Anti-ultraviolet anti-aging fiber and preparation method thereof
By preparing UV-resistant and anti-aging fibers, the photoaging problem of polyester fibers has been solved, the UV protection and antibacterial properties have been improved, the fiber life has been extended, and environmental pollution has been reduced.
Patent Information
- Application Number
- CN202511988332.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-02-10
AI Technical Summary
Polyester fibers are prone to photoaging under long-term sunlight exposure, which leads to molecular chain breakage, decreased strength and yellowing. At the same time, its production process is energy-intensive and it is difficult to degrade naturally after disposal, causing microplastic pollution.
UV-resistant and anti-aging fibers were prepared by alkali-treated polyester fibers, which were then impregnated in a solution of zinc oxide-thiolized chitosan, followed by melt spinning and thermosetting processes. UV-absorbing structural units were synthesized by esterification of methyl ferulic acid and succinic anhydride, and the UV shielding effect was enhanced by loading nano-zinc oxide with chitosan modification.
It significantly improves the UV protection function and molecular stability of the fiber, endows it with antibacterial properties, extends the service life of the fiber, and reduces environmental pollution.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of functional fiber materials technology, specifically to an anti-ultraviolet and anti-aging fiber and its preparation method. Background Technology
[0002] Polyester fiber is one of the most widely used synthetic fibers. It is stable at room temperature, has high strength, good abrasion resistance, and is resistant to acid and alkali corrosion. It also possesses excellent hydrophobicity and dimensional stability, making it widely used in textiles, apparel, home textiles, and industrial textiles, such as outerwear fabrics, curtains, tire cords, and outdoor protective materials. However, polyester fiber molecular chains lack UV-resistant structures, making them prone to photoaging under prolonged sunlight exposure. This leads to molecular chain breakage, decreased strength, and yellowing, affecting the lifespan of finished products. Furthermore, its raw materials are derived from petrochemical products, resulting in high energy consumption during production. After disposal, it is difficult to degrade naturally, easily causing microplastic pollution.
[0003] In recent years, with the rapid development of industries such as outdoor sports and smart wearables, the market demand for functional and durable textile materials has been increasing. The consumption of polyester fibers has continued to rise, significantly increasing the exposure of polyester products to ultraviolet radiation during use, leading to more prominent aging and failure issues. At the same time, a large amount of discarded textiles is also putting continuous pressure on the environment. Therefore, in order to extend the lifespan of textile products and reduce petroleum resource consumption and environmental pollution, it is urgent to physically and chemically modify polyester fibers to endow them with long-lasting UV resistance and anti-aging properties, and improve their environmental compatibility. Summary of the Invention
[0004] The purpose of this invention is to provide an anti-ultraviolet and anti-aging fiber and its preparation method, so as to solve the problems existing in the prior art.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An anti-ultraviolet and anti-aging fiber is obtained by impregnating anti-ultraviolet polyester fiber with an alkali-treated solution of zinc oxide-thiolized chitosan, followed by drying and curing.
[0006] As an optimization, the UV-protective polyester fiber is obtained by melt spinning after polycondensation reaction of UV-protective intermediate with 1,3-propanediol and terephthalic acid.
[0007] As an optimization, the UV-protective intermediate is prepared by esterification of methyl ferulic acid and succinic anhydride followed by hydrolysis and acidification.
[0008] As an optimization, the zinc oxide-loaded thiolized chitosan is prepared by degrading and thiolizing chitosan and then loading it with nano-zinc oxide.
[0009] A method for preparing UV-protective and anti-aging fibers includes the following preparation steps: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine and triethylamine in a molar ratio of 1:(1.05~1.5):(0.05~0.15):(1.5~2). Dissolve methyl ferulic acid in anhydrous pyridine at 10~15wt%. Add 4-dimethylpyridine, triethylamine and succinic anhydride at 25~30℃ and 200~400r / min. Continue stirring for 4~8h. Precipitate in ice water, wash, and obtain methyl ferulic acid succinic acid monoester; in a molar ratio of 1:(0.65~0.90):(0.15~0.35):(0.0001~0.0003). Weigh out 1,3-propanediol, terephthalic acid, methyl ferulic acid succinate monoester, and zirconium acetylacetonate. Mix the 1,3-propanediol, methyl ferulic acid succinate monoester, and zirconium acetylacetonate, and react them at 160-200℃ and 200-400 r / min for 1-2 h. Add terephthalic acid, continue stirring for 2-3 h, raise the temperature to 200-240℃, maintain the reaction vacuum degree below 100 Pa, and continue stirring for 4-7 h to obtain UV-protective modified polyester. Melt-spin the UV-protective modified polyester to produce UV-protective polyester fiber. (2) Disperse chitosan at 15-25 wt% in deionized water, stir at 40-60℃ and 200-400 r / min for 1-2 h, add 6-8 wt% hydrogen peroxide to the system, heat to 60-80℃ and stir for 2-4 h, filter, and precipitate with anhydrous ethanol to obtain soluble chitosan; weigh soluble chitosan and thiourea at a mass ratio of 1:1-1.5, dissolve soluble chitosan at 1.5-2.5 wt% in 1% acetic acid solution to obtain chitosan solution; dissolve thiourea at 30-40 wt% in 6M hydrochloric acid aqueous solution, and add dropwise to the chitosan solution while stirring at 25-30℃ and 200-400 r / min. In the chitosan solution, the pH was adjusted to 4-5.5 with 0.1M acetic acid, and stirring was continued for 10-20 min to obtain a mixed solution. The mixed solution was placed in a microwave reactor and refluxed at 640W for 4-8 min. After cooling, the pH was adjusted to 8 with 1M sodium hydroxide, ethanol was used for precipitation, and the mixture was washed to obtain thiolized chitosan. The thiolized chitosan was dissolved in 1% acetic acid solution at 1.5-2.5 wt%, and 0.005-0.1 times the mass of thiolized chitosan nano-zinc oxide powder was added. The mixture was stirred at 20-30℃ and 600-700 r / min for 4-8 h, ethanol was used for precipitation, and the mixture was washed to obtain zinc oxide-loaded thiolized chitosan. (3) Weigh zinc oxide-loaded thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:(0.45~0.55):(0.75~0.85. Dissolve the zinc oxide-loaded thiolized chitosan in 1% acetic acid solution at 1~2wt%. Add sodium acetate and malic acid to the solution and stir at 200~400r / min for 10~30min at 25~30℃ to obtain a zinc oxide-loaded thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-loaded thiolized chitosan solution and stir at 50~100r / min for 20~40min at 25~30℃. Dry the fiber and cure it at 80~100℃ for 10~30min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber.
