Preparation method of regenerated protein lyocell fiber based on ionic liquid dissolution and recovery of wool and silk

Abstract

The application discloses a preparation method of a regenerated protein lyocell fiber based on ionic liquid dissolution and recovery of plush and silk fibroin, and comprises the following operation steps: S1, after waste plush or silk fibers are crushed, washed and bleached, the fibers are dissolved in a dissolving kettle by using a double-component composite ionic liquid solvent to obtain a protein ionic solution; S2, after the protein ionic solution is filtered, pre-crushed wood pulp and a thermoplastic polyurethane elastomer (TPU) are added and blended and stirred to form a uniform spinning dope; S3, the spinning dope is extruded through a circular spinneret and enters a coagulating bath to obtain a regenerated protein fiber; and S4, the regenerated protein fiber is subjected to secondary water washing, drafting, oiling, drying and cutting to obtain a regenerated protein lyocell fiber. The application prepares a double-component composite solvent by preparing a composite of N-methylmorpholine N-oxide bromide and 1-ethyl-3-methyl imidazole bromide salt, and applies the double-component composite solvent to dissolution of waste plush or silk fibers and preparation of a high-protein-content regenerated protein lyocell fiber.

Description

Technical Field

[0001] This invention relates to the technical field of protein fiber preparation, specifically a method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids. Background Technology

[0002] Currently, a large amount of wool and silk waste, such as substandard wool and short combed wool from wool sorting, coarse cashmere scraps from cashmere combing, and substandard silk scraps from silk reeling, is difficult to degrade using conventional biotechnology. Effective recycling of this waste is of great significance and value for promoting environmental protection and conserving ecological resources. However, in the field of dissolving, extracting, and regenerating natural wool and silk proteins, traditional acid / alkali / enzymatic methods for extracting keratin are inefficient, result in severe molecular chain degradation, and cause significant pollution.

[0003] Over the years, through continuous improvement, patent CN 119463217 B utilizes N-methylmorpholine N-oxide (NMMO) as a solvent to prepare regenerated cellulose Lyocell fibers with good performance, such as Tencel and Modal, forming a green and environmentally friendly technology for preparing regenerated cellulose. However, due to the difficulty in dissolving wool and silk protein materials with N-methylmorpholine N-oxide (NMMO) and the difficulty in solving fiber regeneration processes, the development of high-content wool and silk fibroin protein regenerated fibers has been slow; furthermore, this method only stays at the solution preparation stage and has not been further spun into fibers.

[0004] Another patent, CN 117431660 A, discloses a method for preparing functional keratin fibers from waste wool. This method uses waste wool resources (such as spinning scraps and old carpets) as raw materials, dissolves the fibers in ionic liquids (such as 1-butyl-3-methylimidazolium bromide or 1-butyl-3-methylimidazolium chloride), and adds functional auxiliaries (such as peony bark or graphene) or biodegradable materials (such as sodium alginate or PLA) to prepare functional keratin fibers through wet spinning. While this method simplifies the process, it suffers from problems such as slow dissolution rate, insufficient fiber strength, and solvent waste.

[0005] This application aims to develop a novel fiber dissolution and preparation system, and provides a method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin regenerated protein using ionic liquids. Summary of the Invention

[0006] This application provides a method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids. The method involves preparing a two-component composite solvent by combining N-methylmorpholine bromide N-oxide ([NMMO]+Br-) with 1-ethyl-3-methylimidazolium bromide ([EMIM]+Br-), and applying it to dissolve waste wool or silk fibers to prepare an ionic solution of wool and silk fibroin regenerated protein. Then, the regenerated protein is prepared by blending wool and silk fibroin regenerated protein with cellulose to form pulp, and by dry-jet wet spinning to finally obtain regenerated protein lyocell fibers.

[0007] This application provides a method for preparing regenerated protein lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids, comprising the following steps: S1, waste wool or silk fibers are crushed, washed, and bleached, and then dissolved in a dissolving kettle using a two-component composite ionic liquid solvent to obtain a regenerated protein ionic solution; S2, the protein ionic solution is filtered, and pre-crushed wood pulp and thermoplastic polyurethane elastomer (TPU) are added and stirred to form a uniform spinning solution; S3, the spinning solution is extruded through a circular spinneret and enters a coagulation bath to obtain regenerated protein fibers; S4, the regenerated protein fibers are subjected to two-stage washing, stretching, oiling, drying, and cutting to obtain lyocell fibers; in step S1, the two-component composite ionic liquid is prepared by compounding N-methylmorpholine bromide N-oxide and 1-ethyl-3-methylimidazolium bromide in a mass ratio.

