A long-staple cotton towel satin finishing process

Abstract

This invention belongs to the field of towel manufacturing technology, specifically a finishing process for long-staple cotton towels, including yarn treatment, fabric weaving, and dyeing. In this invention, after the long-staple cotton is produced into yarn, the yarn undergoes a preliminary dyeing process. The purpose of this is to create a clear color difference between the knotted areas and the normal areas. During subsequent weaving, when visually inspecting the fabric, the significant color difference allows for more accurate identification of the knotted areas. This enables precise napping treatment of the knotted areas in subsequent processing, improving the quality of the napping process. This reduces the impact of the knotted area on the quality of the finished towel, and can even prevent the appearance of white spots, ensuring the quality and comfort of the towel.

Description

Technical Field

[0001] This invention belongs to the field of towel production technology, specifically a long-staple cotton towel finishing process. Background Technology

[0002] Long-staple cotton is a common high-quality cotton variety used in textiles. Compared to ordinary cotton, it has the following characteristics:

[0003] Long fibers: Long-staple cotton has longer fibers, typically over 1.5 inches (38 mm). This makes the fibers more uniform and stronger, and the yarn produced after spinning is smoother.

[0004] Uniform fiber fineness: Long-staple cotton has a relatively uniform fiber fineness, meaning that the difference in fiber thickness is relatively small. This makes the yarn thickness more consistent during the spinning process, and easier to control and adjust.

[0005] High softness: Due to the characteristics of long fibers, long-staple cotton fabrics have better softness and feel. They are gentle on the skin and more comfortable.

[0006] High strength: Long-staple cotton has a tougher fiber structure and higher strength. This makes long-staple cotton fabrics more durable and less prone to wear and tear.

[0007] Good luster: Long-staple cotton fabric has a good luster, making the fabric look more shiny and textured.

[0008] Highly absorbent: Long-staple cotton fibers have excellent moisture absorption properties, which can quickly absorb and release moisture, keeping you dry and comfortable to wear.

[0009] Because of its long fiber length, long-staple cotton has many connections between fibers, which leads to the formation of knots during the spinning process. Knots are a key factor affecting the quality of the yarn. The presence of knots can easily cause white spots to appear in the fabric during the dyeing process, which greatly affects the quality of the fabric. Especially after it is made into towels, when the towel comes into contact with the face, it will affect the comfort of using the towel and thus affect the quality of the towel. Summary of the Invention

[0010] To overcome the shortcomings of existing technologies, this invention proposes a finishing process for long-staple cotton towels. This invention primarily addresses the problem of cotton knots easily forming in long-staple cotton fibers during spinning, which leads to uneven coloring during subsequent towel dyeing.

[0011] The technical solution adopted by this invention to solve its technical problem is: a long-staple cotton towel finishing process, including the following steps;

[0012] S1: Long-staple cotton raw material is fed into the equipment for spinning to produce yarn;

[0013] S2: The completed yarn is then put into the dyeing kettle for high-temperature dyeing for 1-2 hours, while maintaining the pressure inside the kettle at 1.5MPa. After dyeing, the yarn is dried at low temperature.

[0014] S3: Transfer the dyed yarn onto the loom, design the loom parameters according to the design requirements, control the loom's working process, and make the yarn interweave to form fabric.

[0015] S4: Visually inspect the produced fabric to identify the white areas caused by cotton knots, and then transfer the fabric to the napping machine to nap the white areas.

[0016] S5: Then, the napped fabric is put into the dyeing machine for dyeing. After the dyeing is completed, the fabric is dried.

[0017] S6: The dried fabric is then cut horizontally and vertically, and the cut edges are trimmed to complete the towel production.

[0018] This solution proposes a preliminary dyeing treatment of the yarn after long-staple cotton has been produced. The purpose of this is to create a clear color difference between the knotted areas and the normal areas. During subsequent weaving, the significant color difference allows for more accurate identification of the knots during visual inspection of the fabric. This enables precise napping treatment of the knotted areas in later processing, improving the quality of the napping process. Ultimately, this reduces the impact of knot location on the quality of the finished towel, and can even prevent the appearance of white spots, ensuring the quality and comfort of the towel.

[0019] Furthermore, dyeing the yarn at the yarn stage and then dyeing it again after the fabric is made can effectively improve the colorfastness of the towels. This process significantly enhances the quality of the towels and improves their durability. This double-dyeing method not only gives the towels vibrant colors but also allows them to maintain their original color and quality after multiple washes.

[0020] The spinning process in step S1 includes the following steps:

[0021] Q1: Long-staple cotton is fed into a cotton picker for opening and cleaning. The process parameters used are as follows: the speed of the picker is 500-700 r / min; the intermittent descent of the picker is 2 mm; and the distance of the picker extending out of the rib does not exceed 2 mm.

[0022] Q2: A carding machine is used to comb the opened material a second time. During the first combing process, the speed of the licker-in roller is reduced to 550-600 r / min and the cylinder speed is 250-300 r / min. During the second combing process, the speed of the licker-in roller is reduced to 450-500 r / min and the cylinder speed is 220-260 r / min.

