Rotor spinning linen-like yarn and production method thereof

Abstract

The invention belongs to the technical field of yarn preparation, and particularly relates to rotor spinning linen-like yarn and a production method thereof. The production method of the rotor spinning linen-like yarn comprises the following steps that firstly, the cotton carding process is adjusted, fiber rods containing controllable neps are prepared, and drawn slivers obtained after the fiber rods containing the controllable neps and combed slivers are combined twice serve as rotor spinning raw materials; and the drawn slivers are accurately controlled by a servo motor dynamic bamboo joint control system and then enter a rotor spinning machine through a modified cotton feeding plate and a cotton passing channel for drafting, twisting and composite spinning, and the linen-like yarn is obtained. Through structural modification and process design of the carding machine, nep slivers are prepared. According to the production method of the rotor spinning linen-like yarn, the equipment running rate is larger than or equal to 95.2%, meanwhile, compared with ring spinning, the roving and spooling procedures are reduced, the yarn production efficiency is improved, the production and transportation cost is reduced, and the yarn produced through the production method has natural textures and is good in linen-like effect.

Description

Technical Field

[0001] This invention belongs to the field of yarn preparation technology, specifically relating to rotor-spun linen-like yarn and its production method. Background Technology

[0002] Natural hemp fibers (such as flax and hemp) are increasingly in demand in the high-end textile fabric sector due to their excellent moisture absorption and breathability, natural antibacterial properties, and environmental friendliness. However, their inherent defects, such as coarse and stiff fibers, poor spinnability, and high processing costs, severely restrict their large-scale application. To compensate for the shortcomings of natural hemp fibers, the development of hemp-like yarns has become an important research direction in the industry.

[0003] Traditional linen-like yarns primarily rely on ring spinning technology, mimicking the style of linen yarn through process adjustments or blending. However, this technology has significant limitations: low production efficiency, high yarn hairiness, and a stiff, unnatural linen texture, making it difficult to achieve the natural distribution of coarse and fine fibers characteristic of linen. Furthermore, the high cost of ring-spun linen-like yarns restricts the product's market competitiveness.

[0004] Rotor spinning technology, with its advantages of high speed, high output, and short process, is considered a potential path to reduce costs and increase efficiency in linen-like yarn production. However, conventional rotor spinning systems produce yarns with a uniform structure, making it difficult to directly form the natural slubs and irregular thick and thin areas required for linen-like fabrics. Existing technologies attempt to artificially create slubs through post-processing (such as mechanical beating and chemical finishing), but this suffers from problems such as complex processes, high energy consumption, fiber damage, and poor durability of the effect. Some improvement solutions focus on equipment modification; for example, patent CN115772724A proposes embedding oily adhesive dots in the accumulation tank of the spinning cup to form linen-like nodes by interfering with fiber distribution. However, this solution has significant drawbacks: the oily adhesive dots are prone to drying and falling off, leading to fluctuations in the linen-like effect during production and making it difficult to guarantee product consistency; the fixed position of the adhesive dots results in a strong regularity in the distribution of linen-like nodes in the yarn, which easily produces regular unevenness on the fabric surface after weaving, seriously affecting the appearance quality and grade of the fabric.

[0005] In addition, existing rotor spinning technology for imitating linen generally faces common technical bottlenecks such as insufficient control of cotton knots, unnatural slub shapes, and poor randomness in the thickness and fineness of the fibers.

[0006] To optimize blended raw materials, existing technologies have explored blending schemes for viscose and hemp fibers. At the equipment level, improvements have been made to cotton feeding devices and spinning machine structures, or the development of functional fibers has been undertaken. However, these technologies mostly focus on a single aspect (raw materials, equipment, or process), lacking collaborative and innovative design for raw material pretreatment, core rotor spinning process parameters (such as carding speed, twist, and spinneret negative pressure), and key components (such as carding rollers and twist-blocking heads). This makes it difficult to simultaneously achieve low cost, high fidelity, and stability in efficient continuous production. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for producing rotor-spun linen-like yarn with an equipment operating rate of ≥95.2%. At the same time, compared with ring spinning, it reduces the roving and winding processes, improves yarn production efficiency, and reduces production and transportation costs. The yarn produced by the production method of the present invention has a natural texture and a good linen-like effect.

[0008] The production method of rotor-spun imitation linen yarn according to the present invention includes the following steps: The method first adjusts the carding process to prepare a fiber sliver containing controllable neps, and uses the sliver containing controllable neps and the combed sliver after two passes as the raw material for rotor spinning; the sliver is precisely controlled by a servo motor dynamic slub control system, and then enters the rotor spinning machine for drafting and twisting through a modified feed plate and cotton passage, and is then spun into composite yarn to obtain the imitation linen yarn.

