Production method of fibers shaped like Chinese character'mi '

Abstract

The invention belongs to the technical field of special-shaped fiber production, and relates to a production method of a *-shaped fiber, which comprises a spinning assembly spinning process and a cooling process, during cooling, circular air blowing cooling and side air blowing cooling are sequentially carried out; and the specification of the fibers shaped like the Chinese character'mi 'is 83-150dtex / 96-144f. By optimizing the length of the annular blowing cylinder, the total length of the annular blowing cylinder and the side blowing screen plate and the side blowing air speed, the special-shaped degree of the *-shaped fibers is guaranteed, meanwhile, it is guaranteed that cooling is uniform, the pre-orientation degree of tows is controlled, internal stress concentration is relieved, tow damage and dyeing performance reduction are avoided, and stable production of the high-quality *-shaped fibers is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of special-shaped fiber production and relates to a production method of a rice-shaped fiber. Background Art

[0002] With the continuous progress of society and the remarkable improvement of people's living standards, consumers have put forward higher requirements for the comfort, functionality, and aesthetics of clothing. Against this background, special-shaped fibers have been widely used in many fields such as textile and clothing, filter materials, filling materials, medical supplies, and industrial materials due to their unique cross-sectional shapes and excellent performance characteristics. Among them, rice-shaped fibers have become a popular choice in the market due to their high specific surface area, good fluffiness, and moisture absorption and sweat discharge performance.

[0003] However, in the production process of rice-shaped fibers, the cooling link is a crucial step, which is directly related to the shape irregularity and comprehensive performance of the fibers. At present, the production of rice-shaped fibers mainly adopts two methods: side blowing cooling and ring blowing cooling, but both of these methods have certain limitations.

[0004] The side blowing cooling method rapidly cools the fibers through high-speed airflows to ensure that the fibers have a high shape irregularity. For example, it is mentioned in the literature (Process and Characteristics of 67dtex / 72f Fully Delustered Wave-Flat Polyester FDY [J]. Synthetic Fibers. 2023, 52(5): 18 - 20.) that the faster the cooling speed, the higher the shape irregularity of the fibers. However, the side blowing cooling also has significant problems. Due to the relatively fast airflow speed of the side blowing, the temperature difference between the inner and outer layers of the filament bundle is relatively large. This temperature difference effect easily causes stress concentration inside the fibers, which in turn leads to quality problems such as hairiness and broken ends. At the same time, rapid cooling may also cause the fibers to form a skin-core structure, and this structural difference will further exacerbate the fracture tendency of the fibers during the post-drawing process and result in poor dyeing performance. Specifically, when the length of the side blowing screen plate is set to a certain specific value (such as a common 1.5 m) and the side blowing airspeed reaches a relatively high level (such as above 1 m / s), although the shape irregularity of the fibers is improved, the proportion of hairiness and broken ends also increases significantly, and the dyeing uniformity also decreases significantly.

[0005] In contrast, the ring blowing cooling method evenly blows air from the outer circumference of the tow to the center of the tow, effectively reducing the temperature difference during the cooling process of the filaments and making the cooling effect more uniform. However, the ring blowing cooling also has its inherent defects. Since the air flow velocity of the ring blowing is relatively slow, the cooling time is correspondingly extended, which results in a decrease in the profile of the fiber. For example, in the patent application with publication number CN107130311A (a polyester semi-dull fine denier POY fiber and its production method), when the ring blowing cooling method is adopted, the height of the airless area in the ring blowing cylinder is 45 mm, the air temperature is 22 °C, and the air pressure is 15 - 20 Pa. Although such cooling conditions ensure the uniform cooling of the fiber, the profile is significantly reduced, unable to meet the market demand for fibers with high profile.

[0006] In summary, during the production process of the cross-shaped fiber, especially in the cooling link, it faces great challenges. How to balance the profile while taking into account the comprehensive properties of the fiber and achieve the stable production of high-quality cross-shaped fibers is a technical problem that urgently needs to be solved at present. Therefore, developing a new cooling technology or optimizing the existing cooling method to balance the profile and the comprehensive properties of the fiber has important practical significance and application value. Summary of the Invention

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

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

[0009] A production method for cross-shaped fibers includes a spinning process by a spinning assembly and a cooling process. During cooling, ring blowing cooling and side blowing cooling are carried out in sequence.

[0010] The ring blowing air pressure is 14 - 20 Pa, the length of the ring blowing cylinder is 16 - 18 cm, the total length of the ring blowing cylinder and the side blowing screen plate is 66 - 73 cm, and the side blowing air velocity is 0.60 - 0.70 m / s.

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

[0012] Due to the cross-shaped fiber having 8 included angles in its cross-section, in order to improve its profile, a rapid cooling method needs to be adopted. However, the characteristic of this fiber is that it has a relatively large specific surface area. Therefore, under the same cooling conditions, compared with other types of fibers, it is easier to dissipate heat and has a faster cooling speed. But this also brings a problem: the rapid cooling will cause a significant increase in the temperature difference between the inner and outer layers of the tow. This temperature difference will cause the tensile stress on the surface layer of the tow to concentrate in local areas, thus easily causing damage to the tow, such as forming hairiness and breakage. In addition, the rapid cooling will also make the dyeing performance of the fiber worse, thereby affecting subsequent processing and use.

[0013] However, if a relatively mild cooling condition is selected for cooling, although the temperature difference between the inner and outer layers of the tow can be reduced and the risk of tow damage can be reduced, it is equivalent to extending the cooling time. This will lead to a decrease in the degree of profile and fail to meet the requirements for fiber profile.

[0014] Therefore, when cooling the M-shaped fibers, a balance needs to be found, which is to ensure that the cooling speed is fast enough to improve the degree of special shape, while avoiding problems such as damage to the yarn bundle and decreased dyeing performance caused by rapid cooling.

[0015] In order to achieve the cooling effect in a short time and ensure the fiber profile, on the one hand, the present invention shortens the length of the annular blower to 16-18 cm to reduce the time for the melt stream to recover to a circular cross-section under the action of surface tension. If the length of the annular blower is too short, the fiber will not be cooled enough, affecting the final strength and elongation of the product; if the length of the annular blower is too long, the filament bundle will be easily cooled and solidified due to the large specific surface area of ​​the shaped fiber, resulting in the upward movement of the solidification point on the spinning process, and the filament bundle will be disturbed by the external wind in the blower, causing the filament bundle to shake severely, thereby affecting the uniformity of the product.

[0016] On the other hand, the present invention performs side-blowing cooling after the ring-blowing cooling. The cooling conditions of the side-blowing cooling are relatively severe, and the filament bundle can be cooled quickly. The present invention designs the total length of the ring-blowing air cylinder and the side-blowing screen plate to be 66-73cm, which can ensure uniform cooling of the fiber and good uniformity of the fiber strands. If the total length of the ring-blowing air cylinder and the side-blowing screen plate is too small, the heat of fiber condensation will not be completely taken away by this cooling section, and the filament bundle cannot reach the appropriate temperature after passing through the natural slow cooling zone, resulting in the fiber morphology not being completely stable, increasing the difficulty of bundling and oiling. If the total length of the ring-blowing air cylinder and the side-blowing screen plate is too large, the spinning tension will increase, increasing the friction of the filament bundle entering the bundling porcelain component, resulting in an increase in hairy fibers and broken ends.

[0017] The side blowing wind speed of the present invention is designed to be 0.60-0.70m / s, which is between the rapid freezing rate (>1m / s) and the slow relaxation rate (<0.5m / s), which can better control the pre-orientation degree of the tow. At the same time, the appropriate molecular chain relaxation can alleviate the internal stress concentration caused by high-speed stretching, avoid the cross-sectional distortion of the tow due to anisotropic contraction, and thus maintain the profile. If the side blowing wind speed is too low, the fiber will not be cooled enough, the pre-orientation degree will be low, and the breaking strength will decrease. If the side blowing wind speed is too high, the tow will shake greatly, which will also affect the shaking of the tow in the upper section of the wind tube, and thus affect the unevenness of the fiber strands.

[0018] As the preferred technical solution:

[0019] A production method of the above-mentioned cross-shaped fiber, the holes on the side-blowing screen plate are honeycomb holes. The side-blowing screen 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 that of the lower section, and the honeycomb hole diameter of the lower section is 0.5-0.6 mm.

