Detachable silk fiber with slow-release function and preparation method thereof

Abstract

The invention discloses a detachable silk fiber with a slow release function and a preparation method thereof, and the preparation method comprises the following steps: mixing polyvinyl alcohol and deionized water to obtain a solution A; mixing the solution A with essential oil to obtain a solution B; mixing fibroin powder with deionized water to obtain a solution C; mixing the solution C and the solution B, and adding absolute ethyl alcohol to obtain a solution D; freezing the solution D, unfreezing, and centrifuging to obtain silk fibroin essential oil microcapsule powder; mixing the silk fibroin essential oil microcapsule powder with deionized water to obtain spraying liquid; and spraying the spraying liquid on the surface of the silk fiber to obtain the detachable silk fiber with the slow-release function. The prepared detachable silk fiber with the slow-release function has a long-acting slow-release function, and when the slow-release function disappears or is not needed, the protective film layer on the surface of the silk fiber can be detached.

Description

Technical Field

[0001] This invention belongs to the field of silk fiber technology, specifically relating to an unloadable slow-release functional silk fiber and its preparation method. Background Technology

[0002] Silk fiber is a natural protein fiber with a soft texture, strong skin-friendliness, and excellent mechanical properties and biocompatibility. In daily life, silk fiber is mainly used to make silk fabrics for clothing and silk quilts, which are widely loved by consumers.

[0003] However, with the improvement of deionization levels in people's lives, there are higher requirements for the functionality of silk fibers. For example, scented silk products or silk products with antibacterial and anti-mite properties are becoming increasingly popular in the consumer market. Post-processing techniques for adding fragrance, antibacterial, or anti-mite functions to silk fibers mainly include impregnation and coating. Fragrance agents and antibacterial / anti-mite agents applied directly through impregnation and coating are easily volatile and lack persistence. Therefore, the use of microencapsulation technology to encapsulate functional additives or oils is gradually increasing.

[0004] However, existing microcapsule technologies also suffer from breakage and other losses when applied to silk fibers. Furthermore, due to surface tension and other issues, application to silk fibers is difficult, requiring the addition of cross-linking agents or adhesives. This damages the natural properties of the silk fibers. Moreover, once the functional silk fibers have finished performing, the cross-linking agents or adhesives are difficult to remove. Furthermore, existing microcapsules, once loaded onto fibers, can only rely on the microcapsule wall material to control the release of functional additives, failing to achieve a truly long-lasting sustained-release effect. Summary of the Invention

[0005] The purpose of this invention is to provide a removable slow-release functional silk fiber and its preparation method. The removable slow-release functional silk fiber has a long-lasting slow-release effect, and the protective film layer on the surface of the silk fiber can be removed when the slow-release function disappears or is no longer needed.

[0006] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0007] A method for preparing unloadable, slow-release functional silk fibers, the method comprising the following steps:

[0008] Polyvinyl alcohol and deionized water are mixed to obtain solution A;

[0009] Solution A is mixed with essential oil to obtain solution B;

[0010] Silk fibroin powder and deionized water are mixed to obtain solution C;

[0011] Mix solutions C and B, then add anhydrous ethanol to obtain solution D;

[0012] Solution D was frozen, then thawed, and then centrifuged to obtain silk fibroin essential oil microcapsule powder;

[0013] Silk fibroin essential oil microcapsule powder and deionized water are mixed to obtain a spray solution;

[0014] Spraying liquid onto the surface of silk fibers yields unloadable, slow-release functional silk fibers.

[0015] In one or more embodiments of the present invention, the ratio of polyvinyl alcohol to deionized water in solution A is (2g-10g):(50ml-500ml); and / or,

[0016] In solution B, the ratio of essential oil to polyvinyl alcohol is (2ml-10ml):(2g-10g); and / or,

[0017] In solution C, the ratio of silk fibroin powder to deionized water is (1g-15g):(25ml-250ml); and / or,

[0018] In the solution D, the ratio of anhydrous ethanol to silk fibroin powder is (20ml-80ml): (1g-15g).

