A method for preparing plush and natural silk fiber regeneration protein ion solution using brominated N-methylmorpholine N-oxide

Abstract

The present invention discloses a method for preparing a regenerated protein ion solution of plush and natural silk fiber using brominated N-methylmorpholine N-oxide. The present application provides a method for preparing a regenerated protein ion solution of plush and natural silk fiber using brominated N-methylmorpholine N-oxide, comprising the following preparation steps: alkaline enzyme combined pretreatment of plush and natural silk fiber, preparation of regenerated protein ion solution of plush and natural silk fiber, purification of regenerated protein ion solution of plush and natural silk fiber. The present application provides a method for preparing a regenerated protein ion solution of plush and natural silk fiber using brominated N-methylmorpholine N-oxide, which has the characteristics of mild preparation conditions, short reaction process, high yield, etc., and has the advantage of low energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of regenerated fiber preparation, in particular to a method for preparing a regenerated protein ion solution of plush and natural silk fiber by utilizing brominated N-methylmorpholine N-oxide. Background Art

[0002] In recent years, the use of N-methylmorpholine N-oxide (NMMO) as a solvent to prepare regenerated cellulose Lyocell fiber has laid the foundation for the preparation of green and environmentally friendly regenerated cellulose. However, N-methylmorpholine N-oxide (NMMO) dissolves cellulose slowly, consumes a lot of energy, and has a complex recycling process.

[0003] At present, among plush and natural silk fibers, plush fibers mainly include combed short hair fibers, cashmere residue fibers and plush mixed fibers; natural silk fibers mainly include silk waste fibers. The existing N-methylmorpholine N-oxide (NMMO) has difficulty in dissolving the above fibers, which restricts its wide application.

[0004] With the goal of developing a new fiber dissolution and preparation system, our team prepared N-methylmorpholine bromide N-oxide ([NMMO] + Br - ), they have higher boiling point, almost no vapor pressure, high thermal stability and chemical stability, and strong solubility, and are expected to become better environmentally friendly green solvents. They are applied to dissolve waste short fibers of wool, cashmere, and silk, and to prepare ion solutions of regenerated protein of plush and natural silk fiber, which provides a good foundation for the further extraction and application of regenerated plush and natural silk fiber protein. Summary of the invention

[0005] The present application provides a method for preparing a regenerated protein ion solution of plush and natural silk fiber by using brominated N-methylmorpholine N-oxide. The prepared regenerated protein ion solution of plush and natural silk fiber has the characteristics of mild preparation conditions, short reaction process, high yield, etc. The prepared regenerated protein ion solution of plush and natural silk fiber provides a good foundation for further extraction of regenerated plush and natural silk fiber protein, preparation of regenerated fibers, surface modification of chemical fibers and other applications of plush and natural silk fiber protein.

[0006] The present application provides a method for preparing a regenerated protein ion solution of plush and natural silk fibers using bromide N-methylmorpholine N-oxide, which is characterized by comprising the following preparation steps: alkaline enzyme combined pretreatment of plush and natural silk fibers, preparation of the regenerated protein ion solution of plush and natural silk fibers, and purification of the regenerated protein ion solution of plush and natural silk fibers.

[0007] Preferably, the alkaline enzyme combined pretreatment of the plush and natural silk fibers comprises the following steps: S1, mixing a certain weight portion of an alkaline compound and an alkaline protease in water, controlling a certain temperature and a certain time to prepare an alkaline enzyme combined treatment solution; S2, adding a certain mass of plush and natural silk fibers and the alkaline enzyme combined treatment solution into a high-temperature and high-pressure loose fiber dyeing machine, heating to a certain temperature, and treating in a water circulation for a certain time; after the treatment is completed, the treatment solution is released, and water is added for washing multiple times; and drying is carried out in a continuous drum dryer at a certain temperature to obtain pretreated plush and natural silk fibers.