[0020] Due to the relatively large side-blowing wind speed, when the filament bundle directly transitions from the annular blowing to the relatively large side-blowing wind, the filament bundle will be forced to deflect outward and cannot be centered, affecting the cooling uniformity of each single filament in the annular blowing cylinder. Therefore, in the present invention, the side-blowing screen plate is designed. At a relatively large side-blowing wind speed, the air output of the upper section is less than that of the lower section due to the small honeycomb hole diameter. In this way, when the filament bundle just leaves the annular blowing cylinder, it is affected by a relatively small side-blowing wind and will not shift in position. As the filament bundle moves away from the annular blowing cylinder, the influence of the relatively large wind speed of the lower section on the position of the filament bundle can be almost ignored. In the present invention, the length of the upper section is controlled to be 18-22% of the total length of the upper and lower sections because the fibers in this section are not yet cooled sufficiently and are extremely vulnerable to the interference of the cooling wind, and this interference will significantly affect the final multiple performance indicators of the product, especially having a greater impact on the evenness of the strand.

[0021] A production method of the above-mentioned cross-shaped fiber, in the spinning pack, the spinneret holes on the spinneret plate are cross-shaped. The cross shape is composed of a circle and 8 long strips that are simultaneously connected to the circle and distributed radially. The diameter of the circle is 0.23±0.01 mm, the length of the long strip is 0.815-0.865 mm, the width of the long strip is 0.067-0.073 mm, and the included angle between adjacent two long strips is 45°.

[0022] A production method of the above-mentioned cross-shaped fiber, the number of spinneret holes on the spinneret plate is 96-144.

[0023] A production method of the above-mentioned cross-shaped fiber, all the spinneret holes are distributed in concentric circles. The concentric circles are composed of 5 circles, and the spinneret holes on adjacent two circles are staggeredly distributed, so as to improve the cooling effect.

[0024] A production method of the above-mentioned cross-shaped fiber, the outer diameter of the spinneret plate is 95-104 mm, and the diameter of the outermost circle is 75-85 mm.

[0025] A production method of the above-mentioned cross-shaped fiber, the overall process flow is: the melt is extruded by a metering pump → spinning by a spinning pack → cooling → oiling by an oil nozzle → a guide hook → the first pre-networking → the first godet roll → the second pre-networking → the second godet roll → winding and forming.

[0026] A production method of the above-mentioned cross-shaped fiber, the distance between the position of oiling by the oil nozzle and the spinneret plate in the spinning pack is 95-105 cm.

[0027] Since the specific surface area of the cross-shaped fibers is relatively large, the frictional resistance between the tow and air, wire guiding devices, etc. is large, and the tension in the spinning process also increases, making it easy to generate fuzz and breakage. Therefore, to reduce the spinning tension, it is necessary to increase the position of the bundling oiling point and reduce the distance between the oiling position of the oil nozzle and the spinneret plate in the spinning pack (in the prior art, the distance between the oiling position of the oil nozzle and the spinneret plate in the spinning pack is generally 110-130 cm). The present invention sets the "total length of the ring air blower and the side air blowing mesh plate to be 66-73 cm" also considering that the distance between the oiling position of the oil nozzle and the lower end of the side air blowing mesh plate should not be too small, otherwise the temperature during oiling will decrease, and the low temperature will cause the fluidity and permeability of the oil agent, resulting in uneven oiling of this variety.

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

[0029] A production method of cross-shaped fibers as described above, during winding and forming, the laying length of the tow on the paper tube is 82.33-82.67% of the length of the paper tube;

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

[0031] Set the diameter range of the cheese, and the corresponding winding angle and contact pressure in the winding machine:

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

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

[0034] When the diameter of the cheese 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 cheese is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4°, and the contact pressure is 140 N;

[0036] When the diameter of the cheese 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 cheese 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 cheese 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 cheese 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 switches to a new paper tube when a cheese is fully wound) is 5.0°;

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

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

[0043] When oiling with an oil nozzle, the concentration of the oil agent is 10 wt% and the oil content of the tow is 0.38 wt%.

[0044] For a production method of the cross-shaped fiber as described above, the relative radial shape irregularity of the cross-shaped fiber is ≥24.1%, the breaking strength is ≥2.37 cN / dtex, the breaking elongation is 123.2 - 126.4%, the CV value of the evenness variation is ≤1.68%, the downgrading rate due to poor appearance forming (mainly referring to surface unevenness, overlapping filaments, and snagging filaments) is ≤0.71%, the downgrading rate of loose loop filaments is ≤0.09%, and the M rate of dyeing of the subsequent product is ≥96.3%.

[0045] The present invention also provides a manufacturing method of a cross-shaped fiber with high forming quality, including a winding and forming process. During winding and forming, the laying length of the tow on the paper tube is 82.68 - 83% of the length of the paper tube;

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

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

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

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

[0050] When the diameter of the cheese 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 bobbin 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 bobbin 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 bobbin 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 bobbin 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 bobbin 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 bobbin 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 bobbin 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] The switching winding angle is 4.2°.

[0059] The cohesion between the cross-shaped monofilaments is poor, and the convex belly and the phenomenon of the too large diameter of the bobbin will be caused during the winding and forming process of the tow. The present invention can reduce the diameter of the bobbin during the winding and forming, and the reasons are as follows:

[0060] In the prior art, during winding, the laying length of the tow on the paper tube is 82.33 - 82.67% of the length of the paper tube; the present invention improves the laying length of the tow on the paper tube compared with the prior art. Increasing the laying length of the tow on the paper tube can reduce the diameter of the bobbin on the premise of ensuring the same weight of the bobbin; there are many optional ways to adjust the laying length of the tow on the paper tube, but most of them involve the computer forming program and the fork transformation, with high costs. The present invention adopts the method of adjusting the ABCD value to adjust the laying length of the tow on the paper tube, without the need to transform the computer forming program and the fork. Specifically, only the maximum position of the forming plate and the fork blade is adjusted, and the intersection point of the tow between the two fork blades is increased, so as to increase the laying surface of the tow on the paper tube.

[0061] During the reciprocating process of the tow, when the tow is deflected to both ends by the fork blades, the longitudinal length of the tow becomes longer, and the tension of the tow at both ends is greater than that of the tow at the middle position of the fork forming plate, resulting in uneven tension and affecting the formation of the cheese. To solve this problem, in the prior art, the two ends of the forming plate under the fork blades are designed as asymmetrical arcs, so as to balance the tension of the tow at both ends and in the middle, and keep the winding formation stable. Since the fork blades are installed on the double rotors, and the double rotors are driven to rotate by the double-sided toothed belt, when the double rotors rotate, they will drive the two groups of fork blades to rotate in opposite directions at the same time. Therefore, the fork blades are divided into two groups. One group of fork blades rotates clockwise, and the other group of fork blades rotates counterclockwise (as Figure 5 shown), the first group of fork blades is RU and LU, and the second group of fork blades is RO and LO (RU, LU, RO, LO are the fork blade models), and the ABCD value is the maximum distance between the fork blade and the forming plate. Because the forming plate is designed with an asymmetrical arc, the maximum distance between each fork blade and the forming plate is different. Therefore, there will be four distance values of ABCD, that is, the maximum distances between the fork blades RU, LU, RO and LO and the forming plate are the A value, the B value, the C value and the D value respectively.

[0062] By optimizing and adjusting the ABCD values of the fork blades and the forming plate of the winding machine, the problem of large POY diameter of this variety is solved. Taking the Barmag ACW winding machine as an example, the range of the ABCD values of the fork blades and the forming plate (as Figure 4 shown) is adjusted from the original ±0.07 to ±0.05, and the corresponding parameter values are successively reduced by 0.1 - 0.2 mm. The specific adjustment values are as follows:

[0063] The ABCD values before adjustment are:

[0064] A 14.4 ± 0.07 mm

[0065] B 12.8 ± 0.07 mm

[0066] C 12.6 ± 0.07 mm

[0067] D 14.2 ± 0.07 mm

[0068] The ABCD values after adjustment are:

[0069] A 14.3 ± 0.05 mm

[0070] B 12.6 ± 0.05 mm

[0071] C 12.5 ± 0.05 mm

[0072] D 14.0 ± 0.05 mm

[0073] When the corresponding ABCD value is adjusted down by 0.1 - 0.2 mm, it means reducing the maximum distance between the fork blade and the forming plate, thus extending the distance between the wire drawing of every two forks. That is equivalent to increasing the wire laying surface of the tow on the paper tube, so that the bobbin diameter can be reduced on the premise of keeping the bobbin weight unchanged. The smaller the deviation, the closer the maximum distance between each fork blade and the forming plate, making the forming of each bobbin more uniform and the bobbin forming more consistent, thus achieving the optimal process conditions.

