Preparation method of fine denier modal and dty filament high count composite yarn

Abstract

The application discloses a preparation method of fine denier modal and DTY filament high-count composite yarn, and technical solution points are as follows: including the following steps: S1, carding combination: adopting 1.0 dtex*39 mm fine denier modal fiber as raw material, setting the cotton opener needle beater speed to be 400r / min-440r / min, the cotton carding machine cylinder speed to be 340r / min-360r / min, the flat speed to be 78m / min-83m / min, the taker-in speed to be 820r / min-850r / min, the doffer speed to be 50r / min-54r / min, setting the cylinder-flat four-point gauge to be 8*7*7*8, and the sliver weight to be 18g / 5m; S2, drawing; S3, roving: in the roving process, the parameters are set as follows: the weight is 3.5g / 10m, the flyer speed is 600-800r / min, the roller gauge is 10*23*35mm, the back zone draft ratio is 1.23, and the total draft is 8.1-8.5 times; and S4, spinning. The application has process innovation, produces fine denier modal roving with light weight by adjusting the front spinning process, and makes the quality stable.

Description

Technical Field

[0001] This invention relates to the field of textile technology, and in particular to a method for preparing a high-count composite yarn of fine denier modal and DTY filament. Background Technology

[0002] Modal fiber is a cellulose fiber, a pure man-made fiber. It is made from wood pulp through a specialized spinning process. The raw material comes from natural wood, is biodegradable, and is an environmentally friendly recycled fiber. The fiber is soft, smooth, and brightly colored, resulting in fabrics with an exceptionally soft hand feel and a lustrous sheen. It is a natural mercerized fabric. Modal fiber also has strong moisture absorption, keeping fabrics dry and breathable, making it ideal for intimate apparel and health-related clothing. However, Modal fabrics have relatively poor drape.

[0003] DTY, or Draw Texturing Yarn, is a type of textured polyester fiber. It is made from polyester chips (PET) as raw material, spun at high speed into pre-oriented polyester yarn (POY), and then processed through drawing and false twisting. In addition to the general characteristics of polyester, such as high breaking strength and modulus of elasticity, excellent heat setting, good resilience, heat resistance, light resistance, strong corrosion resistance, insulation, crispness, easy washing, and quick drying, it also features high bulkiness, good thermal insulation, comfortable hand feel, and soft luster.

[0004] A Chinese patent with publication number CN100540771C discloses a blended yarn made of fine denier modal fiber, either spun purely or blended with other fibers, and its production method. The fine denier modal fiber blended yarn of this invention is characterized by being made from two or more fibers of different colors through blending and spinning, wherein the fine denier modal fiber content in the blended yarn is 40% to 100%.

[0005] The aforementioned patents and current technologies lack materials that combine the properties of modal fibers and polyester low-elasticity yarns, which is also a major gap in the current market. Summary of the Invention

[0006] In view of the problems mentioned in the background art, the purpose of this invention is to provide a method for preparing high-count composite yarn of fine denier modal and DTY filaments, so as to solve the problems mentioned in the background art.

[0007] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0008] A method for preparing a high-count composite yarn of fine denier modal and DTY filaments includes the following steps:

[0009] S1. Carding and cleaning unit: Using 1.0dtex*39mm fine denier modal fiber as raw material, the opening machine carding needle beater speed is set to 400r / min-440r / min, the carding machine cylinder speed is set to 340r / min-360r / min, the flats speed is set to 78m / min-83m / min, the licker-in speed is set to 820r / min-850r / min, and the doffer speed is set to 48r / min-52r / min. The cylinder-flats four-point spacing is set to 8*7*7*8, and the sliver weight is set to 18g / 5m.

[0010] S2, Drawing: This includes the first drawing process and the second drawing process. In the first drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 5.5-6.5 times, and the rear draft ratio is 1.75. In the second drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 7-8 times, and the rear draft ratio is 1.35. Both drawing processes are carried out at low speeds, not exceeding 240m / min.

