Method for preparing recycled wool yarn

Abstract

A method for preparing a recycled wool yarn, comprising: opening pretreated waste wool textiles, so as to obtain recycled wool fibers; mixing the recycled wool fibers with functional fibers, followed by carding and drawing, so as to prepare a roving; and performing fine spinning.

Description

Preparation method of recycled wool yarn

[0001] This invention claims priority to Chinese Patent Application No. 2025102777499, filed on March 10, 2025, entitled “Method for preparing recycled wool yarn”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of spinning technology, and more specifically, this invention relates to a method for preparing recycled wool yarn. Background Technology

[0003] Globally, a large amount of waste wool textiles, such as discarded sweaters and factory scraps, are generated every year, but most of them are incinerated or landfilled, with only 1% of waste wool being recycled and reused. Indiscriminate dumping pollutes soil and water bodies, while the toxic gases produced by incineration contribute to air pollution. Reusing waste wool to spin recycled wool yarn can alleviate my country's wool resource shortage, reduce waste pollution, and meet the market demand for sustainable and recycled products in the textile and apparel industry.

[0004] During the recycling and processing of waste wool textiles, the recycled wool fibers are inevitably damaged, resulting in shortened fiber length and poor spinnability. To address this issue, recycled wool fibers are typically blended with functional fibers to produce recycled yarn. However, most current methods utilize rotor spinning technology, producing recycled wool yarns that are primarily low-to-medium count yarns (generally below 20 Nm in count and greater than 50 tex in fineness), resulting in low added value. Furthermore, the content of recycled wool fibers during blending is low, mostly not exceeding 30%, further reducing its sustainable utilization value. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a method for preparing medium- and high-count recycled wool yarn, and the method can use a higher content of recycled wool fibers.

[0006] In a first aspect, the present invention provides a method for preparing recycled wool yarn, comprising the following steps:

[0007] (1) Open the pretreated waste wool textiles to obtain recycled wool fibers;

[0008] (2) The recycled wool fibers and functional fibers described in step (1) are mixed and combed to obtain spinning raw materials; the weight percentage of the recycled wool fibers in the spinning raw materials is 30% to 90%;

[0009] (3) After cleaning and combing the spinning raw material described in step (2), the spinning fiber strip is output in a fixed length mode;

[0010] (4) The spun fiber slivers are drawn together to a linear density of 2500 tex to 2800 tex;

[0011] (5) The spun fiber sliver obtained in step (4) is made into a sliver with a linear density of 200 tex to 300 tex and a sliver weight of 2.0 g·10 m. -1 ~3.0g·10m -1 After the roving is produced, it is then spun by ring spinning, low-torque spinning or compact spinning to obtain recycled wool yarn.

[0012] The process parameters for ring spinning include: spindle speed 8000 r·min. -1 ~15000r·min -1 Fine yarn twist 800 twists·m -1 ~1000 twists·m -1 The process parameters for the low-torque spinning include: spindle speed 8000 r·min. -1 ~15000r·min -1 700 twists·m -1 ~900 twists·m -1 The false twist speed ratio is 1.8 to 2.2.

[0013] Secondly, the present invention provides recycled wool yarn obtained by the above preparation method.

[0014] The method for preparing recycled wool yarn of the present invention involves opening waste wool textiles that have undergone pretreatment (including component sorting, color sorting, disinfection, pretreatment, and opening pretreatment) to obtain recycled wool fibers. These fibers are then mixed with functional fibers, combed, drawn, roving, and spun (using ring spinning, low-torque spinning, or compact spinning methods). By adjusting the process parameters of key steps such as combing, drawing, roving, and spinning, the present invention can utilize more than 30% recycled wool fibers (up to 90% when the recycled wool fibers have good performance) for spinning. The resulting recycled wool yarn has a low linear density (15tex-50tex), high count, excellent strength and elongation, low hairiness, good evenness, and high added value. This invention significantly improves the sustainable utilization value of waste wool textiles, provides a useful reference for the high-value reuse of waste wool textiles, and also helps meet the market demand for high-performance environmentally friendly textiles.

