Vortex spinning lyocell coarse yarn and preparation process

Abstract

The invention relates to a vortex spinning lyocell coarse yarn and a preparation process thereof, and belongs to the technical field of vortex spinning, the vortex spinning lyocell coarse yarn is prepared by the following steps: pretreating lyocell fibers by using deionized water and a nonionic surfactant to remove impurities such as surface spinning oil and dust, and then treating the pretreated lyocell fibers in a low-temperature and low-pressure plasma environment to obtain the vortex spinning lyocell coarse yarn. The gas in the plasma reaction chamber is oxygen, active groups such as carboxyl and hydroxyl are introduced to the surfaces of the pretreated lyocell fibers, the surface roughness is increased while the mechanical property of the pretreated lyocell fibers is guaranteed, and the mechanical friction force between the fibers is enhanced; the modified lyocell fibers and the polyester staple fibers form hydrogen bonds and covalent bonds with amino groups in dopamine hydrochloride molecules in the forming process of the polydopamine coating, the stability of the coating is improved, in addition, the cohesive force between the modified lyocell fibers and the polyester staple fibers is further increased due to the viscosity of the polydopamine coating, and the tensile strength of the polyester staple fibers is improved. The mechanical strength and durability of the vortex spinning lyocell coarse yarn are synergistically improved.

Description

Technical Field

[0001] This invention belongs to the field of vortex spinning technology and relates to a coarse-count vortex-spun Lyocell yarn and its preparation process. Background Technology

[0002] From the perspective of yarn count requirements, coarse yarns are widely used in products such as sweatshirts, casual jackets, blankets, and decorative fabrics due to their high bulk, good warmth retention, and cost-effectiveness. Traditional lyocell yarn spinning primarily uses ring spinning. While ring spinning can produce yarns with a tight structure and less hairiness, it suffers from a long process flow (requiring multiple steps such as carding, drawing, roving, and spinning), low production efficiency, and high energy consumption, making it difficult to meet market demands. In contrast, vortex spinning uses a high-speed rotating airflow to create a vortex in the spinning cup, where the outer fibers wrap around the core fibers to form yarn. The entire process eliminates the need for traditional components such as spindles, rings, and travelers, simplifying the process to "carding-drawing-vortex spinning." This significantly improves production efficiency compared to ring spinning and reduces energy consumption, offering a significant cost and efficiency advantage in coarse yarn production.

[0003] Chinese invention patent application CN112877825B discloses a jet-jet vortex-spun multi-component antibacterial yarn and its preparation method. The antibacterial yarn, by weight percentage, comprises the following components: 18.5-21.5% combed short-staple cotton, 18.5-21.5% combed long-staple cotton, 14-16% fine denier polyester staple fiber, 28.5-31.5% antibacterial polyester staple fiber, and 13.5-16.5% lyocell fiber. The yarn produced has high strength, is crisp yet soft, and has antibacterial properties. When this yarn is used as the weft yarn, the fabric produced has crispness, antibacterial properties, anti-pilling properties, and quick-drying properties. It has been used to make medical hand sanitizers, and the quality meets the requirements.

[0004] The surface of the lyocell fiber used in the above scheme is relatively smooth. If it is used directly for blending, the cohesion between it and antibacterial polyester staple fiber and fine denier polyester staple fiber is insufficient, resulting in weak interfacial bonding between lyocell fiber and antibacterial polyester. This makes it easy to form local fiber density differences during the stretching process, which not only makes it easy to break but also easy to cause fiber separation. Summary of the Invention

[0005] The purpose of this invention is to provide a coarse-count lyocell yarn spun by vortex spinning and its preparation process. The process involves plasma treatment and coating treatment on the surface of lyocell fibers, followed by mixing with polyester staple fibers and then vortex spinning to obtain coarse-count yarn, thereby improving the cohesion and mechanical properties between fibers.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A process for preparing vortex-spun Lyocell coarse-count yarn includes the following steps:

[0008] Step 1: Plasma treatment is performed on the pretreated lyocell fibers to obtain plasma-treated lyocell fibers. Then, dopamine hydrochloride molecules are polymerized on the surface of the plasma-treated lyocell fibers to form a coating, thus obtaining modified lyocell fibers.

[0009] Step 2: Polyester staple fiber and modified lyocell fiber are mixed and impurities are removed. The mixture is then processed through carding, drawing, and air-jet vortex spinning to obtain vortex-spun lyocell coarse yarn.