[0008] By adopting the above technical scheme, the alkali-enzyme combined pretreatment can remove the scale layer or sericin on the surface of plush and natural silk fiber, loosen the cortex or sericin protein, and is conducive to forming a uniform and stable ion solution.

[0009] Preferably, the preparation of the plush and natural silk fiber regeneration protein ion solution comprises the following steps: S3, in a vacuum reactor, adding a certain mass fraction of the pretreated plush and natural silk fiber to a certain mass fraction of N-methylmorpholine bromide N-oxide ion solution; and opening the vacuum device, heating to a certain temperature under a certain vacuum degree, and hydrolyzing for a certain time under stirring conditions at a certain speed to form a plush and natural silk fiber regeneration protein ion solution;

[0010] Preferably, the purification of the plush and natural silk fiber regenerated protein ion solution includes the following steps: S4, cooling the plush and natural silk fiber regenerated protein ion solution, using a pressure filtration device to remove various impurities that cannot be dissolved in the fiber through a filter net to form a pure plush and natural silk fiber regenerated protein ion solution.

[0011] Preferably, in the alkaline-enzyme combined pretreatment step of the plush and natural silk fiber, the alkaline treatment agent is one or more of soda ash and caustic soda.

[0012] Preferably, in the alkaline enzyme combined pretreatment step of the plush and natural silk fiber, the alkaline protease includes Novo protease, Carsberg protease and Bacillus licheniformis protease.

[0013] Preferably, the weight ratio of the alkaline protease to the alkaline compound is (1-5): (1-7)

[0014] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0015] 1. The present application utilizes a mixture of alkaline compounds and alkaline proteases to pretreat the proteins on the surface and cortex of plush and natural silk fibers, remove surface grease and dirt, scale layers or sericin, and loosen the cortex or silk protein.

[0016] 2. The present application uses N-methylmorpholine bromide N-oxide to hydrolyze and dissolve wool and natural silk fibroin, thereby facilitating the formation of a uniform and stable ionic solution.

[0017] 3. The alkaline proteases used in this application include Novo protease, Carsberg protease and Bacillus licheniformis protease; Novo protease and Carsberg protease. Both proteases are produced by microorganisms, have similar properties and structures, but contain different numbers of amino acid residues. In addition, Bacillus licheniformis protease, like the above-mentioned Novo protease and Carsberg protease, can hydrolyze macromolecular proteins into products such as polypeptides and amino acids at a certain temperature and pH value, and has a strong ability to decompose proteins.

[0018] 4. The present application adopts a pressure filtration device to remove various impurities that cannot be dissolved from the regenerated protein ion solution of plush and natural silk fiber to form a pure regenerated protein ion solution of plush and natural silk fiber.

[0019] 5. The regenerated protein ion solution of plush and natural silk fiber obtained by the preparation method adopted in this application has high protein content, high extraction rate and good stability. On the basis of efficient recycling of N-methylmorpholine bromide N-oxide ion liquid, it can be used for the preparation of regenerated plush and natural silk protein fibers, and can also be used for the extraction and application of regenerated plush and natural silk protein. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 This is a process flow chart of preparing plush and natural silk fiber regeneration protein ion solution using N-methylmorpholine bromide N-oxide in an embodiment of the present application;

[0022] Figure 2 This is the appearance of the plush and natural silk regeneration protein ion solution in Examples 1-4 of the present application;

[0023] Figure 3This is a BCA test data table of the plush and natural silk regeneration protein ion solution in Examples 1-4 of the present application;

[0024] Figure 4 This is a comparison of scanning electron microscope (SEM) photos of the plush fibers in the examples of the present application after alkali-enzyme combined pretreatment. DETAILED DESCRIPTION

[0025] The present application provides a method for preparing a regenerated protein ion solution of plush and natural silk fiber by using brominated N-methylmorpholine N-oxide. The prepared regenerated protein ion solution of plush and natural silk fiber has the characteristics of mild preparation conditions, short reaction process, high yield, etc. The prepared regenerated protein ion solution of plush and natural silk fiber provides a good foundation for further extraction of regenerated plush and natural silk fiber protein, preparation of regenerated fibers, surface modification of chemical fibers and other applications of plush and natural silk fiber protein.