[0015] In addition, the method for preparing recycled wool yarn of the present invention does not involve water treatment processes, saves energy and reduces consumption, and does not use environmentally harmful chemicals, making it a green processing technology. Attached Figure Description

[0016] Figure 1 is a process flow diagram of preparing recycled wool yarn in Embodiment 1 of the present invention.

[0017] Figure 2 shows the tensile strength of different recycled wool yarns in Example 2 of the present invention; where a is ring spinning, b is rotor spinning, and c is low torque spinning.

[0018] Figure 3 shows the amount of wool fibers larger than 3mm in different recycled wool yarns in Example 2 of the present invention. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0021] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all materials and reagents used are commercially available.

[0022] In this invention, the term "waste wool textiles" refers to waste clothing and textiles containing different amounts of wool and cashmere, different blends, and different colors. "Disinfection" can be achieved using ultraviolet light or ozone disinfection; "disassembly" refers to removing zippers, accessories, cuffs, hems, etc., from the waste wool textiles, leaving the main body for recycling; "dust removal" refers to using a suction dust removal device to remove dust and impurities from the disassembled waste wool textiles; "composition sorting" refers to grading the waste wool textiles according to their wool content using conventional methods in the art; and "color sorting" refers to manual sorting or using a color recognition device to classify them by color.

[0023] In some embodiments of the present invention, a method for preparing recycled wool yarn is disclosed, comprising the following steps:

[0024] (1) Open the pretreated waste wool textiles to obtain recycled wool fibers;

[0025] (2) The recycled wool fibers and functional fibers described in step (1) are mixed and combed to obtain spinning raw materials; the weight percentage of the recycled wool fibers in the spinning raw materials is 30% to 90%;

[0026] (3) After cleaning and combing the spinning raw material described in step (2), the spinning fiber strip is output in a fixed length mode;

[0027] (4) The spun fiber slivers are drawn together to a linear density of 2500 tex to 2800 tex;

[0028] (5) The spun fiber sliver obtained in step (4) is made into a sliver with a linear density of 200 tex to 300 tex and a sliver weight of 2.0 g·10 m. -1 ~3.0g·10m -1 After roving, the yarn is then spun into fine yarn (using spinning methods such as ring spinning, low-torque spinning, or compact spinning) to obtain recycled wool yarn.

[0029] The process parameters for ring spinning include: spindle speed 8000 r·min. -1 ~15000r·min -1 800 twists·m -1 ~1000 twists·m -1 The process parameters for the low-torque spinning include: spindle speed 8000 r·min. -1 ~15000r·min -1 700 twists·m -1 ~900 twists·m -1 The false twist speed ratio is 1.8 to 2.2.

[0030] In some embodiments, the ring spinning process parameters also include: a draft ratio of 9 to 15 times and a yarn exit speed of 10 m / min. -1 ~20m·min -1 The process parameters for the low-torque spinning also include: a draft ratio of 9 to 15 times and a yarn exit speed of 10 m / min. -1 ~20m·min -1 .

[0031] In some embodiments, step (5) employs low-torque spinning to obtain recycled wool yarn; the process parameters for the low-torque spinning include: spindle speed 8000 r·min. -1 ~10000r·min -1 700 twists·m -1 ~800 twists·m -1 False twist speed ratio 1.9–2.1, draft ratio 9–15, yarn exit speed 10 m / min -1 ~20m·min -1 .

[0032] In some embodiments, the process parameters for the low-torque spinning include: spindle speed 8900 r·min. -1~9100r·min -1 Fine yarn twist 720 twist·m -1 ~730 twists·m -1 False twist speed ratio 1.9–2.1, draft ratio 14–15, yarn exit speed 13 m / min -1 ~14m·min -1 .

[0033] In some embodiments, the weight percentage of the recycled wool fibers in the spinning raw material is 40% to 60%.

[0034] In some embodiments, the weight percentage of the recycled wool fibers in the spinning raw material is 45% to 55%.

[0035] In some embodiments, the weight percentage of the recycled wool fibers in the spinning raw material is 48% to 52%.

