interference of the fiber bundle with the external wind inside the blower, causing the fiber bundle to shake severely, thereby affecting the evenness of the product.

[0203] Comparative Example 5

[0204] A method for producing cross-shaped fibers differs from Example A2 only in that the total length of the ring blower and the side blower is 60cm.

[0205] The final obtained cross-shaped fiber had a yarn unevenness CV value of 1.49% and a loose loop yarn degradation rate of 0.11%.

[0206] Compared with Comparative Example 5 and Example A2, the unevenness of the cross-shaped fiber and the rate of reduction in loose loops were significantly increased. This is because the total length of the ring blower and the side blower is too small, which means that the cooling of this section does not completely remove the heat from the fiber during condensation. After passing through the natural slow cooling zone, the fiber bundle cannot reach the appropriate temperature, resulting in the fiber morphology not being completely stable. Therefore, the unevenness of the fiber increases, and the difficulty of bundling and oiling is increased, resulting in poor bundling and a large number of reductions in loose loops.

[0207] Comparative Example 6

[0208] A method for producing cross-shaped fibers differs from Example A4 only in that the total length of the ring blower and the side blower is 78cm.

[0209] The final grade reduction rate of loose-coil yarn was 0.17%.

[0210] Compared with Comparative Example 6 and Example A4, the rate of downgrading of loose loop yarns in the cross-shaped fiber is significantly larger. This is because the total length of the ring blower and the side blower is too large, which leads to an increase in spinning tension and an increase in the friction of the yarn bundle entering the bundled ceramic piece, resulting in a larger rate of downgrading of loose loop yarns.

[0211] Comparative Example 7

[0212] A method for producing a cross-shaped fiber differs from Example A3 only in that the side-blowing velocity is 0.50 m / s.

[0213] The final obtained cross-shaped fiber has a relative radial anisotropy of 21.3%, a breaking strength of 2.24 cN / dtex, and a yarn unevenness CV value of 1.94%.

[0214] Compared with Comparative Example 7 and Example A3, the relative radial anisotropy and breaking strength of the cross-shaped fiber were significantly reduced, while the evenness CV value was significantly increased. This is because the side-blowing speed was too low, resulting in insufficient fiber cooling and a low pre-orientation degree, which in turn reduced the breaking strength. Furthermore, the low pre-orientation degree increased the cross-sectional distortion of the fiber bundle due to anisotropic shrinkage, thus reducing the anisotropy. At the same time, the side-blowing speed was too low, making it susceptible to environmental factors (such as ambient wind) during actual production, which caused severe fiber bundle swaying, thus increasing the evenness.

[0215] Comparative Example 8

[0216] A method for producing a cross-shaped fiber differs from Example A1 only in that the side-blowing velocity is 0.80 m / s.

[0217] The final obtained cross-shaped fiber had a yarn unevenness (CV) value of 2.09%.

[0218] Compared with Comparative Example 8 and Example A1, the CV value of the unevenness of the cross-shaped fiber increased significantly. This is because if the side blowing speed is too high, the fiber bundle will sway a lot, which will also affect the swaying of the fiber bundle in the upper section of the air duct, thus affecting the fiber unevenness.

[0219] Example B1

[0220] A method for manufacturing high-quality herringbone fiber differs from Example A1 in that: when oiling the nozzle, the concentration of the oiling agent is 15.8 wt%, and the oil content of the fiber bundle is 0.47 wt%; during winding, the length of the fiber bundle laid on the paper tube is 82.68% of the length of the paper tube; the diameter of the paper tube is 125 mm; the diameter range of the fiber cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140 N; when the diameter of the fiber cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9°, and the contact pressure is 140 N; the diameter of the fiber cake... When the diameter is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the yarn cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the yarn cake is greater than or equal to 330mm and less than 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°; during winding and forming, the winding tension is 20cN.

[0221] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 427 mm. The final obtained cross-shaped fiber has a relative radial anisotropy of 27.5%, a breaking strength of 2.48 cN / dtex, a breaking elongation of 124.1%, a yarn unevenness CV value of 1.08%, a poor appearance degradation rate of 0.03%, a loose loop yarn degradation rate of 0.02%, and a dyeing M rate of 98.5% for subsequent products.

