Manufacturing method of low-fluffing irregular fiber by polyester FDY process

Abstract

The objective of the present invention is to provide a method for producing low-fluff irregular fiber using a polyester FDY process. The present invention provides a method for producing low-fluff irregular fiber using a polyester FDY process. When producing irregular fiber in the FDY process, the horizontal or vertical position of the ceramic guide in the pre-interlacing guide frame is adjusted to maintain the vertical state of the yarn bundle in the pre-interlacer and optimize the vibration effect, thereby producing low-fluff irregular fiber. The irregular cross-section fiber described above can be controlled to a fluff rate of 0.35-0.65% for triangular irregular fiber, 0.85-1.25% for trilobal irregular fiber, and 0.5-0.85% for flat irregular fiber. The method of the present invention can suppress fluffing caused by yarn bundle vibration and collision with the pre-interlacer, reduce loop fluffing caused by entanglement and yarn breakage between single yarns, and prevent fluffing during the hot drawing process by uniformly dispersing the oil agent, thereby significantly improving the quality of irregular cross-section fiber products.

Description

[Technical Field]

[0001] The present invention belongs to the field of spinning processing technology, and relates to a method for producing a low-fluff irregular fiber by a polyester FDY process. [Background technology]

[0002] Modified cross-section fibers are fibers with a variety of cross-sectional shapes, such as triangular, trilobal, flat, and Y-shaped, that are produced using a nozzle with non-circular holes during spinning. Compared to circular cross-section fibers, the requirements for the processing process and manufacturing equipment are more stringent, and there is also the issue of fuzz being more likely to occur during the filament's travel.

[0003] In the polyester FDY process, a pre-interlacer is typically installed between the oiling unit and the heat roll. Its main function is to uniformly distribute the oil applied to the yarn across the surface of each single yarn, improving the yarn's cohesion and antistatic properties, enhancing spinnability, and suppressing loop fuzzing. As shown in Figure 1, the pre-interlacer 7 is attached to the pre-interlacing panel 10, which is equipped with upper and lower frames for securing the ceramic guides and a compressed air supply pipe for interlacing. The yarn is supported by the upper and lower ceramic guides, and is dispersed and vibrated by compressed air sprayed from the pre-interlacing nozzle, uniformly distributing the oil.

[0004] When manufacturing modified cross-section fibers, the pre-interlacer generates a large amount of fuzz, resulting in loop fuzz and marring the product's appearance. The main flaws of existing equipment are as follows: 1. Even if the spacing between the pre-interlacing ceramic guides is uniform (see Figures 1 and 2), if the guide passage width is larger than the yarn diameter, the upper and lower support positions will differ in angle as the yarn enters and exits the upper and lower ceramic guides. This prevents the yarn from maintaining a vertical position within the pre-interlacing passage. As a result, the tilted yarn collides with the pre-interlacer, generating fuzz. 2. The effectiveness of yarn vibration within the pre-interlacer depends on the passage size, nozzle structure, interlacing pressure, yarn tension, and vibration distance (spacing between the upper and lower ceramic guides). In existing equipment, the spacing between the upper and lower ceramic guides is fixed (see Figure 1), so pressure adjustment alone cannot achieve optimal vibration effectiveness. Insufficient pressure leads to uneven oil dispersion, reducing the adhesive strength between the individual yarns and making fuzz more likely to occur during the heat roll drawing process. Conversely, excessive pressure can cause entanglement and collision between the individual yarns, resulting in loop yarns and yarn breakage.

[0005] In other words, there is a strong demand for the development of a method to reduce the fuzz of modified cross-section fibers by adjusting the pre-interlace guide frame. Summary of the Invention

[0006] The objective of this invention is to solve the above-mentioned problems of the prior art and to provide a method for producing low-fuzz modified cross-section fibers using the polyester FDY process. Specifically, the conventional fixed, evenly spaced ceramic guides are modified to a structure with adjustable lateral positioning. The lateral spacing of the ceramic guides is dynamically adjusted depending on the fulcrum position when the yarn bundle passes through the ceramic guides, allowing the yarn bundle to maintain a vertical position within the pre-interlacer. Furthermore, the conventional upper and lower ceramic guides with fixed longitudinal spacing are modified to a structure with adjustable longitudinal spacing. The spacing between the upper and lower ceramic guides is adjusted according to the characteristics of the fiber type, optimizing the vibration effect of the yarn bundle in the poly interlacer. These methods successfully reduce fuzzing of modified cross-section fibers significantly.