[0009] The preparation of the fiber sliver containing controllable neps includes: by modifying the structure and designing the process of the carding machine, a fiber sliver containing controllable neps is prepared, wherein the number of neps is controlled to be above 1500 per meter.

[0010] Six fiber slivers containing controllable neps are combined with six combed slivers at a mass ratio of 1:4 to 1:5, and then processed using a four-up-three-down drafting device, with the draft ratio controlled within the range of 5-7.2 times. The basis weight of the finished sliver is 18-30 g / 5m.

[0011] Structural modifications and process design of the carding machine: a) Increase the distance between the licker-in roller and the cylinder to 0.20-0.23mm to reduce fiber transfer from the licker-in roller to the cylinder, allowing untransferred fibers to rub against newly fed fibers, which is beneficial for nip formation; b) Reduce the licker-in roller speed to 780-852rpm to reduce the carding effect; c) Reverse the left and right movable cover plates, increasing the four spacing points between the cylinder and the movable cover plates to 0.51, 0.41, 0.41, and 0.76mm; d) Reverse the left and right fixed cover plates. After reversing the cover plates, the fibers between the cylinder and the cover plates change from carding to rubbing to form nipples. Reversing the installation here refers to rotating the cover plates left and right. Under normal installation conditions, the needle surface of the cover plate faces the needle surface of the cylinder; after reversing, the needle surface of the cover plate is opposite to its original direction and faces the same direction as the cylinder needle surface.

[0012] The dynamic slub control system prioritizes the establishment of a database containing 512 sets of slub characteristic parameters. Through servo motor linkage, it precisely controls the step-by-step feeding of cotton sliver to achieve 512 characteristic combinations, including base yarn length L=100-500mm, slub length D=80-100mm, and slub thickness increment K=50%-200%. The servo motor linkage control is used to achieve precise step-by-step adjustment of the feed speed of the rotor spinning machine.

[0013] An arc-shaped groove is set through the working surface of the cotton feeding plate, with a height of 8mm and a maximum depth of 1.2mm from the working surface of the cotton feeding plate. This changes the fiber transfer efficiency and promotes the formation of neps when the cotton sliver is fed into the cotton feeding plate by the feeding roller.

[0014] A cylindrical blocking block with a diameter of 1 mm and an extension length of 1.5 mm is installed inside the cotton passage. It plays a certain role in blocking the fibers after the combing roller has combed the fibers. At the same time, the fibers hanging on the blocking block form cotton knots.

[0015] The process parameters for composite spinning are as follows: Rotor speed is 55,000-60,000 rpm, which creates an irregular internal structure in the yarn through high-speed rotation, simulating the grainy texture of linen. The carding roller speed is set to 6,000-8,000 rpm to control the carding intensity and reduce fiber damage. The twist coefficient is controlled at 450-500 to ensure yarn strength while reducing the hairiness coefficient and enhancing the linen-like appearance. The spinning environment humidity is maintained at 55%-65% to reduce static electricity and improve fiber cohesion.

[0016] A linen-like yarn is produced by the aforementioned rotor-spun linen-like yarn production method.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) The method for producing rotor-spun linen-like yarn of the present invention develops low-cost yarn with high linen-like effect through raw material processing, synergistic optimization of process parameters and equipment modification.

[0018] (2) This invention only modifies the cotton feeding structure and cotton passage of the rotor spinning machine and, with the help of digital control, does not affect the drafting and twisting mechanism, does not damage the dynamic balance of the machine, and has not generated noise or abnormal heat.

[0019] (3) The imitation linen yarn produced by the method of the present invention has the natural texture of linen fiber, moisture absorption and breathability, less hair and high strength. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the rotor spinning cotton feeding mechanism before the modification.

[0021] Figure 2 This is a schematic diagram of the improved rotor spinning cotton feeding mechanism of the present invention.

[0022] Figure 3 This is a schematic diagram of the cotton passage after the improvement of the present invention.

[0023] In the diagram: 1. Working surface of the feed plate; 2. Groove; 3. Feed roller; 4. Block; 5. Fibers hanging on the block; 6. Fibers after being combed by the carding roller; 7. Cotton passage. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments.

[0025] The raw materials and additives used in the following examples and comparative examples are all commercially available products.

[0026] like Figure 3 The cotton passage 7 is provided with a blocking block 4, which is cylindrical with a diameter of 1 mm and an extension length of 1.5 mm. It plays a certain role in blocking the fibers 6 after combing by the combing roller. At the same time, the fibers 5 hanging on the blocking block form cotton knots.