[0010] As an optimization, the key process parameters for melt spinning in step (1) are as follows: spinning temperature 260~280℃, screw speed 35~45r / min, side blowing speed 0.5~0.7m / s, first drafting roller speed 1860~1980m / min, second drafting roller speed 4800~4850m / min, winding speed 4745~4800m / min, and draw ratio 2.58.
[0011] As an optimization, the degree of deacetylation of the chitosan in step (2) is 90%, and the molecular weight is 10~20kDa; the purity of the nano zinc oxide powder is 99.9%, and the average particle size is 30nm.
[0012] As an optimization, the alkali treatment method for the UV-resistant polyester fiber in step (3) is as follows: Sodium hydroxide, hexadecyltrimethylammonium bromide and deionized water are mixed and dissolved in a volume ratio of 1:(0.15~5):(900~1000) to obtain an alkali treatment solution. The UV-resistant polyester fiber is immersed in the alkali treatment solution and treated at 90°C for 1 hour. After washing with water, it is dried for later use.
[0013] Compared with the prior art, the beneficial effects achieved by the present invention are: In preparing UV-protective and anti-aging fibers, this invention involves esterifying methyl ferulic acid with succinic anhydride to synthesize methyl ferulic acid succinic acid monoester; then, through a polycondensation reaction, methyl ferulic acid succinic acid monoester is reacted with 1,3-propanediol and terephthalic acid to obtain a UV-protective modified polyester, which is then melt-spun into UV-protective polyester fibers; chitosan is degraded, thiolated, and then loaded with nano-zinc oxide to obtain a zinc oxide-loaded thiolated chitosan solution; finally, the UV-protective polyester fibers are treated with alkali and then impregnated in the zinc oxide-loaded thiolated chitosan solution, followed by drying and curing to obtain the UV-protective and anti-aging fibers.
[0014] First, methyl ferulic acid and succinic anhydride were used as starting materials in the preparation process to synthesize methyl ferulic acid succinic acid monoester through a catalytic reaction. The cinnamic acid ester structure in methyl ferulic acid succinic acid monoester is a key group for ultraviolet absorption. The reaction with succinic anhydride effectively expanded its conjugated system, significantly improving the ultraviolet absorption performance and molecular stability. Subsequently, the intermediate was co-polymerized with 1,3-propanediol and terephthalic acid in a zirconium-titanium composite catalyst system, successfully embedding the ultraviolet absorption structural unit into the polyester molecular backbone. The ultraviolet-protective polyester fiber was obtained by melt spinning, giving the fiber body a long-lasting and stable ultraviolet protection function.
[0015] Secondly, thiolized chitosan was prepared by hydrogen peroxide degradation and thiourea modification of chitosan. The introduction of thiol groups greatly improved the antioxidant properties of chitosan. Then, by loading nano-zinc oxide, a zinc oxide-loaded thiolized chitosan functional system was constructed. The nano-zinc oxide not only synergistically enhances the overall UV shielding effect by scattering and absorbing ultraviolet rays with the UV-protective polyester matrix, but also endows the material with excellent broad-spectrum antibacterial properties. Finally, the functional layer was firmly cross-linked onto the fiber surface through impregnation coating and thermosetting processes, forming a dense and durable multifunctional protective layer. Thus, the fiber simultaneously achieved multiple functions of UV protection, anti-aging, and antibacterial properties, significantly expanding the application fields of the fiber. Detailed Implementation
[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0017] To more clearly illustrate the method provided by the present invention, the following embodiments will be described in detail. Example 1:
[0018] A method for preparing an anti-ultraviolet and anti-aging fiber mainly includes the following preparation steps: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine, and triethylamine in a molar ratio of 1:1.05:0.05:1.5. Dissolve methyl ferulic acid in anhydrous pyridine at 10 wt%. Add 4-dimethylpyridine, triethylamine, and succinic anhydride while stirring at 200 r / min at 25 °C. Continue stirring for 4 h, precipitate in ice water, wash, and obtain methyl ferulic acid succinic acid monoester. Weigh 1, 3-Propanediol, terephthalic acid, methyl ferulic acid succinate monoester, and zirconium acetylacetonate were mixed and reacted at 160℃ and 200 r / min for 1 h with stirring. Terephthalic acid was then added, and stirring was continued for 2 h. The temperature was raised to 200℃, and the reaction vacuum was maintained below 100 Pa. Stirring was continued for 4 h to obtain a UV-protective modified polyester. The UV-protective modified polyester was melt-spun into UV-protective polyester fibers. (2) Chitosan was dispersed in deionized water at 15 wt%, stirred at 40 °C and 200 r / min for 1 h, 6 wt% hydrogen peroxide was added to the system, the temperature was raised to 60 °C and stirred for 2 h, filtered and precipitated with anhydrous ethanol to obtain soluble chitosan; soluble chitosan and thiourea were weighed at a mass ratio of 1:1.3, and soluble chitosan was dissolved in 1% acetic acid solution at 1.5 wt% to obtain chitosan solution; thiourea was dissolved in 6M hydrochloric acid aqueous solution at 30 wt%, and added dropwise to chitosan solution at 25 °C and 200 r / min with stirring. In the first step, the pH was adjusted to 5 with 0.1M acetic acid, and stirring was continued for 10 min to obtain a mixed solution. The mixed solution was placed in a microwave reactor and refluxed at 640W for 7 min. After cooling, the pH was adjusted to 8 with 1M sodium hydroxide, ethanol was used for precipitation, and the mixture was washed to obtain thiolized chitosan. The thiolized chitosan was dissolved in 1% acetic acid solution at 1.5 wt%, and 0.05 times the mass of nano zinc oxide powder was added according to the mass of thiolized chitosan. The mixture was stirred at 20℃ and 600 r / min for 4 h, ethanol was used for precipitation, and the mixture was washed to obtain zinc oxide-loaded thiolized chitosan. (3) Weigh zinc oxide-thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:0.45:0.75. Dissolve the zinc oxide-thiolized chitosan in 1% acetic acid solution at 1 wt%. Add sodium acetate and malic acid to the solution and stir at 25°C and 200 r / min for 10 min to obtain zinc oxide-thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-thiolized chitosan solution and stir at 25°C and 50 r / min for 20 min. Dry the fiber and cure it at 80°C for 10 min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber. Example 2:
[0019] A method for preparing an anti-ultraviolet and anti-aging fiber mainly includes the following preparation steps: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine and triethylamine in a molar ratio of 1:1.3:0.1:1.8. Dissolve methyl ferulic acid in anhydrous pyridine at 13 wt%. Add 4-dimethylpyridine, triethylamine and succinic anhydride under stirring at 27 °C and 300 r / min. Continue stirring for 6 h. Precipitate in ice water, wash, and obtain methyl ferulic acid succinic acid monoester. Weigh 1,3-propanediol in a molar ratio of 1:0.8:0.25:0.0002. 1,3-Propanediol, methyl ferulic acid succinate monoester, and zirconium acetylacetonate were mixed and reacted at 180°C and 300 rpm for 1.5 h with stirring. Then, terephthalic acid was added, and stirring was continued for 2.5 h. The temperature was raised to 220°C, and the reaction vacuum was kept below 100 Pa. Stirring was continued for 6 h to obtain UV-protective modified polyester. The UV-protective modified polyester was melt-spun into UV-protective polyester fibers. (2) Chitosan was dispersed in deionized water at 20 wt%, stirred at 50 °C and 300 r / min for 1.5 h, 7 wt% hydrogen peroxide was added to the system, the temperature was raised to 70 °C and stirred for 3 h, filtered, and precipitated with anhydrous ethanol to obtain soluble chitosan; soluble chitosan and thiourea were weighed at a mass ratio of 1:1.3, and soluble chitosan was dissolved in 1% acetic acid solution at 2 wt% to obtain chitosan solution; thiourea was dissolved in 6M hydrochloric acid aqueous solution at 35 wt%, and added dropwise to the chitosan solution at 27 °C and 300 r / min with stirring. In the solution, the pH was adjusted to 5 with 0.1M acetic acid, and stirring was continued for 15 min to obtain a mixed solution. The mixed solution was placed in a microwave reactor and refluxed at 640W for 7 min. After cooling, the pH was adjusted to 8 with 1M sodium hydroxide, ethanol was used for precipitation, and the solution was washed to obtain thiolized chitosan. The thiolized chitosan was dissolved at 2 wt% in 1% acetic acid solution, and 0.05 times the mass of nano zinc oxide powder was added according to the mass of thiolized chitosan. The mixture was stirred at 25℃ and 650 r / min for 6 h, ethanol was used for precipitation, and the solution was washed to obtain zinc oxide-loaded thiolized chitosan. (3) Weigh zinc oxide-thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:0.5:0.8. Dissolve the zinc oxide-thiolized chitosan in 1% acetic acid solution at 1.5 wt%. Add sodium acetate and malic acid to the solution and stir at 27°C and 300 r / min for 20 min to obtain zinc oxide-thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-thiolized chitosan solution and stir at 27°C and 75 r / min for 30 min. Dry the fiber and cure it at 90°C for 20 min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber. Example 3:
[0020] A method for preparing an anti-ultraviolet and anti-aging fiber mainly includes the following preparation steps: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine and triethylamine in a molar ratio of 1:1.5:0.15:2. Dissolve methyl ferulic acid in anhydrous pyridine at 15wt%. Add 4-dimethylpyridine, triethylamine and succinic anhydride under stirring at 30℃ and 400r / min. Continue stirring for 8h. Precipitate in ice water, wash, and obtain methyl ferulic acid succinic acid monoester. Weigh 1,3 1,3-Propane glycol, methyl ferulic acid succinate monoester, and zirconium acetylacetonate were mixed and reacted at 200°C and 400 r / min for 2 h with stirring. Then, terephthalic acid was added, and stirring was continued for 3 h. The temperature was raised to 240°C, and the reaction vacuum was kept below 100 Pa. Stirring was continued for 7 h to obtain a UV-protective modified polyester. The UV-protective modified polyester was melt-spun into UV-protective polyester fibers. (2) Chitosan was dispersed in deionized water at 25 wt%, stirred at 60 °C and 400 r / min for 2 h, 8 wt% hydrogen peroxide was added to the system, the temperature was raised to 80 °C and stirred for 4 h, filtered and precipitated with anhydrous ethanol to obtain soluble chitosan; soluble chitosan and thiourea were weighed at a mass ratio of 1:1.3, and soluble chitosan was dissolved in 1% acetic acid solution at 2.5 wt% to obtain chitosan solution; thiourea was dissolved in 6M hydrochloric acid aqueous solution at 40 wt%, and added dropwise to chitosan solution at 30 °C and 400 r / min with stirring. In the first step, the pH was adjusted to 5 with 0.1M acetic acid, and stirring was continued for 20 min to obtain a mixed solution. The mixed solution was placed in a microwave reactor and refluxed at 640W for 7 min. After cooling, the pH was adjusted to 8 with 1M sodium hydroxide, ethanol was used for precipitation, and the mixture was washed to obtain thiolized chitosan. The thiolized chitosan was dissolved in 1% acetic acid solution at 2.5 wt%, and 0.05 times the mass of nano zinc oxide powder was added according to the mass of thiolized chitosan. The mixture was stirred at 30℃ and 700 r / min for 8 h, ethanol was used for precipitation, and the mixture was washed to obtain zinc oxide-loaded thiolized chitosan. (3) Weigh zinc oxide-thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:0.55:0.85. Dissolve 2 wt% of the zinc oxide-thiolized chitosan in a 1% acetic acid solution. Add sodium acetate and malic acid to the solution and stir at 30°C and 400 r / min for 30 min to obtain a zinc oxide-thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-thiolized chitosan solution and stir at 30°C and 100 r / min for 40 min. Dry the fiber and cure it at 100°C for 30 min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber.