[0010] Furthermore, the specific preparation process of modified lyocell fiber is as follows:

[0011] Dopamine hydrochloride and deionized water were added to a reaction vessel and stirred to dissolve. Tris buffer was added and the pH was adjusted to 8-9 to obtain a mixture. Plasma-treated Lyocell fibers were then immersed in the mixture and stirred at 25-30℃ for 8-10 hours to obtain modified Lyocell fibers.

[0012] Furthermore, the ratio of dopamine hydrochloride, deionized water, Tris buffer, and plasma-treated lyocell fiber is 2.0-3.0g: 1-1.5L: 1.2-1.6g: 80-120g.

[0013] Furthermore, the specific preparation process of plasma-treated Lyocell fibers is as follows:

[0014] Pretreated Lyocell fibers are wound onto a paper tube and mounted on a winding wheel in a plasma reaction chamber. After evacuation and stabilization of the pressure, oxygen is introduced for plasma treatment. The fibers are then removed, washed, and dried to obtain plasma-treated Lyocell fibers.

[0015] Furthermore, the vacuum level of the vacuum pump is 20-25 Pa.

[0016] Furthermore, the plasma treatment power is 300-400W, and the time is 30-60s.

[0017] Furthermore, the specific preparation process of pretreated lyocell fibers is as follows:

[0018] Lyocell fiber, nonionic surfactant and deionized water at 60-65℃ are added to a reaction vessel, soaked for 10-20 minutes, removed, washed and dried to obtain pretreated lyocell fiber.

[0019] Furthermore, the ratio of polyester staple fiber to modified lyocell fiber is 60-70:30-40.

[0020] Furthermore, the spinning speed in the jet vortex spinning process is 480-520 r / min, the total draft ratio is 230-280, the main draft ratio is 38-40, the back draft ratio is 2.95-3.05, the feed ratio is 0.96-0.98, the crimp ratio is 1.00-1.02, the matching nozzle air pressure is 0.57-0.60 MPa, and the humidity during spinning is 58-62%.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention first pretreats lyocell fibers with deionized water and nonionic surfactants to remove surface spinning oils and dust, and then treats the pretreated lyocell fibers in a low-temperature, low-pressure plasma environment. The gas in the plasma reaction chamber is oxygen, which introduces active groups such as carboxyl and hydroxyl groups onto the surface of the pretreated lyocell fibers. This increases surface roughness while maintaining mechanical properties, enhances the mechanical friction between fibers, and forms hydrogen bonds and covalent bonds with amino groups in the dopamine hydrochloride molecules during the formation of the polydopamine coating, improving the stability of the coating. In addition, the viscosity of the polydopamine coating further increases the cohesion between the modified lyocell fibers and polyester staple fibers, synergistically improving the mechanical strength and durability of the eddy-spun lyocell coarse-count yarn.

[0023] 2. In a low-temperature, low-pressure plasma environment, this invention etches the surface of pretreated lyocell fibers through high-energy particle bombardment, increasing the surface roughness of the pretreated lyocell fibers. Simultaneously, high-energy ion bombardment induces oxidation reactions of surface free radicals (during the plasma reaction in an oxygen atmosphere), introducing carboxyl groups onto the surface of the pretreated lyocell fibers. The carboxyl groups react with the amino groups of dopamine hydrochloride molecules, which not only accelerates the formation of the coating but also improves its adhesion. Then, using polyester staple fiber as the yarn skeleton and modified lyocell fiber as the wrapping layer, the invention ensures the strength of the eddy-spun lyocell coarse-count yarn while imparting skin-friendliness and improving the mixing uniformity between fibers. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0025] Example 1: This example provides a coarse-count vortex-spun Lyocell yarn, prepared through the following steps:

[0026] S1: Add 150g of lyocell fiber (length 38-51mm, fineness 1.2-1.5D, purchased from Shandong Runjin Textile), 0.35g of nonionic surfactant Tween-80 and 1150mL of deionized water at 62℃ to the reaction vessel, soak for 15min, take out the lyocell fiber, wash it 4 times with deionized water, dry it at 82℃ to remove surface impurities, and obtain pretreated lyocell fiber.

