Lyocell fiber vortex spun yarn and method of making same

Abstract

The application discloses lyocell fiber vortex spinning yarn and a preparation method thereof. The lyocell fiber vortex spinning yarn is prepared by adopting lyocell fiber as raw material through the processes of opening and cleaning, carding, drawing, vortex spinning, inspection, warehousing, doubling, doubling and twisting, and warehousing. Compared with the prior art, the lyocell fiber vortex spinning yarn prepared by the application has good fiber purity and neatness, high production efficiency, good quality, and good thermal cycle stability, antibacterial performance and washing resistance.

Description

Technical Field

[0001] This invention relates to the field of novel spinning technology, and in particular to a vortex-spun lyocell fiber yarn and its preparation method. Background Technology

[0002] Lyocell fiber is a man-made fiber with many unique properties and application advantages. Lyocell fiber can be blended with other fibers to create a variety of functional textiles. For example, blending it with cotton can improve the softness and moisture absorption of textiles, while blending it with polyester can increase the durability and quick-drying properties. Lyocell fiber has excellent moisture absorption and breathability, making it suitable for manufacturing products such as medical dressings, sanitary napkins, and diapers. It also has a soft, smooth touch, making it skin-friendly. The softness and luster of lyocell fiber make it ideal for producing high-quality clothing and home textiles. It can be used to make shirts, skirts, bedding, curtains, etc. Lyocell fiber has excellent moisture-wicking properties, making it suitable for making sportswear, outdoor clothing, and functional sports socks. Lyocell fiber is a biodegradable fiber, which can be used to make disposable items, eco-friendly bags, and biodegradable implant materials in the biomedical field. Lyocell fiber can also be used in industrial applications such as filter materials, electronic products, and films.

[0003] Despite its many advantages, lyocell fiber also has some drawbacks. Lyocell fiber has relatively low strength when wet and is more prone to tearing or deformation compared to other fibers. This limits its use in certain applications. Lyocell fiber is susceptible to wrinkling, especially in humid environments. This can lead to garment deformation or poor appearance, requiring special care and treatment. Lyocell fiber has high hygroscopicity, easily absorbing moisture and remaining damp. This can result in a damp feeling in humid environments and a longer drying time. Compared to some synthetic fibers, lyocell fiber has lower durability and is easily abraded and damaged after heat / cooling cycles. Special attention needs to be paid to fiber care and usage to extend its lifespan. Due to its high hygroscopicity, lyocell fiber is prone to bacterial growth during application, affecting its quality. Therefore, developing a lyocell fiber with excellent antibacterial properties and high durability is crucial.

[0004] Chinese authorized invention patent CN113897782B discloses a method for preparing an antibacterial fabric, comprising modifying polyester fiber with dimethyloctadecyl[3-trimethoxysilane]ammonium chloride, then spinning short-fiber warp yarns by vortex spinning; modifying lyocell fiber with diethyl maleate bis[octadecyldimethyl]ammonium chloride, then spinning the modified polyester fiber with the modified polyester fiber by vortex spinning to obtain weft yarns; the warp and weft yarns are then spun to obtain an antibacterial fabric; the resulting fabric is effective against Staphylococcus aureus and Escherichia coli. The antibacterial rates of *Candida albicans* and *Candida albicans* before and after washing were 96.1–98.5%, 95.4–98.4%, 94.8–95.9%, 93.2–96.6%, 92.2–95.8%, and 91.8–92.8%, respectively; the warp and weft breaking strengths were 911–993 N and 803–855 N, respectively; the warp and weft tearing strengths were 52–60 N and 33–39 N, respectively; the dimensional change rate after washing was -0.06–0.13%; and the pilling rate was grade 5. However, the antibacterial fabric prepared by this invention is not washable, has poor antibacterial performance, and low durability under thermal cycling. Summary of the Invention

[0005] In view of the shortcomings of existing vortex-spun lyocell fiber yarns, such as poor antibacterial properties, poor water resistance, and easy damage during thermal cycling, the technical problem to be solved by the present invention is to provide a vortex-spun lyocell fiber yarn with good antibacterial properties, water resistance, and good thermal cycling performance, as well as a method for preparing the same.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A method for preparing vortex-spun lyocell fiber yarn is as follows:

[0008] Step 1, Opening and cleaning: The Lyocell fibers are processed using an opening machine;

[0009] Step 2, Carding: The Lyocell fibers that have undergone opening and cleaning are fed into the carding machine for carding;

[0010] Step 3, drawing: The carded Lyocell fibers are fed into the drawing frame to obtain the sliver;

[0011] Step 4, Vortex spinning: The sliver is vortex spun;

[0012] Step 5, Inspection: This includes inspection of neps, semi-finished and finished slivers, yarn evenness, thickness and thinness, and neps. Sampling inspections are conducted on semi-finished or finished products from each production process, including periodic and real-time sampling. Through data inspection and analysis, it is determined whether the semi-finished or finished products produced in each process meet the quality control requirements.

