Moisture-absorbing and sweat-releasing polyester fiber and preparation method therefor

Abstract

A moisture-absorbing and sweat-releasing polyester fiber and a preparation method therefor. A three-stage side-blown cooling process is used for cooling in the method, wherein in the first stage, the air speed is 0.45-0.60 m / s, and the cooling length is 10-40 cm; in the second stage, the air speed is 0.60-0.75 m / s, and the cooling length is 40-50 cm; and in the third stage, the air speed is 0.75-0.90 m / s, and the cooling length is 50-120 cm. The moisture-absorbing and sweat-releasing polyester fiber has a fineness of 500-965 dtex, a breaking strength of greater than or equal to 2.0 cN / dtex, a coefficient of variation (CV) of the breaking strength of less than or equal to 4.0%, an elongation at break of 128±3.0%, a CV of the elongation at break of less than or equal to 4.0%, a CV of yarn unevenness of less than or equal to 1.80%, and a degree of profile of greater than or equal to 44%. The method realizes uniform cooling, and the prepared moisture-absorbing and sweat-releasing polyester fiber has good quality.

Description

Moisture-absorbing and perspiration-releasing polyester fiber and preparation method thereof Technical Field

[0001] The invention belongs to the technical field of polyester melt spinning and relates to a moisture-absorbing and perspiration-releasing polyester fiber and a preparation method thereof. Background Art

[0002] With the continuous development of the economy, people's material life is improving day by day, and they pay more and more attention to the comfort and aesthetic quality of clothing when wearing. Although polyester fabrics have many advantages such as good hand feel, good drape and good wrinkle resistance, compared with cotton and linen, polyester is a hydrophobic fiber with a lack of hydrophilic groups in its macromolecules and poor hygroscopicity, which affects the wearing comfort of clothing and limits its application in the field of clothing. Moisture-absorbing and perspiration-wicking polyester fibers are basically modified by physical methods, that is, using a "cross" type spinneret to give the fabric higher water absorption and hydrophobicity, thereby improving the wearing comfort of polyester fabrics. However, the "cross" cross section has a large number of special-shaped holes, and the cooling method of the prior art adopts side-blowing cooling.

[0003] The current working process of cooling equipment is: air inlet through air duct → air inlet regulating valve → filtration → diversion chamber → rectification → static pressure chamber → side-blowing mesh plate outlet. Among them, the diversion chamber and the static pressure chamber are both single cavities, and the wind speed of the cooling air reaching the side-blowing mesh plate outlet is adjusted by a single air valve, so that the wind speed of the entire mesh plate is uniform and constant. However, the cross-shaped fibers have a relatively thick central axis where the horizontal and vertical bars of the cross section are connected and overlapped, and the cooling effect is inconsistent with other parts. At the same time, the specific surface area of ​​the "cross" cross-section fiber is large, and the cooling air should not be too large. Too much cooling air will cause the fiber to rotate and vibrate violently, resulting in abnormal nozzle stretching after the melt is extruded from the spinneret, and uneven fiber strips, so a low wind speed is required. However, low wind speeds can easily lead to localized airflow shortages, which not only prolongs the fiber cooling time and reduces its shape, thus affecting moisture wicking performance, but also easily leads to a skin-core structure, where the outer layer cools but the inner fiber does not. This can cause the moisture wicking polyester fiber produced to have uneven strength, uneven yarn length, and poor shape due to cooling issues. Furthermore, problems such as yarn breakage during post-processing are more likely to occur.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of uneven strength, uneven strands, poor shape and other problems of moisture-absorbing and perspiration-releasing polyester fibers in the prior art caused by cooling, and to provide a moisture-absorbing and perspiration-releasing polyester fiber and a preparation method thereof.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a moisture-wicking polyester fiber comprises: a polyester melt is sequentially metered, melt-extruded through a spinneret, cooled, oiled, and wound to produce the moisture-wicking polyester fiber; the spinneret has a "cross" cross-section spinneret; and a three-stage side-blowing cooling process is used for cooling. The three-stage process from top to bottom is specifically as follows:

[0008] In the first stage, the wind speed is 0.45-0.60 m / s, and the cooling length (height) is 10-40 cm. This stage is the state where the melt stream is stretched and before solidification. The fiber diameter gradually decreases from the maximum diameter in the windless zone (the puffing zone at the spinneret outlet) until the fiber diameter is basically stable. A slightly lower wind speed is used in this stage.

[0009] In the second stage, the wind speed is 0.60-0.75 m / s, and the cooling length (height) is 40-50 cm. This stage is the stage of melt stream solidification, also known as the deformation zone. At this wind speed, the intersection of the cross-section fibers of the cross fiber is cooled.

[0010] In the third section, the wind speed is 0.75-0.90 m / s, and the cooling length (height) is 50-120 cm. This stage is the main part for forming the linear density and fiber structure of the tow, and belongs to the solid-state tow stretching area, which has the greatest impact on the fiber orientation. By adopting a higher wind speed, the speed in this area rises rapidly, and through high-speed cooling, the crystallization rate is increased, which increases the fiber orientation degree, thereby improving the strength index of the "cross" cross-section fiber.

[0011] As the preferred technical solution:

[0012] In the method for preparing the moisture-absorbing and perspiration-releasing polyester fiber, the cooling air temperature of each section is equal, which is 22-23.5° C.; and the cooling humidity of each section is equal, which is 68-72%.

[0013] As described above, in a method for preparing a moisture-absorbing and perspiration-wicking polyester fiber, a three-stage side-blowing cooling process is achieved by dividing the static pressure chamber into three parts or designing three small static pressure chambers. Each part of the static pressure chamber or each small static pressure chamber is controlled by an independent air valve to control the inlet pressure and air volume. Each part of the static pressure chamber or each small static pressure chamber is equipped with a wind pressure test interface, so that the minimum design pressure of each part of the static pressure chamber or each static pressure chamber can be lower.

[0014] During cooling, the air valve is designed as three side-by-side valves, and the diversion air duct is designed as a three-channel diversion air duct. Each channel corresponds to an air valve to achieve separate adjustment and control of the air intake volume. An independent filtering device is installed at the inlet end of each of the three channels of the diversion air duct. After filtering, there are three independent diversion chambers, corresponding to three static pressure chambers respectively. The static pressure chambers correspond to the air outlet of the upper, middle and lower parts of the mesh plate respectively. The air outlet of the upper, middle and lower parts can be individually controlled by the air inlet valve.

[0015] In the preparation method of the moisture-absorbing and perspiration-wicking polyester fiber as described above, after the polyester melt is extruded through the spinneret, it passes through a windless zone before being cooled. The length (height) of the windless zone does not exceed 10 cm. The reason for setting the windless zone is that after the melt is extruded from the spinneret, due to the outlet expansion effect, the diameter of the filament bundle reaches the maximum when it exits the spinneret. If it is cooled directly, it is very easy to cause the melt to rupture, which eventually causes the spinning end to break.