[0011] S3, Roving: In the roving process, the parameters are set as follows: basis weight 3.5g / 10m, spindle speed 750-850r / min, roller spacing 10×23×35mm, back zone draft ratio 1.23, and total draft 8.1-8.5 times.

[0012] S4. Spinning: The spinning process uses modified proprietary filament spinning equipment and composite filament-staple fiber spinning technology. Modal fiber is used as the outer core sheath fiber, which is output from the drafting device through the front roller. Polyester low-elasticity yarn is used as the core yarn, which is fed directly from the front roller through a proprietary filament tension device and a yarn guide device. The filament is in the middle of the sliver, and the core is spun to form a core sheath type yarn structure. 865 coated rollers are selected, and the temperature and humidity of the spinning process are controlled. The main process parameters for spinning are set as follows: design twist coefficient 440; back zone understretch ratio 1.21; roller spacing 19*45mm.

[0013] S5. Winding: The winding process adopts the air twisting joint process, optimizes the electric clearing curve to remove harmful yarn defects; adjusts the tension to ensure the tension and formation of the yarn package, and checks and eliminates the internal breakage and web head phenomenon of the yarn package;

[0014] S6. Primary performance treatment: Prepare a performance treatment agent by using 3g / L caustic soda, 1g / L organic complexing agent and 1g / L penetrant NFD. Then, put the yarn into the performance treatment agent and treat it at 50℃ for 50min. After that, heat the performance treatment agent to 100℃ at a rate of 3℃ / min and keep it at that temperature for 30min. Then, rinse it repeatedly with clean water at 40℃.

[0015] S7. Secondary performance treatment: Perform softening treatment by using a 0.5% to 1% soap or synthetic detergent solution by weight of the fabric, and adding 8‰ soda ash by weight of the fabric. Treat at 80 to 90°C for 30 to 50 minutes, then wash with cold water at 1°C and air dry.

[0016] Preferably, in step S1, 1.0 dtex*39 mm fine denier modal fiber is used as raw material, and the carding speed of the opening machine is set to 420 r / min, the carding cylinder speed is set to 360 r / min, the flats speed is set to 81 m / min, the licker-in speed is set to 840 r / min, the doffer speed is set to 52 r / min, the four-point spacing between the cylinder and the flats is set to 8*7*7*8, and the sliver weight is set to 18 g / 5 m.

[0017] Preferably, S2 includes a first drawing process and a second drawing process. In the first drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 6.0 times, and the rear draft ratio is 1.75. In the second drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 7.5 times, and the rear draft ratio is 1.35. The two drawing processes are carried out at a low speed, not exceeding 240m / min.

[0018] Preferably, in S3, during the roving process, the parameters are set as follows: basis weight 3.5g / 10m, spindle speed 650-750r / min, roller spacing 10×23×35mm, back zone draft ratio 1.23, and total draft ratio 8.3.

[0019] Preferably, in step S4, an 865 coated roller with medium-hard elasticity is selected, and the temperature and humidity of the yarn are controlled. The main process parameters of the yarn are set as follows: design twist coefficient 440; back zone understretch ratio 1.21; roller spacing 19*45mm.

[0020] Preferably, in step S4, when controlling the temperature and humidity of the yarn, the yarn temperature is controlled to be 29℃-33℃.

[0021] Preferably, the yarn after winding in S5 is tested, and the test items include yarn linear density, coefficient of variation of weight per 100 meters, yarn twist, single yarn breaking strength, and coefficient of variation of single yarn breaking strength.

[0022] In summary, the present invention has the following main beneficial effects:

[0023] This invention features a technological innovation: by adjusting the pre-spinning process, it produces lightweight, fine-denier modal roving with stable quality. The spinning process utilizes modified proprietary filament spinning equipment and a composite filament-staple fiber spinning technology. Modal fiber, acting as the outer core sheath fiber, is output from the drafting device via the front roller. Polyester low-elasticity yarn is used as the core yarn, fed directly into the front roller via a proprietary filament tension device and guide device. The filament is spun in the middle of the sliver, forming a core-sheath type yarn structure. Improved spinning equipment employs special cotton-type undercoat and pressure bar spacers to enhance fiber control, reduce neps, and ensure overall yarn quality. Attached Figure Description

