A sun-resistant silk fabric based on modified curcumin and its preparation method

Abstract

This invention relates to a lightfast silk fabric based on modified curcumin and its preparation method, belonging to the field of dyeing and finishing technology. The preparation method of this invention includes the following steps: S1, under the action of a catalyst, baicalin and dihydropyran undergo an etherification reaction in water to obtain etherified baicalin; S2, the etherified baicalin and an activator undergo an activation reaction in a solvent, and then curcumin is added to undergo an esterification reaction to obtain modified curcumin; S3, the modified curcumin is dissolved in water to obtain a finishing solution, and the silk fabric is immersed in the finishing solution for dyeing to obtain a lightfast silk fabric based on modified curcumin. By modifying the curcumin molecule with baicalin, the problems of weak UV protection and poor lightfastness of dyed silk fabrics caused by curcumin are improved, providing a safe and environmentally friendly solution for improving the lightfastness of silk fabrics dyed with natural dyes.

Description

Technical Field

[0001] This invention belongs to the field of dyeing and finishing technology, and particularly relates to a sun-resistant silk fabric based on modified curcumin and its preparation method. Background Technology

[0002] Currently, the textile industry faces numerous challenges, including restrictions or bans on the use of certain toxic and hazardous reagents and environmental pollution. Therefore, the industry urgently needs to establish an eco-friendly and sustainable dyeing and finishing system. Most natural dyes possess good biodegradability, have a relatively low environmental impact, and offer certain functionalities such as antibacterial and UV protection properties, giving them more advantages and application prospects compared to synthetic dyes. However, the use of natural dyes in textile printing and dyeing processes still presents several problems, such as incomplete color spectrum, higher costs, and poor color fastness.

[0003] Curcumin is a natural dye extracted from the rhizome of the turmeric plant. Among natural dyes, it possesses high color value and dyeing ability, making it one of the most industrialized natural dyes in the textile processing field. Existing research has shown that curcumin not only imparts excellent dyeing properties to polyester and acrylic fibers, but also, due to its excellent antibacterial properties, has been widely used in the antibacterial finishing of wool, silk, and nylon. However, the poor photostability of curcumin hinders its large-scale printing and dyeing processing on textiles. This is because the conjugated system of the diketone structure within the curcumin molecule has a high electron cloud density. Under light conditions, it absorbs light energy, its energy level increases, and it is prone to oxidation, leading to the destruction of its color development system and fading. Therefore, current technologies often use organic reagents such as sodium borohydride and p-aminobenzenesulfonic acid as raw materials to modify curcumin. Although the water solubility of modified curcumin is significantly improved, its lightfastness remains poor, and the organic reagents are highly toxic, posing certain safety hazards, which is inconsistent with the concepts of ecological textiles and green textile industry. In addition, when dyeing and finishing silk, although silk contains many reducing groups such as amino, imino and hydroxyl groups, tryptophan in silk has the ability to sensitize singlet oxygen under visible light, causing the dye on the silk to undergo photo-oxidation and fading.

[0004] Therefore, it is urgent to improve curcumin's ability to protect against ultraviolet rays and its antioxidant properties through chemical modification to enhance its photostability, so as to prepare silk fabrics with sun-resistant properties. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of poor light fastness of curcumin-dyed silk fabrics and safety hazards of curcumin-modified raw materials in the prior art.

[0006] To address the aforementioned technical problems, this invention provides a sun-resistant silk fabric based on modified curcumin and its preparation method. Utilizing the light fading mechanism of curcumin and the ultraviolet absorption and antioxidant properties of baicalin, the invention modifies curcumin molecules with baicalin without introducing additional substances that increase environmental burden. This improves the problems of weak ultraviolet protection ability of curcumin and poor light fastness of dyed silk fabrics, providing a safe and environmentally friendly solution for improving the light fastness of naturally dyed silk fabrics.

[0007] The first objective of this invention is to provide a method for preparing a sun-resistant silk fabric based on modified curcumin, comprising the following steps:

[0008] S1. Under the action of a catalyst, baicalin and dihydropyran undergo an etherification reaction in water to obtain etherified baicalin;

[0009] The etherified baicalin described in S2 and S1 and the activator are activated in a solvent, and then curcumin is added to carry out an esterification reaction to obtain modified curcumin.