[0016] As described above, in the method for preparing a moisture-absorbing and perspiration-wicking polyester fiber, the effective diameter of the spinneret (referring to the diameter of the circle where the outermost spinneret holes are located) is 80 to 90 mm; the length of the "cross" cross-section leaf of the spinneret hole is 0.5 to 0.6 mm, and the width is 0.05 to 0.15 mm; the length of the "cross" cross-section leaf of the spinneret hole is 0.3 to 0.4 mm, and the width is 0.05 to 0.15 mm.

[0017] In the above-mentioned method for preparing moisture-absorbing and perspiration-releasing polyester fibers, the number of spinneret holes is 192 to 288.

[0018] As described above, a method for preparing a moisture-absorbing and perspiration-wicking polyester fiber, the spinneret is composed of a spinneret area and a spinneret-free area (the spinneret-free area is solidly filled), all spinnerets are evenly distributed in a ring shape in the spinneret area, and the spinneret-free area is shaped like a "yuanbao", including a U-shaped area and a circular area located inside the U-shaped area, the center of the circular area coincides with the center of the spinneret, the U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment, the two vertical segments extend to the edge of the spinneret, the circular area is in contact with the inner wall of the arc segment, and the width of the vertical segment is the difference between the radii of the circles where the centers of the two adjacent circles of spinnerets are located.

[0019] The method for preparing a moisture-absorbing and perspiration-wicking polyester fiber as described above, wherein the diameter of the circular area inside the U-shaped area is 12 to 15 mm, the width of the vertical section is 10 to 12 mm, and the length is (spinneret diameter - circular area radius) / 2;

[0020] Because the number of holes is 192 to 288, the cooling effect of the melt stream away from the cooling air mesh plate is relatively poor, and the more holes there are, the smaller the air duct design area of ​​the spinneret without spinneret holes (this area is mainly used for the passage of cooling air, referred to as the air duct), resulting in a more limited cooling effect. The present invention improves the spinneret by designing a "yuanbao"-shaped area on the spinneret, which is not blocked by spinneret holes, thereby forming two air ducts without spinneret holes in the cooling area after the melt exits the spinneret holes. The length of the air duct at the near-wind end of the spinneret extends to the center area of ​​the spinneret to ensure that a sufficient amount of cooling air can enter; no air duct is provided at the far-wind end, and the cooling air entering the air duct is allowed to evenly pass through the spinneret hole distribution area at the far-wind end, thereby achieving the purpose of further improving the cooling effect.

[0021] In the method for preparing a moisture-wicking polyester fiber, a suspension of purified terephthalic acid (PTA), ethylene glycol (EG), and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension, and a polyester melt is obtained by esterification and polycondensation of the slurry suspension.

[0022] The molar ratio of ethylene glycol to purified terephthalic acid is 1.1 to 1.3:1;

[0023] The mass of the pentaerythritol suspension is 0.002-0.008% of the total mass of purified terephthalic acid and ethylene glycol;

[0024] The pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98.

[0025] In the preparation method of the moisture-absorbing and perspiration-releasing polyester fiber, the melt extrusion temperature is 288-292° C., the oil concentration is 11.5-12.5%, and the winding speed is 3000-3500 m / min.

[0026] The present invention also provides a moisture-absorbing and perspiration-wicking polyester fiber prepared by the method described in any one of the above items, wherein the moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 500 to 965 dtex, a breaking strength ≥2.0 cN / dtex, a breaking strength CV value ≤4.0%, an elongation at break 128±3.0%, an elongation at break CV value ≤4.0%, a yarn unevenness CV value ≤1.80%, and a degree of irregularity ≥44%.

[0027] Principle of the invention:

[0028] The present invention provides a method for preparing moisture-absorbing and perspiration-releasing polyester fibers. After the polyester melt is melt-extruded through a spinneret, a three-stage side-blowing cooling process is adopted. The first, second and third cooling stages are important transition stages for the initial transformation of the melt flow into nascent fibers, and are also the most important stages for spinning, forming and curing of the special shape.

[0029] The length of the three-stage cooling is related to the state of the melt stream at different stages, namely the diameter change zone, deformation zone and stretching zone. In the first stage, the melt stream is elongated and the diameter gradually decreases, which is the state of the reaction melt stream before it begins to solidify. The wind speed is 0.45m / s~0.60m / s to cool and shape the horizontal and vertical strips of the "cross" cross-section fiber to improve the fiber profile. If a high wind speed is used, although it can be quickly shaped and the profile is high, the sudden cooling of the tow after it is extruded from the high temperature is likely to cause melt rupture, resulting in breakage and poor spinnability. At the same time, it is to quench the melt stream after it exits the spinneret, with a high cooling rate, high tension in the spinneret stretching, and a large degree of pre-orientation of the fiber, resulting in a skin-core phenomenon in the fiber, which makes the cooling uniformity of the single tow poor and the coefficient of variation (CV value) of the fiber large. The wind speed at this stage is 0.45m / s to 0.60m / s, which is sufficient for the horizontal and vertical strips to cool and set, and has good spinnability. At the same time, it also reduces the situation where the fiber rotates and vibrates violently due to too high wind speed, resulting in abnormal stretching of the nozzle after the melt is extruded from the spinneret, uneven fiber dryness, etc.

[0030] The second stage is the transition stage from melt flow to nascent fiber. In this stage, the viscosity of melt flow increases rapidly, but the flow elongation speed slows down, and the spinning path length is short. Because the first stage uses a slightly lower wind speed to cool the horizontal and vertical strips, the second stage only cools the intersection of the "cross" cross-section fiber. The wind speed is 0.60m / s to 0.75m / s, so that the cooling effect of the whole fiber is consistent, there is no skin-core structure, and the quality problems of uneven strength, uneven strip length, and poor profile are reduced.

[0031] In the third stage, the diameter of the stream no longer changes, which belongs to the solid-state filament stretching area. The wind speed used in this stage is 0.75m / s~0.90m / s. In this area, the speed rises rapidly, and the crystallization rate is increased through high-speed cooling, which increases the fiber orientation and improves the strength index of the "cross" cross-section fiber.