[0024] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] refer to Figure 1 A method for preparing a high-count composite yarn of fine denier modal and DTY filaments includes the following steps:

[0028] S1. Cleaning and combing process:

[0029] Using 1.0dtex*39mm fine denier modal fiber as raw material, the opening machine carding needle beater speed is set to 400r / min, the carding machine cylinder speed is set to 340r / min, the flats speed is set to 78m / min, the licker-in speed is set to 820r / min, the doffer speed is set to 48r / min, the cylinder-flats four-point spacing is set to 8*7*7*8, and the sliver weight is set to 18g / 5m.

[0030] S2, Drawing process:

[0031] The process employs a two-stage sliver ...

[0032] S3, Roving process:

[0033] S3, Roving: In the roving process, the parameters are set as follows: basis weight 3.5g / 10m, spindle speed 750r / min, roller spacing 10×23×35mm, back zone draft ratio 1.23, and total draft 8.1 times.

[0034] S4. Spinning process:

[0035] The spinning process uses modified proprietary filament spinning equipment and filament-staple fiber composite spinning technology. Modal fiber is used as the outer core sheath fiber and is output from the drafting device through the front roller. Polyester low elasticity yarn is used as the core yarn and is fed directly from the front roller through a proprietary filament tension device and yarn guide device. The filament is in the middle of the sliver and is spun into a core sheath type yarn structure.

[0036] The equipment uses 865 coated rollers and controls the temperature and humidity of the yarn. To reduce hairiness, a lower spindle speed is used and the weight of the traveler is increased to stabilize the air ring. At the same time, special cotton-type underpinning and pressure bar spacers are used to strengthen fiber control, reduce free fibers, reduce neps, and ensure the overall quality level of the yarn.

[0037] Main process parameters for fine spinning: design twist coefficient 440; back zone understretch ratio 1.21; roller spacing 19*45mm.

[0038] S5. Winding process:

[0039] The winding process employs an air-twisting joint technology to ensure joint strength and appearance. Simultaneously, the electro-cleaning curve is optimized to eliminate harmful yarn defects; appropriate tension is selected to ensure yarn tension and shaping, preventing internal yarn breakage and web-like defects.

[0040] S6. Primary performance treatment: Prepare a performance treatment agent by using 3g / L caustic soda, 1g / L organic complexing agent and 1g / L penetrant NFD. Then, put the yarn into the performance treatment agent and treat it at 50℃ for 50min. After that, heat the performance treatment agent to 100℃ at a rate of 3℃ / min and keep it at that temperature for 30min. Then, rinse it repeatedly with clean water at 40℃.

[0041] S7. Secondary Performance Treatment: A softening treatment is performed using a 0.5%–1% soap or synthetic detergent solution by weight of the fabric, along with 8‰ soda ash by weight of the fabric. The mixture is treated at 80–90°C for 30–50 minutes, then rinsed with cold water at 1°C and air-dried. By utilizing the above chemical and physical methods, various impurities can be removed, resulting in improved hygroscopicity and whiteness of the yarn, as well as better breaking strength and elongation at break. Furthermore, the process is easy to control.

[0042] The yarn after passing through the S5 winding is tested, and the test items include yarn linear density, coefficient of variation of weight per 100 meters, yarn twist, single yarn breaking strength, and coefficient of variation of single yarn breaking strength.

[0043] The innovative process of this invention involves adjusting the pre-spinning process to produce lightweight, fine-denier modal roving with stable quality. The spinning process utilizes modified proprietary filament spinning equipment and a composite filament-staple fiber spinning technology. Modal fiber, acting as the outer core sheath fiber, is output from the drafting device via the front roller. Polyester low-elasticity yarn is used as the core yarn, fed directly into the front roller via a proprietary filament tension device and guide device. The filament is spun in the middle of the sliver, forming a core-sheath type yarn structure. Improved spinning equipment employs special cotton-type undercoat and pressure bar spacers to enhance fiber control, reduce neps, and ensure overall yarn quality.