[0019] In one or more embodiments of the present invention, solution C and solution B are mixed according to the mass ratio of silk fibroin powder to polyvinyl alcohol of (1-15):(2-10).

[0020] In one or more embodiments of the present invention, the spray liquid is sprayed onto the surface of the silk fiber according to the mass ratio of the silk fibroin essential oil microcapsule powder to the silk fiber of (0.1-1):(1-100).

[0021] In one or more embodiments of the present invention, the preparation method further includes the following steps:

[0022] Poloxamer and deionized water were mixed to obtain solution E;

[0023] Silk fibroin essential oil microcapsule powder and solution E are mixed to obtain a spray solution;

[0024] Spraying liquid onto the surface of silk fibers yields unloadable, slow-release functional silk fibers.

[0025] In one or more embodiments of the present invention, the ratio of poloxamer to deionized water in solution E is (1g-10g): (100ml-500ml).

[0026] In one or more embodiments of the present invention, the silk fibroin essential oil microcapsule powder and solution E are mixed according to a mass ratio of (0.1-1):(1-10) of the silk fibroin essential oil microcapsule powder and poloxamer.

[0027] In one or more embodiments of the present invention, the essential oil is at least one of artemisia essential oil, osmanthus essential oil, lemongrass essential oil, and lemon essential oil.

[0028] In one or more embodiments of the present invention, the freezing conditions are: temperature -18°C to -22°C, time 24h to 48h; and / or,

[0029] The thawing operation is performed at 4℃-6℃; and / or,

[0030] The spraying pressure is 10 kPa-30 kPa, and the spraying time is 2 min-10 min.

[0031] Another specific embodiment of the present invention provides the following technical solution:

[0032] A type of unloadable slow-release functional silk fiber is prepared by the above-described preparation method.

[0033] Compared to existing technologies, this invention uses silk fibroin as the wall material to encapsulate essential oils. Silk fibroin shares the same protein source as silk fibers, making it more skin-friendly and environmentally friendly. Furthermore, it prolongs the sustained-release effect without the need for cross-linking agents or adhesives. Moreover, when the sustained-release function disappears or is no longer needed, the applied microcapsule protective film can be removed through physical cooling, making the operation simple and convenient. In addition, the removable sustained-release silk fiber of this invention can be used in clothing, apparel, or silk quilts, and can also be used for health protection, showing broad application prospects. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0035] A specific embodiment of the present invention provides a method for preparing unloadable slow-release functional silk fibers, which specifically includes the following steps:

[0036] Step 1: Mix polyvinyl alcohol and deionized water to obtain solution A.

[0037] Specifically, add 2g-10g of PVA (polyvinyl alcohol) with a degree of polymerization of 1750 to 50ml-500ml of deionized water, and stir with a magnetic thermostatic stirrer for 30min-90min to completely dissolve it in the deionized water to obtain solution A.

[0038] Step 2: Mix solution A with essential oil to obtain solution B.

[0039] Specifically, add 2ml-10ml of essential oil to solution A, and use a homogenizer to perform high-speed shearing at 12000 rpm for 3 minutes to obtain solution B. The essential oil is at least one of the following: mugwort essential oil, osmanthus essential oil, lemongrass essential oil, and lemon essential oil.

[0040] Step 3: Mix silk fibroin powder and deionized water to obtain solution C.

[0041] Specifically, add 1g-15g of silk fibroin powder to 25ml-250ml of deionized water and stir with a magnetic stirrer for 10-30min to obtain solution C.

[0042] Step 4: Mix solution C and solution B, then add anhydrous ethanol to obtain solution D.

[0043] Specifically, solution C is added to solution B, and homogenized at a speed of 2000 r / min-7000 r / min for 2 min-5 min. During the homogenization, 20 ml-80 ml of anhydrous ethanol is added dropwise to form a W / O solution D.

[0044] Step 5: Freeze solution D, then thaw it, and then centrifuge it to obtain silk fibroin essential oil microcapsule powder.