[0036] In some embodiments, the functional fiber is an antibacterial fiber, an antistatic fiber, an antibacterial and deodorizing fiber, or a flame-retardant fiber.

[0037] In some embodiments, the functional fiber is an antibacterial fiber.

[0038] In some embodiments, the cleaning and combing in step (3) is carried out in a combined cleaning and combing machine, which includes a roller carding machine and a cap carding machine. The process parameters of the roller carding machine are: cylinder speed: 600r / min~700r / min; cylinder diameter: 380mm~1020mm; draw ratio: 25 times~35 times. The process parameters of the cap carding machine are: cylinder speed: 450r / min~550r / min; cylinder diameter: 600mm~1400mm; draw ratio: 30 times~40 times.

[0039] In some embodiments, the length of the fixed-length mode in step (3) is 40m to 60m, and the back zone draw ratio is 1.3 to 1.5 times.

[0040] In some embodiments, the drawing process in step (4) includes: drawing 3 to 6 spun yarn fibers described in step (3) for the first time, then outputting 3 to 6 spun yarn fibers in a fixed-length mode, and then drawing for the second time; repeating this step until the linear density of the drawn spun yarn fibers is 2500 tex to 2800 tex.

[0041] In some embodiments, the length of the fixed-length mode in step (4) is 40m to 60m, and the back zone draw ratio is 1.3 to 1.5 times.

[0042] In some embodiments, during the second drawing, the draft ratio is 3 to 5 times, and the back zone draft ratio is 1.1 to 1.3 times.

[0043] In some embodiments, the process parameters for loosening in step (1) include: loosening roller speed: 837±5r / min; loosening roller diameter: 356±5mm.

[0044] In some embodiments, before pre-treating the waste wool textiles in step (1), the steps of disinfecting, disassembling, dusting, sorting by composition, and sorting by color of the waste wool textiles are also included.

[0045] In some embodiments, the pretreatment of waste wool textiles in step (1) includes the following steps: uniformly spraying an oiling agent of 10% to 25% of the mass of the waste wool textiles onto the surface of the waste wool textiles, then sealing at a temperature of 0°C to 20°C, a moisture regain of 30% to 90%, for 20 to 30 hours; the oiling agent is deionized water, wool oiling agent, and antistatic agent in a mass ratio of 11 to 13: 0.8 to 1.2: 0.2 to 0.4. The specific operation method is described in CN 116556042 B.

[0046] In some embodiments, the functional fiber in step (1) is a pretreated functional fiber. The pretreatment includes the following steps: spraying 10% to 25% of the functional fiber mass of an antistatic agent evenly on the surface of the functional fiber, then maintaining a temperature of 0°C to 20°C, a moisture regain of 30% to 90%, and sealing for 20 to 30 hours.

[0047] In the following embodiments of the present invention, the antibacterial fiber used is a polyhydroxyalkanoate (PHA) blend fiber (trade name: Hesu). TM The fibers (average length 38 mm, average fineness 10.6 μm) are mainly made from a mixture of hydroxybutyric acid (HBA) and hydroxyvalerate (PHBV) copolyester / polylactic acid (PLA) in a certain proportion, and were purchased from Nanjing Hesu Times Co., Ltd. The waste wool textiles were provided by Shenzhen Jinrongda Knitting & Garment Co., Ltd., and are pre-consumer waste wool knitted fabrics. The yarn in this knitted fabric is 100% wool yarn with a fineness of 21 tex; the wool fiber length is 58 mm, with a length CV value of 25.3%, and the fiber fineness is 19.5 μm with a fineness CV value of 8.0%. After pretreatment and opening, the recycled wool fibers have a length of 28.3 mm, a length CV value of 27.5%, and a fineness of 18.75 μm with a fineness CV value of 11.6%.