[0023] The primary function of the carding process is to reduce neps and ensure textile quality. However, during carding, the number of short-staple cotton fibers increases, which is an unavoidable issue. To address this, a low-speed process is typically employed, reducing the speed of the licker-in roller and increasing the cylinder-to-licker-in roller speed ratio to minimize fiber damage and reduce the increase in short-staple fibers. This maximizes the retention of long-staple cotton fibers, ensuring the quality of the produced yarn.

[0024] By controlling the carding rate, the number of short fibers can be reduced, thus allowing for an increase in the number of carding passes while maintaining the short fiber content. Multiple carding passes improve the consistency of the long fiber texture, reducing the number of knots during yarn formation. This improves yarn quality and reduces the risk of uneven dyeing in subsequent towel production.

[0025] In summary, adopting a low-speed process and multiple carding methods can reduce the amount of short fibers while ensuring the retention rate of long-staple cotton fibers, thereby improving yarn quality and the dyeing and printing effects in towel production.

[0026] Q3: The combed cotton sliver is fed into the drawing device and drawn in one pass with built-in leveling, combining 8 slivers; before the drawing begins, the device is run at a low speed for 20-30 seconds, with a drawing length of not less than 5m; then the device is adjusted to a high speed.

[0027] Q4: The combined cotton sliver is then stretched until the sliver fineness reaches 2mm. The cotton sliver is mixed on the combined sliver by combining and stretching, and the looped sliver is shaped into a good sliver and wound onto the cotton sliver can.

[0028] Q5: Draft and twist the combined sliver to achieve a tensile strength of 2N; the total draft is 9.09 times; the back zone draft is 1.25 times; the twist coefficient is 150; the roving evenness CV is 3.75% and the elongation is 1.5%; if it does not meet the requirements, repeat the above steps for a second drawing process.

[0029] During the spinning process, cotton or other fibers, after pretreatment, form a long and narrow fiber bundle called evenness. Evenness is one of the raw materials for spinning, used to make the spindles on the spinning machine. CV value is one of the indicators that measures the fiber length and thickness in the evenness.

[0030] The CV value represents the degree of variation in fiber length within the yarn, specifically the ratio of the standard deviation to the average fiber length. A smaller CV value indicates less variation in fiber length, resulting in more uniform fiber length within the yarn. Conversely, a larger CV value indicates greater variation in fiber length, leading to less uniform fiber length within the yarn. By controlling the fiber length and CV value within the yarn, the quality and performance of the yarn can be adjusted during the spinning process.

[0031] Q6: The produced roving is further drafted and twisted to form fine yarn; then the fine yarn is wound to complete the yarn production.

[0032] Using nylon spindle tape instead of yarn spindle tape reduces spindle tape elongation, ensuring consistent spindle tape length without twisting, deviation, or collision with the spindle tape frame, thus reducing uneven yarn twist and strength. The winding process mainly involves removing harmful defects from the yarn and controlling the increase of hairiness, reducing the number of fine details on the yarn cones to improve the minimum strength of the yarn.

[0033] Replacing yarn spindles with nylon spindle belts can effectively reduce downtime caused by spindle slippage or breakage, thus improving production efficiency. Furthermore, using nylon spindle belts makes it easier to control belt tension, thereby better controlling yarn twist and strength unevenness.

[0034] The winding process is a crucial step in the spinning process. Winding operators need to remove harmful defects from the yarn, such as neps, thick spots, and thin spots, while also controlling the increase in yarn hairiness. These operations improve yarn quality and minimum strength, thereby enhancing the quality and value of the finished product. To achieve these goals, winding operators need to employ a series of operational techniques and precautions. First, they need to maintain a stable winding speed and select appropriate tension adjustment devices and yarn clearer parameters. Second, they need to regularly check the operation of the winding machine and promptly address any abnormalities, such as machine shutdowns or yarn breaks. Finally, winding operators also need to pay attention to the maintenance and upkeep of the winding machine to ensure its normal operation and extend its service life.

[0035] The napping process includes the following steps:

[0036] The woven fabric is processed by a napping machine to create a napped effect on its surface. During the napping process, the napping time is increased by 5-10 seconds for areas with knots detected by the visual inspection system to ensure that these knots are fully napped, making the towel surface smoother.

[0037] Since the visual inspection focuses on the location of cotton knots, the area with cotton knots is subjected to multiple, prolonged raising processes during the raising process. This loosens the cotton knots, allowing the dye to penetrate more easily into the fibers during the subsequent dyeing process, thereby improving the uniformity of dyeing and ultimately enhancing the quality of the dyeing.

[0038] Next, the surface of the towel after raising the pile is sheared using a shearing machine. By adjusting the parameters of the shearing machine, the pile length is controlled to be 5-10mm and the blade angle is 45°.