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products, or devices.

[0028] raw material

[0029] Soda ash CAS number: 7542-12-3 Molecular weight: 105.988 CP grade;

[0030] Caustic soda CAS No.: 7542-12-3 Molecular weight: 105.988 CP grade;

[0031] N-Methylmorpholine CAS No.: 109-02-4 Molecular weight: 101.147 CP grade;

[0032] Ferric bromide CAS number: 7727-15-3 Molecular weight: 266.694 AP grade;

[0033] Bromine CAS No.: 7726-95-6 Molecular weight: 159.808 CP grade;

[0034] Nano copper oxide CAS number: 1317-38-0 Molecular weight: 79.545 CP grade;

[0035] Hydrogen peroxide CAS number: 7722-84-1 Molecular weight: 34.015 CP grade, purity 30.0%.

[0036] Combed short hair fiber: the short hair combed off from the combing machine during worsted wool spinning.

[0037] Cashmere residue fiber: the leftover fiber after cashmere is combed, containing coarse hair and fine short hair.

[0038] Plush blended fiber: plush blended fiber formed during the preparation of various types of plush blended yarns.

[0039] Silk waste fibers: Contains natural silk fibers produced by the reeling and spinning of various types of silkworms, tussah silkworms, etc.

[0040] Alkaline protease: The main types of alkaline protease include Novo protease, Carsberg protease and Bacillus licheniformis protease. Both Novo protease and Carsberg protease are produced by microorganisms, contain different numbers of amino acid residues, and are composed of a polypeptide chain. Bacillus licheniformis protease: It is a proteolytic enzyme extracted from Bacillus licheniformis by fermentation.

[0041] Raw material example

[0042] Preparation of N-methylmorpholine bromide N-oxide ionic liquid:

[0043] According to the weight ratio, N-methylmorpholine, ferric bromide (catalyst) and deionized water are reacted in a vacuum reactor, and the vacuum degree of the vacuum reactor is controlled, and the mixture is mixed at a certain speed; the mixed solution is heated to 60°C, and a certain weight portion of bromine is dripped into the mixture during stirring, and after the reaction is completed, the mixture is filtered and cooled to obtain N-methylmorpholine bromide ionic liquid. Secondly, catalyst nano copper oxide dispersion and deionized water are added to the N-methylmorpholine bromide ionic liquid; the vacuum reactor is controlled at a certain vacuum degree and stirred evenly to obtain a mixed solution; after the mixed solution is heated to 60°C, hydrogen peroxide is slowly dripped into the mixture, and the temperature reaction time is maintained for 2 hours until the reaction end, the catalyst is filtered to remove, and the N-methylmorpholine bromide N-oxide ionic liquid is obtained by reduced pressure distillation.

[0044] Example

[0045] Reference Figure 1 , the mechanism of Examples 1-4 in the present application, wherein firstly, the wool and natural silk fiber are pretreated with alkaline enzymes, using a mixture of soda ash, caustic soda and alkaline protease to pretreat the surface and cortical layer or sericin protein of the wool and natural silk fiber, remove surface grease and dirt, and loosen the cortical layer or silk protein; secondly, vacuum bromide N-methylmorpholine N-oxide wool and natural silk fiber regeneration protein ion solution is prepared, wherein bromide N-methylmorpholine N-oxide is used to hydrolyze and dissolve the wool and natural silk fiber protein to form a uniform and stable ion solution; finally, impurities in the protein ion solution are filtered, and various impurities that cannot be dissolved are removed by using a pressure filtration device to form a pure wool and natural silk fiber regeneration protein ion solution; the specific implementation method is as follows.

