A method for producing crimped fibers

Abstract

This invention belongs to the field of chemical fiber production technology and relates to a method for producing crimped fibers. It employs a channel, a first guide roller with a baffle plate, and a second guide roller. The speed of the first guide roller is controlled at 4800-4900 m / min, consistent with the spinning speed, while the speed of the second guide roller is 4900-5000 m / min. Neither guide roller is actively heated. High-expansion nozzles are used to stretch the fibers, achieving high orientation and reducing their boiling water shrinkage rate. Simultaneously, the channel is equipped with a specially structured guide plate and air vents to guide turbulent airflow within the channel. This invention reduces the boiling water shrinkage rate of fibers without stretching or heat treatment, and also eliminates fiber bundle swaying or tension fluctuations caused by airflow disturbances. The resulting fibers have deep dyeing and good stability.

Description

Technical Field

[0001] This invention belongs to the field of chemical fiber production technology and relates to a method for producing crimped fibers. Background Technology

[0002] HOY fiber, or highly oriented fiber, possesses a stable internal structure and good uniformity. It has a high degree of orientation, with sufficient orientation in the crystalline regions but a lower degree of orientation in the amorphous regions. This characteristic makes it easier to absorb dye and dye more evenly than FDY fiber during the dyeing process. At the same time, HOY fiber has lower breaking strength, higher breaking elongation, lower boiling water shrinkage, and excellent softness compared to conventional FDY fiber. It can be used directly for weaving. When compounded with bicomponents such as T400, it can also exhibit good crimping effect. Furthermore, production efficiency can be improved by increasing the spinning speed to over 5000m / min.

[0003] In the prior art, the production of HOY fiber usually requires stretching and heat treatment of the fiber to promote fiber crystallization and shape, thereby reducing the boiling water shrinkage rate of the fiber. For example, patent application CN112281240A produces hollow crimped HOY fiber by using a spinneret with a 2C+2C shape design, a ring blowing cooling method, and setting process parameters such as a draw ratio of 2.0-2.5 and a winding speed of 5200-5600m / min. The literature (Production process of super soft dyed imitation HOY 83dtex / 144f polyester fully drawn yarn [J]. Synthetic Fiber, 2024, 53 (3):7-9.) reduces its boiling water shrinkage rate by heat-treating the fiber by heating the second hot roller to 120°C.

[0004] However, while stretching and heat treatment processes reduce fiber boiling water shrinkage, they also significantly impact fiber crimp properties, leading to a series of problems. First, stretching alters the fiber's supramolecular structure, causing macromolecules to align highly axially. While this increases strength, it often sacrifices crimp elasticity and bulkiness. For example, in stretching deformation processes, excessively high stretch ratios can reduce fiber crimp, resulting in finer crimps and affecting the final fabric's fluffy feel. Second, while heat treatment (such as heat setting) stabilizes fiber morphology, improper temperature control can solidify structures unfavorable to crimp development, leading to poor fiber crimp characteristics and lighter dyeing in subsequent processes. In addition, these processes also bring other drawbacks: the fibers are first oiled and bundled before being treated by the guide and hot roller. The oil is easy to decompose at high temperatures, and the moisture inside the fibers evaporates, resulting in a large amount of static electricity in subsequent processing, which often requires oiling again to solve the problem. When using roller heating, extremely high temperatures are often required to achieve the desired shaping effect, and the stability of the yarn path on the roller is poor, which easily causes fluctuations in various product indicators and makes them unstable.

[0005] Therefore, given that stretching and heat treatment, while optimizing fiber dimensional stability, also restrict its core crimping properties and are accompanied by issues such as dyeing, static electricity, and production stability, it is particularly necessary to develop a fiber with excellent crimping properties that can achieve low boiling water shrinkage without relying on complex post-stretching and high-temperature heat treatment. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art and to provide a method for producing crimped fibers.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for producing crimped fibers using the HOY process, employing an apparatus including a spinneret, a duct, a first guide roller, and a second guide roller. The duct is divided into upper and lower sections: the upper section is the spinning duct, and the lower section is the winding duct. Both the first and second guide rollers are equipped with baffles to block airflow and prevent it from affecting the yarn path. The spinning speed is the same as the speed of the first guide roller, which is 4800-4900 m / min, and the speed of the second guide roller is 4900-5000 m / min. Neither the first nor the second guide roller is actively heated.

[0009] Unlike existing technologies, this invention controls the speed of the first guide roller to be close to that of the second guide roller, so that the fiber is almost unstretched between the two rollers. At the same time, this invention controls the first and second guide rollers to not be actively heated, so that the fiber does not undergo heat treatment. However, this invention can still reduce the boiling water shrinkage rate of the fiber to a certain extent because the spinning speed of this invention is fast, and the melt extruded by the spinneret during the spinning process can be stretched far beyond the conventional ratio (called high-ratio spinneret stretching). High-ratio spinneret stretching can make the fiber highly oriented, thereby significantly reducing the boiling water shrinkage rate of the fiber.

[0010] However, due to the high spinning speed, each monofilament generates a strong self-carrying airflow due to its rapid movement. When multiple monofilaments are bundled together to form a filament bundle, the interaction between the filaments further intensifies the airflow, resulting in a significantly higher pressure in the outer region of the filament bundle than in the central region, forming a significant radial pressure difference. This pressure difference drives the airflow to accelerate downwards along the direction of the filament bundle movement. Especially when there are more than 24 filament bundles in the channel at the same time, the superposition effect of multiple airflows will cause severe turbulence in the flow state. A large amount of airflow will pass through the channel along the downward path of the filament bundle and impact the guide roller area, ultimately causing filament bundle swaying or tension fluctuations. Although the influence of transverse rotating airflow can be weakened by adding a baffle plate to the guide roller, this measure has limited effect on suppressing axial downward airflow and cannot completely eliminate the interference of airflow disturbance on the stability of the filament bundle. Therefore, this invention proposes the following solution:

[0011] The same spinning station shares a common passageway. All the spinnerets on the same spinning station are arranged in a straight line. The direction of this straight line is called the left-right direction. The horizontal direction perpendicular to the left-right direction is called the front-back direction. The vertical plane of this straight line is called plane X.