[0032] In addition, most spinnerets in the prior art are arranged in a multi-ring circular pattern. After the melt is extruded and cooled to form, since each ring has a filament bundle, when it is cooled by side-blowing, the wind speed needs to pass through each filament bundle in the outer ring to cool the inner ring filament bundle, which is equivalent to having no air duct, resulting in different cooling effects for the inner and outer layers of filament bundles. However, the spinneret specially designed by the present invention, which has an "ingot"-shaped area without spinnerets, is installed so that the "ingot"-shaped opening is installed perpendicular to the cooling air mesh plate when the assembly is installed. After the melt is extruded and cooled to form, when it is cooled by side-blowing, the two spinneret-free air ducts, i.e., the center area without spinnerets, have no filament bundles to block the wind, and can converge in the center area and evenly pass through the spinneret distribution area at the far wind end, thereby achieving a better improvement in the cooling effect. Beneficial effects:

[0033] (1) The method for preparing moisture-absorbing and perspiration-wicking polyester fibers of the present invention has a simple process. Through three-stage cooling, the fiber cooling and forming process is linked to physical indicators, and fibers with a high degree of special shape are prepared, thereby improving the wicking efficiency of the fibers and subsequent fabrics, thereby improving moisture-absorbing and perspiration-wicking performance.

[0034] (2) The present invention further improves the cooling effect of the porous fiber by modifying the spinneret and setting a U-shaped area, and through three-stage cooling, the fiber physical indicators are more uniform, the unevenness of the strands is lower, and the crystallization and orientation are higher.

[0035] (3) The moisture-absorbing and perspiration-releasing polyester fiber prepared by the present invention has uniform physical indicators and a higher degree of special shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is a schematic diagram of the cooling process in the method for preparing a moisture-absorbing and perspiration-releasing polyester fiber of the present invention;

[0037] FIG2 is a cooling air duct used in the cooling process of the method for preparing a moisture-absorbing and perspiration-releasing polyester fiber of the present invention;

[0038] FIG3 is a spinneret used in the cooling process of the method for preparing a moisture-absorbing and perspiration-releasing polyester fiber of the present invention;

[0039] FIG4 is a schematic diagram of spinneret holes on a spinneret used in a cooling process in a method for preparing a moisture-absorbing and perspiration-releasing polyester fiber according to the present invention;

[0040] Among them, 1-air inlet duct, 2-air valve, 3-non-woven fabric, 4-diversion duct, 5-rectifier porous plate, 6-static pressure chamber, 7-screen plate, 8-wire window, 9-windless area, 10-spinneret, 11-filament bundle, 12-wire guide disk. DETAILED DESCRIPTION

[0041] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0042] The test methods for the performance indicators involved in the following embodiments are as follows:

[0043] (1) Breaking strength, breaking strength CV value, breaking elongation and breaking elongation CV value: According to the standard "Test method for tensile properties of chemical fiber filaments" (GB / T 14344-2022), the YG023B-Ⅱ fully automatic single yarn strength tester was used for testing. The specific steps are as follows:

[0044] (a) The sample was conditioned at a temperature of (20 ± 2)°C and a humidity of (65 ± 5)% for 4 h.

[0045] (b) The clamping length (500 ± 1.0 mm) is set by the upper and lower clamps. The manipulator clamps the specimen and applies a pretension (0.05 ± 0.005 cN / dtex). The test speed (500 mm / min) is set by the lower clamp.

[0046] (c) Stretch the specimen using a fully automatic single yarn strength tester until the specimen breaks;

[0047] (d) The force sensor draws a strength-elongation curve through the data collection system, and the breaking strength and breaking elongation are obtained through data processing. At the same time, after the test is completed, the fully automatic single yarn strength tester automatically calculates the coefficient of variation CV value of the breaking strength and the coefficient of variation CV value of the breaking elongation.

[0048] (2) CV value of yarn unevenness: According to the “Test method for yarn unevenness of chemical fiber filaments - capacitance method” (GB / T 14346-2015), the test was carried out using the USTER5 yarn unevenness meter. After the sample was humidified, the sample filament passed through the two electrodes of the capacitor at a uniform speed. The mass in each equal interval was converted into an electrical signal. The percentage of the standard deviation of all test electrical signals to the average value was the yarn unevenness. Among them, the test speed was 200 m / min, the test time was 2.5 min, the measuring tank and the tensioner were automatically selected, the twister was 12000 r / min, and the twisting was “S”.

[0049] (3) Shapedness: According to the Test Method for Shapedness of Chemical Fibers (FZ / T 50002-2013), the cross section of the fiber is magnified by a microscope, and the radius of the inscribed circle and the radius of the circumscribed circle in the fiber cross section are calculated. The shapedness is calculated according to the following formula: B = (1-r / R) * 100%

[0050] Where: B is the degree of irregularity, %; r is the radius of the inscribed circle, mm; R is the radius of the circumscribed circle, mm.

[0051] (4) 36-digit 24-hour hair degradation number: visual inspection.

[0052] (5) 36-digit 24-hour broken ends count: The operator records or the computer queries the equipment operation status.

[0053] In the embodiment of the present invention, the diameter of the spinneret used is 104 mm, and the effective diameter of the spinneret refers to the diameter of the circle where the outermost spinneret holes are located.

[0054] Example 1

[0055] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0056] (1) Preparation of polyester melt;

[0057] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.1:1; the mass of the pentaerythritol suspension is 0.004% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0058] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 260° C. and a pressure of 80 kPa, and to a second esterification reaction at a temperature of 268° C. and a pressure of 30 kPa to produce bis(hydroxyethyl) terephthalate;

[0059] (1.3) Pre-polycondensation of bis(hydroxyethyl) terephthalate was carried out at a temperature of 276°C in the upper polycondensation chamber and 278°C in the lower chamber, and at a pressure of 10 kPa in the upper chamber and 1.8 kPa in the lower chamber; and final polycondensation was carried out at a temperature of 282°C and a pressure of 210 Pa to produce a polyester melt;

[0060] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 288° C. through a spinneret having an effective diameter of 82 mm;

[0061] As shown in Figures 3 and 4, the spinneret 10 consists of a spinneret area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret 10. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret 10. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 13 mm, the width of the vertical segment is 10 mm, and the length is 48.75 mm. The spinnerets on the spinneret 10 are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.5 mm, and the width is 0.05 mm. The length of the "cross" cross-section leaf width of the spinneret is 0.3 mm, and the width is 0.05 mm. The number of spinnerets is 192.

[0062] (3) As shown in Figures 1 and 2, the product melt-extruded from the spinneret 10 in step (2) first passes through a windless zone 9 having a length of 1 cm, and then is cooled (i.e., a filament bundle 11 is obtained);

[0063] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is achieved by designing three small static pressure chambers 6. Each small static pressure chamber 6 is controlled by an independent air valve 2 to control the inlet pressure and air volume.