[0013] Step 6, Warehousing: Once the quality control requirements are met, the item is put into storage.

[0014] Step 7, Joining: Join the yarns that have been received into the warehouse;

[0015] Step 8: Twist twice; Twist the doubling yarn twice;

[0016] Step 9, Warehousing: Once the quality control requirements are met, the item is put into storage.

[0017] Preferably, the speed of the carding beater of the opening machine is between 350 and 400 rpm, the distance between the feeding roller and the beater is between 5 and 8 mm, and the speed of the overall beater of the lap forming machine is between 400 and 800 rpm, so as to avoid damaging the fibers due to excessive speed; the lap weight is controlled at 300 to 350 g / m, and the length is controlled at 20 to 35 m.

[0018] Preferably, the carding process is configured as follows: cylinder speed 350-400 rpm, flats speed 70-80 m / min, licker-in speed 700-1000 rpm, doffer speed 20-40 rpm, cylinder-flats five-point spacing 6-8 mm, 5-7 mm, 5-7 mm, 5-7 mm, 6-8 mm, cylinder-licker-in spacing 6-8 mm, cylinder-doffer spacing 4-6 mm, and basis weight 14-18 g / 5 m.

[0019] Preferably, the drawing process is configured as follows: the machine speed is controlled at 200-240 m / min, the roller spacing is 8-12×15-17 mm, the roller center distance is 48-52×50-52 mm, and during the pre-drawing of the slivers, 2-8 slivers are drawn together, with a draft ratio of 4-8 in the front zone and 1.1-1.5 in the rear zone; for the second drawing, 2-8 slivers are drawn together, with a draft ratio of 4-8 in the front zone and 1.1-1.5 in the rear zone; for the third drawing, 2-8 slivers are drawn together, with a draft ratio of 4-8 in the front zone and 1.1-1.5 in the rear zone.

[0020] Preferably, the vortex spinning process is configured as follows: spinning speed 200-400 m / min, total draft ratio 150-200 times, main zone draft ratio 30-40 times, middle zone draft ratio 2-4 times, back zone draft ratio 1-2 times, roller center distance 42-46 mm × 41-44 mm × 43-46 mm, and spindle diameter 1-1.2 mm.

[0021] Preferably, the plying involves selecting 2 to 4 yarns and combining them into one, and the plying speed is 100 to 500 rpm. Preferably, the twisting speed is 6000 to 7000 rpm, the twist is between 200 and 300 T / M, and the twist direction is "S".

[0022] The preparation method of the lyocell fiber is as follows, in parts by weight:

[0023] S1. 8-12 parts of chitin were stirred at 40-80 rpm for 1-3 hours in 80-120 parts of 10-20 wt% NaOH aqueous solution, then frozen at -15 to -20℃ for 5-20 hours, and then thawed to obtain a thawed solution. 400-500 parts of ice were added to the thawed solution and stirred at 150-200 rpm for 1-3 hours. Then, under the conditions of 60-90℃ and 50-100 rpm, 20-40 parts of 1-3 wt% 2-chloroethylamine hydrochloride aqueous solution and 20-40 parts of water were added and stirred at 40-80 rpm for 15-20 hours. The mixture was dialyzed with water for 1-5 days until the dialyzed molecular weight was 700-1000 Da. The mixture was then freeze-dried to obtain modified chitin.

[0024] S2. Wet 8-12 parts of the modified chitin prepared in step S1 with 25-35 parts of water, then add it to 400-600 parts of 80-88wt% phosphoric acid aqueous solution and stir at 500-1000 rpm for 1-3 hours to obtain solution A. Pour solution A into 4000-6000 parts of water, centrifuge at 8000-12000 rpm for 3-8 minutes to remove phosphoric acid, and perform high-pressure homogenization 3-8 times at 500-1000 bar to obtain the pretreated material.

[0025] S3. Mix 0.5-2 parts of 2-acetamidofluorene and 2-4 parts of n-dodecane at 100-300 rpm for 20-40 min, then add 80-120 parts of the pretreated material prepared in step S2, and homogenize at 18000-22000 rpm for 3-8 min to obtain an emulsion. Heat the emulsion and maintain it at 70-90℃ for 1-5 h. During the heating process, add 3-8 wt% NaOH aqueous solution dropwise to adjust the pH to 10-11.5, then add 8-12 parts of 8-12 wt% ethylenediamine aqueous solution, filter to collect the solid, and air dry at room temperature for 10-30 h to obtain the functional agent.

[0026] S4. Mix 1300-1800 parts of N-methylmorpholine-N-oxide monohydrate, 80-120 parts of cellulose pulp, 5-10 parts of isoamyl gallate, and 13-18 parts of the functional agent prepared in step S3 under vacuum at 80-95°C and 100-300 rpm for 2-5 hours. Produce lyocell fiber using a dry-wet spinning process.

[0027] Preferably, the process parameters for the wet-dry spinning method are as follows: air gap of 2.5-3.5 cm, side blowing temperature of room temperature, coagulation bath temperature of 18-22°C; pump supply of 10-15 g / min; spinning speed of 80-120 m / min; spinneret orifice diameter of 0.12-0.18 mm, and number of orifices of 80-120.