[0008] By adopting the above technical solution, this application integrates the dissolution, blending, spinning, and post-treatment of waste fibers into one process. Furthermore, it utilizes a two-component composite ionic liquid solvent, overcoming the limitation of low dissolution efficiency with single solvents. Simultaneously, the process includes solvent recovery, achieving closed-loop production.

[0009] Preferably, in step S1, the mass ratio of the N-methylmorpholine bromide N-oxide to the 1-ethyl-3-methylimidazolium bromide is 80-98:20-2.

[0010] By adopting the above technical solution, a single [NMMO] + Br - Or [EMIM] + Br - Neither of these methods can dissolve the fibers. In this application, a synergistic effect is achieved through a specific ratio of composite solvents. Furthermore, the composite solvents have a mild dissolution temperature and a high boiling point, exhibiting high thermal stability and ensuring process safety.

[0011] Preferably, in step S1, the bleaching treatment uses an H2O2 or NaClO system.

[0012] By adopting the above technical solution, impurities are removed through oxidative bleaching rather than chemical degradation, thus avoiding molecular chain breakage.

[0013] Preferably, in step S1, the dissolution conditions in the dissolving vessel are a temperature of 80-90°C, a time of 1-2.5 h, and a solid-liquid ratio of 1:5-10.

[0014] Preferably, in step S2, the degree of polymerization of the wood pulp (DP) is ≥600, and the amount of thermoplastic polyurethane elastomer (TPU) added is 2-3 wt%.

[0015] Preferably, in step S3, the coagulation bath is an aqueous solution of 8-10 wt% N-methylmorpholine bromide N-oxide and 0-2 wt% 1-ethyl-3-methylimidazolium bromide.

[0016] Preferably, the temperature of the coagulation bath is 0-35°C.

[0017] By adopting the above technical solution, which typically uses a single solvent in traditional Lyocell fiber coagulation baths, this application achieves slow fiber solidification through a composite solvent and low-temperature control in the coagulation bath. Furthermore, the low-temperature coagulation bath slows down phase separation, resulting in improved fiber surface smoothness and a more uniform internal structure.

[0018] Preferably, step S3 further includes the recovery of the coagulation bath, specifically: by continuously draining the coagulation bath and adding water or solvent to keep the concentration of the coagulation bath constant, the coagulated liquid discharged from the coagulation bath contains various impurities; after the coagulated liquid is removed by means of flocculation, anion and cation exchange, a pure low-concentration solvent aqueous solution is obtained; the water in the low-concentration solvent aqueous solution is evaporated and recovered, concentrated to the concentration required by the process, and used again as a solvent for preparing the spinning solution.

[0019] By adopting the above technical solution, this application discloses a solvent recovery step for a coagulation bath, including dynamic equilibrium of concentration, flocculation, ion exchange, and vacuum distillation. This is an innovation in green closed-loop process, which reduces raw material costs and waste emissions.

[0020] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0021] 1. This application describes the preparation of N-methylmorpholine bromide N-oxide ([NMMO)). + Br - ) and 1-ethyl-3-methylimidazolium bromide ([EMIM]) + Br -A two-component composite solvent was formed and applied to dissolve waste wool or silk fibers to prepare a wool and silk fibroin regenerated protein ionic solution. Then, the wool and silk fibroin regenerated protein was blended with cellulose to prepare pulp, and dry-jet wet spinning was used to form the final high-protein content regenerated protein lyocell fiber.

[0022] 2. In this application, the specific ratio of N-methylmorpholine N-oxide bromide to 1-ethyl-3-methylimidazolium bromide creates a synergistic effect in the composite solvent. The composite solvent has a mild dissolution temperature and a high boiling point, exhibiting high thermal stability and ensuring process safety.

[0023] 3. This application discloses a solvent recovery step for coagulation bath, including dynamic equilibrium of concentration, flocculation, ion exchange and vacuum distillation, which is an innovation of green closed-loop process; it reduces raw material costs and waste emissions. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a micrograph of the cashmere coarse wool fibers in Example 1 of this application after pretreatment.

[0026] Figure 2 This is a micrograph of a section of the regenerated protein ion solution of cashmere coarse wool fibers from Example 1 of this application.

[0027] Figure 3 This is a micrograph of cashmere regenerated protein-cellulose lyocell fiber from Example 1 of this application.