[0045] Specifically, solution D is frozen at -18 to -22°C for 24 to 48 hours, then removed and thawed at 4°C to obtain silk fibroin essential oil microcapsule solution. The silk fibroin-essential oil microcapsule solution is then centrifuged and washed with deionized water to obtain silk fibroin essential oil microcapsule powder.

[0046] Step 6: Re-encapsulate the silk fibroin protein essential oil microcapsule powder.

[0047] Specifically, at 4℃, 1g-10g of poloxamer 407 is dissolved in 100ml-500ml of deionized water to form a solution E of a certain concentration. 0.1g-1g of the previously prepared silk fibroin microcapsule powder is then placed in this solution and stirred thoroughly to obtain a spray solution, which is then stored in a storage bottle for later use.

[0048] Step 7: Spray the spray liquid onto the surface of the silk fiber to obtain unloadable slow-release functional silk fiber.

[0049] Specifically, 1-100g of silk fiber is weighed and placed in a spray chamber equipped with a storage bottle, a pressure spraying device, and other necessary equipment. The storage bottle is surrounded by a mixture of ice and deionized water to maintain the liquid (spray liquid) between 2°C and 4°C, ensuring the silk fibroin microcapsules encapsulated in the poloxamer 407 solution remain in a liquid state. The spray chamber control switch is then turned on, maintaining the nozzle pressure at 10-30 kPa for 2-10 minutes. The treated silk fiber is then placed in air to dry, resulting in unloadable, slow-release functional silk fiber with a microcapsule protective film layer on its surface.

[0050] Another specific embodiment of the present invention provides an unloadable slow-release functional silk fiber, which is prepared by the above-described preparation method.

[0051] The present invention will be further described in detail below with reference to specific embodiments.

[0052] The raw materials used in this invention are sourced from the following sources: Artemisia argyi essential oil, purchased from Shanghai Yuanye Biotechnology Co., Ltd., model S28258; Osmanthus essential oil, purchased from Shanghai Yuanye Biotechnology Co., Ltd., model S27234; PVA, purchased from Sinopharm Chemical Reagent Co., Ltd.; fibroin powder, purchased from Shanghai Yuanye Biotechnology Co., Ltd., model S27111; Poloxamer 407, purchased from Shanghai Yuanye Biotechnology Co., Ltd., model V34652; and silk fiber, purchased from Suzhou Chenzhong Silk Textile Co., Ltd., model 100% mulberry silk.

[0053] Example 1

[0054] The preparation method of the unloading slow-release functional silk fiber in this embodiment is as follows:

[0055] I. Preparation of Silk Fibroin Microcapsules

[0056] (1) Add 2g of PVA with a degree of polymerization of 1750 to 50ml of deionized water and stir with a magnetic thermostatic stirrer for 45min to completely dissolve it in the deionized water to obtain solution A.

[0057] (2) Add 4 ml of Artemisia argyi essential oil to solution A, and use a homogenizer to perform high-speed shearing at 12000 rpm for 3 min to obtain solution B.

[0058] (3) Add 2g of silk fibroin powder to 25ml of deionized water and stir with a magnetic stirrer for 15min to obtain solution C. Add it to solution B and use a homogenizer to shear it at 3000r / min for 2min. While shearing, add 20ml of anhydrous ethanol dropwise to form W / O solution D.

[0059] (4) After freezing the solution D at -18°C for 24 hours, take it out and thaw it at 4°C to obtain silk fibroin essential oil microcapsule solution. Centrifuge and wash the silk fibroin-artemisia essential oil microcapsule solution to obtain silk fibroin-artemisia essential oil microcapsule powder.

[0060] II. Finishing of Silk Fibers

[0061] (1) Place 0.1g of the previously prepared silk fibroin microcapsule powder in 200ml of deionized water, stir thoroughly to obtain a spray solution, and put it into a storage bottle for later use.

[0062] (2) Weigh 10g of silk fiber and place it in the spray chamber. The spray chamber is equipped with necessary devices such as a liquid storage bottle and a pressure spray device. The liquid storage bottle is surrounded by a mixture of ice and deionized water so that the liquid in the liquid storage bottle can be kept at 4℃.