[0039] Because longer fibers can stick and entangle on the user's face during subsequent use, this increases the towel's shedding rate and affects its quality. Therefore, the shearing process trims the longer fibers generated during the pile-raising process to improve the towel's surface cleanliness and reduce shedding. Secondly, the length of the towel's fibers also affects its absorbency; the longer the fibers, the better the absorbency. Therefore, it is more appropriate to keep the fibers between 5 and 10 mm in length during shearing, which ensures both good absorbency and a suitable shedding rate.

[0040] The towel is then brushed using a brushing machine, during which the brush is parallel to the towel and the bristles penetrate 2-3mm into the towel.

[0041] Brushing towels makes the fibers softer and increases their absorbency. During the shearing process, the loose short fibers adhere to the surface of the towel. Brushing effectively removes impurities and excess lint from the towel surface, while making the fibers fluffier and softer, thus improving the towel's absorbency and breathability.

[0042] Finally, singeing is performed, using a flame to burn off any remaining lint on the surface of the towel. By precisely controlling the flame temperature and singeing time, it is ensured that the singeing process will not damage the towel fibers, while removing any remaining impurities and lint from the surface, making the towel cleaner and tidier.

[0043] The coloring process includes the following steps:

[0044] K1: Material preparation: Prepare dyes, auxiliaries, acids and alkalis, etc., according to the dyeing formula requirements;

[0045] Equipment preparation: Clean the dyeing tank and dyeing machine, and test run the equipment for more than 5 minutes;

[0046] By cleaning the dyeing tank to remove residues from the dyeing equipment, color bleeding during the dyeing process can be prevented. At the same time, by conducting trial runs of the equipment, dyeing interruptions caused by equipment failures can be prevented, thereby improving the success rate of dyeing.

[0047] K2: Dyeing Formula Preparation: The color of the fabric is detected and analyzed using color analysis equipment. Based on the test results and considering the depth and uniformity of the finished color, the proportion of the dyeing formula is determined.

[0048] Since the yarn is dyed on one side during the production process of the towels in this solution, the towel fabric woven from this yarn is already colored. Therefore, during the secondary dyeing process, it is necessary to first analyze and consider the color of the original yarn. Based on this, the dye is then mixed to ensure the accuracy of the color of the towel after dyeing, thereby improving the quality of the towel.

[0049] K3: Towel preparation:

[0050] Cleaning: Wash the towel to remove impurities and dirt;

[0051] Soaking: Soak the washed towel in water until it is completely wet, in preparation for dyeing;

[0052] After color testing, the towels are washed to remove impurities and improve the uniformity of dyeing. The towels are also moistened to prevent uneven dye absorption when the towels are first immersed in the dye.

[0053] K4: Staining process:

[0054] Adding dye: According to the formula requirements, the dye and corresponding auxiliaries are continuously added to the dyeing tank during the printing and dyeing process, stirred thoroughly and evenly, and the dye concentration is tested to control the dye addition rate.

[0055] Temperature control: According to the dyeing formula requirements, control the temperature of the dyeing tank between 100 and 130 degrees Celsius;

[0056] Add towels: Slowly place the damp towels into the dyeing tank, ensuring each towel is fully immersed in the dye solution. Stir to keep the dye solution uniform and maintain a constant temperature and pressure for 30-45 minutes;

[0057] pH adjustment: Add acid or alkali agents as needed during the staining process to adjust the pH value of the staining solution and ensure the staining effect;

[0058] Filtration: After dyeing, use a mesh or filter to remove dye residue, check the dye concentration, and re-mix the dye to facilitate the dyeing of the next batch.

[0059] Before dyeing, the towels are thoroughly moistened to ensure even dye absorption during the dyeing process. As dyeing continues, the dye concentration in the dyeing tank changes due to the continuous addition of towels. Therefore, to ensure a stable dye concentration throughout the dyeing process, real-time monitoring of the dye concentration is necessary. This provides a basis for subsequent dye additions, ensuring a stable dye concentration throughout the dyeing process, thereby controlling the dyeing degree of successive batches of towels and improving color consistency.

[0060] K5: Post-dyeing treatment:

[0061] Washing: Wash the dyed towels thoroughly to remove excess dye, auxiliaries, and other impurities; rinse several times until the drained water is clear.

[0062] Color fixing treatment: Spray an appropriate amount of color fixing agent or smoothing agent on the treated towel to improve color fastness and overall quality.

[0063] The dye is a thermosetting reactive dye.

[0064] During the dyeing process, thermosetting reactive dyes react chemically with the hydroxyl groups on the surface of cotton fibers to form covalent bonds, thus firmly binding the dye to the fibers. This covalent bonding allows the dye to penetrate deep into the fiber, resulting in a durable dyeing effect. Simultaneously, thermosetting reactive dyes can also form non-covalent interactions such as hydrogen bonds and van der Waals forces with cellulose fibers, further enhancing the dyeing fastness.

[0065] The dye contains 0.5% by weight of a foaming agent and 0.3% by weight of a softener.

[0066] By adding a foaming agent to the dye, a certain number of tiny air bubbles can be retained in the dye during the dyeing and stirring process. The presence of these tiny air bubbles allows them to penetrate between the yarn fibers, making the fibers fluffy and facilitating the dye to enter the fiber interior, thus improving the thoroughness of dyeing and the quality of dyeing. The foaming agent can be octyl alcohol polyoxyethylene ether (AE series) or octyl polyoxyethylene ether (EO series).