[0028] Figure 4 This is a micrograph of the pre-treated fibers of the combed short hair in Example 2 of this application;

[0029] Figure 5 This is a micrograph of a section of the regenerated protein ion solution from wool fibers in Example 2 of this application.

[0030] Figure 6 This is a micrograph of wool regenerated protein-cellulose lyocell fiber from Example 2 of this application.

[0031] Figure 7 This is a micrograph of the pre-treated fibers from the silk reeling waste in Example 3 of this application;

[0032] Figure 8This is a micrograph of a section of the silk fibroin fiber regenerated protein ion solution from Example 3 of this application.

[0033] Figure 9 This is a micrograph of silk fibroin regenerated protein-cellulose lyocell fiber from Example 3 of this application. Detailed Implementation

[0034] This application provides a method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids. The method involves preparing a two-component composite solvent by combining N-methylmorpholine bromide N-oxide ([NMMO]+Br-) with 1-ethyl-3-methylimidazolium bromide ([EMIM]+Br-), and applying it to dissolve waste wool or silk fibers to prepare an ionic solution of wool and silk fibroin regenerated protein. Then, the regenerated protein is prepared by blending wool and silk fibroin regenerated protein with cellulose to form pulp, and by dry-jet wet spinning to finally obtain regenerated protein lyocell fibers.

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or devices.

[0037] This application discloses a method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin regenerated protein using ionic liquids, comprising the following steps:

[0038] S1. After crushing, washing and bleaching the waste wool or silk fibers, dissolve them in a dissolving kettle using a two-component composite ionic liquid solvent to obtain a regenerated protein ionic solution.

[0039] S2. After filtering the protein ion solution, add pre-crushed wood pulp and thermoplastic polyurethane elastomer (TPU) and mix them together to form a uniform spinning solution.

[0040] S3. The spinning solution is extruded through a dry-jet wet-jet circular spinneret and then enters a coagulation bath to obtain regenerated protein fibers.

[0041] S4. The regenerated protein fiber is subjected to two-stage washing, stretching, oiling, drying and cutting to obtain regenerated protein lyocell fiber;

[0042] Specifically, in this application embodiment, regenerated protein lyocell fibers are prepared using cashmere coarse wool, combed short wool, and reeling waste fibers.

[0043] Example 1

[0044] Example 1 describes the preparation of a cashmere regenerated protein lyocell fiber using coarse cashmere wool as the raw material. The specific steps are as follows:

[0045] S1. Pre-treatment of waste cashmere fibers: First, the coarse cashmere fibers (containing 8.9% coarseness) are manually cleaned, washed, and bleached. Specifically, the bleaching process uses an H2O2 system. An image of the bleached cashmere fibers is shown below. Figure 1 As shown.

[0046] The coarse cashmere fibers were then dissolved in a dissolving autoclave using a bifunctional ionic liquid to obtain regenerated cashmere protein ions. The main component of the bifunctional ionic liquid was N-methylmorpholine bromide N-oxide ([NMMO)). + Br - ) and 1-ethyl-3-methylimidazolium bromide ([EMIM]) + Br - The mass ratio of N-methylmorpholine bromide N-oxide to 1-ethyl-3-methylimidazolium bromide is 90:10.

[0047] Specifically, the dissolution conditions were: temperature 90℃, time 2 hours, solid-liquid ratio 1:8, and vacuum protection. The final cashmere keratin extraction rate was 88%. Microscopic images of the ion solution sections of regenerated cashmere coarse wool fibers are shown below. Figure 2 As shown.

[0048] S2. Filter the cashmere regenerated protein ion solution to remove impurities and transfer it to another dissolving vessel; add pre-crushed and swollen wood pulp (DP≥600) and thermoplastic polyurethane elastomer (TPU), and heat and stir to form cashmere regenerated protein-cellulose blended pulp.

[0049] Specifically, the composition of the mixture consists of 65 wt% cashmere keratin fiber, 32 wt% cellulose, and 3 wt% TPU, which are mixed and stirred at 95°C for 1 hour to form a homogeneous spinning solution.

[0050] S3. The spinning solution is extruded through a 0.08 mm circular spinneret, cooled by strong axial airflow, and after passing through an air gap of 30 mm, it enters the coagulation bath to finally obtain regenerated protein fibers.

[0051] Specifically, the spinning speed was 80 m / min; and the coagulation bath contained 9 wt% [NMMO]+Br- and 1 wt% [EMIM]. + Br - Aqueous solution, temperature 25℃.