[0063] (3) Fill the spray liquid into the storage bottle, turn on the control switch of the spray chamber, keep the nozzle pressure at 10 kPa, and spray for 2 minutes.

[0064] (4) Place the treated silk fibers in the air and dry them to obtain unloadable slow-release silk fibers.

[0065] Example 2

[0066] The preparation method of the unloading slow-release functional silk fiber in this embodiment is as follows:

[0067] I. Preparation of Silk Fibroin Microcapsules

[0068] (1) Add 2g of PVA with a degree of polymerization of 1750 to 50ml of deionized water and stir with a magnetic thermostatic stirrer for 45min to completely dissolve it in the deionized water to obtain solution A.

[0069] (2) Add 4 ml of Artemisia argyi essential oil to solution A, and use a homogenizer to perform high-speed shearing at 12000 rpm for 3 min to obtain solution B.

[0070] (3) Add 2g of silk fibroin powder to 25ml of deionized water and stir with a magnetic stirrer for 15min to obtain solution C. Add it to solution B and use a homogenizer to shear it at 3000r / min for 2min. While shearing, add 20ml of anhydrous ethanol dropwise to form W / O solution D.

[0071] (4) After freezing the solution D at -18°C for 24 hours, take it out and thaw it at 4°C to obtain silk fibroin essential oil microcapsule solution. Centrifuge and wash the silk fibroin-artemisia essential oil microcapsule solution to obtain silk fibroin-artemisia essential oil microcapsule powder.

[0072] II. Re-encapsulation of silk fibroin microcapsules

[0073] (1) At 4℃, 1g of poloxamer 407 was dissolved in 200ml of deionized water to form a solution of a certain concentration.

[0074] (2) Place 0.1g of the previously prepared silk fibroin microcapsule powder into the solution, stir thoroughly to form a spray solution, and put it into a storage bottle for later use.

[0075] III. Finishing of Silk Fibers

[0076] (1) Weigh 10g of silk fiber and place it in the spray chamber. The spray chamber is equipped with necessary devices such as a liquid storage bottle and a pressure spray device. The liquid storage bottle is surrounded by a mixture of ice and deionized water so that the liquid in the liquid storage bottle can be kept at 4℃.

[0077] (2) Fill the spray liquid into the storage bottle, turn on the control switch of the spray chamber, keep the nozzle pressure at 10 kPa, and spray for 2 minutes.

[0078] (3) Place the treated silk fibers in the air and dry them to obtain unloadable slow-release silk fibers.

[0079] Example 3

[0080] The preparation method of the unloading slow-release functional silk fiber in this embodiment is as follows:

[0081] I. Preparation of Silk Fibroin Microcapsules

[0082] (1) Add 4g of PVA with a degree of polymerization of 1750 to 150ml of deionized water and stir with a magnetic thermostatic stirrer for 60min to completely dissolve it in the deionized water to obtain solution A.

[0083] (2) Take 6 ml of osmanthus essential oil and add it to solution A. Use a homogenizer to perform high-speed shearing at 12000 rpm for 3 min to obtain solution B.

[0084] (3) Add 4g of silk fibroin powder to 50ml of deionized water and stir with a magnetic stirrer for 20min to obtain solution C. Add it to solution B and use a homogenizer to shear it at 2500r / min for 2min. While shearing, add 25ml of anhydrous ethanol dropwise to form W / O solution D.

[0085] (4) After freezing the solution D at -20°C for 24 hours, take it out and thaw it at 4°C to obtain silk fibroin-osmanthus essential oil microcapsule solution. Centrifuge and wash the silk fibroin-osmanthus essential oil microcapsule solution to obtain silk fibroin-osmanthus essential oil microcapsule powder.

[0086] II. Finishing of Silk Fibers

[0087] (1) Place 1.5g of the previously prepared silk fibroin microcapsule powder into 300ml of deionized water, stir thoroughly to obtain a spray solution, and put it into a storage bottle for later use.