[0046] Example 1

[0047] S1, mixing 1.5 parts by weight of soda ash and 1.0 parts by weight of Novo alkaline protease in 97.5 parts by weight of water at room temperature to prepare an alkaline-enzyme combined treatment solution;

[0048] S2. Add 10 parts by weight of 66-count combed short-hair fibers and 90 parts by weight of the above-prepared alkali-enzyme combined treatment solution into a high-temperature and high-pressure loose fiber dyeing machine, and treat with water circulation at 65°C for 1.5 hours; after the treatment, remove the treatment solution and wash twice with water; dry in a continuous drum dryer at 90°C to obtain pretreated wool fibers.

[0049] S3. In a vacuum reactor, add 10 parts by weight of the pretreated wool fibers obtained above into 90 parts of N-methylmorpholine bromide N-oxide ion liquid, turn on the vacuum device to a vacuum degree of 0.10 MPa, heat to 50°C, and carry out hydrolysis reaction for 1.5 hours under stirring conditions of 800 rpm; heat to 90°C, and react for 3 hours under stirring conditions of 1600 rpm to form a uniform wool fiber regenerated protein ion solution.

[0050] S4. Cool the wool fiber regeneration protein ion solution, and use a pressure filtration device to pass it through a 200-mesh filter to remove various impurities that cannot be dissolved in the fiber to form a pure wool fiber regeneration protein ion solution.

[0051] Example 2

[0052] S1. Mixing 0.5 parts by weight of caustic soda and 0.5 parts by weight of Carsberg alkaline protease in 99.0 parts by weight of water at room temperature to prepare an alkaline-enzyme combined treatment solution;

[0053] S2. Add 20 parts by weight of cashmere wool residue fiber (containing 85% fine short wool and 15% coarse wool) and 80 parts by weight of the above-prepared alkali-enzyme combined treatment solution into a high-temperature and high-pressure loose fiber dyeing machine, raise the temperature to 60°C, and circulate the water for 1 hour; after the treatment, remove the treatment solution, add water to wash twice; and dry in a continuous drum dryer at 80°C.

[0054] S3. In a vacuum reactor, add 30 parts by weight of the pretreated cashmere wool residue fiber obtained above into 70 parts of N-methylmorpholine bromide N-oxide ion liquid, turn on the vacuum device, reach a vacuum degree of 0.08 MPa, heat to 40°C, and carry out hydrolysis reaction at 600 rpm for 1 hour; heat to 80°C, and react at 1200 rpm for 2 hours to form a uniform cashmere fiber regeneration protein ion solution.

[0055] S4. Cool the cashmere fiber regeneration protein ion solution, and use a pressure filtration device to pass through a 200-mesh filter to remove various impurities that cannot be dissolved in the fiber to form a pure cashmere fiber regeneration protein ion solution.

[0056] Example 3

[0057] S1. Mix 1.0 parts by weight of a mixture of soda ash and caustic soda (weight ratio 1:1) and 0.7 parts by weight of Bacillus licheniformis alkaline protease in 98.3 parts by weight of water at room temperature to prepare an alkaline-enzyme combined treatment solution.

[0058] S2. Add 15 parts by weight of plush mixed fibers (70 count wool / down: 50 / 50 mixed combed short fibers) and 85 parts by weight of the above-prepared alkali-enzyme combined treatment solution into a high-temperature and high-pressure loose fiber dyeing machine, raise the temperature to 63°C, and circulate the water for 1 hour and 15 minutes; after the treatment, remove the treatment solution, add water to wash twice; and dry in a continuous drum dryer at 85°C.

[0059] S3. In a vacuum reactor, add 20 parts by weight of the pretreated plush fibers obtained above into 80 parts of N-methylmorpholine bromide N-oxide ion liquid, turn on the vacuum device, reach a vacuum degree of 0.09 MPa, heat to 45°C, and carry out hydrolysis reaction at 700 rpm for 1 hour and 20 minutes; heat to 85°C, and react at 1400 rpm for 2.5 hours to form a uniform plush fiber regenerated protein ion solution.