[0012] The passageway includes two symmetrically distributed sidewalls on the front and rear sides of surface X, referred to as the front sidewall and the rear sidewall, respectively. Inside the passageway are two sets of guide vanes, distributed on the front and rear sides of surface X. Several guide vanes in the same set are arranged at intervals from top to bottom, with the end of each guide vane closer to surface X higher than the end farther from surface X. The end of each guide vane farther from surface X is fixedly connected to the front or rear sidewall of the passageway. The two sets of guide vanes are staggered vertically. The front and rear sidewalls of the passageway have air outlets corresponding to each guide vane, used to discharge the airflow guided by each guide vane. When this passageway is used, the airflow is discharged through the passageway by the guide vanes, greatly reducing the airflow rate exiting the passageway.

[0013] As a preferred technical solution:

[0014] In the above-described method for producing crimped fibers, the angle between the guide plate fixedly connected to the front side wall of the tunnel and the front side wall of the tunnel is α1, and the angle between the guide plate fixedly connected to the rear side wall of the tunnel and the rear side wall of the tunnel is α2, where α1 is 30-45° and α2 is 30-45°.

[0015] In the method for producing crimped fibers as described above, the front and rear sidewalls of the channel are both parallel to plane X.

[0016] In the above-described method for producing crimped fibers, the distance between the front and rear sidewalls of the channel is d, the distance between the guide plate fixedly connected to the front sidewall of the channel and surface X is d1, and the distance between the guide plate fixedly connected to the rear sidewall of the channel and surface X is d2. d is 68-72cm, d1 is 2.94%-3.74% of d, and d2 is 2.94%-3.74% of d.

[0017] In the above-described method for producing crimped fibers, the front and rear side walls of the passage are both inverted isosceles trapezoidal vertical plates, which are connected by two rectangular inclined plates. The upper base of the inverted isosceles trapezoidal vertical plate is Lu, the lower base is Ld, and the height is h, where Ld > Lu, Lu is 28-32cm, Ld is 145-155cm, and h is 500cm.

[0018] In the above-described method for producing crimped fibers, the intersection line between the guide plate fixedly connected to the front sidewall of the tunnel and the front sidewall of the tunnel is denoted as the front intersection line group. The distance between the front intersection line group and the left side of the front sidewall of the tunnel is d3, the distance between the front intersection line group and the right side of the front sidewall of the tunnel is d4, the distance between the front intersection line group and the upper edge of the front sidewall of the tunnel is d5, the distance between the front intersection line group and the lower edge of the front sidewall of the tunnel is d6, and the distance between two adjacent intersection lines within the front intersection line group is d7. d3 is 0%-3.5% of Lu, d4 is 0%-3.5% of Lu, d5 is 14%-16% of h, d6 is 2.8%-7.2% of h, and d7 is 9.6%-10.4% of h.

[0019] In the above-described method for producing crimped fibers, the air vent is a rectangular hole, with one set of opposite sides parallel to the left and right directions and the other set of opposite sides parallel to the vertical direction.

[0020] On the front sidewall of the passage, the air outlet is located above the corresponding guide plate and the two are of the same length. The distance between the lower edge of the air outlet and the corresponding guide plate is d13, and the distance between the upper edge of the air outlet and the corresponding guide plate is d14. d13 is 40%-48.9% of d7, and d14 is 44.4%-53.3% of d7.

[0021] The spatial configuration of the guide plate and air outlet on the rear wall of the tunnel is denoted as spatial configuration A. Taking the guide plate and air outlet on the front wall of the tunnel as the reference prototype, the spatial configuration formed by vertically moving the entire structure downward by d17 and simultaneously narrowing it from the left and right sides towards the middle is denoted as spatial configuration B. Spatial configuration A and spatial configuration B are symmetrical about plane X. d17 is 46.7%-55.6% of d7. The purpose of narrowing it from the left and right sides towards the middle is to make the distance between the guide plate and air outlet on the rear wall of the tunnel and the left side of the rear wall of the tunnel both d3, and the distance between the guide plate and air outlet on the rear wall of the tunnel and the right side of the rear wall of the tunnel both d4.

[0022] In the above-described method for producing crimped fibers, the roughness of the first guide roller and the second guide roller is 0.4-0.5 μm.

[0023] In the above-described method for producing crimped fibers, the circumference of the first or second guide roller is 78.54-81.68 cm, and the winding length of the filament bundle on the first or second guide roller is 38%-42% of its circumference. This design helps to reduce the phenomenon of entanglement on the roller.

[0024] In the above-described method for producing crimped fibers, the spinneret has a figure-eight shaped spinneret hole composed of two annular rings. Each annular ring has two opposing notches. The center distance between the two annular rings is 1-1.05 mm. The outer diameter of each annular ring is 0.9-1.1 mm and the inner diameter is 0.7-0.8 mm. The width of each notch is 0.09-0.11 mm.

[0025] The production method of crimped fiber as described in any of the above items has the following overall process flow: polyester melt → metering pump → spinning assembly → ring blowing cooling → bundling oiling → pre-networking → first guide roller → second guide roller → winding and forming.

[0026] The production method of crimped fiber as described above includes the following process parameters: length of the windless zone 50-60mm, cooling air pressure 23-27Pa, distance between the spinneret and the bundling oiling device 900-1100mm, pre-network pressure 0.03-0.05MPa, and winding speed 5100-5200m / min.