[0007] In detail, the present invention selects the following solution. The method for producing low-fluffing irregular fiber using the polyester FDY process involves adjusting the horizontal or vertical position of the ceramic guide in the pre-interlacing guide frame when producing irregular fiber in the FDY process, thereby maintaining the vertical state of the yarn bundle in the pre-interlacer and optimizing the vibration effect, thereby producing low-fluffing irregular fiber. The modified cross-section fibers in the present invention refer to fibers with a triangular, trilobal, or flat cross section. The fluff rate can be controlled to 0.35-0.65% for triangular modified cross-section fibers, 0.85-1.25% for trilobal modified cross-section fibers, and 0.5-0.85% for flat modified cross-section fibers. It has been demonstrated that the method of the present invention significantly reduces the fluff rate of modified cross-section fibers compared to conventional techniques. The vibration of the yarn inside the pre-interlacer is detected by an optical fiber sensor. The optical fibers of the optical fiber sensor are divided into two groups, one directly in front of the pre-interlacer's yarn path (light-emitting optical fiber) and one directly behind it (light-receiving optical fiber), and both are arranged in a horizontal array on the horizontal symmetrical axis of the pre-interlacer. The diameter of the optical fiber is smaller than the diameter of the single yarn, ensuring complete blocking of the light from the light-emitting fiber during the vibration process of the single yarn. The optical fiber sensor detects the distance deviated to the left and right from the longitudinal center axis of the pre-interlacer's yarn path as all single yarns in the yarn bundle pass vertically from top to bottom along the horizontal symmetrical axis of the yarn path. The distance value from the longitudinal center axis of the pre-interlacer's yarn path is set to 0, with distances to the left being positive and distances to the right being negative. The computer's central processing unit collects the distance data, performs statistical calculations to calculate the discrete distribution CV value of the distance, and generates a time-distance curve based on the distance data. At the distances where the single yarn vibrates most to the left and to the right, horizontal upper and lower vibration limit lines are drawn, respectively, and a midline is drawn midway between the upper and lower vibration limit lines. Using the midline as the reference, a line shifted 20% downward from the upper vibration limit line is defined as the upper section line of the normal vibration interval, and a line shifted 20% upward from the lower vibration limit line is defined as the lower section line (horizontal line) of the normal vibration interval. Furthermore, using the midline as the reference, a line shifted 30% downward from the upper section line is defined as the upper deviation line, and a line shifted 30% upward from the lower section line is defined as the lower deviation line (horizontal line). When the time-distance curve appears consecutively in the area above the upper section line or below the lower section line within 2 ms, the entire area of ​​the curve within that time period is marked with a red rectangle and defined as a "long segment." If the curve appears continuously only in the area between the upper and lower deviation lines within 2 ms, the entire area of ​​the curve within that time period is marked with a red rectangle and defined as a "short segment." If the CV value of the discrete distance distribution is less than 3.5% (a small CV value indicates uniform vibration), the midline coincides with the longitudinal central axis of the pre-interlacer yarn passage (i.e., the value is 0), and no "long segments" or "short segments" occur in the time-distance curve (the yarn is located on the central axis of the pre-interlacer and maintained in a vertical state, the vibration is neither too much nor too little, and there is no intermittent vibration), it indicates that the yarn remains vertical within the pre-interlacer and achieves the optimal vibration effect. Multiple optical fibers are placed within the pre-interlaced yarn passage. The diameter of the optical fiber is designed to be smaller than the diameter of a single yarn, allowing for complete shielding of light emitted from the optical fiber during the vibration process of the single yarn. A photoelectric converter converts the light intensity received by the optical fiber into a voltage signal, which is then compared with a preset reference voltage signal in a comparator. If the detected voltage is below the reference value, it indicates the absence of a single yarn, and if it is above the reference value, it indicates the presence of a single yarn. A central processing unit generates a time-distance curve based on this signal and analyzes the shape of the curve to detect the inclination and vibration state of the yarn within the pre-interlacer. It then quantitatively evaluates the yarn vibration pattern. Based on the analysis results, the horizontal and vertical positions of the guide frame are adjusted to maintain the yarn in a vertical position within the pre-interlaced yarn passage, achieving optimal vibration effects. As a result, the fuzz generation rate of irregular cross-section fibers is significantly reduced compared to conventional processes.

[0008] Preferred embodiments of the present invention are described below.

[0009] In the method for producing low-fluff profile fibers using the polyester FDY process, the pre-interlacing guide frame includes a grooved frame, a ceramic guide, a positioning block, a presser plate, and screws I, and further includes slide grooves and screws II installed on both ends of the grooved frame. The ceramic guide and positioning block are mounted within the grooved frame and fixed by the presser plate and screws I. The ceramic guide and positioning block are alternately arranged in the order of one positioning block, one ceramic guide, the next positioning block, and the next ceramic guide, i.e., one ceramic guide is installed between two positioning blocks.

[0010] The grooved frame and the pre-interlacer are both arranged horizontally, and the pre-interlacer is fixed to the center of the pre-interlace panel.