[0052] In addition, the coagulation bath is recovered. Firstly, the concentration of the coagulation bath is kept constant by continuously draining the bath and adding water or solvent. The coagulated liquid discharged from the bath contains various impurities, including low-polymerization cellulose, lignin, and hemicellulose. These components are removed through flocculation, anion exchange, and cation exchange to obtain a pure, low-concentration solvent aqueous solution. Then, the water in the recovered liquid is evaporated and concentrated to the concentration required for the process, allowing it to be reused as a solvent for preparing the spinning solution. The final solvent recovery rate is 99.0%.

[0053] S4. The regenerated protein fiber undergoes a two-stage water wash to remove residual solvent, with a washing temperature of 30℃. Then, it is stretched using rollers at a stretch ratio of 1.2. Natural plant and mineral oils are used, with the oil content controlled at 0.9%. It is then hot-air dried at 85℃. Finally, it is cut to unequal lengths. This yields cashmere regenerated protein-cellulose lyocell fiber with a length of 38mm and a fineness of 1D (9.88μm).

[0054] Specifically, micrographs of cashmere regenerated protein-cellulose lyocell fibers are shown below. Figure 3 As shown in the microscopic images, the prepared cashmere regenerated protein-cellulose lyocell fibers have a smooth surface, and the cashmere keratin and cellulose matrix inside the fibers form protein-cellulose molecular-level complex microregions, partially retaining the microfibril structure of cashmere keratin.

[0055] The cashmere regenerated protein-cellulose lyocell fiber was tested, and its strength was 2.89 cN / dtex; the cashmere regenerated protein content was 52.21%; and it was tested for protease degradation, and the protease degradation rate of the cashmere regenerated protein portion was 63.52%.

[0056] Example 2

[0057] Example 1 describes the preparation of a wool-derived protein lyocell fiber using combed short wool as the raw material. The specific steps are as follows:

[0058] S1. Pre-treat the combed short-fiber fibers by washing and bleaching (using a NaClO system). A picture of the bleached combed short-fiber fibers is shown below. Figure 1 As shown.

[0059] The combed short wool fibers were then dissolved in a dissolving autoclave using a bifunctional ionic liquid to obtain wool regenerated protein ions. The main component of the bifunctional ionic liquid was N-methylmorpholine bromide N-oxide ([NMMO)). + Br - ) and 1-ethyl-3-methylimidazolium bromide ([EMIM]) + Br - The mass ratio of N-methylmorpholine bromide N-oxide to 1-ethyl-3-methylimidazolium bromide is 98:2.

[0060] Specifically, the dissolution conditions were: temperature 80℃, time 1 hour, solid-liquid ratio 1:5, and vacuum protection. The final wool keratin extraction rate was 95%. Microscopic images of the ionic solution sections of regenerated wool coarse fiber are shown below. Figure 5 As shown.

[0061] S2. Filter the wool regenerated protein ion solution to remove impurities and transfer it to another dissolving vessel. Add pre-crushed and swollen wood pulp (DP≥600) and thermoplastic polyurethane elastomer (TPU), and heat and stir to form wool regenerated protein-cellulose blended pulp.

[0062] Specifically, the composition of the solution is as follows: wool keratin fiber 80 wt%, cellulose 18 wt%, and TPU 2 wt%; the solution is mixed and stirred at 85℃ for 0.5 h to form a homogeneous spinning solution.

[0063] S3. The spinning solution is extruded through a 0.1 mm circular spinneret, cooled by strong axial airflow, and after passing through an air gap of 10 mm, enters the coagulation bath; finally, regenerated protein fibers are obtained. Specifically, the spinning speed is 120 m / min; and the coagulation bath is 10 wt% [NMMO]. + Br - Aqueous solution, temperature 0℃.

[0064] In addition, the coagulation bath was recovered, and the recovery steps were the same as in the previous example, with a final solvent recovery rate of 99.2%.

[0065] S4. The regenerated protein fiber undergoes a two-stage water wash to remove residual solvent, with a washing temperature of 20℃. Then, it is drawn using rollers at a draw ratio of 1.5. Natural plant and mineral oils are used, with the oil content controlled at 1.2%. It is then hot-air dried at 90℃. Finally, it is cut to unequal lengths. This yields wool regenerated protein-cellulose lyocell fiber with a length of 68mm and a fineness of 1.5D (13.36μm).