[0064] The cooling process is as follows: air inlet duct 1 → air valve 2 → non-woven fabric 3 inside diversion duct 4 → filtration → rectifier porous plate 5 → static pressure chamber 6 → side blowing mesh plate 7 → air outlet → silk window 8;

[0065] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.45m / s and the cooling length is 10cm; in the second stage, the wind speed is 0.6m / s and the cooling length is 40cm; in the third stage, the wind speed is 0.75m / s and the cooling length is 50cm; the cooling air temperature in each stage is the same, which is 22℃; the cooling humidity in each stage is the same, which is 68%;

[0066] (4) The product of step (3) was oiled at an oil concentration of 11.5%, and finally wound through the godet 12 of the winding device at 3000 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0067] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.03 cN / dtex, a breaking strength CV value of 1.62%, a breaking elongation of 128.4%, a breaking elongation CV value of 3.77%, a yarn unevenness CV value of 1.51%, a deformity of 48.4%, a 36-position 24-hour hair degradation number of 2, and a 36-position 24-hour broken end number of 1.

[0068] Comparative Example 1

[0069] A method for preparing a moisture-wicking polyester fiber is substantially the same as that of Example 1, except that step (3) does not employ a three-stage side-blowing cooling process, the diversion chamber and the static pressure chamber of the cooling method are both single cavities, the cooling wind speed is 0.65 m / s, and the cooling length is the sum of the three cooling lengths of Example 1;

[0070] The prepared moisture-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.01 cN / dtex, a breaking strength CV value of 5.78%, a breaking elongation of 132.4%, a breaking elongation CV value of 9.45%, a yarn unevenness CV value of 2.38%, a profile of 23.3%, a 36-bit 24-hour hair degradation number of 19, and a 36-bit 24-hour end breakage number of 45.

[0071] Comparing Comparative Example 1 with Example 1, it can be found that the CV values ​​of breaking strength, breaking elongation, yarn unevenness, 36-position 24-hour hairy yarn degradation, and 36-position 24-hour broken ends in Comparative Example 1 are significantly higher than those in Example 1, while the degree of irregularity is lower than that in Example 1. This is because the uniform wind speed of 0.65 m / s results in a small air volume, which prolongs the cooling time of the filament bundles and thus reduces the degree of irregularity. Furthermore, the low wind speed results in insufficient fiber cooling, resulting in uneven cooling and forming, which easily leads to the formation of a skin-core structure. This increases the CV values ​​of breaking strength, breaking elongation, and yarn unevenness. Furthermore, the spinneret, with an effective diameter of only 82 mm, has 192 holes. Due to the low cooling wind speed in Comparative Example 1, the filament bundles easily shake and collide with each other, resulting in hairy yarns and loose loops.

[0072] Example 2

[0073] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0074] (1) Preparation of polyester melt;

[0075] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.1:1; the mass of the pentaerythritol suspension is 0.002% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0076] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 261° C. and a pressure of 83 kPa, and to a second esterification reaction at a temperature of 268.5° C. and a pressure of 31 kPa to produce bis(hydroxyethyl) terephthalate;

[0077] (1.3) Pre-polycondensation of bis(hydroxyethyl) terephthalate was conducted at a temperature of 276.5°C in the upper polycondensation chamber and 278.4°C in the lower chamber, and at a pressure of 10.5 kPa in the upper chamber and 1.85 kPa in the lower chamber; and final polycondensation was conducted at a temperature of 282.4°C and a pressure of 213 Pa to produce a polyester melt;

[0078] (2) the polyester melt obtained in step (1) is first metered and then melt-extruded at 288.5° C. through a spinneret having an effective diameter of 80 mm;

[0079] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 12 mm, the width of the vertical segment is 10 mm, and the length is 49 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.51 mm, and the width is 0.06 mm. The length of the "cross" cross-section leaf of the spinneret is 0.31 mm, and the width is 0.06 mm. The number of spinnerets is 192.

[0080] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 2 cm, and then is cooled (i.e., a filament bundle is obtained);

[0081] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is designed by designing three small static pressure chambers. Each small static pressure chamber has an independent air valve to control the inlet pressure and air volume;

[0082] The specific process parameters for the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.45 m / s and the cooling length is 12 cm; in the second stage, the wind speed is 0.65 m / s and the cooling length is 45 cm; in the third stage, the wind speed is 0.8 m / s and the cooling length is 50 cm; the cooling air temperature in each stage is the same, at 22.2°C; and the cooling humidity in each stage is the same, at 68.5%.

[0083] (4) The product of step (3) was oiled at an oil concentration of 11.8%, and finally wound through a guide wire reel of a winding device at 3050 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0084] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.18 cN / dtex, a breaking strength CV value of 2.66%, an elongation at break of 128.4%, a breaking elongation CV value of 2.15%, a yarn unevenness CV value of 1.62%, a deformity of 60.1%, a 36-position 24-hour hair degradation number of 6, and a 36-position 24-hour broken end number of 1.

[0085] Example 3

[0086] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0087] (1) Preparation of polyester melt;

[0088] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.18:1; the mass of the pentaerythritol suspension is 0.003% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0089] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 262° C. and a pressure of 85 kPa, and to a second esterification reaction at a temperature of 269° C. and a pressure of 32 kPa to produce bis(hydroxyethyl) terephthalate;

[0090] (1.3) A pre-polycondensation reaction of bis(hydroxyethyl) terephthalate was conducted at a temperature of 277°C in the upper polycondensation chamber and 278.8°C in the lower chamber, and a pressure of 11 kPa in the upper chamber and 1.9 kPa in the lower chamber; a final polycondensation reaction was conducted at a temperature of 282.8°C and a pressure of 216 Pa to produce a polyester melt;

[0091] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 289° C. through a spinneret having an effective diameter of 83 mm;

[0092] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 14 mm, the width of the vertical segment is 10 mm, and the length is 48.5 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.52 mm, and the width is 0.07 mm. The length of the "cross" cross-section leaf of the spinneret is 0.32 mm, and the width is 0.07 mm. The number of spinnerets is 218.

[0093] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 3 cm, and then is cooled (i.e., a filament bundle is obtained);

[0094] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is designed by designing three small static pressure chambers. Each small static pressure chamber has an independent air valve to control the inlet pressure and air volume;

[0095] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.45m / s and the cooling length is 14cm; in the second stage, the wind speed is 0.7m / s and the cooling length is 45cm; in the third stage, the wind speed is 0.85m / s and the cooling length is 52cm; the cooling air temperature in each stage is the same, 22.3℃; the cooling humidity in each stage is the same, 69%;

[0096] (4) The product of step (3) was oiled at an oil concentration of 11.8%, and finally wound through a guide wire reel of a winding device at 3100 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0097] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 500 dtex, a breaking strength of 2.18 cN / dtex, a breaking strength CV value of 1.67%, a breaking elongation of 127.1%, a breaking elongation CV value of 1.19%, a yarn unevenness CV value of 1.49%, a deformity of 44.8%, a 36-position 24-hour hair degradation number of 1, and a 36-position 24-hour broken end number of 0.