[0011] The grooved frame is divided into two levels, upper and lower, with the upper grooved frame located above the pre-interlacer and the lower grooved frame located below the pre-interlacer.

[0012] The slide groove has an inwardly concave trapezoidal structure. Slide rails with a convex trapezoidal structure that matches the slide groove structure are installed on both the left and right sides of the pre-interlacing panel. The slide groove is fitted into the slide rail, and screws II secure the slide groove and slide rail together. The slide rails move the slide groove up and down to adjust the vertical distance between the upper and lower ceramic guides. One screw II is installed on each of the left and right ends of the grooved frame, and screw II includes a set screw and a handle. When the handle is turned clockwise by hand, the set screw connected to the handle moves inward into the slide groove, contacting and compressing the slide rail, fixing the vertical distance between the upper and lower ceramic guides.

[0013] If the distance coordinate corresponding to the midline of the time-distance curve is positive and fuzz occurs in the upper left corner of the pre-interlacer, it indicates that the yarn bundle is tilted counterclockwise and to the left as a whole in the pre-interlaced yarn path. In this case, the size of the upper positioning block should be adjusted to move the upper yarn bundle guide position to the right.

[0014] If the distance coordinate corresponding to the midline of the time-distance curve is positive and fuzz occurs in the lower left corner of the pre-interlacer, it indicates that the yarn bundle is tilted clockwise and to the left as a whole in the pre-interlacing path. In this case, the size of the lower positioning block should be adjusted to move the lower yarn bundle guide position to the right.

[0015] If the distance coordinate corresponding to the midline of the time-distance curve is negative and fuzz occurs in the lower right corner of the pre-interlacer, it indicates that the yarn bundle is tilted counterclockwise and to the right as a whole in the pre-interlaced yarn path. In this case, the size of the lower positioning block should be adjusted to move the lower yarn bundle guide position to the left.

[0016] If the distance coordinate corresponding to the midline of the time-distance curve is negative and fuzz occurs in the upper right corner of the pre-interlacer, it indicates that the yarn bundle is tilted clockwise and to the right as a whole in the pre-interlaced yarn path. In this case, the size of the upper positioning block should be adjusted to move the upper yarn bundle guide position to the left.

[0017] Based on the passage width of the ceramic guide and the contact point between the yarn and the guide, the minimum machining deviation of the positioning block width between the ceramic guides is 0.25 mm, that is, the minimum adjustment unit of the lateral guide position is 0.25 mm.

[0018] If a "long segment" appears on the curve, the yarn bundle is vibrating excessively, and the tangled and colliding yarns are likely to cause loop fluffing. In this case, the vertical distance between the upper and lower grooved frames should be reduced to increase the yarn bundle tension, shorten the vibration distance, and improve the vibration effect. The adjustment range is usually to move the upper and lower guide frames 1mm closer to each other.

[0019] If a "short segment" appears on the curve, it means that the vibration of the yarn bundle is insufficient, which can easily cause intermittent vibration of the single yarn, resulting in uneven oiling of the yarn and fuzzing during hot drawing. In this case, the vertical distance between the upper and lower grooved frames should be increased to reduce the tension and extend the vibration distance to improve the vibration effect. The adjustment width is usually 1mm between the upper and lower guide frames.

[0020] In the method for producing low fluff non-circular fibers by the polyester FDY process, the width of the positioning blocks is 3 to 5 mm, and the widths of the positioning blocks may be equal or different.

[0021] In the method for producing low-fluffing irregular fiber using the polyester FDY process, the ceramic guide installed in the upper grooved frame is "U-shaped" and the ceramic guide installed in the lower grooved frame is "fork-shaped" (these are parts well known in the industry).

[0022] In the manufacturing method of the low-fluffing irregular cross-section fiber by the polyester FDY process, the passage width of all ceramic guides is 1.5 mm, which is designed to be larger than the diameter of a normal irregular cross-section fiber.

[0023] In the manufacturing method of low-fluffing non-circular fibers by the polyester FDY process, the width of the "U-type" and "fork-type" ceramic guides in the lateral direction is 12 mm.

[0024] In the method for producing low-fluffing irregular fiber using the polyester FDY process, the surface of the slide rail and the inner surface of the slide groove are mirror-finished, allowing the slide groove to move smoothly up and down along the slide rail, and adjusting the vertical distance between the upper and lower ceramic guides.

[0025] In the manufacturing method of low fluff non-circular fiber by the polyester FDY process, a gap of 0.3~0.5mm is provided between the slide grooves and slide rails on each side to ensure smooth up and down movement.

[0026] In the manufacturing method of low fluff non-circular fiber by the polyester FDY process, a scale is marked in the area near the slide rail of the pre-interlaced panel, and marks are made at 60 mm above and below the horizontal symmetry axis of the pre-interlaced panel.