[0027] S2: 150g of pretreated lyocell fiber is wound onto a paper tube and installed on the winding wheel of the plasma reaction chamber. The plasma reaction chamber is evacuated to 22Pa. After the pressure stabilizes, oxygen is introduced into the reaction chamber at a constant rate to treat the pretreated lyocell fiber with plasma at a power of 350W for 45s. Under low-temperature and low-pressure plasma conditions, high-energy particle bombardment causes etching on the surface of the pretreated lyocell fiber, increasing its surface roughness. Simultaneously, high-energy ion bombardment induces oxidation of surface free radicals, introducing active groups such as -C=O, -COOH, and -OH onto the surface of the pretreated lyocell fiber. After the reaction, the fiber is removed, repeatedly washed, and dried at 62℃ to obtain plasma-treated lyocell fiber.

[0028] The low-temperature, low-pressure plasma treatment equipment, model GY-QX03, was purchased from AOP Plasma Technology Co., Ltd.

[0029] S3: Add 2.5g of dopamine hydrochloride and 1.2L of deionized water to the reactor, stir to dissolve, add 1.4g of Tris buffer, adjust the pH to 8, and obtain a mixture. Immerse 100g of plasma-treated lyocell fiber into the mixture and stir at 27℃ for 9h to ensure uniform reaction. Dopamine hydrochloride molecules spontaneously polymerize on the surface of plasma-treated lyocell fiber, eventually forming a uniform polydopamine coating, and obtaining modified lyocell fiber.

[0030] S4: 65% polyester staple fiber and 35% modified lyocell fiber are mixed, opened, and impurities are removed by an opening and cleaning machine to produce and process cotton laps that meet the required weight and length. The laps are then carded by a TC10 carding machine, followed by a drawing process. Finally, the yarn is spun using an MVSNo.870EX air-jet vortex spinning machine. The spinning speed of the air-jet vortex spinning process is 500 r / min, the total draft ratio is 255, the main draft ratio is 39, the back draft ratio is 3.0, the feed ratio is 0.97, the crimp ratio is 1.01, the matching nozzle air pressure is 0.58 MPa, and the humidity during spinning is 60%, resulting in vortex-spun lyocell coarse yarn.

[0031] Example 2: This example provides a coarse-count vortex-spun Lyocell yarn, prepared through the following steps:

[0032] S1: Add 100g of lyocell fiber (length 38-51mm, fineness 1.2-1.5D, purchased from Shandong Runjin Textile), 0.1g of nonionic surfactant Tween-80, and 800mL of deionized water at 60℃ to the reactor, soak for 10min, remove the lyocell fiber, wash it 3 times with deionized water, dry it at 80℃ to remove surface impurities, and obtain pretreated lyocell fiber.

[0033] S2: 100g of pretreated lyocell fiber is wound onto a paper tube and installed on the winding wheel of the plasma reaction chamber. The plasma reaction chamber is evacuated to 20Pa. After the pressure stabilizes, oxygen is introduced into the reaction chamber at a constant rate to treat the pretreated lyocell fiber with plasma at a power of 300W for 30s. Under low-temperature and low-pressure plasma conditions, high-energy particle bombardment causes etching on the surface of the pretreated lyocell fiber, increasing its surface roughness. Simultaneously, high-energy ion bombardment induces oxidation of surface free radicals, introducing active groups such as -C=O, -COOH, and -OH onto the surface of the pretreated lyocell fiber. After the reaction, the fiber is removed, repeatedly washed, and dried at 60℃ to obtain plasma-treated lyocell fiber.

[0034] The low-temperature, low-pressure plasma treatment equipment, model GY-QX03, was purchased from AOP Plasma Technology Co., Ltd.

[0035] S3: Add 2.0g of dopamine hydrochloride and 1.0L of deionized water to the reactor, stir to dissolve, add 1.2g of Tris buffer, adjust the pH to 8.0, and obtain a mixture. Immerse 80g of plasma-treated lyocell fiber into the mixture and stir at 25℃ for 8h to ensure uniform reaction. Dopamine hydrochloride molecules spontaneously polymerize on the surface of plasma-treated lyocell fiber, eventually forming a uniform polydopamine coating, and obtaining modified lyocell fiber.

[0036] S4: 60% polyester staple fiber and 40% modified lyocell fiber are mixed, opened, and impurities are removed by an opening and cleaning machine to produce and process cotton laps that meet the required weight and length. The laps are then carded by a TC5-1s carding machine, followed by a drawing process. Finally, the yarn is spun using an MVSNo.870EX air-jet vortex spinning machine. The spinning speed of the air-jet vortex spinning process is 480 r / min, the total draft ratio is 230, the main draft ratio is 38, the back draft ratio is 2.95, the feed ratio is 0.96, the crimp ratio is 1.00, the matching nozzle air pressure is 0.57 MPa, and the humidity during spinning is 58%, resulting in vortex-spun lyocell coarse yarn.