[0074] The winding angle refers to the angle between the radial winding movement of the tow and the transverse wire guiding (three - leaf fork) movement during the winding process, which directly affects the forming quality of the bobbin. Generally, the winding angle is above 5.0°. This is because when the winding angle is too small, the tows are almost in parallel stacking. Under the friction force of the friction roller, it is easy for the tows to slip towards both ends, resulting in the problem of edge collapse. And the smaller the winding angle, the closer the distance between the direct parallel stacking of tows, so the diameter can be reduced, but there will be a problem of the tows slipping towards both ends.

[0075] In the prior art, when winding with paper tubes of the same diameter, the diameter range of the bobbin, its corresponding winding angle, and contact pressure are set in the winding machine:

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

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

[0078] When the bobbin 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;

[0079] When the bobbin 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 140 N;

[0080] When the bobbin diameter 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 bobbin diameter 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 bobbin diameter 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 bobbin diameter 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] The present invention reduces the winding angle compared with the prior art, but there will be no phenomenon of the fiber bundle slipping towards both ends. This is because the cross-section of the fiber is in a rice shape, and the direct contact friction force between the fiber bundle and the friction roller is relatively small. However, due to the edges of the rice-shaped fibers, mechanical interlocking can be formed between layers, increasing the static friction force between the fiber bundles and resisting lateral slippage. At the same time, the present invention increases the contact pressure compared with the prior art, which is related to the increase in the centripetal extrusion force of the outer layer of filaments on the inner layer of filaments as the cake gradually increases. Increasing the contact pressure can further reduce the diameter of the cake. In addition, the present invention adopts a nine-step forming process, that is, setting the diameter ranges of 9 cakes, and simultaneously setting the corresponding winding angles and contact pressures, making the forming settings more accurate. Especially, the forming process of the bottom layer of filaments is set more reasonably, reducing the problem that when the forming angle is small, the fiber bundle is prone to slip towards both ends and cause edge collapse.

[0086] As a preferred technical solution:

[0087] For the manufacturing method of the rice-shaped fiber with high forming quality as described above, during winding and forming, the winding tension is 15 - 20 cN.

[0088] In the prior art, during the winding process, a certain tension needs to be applied to the fiber bundle to wind the fiber bundle into a solid package. Since the centripetal extrusion force of the outer layer of filaments on the inner layer of filaments will increase as the diameter of the package increases, the actual radial pressure borne by the inner layer of filaments is higher than that of the outer layer. Although the winding tension is uniform (35 - 40 cN), due to the longer extrusion time of the inner layer of filaments, its residual stress is greater, which is prone to cause edge swelling and lead to poor forming. Although the winding tension can be reduced to reduce the radial pressure of the inner layer of filaments and improve the poor forming of the inner layer of filaments. However, due to too small a tension, on the one hand, it will cause the diameter of the cake to be too large, and on the other hand, it will cause the outer layer of filaments to have a short extrusion time and low residual stress, and may cause edge collapse due to insufficient tension.

[0089] The present invention reduces the winding tension compared with the prior art. Since the present invention adjusts the laying length of the fiber bundle on the paper tube and the winding angle to reduce the diameter of the cake, therefore, although the winding tension is reduced, it will not cause the diameter of the cake to be too large. Since the cross-section of the fiber is in a rice shape, its edges can form mechanical interlocking between layers, increasing the static friction force between the fiber bundles and resisting lateral slippage. Therefore, although the winding tension is reduced, the outer layer of the cake will not collapse.

[0090] For the manufacturing method of the rice-shaped fiber with high forming quality as described above, after winding and forming, when the net weight of a single spindle cake is 15.5 kg, the measured value of the diameter of the cake is 426 - 428 mm.

[0091] A manufacturing method of the above-mentioned star-shaped fiber with high forming quality further includes an oiling process at the oil nozzle. When oiling at the oil nozzle, the concentration of the oil agent is 15-18 wt%, and the oil content of the tow is 0.48±0.03 wt%.

[0092] In the prior art, when oiling at the oil nozzle, the concentration of the oil agent is 10 wt%, and the oil content of the tow 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 tow, which can increase the tow cohesion and antistatic property, and reduce the tow hairiness in porcelain parts and networks.

[0093] A manufacturing method of the above-mentioned star-shaped fiber with high forming quality further includes a spinning process of the spinning pack and a cooling process; during cooling, ring blowing cooling and side blowing cooling are carried out in sequence;

[0094] The ring blowing pressure is 14-20 Pa, the length of the ring blowing cylinder is 16-18 cm, the total length of the ring blowing cylinder and the side blowing screen plate is 66-73 cm, and the side blowing wind speed is 0.60-0.70 m / s;

[0095] The specification of the star-shaped fiber is 83-150 dtex / 96-144 f.

[0096] A manufacturing method of the above-mentioned star-shaped fiber with high forming quality, the holes on the side blowing screen plate are honeycomb holes, the side blowing screen 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, and the honeycomb hole diameter of the lower section is 0.5-0.6 mm.

[0097] A manufacturing method of the above-mentioned star-shaped fiber with high forming quality, in the spinning pack, the spinneret holes on the spinneret plate are star-shaped, the star shape is composed of a circle and 8 long strips that are simultaneously connected to the circle and distributed radially, the diameter of the circle is 0.23±0.01 mm, the length of the long strip is 0.815-0.865 mm, the width of the long strip is 0.067-0.073 mm, and the included angle between two adjacent long strips is 45°;

[0098] The number of spinneret holes on the spinneret plate is 96-144; all the spinneret holes are distributed in concentric circles, and the concentric circles are composed of 5 circles, and the spinneret holes on two adjacent circles are staggered;

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

[0100] A manufacturing method of the above-mentioned star-shaped fiber with high forming quality, the overall process flow is: the melt is extruded by a metering pump → spinning by the spinning pack → cooling → oiling at the oil nozzle → guide hook → first pre-network → first godet roller → second pre-network → second godet roller → winding and forming.

[0101] A manufacturing method of a cross-shaped fiber with high forming quality as described above, the distance between the oiling position on the nozzle and the spinneret plate in the spinning component is 95 - 105 cm;

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

[0103] A manufacturing method of a cross-shaped fiber with high forming quality as described above, the relative radial profile degree of the cross-shaped fiber ≥ 24.2%, the breaking strength ≥ 2.4 cN / dtex, the breaking elongation is 123.1 - 126.1%, the CV value of the evenness of yarn count ≤ 1.70%, the downgrading rate of poor appearance forming ≤ 0.05%, the downgrading rate of loose loop yarn ≤ 0.04%, and the M rate of dyeing of the subsequent product ≥ 95.8%.

[0104] Beneficial effects:

[0105] (1) By optimizing the length of the annular air-blowing cylinder, the total length of the annular air-blowing cylinder and the side-blowing screen plate, and the side-blowing air speed, the present invention ensures uniform cooling while ensuring the profile degree of the cross-shaped fiber, controls the pre-orientation degree of the filament bundle, alleviates the internal stress concentration, avoids filament bundle damage and the decline of dyeing performance, and realizes the stable production of high-quality cross-shaped fibers.

[0106] (2) By adjusting the ABCD value (the maximum distance between the fork blade and the forming plate), without modifying the computer forming program and the fork, only adjusting the maximum position of the forming plate and the fork blade, increasing the intersection point of the filament bundle between the two fork blades, thereby increasing the filament laying surface of the filament bundle on the paper tube. On the premise of ensuring the same cake weight, the cake diameter is reduced, and the smaller the deviation, the more uniform and consistent the cake forming is.

[0107] (3) Aiming at the problem of uneven tension between the two ends and the middle of the filament bundle during the reciprocating movement of the fork blade, although the present invention does not change the idea of designing the two ends of the forming plate under the fork blade as asymmetric arcs in the prior art, by optimizing and adjusting the ABCD value, the distance of wire guiding between every two fork blades is extended, which is equivalent to increasing the filament laying surface of the filament bundle on the paper tube, and helps to improve the cake forming quality.