[0010] S3. Dissolve the modified curcumin described in S2 in water to obtain a finishing solution, and immerse the silk fabric in the finishing solution for dyeing to obtain the sun-resistant silk fabric based on modified curcumin.

[0011] In one embodiment of the present invention, in S1, the catalyst is aluminum phosphate.

[0012] In one embodiment of the present invention, in S1, the molar ratio of baicalin, dihydropyran and catalyst is 1:(5-5.5):(0.0075-0.015).

[0013] In one embodiment of the present invention, in S1, the pH of the etherification reaction is 3-4, the temperature is 85℃-95℃, and the time is 20min-40min. The purpose of the etherification reaction is to prevent N,N-carbonyldiimidazole from simultaneously activating the phenolic hydroxyl and carboxyl groups on baicalin, thus forming a cyclic compound.

[0014] In one embodiment of the present invention, in S2, the activator is N,N-carbonyldiimidazole;

[0015] The solvent is dimethyl sulfoxide.

[0016] In one embodiment of the present invention, in S2, the molar ratio of curcumin, etherified baicalin and activator is (1:2:2)-(2:3:3).

[0017] In one embodiment of the present invention, in S2, the activation reaction is carried out at a temperature of 60°C-80°C for a time of 4-6 hours.

[0018] The esterification reaction is carried out at a temperature of 60℃-80℃ for a time of 36h-72h.

[0019] In one embodiment of the present invention, in S3, the concentration of modified curcumin in the finishing solution is 5wt%-7wt%.

[0020] In one embodiment of the present invention, in S3, the staining process is as follows: the bath ratio is 1:(30-50), the pH is 5-6, the temperature is 85℃-95℃, and the time is 50min-70min.

[0021] The second objective of this invention is to provide a sun-resistant silk fabric based on modified curcumin prepared by the aforementioned preparation method.

[0022] The technical solution of the present invention has the following advantages compared with the prior art:

[0023] (1) The preparation method described in this invention links curcumin and baicalin through an esterification reaction, without destroying the phenolic hydroxyl groups on the baicalin molecule. Modified curcumin releases phenolic hydroxyl hydrogen atoms and generates stable semiquinone free radicals, thereby terminating the free radical chain reaction and achieving antioxidant effects.

[0024] (2) The preparation method described in this invention uses baicalin to directly modify curcumin molecules. The final product does not introduce any other molecules besides baicalin. The reaction conditions are mild, energy consumption is low, and toxicity is low. That is, it only uses natural products to make up for the problem of poor light fastness on textiles, and provides a safe and environmentally friendly solution for improving the light fastness of curcumin-dyed silk fabrics.

[0025] (3) The modified curcumin in the sun-resistant silk fabric based on modified curcumin described in this invention are all natural dyes. The curcumin and etherified baicalin are linked together through esterification reaction, which reduces the burden on the environment. The modified curcumin has good sun fastness on silk fabric. Attached Figure Description

[0026] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram of the modified curcumin synthesis route of Example 1 of the present invention;

[0028] Figure 2 The infrared absorption spectra of baicalin before and after etherification in Test Example 1 of the present invention are shown.

[0029] Figure 3 The infrared absorption spectra of curcumin before and after modification in Test Example 1 of this invention are shown below.

[0030] Figure 4 This is a comparison image of silk fabrics dyed with different dyes before and after sun exposure, as shown in Test Example 3 of the present invention.

[0031] Figure 5 The graph shows the change of K / S values ​​of silk fabrics dyed with different concentrations of curcumin and modified curcumin as a function of sun exposure time in Test Example 4 of the present invention.

[0032] Figure 6 This is a comparison image of silk fabrics dyed with different concentrations of curcumin and modified curcumin before and after sun exposure, as shown in Test Example 4 of the present invention. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0034] In this invention, unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0035] In this invention, unless otherwise stated, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] In this invention, unless otherwise specified, the experimental methods used in the embodiments of this invention are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0037] Example 1

[0038] Reference Figure 1 As shown, the modified curcumin-based sun-resistant silk fabric and its preparation method in this embodiment specifically include the following steps:

[0039] S1. Dissolve 0.25g of baicalin in 30mL of deionized water, then add 0.2g of dihydropyran and 0.01g of aluminum phosphate. Adjust the pH to 3 with acetate buffer and place the solution in a 90℃ shaking water bath for 30min. After cooling, centrifuge at 4000r / min and wash with water for 10min. Repeat the centrifugation and washing with water three times to remove unreacted dihydropyran. Then filter and dry to obtain etherified baicalin powder.