[0021] Comparative Example 1: The only difference from Example 2 is step (2), which changes "weigh soluble chitosan and thiourea at a mass ratio of 1:1.3" to "weigh soluble chitosan and thiourea at a mass ratio of 1:1".
[0022] Comparative Example 2: The only difference from Example 2 is step (2), where “weigh soluble chitosan and thiourea at a mass ratio of 1:1.3” is changed to “weigh soluble chitosan and thiourea at a mass ratio of 1:1.1”.
[0023] Comparative Example 3: The only difference from Example 2 is the step (2), where “weigh soluble chitosan and thiourea at a mass ratio of 1:1.3” is changed to “weigh soluble chitosan and thiourea at a mass ratio of 1:1.2”.
[0024] Comparative Example 4: The only difference from Example 2 is the step (2), where “weigh soluble chitosan and thiourea at a mass ratio of 1:1.3” is changed to “weigh soluble chitosan and thiourea at a mass ratio of 1:1.4”.
[0025] Comparative Example 5: The only difference from Example 2 is the step (2), where “weigh soluble chitosan and thiourea at a mass ratio of 1:1.3” is changed to “weigh soluble chitosan and thiourea at a mass ratio of 1:1.5”.
[0026] Comparative Example 6: The only difference from Example 2 is the difference in step (2). In step (2), "dissolve thiourea at 40 wt% in 6M hydrochloric acid aqueous solution and add it dropwise to chitosan solution at 30°C and 400 r / min with stirring, adjust the pH to 5 with 0.1M acetic acid, and continue stirring for 20 min to obtain a mixed solution", the phrase "adjust the pH to 5 with 0.1M acetic acid" is changed to "adjust the pH to 4 with 0.1M acetic acid".
[0027] Comparative Example 7: The only difference from Example 2 is step (2), where “adjusting pH to 5 with 0.1M acetic acid” is changed to “adjusting pH to 4.5 with 0.1M acetic acid”.
[0028] Comparative Example 8: The only difference from Example 2 is step (2), where “adjust pH to 5 with 0.1M acetic acid” is changed to “adjust pH to 5.5 with 0.1M acetic acid”.
[0029] Comparative Example 9: The only difference from Example 2 is the difference in step (2). In step (2), the phrase "place the mixed solution into a microwave reactor, reflux at 640W for 7 min, cool, adjust the pH to 8 with 1M sodium hydroxide, precipitate with ethanol, wash, and obtain thiolized chitosan" is changed to "reflux at 640W for 4 min".
[0030] Comparative Example 10: The only difference from Example 2 is step (2), where “reflux at 640W for 7 minutes” is changed to “reflux at 640W for 5 minutes”.
[0031] Comparative Example 11: The only difference from Example 2 is step (2), where “reflux at 640W for 7 minutes” is changed to “reflux at 640W for 6 minutes”.
[0032] Comparative Example 12: The only difference from Example 2 is step (2), where “reflux at 640W for 7 minutes” is changed to “reflux at 640W for 8 minutes”.
[0033] Comparative Example 13: The only difference from Example 2 is the step (2), where “add 0.05 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan” is changed to “add 0.005 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan”.
[0034] Comparative Example 14: The only difference from Example 2 is step (2), which changes "add 0.05 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan" to "add 0.01 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan".
[0035] Comparative Example 15: The only difference from Example 2 is the step (2), where “add 0.05 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan” is changed to “add 0.03 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan”.
[0036] Comparative Example 16: The only difference from Example 2 is step (2), which changes "add 0.05 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan" to "add 0.1 times the amount of nano zinc oxide powder based on the mass of thiolized chitosan".
[0037] Comparative Example 17: A method for preparing an anti-ultraviolet and anti-aging fiber mainly includes the following preparation steps: (1) In a nitrogen atmosphere, 1,3-propanediol, terephthalic acid and zirconium acetylacetonate were mixed evenly in a molar ratio of 1:1:0.0002, stirred at 180°C and 300 r / min for 4 h, then heated to 220°C, and the reaction vacuum was kept below 100 Pa. Stirring was continued for 6 h to obtain polyester; the polyester was melt-spun into polyester fiber. (2) Chitosan was dispersed in deionized water at 20 wt%, stirred at 50 °C and 300 r / min for 1.5 h, 7 wt% hydrogen peroxide was added to the system, the temperature was raised to 70 °C and stirred for 3 h, filtered, and precipitated with anhydrous ethanol to obtain soluble chitosan; soluble chitosan and thiourea were weighed at a mass ratio of 1:1.3, and soluble chitosan was dissolved in 1% acetic acid solution at 2 wt% to obtain chitosan solution; thiourea was dissolved in 6M hydrochloric acid aqueous solution at 35 wt%, and added dropwise to the chitosan solution at 27 °C and 300 r / min with stirring. In the solution, the pH was adjusted to 5 with 0.1M acetic acid, and stirring was continued for 15 min to obtain a mixed solution. The mixed solution was placed in a microwave reactor and refluxed at 640W for 7 min. After cooling, the pH was adjusted to 8 with 1M sodium hydroxide, ethanol was used for precipitation, and the solution was washed to obtain thiolized chitosan. The thiolized chitosan was dissolved at 2 wt% in 1% acetic acid solution, and 0.05 times the mass of nano zinc oxide powder was added according to the mass of thiolized chitosan. The mixture was stirred at 25℃ and 650 r / min for 6 h, ethanol was used for precipitation, and the solution was washed to obtain zinc oxide-loaded thiolized chitosan. (3) Weigh zinc oxide-thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:0.5:0.8. Dissolve the zinc oxide-thiolized chitosan in 1% acetic acid solution at 1.5 wt%. Add sodium acetate and malic acid to the solution and stir at 27°C and 300 r / min for 20 min to obtain zinc oxide-thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-thiolized chitosan solution and stir at 27°C and 75 r / min for 30 min. Dry the fiber and cure it at 90°C for 20 min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber.