[0027] The method for producing crimped fibers as described above specifies that the crimped fibers have the following characteristics: 75-83 dtex / 36f, breaking strength ≥3.5 cN / dtex, breaking elongation 63.4%-64.8%, boiling water shrinkage 4.8%-5.2%, evenness (CV) ≤0.86%, oil content 0.38%-0.42%, and crimp degree (a measure of fiber crimp, expressed as the difference between the straightened length L and the crimped length L0 of the crimped fiber, expressed as L-L0). The percentage of L (expressed as a percentage) is 15.6%-18%, the downgrading rate of filaments is ≤0.71%, the number of breaks is ≤4.9 times / 24 hours·18 units, the coefficient of variation of breaking strength (CV) is ≤3.21%, and the coefficient of variation of breaking elongation is ≤4.92%. Based on the number of breaks, the coefficient of variation of breaking strength (CV), and the coefficient of variation of breaking elongation (CV), it can be seen that the present invention can avoid causing swaying or tension fluctuations in the transmission of filament bundles. In addition, the crimped fibers of the present invention are dyed more deeply in the subsequent process, which can be judged by shaking the socks for dyeing.

[0028] Beneficial effects:

[0029] (1) The present invention can reduce the boiling water shrinkage rate of fibers without stretching and heat treatment, avoiding the problems of light dyeing and poor crimping characteristics of fibers caused by stretching and heat treatment. It also avoids the situation where the oil decomposes at high temperature and the moisture in the fiber evaporates, and the large static electricity in the later processing requires re-oiling, which is caused by the fiber being first oiled and bundled and then guided and heat treated. It also avoids the problem of unstable product indicators caused by the poor stability of the heating roller yarn path.

[0030] (2) By setting a guide plate with a specific structure and matching air outlet in the channel, the present invention can discharge the turbulent airflow in the channel, greatly reduce the airflow from the channel opening, effectively eliminate the interference of airflow disturbance on the stability of the yarn bundle when the spinning speed is fast, and avoid causing yarn bundle transmission swaying or tension fluctuation.

[0031] (3) The crimped fiber prepared by the present invention has a deeper dyeing process and can effectively reduce the downgrading rate of the filaments and the number of breaks, thus ensuring the stability of the fiber's breaking strength and breaking elongation. Attached Figure Description

[0032] Figure 1 and Figure 2 This is a schematic diagram of the apparatus for producing crimped fibers according to the present invention. Figure 1 Main view, Figure 2 This is a side view;

[0033] Figure 3 This is a schematic diagram of the apparatus for producing crimped fibers in Comparative Example 1 (its tunnel is a conventional structure in the prior art);

[0034] Figure 4 This is a schematic diagram of the spinneret holes on the spinneret plate of the present invention;

[0035] Figure 5 A schematic diagram of d, d1, and d2;

[0036] Figure 6 A schematic diagram of Ld, Lu, h, d3, d4, d5, d6, d7, d13, and d14;

[0037] Among them, 1-spinning assembly, 2-channel, 21-spinning channel, 22-winding channel, 23-front sidewall of channel, 24-rear sidewall of channel, 3-first guide roller, 4-second guide roller, 5-bundling oiling device, 6-pre-networker, 7-guide plate, 8-air outlet, 9-wind baffle, 10-circular ring A, 11-circular ring B, 12-notch. Detailed Implementation

[0038] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0039] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0040] Intrinsic viscosity: According to GB / T 14190-2017 "Test Method for Fiber Grade Polyester (PET) Chips", the Ubbelohde viscometer is used to determine the viscosity. The sample is dissolved in a mixed solvent of phenol and tetrachloroethane (mass ratio of phenol to tetrachloroethane is 3:2). The outflow time of the solution in the Ubbelohde viscosity is measured. The relative viscosity is obtained by the ratio of the outflow time t of the sample solution to the outflow time t0 of the pure solvent. The F factor is found from the F factor table based on the relative viscosity. The intrinsic viscosity is obtained by dividing the F factor by the sample amount.

[0041] Linear density: According to GB / T 14343-2008 "Test method for linear density of chemical fiber filament", 20 parallel samples were taken, each sample with a length of 10,000 meters. The mass of each sample was measured and the linear density (dtex) of each sample was calculated.

[0042] Breaking strength, coefficient of variation (CV) of breaking strength, elongation at break, and coefficient of variation (CV) of elongation at break: Following GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments", the samples were tested using a fully automatic single-yarn tensile testing machine (model YG023B-Ⅱ). The specific procedure was as follows: First, the sample was conditioned for 4 hours in an environment with a temperature of 20℃ and a relative humidity of 65%. Then, it was clamped by upper and lower grippers with a clamping length of 500mm, and a pretension of 0.05cN / dtex was applied by a robotic arm to stabilize the sample. At the start of the test, the lower gripper stretched the sample uniformly at a speed of 500mm / min until the sample broke. Simultaneously, real-time data from the force sensor was recorded during the stretching process, and the relationship curve between strength and elongation was plotted using a data collection system. Finally, through data processing and analysis, the breaking strength, coefficient of variation (CV) of breaking strength, elongation at break, and coefficient of variation (CV) of elongation at break were obtained.

[0043] Boiling water shrinkage rate: The boiling water shrinkage rate of the samples was tested using the twisting method in GB / T 6505-2017 "Test Method for Heat Shrinkage Rate of Chemical Fiber Filaments (After Treatment)". The samples were treated with boiling water, and the sample length before and after boiling water treatment were measured simultaneously. The formula for calculating the boiling water shrinkage rate is as follows:

[0044] Boiling water shrinkage rate = (sample length before boiling water treatment - sample length after boiling water treatment) / sample length before boiling water treatment × 100.