[0222] Example B2

[0223] A method for manufacturing high-quality herringbone fiber differs from Example A2 in that: when oiling the nozzle, the concentration of the oiling agent is 15 wt%, and the oil content of the fiber bundle is 0.45 wt%; during winding, the length of the fiber bundle laid on the paper tube is 82.75% of the length of the paper tube; the diameter of the paper tube is 124 mm; the diameter range of the fiber cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140 N; when the diameter of the fiber cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9°, and the contact pressure is 140 N; the diameter of the fiber cake is... When the diameter of the yarn cake is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the yarn cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the yarn cake is greater than or equal to 330mm and less than 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°; during winding and forming, the winding tension is 18cN.

[0224] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 428 mm. The final obtained cross-shaped fiber has a relative radial anisotropy of 25.9%, a breaking strength of 2.54 cN / dtex, a breaking elongation of 124.9%, a yarn unevenness CV value of 1.16%, a poor appearance degradation rate of 0.05%, a loose loop yarn degradation rate of 0.01%, and a dyeing M rate of 98.8% for subsequent products.

[0225] Example B3

[0226] A method for manufacturing high-quality herringbone fiber differs from Example A3 in that: when oiling the nozzle, the concentration of the oiling agent is 17 wt%, and the oil content of the fiber bundle is 0.50 wt%; during winding, the length of the fiber bundle laid on the paper tube is 82.86% of the length of the paper tube; the diameter of the paper tube is 125 mm; the diameter range of the fiber cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140 N; when the diameter of the fiber cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9°, and the contact pressure is 140 N; the diameter of the fiber cake is... When the diameter of the yarn cake is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the yarn cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the yarn cake is greater than or equal to 330mm and less than 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°; during winding and forming, the winding tension is 15cN.

[0227] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 426 mm. The final obtained cross-shaped fiber has a relative radial anisotropy of 26.1%, a breaking strength of 2.54 cN / dtex, a breaking elongation of 126.1%, a yarn unevenness CV value of 1.20%, a poor appearance degradation rate of 0.03%, a loose loop yarn degradation rate of 0.01%, and a dyeing M rate of 98.7% for subsequent products.

[0228] Example B4

[0229] A method for manufacturing high-quality herringbone fibers differs from Example A4 in that: when oiling the nozzle, the concentration of the oiling agent is 18 wt%, and the oil content of the fiber bundle is 0.51 wt%; during winding, the length of the fiber bundle laid on the paper tube is 83% of the length of the paper tube; the diameter of the paper tube is 124 mm; the diameter range of the fiber cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140 N; when the diameter of the fiber cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9°, and the contact pressure is 140 N; the diameter of the fiber cake... When the diameter of the wire cake is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the wire cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the wire cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the wire cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the wire cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the wire cake is greater than or equal to 330mm and less than 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°; during winding and forming, the winding tension is 16cN.

[0230] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 426 mm. The final obtained cross-shaped fiber has a relative radial anisotropy of 27.8%, a breaking strength of 2.47 cN / dtex, a breaking elongation of 125.3%, a yarn unevenness CV value of 1.13%, a poor appearance degradation rate of 0.04%, a loose loop yarn degradation rate of 0.02%, and a dyeing M rate of 98.8% for subsequent products.

[0231] Example B5

[0232] A method for manufacturing high-quality herringbone fibers differs from Example A5 in that: when oiling the nozzle, the concentration of the oiling agent is 16.5 wt%, and the oil content of the fiber bundle is 0.49 wt%; during winding, the length of the fiber bundle laid on the paper tube is 82.92% of the length of the paper tube; the diameter of the paper tube is 124 mm; the diameter range of the fiber cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140 N; when the diameter of the fiber cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9°, and the contact pressure is 140 N; the diameter of the fiber cake... When the diameter is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the yarn cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the yarn cake is greater than or equal to 330mm and less than 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°; during winding and forming, the winding tension is 19cN.

[0233] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 426 mm. The final obtained cross-shaped fiber has a relative radial anisotropy of 24.5%, a breaking strength of 2.46 cN / dtex, a breaking elongation of 124.0%, a yarn unevenness CV value of 1.29%, a poor appearance degradation rate of 0.05%, a loose loop yarn degradation rate of 0.04%, and a dyeing M rate of 95.8% for subsequent products.