[0028] In the described method for preparing lyocell fibers, the roles of each substance are as follows:

[0029] Chitin: Chitin is a natural polymer derived from the shells of crustaceans. Its main function is to provide raw materials for the preparation of modified chitin.

[0030] NaOH aqueous solution: A 15 wt% NaOH aqueous solution is used to suspend and dissolve chitin, and to aid in dispersion and dissolution during stirring.

[0031] 2-Chloroethylamine hydrochloride aqueous solution: reacts with chitin to introduce specific amino groups, thereby improving the antibacterial activity of chitin.

[0032] Phosphoric acid aqueous solution: used to dissolve chitin, forming a stable emulsion.

[0033] 2-Acetamidofluorene: Used to mix with n-dodecane, add to the pretreated material prepared in step S2, and then undergo high-speed homogenization. During this process, 2-acetamidofluorene may react with certain components in the pretreated material to form functional agents with specific functions. Therefore, 2-acetamidofluorene may play multiple roles in this preparation method, acting as a solvent, catalyst, and modifier.

[0034] Ethylenediamine aqueous solution: used to adjust the pH value in step S3.

[0035] N-Methylmorpholine-N-oxide monohydrate: A solvent used in the dry and wet spinning process of lyocell fibers. The aqueous solution of N-methylmorpholine-N-oxide monohydrate is weakly alkaline. The NO bond in the molecule is highly polar, and the electron cloud density on the oxygen atom is very high, readily forming hydrogen bonds with water molecules and the hydroxyl groups in cellulose molecules, exhibiting strong hydrophilicity. The strong polarity of its NO bond (easily forming hydrogen bonds) and the weak binding force of the NO bond make N-methylmorpholine-N-oxide monohydrate widely used in organic synthesis and as a solvent for cellulose.

[0036] Cellulose pulp: N-methylmorpholine-N-oxide monohydrate, a major raw material in the wet and dry spinning process, is used to prepare lyocell fibers.

[0037] Isoamyl gallate: N-methylmorpholine-N-oxide monohydrate, an antioxidant with good antioxidant properties and chemical stability. During the spinning process, it may play a role in preventing fiber oxidation and improving fiber durability. Furthermore, isoamyl gallate can also reduce the decomposition of N-methylmorpholine-N-oxide monohydrate.

[0038] Functional agent: obtained from the reaction in step S3, which has the special function of modifying the surface properties of cellulose pulp.

[0039] The above describes the roles of various substances in the preparation of lyocell fibers. They interact through different chemical reactions and physical processes to ultimately obtain lyocell fibers.

[0040] The main reasons for the deterioration of mechanical properties and antibacterial performance of lyocell fibers after heating / cooling cycles in existing technologies are related to their material properties and structure. Reduced crystallinity: During the preparation of lyocell fibers, processes such as spinning and drawing are used to form a crystalline structure, improving the fiber's strength and stability. However, during heating / cooling cycles, the crystallinity of the fiber may decrease, leading to a decline in its mechanical properties. Heating / cooling cycles may cause the breakage or relaxation of the lyocell fiber molecular chains, resulting in a decrease in fiber strength and durability. Detergents used during washing may interact with the lyocell fibers, causing functional changes or damage to the fiber surface, thereby reducing antibacterial performance. Heating / cooling cycles cause the fibers to be repeatedly subjected to temperature changes and mechanical stress, which may lead to fatigue and damage to the internal structure of the fiber, thus affecting its mechanical and antibacterial properties. It should be noted that the performance of lyocell fibers is affected by multiple factors, including the fiber preparation process, material selection, and post-treatment. To address these issues, this invention improves the fiber performance by modifying methods to enhance the performance stability of lyocell fibers during heating / cooling cycles and washing processes.

[0041] The introduction of 2-chloroethylamine hydrochloric acid aqueous solution and the alkalization process of chitin endowed modified chitin with better antibacterial activity, attributed to its complex membrane structure. In the presence of modified chitin, the introduction of positive charges and amino groups during the alkalization process leads to the interaction between modified chitin and bacterial cell membranes, resulting in damage to the bacterial cell membranes and leakage of intracellular proteins, thereby producing an antibacterial effect.

[0042] The surface morphology of the vortex-spun lyocell fiber yarn remained unchanged after repeated heating / cooling cycles. Typically, additives reduce fiber strength, possibly due to a decrease in the degree of cellulose polymerization. The vortex-spun lyocell fiber yarn prepared according to this invention did not have a significant negative impact on tensile properties.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1) This invention prepares vortex-spun lyocell fiber yarn by subjecting the lyocell fiber to a series of physical and chemical treatments, thereby improving the fiber's quality and performance. The fiber processing speed is controlled using an opener and a lap-forming machine to avoid fiber damage. The carding process effectively removes impurities and short fibers, improving fiber purity and uniformity.