[0044] Example 2

[0045] refer to Figure 1 A method for preparing a high-count composite yarn of fine denier modal and DTY filaments includes the following steps:

[0046] S1. Cleaning and combing process:

[0047] Using 1.0dtex*39mm fine denier modal fiber as raw material, the opening machine carding speed is set to 440r / min, the carding machine cylinder speed to 360r / min, the flats speed to 83m / min, the licker-in speed to 850r / min, and the doffer speed to 52r / min. The cylinder-flats four-point spacing is set to 8*7*7*8, and the sliver weight is 18g / 5m.

[0048] S2, Drawing process:

[0049] The two-stage drawing process includes a first drawing stage and a second drawing stage. After the first drawing stage, the draft ratio should be kept relatively high, while the total draft ratio should be kept relatively low; after the second drawing stage, the draft ratio should be kept relatively low, while the total draft ratio should be kept relatively high. This improves weight unevenness, increases fiber straightness, and strengthens control over fiber rebound. In the first drawing stage, 6 fibers are drawn together, with a roller spacing of 16×9×20mm, a total draft ratio of 6.0, and a back zone draft ratio of 1.8. In the second drawing stage, 6 fibers are drawn together, with a roller spacing of 16×9×20mm, a total draft ratio of 8, and a back zone draft ratio of 1.4. Both drawing stages are performed at low speeds, not exceeding 240m / min.

[0050] S3, Roving process:

[0051] S3, Roving: In the roving process, the parameters are set as follows: basis weight 3.5g / 10m, spindle speed 850r / min, roller spacing 10×23×35mm, back zone draft ratio 1.23, and total draft 8.5 times.

[0052] S4. Spinning process:

[0053] The spinning process employs a composite spinning technology of long filament and short fiber. Modal fiber is used as the outer core sheath fiber and is output from the drafting device through the front roller. Polyester low elastic yarn is used as the core yarn and is directly fed into the front roller through the filament tension device and the yarn guide device. The filament is in the middle of the sliver, and the core is spun to form a core sheath type yarn structure.

[0054] The equipment uses 865 coated rollers and controls the temperature and humidity of the yarn. To reduce hairiness, a lower spindle speed is used and the weight of the traveler is increased to stabilize the air ring. At the same time, special cotton-type underpinning and pressure bar spacers are used to strengthen fiber control, reduce free fibers, reduce neps, and ensure the overall quality level of the yarn.

[0055] Main process parameters for fine spinning: design twist coefficient 440; back zone understretch ratio 1.21; roller spacing 19*45mm.

[0056] S5. Winding process:

[0057] The winding process employs an air-twisting joint technology to ensure joint strength and appearance. Simultaneously, the electro-cleaning curve is optimized to eliminate harmful yarn defects; appropriate tension is selected to ensure yarn tension and shaping, preventing internal yarn breakage and web-like defects.

[0058] S6. Primary performance treatment: Prepare a performance treatment agent by using 3g / L caustic soda, 1g / L organic complexing agent and 1g / L penetrant NFD. Then, put the yarn into the performance treatment agent and treat it at 50℃ for 50min. After that, heat the performance treatment agent to 100℃ at a rate of 3℃ / min and keep it at that temperature for 30min. Then, rinse it repeatedly with clean water at 40℃.

[0059] S7. Secondary Performance Treatment: A softening treatment is performed using a 0.5%–1% soap or synthetic detergent solution by weight of the fabric, along with 8‰ soda ash by weight of the fabric. The mixture is treated at 80–90°C for 30–50 minutes, then rinsed with cold water at 1°C and air-dried. By utilizing the above chemical and physical methods, various impurities can be removed, resulting in improved hygroscopicity and whiteness of the yarn, as well as better breaking strength and elongation at break. Furthermore, the process is easy to control.

[0060] The yarn after passing through the S5 winding is tested, and the test items include yarn linear density, coefficient of variation of weight per 100 meters, yarn twist, single yarn breaking strength, and coefficient of variation of single yarn breaking strength.