[0066] Specifically, micrographs of wool-derived protein-cellulose lyocell fibers are shown below. Figure 6 As shown, the prepared wool regenerated protein-cellulose lyocell fibers have a smooth surface, and the keratin and cellulose matrix inside the fibers is a protein-cellulose molecular-level complex microregion, partially retaining the keratin microfibril structure.

[0067] In addition, the wool regenerated protein-cellulose lyocell fiber was tested, and its strength was 2.66 cN / dtex; the wool regenerated protein content was 63.72%; and it was tested for protease degradation, and the protease degradation rate of the wool regenerated protein was 81.76%.

[0068] Example 3

[0069] Example 1 describes the preparation of a regenerated silk fibroin lyocell fiber using reeled silk scraps as raw material. The specific steps are as follows:

[0070] S1. Pre-treat the reeled yarn by-products. First, wash and bleach (using a NaClO system) the yarn by-products. A picture of the bleached combed short-fiber yarn is shown below. Figure 7 As shown.

[0071] The reeled silk by-products are then dissolved in a dissolving autoclave using a bifunctional ionic liquid to obtain regenerated silk fibroin ions. The main component of the bifunctional ionic liquid is N-methylmorpholine bromide N-oxide ([NMMO)). + Br - ) and 1-ethyl-3-methylimidazolium bromide ([EMIM]) + Br - The mass ratio of N-methylmorpholine bromide N-oxide to 1-ethyl-3-methylimidazolium bromide is 80:20.

[0072] Specifically, the dissolution conditions were: temperature 90℃, time 2.5 h, solid-liquid ratio 1:10, and vacuum protection. The final silk fibroin keratin extraction rate was 92%. Microscopic images of the silk fiber regenerated protein ion solution sections are shown below. Figure 8 As shown.

[0073] S2. Filter the silk fibroin regenerated protein ion solution to remove impurities and transfer it to another dissolving vessel. Add pre-crushed and swollen wood pulp (DP≥600) and thermoplastic polyurethane elastomer (TPU), and heat and stir to form silk fibroin regenerated protein-cellulose blended pulp.

[0074] Specifically, the composition of the solution is as follows: silk fibroin fiber 45 wt%, cellulose 53 wt%, and TPU 2 wt%; the solution is mixed and stirred at 95℃ for 0.5 h to form a homogeneous spinning solution.

[0075] S3. The spinning solution is extruded through a 0.08 mm circular spinneret, cooled by strong axial airflow, and after passing through an air gap of 50 mm, enters the coagulation bath; finally, regenerated protein fibers are obtained. Specifically, the spinning speed is 40 m / min; and the coagulation bath contains 8 wt% [NMMO]. + Br - With 2wt% [EMIM] + Br - The aqueous solution is at a temperature of 35℃.

[0076] In addition, the coagulation bath was recovered, and the recovery steps were the same as in the previous example, with a final solvent recovery rate of 99.7%.

[0077] S4. The regenerated protein fiber undergoes a two-stage water washing process to remove residual solvent, with a washing temperature of 40℃. Then, it is drawn using rollers at a draw ratio of 1.3. Natural plant and mineral oils are used, with the oil content controlled at 0.8%. It is then hot-air dried at 90℃. Finally, it is cut to unequal lengths. This yields silk fibroin regenerated protein-cellulose lyocell fiber with a length of 48mm and a fineness of 1.2D (11.61μm).

[0078] Specifically, the micrographs of silk fibroin regeneration protein-cellulose lyocell fibers are as follows: Figure 9 As shown, the prepared silk fibroin regenerated protein-cellulose lyocell fibers have a smooth surface, and the keratin and cellulose matrix inside the fibers are protein-cellulose molecular-level complex microregions, partially retaining the keratin microfibril structure.

[0079] In addition, the silk fibroin regenerated protein-cellulose lyocell fiber was tested, and its strength was 3.03 cN / dtex; the silk fibroin regenerated protein content was 43.46%; and it was tested for protease degradation, and the protease degradation rate of the silk fibroin regenerated protein portion was 85.29%.

[0080] Comparative Example

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that, in step 1, 100% N-methylmorpholine bromide ([NMMO) was used. + Br - To dissolve the coarse wool fibers of cashmere, under the same conditions, none of the methods could dissolve the fibers. Therefore, 100% 1-ethyl-3-methylimidazolium bromide ([EMIM]) was used. + Br - The samples were tested to dissolve the coarse cashmere fibers, but under the same conditions, none of them could dissolve the fibers.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 1 is that in step 2, pre-crushed and swollen wood pulp (DP≥600) and thermoplastic polyurethane elastomer (TPU) were not added; instead, a uniform spinning solution of 100 wt% cashmere keratin fibers was used. In the dry-jet wet spinning process in step 3, the strength was too low to form filaments.