[0027] In the method for producing low-fluff irregular fibers by the polyester FDY process, the parameters of the FDY process are a winding speed of 3800 to 5300 m / min, a first roll speed of 2400 to 3980 m / min, a hot roll draw ratio of 1.1 to 1.6, a pre-interlacing pressure of 0.025 to 0.055 MPa, and an oil agent adhesion rate of 0.8 to 1.2%.

[0028] In the method for producing low-fluffing irregular fiber by the polyester FDY process, the sampling frequency of the optical fiber sensor is 100 kHz, that is, data is collected 100 times per 1 ms.

[0029] The method for producing low-fuzz irregular fiber using the polyester FDY process of the present invention can suppress the generation of fuzz caused by yarn bundle vibration and collision with the pre-interlacer by adjusting the horizontal and vertical positions of the pre-interlacing guide frame, reduce loop fuzz caused by tangles and yarn breakage between single yarns, and prevent fuzz during the hot drawing process by uniformly dispersing the oil agent, thereby significantly improving the quality of irregular cross-section fiber products. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a front view of a prior art pre-interlacing device. [Figure 2] FIG. 1 is a top view of a guide frame in a prior art pre-interlacing device. [Figure 3] FIG. 2 is a front view of the pre-interlacing device of the present invention. [Figure 4] FIG. 2 is a top view of a guide frame in a preinterlacing device according to the present invention. [Figure 5] FIG. 2 is a top view of the ceramic guide. [Figure 6] FIG. 2 is a front view of the ceramic guide. [Figure 7] FIG. 10 is a top view of the guide frame slide groove. [Figure 8] FIG. 10 is a perspective view of a guide frame slide groove. [Figure 9] FIG. 10 is a partial schematic diagram of an upper guide frame to be assembled into a pre-interlaced panel. [Figure 10] 1 is a schematic diagram of the state of pre-interlaced yarn and the yarn positioned at different fulcrums of the ceramic guide. FIG. [Figure 11] FIG. 1 is a schematic diagram of yarn vibration in a pre-interlacer. [Figure 12]FIG. 10 is a front view of the optical fiber disposed in the pre-interlacer. [Figure 13] FIG. 10 is a top view of an optical fiber arrangement disposed within a pre-interlacer. [Figure 14] FIG. 10 is a schematic diagram showing a state in which the yarn is tilted leftward and counterclockwise in the pre-interlaced yarn path. [Figure 15] 1 is a schematic diagram of a state in which the yarn is tilted clockwise and to the left in the pre-interlaced yarn path. FIG. [Figure 16] FIG. 10 is a schematic diagram of a state in which the yarn is tilted to the right and counterclockwise in the pre-interlaced yarn path. [Figure 17] 1 is a schematic diagram of a state in which the yarn is tilted clockwise and to the right in the pre-interlaced yarn path. FIG. [Figure 18] FIG. 1 is a time-distance curve showing a "long segment." [Figure 19] FIG. 1 is a time-distance curve showing a "short segment." DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not deviate from the gist of the invention. Furthermore, even if a person skilled in the art is permitted to modify the present invention in various ways after reading the contents of the present invention, such modifications are also limited within the scope of the claims of the present invention as equivalent forms of the present invention.