[0045] 2) This invention employs precise process control. During the preparation process, multiple process parameters are controlled, such as cylinder speed, cover plate speed, licker-in roller speed, and draw ratio, to ensure that the quality and performance of the fiber are precisely controlled.

[0046] 3) The present invention uses vortex spinning technology to achieve high-speed spinning, with a spinning speed of up to 300m / min, and a high draft ratio, which can produce a large amount of lyocell fiber yarn in a short time.

[0047] 4) During the preparation process, this invention allows for strict quality control of the fibers through random sampling and real-time monitoring of both semi-finished and finished products. This helps ensure that the produced fibers meet quality requirements and provides a means for data verification and analysis.

[0048] 5) This invention uses modified chitin and functional agents in the preparation method of lyocell fiber through functional modification. Through chemical reaction and treatment, the fiber is endowed with specific functional properties, such as enhanced thermal cycling strength, antibacterial properties and water resistance. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the modified chitin synthesis process in the preparation method of lyocell fiber described in Example 1. Detailed Implementation

[0050] Main source of materials:

[0051] Chitosan: Xi'an Miaoguo Biotechnology Co., Ltd., Model: MG-JKS.

[0052] Cellulose pulp: Sigma-Aldrich (Shanghai) Trading Co., Ltd., item number: NISTRM8496.

[0053] Example 1

[0054] A method for preparing vortex-spun lyocell fiber yarn:

[0055] Step 1, Opening and cleaning: The lyocell fiber is processed using an opening machine. The speed of the carding and beating hand of the opening machine is between 380 rpm, the distance between the feed roller and the beating hand is between 7 mm, and the speed of the overall beating hand of the lap forming machine is between 600 rpm to avoid damaging the fiber due to excessive speed. The lap weight is controlled at 320 g / m and the length is controlled at 28 m.

[0056] Step 2, Carding: The lyocell fibers that have undergone opening and cleaning are fed into the carding machine. The carding process is configured as follows: cylinder speed 380 rpm, flats speed 80 m / min, licker-in speed 850 rpm, doffer speed 30 rpm, cylinder-flats five-point spacing 7 mm, 6 mm, 6 mm, 6 mm, 7 mm, cylinder-licker-in spacing 7 mm, cylinder-doffer spacing 5 mm, and basis weight 20 g / 5 m.

[0057] Step 3, Drawing: The carded Lyocell fibers are fed into the drawing frame. The drawing process configuration is as follows: machine speed controlled at 220 m / min, roller spacing 10×16 mm, roller center distance 50×51 mm. During the pre-drawing of the sliver, 6 slivers are drawn together, with a front draft ratio of 5.8 and a back draft ratio of 1.25; for the second drawing, 6 slivers are drawn together, with a front draft ratio of 4 and a back draft ratio of 1.24; for the third drawing... Six slivers are combined, with a front zone draft ratio of 5 and a back zone draft ratio of 1.26 to obtain a finished sliver; Step 4, Vortex spinning: The finished sliver is vortex spun. The vortex spinning process configuration is as follows: spinning speed 300m / min, total draft ratio 171 times, main zone draft ratio 38 times, middle zone draft ratio 3 times, back zone draft ratio 1.5 times, roller center distance 44.5mm×43mm×45mm, spindle diameter 1.1mm;

[0058] Step 5, Inspection: This includes inspection of neps, semi-finished and finished slivers, yarn evenness, thickness and thinness, and neps. Sampling inspections are conducted on semi-finished or finished products from each production process, including periodic and real-time sampling. Through data inspection and analysis, it is determined whether the semi-finished or finished products produced in each process meet the quality control requirements.

[0059] Step 6, Warehousing: Once the quality control requirements are met, the item is put into storage.

[0060] Step 7, Twining: Twin the yarns that have been put into storage, selecting two yarns and merging them into one, at a speed of 300 rpm; Step 8, Twisting: Twisting is done at a speed of 6500 rpm and a twist of 250 T / M, with the twist direction being "S".

[0061] Step 9, Warehousing: Once the quality control requirements are met, the item is put into storage.

[0062] The method for preparing the lyocell fiber is as follows:

[0063] S1. 10g of chitin was stirred at 60rpm for 2h in 100g of 15wt% NaOH aqueous solution, then frozen at -18℃ for 12h, and then thawed to obtain the thawed solution. 450g of ice was added to the thawed solution and stirred at 180rpm for 2h. Then, under the conditions of stirring at 80℃ and 80rpm, 30g of 2wt% 2-chloroethylamine hydrochloride aqueous solution and 30g of water were added and stirred at 60rpm for 18h. The mixture was dialyzed with water for 3 days, and the dialyzed molecular weight was 800Da. The mixture was then freeze-dried to obtain modified chitin.

[0064] S2. Wet 10g of the modified chitin prepared in step S1 with 30g of water, then add it to 500g of 85wt% phosphoric acid aqueous solution and stir at 800rpm for 2h to obtain solution A. Pour solution A into 5000g of water, centrifuge at 10000rpm for 5min to remove phosphoric acid, and perform high-pressure homogenization 5 times at 800bar to obtain the pretreated material.