[0108] (4) The present invention reduces the winding angle compared with the prior art. Since the rhombus corners of the cross-shaped fibers can form mechanical interlocking between layers, the static friction between the tow bundles is increased to resist lateral slippage. At the same time, the contact pressure is increased, further reducing the diameter of the bobbin.

[0109] (5) The present invention adopts a nine-step forming process, sets the diameter ranges of 9 bobbins, and simultaneously sets the corresponding winding angles and contact pressures, making the forming settings more accurate. In particular, the forming process settings for the bottom layer filaments are more reasonable, reducing the problems of tow slippage towards both ends and edge collapse that are prone to occur when the forming angle is small. Description of the Drawings

[0110] Figure 1 and Figure 2 is a schematic structural diagram of the device used during cooling, Figure 1 is the front view, Figure 2 is the side view; wherein, 1 - air box, 2 - ring blowing cylinder, 5 - side blowing mesh plate, 7 - cylinder rack;

[0111] Figure 3 is a schematic diagram of the spinneret holes on the spinneret plate used in Example A1; wherein, d1 represents the length of the strip, d2 represents the width of the strip, and d3 represents the diameter of the circle forming the cross 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 mode during tow forming. Detailed Embodiments

[0114] The following further elaborates the present invention in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

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

[0116] Intrinsic viscosity: According to GB / T 14190 - 2017 "Test Methods for Fiber - Grade Polyester (PET) Chips", it is measured using an Ubbelohde viscometer. The sample is dissolved in a mixed solvent of phenol and tetrachloroethane (the mass ratio of phenol to tetrachloroethane is 3:2) to obtain a density of 1.235 g / cm 3For the sample solution, measure the efflux time of the solution in an Ubbelohde viscometer. Calculate the relative viscosity of the solution from the ratio of the efflux time t of the sample solution to the efflux time t0 of the pure solvent. According to the relative viscosity, look up the F factor in the F factor table, and divide the F factor by the concentration of the sample solution (concentration of the sample solution = sample weight / sample solution volume, where the sample weight = 0.125 g and the sample solution volume = 25 mL) to obtain the intrinsic viscosity.

[0117] Relative radial irregularity: According to the "Test Method for the Irregularity of Chemical Fibers" (FZ / T 50002 - 2013), magnify the cross-section of the fiber through a microscope, calculate the radius of the inscribed circle and the radius of the circumscribed circle in the fiber cross-section, and calculate the relative radial irregularity D according to the following formula R :

[0118] D R =(1 - r / R)×100%;

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

[0120] Breaking strength, breaking elongation: Refer to the standard of GB / T 14344 - 2022 "Test Method for Tensile Properties of Chemical Fiber Filaments", use a full-automatic single yarn strength tester (model YG023B - Ⅱ) to measure the polyester fibers prepared in each example. The specific process is as follows: First, place the polyester fiber in an environment with a temperature of 20 °C and a humidity of 65% for humidity conditioning for 4 h. Then, clamp it with upper and lower clamps (the clamping length is 250 mm), and apply a pre-tension of 0.05 cN / dtex by a manipulator to stabilize the polyester fiber. When starting the test, the lower clamp pulls the filament bundle at a constant speed of 1000 mm / min until the filament bundle breaks. At the same time, record the real-time data of the force sensor during the stretching process, and draw the relationship curve between the strength and the elongation through a data collection system. Finally, through data processing and analysis, obtain the breaking strength and breaking elongation of the filament bundle.

[0121] Coefficient of variation (CV) of evenness: According to the "Test Method for Evenness of Chemical Fiber Filaments - Capacitance Method" (GB / T 14346 - 2015), use a USTER5 evenness tester for testing. The specific process is as follows: First, place the filament bundle in an environment with a temperature of (20 ± 2) °C and a humidity of (65 ± 5)% for humidity conditioning for 2 h. Then, pass the filament bundle through the two plates of the capacitor at a constant speed, convert the mass in each equal interval into an electrical signal, and the percentage of the standard deviation to the average value of all test electrical signals is the coefficient of variation of evenness; among them, the test speed is 200 m / min, and the filament bundle test time is 2.5 min.

[0122] Appearance forming defect downgrading rate: Appearance forming defect downgrading rate = (Number of products downgraded due to appearance forming defects) × 100% / Total number of products. The situations of appearance forming defects include surface unevenness, overlapping filaments, and snagged filaments. Among them, surface unevenness refers to the phenomenon of unevenness on the end face of the bobbin, which is divided into two cases: the two end faces of the bobbin are convex or convex-shouldered, or there is a depression near the bottom layer of the paper tube; overlapping filaments mean that one or more bundles of filaments almost overlap together, forming a part that is higher than the normal end face; snagged filaments refer to the situation where there are filaments at both ends of the bobbin that deviate from the normal winding trajectory, changing from an arc to a chord and with a length ≥ 3 cm.

[0123] Loose loop filament downgrading rate: Loose loop filament downgrading rate = (Number of products downgraded due to loose loop filaments) × 100% / Total number of products. Among them, loose loop filaments are single filaments that expose the winding end face in an arc or loop shape and are not broken.

[0124] Dyeing M rate of the subsequent product: According to the standard of GB / T 6508-2015 "Test Method for Dyeing Uniformity of Polyester Filament Yarns", after the sample to be tested is processed by post-spinning texturing, a 10-cm sock tube is woven and then dyed. Then, the dyeing uniformity grade of the sock tube is visually evaluated by comparing with the gray scale for color change. Among them, the dye used is 1.3 wt% Disperse Blue 2BLN, the bath ratio is 1:50, and the dyeing temperature is 100 °C. Then, according to the standard of FZ / T 54038-2014 "Special-shaped Polyester DTY", the sock tubes with a dyeing uniformity grade less than 4 are defined as defective sock tubes. Dyeing M rate = (Total number of sock tubes - Number of defective sock tubes) / Total number of sock tubes × 100%.

[0125] In the following examples, the device used for cooling is as Figure 1 、 Figure 2 shown, including an air box 1, an annular air blowing cylinder 2, a side blowing mesh plate 5, and an air cylinder frame 7. The length of the annular air blowing cylinder 2 is 16 - 18 cm, and the total length of the annular air blowing cylinder and the side blowing mesh plate is 66 - 73 cm. 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 that of the lower section, and the honeycomb hole diameter of the lower section is 0.5 - 0.6 mm. The annular air blowing cylinder 2 is installed on the air cylinder frame 7, and the lower end face of the annular air blowing cylinder 2 is parallel to the horizontal plane. The annular air blowing cylinder 2 is used for annular air blowing cooling, and the side blowing mesh plate 5 is used for side blowing cooling.

[0126] Example A1

[0127] A production method of a cross-shaped fiber is as follows:

[0128] (1) Preparation of the melt;

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

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

[0131] (2) Produce cross-shaped fibers;

[0132] The overall process flow is as follows: the melt is extruded by a metering pump → spun by a spinning pack → cooled → oiled at an oil nozzle → guided by a wire guide hook → first pre-network → first godet roll → second pre-network → second godet roll → winding and forming;

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

[0134] As Figure 3 shown, in the spinning pack, the spinneret holes on the spinneret plate are cross-shaped. The cross shape consists of a circle and 8 long strips that are connected to the circle and distributed radially. The diameter of the circle is 0.22 mm, the length of the long strip is 0.815 mm, the width of the long strip is 0.067 mm, and the included angle between two adjacent long strips is 45°; all the spinneret holes are distributed in concentric circles. The concentric circles consist of 5 circles. The spinneret holes on adjacent circles are staggered. The circle that first appears from the inside to the outside is denoted as the 1st circle. The diameter of the 1st circle is 31 mm, the diameter of the 2nd circle is 42 mm, the diameter of the 3rd circle is 53 mm, the diameter of the 4th circle is 64 mm, the diameter of the 5th circle is 75 mm, and 6 spinneret holes are distributed on the 1st circle; the outer diameter of the spinneret plate is 95 mm;

[0135] During cooling, annular blowing cooling and side blowing cooling are carried out in sequence; the annular blowing pressure is 18 Pa, the length of the annular blowing cylinder is 18 cm, the total length of the annular blowing cylinder and the side blowing mesh plate is 73 cm, and the side blowing wind speed is 0.70 m / s; 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% 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. The honeycomb hole diameter of the lower section is 0.6 mm;

[0136] When oiling the nozzle, the concentration of the oil agent is 10 wt%, the oil content of the tow is 0.38 wt%, and the distance between the oiling position on the nozzle and the spinneret in the spinning pack is 95 cm;

[0137] During winding and forming, the laying length of the tow on the paper tube is 82.33% of the length of the paper tube; the diameter of the paper tube is 124 mm; the diameter range of the cheese and its corresponding winding angle and contact pressure are set in the winding machine: the starting winding angle is 5.0°, and the starting contact pressure is 140 N; when the diameter of the cheese is less than 130 mm, the winding angle is 5.2°, and the contact pressure is 140 N; when the diameter of the cheese 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 diameter of the cheese is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4°, and the contact pressure is 140 N; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; the switching winding angle is 5.0°; during winding and forming, the winding tension is 40 cN.