[0032] 3 to 9, the pre-interlacing device includes a pre-interlace panel 10, a pre-interlacer 7, and a pre-interlace guide frame. The pre-interlacer 7 is fixed to the center of the pre-interlace panel 10. The pre-interlacing guide frame is composed of a slotted frame, ceramic guide, positioning block 4, retaining plate 5, screw I6, and slide grooves 13 and screws II14 installed on both ends of the slotted frame. The slotted frame is divided into two sections, upper and lower. The upper slotted frame 11 is located above the pre-interlacer 7, and the lower slotted frame 12 is located below the pre-interlacer 7. Both are horizontally aligned with the pre-interlacer 7. The slide grooves 13 have a trapezoidal structure with an inwardly concave shape. Slide rails 8, each with a trapezoidal structure with an outwardly convex shape in contrast to the slide grooves 13, are installed vertically on both the left and right sides of the pre-interlacing panel 10. The slide grooves 13 are fitted into the slide rails 8 and fixed with screws II14. The surfaces of the slide rails 8 and the inner surfaces of the slide grooves 13 are smoothed, and a gap of 0.3 to 0.5 mm is provided between the slide grooves on each side, allowing the slide grooves 13 to move up and down along the slide rails 8 and allowing the vertical distance between the upper and lower guide rails to be adjusted. In the area near the slide rail 8 of the pre-interlace panel 10, a scale 9 is displayed at 60 mm above and below the horizontal axis of symmetry of the pre-interlace panel. The "U-shaped" ceramic guide 2 is mounted within the upper grooved frame 11, and the "fork-shaped" ceramic guide 3 is mounted within the lower grooved frame 12. The horizontal width of both the "U-shaped" and "fork-shaped" ceramic guides is 12 mm, and the passage width of all ceramic guides is 1.5 mm. The ceramic guides and positioning blocks 4 are mounted within the grooved frame and secured with a retaining plate 5 and screws 16. The ceramic guides and positioning blocks are arranged alternately in the order of one positioning block, one ceramic guide, the next positioning block, and the next ceramic guide. The width of the positioning blocks is 3 to 5 mm, and each block may be the same or different widths. The minimum machining deviation of the positioning block width is allowed to be 0.25 mm, which means the minimum left-right adjustment unit for the horizontal conductor position is 0.25 mm. As shown in Figures 10 to 13, in the pre-interlacer 7, the yarn 1 is blown by compressed air ejected from a nozzle 17, causing it to vibrate. The vibration of the yarn is detected by an optical fiber sensor. The optical fibers of the optical fiber sensor are divided into two groups, one directly in front of the pre-interlacer yarn path (light-emitting optical fiber 15) and one directly behind it (light-receiving optical fiber 16), and both are arranged in a horizontal array on the horizontal symmetrical axis of the pre-interlacer. The sampling frequency of the optical fiber sensor is 100 kHz, i.e., data is collected 100 times per ms. The diameter of the optical fiber is smaller than the diameter of a single yarn. The optical fiber sensor detects the distance deviated to the left and right from the longitudinal center axis 18 of the pre-interlacer yarn path as all single yarns in the yarn bundle pass vertically from top to bottom along the horizontal symmetrical axis of the yarn path. The distance value from the longitudinal center axis of the pre-interlacer yarn path is set to 0, with distances to the left being positive and distances to the right being negative. After collecting distance data, the computer's central processing unit calculates the discrete distance distribution CV value through statistical calculations and generates a time-distance curve based on the distance data. As shown in Figures 18 and 19, horizontal upper vibration limit lines 20 and lower vibration limit lines 21 are drawn at the distances at which the single yarn vibrates most to the left and the distances at which it vibrates most to the right, respectively, and a midline 19 is drawn in the middle between the upper vibration limit lines and the lower vibration limit lines. Using the midline as a reference, a line shifted 20% downward from the upper vibration limit line is defined as the upper section line 22 of the normal vibration interval, and a line shifted 20% upward from the lower vibration limit line is defined as the lower section line 23 (horizontal line) of the normal vibration interval. Furthermore, using the midline as a reference, a line shifted 30% downward from the upper section line is defined as the upper deviation line 24, and a line shifted 30% upward from the lower section line is defined as the lower deviation line 25 (horizontal line). If the time-distance curve appears continuously above the upper deviation line or below the lower deviation line within 2 ms, the entire curve area within that time period is marked with a red rectangle and defined as a "long segment" 26. If the curve appears continuously only in the area between the upper deviation line and the lower deviation line within 2 ms, the entire curve area within that time period is marked with a red rectangle and defined as a "short segment" 27. If the CV value of the discrete distance distribution is less than 3.5%, the midline coincides with the longitudinal central axis 18 of the pre-interlacer yarn passage, and no "long segments" or "short segments" occur in the time-distance curve, this indicates that the yarn remains vertical in the pre-interlacer and achieves the optimal vibration effect. If the distance coordinate corresponding to the midline of the time-distance curve is positive and fuzz occurs in the upper left corner of the pre-interlacer, it indicates that the yarn bundle is tilted counterclockwise and to the left overall in the pre-interlaced yarn path (Fig. 14). In this case, the size of the upper positioning block should be adjusted to move the upper yarn bundle guide position to the right. If the distance coordinate corresponding to the midline of the time-distance curve is positive and fuzz occurs in the lower left corner of the pre-interlacer, it indicates that the yarn bundle is tilted clockwise and to the left as a whole in the pre-interlacing path (Fig. 15). In this case, the size of the lower positioning block should be adjusted to move the lower yarn bundle guide position to the right. If the distance coordinate corresponding to the midline of the time-distance curve is negative and fuzz occurs in the lower right corner of the pre-interlacer, it indicates that the yarn bundle is tilted counterclockwise and to the right overall in the pre-interlaced yarn path (Fig. 16). In this case, the size of the lower positioning block should be adjusted to move the lower yarn bundle guide position to the left. If the distance coordinate corresponding to the midline of the time-distance curve is negative and fuzz occurs in the upper right corner of the pre-interlacer, it indicates that the yarn bundle is tilted clockwise and to the right overall in the pre-interlaced yarn path (Fig. 17). In this case, the size of the upper positioning block should be adjusted to move the upper yarn bundle guide position to the left. As shown in Figure 18, if a "long segment" appears on the curve, the yarn bundle is vibrating excessively, and the single yarns are likely to become tangled or collide, resulting in loop fluffing. In this case, the vertical distance between the upper and lower grooved frames should be reduced to increase the yarn bundle tension and shorten the vibration distance to improve the vibration effect. The adjustment width is usually to move the upper and lower guide frames 1 mm closer to each other. As shown in Figure 19, if a "short segment" appears on the curve, it indicates that the yarn bundle is not vibrating sufficiently, which can easily cause intermittent vibration of the single yarn, resulting in uneven oiling of the yarn and fuzzing during hot drawing. In this case, the vertical distance between the upper and lower grooved frames should be increased to reduce tension and extend the vibration distance to improve the vibration effect. The adjustment width is usually set to separate the upper and lower guide frames by 1 mm. The test method for the yarn rate in this invention is to test the yarn rate of irregular fibers according to the industry standard FZ / T 50054-2021 "Online intelligent inspection of chemical fiber filament package appearance".