[0045] Evenness coefficient (CV) value: The sample was tested using a USTER 5 evenness tester in accordance with GB / T 14346-2015 "Test Method for Evenness of Chemical Fiber Filaments - Capacitive Method". The specific procedure was as follows: the sample was first conditioned in an environment with a temperature of 20℃ and a humidity of 65% for 2 hours. Then, the sample was passed through the two plates of a capacitor at a uniform speed. The mass of the sample in each equal interval was converted into an electrical signal. The percentage of the standard deviation of all test electrical signals to the mean value was the evenness coefficient (CV) value. The test speed was 200 m / min and the test time for the sample was 2.5 min.

[0046] Oil content: According to GB / T 6504-2017 "Test Method for Oil Content of Chemical Fibers", approximately 2g of sample was weighed and tested using an MQC23-10 nuclear magnetic resonance oil content analyzer.

[0047] Curl degree: By visual observation and measuring the straightening length L and curl length L0 of the curled fiber with a ruler, the curl degree is obtained by calculation formula: Curl degree = (L-L0)×100% / L.

[0048] Downgrading rate of filaments: The downgrading of a silk cake is determined by whether there are more than 2 broken filaments on its surface. If there are more than 2, it is downgraded. The downgrading rate of filaments is then calculated using the following formula: Downgrading rate of filaments = Number of downgraded filaments × 100% / Total number of filaments.

[0049] Number of breakages: Breakage refers to the sudden breakage of a single filament or the entire filament bundle during the spinning process. Each breakage is counted as one breakage. The number of breakages in 18 spinning positions within 24 hours is calculated by averaging the data over a 10-day period.

[0050] An apparatus for producing crimped fibers, such as Figures 1-2 As shown, it includes a spinning assembly 1, a channel 2, a bundling and oiling device 5, a pre-networker 6, a first guide roller 3, and a second guide roller 4;

[0051] The passageway 2 is divided into two sections, the upper section being the spinning passageway 21 and the lower section being the winding passageway 22;

[0052] Both the first guide roller 3 and the second guide roller 4 are equipped with baffles 9 to block airflow and prevent airflow from affecting the silk path;

[0053] When using this device to produce crimped fibers, the same spinning station shares a common channel 2, and all the spinnerets on the same spinning station are arranged in a straight line. The direction of this straight line is called the left-right direction, the horizontal direction perpendicular to the left-right direction is called the front-back direction, and the vertical plane of this straight line is called plane X.

[0054] The passageway 2 includes two symmetrically distributed sidewalls on the front and rear sides of surface X, referred to as front sidewall 23 and rear sidewall 24, respectively. Both front sidewall 23 and rear sidewall 24 of the passageway 2 are parallel to surface X. The passageway 2 is equipped with two sets of guide plates 7, which are distributed on the front and rear sides of surface X. Several guide plates 7 in the same set are arranged at intervals from top to bottom. The end of each guide plate 7 closer to surface X is higher than the end away from surface X. The end of each guide plate 7 away from surface X is fixedly connected to the front sidewall 23 or rear sidewall 24 of the passageway 2. The two sets of guide plates 7 are staggered vertically. The front sidewall 23 and rear sidewall 24 of the passageway 2 are provided with air outlets 8, which correspond one-to-one with each guide plate 7 and are used to discharge the airflow guided by each guide plate 7. The air outlets 8 are rectangular holes, with one set of opposite sides parallel to the left and right directions and the other set of opposite sides parallel to the vertical direction.

[0055] The angle between the guide plate 7, which is fixedly connected to the front side wall 23 of the tunnel 2, and the front side wall 23 of the tunnel 2 is α1, and the angle between the guide plate 7, which is fixedly connected to the rear side wall 24 of the tunnel 2, and the rear side wall 24 of the tunnel 2 is α2.

[0056] like Figure 5 As shown, the distance between the front sidewall 23 and the rear sidewall 24 of the tunnel 2 is d. The distance between the guide plate 7 fixedly connected to the front sidewall 23 of the tunnel 2 and the surface X is d1. The distance between the guide plate 7 fixedly connected to the rear sidewall 24 of the tunnel 2 and the surface X is d2.

[0057] The front sidewall 23 and the rear sidewall 24 of the passageway 2 are both inverted isosceles trapezoidal vertical plates, which are connected by two rectangular inclined plates. The upper base of the inverted isosceles trapezoidal vertical plate is Lu, the lower base is Ld, and the height is h, where Ld>Lu.

[0058] like Figure 6 As shown, the intersection line between the guide plate 7, which is fixedly connected to the front side wall 23 of the tunnel 2, and the front side wall 23 of the tunnel 2 is called the front intersection line group. The distance between the front intersection line group and the left side of the front side wall 23 of the tunnel 2 is d3. The distance between the front intersection line group and the right side of the front side wall 23 of the tunnel 2 is d4. The distance between the front intersection line group and the upper edge of the front side wall 23 of the tunnel 2 is d5. The distance between the front intersection line group and the lower edge of the front side wall 23 of the tunnel 2 is d6. The distance between two adjacent intersection lines in the front intersection line group is d7.

[0059] On the front side wall 23 of the passageway 2, the air outlet 8 is located above the corresponding guide plate 7 and the two have the same length. The distance between the lower edge of the air outlet 8 and the corresponding guide plate 7 is d13, and the distance between the upper edge of the air outlet 8 and the corresponding guide plate 7 is d14.

[0060] The spatial configuration of the guide plate and air outlet on the rear wall of the tunnel is denoted as spatial configuration A. Taking the guide plate and air outlet on the front wall of the tunnel as the reference prototype, the spatial configuration formed by vertically moving the whole structure downward by d17 and simultaneously narrowing from the left and right sides towards the middle is denoted as spatial configuration B. Spatial configuration A and spatial configuration B are symmetrical about plane X. d17 is 46.7%-55.6% of d7. The purpose of narrowing from the left and right sides towards the middle is to make the distance between the guide plate and air outlet on the rear wall of the tunnel and the left side of the rear wall of the tunnel both d3, and the distance between the guide plate and air outlet on the rear wall of the tunnel and the right side of the rear wall of the tunnel both d4.