[0138] After winding and forming, when the net weight of a single-end cheese is 15.5 kg, the measured value of the diameter of the cheese is 430 mm; the specifications of the finally produced cross-shaped fiber are 135 dtex / 96 f, the relative radial profile is 27.6%, the breaking strength is 2.45 cN / dtex, the breaking elongation is 123.9%, the CV value of the evenness variation is 1.04%, the downgrading rate due to poor appearance forming is 0.57%, the downgrading rate of loose loop yarn is 0.08%, and the M rate of the subsequent product dyeing is 97.8%.

[0139] Example A2

[0140] A production method of cross-shaped fiber, the specific steps are as follows:

[0141] (1) Preparation of the melt;

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

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

[0144] (2) Produce cross-shaped fibers;

[0145] The overall process flow is as follows: the melt is extruded by a metering pump → spun by a spinning pack → cooled → oiled at an oiling nozzle → passed through a godet hook → subjected to the first pre-network → passed through the first godet roller → subjected to the second pre-network → passed through the second godet roller → wound into shape;

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

[0147] In the spinning pack, the spinneret holes on the spinneret plate are cross-shaped. The cross shape consists of a circle and 8 long strips that are connected to the circle simultaneously and distributed radially. The diameter of the circle is 0.23 mm, the length of the long strip is 0.840 mm, the width of the long strip is 0.070 mm, and the angle between two adjacent long strips is 45°; all the spinneret holes are distributed in concentric circles. The concentric circles are composed of 5 circles. The spinneret holes on adjacent circles are staggeredly distributed. The circle that first appears from the inside to the outside is denoted as the 1st circle. The diameter of the 1st circle is 35.4 mm, the diameter of the 2nd circle is 47.8 mm, the diameter of the 3rd circle is 60.2 mm, the diameter of the 4th circle is 72.6 mm, the diameter of the 5th circle is 85 mm, and there are 16 spinneret holes distributed on the 1st circle; the outer diameter of the spinneret plate is 104 mm;

[0148] During cooling, annular blow air cooling and side blow air cooling are carried out in sequence; the annular blow air pressure is 14 Pa, the length of the annular blow air cylinder is 17 cm, the total length of the annular blow air cylinder and the side blow screen plate is 66 cm, and the side blow air speed is 0.65 m / s; the holes on the side blow screen plate are honeycomb holes. The side blow screen 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. The honeycomb hole diameter of the lower section is 0.55 mm;

[0149] When oiling the nozzle, the concentration of the oil agent is 10 wt%, the oil content of the tow is 0.38 wt%, and the distance between the oiling position on the nozzle and the spinneret in the spinning pack is 100 cm;

[0150] During winding and forming, the laying length of the tow on the paper tube is 82.5% of the length of the paper tube; the diameter of the paper tube is 125 mm; the diameter range of the cheese and its corresponding winding angle and contact pressure are set in the winding machine: the starting winding angle is 5.0°, and the starting contact pressure is 140 N; when the diameter of the cheese is less than 130 mm, the winding angle is 5.2°, and the contact pressure is 140 N; when the diameter of the cheese 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 diameter of the cheese is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4°, and the contact pressure is 140 N; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; the switching winding angle is 5.0°; during winding and forming, the winding tension is 38 cN.

[0151] After winding and forming, when the net weight of a single-end cheese is 15.5 kg, the measured value of the diameter of the cheese is 431 mm; the specification of the final produced cross-shaped fiber is 150 dtex / 144 f, the relative radial profile is 25.8%, the breaking strength is 2.51 cN / dtex, the breaking elongation is 124.6%, the CV value of the evenness variation is 1.21%, the downgrading rate due to poor appearance forming is 0.58%, the downgrading rate of loose coil yarn is 0.07%, and the M rate of dyeing for the subsequent product is 98%.

[0152] Example A3

[0153] A production method of cross-shaped fiber, the specific steps are as follows:

[0154] (1) Preparation of the melt;

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

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

[0157] (2) Produce rice-shaped fibers;

[0158] The overall process flow is as follows: the melt is extruded by a metering pump → spun by a spinning pack → cooled → oiled at an oil nozzle → guided by a godet hook → subjected to the first pre-network → passed through the first godet roller → subjected to the second pre-network → passed through the second godet roller → wound and formed;

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

[0160] In the spinning pack, the spinneret holes on the spinneret plate are in the shape of a rice character, which consists of a circle and 8 long strips that are simultaneously connected to the circle and radially distributed. The diameter of the circle is 0.23 mm, the length of the long strip is 0.84 mm, the width of the long strip is 0.072 mm, and the included angle between two adjacent long strips is 45°; all the spinneret holes are concentrically distributed, and the concentric circles are composed of 5 circles. The spinneret holes on adjacent circles are staggeredly distributed. The circle that first appears from the inside to the outside is recorded as the 1st circle. The diameter of the 1st circle is 27 mm, the diameter of the 2nd circle is 41.5 mm, the diameter of the 3rd circle is 56 mm, the diameter of the 4th circle is 70.5 mm, the diameter of the 5th circle is 85 mm, and there are 12 spinneret holes distributed on the 1st circle; the outer diameter of the spinneret plate is 104 mm;

[0161] During cooling, annular blow air cooling and side blow air cooling are carried out in sequence; the annular blow air pressure is 18 Pa, the length of the annular blow air cylinder is 18 cm, the total length of the annular blow air cylinder and the side blow screen plate is 70 cm, and the side blow air speed is 0.60 m / s; the holes on the side blow screen plate are honeycomb holes. The side blow screen 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 0.5 mm;

[0162] When oiling the nozzle, the concentration of the oil agent is 10 wt%, the oil content of the tow is 0.38 wt%, and the distance between the oiling position on the nozzle and the spinneret in the spinning pack is 100 cm;

[0163] During winding and forming, the laying length of the tow on the paper tube is 82.61% of the length of the paper tube; the diameter of the paper tube is 124 mm; in the winding machine, set the diameter range of the cheese, the corresponding winding angle and contact pressure: the starting winding angle is 5.0°, and the starting contact pressure is 140 N; when the diameter of the cheese is less than 130 mm, the winding angle is 5.2°, and the contact pressure is 140 N; when the diameter of the cheese 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 diameter of the cheese is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4°, and the contact pressure is 140 N; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; the switching winding angle is 5.0°; during winding and forming, the winding tension is 35 cN.

[0164] After winding and forming, when the net weight of a single-end cheese is 15.5 kg, the measured value of the diameter of the cheese is 432 mm; the specification of the final produced cross-shaped fiber is 83 dtex / 144 f, the relative radial profile is 26.1%, the breaking strength is 2.53 cN / dtex, the breaking elongation is 126.4%, the CV value of the evenness variation is 1.26%, the downgrading rate due to poor appearance forming is 0.71%, the downgrading rate of loose loop yarns is 0.08%, and the M rate of the subsequent product dyeing is 97.5%.