[0098] Example 4

[0099] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0100] (1) Preparation of polyester melt;

[0101] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.18:1; the mass of the pentaerythritol suspension is 0.008% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0102] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 263° C. and a pressure of 88 kPa, and to a second esterification reaction at a temperature of 269.5° C. and a pressure of 33 kPa to produce bis(hydroxyethyl) terephthalate;

[0103] (1.3) Pre-polycondensation of bis(hydroxyethyl) terephthalate was carried out at a temperature of 277.5°C in the upper polycondensation chamber and 279°C in the lower chamber, and at a pressure of 11.5 kPa in the upper chamber and 1.95 kPa in the lower chamber; and final polycondensation was carried out at a temperature of 283°C and a pressure of 217 Pa to produce a polyester melt;

[0104] (2) the polyester melt obtained in step (1) is first metered and then melt-extruded at 289.5° C. through a spinneret having an effective diameter of 90 mm;

[0105] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 15 mm, the width of the vertical segment is 11 mm, and the length is 48.25 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.53 mm, and the width is 0.08 mm. The length of the "cross" cross-section leaf of the spinneret is 0.33 mm, and the width is 0.08 mm. The number of spinnerets is 288.

[0106] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 4 cm, and then is cooled (i.e., a filament bundle is obtained);

[0107] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process divides the static pressure chamber into three parts. Each part of the static pressure chamber is controlled by an independent air valve to control the inlet pressure and air volume.

[0108] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.5m / s and the cooling length is 15cm; in the second stage, the wind speed is 0.75m / s and the cooling length is 48cm; in the third stage, the wind speed is 0.85m / s and the cooling length is 60cm; the cooling air temperature in each stage is the same, 22.5℃; the cooling humidity in each stage is the same, 69.5%;

[0109] (4) The product of step (3) was oiled at an oil concentration of 11.8%, and finally wound through a guide wire reel of a winding device at 3150 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0110] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 965 dtex, a breaking strength of 2.15 cN / dtex, a breaking strength CV value of 1.77%, a breaking elongation of 128.5%, a breaking elongation CV value of 0.8%, a yarn unevenness CV value of 1.52%, a deformity of 44.1%, a 36-position 24-hour hair degradation number of 1, and a 36-position 24-hour broken end number of 4.

[0111] Example 5

[0112] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0113] (1) Preparation of polyester melt;

[0114] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.18:1; the mass of the pentaerythritol suspension is 0.006% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0115] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 264° C. and a pressure of 90 kPa, and to a second esterification reaction at a temperature of 270° C. and a pressure of 34 kPa to produce bis(hydroxyethyl) terephthalate;

[0116] (1.3) A pre-polycondensation reaction of bis(hydroxyethyl) terephthalate was conducted at a temperature of 278°C in the upper polycondensation chamber and 279.5°C in the lower chamber, and a pressure of 12 kPa in the upper chamber and 2 kPa in the lower chamber; a final polycondensation reaction was conducted at a temperature of 283.3°C and a pressure of 218 Pa to produce a polyester melt;

[0117] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 290° C. through a spinneret having an effective diameter of 88 mm;

[0118] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 14 mm, the width of the vertical segment is 11 mm, and the length is 48.5 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.54 mm, and the width is 0.09 mm. The length of the "cross" cross-section leaf of the spinneret is 0.34 mm, and the width is 0.09 mm. The number of spinnerets is 288.

[0119] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 5 cm, and then is cooled (i.e., a filament bundle is obtained);

[0120] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process divides the static pressure chamber into three parts. Each part of the static pressure chamber is controlled by an independent air valve to control the inlet pressure and air volume.

[0121] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.55m / s and the cooling length is 20cm; in the second stage, the wind speed is 0.6m / s and the cooling length is 50cm; in the third stage, the wind speed is 0.85m / s and the cooling length is 80cm; the cooling air temperature in each stage is the same, 22.6℃; the cooling humidity in each stage is the same, 70%;

[0122] (4) The product of step (3) was oiled at an oil concentration of 12%, and finally wound through a guide wire reel of a winding device at 3200 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0123] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 965 dtex, a breaking strength of 2.1 cN / dtex, a breaking strength CV value of 3.26%, a breaking elongation of 127%, a breaking elongation CV value of 1.28%, a yarn unevenness CV value of 1.47%, a morphology of 54.9%, a 36-position 24-hour hair degradation number of 1, and a 36-position 24-hour broken end number of 1.

[0124] Example 6

[0125] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0126] (1) Preparation of polyester melt;

[0127] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.24:1; the mass of the pentaerythritol suspension is 0.005% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0128] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 265° C. and a pressure of 95 kPa, and to a second esterification reaction at a temperature of 271° C. and a pressure of 35 kPa to produce bis(hydroxyethyl) terephthalate;

[0129] (1.3) A pre-polycondensation reaction of bis(hydroxyethyl) terephthalate was conducted at a temperature of 278.5°C in the pre-polycondensation upper chamber and 279.8°C in the lower chamber, and a pressure of 12.5 kPa in the upper chamber and 2.04 kPa in the lower chamber; a final polycondensation reaction was conducted at a temperature of 283.6°C and a pressure of 219 Pa to produce a polyester melt;

[0130] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 290.3° C. through a spinneret having an effective diameter of 87 mm;

[0131] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 14 mm, the width of the vertical segment is 12 mm, and the length is 48.5 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.55 mm, and the width is 0.1 mm. The length of the "cross" cross-section leaf of the spinneret is 0.35 mm, and the width is 0.1 mm. The number of spinnerets is 288.

[0132] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 6 cm, and then is cooled (i.e., a tow is obtained);

[0133] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is designed by designing three small static pressure chambers. Each small static pressure chamber has an independent air valve to control the inlet pressure and air volume;

[0134] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.6 m / s and the cooling length is 30 cm; in the second stage, the wind speed is 0.6 m / s and the cooling length is 50 cm; in the third stage, the wind speed is 0.9 m / s and the cooling length is 90 cm; the cooling air temperature in each stage is the same, which is 22.8°C; the cooling humidity in each stage is the same, which is 70.5%;

[0135] (4) The product of step (3) was oiled at an oil concentration of 12.3%, and finally wound through a guide wire reel of a winding device at 3250 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0136] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 965 dtex, a breaking strength of 2.26 cN / dtex, a breaking strength CV value of 1.75%, a breaking elongation of 127.3%, a breaking elongation CV value of 2.09%, a yarn unevenness CV value of 1.44%, a deformity of 49.5%, a 36-position 24-hour hair degradation number of 1, and a 36-position 24-hour broken end number of 3.