[0048] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1: Method for preparing recycled wool yarn

[0050] This embodiment uses 40% recycled wool fiber + 60% antibacterial fiber, 50% recycled wool fiber + 50% antibacterial fiber, and 60% recycled wool fiber + 40% antibacterial fiber as spinning raw materials, and employs three different spinning methods—ring spinning, rotor spinning, and low-torque spinning—to produce nine types of recycled wool yarns, including the following steps (please refer to Figure 1):

[0051] 1. Pretreatment

[0052] After disinfection, disassembly, dust removal, component sorting, and color sorting of waste wool textiles, a pre-treatment of opening is carried out, namely: evenly spraying 20% ​​of the mass of waste wool textiles with an oil agent (deionized water: wool oil agent: antistatic agent = 12:1:0.3) on the surface of the waste wool textiles, and then sealing it for 24 hours at 20℃ and 41% humidity.

[0053] Spray an antistatic agent of 20% of the weight of the antibacterial fiber evenly on the surface of the antibacterial fiber, and seal it for 24 hours at 20°C and 41% humidity.

[0054] 2. Loosening

[0055] Pretreated waste wool textiles are fed into an opening machine (opening roller speed: 837 r / min; opening roller diameter: 356 mm) according to a weight percentage ratio to open and obtain recycled wool fibers.

[0056] 3. Mixing

[0057] Regenerated wool fibers and antibacterial fibers are mixed and combed to obtain spinning raw materials;

[0058] 4. Comb

[0059] The spinning raw material from step 3 is fed into a combined cleaning and carding machine (including one roller carding machine (coarse carding cloth), a fan, a cotton feeding box, and one cover carding machine (fine carding cloth)), and output in a fixed length mode (50m, sliver output speed 15m / min) to obtain a uniformly distributed sliver of spinning fibers.

[0060] The process parameters for the roller carding machine are as follows: cylinder speed: 680 r / min; cylinder diameter: 380 mm; draw ratio: 30 times; and the process parameters for the cover plate carding machine are as follows: cylinder speed: 500 r / min; cylinder diameter: 600 mm; draw ratio: 33 times.

[0061] 5. Combined strips

[0062] Four spun fiber slivers are first drawn together (4 times drafted, 1.4 times drafted in the back zone) in a fixed length mode (50m, output speed 15m / min). After outputting four fiber slivers, a second drawing is performed (4 times drafted, 1.2 times drafted in the back zone). The linear densities of the fiber slivers after drawing are 2700tex (40% recycled wool fiber + 60% antibacterial fiber), 2325tex (50% recycled wool fiber + 50% antibacterial fiber), and 2800tex (60% recycled wool fiber + 40% antibacterial fiber).

[0063] 6. Rotor spinning

[0064] The fiber sliver after step 5 is fed into a rotor spinning machine (TS-3 type) for yarn spinning (process parameters are shown in Table 1) to obtain recycled wool yarn. During this process, there will be a breakage phenomenon, which should be related to the fiber being too short.

[0065] Table 1 Rotor spinning process parameters

[0066] 7. Ring spinning and low-torque spinning

[0067] The fiber sliver after step 5 is fed into a roving frame (FA497 model, process parameters are shown in Table 2, and adjustments are made according to the characteristics of the raw material and the results of the spinnability test) to obtain roving (roving specifications are shown in Table 3). During this process, fiber breakage may occur, which should be related to the fiber being too short.

[0068] Table 2 Process parameters of roving frame

[0069] Table 3. Roving Specifications

[0070] Then the roving is installed on a ring spinning machine (ZJ1298 type, process parameters are shown in Table 4) for yarn spinning (spinning environment temperature is 17℃~23℃, humidity is above 75%RH) to obtain recycled wool yarn.

[0071] Table 4. Process parameters for ring spinning and low-torque spinning

[0072] Example 2: Performance determination of 9 types of recycled wool yarns from Example 1

[0073] 1. Yarn linear density

[0074] The yarn count, or linear density, was tested according to standard GB / T 4743-2009, "Determination of Linear Density of Yarn in Packages and Skeins," using a YG086D yarn length measuring instrument and a balance with a mass of 0.1%. Under specified standard atmospheric conditions, 100m of yarn was taken using the yarn length measuring instrument, and the yarn weight was recorded on the balance before calculating the linear density. The average value of three tests was taken for each sample.