[0061] like Figure 4 As shown, the spinneret holes on the spinneret plate are in the shape of an "8", consisting of annular ring A 10 and annular ring B 11. Both annular ring A 10 and annular ring B 11 have two opposing notches 12.

[0062] like Figure 1 As shown, after the polyester melt is extruded from the spinning assembly 1 to form a filament bundle, it is first cooled by a ring blower, then oiled by the bundling and oiling device 5, and then enters the spinning channel 21 of the channel 2. Subsequently, it continues to be transported in the winding channel 22 of the channel 2. During the transport of the filament bundle in the channel 2, the airflow generated is guided by the guide plate 7 in the channel 2. Afterwards, these filament bundles converge at the pre-networker 6 to complete the pre-networking treatment. Then, they are transported and wound by the first guide roller 3 and the second guide roller 4 to finally obtain crimped fibers.

[0063] In the following embodiments, 24 bundles of yarn run simultaneously in the duct of the same spinning position.

[0064] Example 1

[0065] A method for producing crimped fibers, using the HOY process and the apparatus described above, with the overall process flow as follows: polyester melt (intrinsic viscosity of 0.625 dL / g) → metering pump → spinning assembly → ring blower cooling → bundling and oiling → pre-networking → first guide roller → second guide roller → winding and forming;

[0066] During the production process, neither the first guide roller nor the second guide roller is actively heated;

[0067] The relevant parameters of the device are as follows: the roughness of the first guide roller and the second guide roller are both 0.4 μm, and the circumference is 78.54 cm; α1 is 30°, α2 is 30°; d is 68 cm, d1 is 2.94% of d, d2 is 2.94% of d; Lu is 28 cm, Ld is 145 cm, h is 500 cm; d3 is 0% of Lu, d4 is 0% of Lu, d5 is 14% of h, d6 is 2.8% of h, d7 is 10.4% of h; d13 is 40% of d7, d14 is 44.4% of d7; d17 is 55.6% of d7; the center distance between annulus A and annulus B is 1 mm, the outer diameter of annulus A and annulus B is 0.9 mm, the inner diameter of annulus A and annulus B is 0.7 mm, and the width of the notch is 0.09 mm.

[0068] Relevant process parameters: length of the windless zone is 50mm, cooling air pressure is 23Pa, spinning speed is 4800m / min, distance between spinneret and bundle oiling device is 900mm, pre-network pressure is 0.03MPa, speed of the first guide roller is 4800m / min, winding length of the filament on the first guide roller is 38% of the circumference of the first guide roller, speed of the second guide roller is 4900m / min, winding length of the filament on the second guide roller is 38% of the circumference of the second guide roller, and winding speed is 5100m / min.

[0069] The final crimped fiber has the following specifications: 75 dtex / 36f, breaking strength: 3.64 cN / dtex, breaking elongation: 63.4%, boiling water shrinkage: 5.2%, evenness coefficient (CV): 0.84%, oil content: 0.38%, crimp: 15.6%, fuzz downgrading rate: 0.67%, breakage frequency: 4.9 times / 24 hours·18 units, breaking strength coefficient (CV): 3.21%, and breaking elongation coefficient (CV): 4.51%.

[0070] Comparative Example 1

[0071] A method for producing crimped fibers differs from Example 1 only in that the apparatus uses a conventional tunnel, with the structure as follows: Figure 3 As shown, the tunnel has no guide plate or air outlet, and the dimensions of the tunnel are the same as in Embodiment 1.

[0072] The final crimped fiber had a breaking strength of 3.61 cN / dtex, a breaking elongation of 63.7%, a filament degradation rate of 0.82%, a breakage frequency of 6.7 times / 24 hours·18 units, a breaking strength coefficient of variation (CV) of 4.69%, and a breaking elongation coefficient of variation (CV) of 6.71%.

[0073] Compared with Example 1, Comparative Example 1 shows an increase in the rate of filament downgrading, number of breakages, coefficient of variation (CV) of breaking strength, and coefficient of variation (CV) of breaking elongation. This is because at higher spinning speeds, the rapid movement of the fiber bundle generates a strong self-carrying airflow. However, the existing channel used in Comparative Example 1 lacks guide plates and air outlets, making it impossible to guide and discharge this airflow. A large amount of airflow will pass through the channel along the downward path of the fiber bundle and impact the guide roller area, ultimately causing the fiber bundle to sway or tension fluctuation. This directly leads to an increase in the number of filaments downgrading and the number of breakages. At the same time, the swaying of the fiber bundle on the guide roller caused by the airflow will cause uneven stress and heat distribution on the fiber, resulting in an increase in the coefficient of variation (CV) of breaking strength and the coefficient of variation (CV) of breaking elongation.

[0074] Comparative Example 2

[0075] A method for producing crimped fibers differs from Example 1 only in that: no guide plate and air outlet are provided on the rear side wall of the passage.

[0076] The final crimped fiber had a breaking strength of 3.65 cN / dtex, a breaking elongation of 63.2%, a filament degradation rate of 0.76%, a breakage frequency of 6.1 times / 24 hours·18 units, a breaking strength coefficient of variation (CV) of 4.28%, and a breaking elongation coefficient of variation (CV) of 5.84%.

[0077] Compared with Example 1, Comparative Example 2 shows an increase in the rate of filament downgrading, number of breaks, coefficient of variation (CV) of breaking strength, and coefficient of variation (CV) of breaking elongation. This is because when 24 bundles of filament move downwards simultaneously, a large self-carrying airflow is generated. However, Comparative Example 2 only has a guide plate and air outlet on the front side wall of the channel, and no corresponding structure is configured on the rear side wall, so it cannot exhaust all the airflow generated by the 24 bundles of filament. The residual airflow that is not exhausted will impact the guide roller area, causing the filament to sway or tension fluctuation. This directly leads to an increase in the number of filaments downgrading and the number of breaks. At the same time, the swaying of the filament on the guide roller caused by the airflow will cause uneven stress and heat on the fiber, which in turn causes an increase in the coefficient of variation (CV) of breaking strength and the coefficient of variation (CV) of breaking elongation.