[0065] S3. Mix 1g of 2-acetamidofluorene and 3g of n-dodecane at 200rpm for 30min, then add 100g of the pretreated material prepared in step S2, and homogenize at 20000rpm for 5min to obtain an emulsion. Heat the emulsion and maintain it at 80℃ for 3h. During the heating process, add 5wt% NaOH aqueous solution to adjust the pH to 11, then add 10g of 10wt% ethylenediamine aqueous solution, filter to collect the solid, and air dry at room temperature for 24h to obtain the functional agent.

[0066] S4. Mix 1500g of N-methylmorpholine-N-oxide monohydrate, 100g of cellulose pulp, 9g of isoamyl gallate, and 15g of the functional agent prepared in step S3 under vacuum at 200rpm for 4h at 90℃. Produce lyocell fiber using a dry-wet spinning process. The dry-wet spinning process parameters are as follows: air gap is 3cm, side blowing temperature is room temperature, coagulation bath temperature is 20℃; pump feed rate is 12g / min; spinning speed is 100m / min; spinneret orifice diameter is 0.145mm, and the number of orifices is 100. Lyocell fiber is obtained.

[0067] Comparative Example 1

[0068] The preparation method of vortex-spun lyocell fiber yarn is basically the same as that in Example 1, except that the preparation method of the lyocell fiber is different.

[0069] The method for preparing the lyocell fiber is as follows:

[0070] S1. Wet 10g of chitin with 30g of water, then add it to 500g of 85wt% phosphoric acid aqueous solution and stir at 800rpm for 2h to obtain solution A. Pour solution A into 5000g of water, centrifuge at 10000rpm for 5min to remove phosphoric acid, and perform high-pressure homogenization 5 times at 800bar to obtain pretreated material.

[0071] S2. Mix 1g of 2-acetamidofluorene and 3g of n-dodecane at 200rpm for 30min, then add 100g of the pretreated material prepared in step S1, and homogenize at 20000rpm for 5min to obtain an emulsion. Heat the emulsion and maintain it at 80℃ for 3h. During the heating process, add 5wt% NaOH aqueous solution dropwise to adjust the pH to 11, then add 10g of 10wt% ethylenediamine aqueous solution, filter to collect the solid, and air dry at room temperature for 24h to obtain the functional agent.

[0072] S3. Mix 1500g of N-methylmorpholine-N-oxide monohydrate, 100g of cellulose pulp, 9g of isoamyl gallate, and 15g of the functional agent prepared in step S2 under vacuum at 200rpm for 4h at 90℃. Produce lyocell fiber using a wet-dry spinning process. The wet-dry spinning process parameters are as follows: air gap is 3cm, side blowing temperature is room temperature, coagulation bath temperature is 20℃; pump feed rate is 12g / min; spinning speed is 100m / min; spinneret orifice diameter is 0.145mm, and the number of orifices is 100. Lyocell fiber is obtained.

[0073] Comparative Example 2

[0074] The preparation method of vortex-spun lyocell fiber yarn is basically the same as that in Example 1, except that the preparation method of the lyocell fiber is different.

[0075] The method for preparing the lyocell fiber is as follows:

[0076] S1. 10g of chitin was stirred at 60rpm for 2h in 100g of 15wt% NaOH aqueous solution, then frozen at -18℃ for 12h, and then thawed to obtain a thaw solution. 450g of ice was added to the thaw solution and stirred at 180rpm for 2h. Then, under the conditions of stirring at 80℃ and 80rpm, 30g of 2wt% 2-chloroethylamine hydrochloride aqueous solution and 30g of water were added and stirred at 60rpm for 18h. The mixture was dialyzed with water for 3 days, and the dialyzed molecular weight was 800Da. The mixture was then freeze-dried to obtain modified chitin.

[0077] S2. Wet 10g of the modified chitin prepared in step S1 with 30g of water, then add it to 500g of 85wt% phosphoric acid aqueous solution and stir at 800rpm for 2h to obtain solution A. Pour solution A into 5000g of water, centrifuge at 10000rpm for 5min to remove phosphoric acid, and perform high-pressure homogenization 5 times at 800bar to obtain the pretreated material.

[0078] S3. Mix 1500g of N-methylmorpholine-N-oxide monohydrate, 100g of cellulose pulp, 9g of isoamyl gallate, and 15g of the pretreated material prepared in step S2 under vacuum at 200rpm for 4h at 90℃. Produce lyocell fiber using a wet-dry spinning process. The wet-dry spinning process parameters are as follows: air gap is 3cm, side blowing temperature is room temperature, coagulation bath temperature is 20℃; pump feed rate is 12g / min; spinning speed is 100m / min; spinneret orifice diameter is 0.145mm, and the number of orifices is 100. Lyocell fiber is obtained.

[0079] Comparative Example 3

[0080] The preparation method of vortex-spun lyocell fiber yarn is basically the same as that in Example 1, except that the preparation method of the lyocell fiber is different.