[0027] compared to Figure 1 Before the modification, the rotor spinning feeder was improved as follows: Figure 2 As shown, an arc-shaped groove 2 is provided in the cotton feeding plate, penetrating the working surface 1 of the cotton feeding plate. The groove 2 has a height of 8mm and a maximum depth of 1.2mm from the working surface 1 of the cotton feeding plate. When the cotton sliver is fed into the cotton feeding plate through the cotton feeding roller 3, the fiber transfer efficiency is changed, promoting the formation of cotton knots.

[0028] Example 1 The method for producing rotor-spun linen-like yarn includes the following steps: Producing 10Ne linen-like yarn. The raw material is 100% American short-staple cotton. 80% of the short-staple cotton is processed into sliver using a JWF1211A carding machine. The sliver is made by combining 6 slivers together. The drawing frame has a 4-up-3-down drafting configuration, with the draft ratio controlled at 6.113. After being prepared for combing, it enters the combing section, with the cotton waste rate controlled at 15%, to obtain the combed sliver.

[0029] Modify the JWF1211A carding machine, set the gap between the licker-in and the cylinder to 0.20mm, set the licker-in speed to 812rpm, reverse the movable cover plate, set the cylinder-movable cover plate gap to 0.51, 0.41, 0.41, and 0.76mm, reverse the fixed cover plate, feed in 20% fine cotton, and after carding, obtain a fiber sliver containing controllable neps, with a nep count of 1507 neps / m.

[0030] The fiber sliver containing controllable neps is combined with the combed sliver at a ratio of 1:4 to obtain a finished sliver with a basis weight of 20g / 5m. The obtained finished sliver is fed into a BD7 rotor spinning machine, in which an arc-shaped groove 2 is set on the working surface of the cotton board, with a groove height of 8mm and a maximum depth of 1.2mm from the working surface. After carding, the sliver passes through a modified cotton passage 7 and enters the rotor for drafting and twisting after passing through the blocking block 4. The rotor speed is set to 60,000rpm, the carding roller speed to 6,000rpm, the twist coefficient to 450, and the spinning environment humidity to be maintained at 60%. The dynamic slub control system prioritizes the establishment of a database containing 512 sets of slub characteristic parameters, and precisely controls the step feeding of the sliver through servo motor linkage. The slub parameters are adjusted to base yarn length L = 100-500mm, slub length D = 80-100mm, and thickness increment K = 50%-150%.

[0031] Example 2 The method for producing rotor-spun linen-like yarn includes the following steps: Producing 21Ne linen-like yarn. The raw material is 100% American short-staple cotton. 83.3% of the short-staple cotton is processed into sliver using a JWF1211A carding machine. Six slivers are combined, and the drawing frame has a four-up, three-down drafting configuration, with a draft ratio controlled at 6.113. Afterward, it enters the combing process, with a cotton waste rate controlled at 15%, yielding a combed sliver.

[0032] 16.7% fine cotton was processed by a JWF1211A carding machine with the licker-in roller and cylinder spacing set to 0.22mm, the licker-in roller speed set to 780rpm, the movable cover plate was reversed, and the cylinder-movable cover plate spacing was set to 0.51, 0.41, 0.41, and 0.76mm. The fixed cover plate was reversed to obtain a fiber sliver containing controllable neps with a nep count of 1583 neps / m.

[0033] The fiber sliver containing controllable neps is combined with the combed sliver at a ratio of 1:5 to obtain a finished sliver with a basis weight of 18g / 5m. The obtained finished sliver is fed into a BD7 rotor spinning machine, in which an arc-shaped groove 2 is set on the working surface of the cotton board, with a groove height of 8mm and a maximum depth of 1.2mm from the working surface. After carding, the sliver passes through a modified cotton passage 7 and enters the rotor for drafting and twisting after passing through a blocking block 4. The rotor speed is set to 55,000 rpm, the carding roller speed to 6,000 rpm, and the twist coefficient to 500; the spinning environment humidity is maintained at 60%; the dynamic slub control system prioritizes the establishment of a database containing 512 sets of slub characteristic parameters, and uses a servo motor to precisely control the step feeding of the sliver. The slub parameters are adjusted to base yarn length L = 100-500mm, slub length D = 80-100mm, and thickness increment K = 100%-150%.

[0034] Example 3 The method for producing rotor-spun linen-like yarn includes the following steps: The difference from Example 2 lies in the raw material being changed to 70% American short-staple cotton / 30% G100 Tencel fiber. 55% of the short-staple cotton is combed to prepare a combed sliver, and 15% of the short-staple cotton is used to prepare a fiber sliver containing controllable neps. The G100 Tencel is used to prepare a raw sliver, which is then combined twice at a ratio of 15% raw sliver containing neps / 55% combed American short-staple cotton / 30% G100 Tencel. The combined sliver is then fed into a BD7 rotor spinning machine. The carding machine, drawing frame, and BD7 rotor spinning machine process and equipment parameters are the same as in Example 2, and the spinning environment humidity is maintained at 60%. A 21Ne linen-like yarn is obtained.