[0078] Comparative Example 3

[0079] A method for producing crimped fibers differs from Example 1 only in that the guide plates and air outlets on the front and rear sidewalls of the tunnel are symmetrically distributed relative to surface X, and the positions and dimensions of the guide plates and air outlets on the front sidewall of the tunnel are the same as in Example 1.

[0080] The final crimped fiber had a breaking strength of 3.60 cN / dtex, a breaking elongation of 63.8%, a filament degradation rate of 0.75%, a breakage frequency of 5.8 times / 24 hours·18 units, a breaking strength coefficient of variation (CV) of 4.24%, and a breaking elongation coefficient of variation (CV) of 5.81%.

[0081] Compared with Example 1, Comparative Example 3 shows an increase in the rate of filament downgrading, number of breaks, coefficient of variation (CV) of breaking strength, and coefficient of variation (CV) of breaking elongation. This is because in Comparative Example 3, the guide plates and air outlets on the front and rear sidewalls of the channel are symmetrically distributed relative to surface X, rather than staggered vertically. Under this symmetrical layout, the two air outlets symmetrically guide the airflow, which will form vortices or backflow zones near the air outlets, causing airflow turbulence in the channel. This prevents the smooth flow of the self-carried airflow generated by the movement of the 24 bundles of fibers, thus causing the fiber bundles to sway or experience tension fluctuations. This directly leads to an increase in the number of filaments downgrading and the number of breaks. At the same time, the airflow turbulence causes the fiber bundles to sway more intensely on the guide rollers, resulting in uneven stress and heat distribution on the fibers, which in turn causes an increase in the coefficient of variation (CV) of breaking strength and the coefficient of variation (CV) of breaking elongation.

[0082] Example 2

[0083] A method for producing crimped fibers, using the HOY process and the apparatus described above, with the overall process flow as follows: polyester melt (intrinsic viscosity of 0.628 dL / g) → metering pump → spinning assembly → ring blower cooling → bundling and oiling → pre-networking → first guide roller → second guide roller → winding and forming;

[0084] During the production process, neither the first guide roller nor the second guide roller is actively heated;

[0085] The relevant parameters of the device are as follows: the roughness of the first guide roller and the second guide roller are both 0.5 μm, and the circumference is 81.68 cm; α1 is 35°, α2 is 35°; d is 70 cm, d1 is 3.15% of d, d2 is 3.15% of d; Lu is 30 cm, Ld is 150 cm, h is 500 cm; d3 is 2% of Lu, d4 is 2% of Lu, d5 is 15% of h, d6 is 5% of h, d7 is 10% of h; d13 is 42.3% of d7, d14 is 46.4% of d7; d17 is 53.6% of d7; the center distance between annulus A and annulus B is 1.05 mm, the outer diameter of annulus A and annulus B is 1 mm, the inner diameter of annulus A and annulus B is 0.75 mm, and the width of the notch is 0.1 mm.

[0086] Relevant process parameters: length of the windless zone is 55mm, cooling air pressure is 25Pa, spinning speed is 4830m / min, distance between spinneret and bundle oiling device is 950mm, pre-network pressure is 0.04MPa, speed of the first guide roller is 4830m / min, winding length of the filament on the first guide roller is 42% of the circumference of the first guide roller, speed of the second guide roller is 4930m / min, winding length of the filament on the second guide roller is 42% of the circumference of the second guide roller, and winding speed is 5130m / min.

[0087] The final crimped fiber has the following specifications: 79 dtex / 36f, tensile strength: 3.61 cN / dtex, elongation at break: 64%, boiling water shrinkage: 5%, evenness coefficient (CV): 0.86%, oil content: 0.39%, crimp: 17.9%, downgrade rate: 0.45%, breakage frequency: 4.8 times / 24 hours·18 units, coefficient of variation (CV) for tensile strength: 2.05%, and coefficient of variation (CV) for elongation at break: 4.03%.

[0088] Example 3

[0089] A method for producing crimped fibers, using the HOY process and the apparatus described above, with the overall process flow as follows: polyester melt (intrinsic viscosity of 0.635 dL / g) → metering pump → spinning assembly → ring blower cooling → bundling and oiling → pre-networking → first guide roller → second guide roller → winding and forming;

[0090] During the production process, neither the first guide roller nor the second guide roller is actively heated;

[0091] The relevant parameters of the device are as follows: the roughness of the first guide roller and the second guide roller are both 0.5 μm, and the circumference is 80.11 cm; α1 is 40°, α2 is 40°; d is 72 cm, d1 is 3.33% of d, d2 is 3.33% of d; Lu is 32 cm, Ld is 155 cm, h is 500 cm; d3 is 3.5% of Lu, d4 is 3.5% of Lu, d5 is 16% of h, d6 is 7.2% of h, d7 is 9.6% of h; d13 is 48.9% of d7, d14 is 53.3% of d7; d17 is 46.7% of d7; the center distance between annulus A and annulus B is 1 mm, the outer diameter of annulus A and annulus B is 1.1 mm, the inner diameter of annulus A and annulus B is 0.8 mm, and the width of the notch is 0.11 mm.

[0092] Relevant process parameters: length of the windless zone is 60mm, cooling air pressure is 27Pa, spinning speed is 4850m / min, distance between spinneret and bundle oiling device is 1000mm, pre-network pressure is 0.05MPa, speed of the first guide roller is 4850m / min, winding length of the filament on the first guide roller is 41% of the circumference of the first guide roller, speed of the second guide roller is 4950m / min, winding length of the filament on the second guide roller is 41% of the circumference of the second guide roller, and winding speed is 5150m / min.