[0234] Example B6

[0235] A method for manufacturing high-quality herringbone fiber differs from Example A6 in that: when oiling the nozzle, the concentration of the oiling agent is 16 wt%, and the oil content of the fiber bundle is 0.48 wt%; during winding, the length of the fiber bundle laid on the paper tube is 83.0% of the length of the paper tube; the diameter of the paper tube is 124 mm; the diameter range of the fiber cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140 N; when the diameter of the fiber cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9°, and the contact pressure is 140 N; the diameter of the fiber cake is... When the diameter of the yarn cake is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the yarn cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the yarn cake is greater than or equal to 330mm and less than 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°; during winding and forming, the winding tension is 19cN.

[0236] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 426 mm. The final obtained cross-shaped fiber has a relative radial anisotropy of 27.6%, a breaking strength of 2.57 cN / dtex, a breaking elongation of 123.1%, a yarn unevenness CV value of 1.35%, a poor appearance degradation rate of 0.03%, a loose loop yarn degradation rate of 0.04%, and a dyeing M rate of 98.3% for subsequent products.

[0237] Example B7

[0238] A method for manufacturing high-quality herringbone fibers differs from Example A7 in that: when oiling the nozzle, the concentration of the oiling agent is 18 wt%, and the oil content of the fiber bundle is 0.51 wt%; during winding, the length of the fiber bundle laid on the paper tube is 82.79% of the length of the paper tube; the diameter of the paper tube is 125 mm; the diameter range of the fiber cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140 N; when the diameter of the fiber cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 136 mm and less than 140 mm, the winding angle is 4.6°, and the contact pressure is 140 N; when the diameter of the fiber cake is greater than or equal to 140 mm and less than 150 mm, the winding angle is 4.9°, and the contact pressure is 140 N; the diameter of the fiber cake is... When the diameter of the yarn cake is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the yarn cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the yarn cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the yarn cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the yarn cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the yarn cake is greater than or equal to 330mm and less than 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°; during winding and forming, the winding tension is 15cN.

[0239] After winding, when the net weight of a single spindle yarn cake is 15.5 kg, the measured diameter of the yarn cake is 427 mm. The final obtained cross-shaped fiber has a relative radial anisotropy of 24.2%, a breaking strength of 2.40 cN / dtex, a breaking elongation of 125.9%, a yarn unevenness CV value of 1.70%, a poor appearance degradation rate of 0.04%, a loose loop yarn degradation rate of 0.01%, and a dyeing M rate of 96.8% for subsequent products.

[0240] Example B8

[0241] A method for manufacturing high-quality herringbone fiber differs from Example B1 only in that the winding tension is 35 cN during winding.

[0242] After winding and forming, when the net weight of a single spindle of yarn cake is 15.5 kg, the measured diameter of the yarn cake is 425 mm.

[0243] Example B9

[0244] A method for manufacturing high-quality herringbone fibers differs from Example B1 only in that: when oiling the nozzle, the concentration of the oiling agent is 10 wt%, and the oil content of the fiber bundle is 0.38 wt%.

[0245] The final grade reduction rate of the loose loop yarn of the herringbone fiber was 0.09%.

[0246] Comparing Example B1 and Example B8, it can be seen that by adjusting the length of the filament bundle laid on the paper tube and the winding angle, even if the winding tension is reduced, the diameter of the filament cake will not be too large.

[0247] Comparing Example B9 and Example B1, it can be seen that, compared with the prior art, increasing the concentration of the oiling agent and the oil content of the filament bundle can increase the cohesion of the filament bundle.

[0248] Comparing Examples A1-A7 and Examples B1-B7, it can be seen that, compared with the prior art, by adjusting the length of the filament bundle laid on the paper tube and the winding angle, the diameter of the filament cake can be reduced during winding.