[0035] Comparative Example 1 The yarn used is 100% hemp yarn spun from 21Ne compact Sirospun yarn, with a twist coefficient of 500.

[0036] Comparative Example 2 The difference from Example 2 is that 100% fine cotton combed slivers are used for the second blending.

[0037] Comparative Example 3 The difference from Example 2 is that the dynamic slub control system is turned off, so that the sliver is fed into the BD7 rotor spinning machine at a uniform speed.

[0038] Comparative Example 4 The difference from Example 2 is that an unmodified rotor spinning machine is used for the cotton feed plate and cotton passage.

[0039] The yarns produced in the above examples and comparative examples were tested for evenness using a Uster UT6 fully automatic yarn evenness tester at a speed of 400 m / min; the breaking strength and coefficient of variation of strength were tested using a Nantong Hongda HD021NH electronic chemical fiber filament tensile tester at a tensile speed of 500 mm / min.

[0040] The test results are shown in Table 1.

[0041] Table 1 Test Results

[0042] As shown in Table 1, under the same yarn count, the test data of Examples 2 and 3 are similar to those of Comparative Example 1, and they already have the style of linen. However, the coarse and fine details of Comparative Examples 2, 3, and 4 are not prominent, and the cotton knots are not obvious, which is not consistent with the style of linen.

Claims

1. A method for producing rotor-spun linen-like yarn, characterized in that: The method first adjusts the carding process to prepare fiber slivers with controllable neps. The fiber slivers with controllable neps are combined with combed slivers for two passes and then used as raw material for rotor spinning. The slivers are precisely controlled by a servo motor dynamic slub control system and then enter the rotor spinning machine for drafting and twisting through a modified feed board and cotton passage (7) to obtain linen-like yarn.

2. The method for producing rotor-spun linen-like yarn according to claim 1, characterized in that: The preparation of the fiber sliver containing controllable neps includes: by modifying the structure and designing the process of the carding machine, a fiber sliver containing controllable neps is prepared, wherein the number of neps is controlled to be above 1500 per meter.

3. The method for producing rotor-spun linen-like yarn according to claim 2, characterized in that: The fiber sliver containing controllable neps is combined with the combed sliver at a mass ratio of 1:4 to 1:5, and then processed by a four-up-three-down drafting device, with the draft ratio controlled within the range of 5 to 7.2 times.

4. The method for producing rotor-spun linen-like yarn according to claim 1, characterized in that: The quantitative range for cooked strips is 18-30g / 5m.

5. The method for producing rotor-spun linen-like yarn according to claim 1, characterized in that: Structural modifications and process design for the carding machine: a) Increase the distance between the licker-in roller and the cylinder to 0.20-0.23mm; b) Reduce the speed of the licker-in roller and set the rotation speed to 780-852rpm; c) Invert the movable cover plate and increase the distance between the cylinder and the movable cover plate to 0.51, 0.41, 0.41, and 0.76mm at the four interval points; d) Invert the fixed cover plate.

6. The method for producing rotor-spun linen-like yarn according to claim 1, characterized in that: The dynamic slub control system prioritizes the establishment of a database containing 512 sets of slub characteristic parameters. Through servo motor linkage, it precisely controls the step feeding of cotton sliver, achieving adjustable spinning with a base yarn length of 100-500mm, a slub length of 80-100mm, and a slub thickness increment of 50%-200%.

7. The method for producing rotor-spun linen-like yarn according to claim 1, characterized in that: The modification of the cotton feeding plate is as follows: a groove (2) is set in the cotton feeding plate to penetrate its working surface (1). The height of the groove (2) is 8mm, and the deepest part is 1.2mm away from the working surface (1) of the cotton feeding plate.

8. The method for producing rotor-spun linen-like yarn according to claim 7, characterized in that: A blocking block (4) with a diameter of 1 mm and an extension length of 1.5 mm is set inside the cotton passage (7).

9. The method for producing rotor-spun linen-like yarn according to claim 1, characterized in that: The process parameters for composite spinning are as follows: rotor speed is 55,000-60,000 rpm, carding roller speed is set to 6,000-8,000 rpm, twist coefficient is controlled at 450-500, and the humidity of the spinning environment is maintained at 55%-65%.

10. A rotor-spun linen-like yarn, characterized in that: It is produced by the method for producing rotor-spun linen-like yarn as described in any one of claims 1-9.

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