[0038] Comparative Example 18: A method for preparing an anti-ultraviolet and anti-aging fiber mainly includes the following preparation steps: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine and triethylamine in a molar ratio of 1:1.3:0.1:1.8. Dissolve methyl ferulic acid in anhydrous pyridine at 13 wt%. Add 4-dimethylpyridine, triethylamine and succinic anhydride under stirring at 27 °C and 300 r / min. Continue stirring for 6 h. Precipitate in ice water, wash, and obtain methyl ferulic acid succinic acid monoester. Weigh 1,3-propanediol in a molar ratio of 1:0.8:0.25:0.0002. 1,3-Propanediol, methyl ferulic acid succinate monoester, and zirconium acetylacetonate were mixed and reacted at 180°C and 300 rpm for 1.5 h with stirring. Then, terephthalic acid was added, and stirring was continued for 2.5 h. The temperature was raised to 220°C, and the reaction vacuum was kept below 100 Pa. Stirring was continued for 6 h to obtain UV-protective modified polyester. The UV-protective modified polyester was melt-spun into UV-protective polyester fibers. (2) Chitosan was dispersed in deionized water at 20 wt%, stirred at 300 r / min for 1.5 h at 50 °C, 7 wt% hydrogen peroxide was added to the system, the temperature was raised to 70 °C and stirred for 3 h, filtered and precipitated with anhydrous ethanol to obtain soluble chitosan; soluble chitosan was dissolved in 1% acetic acid solution at 2 wt%, 0.05 times the weight of nano zinc oxide powder was added according to the chitosan mass, stirred at 650 r / min for 6 h at 25 °C, precipitated with ethanol, washed, and zinc oxide-loaded chitosan was obtained; (3) Weigh zinc oxide-thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:0.5:0.8. Dissolve the zinc oxide-thiolized chitosan in 1% acetic acid solution at 1.5 wt%. Add sodium acetate and malic acid to the solution and stir at 27°C and 300 r / min for 20 min to obtain zinc oxide-thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-thiolized chitosan solution and stir at 27°C and 75 r / min for 30 min. Dry the fiber and cure it at 90°C for 20 min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber.
[0039] Comparative Example 19: A method for preparing an anti-ultraviolet and anti-aging fiber mainly includes the following preparation steps: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine and triethylamine in a molar ratio of 1:1.3:0.1:1.8. Dissolve methyl ferulic acid in anhydrous pyridine at 13 wt%. Add 4-dimethylpyridine, triethylamine and succinic anhydride under stirring at 27 °C and 300 r / min. Continue stirring for 6 h. Precipitate in ice water, wash, and obtain methyl ferulic acid succinic acid monoester. Weigh 1,3-propanediol in a molar ratio of 1:0.8:0.25:0.0002. 1,3-Propanediol, methyl ferulic acid succinate monoester, and zirconium acetylacetonate were mixed and reacted at 180°C and 300 rpm for 1.5 h with stirring. Then, terephthalic acid was added, and stirring was continued for 2.5 h. The temperature was raised to 220°C, and the reaction vacuum was kept below 100 Pa. Stirring was continued for 6 h to obtain UV-protective modified polyester. The UV-protective modified polyester was melt-spun into UV-protective polyester fibers. (2) Chitosan was dispersed in deionized water at 20 wt%, stirred at 50 °C and 300 r / min for 1.5 h, 7 wt% hydrogen peroxide was added to the system, the temperature was raised to 70 °C and stirred for 3 h, filtered and precipitated with anhydrous ethanol to obtain soluble chitosan; soluble chitosan and thiourea were weighed at a mass ratio of 1:1.3, soluble chitosan was dissolved in 1% acetic acid solution at 2 wt% to obtain chitosan solution; thiourea was dissolved in 6M hydrochloric acid aqueous solution at 35 wt%, and added dropwise to chitosan solution at 27 °C and 300 r / min with stirring, the pH was adjusted to 5 with 0.1M acetic acid, and stirring was continued for 15 min to obtain mixed solution; the mixed solution was placed in a microwave reactor, refluxed at 640 W for 7 min, cooled, the pH was adjusted to 8 with 1M sodium hydroxide, precipitated with ethanol, washed, and thiolized chitosan was obtained; (3) Weigh zinc oxide-thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:0.5:0.8. Dissolve the zinc oxide-thiolized chitosan in 1% acetic acid solution at 1.5 wt%. Add sodium acetate and malic acid to the solution and stir at 27°C and 300 r / min for 20 min to obtain zinc oxide-thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-thiolized chitosan solution and stir at 27°C and 75 r / min for 30 min. Dry the fiber and cure it at 90°C for 20 min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber.