[0067] The pH value of the dyeing solution in step K4 is controlled between 9.5 and 10.5. When cotton fibers are dyed with thermosetting dyes, alkaline conditions can help improve the reaction rate and affinity between the dye and the fiber, as well as the penetration of the dye.

[0068] The beneficial effects of this invention are as follows:

[0069] 1. In this invention, after the long-staple cotton is produced into yarn, the yarn undergoes a preliminary dyeing treatment. The purpose of this is to create a clear color difference between the knotted areas and the normal areas. During subsequent weaving, when visually inspecting the fabric, the significant color difference allows for more accurate identification of the knotted areas. This enables precise napping treatment of the knotted areas in subsequent processing, improving the quality of the napping process. Consequently, the impact of the knotted area on the quality of the finished towel is reduced, and even the appearance of white spots can be avoided, ensuring the quality and comfort of the towel.

[0070] Furthermore, dyeing the yarn at the yarn stage and then dyeing it again after the fabric is made can effectively improve the colorfastness of the towels. This process significantly enhances the quality of the towels and improves their durability. This double-dyeing method not only gives the towels vibrant colors but also allows them to maintain their original color and quality after multiple washes.

[0071] 2. In this invention, controlling the carding rate reduces the amount of short fibers, thereby increasing the number of carding passes while ensuring the short fiber content. Multiple carding passes improve the consistency of the long fiber texture, reducing the number of knots during yarn formation. This improves yarn quality and reduces the risk of uneven dyeing in subsequent towel production. Employing a low-speed process and multiple carding passes reduces the amount of short fibers while maintaining the long-staple cotton fiber retention rate, thus improving yarn quality and the dyeing effect in towel production.

[0072] 3. In this invention, the location of cotton knots is determined by visual detection. During the napping process, the location of cotton knots is napped multiple times for a long time, which loosens the cotton knots. This allows the dye to penetrate more easily into the fibers during the subsequent dyeing process, thereby improving the uniformity of dyeing and thus improving the quality of dyeing. Attached Figure Description

[0073] The invention will now be further described with reference to the accompanying drawings.

[0074] Figure 1 This is a flowchart of the satin finishing process in the towel production process of this invention; Detailed Implementation

[0075] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0076] like Figure 1 As shown, a long-staple cotton towel finishing process includes the following steps;

[0077] S1: Long-staple cotton raw material is fed into the equipment for spinning to produce yarn;

[0078] S2: The completed yarn is then put into the dyeing kettle for high-temperature dyeing for 1-2 hours, while maintaining the pressure inside the kettle at 1.5MPa. After dyeing, the yarn is dried at low temperature.

[0079] S3: Transfer the dyed yarn onto the loom, design the loom parameters according to the design requirements, control the loom's working process, and make the yarn interweave to form fabric.

[0080] S4: Visually inspect the produced fabric to identify the white areas caused by cotton knots, and then transfer the fabric to the napping machine to nap the white areas.

[0081] S5: Then, the napped fabric is put into the dyeing machine for dyeing. After the dyeing is completed, the fabric is dried.

[0082] S6: The dried fabric is then cut horizontally and vertically, and the cut edges are trimmed to complete the towel production.

[0083] In operation, long-staple cotton, due to its fiber length advantage, has relatively tight inter-fiber bonds. However, this tight bond often leads to the formation of neps during the spinning process. As a key factor affecting yarn quality, neps, if present, can form white spots during dyeing, severely impacting fabric quality. Especially after being made into towels, the presence of neps directly affects comfort when the towel comes into contact with the face, further affecting the towel's quality.

[0084] To address this issue, we have proposed a solution. This solution advocates for a preliminary dyeing treatment of the yarn after long-staple cotton has been produced. The purpose of this is to create a clear color difference between the knotted areas and the normal areas. During subsequent weaving, the significant color difference allows for more accurate identification of the knots during visual inspection of the fabric. This enables precise napping treatment of the knotted areas in later processing, improving the quality of the napping process. Consequently, the impact of knot location on the quality of the finished towel can be reduced, and even the appearance of white spots can be avoided, ensuring the quality and comfort of the towel.

[0085] Furthermore, dyeing the yarn at the yarn stage and then dyeing it again after the fabric is made can effectively improve the colorfastness of the towels. This process significantly enhances the quality of the towels and improves their durability. This double-dyeing method not only gives the towels vibrant colors but also allows them to maintain their original color and quality after multiple washes.

[0086] When implementing this solution, we need to focus on several key aspects. First, the dyeing process for the yarn requires selecting appropriate dyes and techniques to ensure the dyeing effect clearly reflects the location of the knots. Second, the dyed yarn needs careful inspection to confirm whether the location of the knots and the color difference are sufficiently obvious. If the color difference is insufficient, it may be necessary to adjust the dyeing process or select different dyes. Furthermore, the napping process for the knot areas also requires appropriate pressure and time to ensure that the napping effect effectively improves the quality and comfort of the towel.