[0060] S4. Cool the above-mentioned plush fiber regeneration protein ion solution, and use a pressure filtration device to pass it through a 150-mesh filter screen to remove various impurities that cannot be dissolved in the fiber to form a pure plush fiber regeneration protein ion solution.

[0061] Example 4

[0062] S1. Mix 0.5 parts by weight of a mixture of soda ash and caustic soda (weight ratio 1:1) and 0.8 parts by weight of Bacillus licheniformis alkaline protease in 99.7 parts by weight of water at room temperature to prepare an alkaline-enzyme combined treatment solution.

[0063] S2. Add 18 parts by weight of mulberry silk waste fibers and 82 parts by weight of the above-prepared alkali-enzyme combined treatment solution into a high-temperature and high-pressure loose fiber dyeing machine, raise the temperature to 63°C, and circulate the water for 1 hour and 15 minutes; after the treatment, discharge the treatment solution, add water to wash twice; and dry in a continuous drum dryer at 85°C.

[0064] S3. In a vacuum reactor, add 18 parts by weight of the pretreated mulberry silk waste fibers obtained above into 82 parts of N-methylmorpholine bromide N-oxide ion liquid, and turn on the vacuum device to a vacuum degree of 0.08 MPa, heat to 40°C, and carry out hydrolysis reaction at 800 rpm for 1 hour; heat to 80°C, and react at 1500 rpm for 2 hours to form a uniform natural silk fiber regenerated protein ion solution.

[0065] S4. Cool the above-mentioned natural silk fiber regeneration protein ion solution, and use a pressure filtration device to pass through a 200-mesh filter to remove various impurities that cannot be dissolved in the solution to form a pure natural silk fiber regeneration protein ion solution.

[0066] According to the above examples 1-4, the weight proportions of the alkaline enzyme combined treatment solution in examples 1-4 are summarized as follows Table 1. The weight proportions of the alkaline enzyme combined treatment solution for treating wool fibers and reacting with brominated N-methylmorpholine N-oxide in examples 1-4 are summarized as follows Table 2 and Table 3.

[0067] Table 1. Weight proportions of each component in the alkali-enzyme combined treatment solution

[0068]

[0069] Table 2. Weight percentage of raw materials for pretreatment of plush and natural silk fiber

[0070]

[0071] Table 3. Weight percentage of raw materials of plush and natural silk fiber regeneration protein ion solution

[0072]

[0073] Comparative Example

[0074] Comparative Example 1

[0075] The difference between Comparative Example 1 and Example 1 is that in S3, unbrominated N-methylmorpholine N-oxide (i.e., conventional solvent N-methylmorpholine N-oxide ionic liquid (NMMO)) is used to prepare the regenerated protein ion solution for combed short hair fibers.

[0076] Comparative Example 2

[0077] The difference between Comparative Example 2 and Example 2 is that in S3, unbrominated N-methylmorpholine N-oxide (i.e., conventional solvent N-methylmorpholine N-oxide ionic liquid (NMMO)) is used to prepare the regenerated protein ion solution of cashmere wool residue fibers.

[0078] Comparative Example 3

[0079] The difference between Comparative Example 3 and Example 3 is that in S3, unbrominated N-methylmorpholine N-oxide (ie, conventional solvent N-methylmorpholine N-oxide ionic liquid (NMMO)) is used to prepare the regenerated protein ion solution for the plush mixed fiber.

[0080] Comparative Example 4

[0081] The difference between Comparative Example 4 and Example 4 is that in S3, unbrominated N-methylmorpholine N-oxide (i.e., conventional solvent N-methylmorpholine N-oxide ionic liquid (NMMO)) is used to prepare the regenerated protein ion solution of mulberry silk waste fibers.

[0082] Comparative Example 5

[0083] The difference between Comparative Example 5 and Example 1 is that in S1, soda ash is used to pretreat the combed short hair fibers.