[0081] The method for preparing the lyocell fiber is as follows:

[0082] S1. 10g of chitin was stirred at 60rpm for 2h in 100g of 15wt% NaOH aqueous solution, then frozen at -18℃ for 12h, and then thawed to obtain a thaw solution. 450g of ice was added to the thaw solution and stirred at 180rpm for 2h. Then, under the conditions of stirring at 80℃ and 80rpm, 30g of 2wt% 2-chloroethylamine hydrochloride aqueous solution and 30g of water were added and stirred at 60rpm for 18h. The mixture was dialyzed with water for 3 days, and the dialyzed molecular weight was 800Da. The mixture was then freeze-dried to obtain modified chitin.

[0083] S2. Wet 10g of the modified chitin prepared in step S1 with 30g of water, then add it to 500g of 85wt% phosphoric acid aqueous solution and stir at 800rpm for 2h to obtain solution A. Pour solution A into 5000g of water, centrifuge at 10000rpm for 5min to remove phosphoric acid, and perform high-pressure homogenization 5 times at 800bar to obtain the pretreated material.

[0084] S3. Mix 1g of 2-acetamidofluorene and 3g of n-dodecane at 200rpm for 30min, then add 100g of the pretreated material prepared in step S2, and homogenize at 20000rpm for 5min to obtain an emulsion. Heat the emulsion and maintain it at 80℃ for 3h. During the heating process, add 5wt% NaOH aqueous solution to adjust the pH to 11, then add 10g of 10wt% ethylenediamine aqueous solution, filter to collect the solid, and air dry at room temperature for 24h to obtain the functional agent.

[0085] S4. Mix 1500g of N-methylmorpholine-N-oxide monohydrate, 100g of cellulose pulp and 15g of the functional agent prepared in step S3 under vacuum at 90℃ and 200rpm for 4h. Produce lyocell fiber using a dry-wet spinning process. The dry-wet spinning process parameters are as follows: air gap is 3cm, side blowing temperature is room temperature, coagulation bath temperature is 20℃; pump supply is 12g / min; spinning speed is 100m / min; spinneret orifice diameter is 0.145mm and the number of orifices is 100. Lyocell fiber is obtained.

[0086] Comparative Example 4

[0087] The preparation method of vortex-spun lyocell fiber yarn is basically the same as that in Example 1, except that the preparation method of the lyocell fiber is different.

[0088] The method for preparing the lyocell fiber is as follows:

[0089] 1500g of N-methylmorpholine-N-oxide monohydrate and 100g of cellulose pulp were mixed under vacuum at 90℃ and 200rpm for 4h. Lyocell fiber was produced using a wet-dry spinning process. The process parameters for wet-dry spinning were as follows: air gap of 3cm, side blowing temperature of room temperature, coagulation bath temperature of 20℃, pump flow rate of 12g / min, spinning speed of 100m / min, spinneret orifice diameter of 0.145mm, and number of orifices of 100. Lyocell fiber was obtained.

[0090] Test Example 1

[0091] Washing and antibacterial performance test

[0092] The lyocell fiber vortex-spun yarns prepared in the embodiments and comparative examples of the present invention were woven into a plain weave using conventional weaving technology, with a warp density of 80 ends / 10cm and a weft density of 100 ends / 10cm.

[0093] The antibacterial properties of fabrics prepared from the vortex-spun lyocell fiber yarns of the embodiments and comparative examples of this invention against Gram-negative Escherichia coli (ATCC11229) and Gram-positive Staphylococcus aureus (ATCC6538) were tested according to GB / T20944.3-2008 "Evaluation of antimicrobial properties of textiles - Part 3: Oscillation method". The fabrics were washed according to standard washing procedures, and the antimicrobial properties were tested after one wash. Each group was tested five times, and the average value was taken. The test results are shown in Table 1.

[0094] Table 1 Results of Washing and Antibacterial Performance Tests

[0095]

[0096] Test Example 2

[0097] Thermal cycling capability test

[0098] Using an electronic single yarn strength tester (YG061, Laizhou Electronic Instruments Co., Ltd.), and following GB / T3916-2013 "Determination of breaking strength and elongation at break of single yarn in packaged yarns of this invention" as the test standard, the strength of the lyocell fiber vortex-spun yarns prepared in the embodiments and comparative examples of this invention was tested. The test interval of the strength tester was set to 500 mm, the tensile speed to 500 mm / min, the pre-tension to 4 cN, the number of yarns tested to be 50, and the linear density of the yarn to be 18.2 tex. The average value of the breaking strength of the blended yarns was taken. The yarns were baked at 60℃ for 5 min, then cooled at 10℃ for 5 min, and this cycle was repeated 100 times. The breaking strength of the yarns was then tested using the same method. The test results are shown in Table 2.