Claims

1. A method for producing a cross-shaped fiber, the overall process flow being: melt extrusion via metering pump → spinning via spinning assembly → cooling → oiling via oil nozzle → guide hook → first pre-networking → first guide roller → second pre-networking → second guide roller → winding and forming, characterized in that, During cooling, ring-blowing cooling and side-blowing cooling are performed sequentially. In the spinning assembly, the spinneret's spinneret holes are in a star-shaped pattern, consisting of a circle and eight radially distributed strips connected to the circle. The circle's diameter is 0.23±0.01mm, the strips' length is 0.815-0.865mm, the strips' width is 0.067-0.073mm, and the angle between adjacent strips is 45°. The side-blowing screen has honeycomb holes, divided into upper and lower sections. The upper section's length is 18-22% of the total length of the two sections, and the honeycomb hole diameter of the upper section is 20-30% of that of the lower section. The lower section's honeycomb hole diameter is 0.5-0.6mm. The ring-blowing air pressure is 14-20Pa, and the ring-blowing tube's length is 16-18cm. The total length of the annular blower and the side-blowing mesh plate is 66-73cm, and the side-blowing air velocity is 0.60-0.70m / s. During winding, the length of the filament bundle laid on the paper tube is 82.68-83% of the length of the paper tube, and the winding tension is 15-20cN. The diameter of the paper tube is 124-125mm. The diameter range of the filament cake and its corresponding winding angle and contact pressure are set in the winding machine: the initial winding angle is 4.2°, and the initial contact pressure is 140N; when the diameter of the filament cake is less than 136mm, the winding angle is 4.3°, and the contact pressure is 140N; when the diameter of the filament cake is greater than or equal to 136mm and less than 140mm, the winding angle is 4.6°, and the contact pressure is 140N; when the diameter of the filament cake is greater than or equal to 140mm and less than... When the diameter of the wire cake is 150mm, the winding angle is 4.9° and the contact pressure is 140N; when the diameter of the wire cake is greater than or equal to 150mm and less than 170mm, the winding angle is 5.3° and the contact pressure is 142N; when the diameter of the wire cake is greater than or equal to 170mm and less than 190mm, the winding angle is 5.5° and the contact pressure is 150N; when the diameter of the wire cake is greater than or equal to 190mm and less than 210mm, the winding angle is 5.3° and the contact pressure is 155N; when the diameter of the wire cake is greater than or equal to 210mm and less than 280mm, the winding angle is 5.2° and the contact pressure is 160N; when the diameter of the wire cake is greater than or equal to 280mm and less than 330mm, the winding angle is 5.0° and the contact pressure is 170N; when the diameter of the wire cake is greater than or equal to... When the diameter is between 330mm and 440mm, the winding angle is 4.9° and the contact pressure is 175N; the switching winding angle is 4.2°, which is the winding angle when the spindle is switched to the new paper tube when a yarn cake is fully wound; after winding, when the net weight of a single yarn cake is 15.5kg, the measured diameter of the yarn cake is 426-428mm; the specifications of the herringbone fiber are 83-150dtex / 96-144f, relative radial anisotropy ≥24.2%, breaking strength ≥2.4cN / dtex, breaking elongation 123.1-126.1%, yarn unevenness CV value ≤1.70%, appearance forming defect degradation rate ≤0.05%, loose loop yarn degradation rate ≤0.04%, and dyeing M rate of subsequent products ≥95%.8%; among which, the downgrading rate for poor appearance molding = number of downgraded pieces with poor appearance molding × 100% / total number of pieces, and the downgrading situation for poor appearance molding includes surface unevenness, overlapping threads, and strand tripping; the downgrading rate for loose thread = number of downgraded loose thread × 100% / total number of pieces, and loose thread refers to single filaments that are exposed on the end face of the coil in an arc or loop shape and are not broken.

2. The method for producing a cross-shaped fiber according to claim 1, characterized in that, The spinneret has 96-144 spinneret holes.

3. The method for producing a cross-shaped fiber according to claim 2, characterized in that, All the spinnerets are arranged in concentric circles, which consist of 5 circles, with the spinnerets on adjacent circles being staggered.

4. The method for producing a cross-shaped fiber according to claim 3, characterized in that, The outer diameter of the spinneret is 95-104mm, and the diameter of the outermost circle is 75-85mm.

5. The method for producing a cross-shaped fiber according to claim 1, characterized in that, The distance between the oil nozzle and the spinneret in the spinning assembly is 95-105cm.

6. The method for producing a cross-shaped fiber according to claim 1, characterized in that, The process parameters include: spinning box temperature 285-287℃, windless zone length 45-50mm, cooling air temperature 20-22℃, cooling air relative humidity 75-85%, first guide roller speed 2800-2920m / min, second guide roller speed 2810-2930m / min, first pre-network pressure 0.08-0.09MPa, second pre-network pressure 0.08-0.09MPa, and winding speed 2800-2920m / min.

Images