[0033] Example 1 The method for producing low-fuzz trilobal fiber using the polyester FDY process uses the pre-interlacing device, with 12 ceramic guides on each of the upper and lower stages. When producing trilobal fiber using the FDY process, the horizontal and vertical positions of the ceramic guides on the pre-interlacing guide frame are adjusted while the yarn is running through the yarn path, thereby maintaining the yarn bundle vertical within the pre-interlacer and achieving an optimal vibration effect, thereby producing 55dtex / 72f trilobal fiber. The FDY process parameters are: winding speed 4900m / min, first roll speed 3875m / min, hot roll drawing ratio 1.32, pre-interlacing pressure 0.05MPa, oil adhesion rate 1.18%. When the yarn bundle is kept vertical in the pre-interlacer and the optimal vibration effect is achieved, the widths of the 1-13# positioning blocks between the upper "U-shaped" ceramic guides are 4.5mm, 4mm, 4mm, 4.25mm, 4mm, 4.25mm, 4mm, 3.75mm, 4mm, 3.5mm, 4mm, 4mm, 4.5mm, and the widths of the 1-13# positioning blocks between the lower "fork-shaped" ceramic guides are 3.5mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4.5mm, 4mm, 4.5mm, 4mm, 4.5mm, and the distance between the upper and lower ceramic guides is 82mm. The resulting trilobal non-woven fiber of 55 dtex / 72 f had a fluff rate of 1.03%.

[0034] Comparative Example 1 A method for manufacturing trilobal fiber using the polyester FDY process. The specific procedure is basically the same as in Example 1, except that the conventional pre-networking device shown in Figure 1 was used, the ceramic guide spacing between two adjacent spindles was fixed at 4 mm, and the distance between the upper and lower ceramic guides was fixed at 70 mm. The resulting 55dtex / 72f trilobal fiber had a fluff rate of 2.28%. The comparison with Example 1 showed that the fuzz rate was reduced by 1.25% in Example 1. This is because, when producing 55 dtex / 72 f trilobal cross-section fiber, the number of single fibers in the fiber is large and the specific surface area of ​​the cross-section is large. In conventional technology, however, it is necessary to increase the interlacing pressure to uniformly apply oil to the fiber. However, the increased pressure causes entanglement and collision between the single fibers, making fuzz more likely to occur. In the present invention, the distance between the upper and lower ceramic guides was adjusted from 70 mm to 82 mm, and the width of each positioning block was fine-tuned to improve the vibration effect of the yarn bundle, thereby successfully reducing the fuzz rate of the irregularly shaped fiber.

[0035] Example 2 The method for producing low-fuzz triangular irregular fiber using the polyester FDY process uses the pre-interlacing device, with 12 ceramic guides on each of the upper and lower stages.When producing trilobal irregular fiber using the FDY process, the horizontal and vertical positions of the ceramic guides on the pre-interlacing guide frame are adjusted while the yarn is running through the yarn path, thereby maintaining the yarn bundle vertical within the pre-interlacer and achieving an optimal vibration effect, thereby producing 53dtex / 36f triangular irregular fiber. The FDY process parameters are: winding speed 5000m / min, first roll speed 3650m / min, hot roll drawing ratio 1.39, pre-interlacing pressure 0.045MPa, oil adhesion rate 1.12%. When the yarn bundle is kept vertical in the pre-interlacer and the optimal vibration effect is achieved, the widths of the 1-13# positioning blocks between the upper "U-shaped" ceramic guides are 4.25mm, 4mm, 4mm, 4.5mm, 4mm, 4.25mm, 4mm, 3.5mm, 4mm, 3.75mm, 4mm, 4.25mm, and 4.25mm, respectively; the widths of the 1-13# positioning blocks between the lower "fork-shaped" ceramic guides are 3.75mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4.25mm, 4mm, 4.25mm, 4mm, 4.25mm, and 4.25mm, respectively; and the distance between the upper and lower ceramic guides is 58mm. The resulting triangular irregular fiber of 53 dtex / 36 f had a fluff rate of 0.55%.