[0099] Table 2 Results of Thermal Cycling Capacity Test

[0100]

[0101] The lyocell fiber vortex-spun yarn prepared in Example 1 of this invention has high antibacterial properties and thermal cycling ability. The possible reason is that Example 1 of this invention uses lyocell fiber as raw material and prepares the lyocell fiber vortex-spun yarn through the processes of opening and cleaning cotton, carding, drawing, vortex spinning, inspection, warehousing, doubling, twisting, and warehousing. The preparation method of the lyocell fiber is as follows: Chitosan is stirred in NaOH aqueous solution, then frozen, then thawed to obtain a thawed solution. Ice is added to the thawed solution and stirred. Then, under high temperature stirring conditions, 2-chloroethylamine hydrochloride aqueous solution and water are added, stirred, dialyzed with water, and freeze-dried to obtain modified chitosan. The modified chitosan is moistened with water and then added to phosphoric acid aqueous solution and stirred to obtain solution A. Solution A is poured into water, centrifuged, phosphoric acid is removed, and homogenized under high pressure to obtain a pretreated material. Isophorone diisocyanate and n-octadecane are stirred and mixed, then added to the pretreated material aqueous solution, homogenized to obtain an emulsion. The emulsion is heated and maintained. During the heating process, NaOH aqueous solution is added dropwise, then ethylenediamine aqueous solution is added. The solid is collected by filtration and air-dried at room temperature to obtain a functional agent. N-methylmorpholine-N-oxide monohydrate, pulp, isoamyl gallate and functional agent are mixed at high temperature and vacuum, and lyocell fiber is produced by wet-dry spinning process.

[0102] By comparing Example 1 and Comparative Example 1, some differences exist in the preparation process of lyocell fibers between the two methods. The lyocell fibers in Example 1 underwent modified chitin treatment during preparation, which may result in better wash-resistant and antibacterial properties on the fiber surface. Modified chitin possesses better natural antibacterial properties; the introduction of 2-chloroethylamine hydrochloric acid aqueous solution and the alkalization process of chitin endowed the modified chitin with better antibacterial activity. This is attributed to its complex membrane structure, which may enhance the antibacterial properties of the fiber by inhibiting bacterial growth. Therefore, compared to Comparative Example 1, the lyocell fibers prepared in Example 1 may have better wash-resistant and antibacterial properties.

[0103] By comparing Example 1 and Comparative Example 2, the lyocell fiber prepared using functional agents in Example 1 may exhibit better antibacterial properties during washing and better mechanical properties after thermal cycling compared to the lyocell fiber prepared directly using the pretreatment material in Comparative Example 2. The functional agents, through the addition of 2-acetamidofluorene, n-dodecane, and an aqueous solution of ethylenediamine, are compounded with the pretreatment material to inhibit bacterial growth and reproduction, maintaining fiber cleanliness and hygienic properties during washing. The addition of functional agents may also improve the internal structure and interactions of the fiber, enhancing its mechanical properties. Specifically, the components in the functional agents may interact with fiber molecules, for example, through cross-linking or reinforcing bond formation, thereby increasing fiber strength and stability.

[0104] The preparation methods of Example 1 and Comparative Example 3 differ. The addition of isoamyl gallate in Example 1 may possess antibacterial properties, inhibiting bacterial growth and reproduction. Lyocell fibers with added isoamyl gallate may release this substance during washing, giving the fibers a strong antibacterial effect. Isoamyl gallate may form a durable antibacterial layer on the fiber surface, allowing the lyocell fibers to maintain their antibacterial properties after multiple washes, thus extending their service life. Isoamyl gallate may also enhance the internal structure and interactions of the fiber. It can interact with fiber molecules, increasing fiber strength and stability, thereby improving the mechanical properties of lyocell fibers after thermal cycling.