[0061] The innovative process of this invention involves adjusting the pre-spinning process to produce lighter-weight, finer-denier modal roving while maintaining stable quality. The spinning process employs a composite spinning technology of long filament and short fiber, using modal fiber as the outer core sheath fiber, which is output from the drafting device via the front roller; polyester low-elasticity yarn is used as the core yarn, fed directly from the front roller by the guide device, with the filament in the middle of the sliver, forming a core-sheath type yarn structure. Improved spinning equipment utilizes a special cotton-type undercoat and pressure bar spacer to enhance fiber control, reduce neps, and ensure the overall quality level of the yarn.

[0062] Example 3

[0063] refer to Figure 1 A method for preparing a high-count composite yarn of fine denier modal and DTY filaments includes the following steps:

[0064] S1. Cleaning and combing process:

[0065] Using 1.0dtex*39mm fine denier modal fiber as raw material, the opening machine carding speed is set to 420r / min, the carding machine cylinder speed is set to 350r / min, the flats speed is set to 79m / min, the licker-in speed is set to 840r / min, the doffer speed is set to 49r / min, the cylinder-flats four-point spacing is set to 8*7*7*8, and the sliver weight is set to 18g / 5m.

[0066] S2, Drawing process:

[0067] The two-stage drawing process includes a first drawing stage and a second drawing stage. After the first drawing stage, the draft ratio should be kept relatively high, while the total draft ratio should be kept relatively low; after the second drawing stage, the draft ratio should be kept relatively low, while the total draft ratio should be kept relatively high. This improves weight unevenness, increases fiber straightness, and strengthens control over fiber rebound. In the first drawing stage, 6 fibers are drawn together, with a roller spacing of 16×9×20mm, a total draft ratio of 6.0, and a back zone draft ratio of 1.75. In the second drawing stage, 6 fibers are drawn together, with a roller spacing of 16×9×20mm, a total draft ratio of 7.5, and a back zone draft ratio of 1.35. Both drawing stages are performed at low speeds, not exceeding 240m / min.

[0068] S3, Roving process:

[0069] The roving process employs a reasonable roller spacing to ensure smooth drafting of the sliver. The basis weight is 3.5g / 10m, the spindle speed is 650-750r / min, the roller spacing is 10×23×35mm, the back zone draft ratio is 1.23, and the total draft ratio is 8.3.

[0070] S4. Spinning process:

[0071] The spinning process employs an astronomical filament device and a composite spinning technology of filament and staple fiber. Modal fiber is used as the outer core sheath fiber and is output from the drafting device through the front roller. Polyester low-elasticity yarn is used as the core yarn and is directly fed into the front roller through the astronomical filament tension device and the yarn guide device. The filament is in the middle of the sliver and is spun into a core sheath type yarn structure.

[0072] The equipment uses 865 coated rubber rollers with medium stiffness and elasticity, and the temperature and humidity of the fine yarn are well controlled. To reduce hairiness, a lower spindle speed is used and the weight of the steel traveler is increased to stabilize the air ring. At the same time, special cotton-type underpinning and pressure bar spacers are used to strengthen fiber control, reduce free fibers, reduce neps, and ensure the overall quality level of the yarn.

[0073] Main process parameters for fine spinning: design twist coefficient 440; back zone understretch ratio 1.21; roller spacing 19*45mm.

[0074] S5. Winding process:

[0075] The winding process employs an air-twisting joint technology to ensure joint strength and appearance. Simultaneously, the electro-cleaning curve is optimized to eliminate harmful yarn defects; appropriate tension is selected to ensure yarn tension and shaping, preventing internal yarn breakage and web-like defects.

[0076] S6. Primary performance treatment: Prepare a performance treatment agent by using 3g / L caustic soda, 1g / L organic complexing agent and 1g / L penetrant NFD. Then, put the yarn into the performance treatment agent and treat it at 50℃ for 50min. After that, heat the performance treatment agent to 100℃ at a rate of 3℃ / min and keep it at that temperature for 30min. Then, rinse it repeatedly with clean water at 40℃.