[0087] The spinning process in step S1 includes the following steps:

[0088] Q1: Long-staple cotton is fed into a cotton picker for opening and cleaning. The process parameters used are as follows: the speed of the picker is 500-700 r / min; the intermittent descent of the picker is 2 mm; and the distance of the picker extending out of the rib does not exceed 2 mm.

[0089] Q2: A carding machine is used to comb the opened material a second time. During the first combing process, the speed of the licker-in roller is reduced to 550-600 r / min and the cylinder speed is 250-300 r / min. During the second combing process, the speed of the licker-in roller is reduced to 450-500 r / min and the cylinder speed is 220-260 r / min.

[0090] The primary function of the carding process is to reduce neps and ensure textile quality. However, during carding, the number of short-staple cotton fibers increases, which is an unavoidable issue. To address this, a low-speed process is typically employed, reducing the speed of the licker-in roller and increasing the cylinder-to-licker-in roller speed ratio to minimize fiber damage and reduce the increase in short-staple fibers. This maximizes the retention of long-staple cotton fibers, ensuring the quality of the produced yarn.

[0091] By controlling the carding rate, the number of short fibers can be reduced, thus allowing for an increase in the number of carding passes while maintaining the short fiber content. Multiple carding passes improve the consistency of the long fiber texture, reducing the number of knots during yarn formation. This improves yarn quality and reduces the risk of uneven dyeing in subsequent towel production.

[0092] In summary, adopting a low-speed process and multiple carding methods can reduce the amount of short fibers while ensuring the retention rate of long-staple cotton fibers, thereby improving yarn quality and the dyeing and printing effects in towel production.

[0093] Q3: The combed cotton sliver is fed into the drawing device and drawn in one pass with built-in leveling, combining 8 slivers; before the drawing begins, the device is run at a low speed for 20-30 seconds, with a drawing length of not less than 5m; then the device is adjusted to a high speed.

[0094] Q4: The combined cotton sliver is then stretched until the sliver fineness reaches 2mm. The cotton sliver is mixed on the combined sliver by combining and stretching, and the looped sliver is shaped into a good sliver and wound onto the cotton sliver can.

[0095] Q5: Draft and twist the combined sliver to achieve a tensile strength of 2N; the total draft is 9.09 times; the back zone draft is 1.25 times; the twist coefficient is 150; the roving evenness CV is 3.75% and the elongation is 1.5%; if it does not meet the requirements, repeat the above steps for a second drawing process.

[0096] During the spinning process, cotton or other fibers, after pretreatment, form a long and narrow fiber bundle called evenness. Evenness is one of the raw materials for spinning, used to make the spindles on the spinning machine. CV value is one of the indicators that measures the fiber length and thickness in the evenness.

[0097] The CV value represents the degree of variation in fiber length within the yarn, specifically the ratio of the standard deviation to the average fiber length. A smaller CV value indicates less variation in fiber length, resulting in more uniform fiber length within the yarn. Conversely, a larger CV value indicates greater variation in fiber length, leading to less uniform fiber length within the yarn. By controlling the fiber length and CV value within the yarn, the quality and performance of the yarn can be adjusted during the spinning process.

[0098] Q6: The produced roving is further drafted and twisted to form fine yarn; then the fine yarn is wound to complete the yarn production.

[0099] Using nylon spindle tape instead of yarn spindle tape reduces spindle tape elongation, ensuring consistent spindle tape length without twisting, deviation, or collision with the spindle tape frame, thus reducing uneven yarn twist and strength. The winding process mainly involves removing harmful defects from the yarn and controlling the increase of hairiness, reducing the number of fine details on the yarn cones to improve the minimum strength of the yarn.

[0100] Replacing yarn spindles with nylon spindle belts can effectively reduce downtime caused by spindle slippage or breakage, thus improving production efficiency. Furthermore, using nylon spindle belts makes it easier to control belt tension, thereby better controlling yarn twist and strength unevenness.

[0101] The winding process is a crucial step in the spinning process. Winding operators need to remove harmful defects from the yarn, such as neps, thick spots, and thin spots, while also controlling the increase in yarn hairiness. These operations improve yarn quality and minimum strength, thereby enhancing the quality and value of the finished product. To achieve these goals, winding operators need to employ a series of operational techniques and precautions. First, they need to maintain a stable winding speed and select appropriate tension adjustment devices and yarn clearer parameters. Second, they need to regularly check the operation of the winding machine and promptly address any abnormalities, such as machine shutdowns or yarn breaks. Finally, winding operators also need to pay attention to the maintenance and upkeep of the winding machine to ensure its normal operation and extend its service life.

[0102] The napping process includes the following steps:

[0103] The woven fabric is processed by a napping machine to create a napped effect on its surface. During the napping process, the napping time is increased by 5-10 seconds for areas with knots detected by the visual inspection system to ensure that these knots are fully napped, making the towel surface smoother.