[0088] (2) Weigh 10g of silk fiber and place it in the spray chamber. The spray chamber is equipped with necessary devices such as a liquid storage bottle and a pressure spray device. The liquid storage bottle is surrounded by a mixture of ice and deionized water so that the liquid in the liquid storage bottle can be kept at 4℃.

[0089] (3) Fill the spray liquid into the storage bottle, turn on the control switch of the spray chamber, keep the nozzle pressure at 10 kPa, and spray for 2 minutes.

[0090] (4) Place the treated silk fibers in the air and dry them to obtain unloadable slow-release silk fibers.

[0091] Example 4

[0092] The preparation method of the unloading slow-release functional silk fiber in this embodiment is as follows:

[0093] I. Preparation of Silk Fibroin Microcapsules

[0094] (1) Add 4g of PVA with a degree of polymerization of 1750 to 150ml of deionized water and stir with a magnetic thermostatic stirrer for 60min to completely dissolve it in the deionized water to obtain solution A.

[0095] (2) Take 6 ml of osmanthus essential oil and add it to solution A. Use a homogenizer to perform high-speed shearing at 12000 rpm for 3 min to obtain solution B.

[0096] (3) Add 4g of silk fibroin powder to 50ml of deionized water and stir with a magnetic stirrer for 20min to obtain solution C. Add it to solution B and use a homogenizer to shear it at 2500r / min for 2min. While shearing, add 25ml of anhydrous ethanol dropwise to form W / O solution D.

[0097] (4) After freezing the solution D at -20°C for 24 hours, take it out and thaw it at 4°C to obtain silk fibroin-osmanthus essential oil microcapsule solution. Centrifuge and wash the silk fibroin-osmanthus essential oil microcapsule solution to obtain silk fibroin-osmanthus essential oil microcapsule powder.

[0098] II. Re-encapsulation of silk fibroin microcapsules

[0099] (1) At 4℃, 1.5g of poloxamer 407 was dissolved in 300ml of deionized water to form a solution of a certain concentration.

[0100] (2) Place 0.3g of the previously prepared silk fibroin-osmanthus microcapsule powder into the solution, stir thoroughly, and then put it into a storage bottle for later use.

[0101] III. Finishing of Silk Fibers

[0102] (1) Weigh 10g of silk fiber and place it in the spray chamber. The spray chamber is equipped with necessary devices such as a liquid storage bottle and a pressure spray device. The liquid storage bottle is surrounded by a mixture of ice and deionized water so that the liquid in the liquid storage bottle can be kept at 4℃.

[0103] (2) Fill the spray liquid into the storage bottle, turn on the control switch of the spray chamber, keep the nozzle pressure at 10 kPa, and spray for 2 minutes.

[0104] (3) Place the treated silk fibers in the air and dry them to obtain unloadable slow-release silk fibers.

[0105] Comparative Example 1

[0106] The preparation method of the functional silk fiber in this comparative example is as follows:

[0107] (1) Take 10g of silk fiber and place it in the spray chamber. The spray chamber is equipped with necessary devices such as a liquid storage bottle and a pressure spray device. The liquid storage bottle is surrounded by a mixture of ice and deionized water so that the liquid in the liquid storage bottle can be kept at 4℃.

[0108] (2) Take 4ml of mugwort essential oil and put it into the storage bottle. Turn on the control switch of the spray chamber, keep the nozzle pressure at 10kpa, and spray for 2 minutes.

[0109] (3) Place the treated silk fibers in the air and dry them to obtain functional silk fibers.

[0110] Comparative Example 2

[0111] The preparation method of the functional silk fiber in this comparative example is as follows:

[0112] (1) Take 10g of silk fiber and place it in the spray chamber. The spray chamber is equipped with necessary devices such as a liquid storage bottle and a pressure spray device. The liquid storage bottle is surrounded by a mixture of ice and deionized water so that the liquid in the liquid storage bottle can be kept at 4℃.