[0036] Comparative Example 2 A method for manufacturing triangular irregular fiber using the polyester FDY process. The specific procedure is basically the same as in Example 2, except that the conventional pre-networking device shown in Figure 1 was used, the ceramic guide spacing between two adjacent spindles was fixed at 4 mm, and the distance between the upper and lower ceramic guides was fixed at 70 mm. The fluffing rate of the 53dtex / 36f triangular irregular fiber produced in this way was 1.60%. The comparison result with Example 2 shows that the fluff rate was reduced by 1.05% in Example 2. This was because, when producing 53 dtex / 36 f triangular cross-section fibers, the distance between the upper and lower ceramic guides was adjusted from 70 mm to 58 mm, and the width of each positioning block was fine-tuned to improve the vibration effect of the yarn bundle, thereby successfully reducing the fluff rate of the irregularly shaped fibers.

[0037] Example 3 The method for producing low-fuzz flat irregular fiber using the polyester FDY process uses the pre-interlacing device, with 12 ceramic guides on each of the upper and lower stages. When producing trilobal irregular fiber using the FDY process, the horizontal and vertical positions of the ceramic guides on the pre-interlacing guide frame are adjusted while the yarn is running through the yarn path, thereby maintaining the yarn bundle vertical within the pre-interlacer and achieving an optimal vibration effect, thereby producing 33dtex / 24f flat irregular fiber. The FDY process parameters are: winding speed 5200m / min, first roll speed 3850m / min, hot roll drawing ratio 1.38, pre-interlacing pressure 0.035MPa, oil adhesion rate 1.02%. When the yarn bundle is kept vertical in the pre-interlacer and the optimal vibration effect is achieved, the widths of the 1-13# positioning blocks between the upper "U-shaped" ceramic guides are 4mm, 4.25mm, 4mm, 4.5mm, 4.25mm, 4mm, 4mm, 3.75mm, 4mm, 3.75mm, 4mm, 4.25mm, and 4mm, respectively. The widths of the 1-13# positioning blocks between the lower "fork-shaped" ceramic guides are 3.5mm, 4mm, 4.25mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4mm, 4.25mm, 4mm, 4mm, 4.25mm, and 4.25mm, respectively. The distance between the upper and lower ceramic guides is 64mm. The obtained flat irregular fiber of 53 dtex / 36 f had a fluff rate of 0.67%.

[0038] Comparative Example 3 A method for manufacturing flat irregular fiber using the polyester FDY process. The specific procedure is basically the same as in Example 3, except that the conventional pre-networking device shown in Figure 1 was used, the ceramic guide spacing between two adjacent spindles was fixed at 4 mm, and the distance between the upper and lower ceramic guides was fixed at 70 mm. The fluffing rate of the 33dtex / 24f flat irregular fiber produced in this way was 2.01%. The comparison result with Example 3 shows that the fluff rate was reduced by 1.34% in Example 3. This was because, when producing 33 dtex / 24 f flat cross-section fibers, the distance between the upper and lower ceramic guides was adjusted from 70 mm to 64 mm, and the width of each positioning block was finely adjusted to improve the vibration effect of the yarn bundle, thereby successfully reducing the fluff rate of the irregularly shaped fibers. [Explanation of symbols]

[0039] 1 - yarn line, 2 - "U-shaped" ceramic guide, 3 - "fork-shaped" ceramic guide, 4 - positioning block, 5 - pressure plate, 6 - screw I, 7 - pre-interlacer, 8 - slide rail, 9 - scale, 10 - pre-interlacing panel, 11 - upper grooved frame, 12 - lower grooved frame, 13 - slide groove, 14 - screw II, 15 - light-emitting optical fiber, 16 - light-receiving optical fiber, 17 - nozzle, 18 - pre-interlacer yarn path longitudinal center axis, 19 - center line, 20 - upper vibration limit line, 21 - lower vibration limit line, 22 - upper section line, 23 - lower section line, 24 - upper deviation line, 25 - lower deviation line, 26 - long segment, 27 - short segment