[0084] Comparative Example 6

[0085] The difference between Comparative Example 6 and Example 1 is that in S1, the combed short hair fibers are pretreated by Novo alkaline protease.

[0086] Performance testing experiment

[0087] The pure cashmere fiber regenerated protein ion solutions prepared in Examples 1-4 and Comparative Examples 1-5 were subjected to BCA protein content testing, and the results are shown in Table 4.

[0088] Table 4. Test table of Examples 1-4 and Comparative Examples 1-5

[0089]

[0090] According to Table 4, the protein content of plush and natural silk regenerated protein ion solutions was detected for Examples 1-4 and Comparative Examples 1-6 of the present application. Data analysis was performed for Examples 1-4 and Comparative Examples 1-4, wherein unbrominated N-methylmorpholine N-oxide ion liquid (i.e., conventional conventional solvent N-methylmorpholine N-oxide ion liquid (NMMO)) was used to prepare regenerated protein ion solutions for combed short hair fibers, cashmere residue fibers, plush mixed fibers, and mulberry silk waste fibers, wherein the four fibers were completely not dissolved, and the plush protein content in the regenerated protein ion solution of the plush fibers finally obtained was 0.

[0091] In addition, in the analysis between Example 1 and Comparative Examples 5-6, the combed short hair fibers were dissolved at the same time, the wool fibers were not pretreated with soda ash, or the wool fibers were not pretreated with protease, and the regenerated protein content of the wool fiber regenerated protein ion solution finally obtained was lower than the regenerated protein content in Example 1. And from the appearance, the wool fiber regenerated protein ion solution in Comparative Examples 4-5 was a brown viscous liquid with undissolved fibers, and the protein content was significantly reduced after purification.

[0092] In addition, refer to Figure 2 and Figure 3 , analyze and compare Examples 1-4. The wool fiber regenerated protein ion solution prepared in Example 1 has an appearance of a brown-yellow viscous liquid, wherein the wool regenerated protein content is 8.96%, and the extraction rate is 95.0%. There is no change after being placed at room temperature for more than one year, and it has good stability. In addition, the cashmere fiber regenerated protein ion solution prepared in Example 2 of the present application has an appearance of a brown viscous liquid, a protein content of 27.25%, and an extraction rate of 85.0%; and the plush fiber regenerated protein ion solution prepared in Example 3 has an appearance of a brown-yellow viscous liquid, a protein content of 18.13%, and an extraction rate of 90.0%. The natural silk fiber regenerated protein ion solution prepared in Example 4 has an appearance of a brown-yellow viscous liquid, a protein content of 16.86%, and an extraction rate of 92.0%.

[0093] Reference Figure 4 The surface scale layer of wool fiber and cashmere fiber treated with alkali enzyme is completely dissolved, which helps to form the regenerated protein ion solution of cashmere fiber.

[0094] The prepared wool and natural silk fiber regenerated protein ion solution provides a good foundation for further development of regenerated wool and natural silk fiber protein extraction, regenerated fiber preparation, chemical fiber surface modification and other applications of wool and natural silk fiber protein.

[0095] It should be noted that the above-mentioned sequence of the embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above-mentioned specific embodiments of this specification are described. Other embodiments are within the scope of the attached claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0096] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

[0097] This specification and drawings are merely exemplary illustrations of the present application and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, a person skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the present application and its equivalents, the present application intends to include these modifications and variations.