[0075] The results of the yarn linear density test (spun yarn linear density of 25 tex) are shown in Table 5.

[0076] Table 5 Linear Density of Nine Types of Recycled Wool Yarns

[0077] After spinning, the actual linear density of nine types of recycled wool yarns was measured, and it was found that the linear density of low-torque spinning was significantly lower than that of rotor spinning and ring spinning.

[0078] 2. Yarn strength and elongation properties

[0079] The tensile and elongation properties of the yarn were determined according to standard GB / T 3916-2013 "Determination of breaking strength and elongation at break of single yarn in packaged yarn (CRE method)" and were tested on a universal tensile testing machine with a pre-tension of 0.5 cN / tex, a testing speed of 500 mm / min, and a clamping distance of 500 mm. The average value of 30 tests was taken for each sample.

[0080] The breaking strength and breaking elongation of the nine types of recycled wool yarns (with a set yarn density of 25 tex) are shown in Figure 2.

[0081] Overall, the breaking strength of low-torque spun and ring-spun yarns is significantly better than that of rotor-spun yarns, with low-torque spun yarns exhibiting the best breaking strength. This is likely because low-torque spinning increases the fiber transfer frequency across the yarn cross-section, enhancing fiber cohesion and thus increasing the strength of the recycled wool yarn. Compared to ring-spun and low-torque spun yarns, the breaking strength and breaking elongation of rotor-spun recycled yarns fluctuate significantly. The lower breaking strength and greater differences in strength and elongation among blends of different fibers in rotor-spun yarns are due to the weaker fiber cohesion and the presence of more hooked fibers.

[0082] For ring-spun recycled yarn, when the recycled wool fiber content is 50%, the yarn strength is the highest at 8.61 cN / tex, and the breaking elongation is 19.75%. However, when the recycled wool fiber content reaches 60%, the breaking strength decreases to 7.77 cN / tex, a decrease of approximately 9.7%, and the breaking elongation decreases to 15.60%, a decrease of approximately 21.0%. For rotor-spun recycled yarn, when the recycled wool fiber content is 50%, the breaking strength and breaking elongation are the highest, at 6.64 cN / tex and 18.19%, respectively. However, when the recycled wool fiber content is 40% and 60%, the breaking strength and breaking elongation are both nearly 30% lower than when the recycled wool fiber content is 50%. For low-torque spun recycled yarn, when the recycled wool fiber content is 40% and 50%, the yarn strength and elongation are basically the same, with a breaking strength of approximately 9.37 cN / tex and a breaking elongation of approximately 14.79%.

[0083] Therefore, low-torque spinning and ring spinning, especially low-torque spinning, are easier to achieve the spinning of high-performance recycled yarns than rotor spinning.

[0084] 3. Yarn fuzz

[0085] Excessive fuzz not only hinders production but also damages the appearance and usability of the yarn. Generally, fuzz lengths of 3mm and above are considered harmful and will affect weaving results.

[0086] The yarn hairiness test was conducted according to standard FZ / T 01086-2020 "Textile Yarn Hairiness Determination Method - Projection Counting Method". A YG173 A type yarn hairiness tester was used to measure the hairiness of recycled wool yarn under conditions of 20℃ and 65% relative humidity. The pre-tension was 0.25 cN / tex, the yarn segment length for hairiness testing was 10 m, the testing speed was 30 m / min, and the average value of 10 tests was taken for each sample.

[0087] The yarn hairiness test results of 9 types of recycled wool yarn are shown in Table 6 and Figure 3.

[0088] Table 6. Hairiness properties of nine types of recycled wool yarns

[0089] As shown in Table 6 and Figure 3, the wool hairiness (above 3mm) in the recycled wool yarn prepared by low-torque spinning is the lowest among the three spinning methods, significantly better than ring spinning and rotor spinning, which have the highest hairiness. Therefore, low-torque spinning and ring spinning, especially low-torque spinning, are more conducive to spinning medium-to-high count recycled yarns with less hairiness than rotor spinning.