[0113] (2) Take 6ml of osmanthus essential oil and put it into the storage bottle. Turn on the control switch of the spray chamber, keep the nozzle pressure at 10kpa, and spray for 2 minutes.

[0114] (3) Place the treated silk fibers in the air and dry them to obtain functional silk fibers.

[0115] The functional silk fibers in each embodiment and comparative example were characterized for the following properties:

[0116] (1) Evaluation of the durability of antibacterial properties of functional silk

[0117] Referring to the standard GB / T 20944.3-2008 "Evaluation of Antimicrobial Properties of Textiles - Part 3: Shaking Method", *Escherichia coli* and *Staphylococcus aureus* were selected as test bacteria. The antimicrobial durability of functional silk was evaluated by measuring the changes in bacterial counts in untreated silk fibers and silk fibers treated with secondary-encapsulated silk fibroin microcapsules. The storage time of functional silk fibers was 0-90 days.

[0118] (2) Evaluation of the aromatic sustained-release properties of functional silk

[0119] The functional silk fibers were first extracted with anhydrous ethanol under the following conditions: 80% ultrasonic power, 25°C, and ultrasonic treatment for 1 hour. The content of essential oil auxiliaries in the extract was then determined using a UV-1801 ultraviolet spectrophotometer. The functional silk fibers can be stored for 0-90 days.

[0120] (3) Determination of removal by functional silk treatment agent

[0121] When the sustained-release function is exhausted or no longer needed, place the functional silk in deionized water at 2-4℃ and soak for 1-2 hours. The silk fibroin essential oil microcapsules and the poloxamer substances encapsulated therein will dissolve in the deionized water. After soaking, deionize the silk fibers, dry them, and weigh the difference in weight of the silk fibers before and after soaking to determine the removal of functional substances.

[0122] Table 1. Evaluation of the antibacterial durability of functional silk fibers in Comparative Example 1 and Examples 1-2

[0123]

[0124] As shown in Table 1, the antibacterial performance of silk fabrics directly treated with Artemisia argyi essential oil is acceptable for up to 10 days, but quickly evaporates due to the volatility of the essential oil. Silk treated with silk fibroin Artemisia argyi microcapsules exhibits excellent antibacterial properties and maintains them for a longer period, though the antibacterial activity drops below 90% after two months. Silk treated with a second layer of silk fibroin Artemisia argyi microcapsules retains over 90% antibacterial activity even after three months of storage, demonstrating excellent sustained-release properties. This is related to the formation of a fine network structure on the silk fiber surface after poloxamer 407 is encapsulated in microcapsules.

[0125] Table 2. Evaluation of the aromatic sustained-release properties of functional silk fibers in Comparative Example 1 and Examples 1-2

[0126]

[0127] As shown in Table 2, the release of essential oils gradually increased over time. After 18 hours, the release rate of silk treated with silk fibroin and Artemisia argyi microcapsules reached 12.3%, significantly lower than that of silk fabrics directly treated with Artemisia argyi essential oil. This indicates that silk fibroin plays a good role in the sustained-release of Artemisia argyi essential oil. The overall release rate of silk treated with silk fibroin and Artemisia argyi microcapsules after re-encapsulation was lower than that after the first encapsulation, reflecting the necessity of re-encapsulation.

[0128] Table 3. Removal criteria of functional silk fiber treatment agent in Example 2

[0129]

[0130] As can be seen from Table 3, when the functionality of the silk is interrupted, the silk fibers become lighter after soaking at low temperature, which also indicates that the network structure formed by re-wrapping dissolves in deionized water, and the functional finishing material of the silk fibers is unloaded.

[0131] Table 4. Evaluation of the antibacterial durability of functional silk fibers in Comparative Examples 2 and Examples 3-4

[0132]

[0133] As shown in Table 4, osmanthus essential oil has a certain inhibitory effect on Escherichia coli and Staphylococcus aureus. As the amount of encapsulation increases, the antibacterial and slow-release properties under the encapsulation are still enhanced.