Claims

1. A method for preparing a regenerated protein ion solution of plush and natural silk fiber using bromide N-methylmorpholine-N-oxide, characterized in that: The method comprises the following preparation steps: alkali-enzyme combined pretreatment of plush and natural silk fiber, preparation of plush and natural silk fiber regeneration protein ion solution, purification of plush and natural silk fiber regeneration protein ion solution; In the step of the alkaline enzyme combined pretreatment of the plush and natural silk fiber, it is necessary to carry out the combined pretreatment by using an alkaline compound and an alkaline protease; The preparation of the plush and natural silk fiber regenerated protein ion solution includes the following operating steps: reacting N-methylmorpholine, ferric bromide catalyst and deionized water in a vacuum reactor according to a weight ratio, controlling the vacuum degree of the vacuum reactor and mixing at a certain speed; heating the mixed solution to 60°C, dripping a certain weight portion of bromine during stirring, filtering and cooling after the reaction is completed to obtain N-methylmorpholine bromide ion liquid; adding catalyst nano copper oxide dispersion and deionized water to the N-methylmorpholine bromide ion liquid; controlling the vacuum reactor at a certain vacuum degree to stir it evenly to obtain a mixed solution; heating the mixed solution to 60°C, slowly dripping hydrogen peroxide, maintaining the temperature for 2 hours until the reaction end, filtering to remove the catalyst, and obtaining N-methylmorpholine bromide N-oxide ion liquid through reduced pressure distillation.

2. The method for preparing plush and natural silk fiber regenerated protein ion solution using brominated N-methylmorpholine-N-oxide as claimed in claim 1, characterized in that: The alkali-enzyme combined pretreatment of the plush and natural silk fiber comprises the following steps: S1, mixing a certain weight portion of an alkaline compound and an alkaline protease in water, controlling a certain temperature and a certain time, to prepare an alkaline-enzyme combined treatment solution; S2. Add a certain mass of plush and natural silk fiber and the alkaline enzyme combined treatment solution into a high-temperature and high-pressure loose fiber dyeing machine, heat it to a certain temperature, and treat it in a water circulation for a certain period of time; after the treatment, release the treatment solution, add water to wash several times; dry it in a continuous drum dryer at a certain temperature to obtain pretreated plush and natural silk fiber.

3. The method for preparing plush and natural silk fiber regenerated protein ion solution using brominated N-methylmorpholine-N-oxide as claimed in claim 2, characterized in that: The preparation of the plush and natural silk fiber regeneration protein ion solution comprises the following steps: S3. In a vacuum reactor, a certain mass fraction of the pretreated plush and natural silk fiber is added to a certain mass fraction of N-methylmorpholine bromide-N-oxide ion liquid; and the vacuum device is turned on to a certain vacuum degree, heated to a certain temperature, and hydrolyzed for a certain time under stirring conditions at a certain speed to form a plush and natural silk fiber regenerated protein ion solution.

4. The method for preparing plush and natural silk fiber regenerated protein ion solution using brominated N-methylmorpholine-N-oxide as claimed in claim 3, characterized in that: The purification of the plush and natural silk fibroin regeneration protein ion solution comprises the following steps: S4, cooling the wool and natural silk fiber regeneration protein ion solution, and using a pressure filtration device to remove various impurities that cannot be dissolved in the fiber through a filter screen to form a pure wool and natural silk fiber regeneration protein ion solution.

5. The method for preparing plush and natural silk fiber regenerated protein ion solution using brominated N-methylmorpholine-N-oxide as claimed in claim 2, characterized in that: In the alkaline-enzyme combined pretreatment step of the plush and natural silk fiber, the alkaline compound is one or more of soda ash and caustic soda.

6. The method for preparing plush and natural silk fiber regenerated protein ion solution using brominated N-methylmorpholine-N-oxide as claimed in claim 5, characterized in that: In the alkaline enzyme combined pretreatment step of the plush and natural silk fiber, the alkaline protease includes: Novo protease, Carsberg protease and Bacillus licheniformis protease.

7. The method for preparing plush and natural silk fiber regenerated protein ion solution using brominated N-methylmorpholine-N-oxide as claimed in claim 6, characterized in that: The weight ratio of the alkaline protease to the alkaline compound is (1-5):(1-7).

8. The method for preparing plush and natural silk fiber regenerated protein ion solution using brominated N-methylmorpholine-N-oxide as claimed in claim 1, characterized in that: The wool and natural silk fibers include combed short-hair fibers, cashmere residue fibers, wool mixed fibers, and silk waste fibers.

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