[0040] Comparative Example 20: A method for preparing an anti-ultraviolet and anti-aging fiber mainly includes the following preparation steps: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine and triethylamine in a molar ratio of 1:1.3:0.1:1.8. Dissolve methyl ferulic acid in anhydrous pyridine at 13 wt%. Add 4-dimethylpyridine, triethylamine and succinic anhydride under stirring at 27 °C and 300 r / min. Continue stirring for 6 h. Precipitate in ice water, wash, and obtain methyl ferulic acid succinic acid monoester. Weigh 1,3-propanediol in a molar ratio of 1:0.8:0.25:0.0002. 1,3-Propanediol, methyl ferulic acid succinate monoester, and zirconium acetylacetonate were mixed and reacted at 180°C and 300 rpm for 1.5 h with stirring. Then, terephthalic acid was added, and stirring was continued for 2.5 h. The temperature was raised to 220°C, and the reaction vacuum was kept below 100 Pa. Stirring was continued for 6 h to obtain UV-protective modified polyester. The UV-protective modified polyester was melt-spun into UV-protective polyester fibers. (2) Chitosan was dispersed in deionized water at 20 wt%, stirred at 50 °C and 300 r / min for 1.5 h, 7 wt% hydrogen peroxide was added to the system, the temperature was raised to 70 °C and stirred for 3 h, filtered, and precipitated with anhydrous ethanol to obtain soluble chitosan; soluble chitosan and thiourea were weighed at a mass ratio of 1:1.3, and soluble chitosan was dissolved in 1% acetic acid solution at 2 wt% to obtain chitosan solution; thiourea was dissolved in 6M hydrochloric acid aqueous solution at 35 wt%, and added dropwise to the chitosan solution at 27 °C and 300 r / min with stirring. In the solution, the pH was adjusted to 5 with 0.1M acetic acid, and stirring was continued for 15 min to obtain a mixed solution. The mixed solution was placed in a microwave reactor and refluxed at 640W for 7 min. After cooling, the pH was adjusted to 8 with 1M sodium hydroxide, ethanol was used for precipitation, and the solution was washed to obtain thiolized chitosan. The thiolized chitosan was dissolved at 2 wt% in 1% acetic acid solution, and 0.05 times the mass of nano zinc oxide powder was added according to the mass of thiolized chitosan. The mixture was stirred at 25℃ and 650 r / min for 6 h, ethanol was used for precipitation, and the solution was washed to obtain zinc oxide-loaded thiolized chitosan. (3) Weigh zinc oxide-thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:0.5:0.8. Dissolve the zinc oxide-thiolized chitosan in 1% acetic acid solution at 1.5 wt%. Add sodium acetate and malic acid to the solution and stir at 27°C and 300 r / min for 20 min to obtain zinc oxide-thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-thiolized chitosan solution and stir at 27°C and 75 r / min for 30 min. Dry the fiber and cure it at 90°C for 20 min in a nitrogen atmosphere to obtain UV-resistant and anti-aging fiber.
[0041] Experimental Example 1: Determination of optimal conditions for thiourea-modified chitosan (thiourea dosage, pH, and treatment time) Test Method: The content of free thiol groups was analyzed using the Ellman method. The mercapto-chitosan sample was dissolved in 0.5 mM phosphate buffer (pH 8.0) to prepare a sample solution. 5,5'-dithiobis(2-nitrobenzoic acid) was dissolved at 0.03 wt% in 0.5 mM phosphate buffer (pH 8.0) to prepare the Ellman reagent working solution. L-cysteine was used as a standard, diluted with the same buffer to prepare a series of standard solutions with concentrations of 0, 0.025, 0.05, 0.1, 0.15, and 0.2 mM. Appropriate amounts of each standard solution and the sample solution were sequentially reacted with an equal volume of Ellman reagent working solution at room temperature in the dark for 15–30 min. The absorbance at 412 nm was measured using a UV-Vis spectrophotometer. The L-cysteine standard was used to establish a standard curve. The results are shown in Table 1.
[0042] Table 1
[0043] A comparison of Example 2 with Comparative Examples 1-5 reveals that the amount of thiourea added significantly affects the thiol content of the final product. When the amount of thiourea added is insufficient, its concentration as a nucleophile and sulfur source is low, making it unable to effectively undergo nucleophilic substitution with the 6-OH site on the chitosan molecular chain, resulting in a low degree of substitution and low thiol content. However, when the amount of thiourea added is too high, under the intense reaction environment of strong acidity and microwave heating, excessive thiourea molecules and newly generated thiol groups undergo violent oxidative coupling side reactions, generating a large number of stable disulfide bonds. At the same time, the high concentration of acidic environment may also lead to partial degradation of the chitosan molecular chain. These factors together consume the target free thiol groups, resulting in a decrease in the final measured effective thiol content. Through experimental optimization, it was determined that when the mass ratio of thiourea to soluble chitosan is 1.3:1, the nucleophilic substitution reaction and oxidative side reactions reach the optimal balance. At this point, the substitution efficiency of the 6-OH site is the highest, and the obtained free thiol content also reaches its peak.
[0044] By comparing Example 2 with Comparative Examples 6-8, it was found that when the pH value is below 5, the excessively acidic environment accelerates the decomposition of thiourea and promotes the violent oxidative coupling of newly generated thiol groups, resulting in a large number of disulfide bonds and the consumption of effective free thiol groups. When the pH value is above 5, the protonation degree of amino groups on the chitosan molecular chain decreases, and the number of free amino groups increases. These amino groups compete with the 6-OH site for thiourea reagent, resulting in side reactions that generate thiourea derivatives and weaken the specific substitution efficiency for the 6-OH site. Through experimental optimization, it was determined that when the pH value of the system is precisely controlled at 5, the stability and reactivity of the thiourea reagent can be guaranteed, while the competitive side reactions of amino groups and the oxidation of thiol groups can be suppressed to the maximum extent.
[0045] By comparing Example 2 with Comparative Examples 9-12, it can be found that the effect of microwave treatment time on thiol content shows a trend of first increasing and then decreasing. When the microwave time is too short, the energy input is insufficient, which cannot effectively activate the 6-OH sites on the chitosan molecular chain and drive the nucleophilic substitution reaction of thiourea, resulting in an incomplete substitution reaction and a low thiol content. However, when the microwave time is too long, the excessive thermal effect will aggravate the intensity of the reaction system. On the one hand, the newly generated thiols are rapidly oxidized to form disulfide bonds, and on the other hand, the glycosidic bonds of the chitosan molecular chain may be broken and degraded, thereby consuming the successfully introduced thiols and destroying the molecular structure of the product. Therefore, the optimal treatment time is controlled at 7 min.