[0165] Example A4

[0166] A production method of cross-shaped fiber, the specific steps are as follows:

[0167] (1) Preparation of the melt;

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

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

[0170] (2) Produce cross-shaped fibers;

[0171] The overall process flow is as follows: the melt is extruded by a metering pump → spun by a spinning pack → cooled → oiled at an oil nozzle → guided by a wire guide hook → subjected to the first pre-network → passed through the first godet roll → subjected to the second pre-network → passed through the second godet roll → wound and formed;

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

[0173] In the spinning pack, the spinneret holes on the spinneret plate are cross-shaped. The cross shape consists of a circle and 8 long strips that are simultaneously connected to the circle and radially distributed. The diameter of the circle is 0.24 mm, the length of the long strip is 0.865 mm, the width of the long strip is 0.073 mm, and the included angle between adjacent two long strips is 45°; all the spinneret holes are concentrically distributed. The concentric circles consist of 5 circles. The spinneret holes on adjacent two circles are staggeredly distributed. The first circle that appears from the inside out is recorded as the 1st circle. The diameter of the 1st circle is 32 mm, the diameter of the 2nd circle is 43 mm, the diameter of the 3rd circle is 54 mm, the diameter of the 4th circle is 65 mm, the diameter of the 5th circle is 76 mm, and there are 12 spinneret holes distributed on the 1st circle; the outer diameter of the spinneret plate is 96 mm;

[0174] During cooling, ring blowing cooling and side blowing cooling are carried out in sequence; the ring blowing pressure is 20 Pa, the length of the ring blowing cylinder is 16 cm, the total length of the ring blowing cylinder and the side blowing screen plate is 73 cm, and the side blowing wind speed is 0.65 m / s; the holes on the side blowing screen plate are honeycomb holes. The side blowing screen plate 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. The honeycomb hole diameter of the lower section is 0.55 mm;

[0175] When oiling the nozzle, the concentration of the oil agent is 10 wt%, the oil content of the tow is 0.38 wt%, and the distance between the oiling position on the nozzle and the spinneret plate in the spinning pack is 105 cm;

[0176] During winding and forming, the laying length of the tow on the paper tube is 82.67% of the length of the paper tube; the diameter of the paper tube is 125 mm; the diameter range of the cheese, the corresponding winding angle and contact pressure are set in the winding machine: the starting winding angle is 5.0°, and the starting contact pressure is 140 N; when the diameter of the cheese is less than 130 mm, the winding angle is 5.2° and the contact pressure is 140 N; when the diameter of the cheese 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 diameter of the cheese is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4° and the contact pressure is 140 N; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; the switching winding angle is 5.0°; during winding and forming, the winding tension is 40 cN.

[0177] After winding and forming, when the net weight of a single spindle cheese is 15.5 kg, the measured value of the diameter of the cheese is 430 mm; the specification of the final produced cross-shaped fiber is 83 dtex / 128 f, the relative radial profile irregularity is 27.5%, the breaking strength is 2.45 cN / dtex, the breaking elongation is 125.8%, the CV value of the evenness variation is 1.18%, the downgrading rate due to poor appearance forming is 0.45%, the downgrading rate of loose loop yarns is 0.09%, and the M rate of the subsequent product dyeing is 97.9%.

[0178] Example A5

[0179] A production method of cross-shaped fiber, which is only different from Example A1 in that: the honeycomb pore diameters in the upper section and the lower section of the side-blowing screen plate are the same, and the honeycomb pore diameter in the upper section is the same as that in Example A1.

[0180] The relative radial profile irregularity of the finally produced cross-shaped fiber is 24.1%, the breaking strength is 2.24 cN / dtex, the breaking elongation is 127.4%, the CV value of the evenness variation is 1.96%, the downgrading rate due to poor appearance forming is 0.59%, the downgrading rate of loose loop yarns is 0.09%, and the M rate of the subsequent product dyeing is 96.8%.

[0181] Example A6

[0182] A production method of the cross-shaped fiber, the difference from Example A1 is only that: the honeycomb pore diameter in the upper section of the side-blowing screen plate is the same as that in the lower section, and the honeycomb pore diameter in the lower section is the same as that in Example A1.

[0183] The relative radial irregularity of the finally obtained cross-shaped fiber is 27.3%, the breaking strength is 2.54 cN / dtex, the breaking elongation is 123.2%, the CV value of the evenness variation is 1.67%, the downgrading rate due to poor appearance forming is 0.58%, the downgrading rate of loose-loop yarn is 0.08%, and the dyeing M rate of the subsequent product is 96.9%.

[0184] Example A7

[0185] A production method of the cross-shaped fiber, the difference from Example A4 is only that: the distance between the oiling position on the oil nozzle and the spinneret in the spinning component is 110 cm.

[0186] The relative radial irregularity of the finally obtained cross-shaped fiber is 27.1%, the breaking strength is 2.37 cN / dtex, the breaking elongation is 126.4%, the CV value of the evenness variation is 1.68%, the downgrading rate due to poor appearance forming is 0.46%, the downgrading rate of loose-loop yarn is 0.09%, and the dyeing M rate of the subsequent product is 96.3%.

[0187] Comparative Example 1

[0188] A production method of the cross-shaped fiber, the difference from Example A2 is only that: the ring blowing air pressure is 10 Pa.

[0189] The relative radial irregularity of the finally obtained cross-shaped fiber is 19.6%, the breaking strength is 2.11 cN / dtex, and the CV value of the evenness variation is 1.97%.

[0190] Compared with Example A2, in Comparative Example 1, the relative radial irregularity and breaking strength of the cross-shaped fiber are significantly reduced, and the CV value of the evenness variation is significantly increased. This is because the ring blowing air pressure is too small, resulting in a slower solidification and forming speed of the fiber bundle, leading to a lower irregularity. At the same time, the too low ring blowing air pressure causes insufficient penetration of the cooling air, resulting in insufficient cooling of the fiber, so the breaking strength is reduced; in addition, the too small ring blowing air pressure is easily affected by external air currents and the influence of the next-stage side blowing, causing obvious drift and shaking of the solidification point of the filament, and finally leading to an increase in the evenness variation of the product.

[0191] Comparative Example 2

[0192] A production method of the cross-shaped fiber, the difference from Example A4 is only that: the ring blowing air pressure is 25 Pa.

[0193] The CV value of the evenness variation of the finally obtained cross-shaped fiber is 1.67%, and the dyeing M rate of the subsequent product is 96.2%.

[0194] Compared with Comparative Example 2 and Example A4, the CV value of the unevenness rate of the M-shaped fiber increases significantly, and the dyeing performance decreases significantly. This is because the annular blowing air pressure is too high, which causes the filament bundle to be rapidly cooled, easily producing a skin-core structure, resulting in an uneven internal structure of the fiber, affecting the penetration and diffusion of dye molecules in the subsequent products in the fiber, thereby reducing the dyeing performance; at the same time, excessive wind pressure can cause the filament bundle to shake violently, destroying the stability and uniformity of the filament bundle during the molding process, resulting in differences in the cooling speed and degree of each part of the filament bundle, thereby increasing the unevenness rate of the product.

[0195] Comparative Example 3

[0196] A method for producing a rice-shaped fiber, which is different from Example A4 only in that the length of the ring-blowing cylinder is 14 cm.

[0197] The breaking strength of the finally obtained M-shaped fiber is 2.23 cN / dtex, and the CV value of the strand unevenness is 1.63%.

[0198] Compared with Example 3 and Example A4, the breaking strength of the M-shaped fiber is significantly lower, and the CV value of the yarn unevenness is significantly increased. This is because the length of the ring blowing cylinder is too short, resulting in insufficient cooling of the fiber, especially this stage is the state before the fiber solidifies, which directly affects the strength and elongation properties; at the same time, the length of the ring blowing cylinder is too short, and the side blowing is directly activated when the cooling is not in place, and the side blowing is relatively violent, resulting in severe shaking of the unsolidified monofilaments, so the yarn unevenness increases.

[0199] Comparative Example 4

[0200] A method for producing a rice-shaped fiber, which is different from Example A3 only in that the length of the ring-blowing air cylinder is 20 cm.

[0201] The CV value of the unevenness of the finally obtained M-shaped fiber is 1.53%.

[0202] Compared with Example A3, the CV value of the unevenness of the strands of the M-shaped fiber is significantly increased in Comparative Example 4. This is mainly because the excessive length of the annular blowing tube will increase the interference of the fiber bundles in the tube with the external wind, causing the fiber bundles to shake severely, thereby affecting the uniformity of the strands of the product.

[0203] Comparative Example 5

[0204] A method for producing a cross-shaped fiber, which is different from Example A2 only in that the total length of the ring-blowing air cylinder and the side-blowing screen plate is 60 cm.