Claims

1. A method for preparing vortex-spun lyocell fiber yarn, characterized in that, The preparation method is as follows: Step 1, Opening and cleaning: The Lyocell fibers are processed using an opening machine; Step 2, Carding: The Lyocell fibers that have undergone opening and cleaning are fed into the carding machine for carding; Step 3, drawing: The carded Lyocell fibers are fed into the drawing frame to obtain the sliver; Step 4, Vortex spinning: The sliver is vortex spun; Step 5, Inspection: This includes inspection of neps, semi-finished and finished slivers, yarn evenness, thickness and thinness, and neps. Sampling inspections are conducted on semi-finished or finished products from each production process, including periodic and real-time sampling. Through data inspection and analysis, it is determined whether the semi-finished or finished products produced in each process meet the quality control requirements. Step 6, Warehousing: Once the quality control requirements are met, the item is put into storage. Step 7, Joining: Join the yarns that have been received into the warehouse; Step 8: Twist twice; Twist the doubling yarn twice; Step 9, Warehousing: Once the quality control requirements are met, the item is put into storage. The preparation method of the lyocell fiber is as follows, in parts by weight: S1. 8-12 parts of chitin were stirred at 40-80 rpm for 1-3 hours in 80-120 parts of 10-20 wt% NaOH aqueous solution, then frozen at -15 to -20℃ for 5-20 hours, and then thawed to obtain a thawed solution. 400-500 parts of ice were added to the thawed solution and stirred at 150-200 rpm for 1-3 hours. Then, under the conditions of 60-90℃ and 50-100 rpm, 20-40 parts of 1-3 wt% 2-chloroethylamine hydrochloride aqueous solution and 20-40 parts of water were added and stirred at 40-80 rpm for 15-20 hours. The mixture was dialyzed with water for 1-5 days until the dialyzed molecular weight was 700-1000 Da. The mixture was then freeze-dried to obtain modified chitin. S2. Wet 8-12 parts of the modified chitin prepared in step S1 with 25-35 parts of water, then add it to 400-600 parts of 80-88wt% phosphoric acid aqueous solution and stir at 500-1000 rpm for 1-3 hours to obtain solution A. Pour solution A into 4000-6000 parts of water, centrifuge at 8000-12000 rpm for 3-8 minutes to remove phosphoric acid, and perform high-pressure homogenization 3-8 times at 500-1000 bar to obtain the pretreated material. S3. Mix 0.5-2 parts of 2-acetamidofluorene and 2-4 parts of n-dodecane at 100-300 rpm for 20-40 min, then add 80-120 parts of the pretreated material prepared in step S2, and homogenize at 18000-22000 rpm for 3-8 min to obtain an emulsion. Heat the emulsion and maintain it at 70-90℃ for 1-5 h. During the heating process, add 3-8 wt% NaOH aqueous solution dropwise to adjust the pH to 10-11.5, then add 8-12 parts of 8-12 wt% ethylenediamine aqueous solution, filter to collect the solid, and air dry at room temperature for 10-30 h to obtain the functional agent. S4. Mix 1300-1800 parts of N-methylmorpholine-N-oxide monohydrate, 80-120 parts of cellulose pulp, 5-10 parts of isoamyl gallate, and 13-18 parts of the functional agent prepared in step S3 under vacuum at 80-95°C and 100-300 rpm for 2-5 hours. Produce lyocell fiber using a dry-wet spinning process.

2. The method for preparing vortex-spun lyocell fiber yarn as described in claim 1, characterized in that, The speed of the carding beater of the opening machine is between 350 and 400 rpm, the distance between the feed roller and the beater is between 5 and 8 mm, and the speed of the overall beater of the lap forming machine is between 400 and 800 rpm to avoid damaging the fibers due to excessive speed; the lap weight is controlled at 300 to 350 g / m, and the length is controlled at 20 to 35 m.

3. The method for preparing vortex-spun lyocell fiber yarn as described in claim 1, characterized in that, The carding process is configured as follows: cylinder speed 350-400 rpm, flats speed 70-80 m / min, licker-in speed 700-1000 rpm, doffer speed 20-40 rpm, cylinder-flats five-point spacing 6-8 mm, 5-7 mm, 5-7 mm, 5-7 mm, 6-8 mm, cylinder-licker-in spacing 6-8 mm, cylinder-doffer spacing 4-6 mm, and basis weight 14-18 g / 5 m.

4. The method for preparing vortex-spun lyocell fiber yarn as described in claim 1, characterized in that, The drawing process is configured as follows: the machine speed is controlled at 200-240 m / min, the roller spacing is 8-12 × 15-17 mm, the roller center distance is 48-52 × 50-52 mm, and during the pre-drawing of the slivers, 2-8 slivers are drawn together, with a draft ratio of 4-8 in the front zone and 1.1-1.5 in the rear zone; during the second drawing, 2-8 slivers are drawn together, with a draft ratio of 4-8 in the front zone and 1.1-1.5 in the rear zone; during the third drawing, 2-8 slivers are drawn together, with a draft ratio of 4-8 in the front zone and 1.1-1.5 in the rear zone.

5. The method for preparing vortex-spun lyocell fiber yarn as described in claim 1, characterized in that, The vortex spinning process is configured as follows: spinning speed 200-400 m / min, total draft ratio 150-200 times, main zone draft ratio 30-40 times, middle zone draft ratio 2-4 times, back zone draft ratio 1-2 times, roller center distance 42-46 mm × 41-44 mm × 43-46 mm, and spindle diameter 1-1.2 mm.

6. The method for preparing vortex-spun lyocell fiber yarn as described in claim 1, characterized in that, The plucking process involves selecting 2 to 4 yarns and combining them into one, with a plucking speed of 100 to 500 rpm.

7. The method for preparing vortex-spun lyocell fiber yarn as described in claim 1, characterized in that, The twisting speed is 6000-7000 rpm, the twist is 200-300 T / M, and the twist direction is "S".

8. The method for preparing vortex-spun lyocell fiber yarn as described in claim 1, characterized in that, The process parameters for the dry-wet spinning method are as follows: air gap is 2.5-3.5 cm, side blowing temperature is room temperature, and coagulation bath temperature is 18-22℃. The pump supply is 10-15 g / min; the spinning speed is 80-120 m / min; the spinneret orifice diameter is 0.12-0.18 mm, and the number of orifices is 80-120.

9. A vortex-spun yarn of lyocell fiber, characterized in that, It is prepared by the method described in any one of claims 1 to 8.

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