[0090] 4. Yarn evenness

[0091] The yarn evenness was tested according to standard GB / T 3292.1-2008 "Textiles - Test Methods for Yarn Evenness - Part 1: Capacitance Method" using a YG139 BA yarn evenness testing machine. The main test indicators included CV, number of small spots, number of large spots, and neps. The test speed was 100 m / min, and a total of 400 m of yarn was tested in four units. The average value of three tests was taken for each sample.

[0092] The evenness of the yarns of the nine types of recycled wool yarns is shown in Table 7.

[0093] Table 7. Evenness of Nine Types of Recycled Wool Yarns

[0094] Overall, ring-spun recycled yarn exhibits the best yarn evenness, followed by low-torque spun recycled yarn, while rotor-spun recycled yarn shows the worst evenness. When the recycled wool fiber content is 40%, the recycled yarns spun by all three spinning methods contain significantly higher levels of thick places (+50%) and neps (+200%) than those spun with 50% and 60% recycled wool fiber content. This may be because the high proportion of antibacterial fibers (38mm) has a longer length than the recycled wool fibers (28mm), resulting in more thick places and neps. From the perspective of the coefficient of variation (CV) of yarn, the three types of blended yarns prepared by ring spinning showed little difference compared to the recycled wool blended yarns. The CV values ​​of recycled yarns prepared by rotor spinning showed more significant differences, with the recycled yarn having the highest CV value when the recycled wool fiber content was 40%, followed by 60%, and the lowest at 18.21% when it was 50%. The evenness CV values ​​of recycled yarns prepared by low-torque spinning also showed some differences, but the evenness CV value of the recycled yarn with the highest recycled wool fiber content of 60% was the lowest. This shows that low-torque spinning has certain advantages for spinning shorter recycled fiber yarns.

[0095] Because recycled wool fibers are inevitably damaged during the recycling process, resulting in shortened fiber length and reduced spinnability, this invention controls the recycled wool fiber content between 30% and 90% by adjusting the process parameters of key steps such as opening and mixing, carding, drawing, roving, and spinning. Utilizing ring spinning and low-torque spinning technologies, high-count recycled wool yarn is produced, improving its performance. The resulting recycled wool yarn exhibits high strength and elongation, low hairiness, and excellent evenness, demonstrating superior yarn properties. Specifically, a recycled wool fiber content of 50% and low-torque spinning yields the best overall performance recycled wool yarn. This invention provides a valuable reference for the high-value reuse of waste wool textiles and also helps meet market demand for high-performance, environmentally friendly textiles.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing recycled wool yarn, characterized in that, Includes the following steps: (1) Open the pretreated waste wool textiles to obtain recycled wool fibers; (2) The recycled wool fibers and functional fibers described in step (1) are mixed and combed to obtain spinning raw materials; the weight percentage of the recycled wool fibers in the spinning raw materials is 30% to 90%; (3) After cleaning and combing the spinning raw material described in step (2), the spinning fiber strip is output in a fixed length mode; (4) The spun fiber slivers are drawn together to a linear density of 2500 tex to 2800 tex; (5) The spun fiber sliver obtained in step (4) is made into a sliver with a linear density of 200 tex to 300 tex and a sliver weight of 2.0 g·10 m. -1 ~3.0g·10m -1 After the roving is spun, it is then spun into ring spinning or low-torque spinning to obtain recycled wool yarn. The process parameters for ring spinning include: spindle speed 8000 r·min. -1 ~15000r·min -1 Fine yarn twist 800 twists·m -1 ~1000 twists·m -1 The process parameters for the low-torque spinning include: spindle speed 8000 r·min. -1 ~15000r·min -1 700 twists·m -1 ~900 twists·m -1 The false twist speed ratio is 1.8 to 2.

2.

2. The method for preparing recycled wool yarn according to claim 1, characterized in that, The process parameters for ring spinning also include: a draft ratio of 9 to 15 times and a yarn exit speed of 10 m / min. -1 ~20m·min -1 The process parameters for the low-torque spinning also include: a draft ratio of 9 to 15 times and a yarn exit speed of 10 m / min. -1 ~20m·min -1 .