[0093] The final crimped fiber has the following specifications: 80 dtex / 36f, breaking strength: 3.69 cN / dtex, breaking elongation: 63.9%, boiling water shrinkage: 4.9%, evenness coefficient (CV): 0.79%, oil content: 0.4%, crimp: 16.7%, fuzz downgrading rate: 0.71%, breakage frequency: 4.6 times / 24 hours·18 units, breaking strength coefficient (CV): 1.89%, and breaking elongation coefficient (CV): 3.64%.

[0094] Example 4

[0095] A method for producing crimped fibers, using the HOY process and the apparatus described above, with the overall process flow as follows: polyester melt (intrinsic viscosity of 0.63 dL / g) → metering pump → spinning assembly → ring blower cooling → bundling and oiling → pre-networking → first guide roller → second guide roller → winding and forming;

[0096] During the production process, neither the first guide roller nor the second guide roller is actively heated;

[0097] The relevant parameters of the device are as follows: the roughness of the first guide roller and the second guide roller are both 0.45 μm, and the circumference is 81.68 cm; α1 is 45°, α2 is 45°; d is 70 cm, d1 is 3.74% of d, d2 is 3.74% of d; Lu is 30 cm, Ld is 150 cm, h is 500 cm; d3 is 3% of Lu, d4 is 3% of Lu, d5 is 15% of h, d6 is 5% of h, d7 is 10% of h; d13 is 45.1% of d7, d14 is 49.3% of d7; d17 is 50.7% of d7; the center distance between annulus A and annulus B is 1.05 mm, the outer diameter of annulus A and annulus B is 1 mm, the inner diameter of annulus A and annulus B is 0.75 mm, and the width of the notch is 0.1 mm.

[0098] Relevant process parameters: length of the windless zone is 55mm, cooling air pressure is 26Pa, spinning speed is 4870m / min, distance between spinneret and bundle oiling device is 1050mm, pre-network pressure is 0.05MPa, speed of the first guide roller is 4870m / min, winding length of the filament on the first guide roller is 41% of the circumference of the first guide roller, speed of the second guide roller is 4970m / min, winding length of the filament on the second guide roller is 41% of the circumference of the second guide roller, and winding speed is 5170m / min.

[0099] The final crimped fiber has the following specifications: 83 dtex / 36f, tensile strength: 3.57 cN / dtex, elongation at break: 64.1%, boiling water shrinkage: 4.9%, evenness coefficient (CV): 0.81%, oil content: 0.4%, crimp: 18%, downgrade rate: 0.52%, breakage frequency: 4.7 times / 24 hours·18 units, coefficient of variation (CV) for tensile strength: 2.31%, and coefficient of variation (CV) for elongation at break: 4.67%.

[0100] Example 5

[0101] A method for producing crimped fibers, using the HOY process and the apparatus described above, with the overall process flow as follows: polyester melt (intrinsic viscosity of 0.629 dL / g) → metering pump → spinning assembly → ring blower cooling → bundling and oiling → pre-networking → first guide roller → second guide roller → winding and forming;

[0102] During the production process, neither the first guide roller nor the second guide roller is actively heated;

[0103] The relevant parameters of the device are as follows: the roughness of the first guide roller and the second guide roller are both 0.5 μm, and the circumference is 80.11 cm; α1 is 35°, α2 is 35°; d is 70 cm, d1 is 3.52% of d, d2 is 3.52% of d; Lu is 30 cm, Ld is 150 cm, h is 500 cm; d3 is 3% of Lu, d4 is 3% of Lu, d5 is 15% of h, d6 is 5% of h, d7 is 10% of h; d13 is 46.5% of d7, d14 is 50.7% of d7; d17 is 49.3% of d7; the center distance between annulus A and annulus B is 1 mm, the outer diameter of annulus A and annulus B is 1 mm, the inner diameter of annulus A and annulus B is 0.75 mm, and the width of the notch is 0.1 mm.

[0104] Relevant process parameters: length of the windless zone is 55mm, cooling air pressure is 25Pa, spinning speed is 4900m / min, distance between spinneret and bundle oiling device is 1100mm, pre-network pressure is 0.05MPa, speed of the first guide roller is 4900m / min, winding length of the filament on the first guide roller is 40% of the circumference of the first guide roller, speed of the second guide roller is 5000m / min, winding length of the filament on the second guide roller is 40% of the circumference of the second guide roller, and winding speed is 5200m / min.

[0105] The final crimped fiber has the following specifications: 75 dtex / 36f, breaking strength: 3.59 cN / dtex, breaking elongation: 64.8%, boiling water shrinkage: 4.8%, evenness coefficient (CV): 0.83%, oil content: 0.42%, crimp: 16.4%, fuzz downgrading rate: 0.63%, breakage frequency: 4.9 times / 24 hours·18 units, breaking strength coefficient (CV): 2.65%, and breaking elongation coefficient (CV): 4.92%.

Claims

1. A method for producing crimped fibers, employing the HOY process, wherein the apparatus includes a spinneret, a duct, a first guide roller, and a second guide roller, and both the first and second guide rollers are equipped with baffles, characterized in that... The spinning speed is the same as the speed of the first guide roller, which is 4800-4900 m / min, and the speed of the second guide roller is 4900-5000 m / min. Neither the first guide roller nor the second guide roller is actively heated. The same spinning station shares a common passageway. All the spinnerets on the same spinning station are arranged in a straight line. The direction of this straight line is called the left-right direction. The horizontal direction perpendicular to the left-right direction is called the front-back direction. The vertical plane of this straight line is called plane X. The passageway includes two symmetrically distributed sidewalls on the front and rear sides of surface X, referred to as the front sidewall and the rear sidewall, respectively. Inside the passageway, there are two sets of guide vanes, distributed on the front and rear sides of surface X. Several guide vanes in the same set are arranged at intervals from top to bottom, with the end of each guide vane closer to surface X higher than the end farther from surface X. The end of each guide vane farther from surface X is fixedly connected to the front or rear sidewall of the passageway. The two sets of guide vanes are staggered vertically. The front and rear sidewalls of the passageway are provided with air outlets that correspond one-to-one with each guide vane and are used to discharge the airflow guided by each guide vane.