Claims

1. When producing profiled fibers in the FDY process, the yarn bundle is kept vertical in the pre-interlacer by adjusting the horizontal or vertical position of the ceramic guide in the pre-interlace guide frame in the yarn transport path, achieving an optimal vibration effect and producing profiled fibers with low fluffing. the irregular fibers are triangular irregular fibers, trilobal irregular fibers or flat irregular fibers, and when the irregular fibers are triangular irregular fibers, the fluff rate is 0.35-0.65%, when the irregular fibers are trilobal irregular fibers, the fluff rate is 0.85-1.25%, and when the irregular fibers are flat irregular fibers, the fluff rate is 0.5-0.85%, The vibration status of the yarn bundle in the pre-interlacer is detected by an optical fiber sensor. The optical fiber sensor has two sets of optical fibers, one directly in front of the other directly behind the yarn passage of the pre-interlacer, and both are arranged in a horizontal array on the horizontal symmetrical axis of the pre-interlacer. The diameter of the optical fiber is smaller than the diameter of the single yarn. The optical fiber sensor detects the left and right distances that the single yarns deviate from the vertical center axis of the yarn passage of the pre-interlacer when all the single yarns in the yarn bundle pass the horizontal symmetrical axis of the yarn passage in a vertical direction from top to bottom. The distance value from the vertical center axis of the yarn passage of the pre-interlacer is set to 0, the distance to the left is set to a positive value, and the distance to the right is set to a negative value. The central processing unit of the computer samples the distance data and then statistically calculates the discrete distribution CV value of the distance. A time-distance curve is generated based on the data, and a horizontal upper vibration limit line and a horizontal lower vibration limit line are drawn at the distances at which the single yarn vibrates maximally to the left and the distances at which the single yarn vibrates maximally to the right, respectively. A median line is drawn based on the center between the upper vibration limit line and the lower vibration limit line. A line obtained by shifting the upper vibration limit line downward by 20% is defined as the upper section line of the normal vibration section, a line obtained by shifting the lower vibration limit line upward by 20% is defined as the lower section line of the normal vibration section, a line obtained by shifting the upper section line downward by 30% is defined as the upper deviation line, and a line obtained by shifting the lower section line upward by 30% is defined as the lower deviation line. When a region above the upper section line or a region below the lower section line appears for 2 ms on the time-distance curve, the entire region of the curve within this time period is defined as a "long segment." When a region between the upper deviation line and the lower deviation line appears for 2 ms on the curve, the entire region of the curve within this time period is defined as a "short segment." If the CV value of the discrete distance distribution is less than 3.5%, the midline overlaps with the longitudinal center axis of the yarn path of the pre-interlacer, and no "long segment" or "short segment" appears on the time-distance curve, it indicates that the yarn bundle is kept vertical in the pre-interlacer and has reached the optimum vibration effect. A method for producing low-fluff irregular fibers by a polyester FDY process, characterized by:

2. The pre-interlace guide frame includes a grooved frame, a ceramic guide, a positioning block, a holding plate, a screw I, and slide grooves and screws II installed on both ends of the grooved frame; The ceramic guide and positioning block are mounted in a grooved frame so as to be fixed by a retaining plate and screws I; The ceramic guides and the positioning blocks are arranged alternately, The grooved frame and pre-interlacer are both positioned horizontally, The pre-interlacer is fixed in the center of the pre-interlace panel. The grooved frame is divided into two sections, upper and lower, The upper grooved frame is located above the pre-interlacer, and the lower grooved frame is located below the pre-interlacer. The slide groove has a trapezoidal structure that is concave inward. The left and right sides of the pre-interlace panel are provided with slide rails, which are trapezoidal structures that protrude outward and engage with the slide grooves, respectively. The slide groove is engaged with the slide rail, and the slide groove and the slide rail are fixed together by a screw II. The slide groove is moved up and down along the slide rail, thereby adjusting the vertical distance between the upper and lower ceramic guides. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 1.

3. The width of the positioning block is 3 to 5 mm. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 2.

4. The ceramic guides mounted in the upper grooved frame are "U-shaped" and the ceramic guides mounted in the lower grooved frame are "fork-shaped". The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 2.

5. The width of the thread passage of all ceramic guides is 1.5 mm. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 4.

6. The lateral width of the "U-shaped" ceramic guide and the "fork-shaped" ceramic guide is 12 mm. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 5.

7. The surface of the slide rail and the inner surface of the slide groove are mirror-finished. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 2.

8. A gap of 0.3 to 0.5 mm is formed between the slide grooves and the slide rails on each side. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 2.

9. The area adjacent to the slide rail of the pre-interlaced panel is provided with a scale. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 2.

10. The winding speed is 3800 to 5300 m / min. The roll speed is 2400 to 3980 m / min. The hot roll stretching ratio is 1.1 to 1.6, The pre-interlacing pressure is 0.025 to 0.055 MPa. The oil adhesion rate is 0.8 to 1.2%. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 1.

11. The sampling frequency of the optical fiber sensor is 100 kHz. The method for producing low fluff non-circular fibers by the polyester FDY process according to claim 1.

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