[0137] Example 7

[0138] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0139] (1) Preparation of polyester melt;

[0140] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.24:1; the mass of the pentaerythritol suspension is 0.006% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0141] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 266° C. and a pressure of 98 kPa, and to a second esterification reaction at a temperature of 272° C. and a pressure of 36 kPa to produce bis(hydroxyethyl) terephthalate;

[0142] (1.3) A pre-polycondensation reaction of bis(hydroxyethyl) terephthalate was conducted at a temperature of 279°C in the upper polycondensation chamber and 281.1°C in the lower chamber, and a pressure of 13 kPa in the upper chamber and 2.08 kPa in the lower chamber; a final polycondensation reaction was conducted at a temperature of 284°C and a pressure of 220 Pa to produce a polyester melt;

[0143] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 290.6° C. through a spinneret having an effective diameter of 86 mm;

[0144] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 14 mm, the width of the vertical segment is 10 mm, and the length is 48.5 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.56 mm, and the width is 0.11 mm. The length of the "cross" cross-section leaf of the spinneret is 0.36 mm, and the width is 0.11 mm. The number of spinnerets is 288.

[0145] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 7 cm, and then is cooled (i.e., a filament bundle is obtained);

[0146] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is designed by designing three small static pressure chambers. Each small static pressure chamber has an independent air valve to control the inlet pressure and air volume;

[0147] The specific process parameters for the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.6 m / s and the cooling length is 35 cm; in the second stage, the wind speed is 0.65 m / s and the cooling length is 42 cm; in the third stage, the wind speed is 0.85 m / s and the cooling length is 110 cm; the cooling air temperature in each stage is the same, 23°C; and the cooling humidity in each stage is the same, 71%.

[0148] (4) The product of step (3) was oiled at an oil concentration of 12.3%, and finally wound through a guide wire reel of a winding device at 3300 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0149] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.18 cN / dtex, a breaking strength CV value of 2.79%, an elongation at break of 128.1%, a breaking elongation CV value of 1.05%, a yarn unevenness CV value of 1.53%, a deformity of 60.3%, a 36-position 24-hour hair degradation number of 1, and a 36-position 24-hour broken end number of 1.

[0150] Example 8

[0151] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0152] (1) Preparation of polyester melt;

[0153] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.3:1; the mass of the pentaerythritol suspension is 0.006% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0154] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 267° C. and a pressure of 100 kPa, and to a second esterification reaction at a temperature of 273° C. and a pressure of 37 kPa to produce bis(hydroxyethyl) terephthalate;

[0155] (1.3) Pre-polycondensation of bis(hydroxyethyl) terephthalate was carried out at a temperature of 279.5°C in the upper polycondensation chamber and 281.4°C in the lower chamber, and at a pressure of 13.5 kPa in the upper chamber and 2.14 kPa in the lower chamber; and final polycondensation was carried out at a temperature of 284.3°C and a pressure of 222 Pa to produce a polyester melt;

[0156] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 291° C. through a spinneret having an effective diameter of 85 mm;

[0157] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 14 mm, the width of the vertical segment is 10 mm, and the length is 48.5 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.57 mm, and the width is 0.12 mm. The length of the "cross" cross-section leaf of the spinneret is 0.37 mm, and the width is 0.12 mm. The number of spinnerets is 288.

[0158] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 8 cm, and then is cooled (i.e., a filament bundle is obtained);

[0159] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process divides the static pressure chamber into three parts. Each part of the static pressure chamber is controlled by an independent air valve to control the inlet pressure and air volume.

[0160] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.6 m / s and the cooling length is 40 cm; in the second stage, the wind speed is 0.65 m / s and the cooling length is 45 cm; in the third stage, the wind speed is 0.8 m / s and the cooling length is 120 cm; the cooling air temperature in each stage is the same, at 23.2°C; and the cooling humidity in each stage is the same, at 71.5%.

[0161] (4) The product of step (3) was oiled at an oil concentration of 12.5%, and finally wound through a guide wire reel of a winding device at 3350 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0162] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.09 cN / dtex, a breaking strength CV value of 2.53%, a breaking elongation of 127.2%, a breaking elongation CV value of 2.47%, a yarn unevenness CV value of 1.49%, a deformity of 48.5%, a 36-position 24-hour hair degradation number of 3, and a 36-position 24-hour broken end number of 0.

[0163] Example 9

[0164] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0165] (1) Preparation of polyester melt;

[0166] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.24:1; the mass of the pentaerythritol suspension is 0.004% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0167] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 268° C. and a pressure of 103 kPa, and to a second esterification reaction at a temperature of 273.5° C. and a pressure of 38 kPa to produce bis(hydroxyethyl) terephthalate;

[0168] (1.3) Pre-polycondensation of bis(hydroxyethyl) terephthalate was carried out at a temperature of 280°C in the upper polycondensation chamber and 281.7°C in the lower chamber, and at a pressure of 14 kPa in the upper chamber and 2.18 kPa in the lower chamber; and final polycondensation was carried out at a temperature of 284.7°C and a pressure of 224 Pa to produce a polyester melt;

[0169] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 291.3° C. through a spinneret having an effective diameter of 82 mm;

[0170] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 12 mm, the width of the vertical segment is 12 mm, and the length is 49 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.58 mm, and the width is 0.13 mm. The length of the "cross" cross-section leaf of the spinneret is 0.38 mm, and the width is 0.13 mm. The number of spinnerets is 192.

[0171] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 9 cm, and then is cooled (i.e., a filament bundle is obtained);

[0172] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is designed by designing three small static pressure chambers. Each small static pressure chamber has an independent air valve to control the inlet pressure and air volume;

[0173] The specific process parameters for the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.6 m / s and the cooling length is 40 cm; in the second stage, the wind speed is 0.75 m / s and the cooling length is 48 cm; in the third stage, the wind speed is 0.9 m / s and the cooling length is 120 cm; the cooling air temperature in each stage is the same, at 23.4°C; and the cooling humidity in each stage is the same, at 72%.

[0174] (4) The product of step (3) was oiled at an oil concentration of 12%, and finally wound through a guide wire reel of a winding device at 3400 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0175] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 530 dtex, a breaking strength of 2.14 cN / dtex, a breaking strength CV value of 2.91%, an elongation at break of 128.2%, a breaking elongation CV value of 1.64%, a yarn unevenness CV value of 1.52%, a deformity of 51.2%, a 36-position 24-hour hair degradation number of 4, and a 36-position 24-hour broken end number of 0.