[0104] Since the visual inspection focuses on the location of cotton knots, the area with cotton knots is subjected to multiple, prolonged raising processes during the raising process. This loosens the cotton knots, allowing the dye to penetrate more easily into the fibers during the subsequent dyeing process, thereby improving the uniformity of dyeing and ultimately enhancing the quality of the dyeing.

[0105] Next, the surface of the towel after raising the pile is sheared using a shearing machine. By adjusting the parameters of the shearing machine, the pile length is controlled to be 5-10mm and the blade angle is 45°.

[0106] Because longer fibers can stick and entangle on the user's face during subsequent use, this increases the towel's shedding rate and affects its quality. Therefore, the shearing process trims the longer fibers generated during the pile-forming process to improve the towel's surface cleanliness and reduce shedding. Secondly, the length of the towel's fibers also affects its absorbency; the longer the fibers, the better the absorbency. Therefore, it is more appropriate to keep the fibers between 5 and 10 mm in length during shearing to ensure both absorbency and a suitable shedding rate.

[0107] The towel is then brushed using a brushing machine, during which the brush is parallel to the towel and the bristles penetrate 2-3mm into the towel.

[0108] Brushing towels makes the fibers softer and increases their absorbency. During the shearing process, the loose short fibers adhere to the surface of the towel. Brushing effectively removes impurities and excess lint from the towel surface, while making the fibers fluffier and softer, thus improving the towel's absorbency and breathability.

[0109] Finally, singeing is performed, using a flame to burn off any remaining lint on the surface of the towel. By precisely controlling the flame temperature and singeing time, it is ensured that the singeing process will not damage the towel fibers, while removing any remaining impurities and lint from the surface, making the towel cleaner and tidier.

[0110] The coloring process includes the following steps:

[0111] K1: Material preparation: Prepare dyes, auxiliaries, acids and alkalis, etc., according to the dyeing formula requirements;

[0112] Equipment preparation: Clean the dyeing tank and dyeing machine, and test run the equipment for more than 5 minutes;

[0113] By cleaning the dyeing tank to remove residues from the dyeing equipment, color bleeding during the dyeing process can be prevented. At the same time, by conducting trial runs of the equipment, dyeing interruptions caused by equipment failures can be prevented, thereby improving the success rate of dyeing.

[0114] K2: Dyeing Formula Preparation: The color of the fabric is detected and analyzed using color analysis equipment. Based on the test results and considering the depth and uniformity of the finished color, the proportion of the dyeing formula is determined.

[0115] Since the yarn is dyed on one side during the production process of the towels in this solution, the towel fabric woven from this yarn is already colored. Therefore, during the secondary dyeing process, it is necessary to first analyze and consider the color of the original yarn. Based on this, the dye is then mixed to ensure the accuracy of the color of the towel after dyeing, thereby improving the quality of the towel.

[0116] K3: Towel preparation:

[0117] Cleaning: Wash the towel to remove impurities and dirt;

[0118] Soaking: Soak the washed towel in water until it is completely wet, in preparation for dyeing;

[0119] After color testing, the towels are washed to remove impurities and improve the uniformity of dyeing. The towels are also moistened to prevent uneven dye absorption when the towels are first immersed in the dye.

[0120] K4: Staining process:

[0121] Adding dye: According to the formula requirements, the dye and corresponding auxiliaries are continuously added to the dyeing tank during the printing and dyeing process, stirred thoroughly and evenly, and the dye concentration is tested to control the dye addition rate.

[0122] Temperature control: According to the dyeing formula requirements, control the temperature of the dyeing tank between 100 and 130 degrees Celsius;

[0123] Add towels: Slowly place the damp towels into the dyeing tank, ensuring each towel is fully immersed in the dye solution. Stir to keep the dye solution uniform and maintain a constant temperature and pressure for 30-45 minutes;

[0124] pH adjustment: Add acid or alkali agents as needed during the staining process to adjust the pH value of the staining solution and ensure the staining effect;

[0125] Filtration: After dyeing, use a mesh or filter to remove dye residue, check the dye concentration, and re-mix the dye to facilitate the dyeing of the next batch.

[0126] Before dyeing, the towels are thoroughly moistened to ensure even dye absorption during the dyeing process. As dyeing continues, the dye concentration in the dyeing tank changes due to the continuous addition of towels. Therefore, to ensure a stable dye concentration throughout the dyeing process, real-time monitoring of the dye concentration is necessary. This provides a basis for subsequent dye additions, ensuring a stable dye concentration throughout the dyeing process, thereby controlling the dyeing degree of successive batches of towels and improving color consistency.

[0127] In addition to monitoring dye concentration, the dampness of the towel also needs to be considered in relation to the dyeing effect. If the towel is too wet or too dry, it will affect the absorption and diffusion of the dye, thus impacting the final dyeing result. Therefore, the towel needs to be properly moistened before dyeing to ensure it can fully absorb the dye during the dyeing process and to ensure more even dye diffusion.