[0205] The CV value of the unevenness of the finally obtained M-shaped fiber is 1.49%, and the downgrading rate of the loose loop fiber is 0.11%.

[0206] Compared with Comparative Example 5 and Example A2, the evenness CV value of the cross-shaped fibers and the downgrading rate of the loose loop yarns are significantly increased. This is because the total length of the ring air-blowing cylinder and the side air-blowing screen plate is too small, resulting in incomplete removal of the heat generated during fiber condensation in this section of cooling. After passing through the natural slow cooling zone, the appropriate temperature of the tow cannot be achieved, leading to incomplete stabilization of the fiber morphology. Therefore, the evenness CV value increases, and the difficulty of bundling and oiling is increased, resulting in poor bundling property and a large number of downgraded loose loop yarns.

[0207] Comparative Example 6

[0208] A production method of cross-shaped fibers, which only differs from Example A4 in that: the total length of the ring air-blowing cylinder and the side air-blowing screen plate is 78 cm.

[0209] The downgrading rate of the finally obtained loose loop yarns is 0.17%.

[0210] Compared with Comparative Example 6 and Example A4, the downgrading rate of the loose loop yarns of the cross-shaped fibers is significantly increased. This is because the total length of the ring air-blowing cylinder and the side air-blowing screen plate is too large, resulting in an increase in spinning tension and an increase in the friction force of the tow entering the bundling porcelain parts, leading to an increase in the downgrading rate of the loose loop yarns.

[0211] Comparative Example 7

[0212] A production method of cross-shaped fibers, which only differs from Example A3 in that: the side air-blowing speed is 0.50 m / s.

[0213] The relative radial shape irregularity of the finally obtained cross-shaped fibers is 21.3%, the breaking strength is 2.24 cN / dtex, and the evenness CV value is 1.94%.

[0214] Compared with Comparative Example 7 and Example A3, the relative radial shape irregularity and the breaking strength of the cross-shaped fibers are significantly reduced, and the evenness CV value is significantly increased. This is because the side air-blowing speed is too small, resulting in insufficient fiber cooling and a low pre-orientation degree. As a result, the breaking strength decreases, and the low pre-orientation degree increases the cross-section distortion of the tow due to anisotropic shrinkage, leading to a decrease in the shape irregularity; at the same time, the side air-blowing speed is too small, and it is prone to be affected by environmental factors (such as environmental wind) during the actual production process, resulting in serious shaking of the tow, so the evenness CV value increases.

[0215] Comparative Example 8

[0216] A production method of cross-shaped fibers, which only differs from Example A1 in that: the side air-blowing speed is 0.80 m / s.

[0217] The evenness CV value of the finally obtained cross-shaped fibers is 2.09%.

[0218] Compared with Comparative Example 8, the CV value of the evenness of the cross-shaped fibers in Example A1 increased significantly. This is because when the side blowing wind speed is too high, the filament bundle shakes greatly, which also affects the shaking of the filament bundle in the previous air duct, thereby affecting the evenness of the fiber.

[0219] Example B1

[0220] A method for manufacturing cross-shaped fibers with high forming quality, which is different from Example A1 in that: when applying oil on the oil nozzle, the concentration of the oil agent is 15.8 wt%, and the oil content of the filament bundle is 0.47 wt%; when winding and forming, the laying length of the filament bundle 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 silk cake and its corresponding winding angle and contact pressure are set in the winding machine: the starting winding angle is 4.2°, and the starting contact pressure is 140 N; when the diameter of the silk cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the silk 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 silk 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; when the diameter of the silk 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; when the diameter of the silk 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; when the diameter of the silk 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; when the diameter of the silk 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; when the diameter of the silk 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; when the diameter of the silk 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; the switching winding angle is 4.2°; when winding and forming, the winding tension is 20 cN.

[0221] After winding and forming, when the net weight of a single spindle silk cake is 15.5 kg, the measured value of the diameter of the silk cake is 427 mm; the relative radial irregularity of the finally obtained cross-shaped fibers is 27.5%, the breaking strength is 2.48 cN / dtex, the breaking elongation is 124.1%, the CV value of the evenness is 1.08%, the downgrading rate of poor appearance forming is 0.03%, the downgrading rate of loose loop silk is 0.02%, and the M rate of dyeing of the subsequent product is 98.5%.

[0222] Example B2

[0223] A manufacturing method of a cross-shaped fiber with high forming quality, different from Example A2 in that: when oiling through an oil nozzle, the concentration of the oil agent is 15 wt%, and the oil content of the tow is 0.45 wt%; during winding and forming, the laying length of the tow on the paper tube is 82.75% of the length of the paper tube; the diameter of the paper tube is 124 mm; set the diameter range of the cheese, and the corresponding winding angle and contact pressure in the winding machine: the starting winding angle is 4.2°, and the starting contact pressure is 140 N; when the diameter of the cheese is less than 136 mm, the winding angle is 4.3° and the contact pressure is 140 N; when the diameter of the cheese 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 cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; the switching winding angle is 4.2°; during winding and forming, the winding tension is 18 cN.

[0224] After winding and forming, when the net weight of a single-end cheese is 15.5 kg, the measured value of the diameter of the cheese is 428 mm; the relative radial irregularity of the finally produced cross-shaped fiber is 25.9%, the breaking strength is 2.54 cN / dtex, the breaking elongation is 124.9%, the CV value of the evenness variation is 1.16%, the downgrading rate due to poor appearance forming is 0.05%, the downgrading rate of loose-loop yarns is 0.01%, and the M rate of dyeing of the subsequent product is 98.8%.

[0225] Example B3

[0226] A manufacturing method of a cross-shaped fiber with high forming quality, different from Example A3 in that: when oiling through an oil nozzle, the concentration of the oil agent is 17 wt%, and the oil content of the tow is 0.50 wt%; during winding and forming, the laying length of the tow on the paper tube is 82.86% of the length of the paper tube; the diameter of the paper tube is 125 mm; set the diameter range of the cake, and the corresponding winding angle and contact pressure in the winding machine: the starting winding angle is 4.2°, and the starting contact pressure is 140 N; when the diameter of the cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the 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 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; the switching winding angle is 4.2°; during winding and forming, the winding tension is 15 cN.

[0227] After winding and forming, when the net weight of a single-cake is 15.5 kg, the measured value of the diameter of the cake is 426 mm; the relative radial irregularity of the finally obtained cross-shaped fiber is 26.1%, the breaking strength is 2.54 cN / dtex, the breaking elongation is 126.1%, the CV value of the evenness variation is 1.20%, the downgrading rate due to poor appearance forming is 0.03%, the downgrading rate of loose-loop yarns is 0.01%, and the M rate of dyeing of the subsequent product is 98.7%.

[0228] Example B4

[0229] A manufacturing method of a cross-shaped fiber with high forming quality, which is different from Example A4 in that: when oiling through the nozzle, the concentration of the oil agent is 18 wt%, and the oil content of the tow is 0.51 wt%; during winding and forming, the laying length of the tow 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 cheese and its corresponding winding angle and contact pressure are set in the winding machine: the starting winding angle is 4.2°, and the starting contact pressure is 140 N; when the diameter of the cheese is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the cheese 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 cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; when the diameter of the cheese 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; the switching winding angle is 4.2°; during winding and forming, the winding tension is 16 cN.

[0230] After winding and forming, when the net weight of a single-end cheese is 15.5 kg, the measured value of the diameter of the cheese is 426 mm; the relative radial irregularity of the finally produced cross-shaped fiber is 27.8%, the breaking strength is 2.47 cN / dtex, the breaking elongation is 125.3%, the CV value of the evenness variation is 1.13%, the downgrading rate due to poor appearance forming is 0.04%, the downgrading rate of loose loop yarns is 0.02%, and the M rate of dyeing of the subsequent product is 98.8%.

[0231] Example B5

[0232] A manufacturing method of a cross-shaped fiber with high forming quality, different from Example A5 in that: when applying oil on the nozzle, the concentration of the oil agent is 16.5 wt%, and the oil content rate of the tow is 0.49 wt%; during winding and forming, the laying length of the tow on the paper tube is 82.92% of the length of the paper tube; the diameter of the paper tube is 124 mm; set the diameter range of the cake, the corresponding winding angle and contact pressure in the winding machine: the starting winding angle is 4.2°, and the starting contact pressure is 140 N; when the diameter of the cake is less than 136 mm, the winding angle is 4.3° and the contact pressure is 140 N; when the diameter of the 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 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; switch the winding angle to 4.2°; during winding and forming, the winding tension is 19 cN.