[0040] S2. Dissolve 0.17g of etherified baicalin powder in 10mL of dimethyl sulfoxide, add 0.06g of N,N-carbonyldiimidazole, and react at 70℃ for 5h. After the reaction is completed, add curcumin dimethyl sulfoxide solution (0.07g of curcumin dissolved in 10mL of dimethyl sulfoxide) and continue the reaction for 48h. After the reaction is completed, pour the reaction solution into a separatory funnel, add 100mL of deionized water and 20mL of dichloromethane, shake well, release the gas, let stand for extraction, and take the lower layer of extract and distill at 40℃ to obtain modified curcumin.

[0041] S3. Dissolve modified curcumin in water to prepare a finishing solution with a concentration of 5wt%, and immerse the silk fabric in the finishing solution for dyeing to obtain a sun-resistant silk fabric based on modified curcumin. The dyeing process is as follows: the liquor ratio is 1:50, the pH is adjusted to 5.6 with acetate buffer, the fabric is dyed at room temperature, and the temperature is increased to 90℃ at a rate of 2℃ / min for 60min.

[0042] Example 2

[0043] The modified curcumin-based sun-resistant silk fabric and its preparation method in this embodiment specifically include the following steps:

[0044] S1. Dissolve 0.5g of baicalin in 30mL of deionized water, then add 0.47g of dihydropyran and 0.001g of aluminum phosphate. Adjust the pH to 3.4 with acetate buffer and place the solution in a 90℃ shaking water bath for 30min. After cooling, centrifuge at 4000r / min and wash with water for 10min. Repeat the centrifugation and washing with water three times to remove unreacted dihydropyran. Then filter and dry to obtain etherified baicalin powder.

[0045] S2. Dissolve 0.32g of etherified baicalin powder in 20mL of dimethyl sulfoxide, add 0.12g of N,N-carbonyldiimidazole, and react at 60℃ for 6h. After the reaction is completed, add curcumin dimethyl sulfoxide solution (0.14g of curcumin dissolved in 10mL of dimethyl sulfoxide) and continue the reaction for 36h. After the reaction is completed, pour the reaction solution into a separatory funnel, add 150mL of deionized water and 30mL of dichloromethane, shake well, release the gas, let stand for extraction, and take the lower layer of extract and distill at 40℃ to obtain modified curcumin.

[0046] S3. Dissolve modified curcumin in water to prepare a finishing solution with a concentration of 6wt%, and immerse the silk fabric in the finishing solution for dyeing to obtain a sun-resistant silk fabric based on modified curcumin. The dyeing process is as follows: the liquor ratio is 1:50, the pH is adjusted to 5.6 with acetate buffer, the fabric is dyed at room temperature, and the temperature is increased to 90℃ at a rate of 2℃ / min for 60min.

[0047] Example 3

[0048] The modified curcumin-based sun-resistant silk fabric and its preparation method in this embodiment specifically include the following steps:

[0049] S1. Dissolve 1g of baicalin in 50mL of deionized water, then add 0.95g of dihydropyran and 0.015g of aluminum phosphate. Adjust the pH to 3.6 with acetate buffer and place the solution in a 90℃ shaking water bath for 30min. After cooling, centrifuge at 4000r / min and wash with water for 10min. Repeat the centrifugation and washing with water three times to remove unreacted dihydropyran. Then filter and dry to obtain etherified baicalin powder.

[0050] S2. Dissolve 0.824 g of etherified baicalin powder in 10 mL of dimethyl sulfoxide, add 0.32 g of N,N-carbonyldiimidazole, and react at 80 °C for 4 h. After the reaction is complete, add curcumin dimethyl sulfoxide solution (0.4 g of curcumin dissolved in 10 mL of dimethyl sulfoxide), and continue the reaction for 36 h. After the reaction is complete, pour the reaction solution into a separatory funnel, add 200 mL of deionized water and 20 mL of dichloromethane, shake well, release the gas, let stand for extraction, and distill the lower layer of extract at 40 °C to obtain modified curcumin.