[0037] Example 3: This example provides a coarse-count vortex-spun Lyocell yarn, prepared through the following steps:

[0038] S1: Add 200g of lyocell fiber (length 38-51mm, fineness 1.2-1.5D, purchased from Shandong Runjin Textile), 0.6g of nonionic surfactant Tween-80 and 1500mL of deionized water at 65℃ to the reactor, soak for 20min, take out the lyocell fiber, wash it 5 times with deionized water, dry it at 85℃ to remove surface impurities, and obtain pretreated lyocell fiber.

[0039] S2: 200g of pretreated lyocell fiber is wound onto a paper tube and installed on the winding wheel of the plasma reaction chamber. The plasma reaction chamber is evacuated to 25Pa. After the pressure stabilizes, oxygen is introduced into the reaction chamber at a constant rate to treat the pretreated lyocell fiber with plasma at a power of 400W for 60s. Under low-temperature and low-pressure plasma conditions, high-energy particle bombardment causes etching on the surface of the pretreated lyocell fiber, increasing its surface roughness. Simultaneously, high-energy ion bombardment induces oxidation of surface free radicals, introducing active groups such as -C=O, -COOH, and -OH onto the surface of the pretreated lyocell fiber. After the reaction, the fiber is removed, repeatedly washed, and dried at 65℃ to obtain plasma-treated lyocell fiber.

[0040] The low-temperature, low-pressure plasma treatment equipment, model GY-QX03, was purchased from AOP Plasma Technology Co., Ltd.

[0041] S3: Add 3.0g of dopamine hydrochloride and 1.5L of deionized water to the reactor, stir to dissolve, add 1.6g of Tris buffer, adjust the pH to 9.0, and obtain a mixture. Immerse 120g of plasma-treated lyocell fiber into the mixture and stir at 30℃ for 10h to ensure uniform reaction. Dopamine hydrochloride molecules spontaneously polymerize on the surface of plasma-treated lyocell fiber, eventually forming a uniform polydopamine coating, and obtaining modified lyocell fiber.

[0042] S4: 70% polyester staple fiber and 30% modified lyocell fiber are mixed, opened, and impurities are removed by an opening and cleaning machine to produce and process cotton laps that meet the required weight and length. The laps are then carded by a TC5-1s carding machine, followed by a drawing process. Finally, the laps are spun using an MVSNo.870EX air-jet vortex spinning machine. The spinning speed of the air-jet vortex spinning process is 520 r / min, the total draft ratio is 280, the main draft ratio is 40, the back draft ratio is 3.05, the feed ratio is 0.98, the crimp ratio is 1.02, the nozzle air pressure is 0.60 MPa, and the humidity during spinning is 62%, resulting in vortex-spun lyocell coarse yarn.

[0043] Example 4: This example provides a coarse-count vortex-spun Lyocell yarn. The difference from Example 1 is that the nonionic surfactant Tween-80 is not added in step S1.

[0044] Example 5: This example provides a coarse-count vortex-spun Lyocell yarn. The difference from Example 1 is that step S1 is omitted, and Lyocell fiber is used instead of pretreated Lyocell fiber in step S2.

[0045] Comparative Example 1: This comparative example provides a coarse-count vortex-spun Lyocell yarn, which differs from Example 1 in that Lyocell fiber is used instead of modified Lyocell fiber in step S4.

[0046] Comparative Example 2: This comparative example provides a coarse-count vortex-spun Lyocell yarn, which differs from Example 1 in that the modified Lyocell fiber is replaced with the plasma-treated Lyocell fiber prepared in step S2 in step S4.

[0047] Comparative Example 3: This comparative example provides a coarse-count vortex-spun Lyocell yarn. The difference from Example 1 is that in step S3, the pretreated Lyocell fiber prepared in step S1 is used instead of the plasma-treated Lyocell fiber.

[0048] The performance of the vortex-spun Lyocell coarse-count yarns prepared in Examples 1-5 and Comparative Examples 1-3 was tested:

[0049] Yarn tensile properties test: Refer to GB / T 3916—2013 "Determination of breaking strength and elongation at break of single yarn in packaged yarn of textiles", use YG068C fully automatic single yarn tensile tester (Suzhou Changfeng Textile Machinery & Electrical Technology Co., Ltd.) for testing. The sampling tensile speed is 500m / min, the spacing is 500mm, the pre-tension is 0.5cN / tex, and each yarn package is tested 50 times and the average value is taken.