[0128] In summary, to improve the consistency of towel color, we need to employ an efficient detection method to monitor the dye concentration in the dyeing tank in real time (for example, a dye concentration sensor can be used to measure the dye concentration, and then the measured data can be transmitted to the control system. The control system can automatically adjust the dye supply based on the measured data, thereby maintaining a stable dye concentration. Additionally, computer vision technology can be used to automatically inspect the dyed fabric to determine whether the dyeing effect and quality meet the requirements), and careful control of the towel's moisture level is also necessary. Only in this way can we ensure that the dye concentration remains stable during the dyeing process, thus ensuring that the dyeing degree of towels from different batches is consistent.

[0129] K5: Post-dyeing treatment:

[0130] Washing: Wash the dyed towels thoroughly to remove excess dye, auxiliaries, and other impurities; rinse several times until the drained water is clear.

[0131] Color fixing treatment: Spray an appropriate amount of color fixing agent or smoothing agent on the treated towel to improve color fastness and overall quality.

[0132] During processing, color-fixing agents are chemical auxiliaries used to improve the color durability of dyed fabrics. They maintain color vibrancy and longevity by forming a thin film on the fiber surface, preventing dye from leaching from the fabric. Color-fixing agents are commonly used in textile finishing processes to increase product quality and added value.

[0133] The main function of a color-fixing agent is to fix the color of dye on fabric, preventing it from fading or changing color. This auxiliary agent is suitable for various types of dyes, including natural dyes, acid dyes, and reactive dyes. After using a color-fixing agent, dyed fabrics can maintain their color vibrancy, abrasion resistance, and washability, thereby improving product quality and added value.

[0134] The dye is a thermosetting reactive dye.

[0135] When in use, cotton fiber is a natural fiber mainly composed of cellulose, and its chemical structure contains many hydroxyl (OH) functional groups. Thermosetting reactive dyes have reactive groups that react with hydroxyl groups, such as amino reactive groups and dichlorotriazine reactive groups.

[0136] During the dyeing process, thermosetting reactive dyes react chemically with the hydroxyl groups on the surface of cotton fibers to form covalent bonds, thus firmly binding the dye to the fibers. This covalent bonding allows the dye to penetrate deep into the fiber, resulting in a durable dyeing effect. Simultaneously, thermosetting reactive dyes can also form non-covalent interactions such as hydrogen bonds and van der Waals forces with cellulose fibers, further enhancing the dyeing fastness.

[0137] Furthermore, thermosetting reactive dyes require a thermosetting reaction under specific temperature and pH conditions during the dyeing process to ensure a stronger bond between the dye and the fiber. This thermosetting reaction improves the wash fastness, rubbing fastness, and light fastness of the dye, ensuring that the dyeing effect remains stable even after long-term use and multiple washes.

[0138] Therefore, thermosetting reactive dyes can establish a strong dyeing bond with cotton fibers, while also possessing good durability and dyeing effect, making them suitable for dyeing cotton fibers.

[0139] Thermosetting reactive dyes have the following characteristics: easy penetration: Thermosetting reactive dyes have a small molecular structure, allowing them to quickly penetrate into cellulose and synthetic fibers; good affinity: Thermosetting reactive dyes have a chemical structure that matches cellulose and synthetic fibers, enabling them to effectively react chemically with the fibers and firmly bind to them; durability: Thermosetting reactive dyes bind to fibers through a thermosetting reaction, forming a permanent dyeing effect with good wash fastness, rubbing fastness, and light fastness; easy process control: Thermosetting reactive dyes require relatively high control over factors such as temperature, pH value, and time during the dyeing process, but they also provide a wider range of dyeing control capabilities, enabling the achievement of rich and varied color effects.

[0140] The dye contains 0.5% by weight of a foaming agent and 0.3% by weight of a softener.

[0141] By adding a foaming agent to the dye, a certain number of tiny air bubbles can be retained in the dye during the dyeing and stirring process. The presence of these tiny air bubbles allows them to penetrate between the yarn fibers, making the fibers fluffy and facilitating the dye to enter the fiber interior, thus improving the thoroughness of dyeing and the quality of dyeing. The foaming agent can be octyl alcohol polyoxyethylene ether (AE series) or octyl polyoxyethylene ether (EO series).

[0142] The pH value of the staining solution in step K4 is controlled between 9.5 and 10.5.

[0143] When cotton fibers are dyed with thermosetting dyes, alkaline conditions can help increase the reaction rate and affinity between the dye and the fiber, as well as the dye's penetration. Therefore, thermosetting dyes generally react and bind better with cotton fibers when dyeing is carried out in a pH range slightly above neutral.