[0046] Therefore, the optimal selection was to add 1.3 times the mass of chitosan, set the pH to 5, and set the reaction time to 7 min, which are the reaction conditions of Example 2.
[0047] Experimental Example 2: Determination of the optimal addition amount of nano zinc oxide powder Test method: Determined by UV protection performance. UV-protective and anti-aging polyester fibers were twisted to 1000 twists / m on a twisting machine, resulting in yarn with a linear density of 18.5 tex. The yarn was then woven into a fabric sample using a 12-gauge / 25.4mm computerized flat knitting machine with a plain weave structure. The fabric surface density was 165.2 ± 2.5 g / m². 2 The thickness was 0.63±0.08mm. The UV protection performance of the fabric was tested using an SPF-290AS UV protection performance tester according to standard GB / T17032—1997 "Test Method for Ultraviolet Transmittance of Textile Fabrics". The results are shown in Table 2.
[0048] Table 2
[0049] A comparison of Example 2 with Comparative Examples 13-16 reveals that the amount of nano-zinc oxide powder added significantly affects the UV protection performance of the fibers. When the amount added is low, the loading of nano-zinc oxide on the surface of the thiolized chitosan is insufficient, resulting in limited reflection and scattering of ultraviolet rays and a negligible improvement in UV protection performance. Conversely, when the amount added is excessive, the nano-zinc oxide particles are prone to agglomeration, which reduces their specific surface area and dispersion uniformity, affecting film formation and coverage on the fiber surface. Furthermore, excessively large agglomerates may cause local structural defects, making it easier for ultraviolet rays to penetrate, thus reducing UV protection performance. Therefore, the amount of nano-zinc oxide added was chosen to be 0.05 times the mass of the thiolized chitosan.
[0050] Experimental Example 3: UV protection performance, anti-aging performance, and antibacterial performance tests The UV-protective and anti-aging fibers obtained in each embodiment were combined with the fibers of Comparative Examples 17-20. The UV-protective and anti-aging polyester fibers were twisted on a twisting machine to a yarn density of 1000 twists / m and 18.5 tex. The yarn was then woven into a fabric sample using a 12-needle / 25.4mm computerized flat knitting machine with a plain weave structure. The fabric surface density was 165.2 ± 2.5 g / m². 2 The thickness is 0.63±0.08mm.
[0051] UV protection performance test method: According to GB / T17032—1997 "Test method for UV transmittance of textile fabrics", the UV protection performance of the fabric is tested using an SPF-290AS UV protection performance tester.
[0052] Anti-aging performance test method: The fabric was subjected to accelerated aging treatment using a PT2030B accelerated aging instrument. The UV light source of the aging instrument was a 300W UV bulb, and the heating was carried out by hot air circulation at a temperature of 70℃ for 3 hours. The tensile strength of the fabric before and after aging was tested according to GB / T3923.1—2013 "Textiles - Tensile Properties of Fabrics - Part 1" at a tensile speed of 100mm / min, and the breaking strength retention rate was calculated.
[0053] Tensile strength retention rate (%) = (average tensile strength of the fabric after aging / average tensile strength of the fabric before aging) × 100%.
[0054] Antimicrobial performance test method: According to the AATCC100-2004 test method, Escherichia coli (ATCC43895) and Staphylococcus aureus (ATCC6538) were selected for antimicrobial performance testing of fabrics, and the antimicrobial effect was evaluated by counting the number of colonies.
[0055] The results are shown in Table 3.
[0056] Table 3
[0057] A comparison of the experimental data from Examples 1-3 and Comparative Examples 17-20 in Table 3 reveals that the UV-protective and anti-aging fibers prepared by this invention have excellent UV protection, anti-aging, and antibacterial properties.
[0058] A comparison of Examples 1-3 and Comparative Example 17 reveals that incorporating the UV-protective intermediate into the polyester molecular backbone via copolymerization plays a decisive role in the fiber's UV protection and anti-aging properties. This is because the cinnamic acid ester structure within the intermediate molecule forms a conjugated system with strong UV absorption capabilities. Through covalent bonds, it directly becomes part of the polymer backbone, preventing the migration and loss of small-molecule additives during subsequent processing and use, thus endowing the fiber with a durable and stable UV shielding function. Simultaneously, this conjugated structure effectively absorbs high-energy UV photons and releases them as harmless heat, significantly reducing the degree of UV-induced photo-oxidative degradation of the polyester molecular chain. This fundamentally slows down the aging process of the material, enabling fabrics woven from this fiber to possess both excellent durable UV protection and anti-aging properties.
[0059] A comparison of Examples 1-3 and Comparative Example 18 reveals that thiolation of chitosan is a key step in improving the anti-aging properties of fibers. This is because the treatment introduces a large number of highly reducing free thiol groups into the chitosan molecular chain. These active groups can efficiently capture free radicals generated during UV irradiation and use, interrupting the free radical chain reaction and thus effectively inhibiting the oxidative degradation of the polyester fiber matrix. At the same time, the thiolated chitosan and nano zinc oxide form a stable complex through coordination, further enhancing the stability of the functional layer. Through a synergistic effect, the overall UV absorption and scattering capabilities are improved, so that the protective layer formed on the fiber surface not only has excellent and long-lasting antioxidant function, but also effectively blocks the direct damage of UV light to the fiber body.
[0060] A comparison of Examples 1-3 and Comparative Example 19 reveals that loading nano-zinc oxide into thiolized chitosan synergistically enhances the UV protection and antibacterial properties of the fiber. This is because the nano-zinc oxide particles can effectively block ultraviolet rays through a dual mechanism of physical scattering and absorption, complementing the UV absorption function of the UV-protective polyester matrix, significantly broadening the UV protection band and improving shielding efficiency. Simultaneously, under light conditions, nano-zinc oxide can activate and generate reactive oxygen free radicals and continuously release zinc ions. These active ingredients can penetrate bacterial cell walls, disrupting their internal protein structure and metabolic functions.