[0050] Yarn evenness test: Refer to GB / T 3292.1—2008 Textiles - Test method for yarn evenness - Part 1: Capacitance method. Use USTER®TESTER 5 electronic evenness tester (USTER AG, Switzerland) to test the yarn evenness rate. The test speed is 100m / min, each test is 500m, and three measurements are taken and the average value is taken.

[0051] Table 1 Performance Test Overview

[0052]

[0053] As shown in Table 1, the breaking strength and elongation at break of Examples 1-5 are greater than those of Comparative Examples 1-3, while the strength unevenness is less than that of Comparative Examples 1-3. This may be because the surface roughness of the lyocell fibers treated by plasma increases, and the surface free radicals are induced to undergo oxidation during the plasma treatment process, introducing active groups such as carboxyl and hydroxyl groups. Then, the hydrochloric acid dopamine molecules spontaneously polymerize on the surface of the plasma-treated lyocell fibers, which makes the compatibility between the modified lyocell fibers and polyester staple fibers better and increases the mechanical strength of the eddy-spun lyocell coarse count yarn.

[0054] As shown in Table 1, the unevenness of yarn in Examples 1-5 is less than that in Comparative Examples 1-3, indicating that the thickness fluctuation of the eddy-spun Lyocell coarse yarn is smaller in the length direction. This may be because the cohesion between the modified Lyocell fiber and the polyester staple fiber is improved, making the fiber distribution more uniform and thus improving durability.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for preparing coarse-count vortex-spun Lyocell yarn, characterized in that, Includes the following steps: Step 1: Plasma treatment is performed on the pretreated lyocell fibers to obtain plasma-treated lyocell fibers. Then, dopamine hydrochloride molecules are polymerized on the surface of the plasma-treated lyocell fibers to form a coating, thereby obtaining modified lyocell fibers. Step 2: Polyester staple fiber and modified lyocell fiber are mixed and impurities are removed. The mixture is then processed through carding, drawing, and air-jet vortex spinning to obtain vortex-spun lyocell coarse yarn.

2. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 1, characterized in that, The specific preparation process of the modified lyocell fiber is as follows: Dopamine hydrochloride and deionized water were added to a reaction vessel and stirred to dissolve. Tris buffer was added and the pH was adjusted to 8-9 to obtain a mixture. Plasma-treated Lyocell fibers were then immersed in the mixture and stirred at 25-30℃ for 8-10 hours to obtain modified Lyocell fibers.

3. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 2, characterized in that, The ratio of dopamine hydrochloride, deionized water, Tris buffer, and plasma-treated lyocell fiber is 2.0-3.0g: 1-1.5L: 1.2-1.6g: 80-120g.

4. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 1, characterized in that, The specific preparation process of the plasma-treated Lyocell fiber described in step one is as follows: Pretreated Lyocell fibers are wound onto a paper tube and mounted on a winding wheel in a plasma reaction chamber. After evacuation and stabilization of the pressure, oxygen is introduced for plasma treatment. The fibers are then removed, washed, and dried to obtain plasma-treated Lyocell fibers.

5. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 4, characterized in that, The vacuum level of the vacuum pump is 20-25 Pa.

6. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 4, characterized in that, The plasma treatment power is 300-400W, and the time is 30-60s.

7. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 4, characterized in that, The specific preparation process of the pretreated lyocell fiber is as follows: Lyocell fiber, nonionic surfactant and deionized water at 60-65℃ are added to a reaction vessel, soaked for 10-20 minutes, removed, washed and dried to obtain pretreated lyocell fiber.

8. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 1, characterized in that, The ratio of polyester staple fiber to modified lyocell fiber is 60-70:30-40.

9. The process for preparing vortex-spun Lyocell coarse-count yarn according to claim 1, characterized in that, In step two, the spinning speed of the air-jet vortex spinning process is 480-520 r / min, the total draft ratio is 230-280, the main draft ratio is 38-40, the back draft ratio is 2.95-3.05, the feed ratio is 0.96-0.98, the crimp ratio is 1.00-1.02, the matching nozzle air pressure is 0.57-0.60 MPa, and the humidity during spinning is 58-62%.

10. A type of vortex-spun Lyocell coarse-count yarn, characterized in that, It is prepared by any one of the vortex spinning Lyocell coarse count yarn preparation processes according to any one of claims 1-9.

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