[0051] S3. Dissolve modified curcumin in water to prepare a finishing solution with a concentration of 7wt%, and immerse the silk fabric in the finishing solution for dyeing to obtain a sun-resistant silk fabric based on modified curcumin. The dyeing process is as follows: the liquor ratio is 1:50, the pH is adjusted to 5.6 with acetate buffer, the fabric is dyed at room temperature, and the temperature is increased to 90℃ at a rate of 2℃ / min for 60min.

[0052] Example 4

[0053] The modified curcumin-based sun-resistant silk fabric and its preparation method in this embodiment specifically include the following steps:

[0054] S1. Dissolve 2g of baicalin in 50mL of deionized water, then add 2g of dihydropyran and 0.03g of aluminum phosphate. Adjust the pH to 4 with acetate buffer and place the solution in a 90℃ shaking water bath for 30min. After cooling, centrifuge at 4000r / min and wash with water for 10min. Repeat the centrifugation and washing with water 3 times to remove unreacted dihydropyran. Then filter and dry to obtain etherified baicalin powder.

[0055] S2. Dissolve 1.64g of etherified baicalin powder in 10mL of dimethyl sulfoxide, add 0.65g of N,N-carbonyldiimidazole, and react at 80℃ for 4h. After the reaction is complete, add curcumin dimethyl sulfoxide solution (10mL of dimethyl sulfoxide contains 0.8g of curcumin), and continue the reaction for 72h. After the reaction is complete, pour the reaction solution into a separatory funnel, add 300mL of deionized water and 20mL of dichloromethane, shake well, release the gas, let stand for extraction, and take the lower layer of extract and distill at 40℃ to obtain modified curcumin.

[0056] S3. Dissolve modified curcumin in water to prepare a finishing solution with a concentration of 5wt%, and immerse the silk fabric in the finishing solution for dyeing to obtain a sun-resistant silk fabric based on modified curcumin. The dyeing process is as follows: the liquor ratio is 1:50, the pH is adjusted to 5.6 with acetate buffer, and the dyeing is carried out at a constant temperature of 90℃ for 60 minutes.

[0057] Example 5

[0058] The modified curcumin-based sun-resistant silk fabric and its preparation method in this embodiment specifically include the following steps:

[0059] S1. Dissolve 1g of baicalin in 50mL of deionized water, then add 0.95g of dihydropyran and 0.015g of aluminum phosphate. Adjust the pH to 3.6 with acetate buffer and place the solution in a 90℃ shaking water bath for 30min. After cooling, centrifuge at 4000r / min and wash with water for 10min. Repeat the centrifugation and washing with water three times to remove unreacted dihydropyran. Then filter and dry to obtain etherified baicalin powder.

[0060] S2. Dissolve 0.824 g of etherified baicalin powder in 10 mL of dimethyl sulfoxide, add 0.32 g of N,N-carbonyldiimidazole, and react at 80 °C for 4 h. After the reaction is complete, add curcumin dimethyl sulfoxide solution (0.4 g of curcumin dissolved in 10 mL of dimethyl sulfoxide), and continue the reaction for 36 h. After the reaction is complete, pour the reaction solution into a separatory funnel, add 200 mL of deionized water and 20 mL of dichloromethane, shake well, release the gas, let stand for extraction, and distill the lower layer of extract at 40 °C to obtain modified curcumin.

[0061] S3. Dissolve modified curcumin in water to prepare a finishing solution with a concentration of 5wt%, and immerse the silk fabric in the finishing solution for dyeing to obtain a sun-resistant silk fabric based on modified curcumin. The dyeing process is as follows: the liquor ratio is 1:50, the pH is adjusted to 5.6 with acetate buffer, and the dyeing is carried out at a constant temperature of 90℃ for 60 minutes.

[0062] Comparative Example 1

[0063] The process is basically the same as in Example 5, except that baicalin is not etherified.

[0064] Comparative Example 2

[0065] The process is basically the same as in Example 5, except that N,N-carbonyldiimidazole is not used for activation.

[0066] Comparative Example 3

[0067] The basic formula is the same as in Example 5, except that the molar ratio of baicalin and dihydropyran is changed from 1:5 to 1:10.