[0061] By comparing Examples 1-3 and Comparative Example 20, it can be found that alkaline treatment of polyester fibers can partially hydrolyze the ester bonds on their surface to generate hydrophilic polar groups such as hydroxyl and carboxyl groups. During the subsequent curing process at 90°C in a nitrogen atmosphere, these surface carboxyl groups undergo efficient amidation condensation reactions with the abundant amino groups on the thiolized chitosan molecular chains, forming a strong covalent bond between the fiber substrate and the functional coating. This strong chemical bond fundamentally prevents the functional coating from physically detaching during subsequent textile processing or washing, ensuring that functional components such as UV absorption, anti-oxidation, and antibacterial nano-zinc oxide are permanently and stably anchored on the fiber surface, thereby enhancing the fabric's UV protection, anti-aging, and antibacterial properties.
[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention 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 the present invention.
Claims
1. A UV-protective and anti-aging fiber, characterized in that, The UV-protective and anti-aging fiber is obtained by impregnating UV-protective polyester fiber with an alkali-treated solution of zinc oxide-thiolized chitosan, followed by drying and curing.
2. The UV-resistant and anti-aging fiber according to claim 1, characterized in that, The UV-protective polyester fiber is obtained by melt spinning after polycondensation reaction of UV-protective intermediate with 1,3-propanediol and terephthalic acid.
3. The UV-resistant and anti-aging fiber according to claim 2, characterized in that, The UV-protective intermediate is prepared by esterification of methyl ferulic acid and succinic anhydride followed by hydrolysis and acidification.
4. The UV-resistant and anti-aging fiber according to claim 1, characterized in that, The zinc oxide-loaded thiolized chitosan is prepared by degrading and thiolizing chitosan and then loading it with nano-zinc oxide.
5. A method for preparing an anti-ultraviolet and anti-aging fiber, characterized in that, The preparation steps include the following: (1) Weigh methyl ferulic acid, succinic anhydride, 4-dimethylpyridine, and triethylamine in a molar ratio of 1:(1.05~1.5):(0.05~0.15):(1.5~2). Dissolve methyl ferulic acid in anhydrous pyridine at 10~15wt%. Add 4-dimethylpyridine, triethylamine, and succinic anhydride at 25~30℃ and react for 4~8h to obtain methyl ferulic acid succinic acid monoester; in a molar ratio of 1:(0.65~0.90): (0.15~0.35):(0.0001~0.0003) Weigh 1,3-propanediol, terephthalic acid, methyl ferulic acid succinate monoester and zirconium acetylacetonate. Mix 1,3-propanediol, methyl ferulic acid succinate monoester and zirconium acetylacetonate, and react at 160~200℃ for 1~2h. Add terephthalic acid and continue the reaction for 2~3h. Raise the temperature to 200~240℃ and continue the reaction for 4~7h to obtain UV-resistant modified polyester. UV-protective modified polyester is melt-spun into UV-protective polyester fiber; (2) Disperse chitosan at 15-25 wt% in deionized water, add 6-8 wt% hydrogen peroxide to the system, and react at 60-80℃ for 2-4 h to obtain soluble chitosan; weigh soluble chitosan and thiourea at a mass ratio of 1:1-1.5, dissolve soluble chitosan at 1.5-2.5 wt% in 1% acetic acid solution to obtain chitosan solution; dissolve thiourea at 30-40 wt% in 6M hydrochloric acid aqueous solution, and add it dropwise to the chitosan solution at 25-30℃. In a sugar solution, the pH is adjusted to 4-5.5 with 0.1M acetic acid, and the reaction is carried out for 10-20 minutes to obtain a mixed solution. The mixed solution is placed in a microwave reactor and refluxed at 640W for 4-8 minutes to obtain thiolized chitosan. The thiolized chitosan is dissolved in 1% acetic acid solution at 1.5-2.5 wt%, and 0.005-0.1 times the mass of nano zinc oxide powder is added according to the mass of thiolized chitosan. The reaction is carried out at 20-30℃ to obtain zinc oxide-loaded thiolized chitosan. (3) Weigh zinc oxide-loaded thiolized chitosan, sodium acetate and malic acid in a mass ratio of 1:(0.45~0.55):(0.75~0.
85. Dissolve the zinc oxide-loaded thiolized chitosan in 1% acetic acid solution at 1~2wt%. Add sodium acetate and malic acid to the solution to obtain a zinc oxide-loaded thiolized chitosan solution. Impregnate the alkali-treated UV-resistant polyester fiber in the zinc oxide-loaded thiolized chitosan solution, stir at 25~30℃ for 20~40min, dry, and cure at 80~100℃ for 10~30min to obtain UV-resistant and anti-aging fiber.
6. The method for preparing an anti-ultraviolet and anti-aging fiber according to claim 5, characterized in that, The key process parameters for melt spinning in step (1) are as follows: spinning temperature 260~280℃, screw speed 35~45r / min, side blowing speed 0.5~0.7m / s, first drafting roller speed 1860~1980m / min, second drafting roller speed 4800~4850m / min, winding speed 4745~4800m / min, and draw ratio 2.
58.
7. The method for preparing an anti-ultraviolet and anti-aging fiber according to claim 5, characterized in that, The degree of deacetylation of the chitosan in step (2) is 90%, and the molecular weight is 10~20kDa; the purity of the nano zinc oxide powder is 99.9%, and the average particle size is 30nm.
8. The method for preparing an anti-ultraviolet and anti-aging fiber according to claim 5, characterized in that, The alkali treatment method for the UV-resistant polyester fiber described in step (3) is as follows: Sodium hydroxide, hexadecyltrimethylammonium bromide and deionized water are mixed and dissolved in a volume ratio of 1:(0.15~5):(900~1000) to obtain an alkali treatment solution. The UV-resistant polyester fiber is immersed in the alkali treatment solution and treated at 90°C for 1 hour. After washing with water, it is dried for later use.