[0176] Example 10

[0177] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0178] (1) Preparation of polyester melt;

[0179] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.3:1; the mass of the pentaerythritol suspension is 0.005% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0180] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 269° C. and a pressure of 105 kPa, and to a second esterification reaction at a temperature of 274° C. and a pressure of 39 kPa to produce bis(hydroxyethyl) terephthalate;

[0181] (1.3) Pre-polycondensation of bis(hydroxyethyl) terephthalate was carried out at a temperature of 278°C in the upper polycondensation chamber and 282°C in the lower chamber, and at a pressure of 14.5 kPa in the upper chamber and 2.2 kPa in the lower chamber; and final polycondensation was carried out at a temperature of 285°C and a pressure of 225 Pa to produce a polyester melt;

[0182] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 291.5° C. through a spinneret having an effective diameter of 90 mm;

[0183] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 15 mm, the width of the vertical segment is 11 mm, and the length is 48.25 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.59 mm, and the width is 0.14 mm. The length of the "cross" cross-section leaf of the spinneret is 0.39 mm, and the width is 0.14 mm. The number of spinnerets is 288.

[0184] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 10 cm, and then is cooled (i.e., a filament bundle is obtained);

[0185] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is designed by designing three small static pressure chambers. Each small static pressure chamber has an independent air valve to control the inlet pressure and air volume;

[0186] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.58m / s and the cooling length is 25cm; in the second stage, the wind speed is 0.73m / s and the cooling length is 45cm; in the third stage, the wind speed is 0.88m / s and the cooling length is 100cm; the cooling air temperature in each stage is the same, 23.5℃; the cooling humidity in each stage is the same, 70%;

[0187] (4) The product of step (3) was oiled at an oil concentration of 12%, and finally wound through a guide wire reel of a winding device at 3450 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0188] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 580 dtex, a breaking strength of 2.21 cN / dtex, a breaking strength CV value of 3.27%, a breaking elongation of 127.8%, a breaking elongation CV value of 1.92%, a yarn unevenness CV value of 1.53%, a deformity of 64.2%, a 36-position 24-hour hair degradation number of 1, and a 36-position 24-hour broken end number of 4.

[0189] Comparative Example 2

[0190] A method for preparing a moisture-wicking polyester fiber is substantially the same as that of Example 10, except that step (3) does not employ a three-stage side-blowing cooling process, the cooling wind speed is 0.90 m / s, and the cooling length is the sum of the three-stage cooling lengths of Example 10;

[0191] The prepared moisture-wicking polyester fiber has a fineness of 580 dtex, a breaking strength of 2.11 cN / dtex, a breaking strength CV value of 6.82%, a breaking elongation of 124.5%, a breaking elongation CV value of 11.62%, a yarn unevenness CV value of 2.12%, a profile of 41.9%, a 24-hour hair degradation number of 27 at 36 positions, and a 24-hour end breakage number of 35 at 36 positions.

[0192] Comparing Comparative Example 2 with Example 10, it can be found that the CV values ​​of breaking strength, elongation at break, unevenness of strands, 36-digit 24-hour fluff grade degradation, and 36-digit 24-hour end-breakage in Comparative Example 2 are significantly higher than those in Example 10. This is because the wind speed, which is uniform at 0.90 m / s, is relatively high, causing the fibers to rotate and tremble violently. This results in abnormal nozzle stretching after the melt is extruded from the spinneret, resulting in an increase in end-breakage and fluff. This also increases the CV values ​​of breaking strength, elongation at break, and unevenness of strands.

[0193] Example 11

[0194] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0195] (1) Preparation of polyester melt;

[0196] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.26:1; the mass of the pentaerythritol suspension is 0.008% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0197] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 270° C. and a pressure of 107 kPa, and to a second esterification reaction at a temperature of 274.5° C. and a pressure of 40 kPa to produce bis(hydroxyethyl) terephthalate;

[0198] (1.3) Pre-polycondensation of bis(hydroxyethyl) terephthalate was carried out at a temperature of 278.3°C in the upper polycondensation chamber and 280°C in the lower chamber, and at a pressure of 15 kPa in the upper chamber and 2.15 kPa in the lower chamber; and final polycondensation was carried out at a temperature of 283.5°C and a pressure of 228 Pa to produce a polyester melt;

[0199] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 291.7° C. through a spinneret having an effective diameter of 84 mm;

[0200] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 15 mm, the width of the vertical segment is 12 mm, and the length is 48.25 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.6 mm, and the width is 0.15 mm. The length of the "cross" cross-section leaf of the spinneret is 0.4 mm, and the width is 0.15 mm. The number of spinnerets is 192.

[0201] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 8 cm, and then is cooled (i.e., a filament bundle is obtained);

[0202] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process is designed by designing three small static pressure chambers. Each small static pressure chamber has an independent air valve to control the inlet pressure and air volume;

[0203] The specific process parameters for the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.54 m / s and the cooling length is 27 cm; in the second stage, the wind speed is 0.7 m / s and the cooling length is 50 cm; in the third stage, the wind speed is 0.9 m / s and the cooling length is 110 cm; the cooling air temperature in each stage is the same, at 23.1°C; and the cooling humidity in each stage is the same, at 70.5%.

[0204] (4) The product of step (3) was oiled at an oil concentration of 12%, and finally wound through a guide wire reel of a winding device at 3500 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0205] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.2 cN / dtex, a breaking strength CV value of 3.22%, a breaking elongation of 128.1%, a breaking elongation CV value of 0.69%, a yarn unevenness CV value of 1.57%, a deformity of 59.4%, a 36-position 24-hour hair degradation number of 3, and a 36-position 24-hour broken end number of 1.

[0206] Example 12

[0207] A method for preparing moisture-absorbing and perspiration-wicking polyester fiber, comprising the following steps:

[0208] (1) Preparation of polyester melt;

[0209] (1.1) A suspension of purified terephthalic acid, ethylene glycol, and pentaerythritol is stirred in a stirrer to form a uniform slurry suspension; wherein the molar ratio of ethylene glycol to purified terephthalic acid is 1.29:1; the mass of the pentaerythritol suspension is 0.006% of the total mass of the purified terephthalic acid and ethylene glycol; the pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:98;

[0210] (1.2) subjecting the slurry suspension to a first esterification reaction at a temperature of 268° C. and a pressure of 110 kPa, and to a second esterification reaction at a temperature of 275° C. and a pressure of 35 kPa to produce bis(hydroxyethyl) terephthalate;

[0211] (1.3) A pre-polycondensation reaction of bis(hydroxyethyl) terephthalate was conducted at a temperature of 277.8°C in the upper polycondensation chamber and 280.3°C in the lower chamber, and a pressure of 14 kPa in the upper chamber and 2.14 kPa in the lower chamber; a final polycondensation reaction was conducted at a temperature of 283.4°C and a pressure of 230 Pa to produce a polyester melt;

[0212] (2) the polyester melt obtained in step (1) was first metered and then melt-extruded at 292° C. through a spinneret having an effective diameter of 84 mm;

[0213] The spinneret consists of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The diameter of the circular area is 14 mm, the width of the vertical segment is 11 mm, and the length is 48.5 mm. The spinnerets on the spinneret are "cross" cross-section spinnerets. The length of the "cross" cross-section leaf of the spinneret is 0.58 mm, and the width is 0.1 mm. The length of the "cross" cross-section leaf of the spinneret is 0.35 mm, and the width is 0.1 mm. The number of spinnerets is 192.