[0134] Table 5. Evaluation of the aromatic sustained-release properties of functional silk fibers in Comparative Examples 2 and Examples 3-4

[0135]

[0136] As shown in Table 5, the release of essential oil gradually increased over time. After 18 hours, the release of silk treated with osmanthus microcapsules reached 13.5%, which was much lower than that of silk fabrics directly treated with osmanthus essential oil. This indicates that fibroin plays a good role in the slow-release of osmanthus essential oil. The release of silk treated with osmanthus microcapsules after re-encapsulation was 11.5%, reflecting the necessity of re-encapsulation.

[0137] Table 6. Removal criteria of functional silk fiber treatment agent in Example 4

[0138]

[0139] As can be seen from Table 6, when the functionality of the silk is interrupted, the silk fibers become lighter after soaking at low temperature, which also indicates that the network structure formed by re-wrapping dissolves in deionized water, and the functional finishing material of the silk fibers is unloaded.

[0140] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of this disclosure. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this disclosure.

[0141] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing unloadable, slow-release functional silk fibers, characterized in that, The preparation method includes the following steps: Polyvinyl alcohol and deionized water are mixed to obtain solution A; Solution A is mixed with essential oil to obtain solution B; Silk fibroin powder and deionized water are mixed to obtain solution C; Mix solutions C and B, then add anhydrous ethanol to obtain solution D; Solution D was frozen, then thawed, and then centrifuged to obtain silk fibroin essential oil microcapsule powder; Silk fibroin essential oil microcapsule powder and deionized water are mixed to obtain a spray solution; Spraying liquid onto the surface of silk fibers yields unloadable, slow-release functional silk fibers.

2. The method for preparing unloadable slow-release functional silk fiber according to claim 1, characterized in that, In solution A, the ratio of polyvinyl alcohol to deionized water is (2g-10g):(50ml-500ml); and / or, In solution B, the ratio of essential oil to polyvinyl alcohol is (2ml-10ml):(2g-10g); and / or, In solution C, the ratio of silk fibroin powder to deionized water is (1g-15g):(25ml-250ml); and / or, In the solution D, the ratio of anhydrous ethanol to silk fibroin powder is (20ml-80ml): (1g-15g).

3. The method for preparing unloadable slow-release functional silk fibers according to claim 1, characterized in that, Solution C and solution B are mixed according to the mass ratio of silk fibroin powder to polyvinyl alcohol of (1-15):(2-10).

4. The method for preparing unloadable slow-release functional silk fiber according to claim 1, characterized in that, The spray solution is sprayed onto the surface of the silk fiber according to the mass ratio of the silk fibroin essential oil microcapsule powder to the silk fiber as (0.1-1):(1-100).

5. The method for preparing unloadable slow-release functional silk fiber according to claim 1, characterized in that, The preparation method further includes the following steps: Poloxamer and deionized water were mixed to obtain solution E; Silk fibroin essential oil microcapsule powder and solution E are mixed to obtain a spray solution; Spraying liquid onto the surface of silk fibers yields unloadable, slow-release functional silk fibers.

6. The method for preparing unloadable slow-release functional silk fiber according to claim 5, characterized in that, In solution E, the ratio of poloxamer to deionized water is (1g-10g): (100ml-500ml).

7. The method for preparing unloadable slow-release functional silk fiber according to claim 5, characterized in that, The silk fibroin essential oil microcapsule powder and solution E are mixed according to the mass ratio of silk fibroin essential oil microcapsule powder to poloxamer of (0.1-1):(1-10).

8. The method for preparing unloadable slow-release functional silk fiber according to claim 1, characterized in that, The essential oil is at least one of the following: artemisia essential oil, osmanthus essential oil, lemongrass essential oil, and lemon essential oil.

9. The method for preparing unloadable slow-release functional silk fiber according to claim 1, characterized in that, The freezing conditions are: temperature -18℃ to -22℃, time 24h to 48h; and / or, The thawing operation is performed at 4℃-6℃; and / or, The spraying pressure is 10 kPa-30 kPa, and the spraying time is 2 min-10 min.

10. A removable, slow-release functional silk fiber, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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