3. The method for preparing recycled wool yarn according to claim 2, characterized in that, Step (5) involves low-torque spinning to obtain recycled wool yarn; The process parameters for the low-torque spinning include: spindle speed 8000 r·min -1 ~10000r·min -1 700 twists·m -1 ~800 twists·m -1 False twist speed ratio 1.9–2.1, draft ratio 9–15, yarn exit speed 10 m / min -1 ~20m·min -1 .

4. The method for preparing recycled wool yarn according to claim 3, characterized in that, The process parameters for the low-torque spinning include: spindle speed 8900 r·min -1 ~9100r·min -1 Fine yarn twist 720 twist·m -1 ~730 twists·m -1 False twist speed ratio 1.9–2.1, draft ratio 14–15, yarn exit speed 13 m / min -1 ~14m·min -1 .

5. The method for preparing recycled wool yarn according to claim 1, characterized in that, The weight percentage of the recycled wool fiber in the spinning raw material is 40% to 60%; And / or, the functional fiber is an antibacterial fiber, an antistatic fiber, an antibacterial and deodorizing fiber, or a flame-retardant fiber.

6. The method for preparing recycled wool yarn according to claim 5, characterized in that, The weight percentage of the recycled wool fiber in the spinning raw material is 45% to 55%, and the functional fiber is an antibacterial fiber.

7. The method for preparing recycled wool yarn according to claim 1, characterized in that, The cleaning and combing described in step (3) is carried out in a combined cleaning and combing machine, which includes a roller carding machine and a cap carding machine. The process parameters of the roller carding machine are: cylinder speed: 600r / min~700r / min; cylinder diameter: 380mm~1020mm; draw ratio: 25 times~35 times. The process parameters of the cap carding machine are: cylinder speed: 450r / min~550r / min; cylinder diameter: 600mm~1400mm; draw ratio: 30 times~40 times. And / or, the length of the fixed-length mode described in step (3) is 40m to 60m, and the back zone stretching ratio is 1.3 to 1.5 times.

8. The method for preparing recycled wool yarn according to claim 1, characterized in that, The drawing process in step (4) includes: drawing 3 to 6 spun yarn fibers described in step (3) for the first time, then outputting 3 to 6 spun yarn fibers in a fixed-length mode, and then drawing for the second time; repeating this step until the linear density of the drawn spun yarn fibers is 2500 tex to 2800 tex.

9. The method for preparing recycled wool yarn according to claim 8, characterized in that, The length of the fixed-length pattern is 40m to 60m, and the back zone draft ratio is 1.3 to 1.5 times; during the second drawing, the draft ratio is 3 to 5 times, and the back zone draft ratio is 1.1 to 1.3 times.

10. The method for preparing recycled wool yarn according to any one of claims 1 to 9, characterized in that, The process parameters for opening in step (1) include: opening roller speed: 837±5 r / min; opening roller diameter: 356±5 mm; And / or, before pre-treating the waste wool textiles in step (1), the steps of disinfecting, disassembling, dusting, sorting by composition, and sorting by color of the waste wool textiles are also included.

11. The method for preparing recycled wool yarn according to any one of claims 1 to 9, characterized in that, The pretreatment of waste wool textiles in step (1) includes the following steps: uniformly spraying 10% to 25% of the mass of the waste wool textiles with an oil agent on the surface of the waste wool textiles, then sealing at a temperature of 0℃ to 20℃, a moisture regain of 30% to 90%, for 20 to 30 hours; the oil agent is deionized water, wool oil agent, and antistatic agent in a mass ratio of 11 to 13: 0.8 to 1.2: 0.2 to 0.

4.

12. The method for preparing recycled wool yarn according to any one of claims 1 to 9, characterized in that, The functional fiber mentioned in step (2) is a pretreated functional fiber. The pretreatment includes the following steps: spraying 10% to 25% of the functional fiber mass of antistatic agent evenly on the surface of the functional fiber, then maintaining a temperature of 0°C to 20°C, a moisture regain of 30% to 90%, and sealing for 20 to 30 hours.

13. The recycled wool yarn obtained by the preparation method according to claims 1-12.

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