[0144] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A finishing process for long-staple cotton towels, characterized in that: Includes the following steps; S1: Long-staple cotton raw material is fed into the equipment for spinning to produce yarn; S2: The completed yarn is then put into the dyeing kettle for high-temperature dyeing for 1-2 hours, while maintaining the pressure inside the kettle at 1.5MPa. After dyeing, the yarn is dried at low temperature. S3: Transfer the dyed yarn onto the loom, design the loom parameters according to the design requirements, control the loom's working process, and make the yarn interweave to form fabric. S4: Visually inspect the produced fabric to identify the white areas caused by cotton knots, and then transfer the fabric to the napping machine to nap the white areas. S5: Then, the napped fabric is put into the dyeing machine for dyeing. After the dyeing is completed, the fabric is dried. S6: The dried fabric is then cut horizontally and vertically, and the cut edges are trimmed to complete the towel production. The napping process includes the following steps: The woven fabric is processed by a napping machine to create a napped effect on its surface. During the napping process, the napping time is increased by 5-10 seconds for areas with knots detected by the visual inspection system to ensure that these knots are fully napped, making the towel surface smoother. Next, the surface of the towel after raising the pile is sheared using a shearing machine. By adjusting the parameters of the shearing machine, the pile length is controlled to be 5-10mm and the blade angle is 45°. The towel is then brushed using a brushing machine, during which the brush is parallel to the towel and the bristles penetrate 2-3mm into the towel. Finally, singeing is performed, using a flame to burn off any remaining lint on the surface of the towel. By precisely controlling the flame temperature and singeing time, it is ensured that the singeing process will not damage the towel fibers, while removing any remaining impurities and lint from the surface, making the towel cleaner and tidier.

2. The finishing process for long-staple cotton towels according to claim 1, characterized in that: The spinning process in step S1 includes the following steps: Q1: Long-staple cotton is fed into a cotton picker for opening and cleaning. The process parameters used are as follows: the speed of the picker is 500-700 r / min; the intermittent descent of the picker is 2 mm; and the distance of the picker extending out of the rib does not exceed 2 mm. Q2: A carding machine is used to comb the opened material a second time. During the first combing process, the speed of the licker-in roller is reduced to 550-600 r / min and the cylinder speed is 250-300 r / min. During the second combing process, the speed of the licker-in roller is reduced to 450-500 r / min and the cylinder speed is 220-260 r / min. Q3: The combed cotton sliver is fed into the drawing machine and drawn in one pass with built-in leveling, combining 8 slivers; before the drawing begins, the machine is run at a low speed for 20-30 seconds, with a drawing length of no less than 5m; then the machine is adjusted to a high speed. Q4: The combined cotton sliver is then stretched until the sliver fineness reaches 2mm. The cotton sliver is mixed on the combined sliver by combining and stretching, and the looped sliver is shaped into a good sliver and wound onto the cotton sliver can. Q5: Draft and twist the combined sliver to achieve a tensile strength of 2N; the total draft is 9.09 times; the back zone draft is 1.25 times; the twist coefficient is 150; the roving evenness CV is 3.75% and the elongation is 1.5%; if it does not meet the requirements, repeat the above steps for a second drawing process. Q6: The produced roving is further drafted and twisted to form fine yarn; then the fine yarn is wound to complete the yarn production.

3. The satin finishing process for long-staple cotton towels according to claim 2, characterized in that: The coloring process includes the following steps: K1: Material preparation: Prepare dyes, auxiliaries, acids and alkalis according to the dyeing formula requirements; Equipment preparation: Clean the dyeing tank and dyeing machine, and test run the equipment for more than 5 minutes; K2: Dyeing Formula Preparation: The color of the fabric is tested and analyzed using color analysis equipment, and the proportion of the dyeing formula is determined based on the test results and considering the depth and uniformity of the finished color. K3: Towel preparation: Cleaning: Wash the towel to remove impurities and dirt; Soaking: Soak the washed towel in water until it is completely wet, in preparation for dyeing; K4: Staining process: Adding dye: According to the formula requirements, the dye and corresponding auxiliaries are continuously added to the dyeing tank during the printing and dyeing process, stirred thoroughly and evenly, and the dye concentration is tested to control the dye addition rate. Temperature control: According to the dyeing formula requirements, control the temperature of the dyeing tank between 100-130 degrees Celsius; Add towels: Slowly place the damp towels into the dyeing tank, ensuring that each towel is fully soaked in the dye solution; stir to keep the dye solution uniform, and maintain a constant temperature and pressure for 30-45 minutes; pH adjustment: Add acid or alkali agents as needed during the staining process to adjust the pH value of the staining solution and ensure the staining effect; Filtration: After dyeing, use a mesh or filter to remove dye residue, check the dye concentration, and re-mix the dye to facilitate the dyeing of the next batch. K5: Post-dyeing treatment: Washing: Wash the dyed towels thoroughly to remove excess dye, auxiliaries, and other impurities; rinse several times until the drained water is clear; Color fixing treatment: Spray an appropriate amount of color fixing agent or smoothing agent on the treated towel to improve color fastness and overall quality.

4. The finishing process for long-staple cotton towels according to claim 3, characterized in that: The dye is a thermosetting reactive dye.

5. The long-staple cotton towel satin finishing process according to claim 4, characterized in that: The dye contains 0.5% by weight of a foaming agent and 0.3% by weight of a softening agent.

6. The finishing process for long-staple cotton towels according to claim 5, characterized in that: The pH value of the staining solution in step K4 is controlled between 9.5 and 10.5.

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