[0077] S7. Secondary Performance Treatment: A softening treatment is performed using a 0.5%–1% soap or synthetic detergent solution by weight of the fabric, along with 8‰ soda ash by weight of the fabric. The mixture is treated at 80–90°C for 30–50 minutes, then rinsed with cold water at 1°C and air-dried. By utilizing the above chemical and physical methods, various impurities can be removed, resulting in improved hygroscopicity and whiteness of the yarn, as well as better breaking strength and elongation at break. Furthermore, the process is easy to control.

[0078] The yarn after passing through the S5 winding is tested, and the test items include yarn linear density, coefficient of variation of weight per 100 meters, yarn twist, single yarn breaking strength, and coefficient of variation of single yarn breaking strength.

[0079] The innovative process of this invention involves adjusting the pre-spinning process to produce lighter-weight, finer-denier modal rovings while maintaining stable quality. The spinning process utilizes an astronomical filament spinning device and a composite filament-staple fiber spinning technique. Modal fiber, acting as the outer core sheath fiber, is output from the drafting device via the front roller. Polyester low-elasticity yarn is used as the core yarn, fed directly from the front roller through an astronomical filament tension device and a guide device. The filament is spun in the middle of the sliver, forming a core-sheath yarn structure. Improved spinning equipment employs a special cotton-type undercoat and pressure bar spacers to enhance fiber control, reduce neps, and ensure overall yarn quality.

[0080] To verify the superiority of the present invention, the performance of the yarns in the prior art documents was compared with that of the yarns in Embodiments 1, 2, and 3, and the results were converted to percentages according to the prior art documents. The following results are shown in the table below:

[0081] Fiber strength Fiber approximation flatness hoop force elasticity Comparison documents 100％ 100％ 100％ 100％ 100％ Example 1 134％ 155％ 123％ 143％ 137％ Example 2 137％ 151％ 125％ 141％ 135％ Example 3 129％ 156％ 121％ 146％ 131％

[0082] The following conclusions can be drawn from the testing experiments:

[0083] Regardless of whether it is Example 1, Example 2 or Example 3, the quality of the yarn produced according to its production process is better than that of the comparative document, with significant improvements in properties such as fiber strength, fiber similarity, smoothness, hoops force and elasticity.

[0084] Furthermore, to investigate the quality difference between yarns using steps S6 and S7 and those not using steps S6 and S7 in this invention, taking Example 1 as an example, experiments were conducted with steps S6 only, steps S7 only, steps S6 and S7 simultaneously, and steps S6 and S7 simultaneously not used. The data were summarized, and the test results were percentaged with steps S6 and S7 not used as a control, resulting in the following table:

[0085]

[0086] The table above shows that the experimental results using only steps S6 and S7 are superior to those using neither steps S6 nor S7; and the experimental results using both steps S6 and S7 are superior to those using only steps S6 and S7.

[0087] In this experiment, the fiber strength was determined using ASTM D5035-2006(2008)e1, Textiles - Tensile properties of fabrics: strip method for determining breaking strength and elongation at break; and ASTM D5034-2009, Textiles - Tensile properties of fabrics: grip method for determining breaking strength and elongation at break. The results of the two experiments were averaged and then percentageified.

[0088] The direct indicator of fiber approximation is fiber thickness, generally expressed by fiber diameter and cross-sectional area, which is suitable for round fibers. This invention adopts this measurement method.

[0089] Fiber smoothness was tested according to AATCC124 standard, and the washing method was the same as the shrinkage test.

[0090] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-count composite yarn of fine denier modal and DTY filaments, characterized in that: Includes the following steps: S1. Carding and Cleaning Unit: Uses 1.0 dtex*39mm fine denier modal fiber as raw material. The carding speed is set at 400 r / min-440 r / min, the carding cylinder speed at 340 r / min-360 r / min, and the flats speed at 78 m / min. The speed is 83m / min, the licker-in speed is 820r / min-850r / min, the doffer speed is 48r / min-52r / min, the cylinder-cover plate four-point spacing is set to 8*7*7*8, and the raw sliver weight is 18g / 5m; S2, Drawing: This includes the first drawing process and the second drawing process. In the first drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 5.5-6.5 times, and the rear draft ratio is 1.