[0068] Comparative Example 4

[0069] The method is basically the same as in Example 5, except that baicalin is replaced with quercetin.

[0070] Test Example 1

[0071] (1) Based on Example 5, the infrared spectra of baicalin before and after etherification were measured, and the results are as follows: Figure 2 As shown. From Figure 2 It can be seen that baicalin after etherification has a wavenumber of 1111 cm⁻¹. -1 The absorption peak of the newly added ether bond is observed; wavenumber 1068 cm⁻¹ -1 The weakening of the hydroxyl absorption peak indicates that the hydroxyl groups on baicalin are protected.

[0072] (2) Based on Example 5, the infrared spectra of curcumin before and after modification were measured, and the results are as follows: Figure 3 As shown. From Figure 3 It can be seen that the unmodified curcumin at a wavenumber of 3500 cm⁻¹ -1 The modified curcumin exhibits sharp absorption peaks due to -OH stretching vibrations, while these peaks largely disappear at the same wavenumber, indicating that the hydroxyl groups in curcumin have undergone a reaction. The modified curcumin shows absorption peaks at 1750 cm⁻¹. -1 The presence of an ester bond absorption peak nearby indicates that an esterification reaction has occurred between baicalin and curcumin.

[0073] Test Example 2

[0074] Color characteristics: measured using a Hunter Lab UltraScan PRO reflectance spectrophotometer.

[0075] Color fastness: Tested according to GB / T 8427-2019 "Textiles - Tests for color fastness to artificial light: Xenon arc".

[0076] The light fastness of the modified curcumin-based light-resistant silk fabrics of Examples 1-5 and Comparative Examples 1-4 was tested for 20 hours, and the results are shown in Table 1.

[0077] Table 1 shows the relevant performance parameters of the final measured silk fabric:

[0078] Table 1

[0079]

[0080]

[0081] As can be seen from Table 1, the modified curcumin-based sun-resistant silk fabric of the embodiments has excellent light fastness.

[0082] Comparing Example 5 and Comparative Example 1, it can be seen that baicalin in Comparative Example 1 was not etherified and did not react with curcumin. This is because the etherification reactant dihydropyran was lacking, and the hydroxyl groups on the baicalin molecule were not effectively protected. Under the activation of N,N-carbonyldiimidazole, the hydroxyl and carboxyl groups of baicalin reacted to form a cyclic compound. The final product was a blended powder of activated baicalin and curcumin, and the light fastness of the dyed silk fabric was not improved.

[0083] Comparing Example 5 and Comparative Example 2, it can be seen that in Comparative Example 2, no activator N,N-carbonyldiimidazole was added, and baicalin and curcumin did not react. The final product was a blended powder of baicalin and curcumin, and the light fastness of the dyed silk fabric was not improved.

[0084] Comparing Example 5 and Comparative Example 3, it can be seen that the proportion of dihydropyran in Comparative Example 3 is too high. The activation rate of baicalin by N,N-carbonyldiimidazole is accelerated and it does not react with curcumin. Due to the excess of dihydropyran, the carboxyl group on baicalin is destroyed. After being activated by N,N-carbonyldiimidazole, it forms a ring and does not undergo esterification reaction with curcumin. The final product is a blended powder of activated baicalin and curcumin. The light fastness of the dyed silk fabric is not improved.

[0085] Comparing Example 5 and Comparative Example 4, it can be seen that the light fastness of the silk fabric prepared by quercetin-modified curcumin in Comparative Example 4 was not effectively improved, because quercetin and curcumin did not react under these conditions.

[0086] Test Example 3

[0087] Based on Test Example 5, the light fastness of silk fabrics dyed with different dyes (curcumin, baicalin, a blend of curcumin and baicalin, and modified curcumin) was investigated. The results are as follows: Figure 4 As shown in Table 2.

[0088] Figure 4 These are photos of the object before and after sun exposure (the middle part was exposed to the sun, while the sides were not).