[0214] (3) The product melt-extruded from the spinneret in step (2) first passes through a windless zone with a length of 6 cm, and then is cooled (i.e., a tow is obtained);

[0215] The cooling adopts a three-stage side-blowing cooling process. The three-stage side-blowing cooling process divides the static pressure chamber into three parts. Each part of the static pressure chamber is controlled by an independent air valve to control the inlet pressure and air volume.

[0216] The specific process parameters of the three-stage side-blowing cooling are as follows: in the first stage, the wind speed is 0.6m / s and the cooling length is 30cm; in the second stage, the wind speed is 0.72m / s and the cooling length is 50cm; in the third stage, the wind speed is 0.88m / s and the cooling length is 70cm; the cooling air temperature in each stage is the same, which is 23.2℃; the cooling humidity in each stage is the same, which is 70.5%;

[0217] (4) The product of step (3) was oiled at an oil concentration of 12%, and finally wound through a guide wire reel of a winding device at 3300 m / min to obtain a moisture-absorbing and perspiration-releasing polyester fiber.

[0218] The final moisture-absorbing and perspiration-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.21 cN / dtex, a breaking strength CV value of 1.46%, an elongation at break of 129.9%, a breaking elongation CV value of 0.71%, a yarn unevenness CV value of 1.49%, a deformity of 47.2%, a 36-position 24-hour hair degradation number of 4, and a 36-position 24-hour broken end number of 3.

[0219] Comparative Example 3

[0220] A method for preparing moisture-absorbing and perspiration-releasing polyester fiber is basically the same as that in Example 12, except that step (2) does not use a spinneret with a "yuanbao"-shaped area of ​​the air duct without spinneret holes, but instead uses a multi-circle circular arrangement.

[0221] The prepared moisture-wicking polyester fiber has a fineness of 758 dtex, a breaking strength of 2.03 cN / dtex, a breaking strength CV value of 6.79%, a breaking elongation of 128.3%, a breaking elongation CV value of 8.61%, a yarn unevenness CV value of 2.04%, a profile of 41.2%, a 36-bit 24-hour hair degradation number of 16, and a 36-bit 24-hour end breakage number of 24.

[0222] Comparing Comparative Example 3 with Example 12, it can be seen that the CV values ​​of breaking strength, elongation at break, yarn unevenness, 36-position 24-hour fluff degradation, and 36-position 24-hour end-breakage in Comparative Example 3 are significantly higher than those in Example 12. This is because the spinneret holes are arranged in a multi-circular pattern, resulting in different cooling effects between the inner and outer layers of the yarn bundles, leading to increased CV values ​​of breaking strength, elongation at break, and yarn unevenness. Furthermore, the outer coils have poor cooling effects, which can easily cause the yarn bundles to shake and collide, resulting in fluff and loose yarns.

Claims

1. A method for preparing a moisture wicking polyester fiber, wherein the polyester melt is metered, melt-extruded from a spinneret, cooled, oiled, and wound to obtain the moisture wicking polyester fiber, wherein the spinneret holes on the spinneret are "cross" cross-section spinneret holes, and the method is characterized in that: The cooling adopts a three-stage side-blowing cooling process. The three-stage process from top to bottom is as follows: In the first stage, the wind speed is 0.45-0.60 m / s and the cooling length is 10-40 cm; In the second stage, the wind speed is 0.60-0.75 m / s and the cooling length is 40-50 cm; The third stage, wind speed is 0.75-0.90m / s, cooling length is 50-120cm; The number of spinneret holes is 192 to 288 holes; The spinneret is composed of a spinneret hole area and a spinneret-free area. All spinnerets are evenly distributed in a ring shape in the spinneret hole area. The spinneret-free area includes a U-shaped area and a circular area located inside the U-shaped area. The center of the circular area coincides with the center of the spinneret. The U-shaped area is composed of an arc segment and two vertical segments connected at both ends of the arc segment. The two vertical segments extend to the edge of the spinneret. The circular area fits the inner wall of the arc segment. The width of the vertical segment is the difference between the radii of the circles where the two adjacent circles of spinnerets are located. The two vertical segments of the U-shaped area are perpendicular to the cooling air mesh plate.

2. The method for preparing a moisture wicking polyester fiber according to claim 1, characterized in that: The cooling air temperature of each section is equal, which is 22-23.5°C; the cooling humidity of each section is equal, which is 68-72%.

3. The method for preparing a moisture wicking polyester fiber according to claim 1, characterized in that: The three-stage side-blowing cooling process is achieved by dividing the static pressure chamber into three parts or designing three small static pressure chambers. Each part of the static pressure chamber or each small static pressure chamber is controlled by an independent air valve to control the inlet pressure and air volume.

4. The method for preparing a moisture wicking polyester fiber according to claim 1, characterized in that: After the polyester melt is extruded through the spinneret, it passes through a windless zone before being cooled. The length of the windless zone does not exceed 10 cm.

5. The method for preparing a moisture wicking polyester fiber according to claim 1, characterized in that: The effective diameter of the spinneret is 80-90 mm; the length of the "cross" section leaf of the spinneret hole is 0.5-0.6 mm, and the width is 0.05-0.15 mm; the length of the "cross" section leaf of the spinneret hole is 0.3-0.4 mm, and the width is 0.05-0.15 mm.

6. The method for preparing a moisture wicking polyester fiber according to claim 1, characterized in that: Purified terephthalic acid, ethylene glycol and pentaerythritol suspension are stirred by a stirrer to form a uniform slurry suspension, and the polyester melt is obtained by esterification and polycondensation of the slurry suspension; The molar ratio of ethylene glycol to purified terephthalic acid is 1.1 to 1.3:1; The mass of the pentaerythritol suspension is 0.002-0.008% of the total mass of the purified terephthalic acid and ethylene glycol; The pentaerythritol suspension is prepared by mixing pentaerythritol and ethylene glycol in a mass ratio of 2:

98.

7. The method for preparing a moisture wicking polyester fiber according to claim 1, characterized in that: The melt extrusion temperature is 288-292° C., the oil concentration is 11.5-12.5%, and the winding speed is 3000-3500 m / min.

8. The moisture wicking polyester fiber prepared by the method according to any one of claims 1 to 7, characterized in that: The fineness of the moisture wicking polyester fiber is 500-965 dtex, the breaking strength is ≥2.0 cN / dtex, the breaking strength CV value is ≤4.0%, the breaking elongation is 128±3.0%, the breaking elongation CV value is ≤4.0%, the yarn unevenness CV value is ≤1.80%, and the degree of irregularity is ≥44%.

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