[0085] Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 2 is that, in step 1, 100% N-methylmorpholine bromide ([NMMO) was used. + Br - Dissolving combed short hair was not possible under the same conditions. Therefore, 100% 1-ethyl-3-methylimidazolium bromide ([EMIM]) was used. + Br - Dissolving combed short hair, under the same conditions, also failed to dissolve the fibers.

[0087] Comparative Example 4

[0088] The difference between Comparative Example 4 and Example 2 is that in step 2, pre-crushed and swollen wood pulp (DP≥600) and thermoplastic polyurethane elastomer (TPU) were not added; instead, a uniform spinning solution of 100 wt% wool keratin fibers was used. In the dry-jet wet spinning process in step 3, the strength was too low to form filaments.

[0089] Comparative Example 5

[0090] The difference between Comparative Example 5 and Example 3 is that, in step 1, 100% N-methylmorpholine bromide ([NMMO)) was used. + Br - Dissolving the reeling waste fibers under the same conditions failed. Therefore, 100% 1-ethyl-3-methylimidazolium bromide ([EMIM]) was used. + Br - Dissolving the fibers from silk reeling waste under the same conditions also failed to dissolve the fibers.

[0091] Comparative Example 6

[0092] The difference between Comparative Example 6 and Example 3 is that, in step 2, pre-crushed and swollen wood pulp (DP≥600) and thermoplastic polyurethane elastomer (TPU) were not added; instead, a uniform spinning solution of 100 wt% silk fibroin fiber was used. In the dry-jet wet spinning process in step 3, the strength was too low to form fibers.

[0093] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0094] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0095] This specification and accompanying drawings are merely illustrative examples of this application and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Therefore, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids, characterized in that, The following steps are included: S1. After crushing, washing and bleaching the waste wool or silk fibers, dissolve them in a dissolving kettle using a two-component composite ionic liquid solvent to obtain a regenerated protein ionic solution. S2. After filtering the protein ion solution, add pre-crushed wood pulp and thermoplastic polyurethane elastomer (TPU) and mix them together to form a uniform spinning solution. S3. The spinning solution is extruded through a circular spinneret and enters a coagulation bath to obtain regenerated protein fibers; S4. The regenerated protein fiber is subjected to two-stage washing, stretching, oiling, drying and cutting to obtain regenerated protein lyocell fiber; In step S1, the two-component composite ionic liquid is prepared by compounding N-methylmorpholine bromide N-oxide and 1-ethyl-3-methylimidazolium bromide in a certain mass ratio; In step S1, the mass ratio of the N-methylmorpholine bromide N-oxide to the 1-ethyl-3-methylimidazolium bromide is 80-98:20-2.

2. The method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids as described in claim 1, characterized in that, In step S1, the bleaching treatment uses an H2O2 or NaClO system.

3. The method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids as described in claim 2, characterized in that, In step S1, the dissolution conditions in the dissolving vessel are a temperature of 80-90℃, a time of 1-2.5h, and a solid-liquid ratio of 1:5-10.

4. The method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids as described in claim 1, characterized in that, In step S2, the degree of polymerization of the wood pulp is DP≥600, and the amount of thermoplastic polyurethane elastomer (TPU) added is 2-3wt%.

5. The method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin using ionic liquids as described in claim 1, characterized in that, In step S3, the coagulation bath is an aqueous solution of 8-10 wt% N-methylmorpholine bromide N-oxide and 0-2 wt% 1-ethyl-3-methylimidazolium bromide.

6. The method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin regenerated protein using ionic liquids as described in claim 5, characterized in that, The temperature of the coagulation bath is 0-35℃.

7. The method for preparing lyocell fibers based on the dissolution and recovery of wool and silk fibroin regenerated protein using ionic liquids as described in claim 5, characterized in that... The S3 step also includes the recovery of solvent from the coagulation bath, specifically as follows: By continuously draining the coagulation bath and adding water or solvent, the concentration of the coagulation bath remains constant. The coagulated liquid drained from the coagulation bath contains a variety of impurities. The coagulated liquid is then removed sequentially by flocculation, anion exchange, and cation exchange to obtain a pure, low-concentration solvent aqueous solution. The water in the low-concentration solvent aqueous solution is evaporated and recovered, then concentrated to the concentration required for the process, and used again as a solvent for preparing the spinning solution.

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