[0089] Table 2 shows the relevant performance parameters of the final measured silk fabric:

[0090] Table 2

[0091] dye Curcumin baicalin Curcumin and baicalin blend Modified curcumin Wavelength (nm) 420 420 420 420 Before sun exposure (K / S) 23.987 0.437 26.445 13.012 After sun exposure (K / S) 3.080 0.271 3.196 7.450 Decrease rate (%) 87.16 37.84 87.91 42.74

[0092] From Table 2 and Figure 4 It can be seen that baicalin produces a colorless dye. The blending of baicalin and curcumin did not improve the lightfastness of the dyed silk fabric; the degree of fading after sun exposure was almost identical to that of silk fabric dyed with curcumin alone. This indicates that the blending of baicalin and curcumin in dyeing is merely a competition for dye sites. The K / S reduction rate of the silk fabric dyed with modified curcumin was 42.74%, which is half that of the curcumin-dyed silk fabric. This demonstrates that modifying curcumin with baicalin significantly improves the lightfastness of the dyed silk fabric, providing a green and environmentally friendly solution for improving the lightfastness of curcumin-dyed fabrics.

[0093] Test Example 4

[0094] Based on Test Example 5, the light fastness of silk fabrics dyed with curcumin solutions of different concentrations (1wt%, 5wt%, 10wt%) and modified curcumin solutions was investigated. The changes in K / S values ​​are shown in Figure 5. Figure 5 Photos of the object before and after sun exposure (the middle part was exposed to the sun, while the sides were not) are shown below. Figure 6 As shown. From Figures 5-6 It can be seen that the K / S value of unmodified curcumin-dyed silk fabrics decreases more significantly with increasing sun exposure time; the K / S value of modified curcumin-dyed silk fabrics decreases considerably after 4 hours of sun exposure, and hardly decreases with continued sun exposure. This is because modified curcumin contains a certain amount of baicalin, which releases phenolic hydroxyl hydrogen atoms to give modified curcumin its antioxidant effect, while simultaneously generating stable semi-quinone free radicals, terminating the free radical chain reaction, thereby achieving antioxidant effects. This also indicates that modifying curcumin with baicalin can effectively improve the light fastness of dyed silk fabrics.

[0095] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing sun-resistant silk fabric based on modified curcumin, characterized in that, Includes the following steps: S1. Under the action of a catalyst, baicalin and dihydropyran undergo an etherification reaction in water to obtain etherified baicalin; the molar ratio of baicalin, dihydropyran and catalyst is 1:(5-5.5):(0.0075-0.015). The etherified baicalin described in S2 and S1 and the activator are activated in a solvent, and then curcumin is added to carry out an esterification reaction to obtain modified curcumin; the activator is N,N-carbonyldiimidazole; S3. Dissolve the modified curcumin described in S2 in water to obtain a finishing solution, and immerse the silk fabric in the finishing solution for dyeing to obtain the sun-resistant silk fabric based on modified curcumin.

2. The method for preparing sun-resistant silk fabric based on modified curcumin according to claim 1, characterized in that, In S1, the catalyst is aluminum phosphate.

3. The method for preparing sun-resistant silk fabric based on modified curcumin according to claim 1, characterized in that, In S1, the pH of the etherification reaction is 3-4, the temperature is 85℃-95℃, and the time is 20min-40min.

4. The method for preparing sun-resistant silk fabric based on modified curcumin according to claim 1, characterized in that, In S2, the solvent is dimethyl sulfoxide.

5. The method for preparing sun-resistant silk fabric based on modified curcumin according to claim 1, characterized in that, In S2, the molar ratio of curcumin, etherified baicalin and activator is (1:2:2)-(2:3:3).

6. The method for preparing sun-resistant silk fabric based on modified curcumin according to claim 1, characterized in that, In S2, the activation reaction is carried out at a temperature of 60℃-80℃ for a time of 4h-6h. The esterification reaction is carried out at a temperature of 60℃-80℃ for a time of 36h-72h.

7. The method for preparing sun-resistant silk fabric based on modified curcumin according to claim 1, characterized in that, In S3, the concentration of modified curcumin in the finishing solution is 5wt%-7wt%.

8. The method for preparing sun-resistant silk fabric based on modified curcumin according to claim 1, characterized in that, In S3, the dyeing process is as follows: liquor ratio of 1:(30-50), pH of 5-6, temperature of 85℃-95℃, and time of 50min-70min.

9. The sun-resistant silk fabric based on modified curcumin prepared by the preparation method according to any one of claims 1-8.

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