75. In the second drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 7-8 times, and the rear draft ratio is 1.

35. Both drawing processes are carried out at low speeds, not exceeding 240m / min. S3, Roving: In the roving process, the parameters are set as follows: basis weight 3.5g / 10m, spindle speed 750-850r / min, roller spacing... 10×23×35mm, rear zone draw ratio 1.23, total draw ratio 8.1-8.5; S4. Spinning: The spinning process utilizes modified proprietary filament spinning equipment and composite filament-staple fiber spinning technology. Modal fiber is used as the outer core-sheath fiber, output from the drafting device via the front roller. Polyester low-elasticity yarn is used as the core yarn, fed directly from the front roller via a proprietary filament tension device and guide device. The filament is spun in the middle of the sliver, forming a core-sheath type yarn structure. 865 coating rollers are used to control the temperature and humidity of the fine yarn. The main process parameters for fine yarn are set as follows: design twist coefficient 440; back zone understretch ratio 1.21; roller spacing 19*45mm. S5. Winding: The winding process adopts the air twisting joint process, optimizes the electric clearing curve to remove harmful yarn defects; adjusts the tension to ensure the tension and formation of the yarn package, and checks and eliminates the internal breakage and web head phenomenon of the yarn package; S6. Primary performance treatment: Prepare a performance treatment agent by using 3g / L caustic soda, 1g / L organic complexing agent and 1g / L penetrant NFD. Then, put the yarn into the performance treatment agent and treat it at 50℃ for 50min. After that, heat the performance treatment agent to 100℃ at a rate of 3℃ / min and keep it at that temperature for 30min. Then, rinse it repeatedly with clean water at 40℃. S7. Secondary performance treatment: Perform softening treatment by using a 0.5% to 1% soap or synthetic detergent solution by weight of the fabric, and adding 8‰ soda ash by weight of the fabric. Treat at 80 to 90°C for 30 to 50 minutes, then wash with cold water at 1°C and air dry. In S1, 1.0 dtex*39 mm fine denier modal fiber is used as raw material. The opening machine carding needle beater speed is set to 420 r / min, the carding machine cylinder speed is set to 360 r / min, the flat plate speed is set to 81 m / min, the licker-in speed is set to 840 r / min, the doffer speed is set to 52 r / min, the cylinder-flat plate four-point spacing is set to 8*7*7*8, and the sliver weight is set to 18 g / 5 m. S2 includes a first drawing process and a second drawing process. In the first drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 6.0 times, and the rear draft ratio is 1.

75. In the second drawing process, 6 strands are drawn together, the roller spacing is 16×9×20mm, the total draft ratio is 7.5 times, and the rear draft ratio is 1.

35. The two drawing processes are carried out at low speeds, not exceeding 240m / min.

2. The method for preparing a high-count composite yarn of fine denier modal and DTY filaments according to claim 1, characterized in that: In S3, during the roving process, the parameters are set as follows: basis weight 3.5g / 10m, spindle speed 650-750r / min, and roller spacing. 10×23×35mm, rear zone draw ratio 1.23, total draw ratio 8.

3.

3. The method for preparing a high-count composite yarn of fine denier modal and DTY filaments according to claim 1, characterized in that: In the S4 process, an 865 coated roller with medium-hard elasticity is selected, and the temperature and humidity of the yarn are controlled. The main process parameters of the yarn are set as follows: design twist coefficient 440; back zone understretch ratio 1.21; roller spacing 19*45mm.

4. The method for preparing a high-count composite yarn of fine denier modal and DTY filaments according to claim 3, characterized in that: In step S4, when controlling the temperature and humidity of the yarn, the yarn temperature is controlled to be 29℃-33℃.

5. The method for preparing a high-count composite yarn of fine denier modal and DTY filaments according to claim 3, characterized in that: The yarn after passing through the S5 winding is tested, and the test items include yarn linear density, coefficient of variation of weight per 100 meters, yarn twist, single yarn breaking strength, and coefficient of variation of single yarn breaking strength.

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