[0233] After winding and forming, when the net weight of a single-cake is 15.5 kg, the measured value of the diameter of the cake is 426 mm; the relative radial irregularity of the finally produced cross-shaped fiber is 24.5%, the breaking strength is 2.46 cN / dtex, the breaking elongation is 124.0%, the CV value of the evenness variation is 1.29%, the downgrading rate due to poor appearance forming is 0.05%, the downgrading rate of loose loop yarns is 0.04%, and the M rate of the subsequent product dyeing is 95.8%.

[0234] Example B6

[0235] A manufacturing method of a cross-shaped fiber with high forming quality, different from Example A6 in that: when oiling through the nozzle, the concentration of the oil agent is 16 wt%, and the oil content of the tow is 0.48 wt%; during winding and forming, the laying length of the tow on the paper tube is 83.0% of the length of the paper tube; the diameter of the paper tube is 124 mm; set the diameter range of the cake, the corresponding winding angle and contact pressure in the winding machine: the starting winding angle is 4.2°, and the starting contact pressure is 140 N; when the diameter of the cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the 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 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; the switching winding angle is 4.2°; during winding and forming, the winding tension is 19 cN.

[0236] After winding and forming, when the net weight of a single-cake is 15.5 kg, the measured value of the diameter of the cake is 426 mm; the relative radial irregularity of the finally produced cross-shaped fiber is 27.6%, the breaking strength is 2.57 cN / dtex, the breaking elongation is 123.1%, the CV value of the evenness variation is 1.35%, the downgrading rate due to poor appearance forming is 0.03%, the downgrading rate of loose coiled yarn is 0.04%, and the M rate of dyeing of the subsequent product is 98.3%.

[0237] Example B7

[0238] A manufacturing method of a high-formed-quality cross-shaped fiber, which is different from Example A7 in that: when oiling through an oil nozzle, the concentration of the oil agent is 18 wt%, and the oil content of the tow is 0.51 wt%; when winding and forming, the laying length of the tow on the paper tube is 82.79% of the length of the paper tube; the diameter of the paper tube is 125 mm; set the diameter range of the cake, the corresponding winding angle and the contact pressure in the winding machine: the starting winding angle is 4.2°, and the starting contact pressure is 140 N; when the diameter of the cake is less than 136 mm, the winding angle is 4.3°, and the contact pressure is 140 N; when the diameter of the 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 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; when the diameter of the 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; the switching winding angle is 4.2°; when winding and forming, the winding tension is 15 cN.

[0239] After winding and forming, when the net weight of a single-cake is 15.5 kg, the measured value of the diameter of the cake is 427 mm; the relative radial irregularity of the finally prepared cross-shaped fiber is 24.2%, the breaking strength is 2.40 cN / dtex, the breaking elongation is 125.9%, the CV value of the evenness variation is 1.70%, the downgrading rate due to poor appearance forming is 0.04%, the downgrading rate of loose-loop yarns is 0.01%, and the M rate of the subsequent product dyeing is 96.8%.

[0240] Example B8

[0241] A manufacturing method of a high-formed-quality cross-shaped fiber, which is different from Example B1 only in that: when winding and forming, the winding tension is 35 cN.

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

[0243] Example B9

[0244] A manufacturing method of a cross-shaped fiber with high forming quality, which is only different from Example B1 in that when oiling through an oil nozzle, the concentration of the oil agent is 10 wt%, and the oil content of the tow is 0.38 wt%.

[0245] The downgrading rate of the loose coil wire of the finally obtained cross-shaped fiber is 0.09%.

[0246] Comparing Example B1 and Example B8, it can be seen that when the laying length of the tow on the paper tube and the winding angle are adjusted, even if the winding tension is reduced, it will not cause the diameter of the cheese to be too large.

[0247] Comparing Example B9 and Example B1, it can be seen that compared with the prior art, when the concentration of the oil agent and the oil content of the tow are increased, the tow cohesion can be increased.

[0248] Comparing Examples A1-A7 and Examples B1-B7, it can be seen that compared with the prior art, when the laying length of the tow on the paper tube and the winding angle are adjusted, the diameter of the cheese can be reduced during winding forming.

Claims

1. A production method of a cross-shaped fiber, comprising a spinning process of a spinning assembly and a cooling process, characterized in that, During cooling, ring blowing cooling and side blowing cooling are carried out in sequence; The ring blowing pressure is 14 - 20 Pa, the length of the ring blowing cylinder is 16 - 18 cm, the total length of the ring blowing cylinder and the side blowing screen plate is 66 - 73 cm, and the side blowing wind speed is 0.60 - 0.70 m / s; The specification of the cross-shaped fiber is 83 - 150 dtex / 96 - 144 f.

2. The production method of a cross-shaped fiber according to claim 1, characterized in that, The holes on the side blowing screen plate are honeycomb holes. The side blowing screen 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 that of the lower section. The honeycomb hole diameter of the lower section is 0.5 - 0.6 mm.

3. The production method of a cross-shaped fiber according to claim 1, characterized in that, In the spinning pack, the spinneret holes on the spinneret plate are in a cross shape. The cross shape consists of a circle and 8 long strips that are simultaneously connected to the circle and distributed radially. The diameter of the circle is 0.23 ± 0.01 mm, the length of the long strip is 0.815 - 0.865 mm, the width of the long strip is 0.067 - 0.073 mm, and the included angle between two adjacent long strips is 45°.

4. The production method of a cross-shaped fiber according to claim 3, characterized in that, The number of spinneret holes on the spinneret plate is 96 - 144.

5. The production method of a cross-shaped fiber according to claim 4, characterized in that All the spinneret holes are distributed in concentric circles. The concentric circles consist of 5 circles, and the spinneret holes on adjacent circles are staggeredly distributed.

6. The production method of a cross-shaped fiber according to claim 5, characterized in that, The outer diameter of the spinneret plate is 95 - 104 mm, and the diameter of the outermost circle is 75 - 85 mm.

7. A production method of a cross-shaped fiber according to any one of claims 1 to 6, characterized in that The overall process flow is: the melt is extruded by a metering pump → spun by a spinning pack → cooled → oiled by an oil nozzle → through a guide hook → the first pre-network → the first godet roller → the second pre-network → the second godet roller → winding and forming.

8. The production method of a cross-shaped fiber according to claim 7, characterized in that, The distance between the position of oiling by the oil nozzle and the spinneret plate in the spinning pack is 95 - 105 cm.

9. The production method of a cross-shaped fiber according to claim 7, characterized in that The process parameters include: the temperature of the spinning box is 285 - 287 °C, the length of the windless area is 45 - 50 mm, the cooling air temperature is 20 - 22 °C, the relative humidity of the cooling air is 75 - 85%, the speed of the first godet roller is 2800 - 2920 m / min, the speed of the second godet roller is 2810 - 2930 m / min, the pressure of the first pre-network is 0.08 - 0.09 MPa, the pressure of the second pre-network is 0.08 - 0.09 MPa, and the winding speed is 2800 - 2920 m / min.

10. A production method of a cross-shaped fiber according to claim 7, characterized in that, During winding and forming, the laying length of the tow on the paper tube is 82.33 - 82.67% of the length of the paper tube; The diameter of the paper tube is 124 - 125 mm; In the winding machine, set the diameter range of the cheese, and its corresponding winding angle and contact pressure: The starting winding angle is 5.0°, and the starting contact pressure is 140 N; When the diameter of the cheese is less than 130 mm, the winding angle is 5.2°, and the contact pressure is 140 N; When the diameter of the cheese 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 diameter of the cheese is greater than or equal to 135 mm and less than 145 mm, the winding angle is 5.4°, and the contact pressure is 140 N; When the diameter of the cheese 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; When the diameter of the cheese 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; When the diameter of the cheese 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; When the diameter of the cheese 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; Switch the winding angle to 5.0°; During winding forming, the winding tension is 35 - 40 cN; After winding forming, when the net weight of a single-spindle cheese is 15.5 kg, the measured value of the diameter of the cheese is 430 - 432 mm; When oiling with an oil nozzle, the concentration of the finishing agent is 10 wt%, and the oil content of the tow is 0.38 wt%.

Images