2. The method for producing crimped fibers according to claim 1, characterized in that, The angle between the guide plate fixedly connected to the front wall of the tunnel and the front wall of the tunnel is α1, and the angle between the guide plate fixedly connected to the rear wall of the tunnel and the rear wall of the tunnel is α2. α1 is 30-45° and α2 is 30-45°.

3. The method for producing crimped fibers according to claim 1, characterized in that, The front and rear sidewalls of the passageway are both parallel to plane X.

4. The method for producing crimped fibers according to claim 3, characterized in that, The distance between the front and rear sidewalls of the passage is d. The distance between the guide plate fixedly connected to the front sidewall of the passage and surface X is d1. The distance between the guide plate fixedly connected to the rear sidewall of the passage and surface X is d2. d is 68-72cm, d1 is 2.94%-3.74% of d, and d2 is 2.94%-3.74% of d.

5. The method for producing crimped fibers according to claim 3, characterized in that, The front and rear side walls of the passageway are both inverted isosceles trapezoidal vertical plates, which are connected by two rectangular inclined plates. The upper base of the inverted isosceles trapezoidal vertical plate is Lu, the lower base is Ld, and the height is h. Ld > Lu, Lu is 28-32cm, Ld is 145-155cm, and h is 500cm.

6. The method for producing crimped fibers according to claim 5, characterized in that, The intersection line between the guide plate fixedly connected to the front side wall of the tunnel and the front side wall of the tunnel is called the front intersection line group. The distance between the front intersection line group and the left side of the front side wall of the tunnel is d3, the distance between the front intersection line group and the right side of the front side wall of the tunnel is d4, the distance between the front intersection line group and the upper edge of the front side wall of the tunnel is d5, the distance between the front intersection line group and the lower edge of the front side wall of the tunnel is d6, and the distance between two adjacent intersection lines in the front intersection line group is d7. d3 is 0%-3.5% of Lu, d4 is 0%-3.5% of Lu, d5 is 14%-16% of h, d6 is 2.8%-7.2% of h, and d7 is 9.6%-10.4% of h.

7. A method for producing crimped fibers according to claim 6, characterized in that, The vent is a rectangular hole, with one set of opposite sides parallel to the left and right directions, and the other set of opposite sides parallel to the vertical direction; On the front sidewall of the passage, the air outlet is located above the corresponding guide plate and the two are of the same length. The distance between the lower edge of the air outlet and the corresponding guide plate is d13, and the distance between the upper edge of the air outlet and the corresponding guide plate is d14. d13 is 40%-48.9% of d7, and d14 is 44.4%-53.3% of d7. The spatial configuration of the guide plate and air outlet on the rear wall of the tunnel is denoted as spatial configuration A. Taking the guide plate and air outlet on the front wall of the tunnel as the reference prototype, the spatial configuration formed by vertically moving the entire structure downward by d17 and simultaneously narrowing it from the left and right sides towards the middle is denoted as spatial configuration B. Spatial configuration A and spatial configuration B are symmetrical about plane X. d17 is 46.7%-55.6% of d7. The purpose of narrowing it from the left and right sides towards the middle is to make the distance between the guide plate and air outlet on the rear wall of the tunnel and the left side of the rear wall of the tunnel both d3, and the distance between the guide plate and air outlet on the rear wall of the tunnel and the right side of the rear wall of the tunnel both d4.

8. The method for producing crimped fibers according to claim 1, characterized in that, The roughness of the first guide roller and the second guide roller is 0.4-0.5μm.

9. A method for producing crimped fibers according to claim 1, characterized in that, The winding length of the filament bundle on the first or second guide roller is 38%-42% of its circumference.

10. A method for producing crimped fibers according to claim 1, characterized in that, The spinneret has a figure-eight shaped nozzle, consisting of two rings. Each ring has two opposing notches. The center distance between the two rings is 1-1.05 mm. The outer diameter of each ring is 0.9-1.1 mm and the inner diameter is 0.7-0.8 mm. The width of each notch is 0.09-0.11 mm.

11. A method for producing crimped fibers according to any one of claims 1 to 10, characterized in that, The overall process flow is as follows: polyester melt → metering pump → spinning assembly → ring blower cooling → bundling and oiling → pre-networking → first guide roller → second guide roller → winding and forming.

12. The method for producing crimped fibers according to claim 11, characterized in that, The process parameters include: length of the windless zone 50-60mm, cooling air pressure 23-27Pa, distance between the spinneret and the bundle oiling device 900-1100mm, pre-network pressure 0.03-0.05MPa, and winding speed 5100-5200m / min.

13. A method for producing crimped fibers according to claim 12, characterized in that, The specifications of the crimped fiber are 75-83 dtex / 36f, with a breaking strength ≥3.5 cN / dtex, a breaking elongation of 63.4%-64.8%, a boiling water shrinkage rate of 4.8%-5.2%, a yarn evenness coefficient (CV) ≤0.86%, an oil content of 0.38%-0.42%, a crimp degree of 15.6%-18%, a fuzz downgrading rate ≤0.71%, a breakage count ≤4.9 times / 24 hours·18 units, a breaking strength coefficient of variation (CV) ≤3.21%, and a breaking elongation coefficient of variation (CV) ≤4.92%.

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