Preparation method and application of anti-ultraviolet finishing liquid based on composite nano material

Abstract

The invention discloses a preparation method and application of an anti-ultraviolet finishing liquid based on a composite nano material. The preparation method comprises the following steps: dissolving tannic acid in water to form a tannic acid aqueous solution; and sequentially adding nano TiO2, cellulose nanofibers, a dispersing agent and a waterborne polyurethane adhesive, and carrying out high-speed shearing to form a uniform suspension, thereby obtaining the anti-ultraviolet finishing liquid. When the finishing liquid is applied to the silk fabric, the adhesive is cross-linked and cured by adopting a twice-dipping twice-rolling, pre-drying and baking process. Through the triple synergistic effect of nano TiO2 (UVA shielding), cellulose nanofiber (UVB shielding) and tannic acid (oxidation resistance), the silk fabric is endowed with efficient and lasting anti-ultraviolet performance (UPF > 200), meanwhile, the washing resistance is remarkably improved, the original air permeability and hand feeling of the fabric are kept, and the silk fabric is suitable for development of high-grade outdoor functional textiles.

Description

Technical Field

[0001] This invention belongs to the field of functional finishing technology of textiles, specifically relating to a method for preparing an anti-UV finishing liquid based on composite nanomaterials and its application. Background Technology

[0002] Silk fabrics are widely used due to their natural skin-friendliness and breathability, but their ultraviolet protection performance (UPF value) is generally below 15, making it difficult to meet the needs of outdoor protection. Existing anti-ultraviolet finishing technologies mainly rely on organic ultraviolet absorbers (such as benzotriazoles) or nano metal oxides (such as TiO2 and ZnO), but they have the following drawbacks: (1) Organic absorbers: poor washability, risk of chemical residue, and easy decomposition and failure at high temperatures; (2) Nanomaterials: easy agglomeration leading to uneven dispersion, affecting UPF value and fabric feel; (3) Adhesive compatibility: traditional adhesives (such as acrylics) have weak bonding with silk fabrics, resulting in poor washability and breathability.

[0003] Chinese patent application CN114395917A (publication date: April 26, 2022) discloses a nano-ceramic boron-titanium anti-UV polyester-cotton fiber fabric, comprising the following steps: S1. Hydrophilic modification of the fabric surface; after washing the polyester-cotton fiber fabric, it is treated in a plasma treatment machine, and then the treated fabric is pretreated in a chitosan solution for later use; S2. Boron grafting modification: tannic acid and 1,4- Terephthalic acid was added to a tetrahydrofuran solution, and the polyester-cotton fiber fabric was placed in the boron grafting solution to carry out a grafting reaction, thereby obtaining a boron-grafted modified polyester-cotton fiber fabric; S3. Titanium dioxide sol modification: Tetrabutyl titanate, acetic acid and ethanol were uniformly mixed, and hydrochloric acid aqueous solution was added dropwise to the mixture of tetrabutyl titanate, acetic acid and ethanol to obtain a homogeneous and stable sol; S4. Polyester-cotton fabric finishing: The polyester-cotton fabric was treated with sol to obtain a nano-ceramic boron-titanium anti-UV polyester-cotton fiber fabric.

[0004] This invention achieves its UV protection effect through the synergistic effect of tannic acid and titanium dioxide.

[0005] Chinese patent application CN120211115A (publication date: June 27, 2025) discloses an anti-UV finishing agent and method for silk fabrics. The finishing agent involves first preparing chalcone-Schiff base modified chitosan, then preparing a titanium dioxide-grafted chalcone-Schiff base chitosan, and finally obtaining a finishing agent consisting of chalcone-Schiff base modified titanium dioxide grafted chitosan. This finishing method utilizes the synergistic effect of chalcone-modified chitosan and titanium dioxide, not only solving the shortcomings of current single antibacterial finishing agents in use, but also addressing the problem of silk fabrics being prone to photoembrittlement under prolonged UV exposure.

[0006] Chinese patent application CN119287655A (publication date: January 10, 2025) discloses a bio-based UV-resistant finishing agent and its preparation method, comprising the following steps: (1) adding a UV absorber and / or a UV shielding agent to a solvent and ultrasonically dispersing them to obtain a dispersion; (2) adding cellulose nanofibers to the dispersion and stirring at 30-70°C for 2-6 hours to obtain the biotin-based UV-resistant finishing agent; the aspect ratio of the cellulose nanofibers is 10010000. This invention effectively protects the dye chromophores and polymer segments on fabrics through a simple coating finishing process, significantly improving the fabric's resistance to sunlight and strength retention under high-intensity UV radiation outdoors.

[0007] Based on the above-mentioned existing technology search and analysis, it is evident that although many patents currently involve UV-resistant finishing, most have not addressed the issues of breathability, hand feel, and durability of silk fabrics, and few solutions synergistically utilize nano-TiO2, cellulose nanofibers (CNF), and tannic acid. Therefore, developing a UV-resistant finishing solution that is stable in dispersion, environmentally friendly, highly efficient, and firmly bonded to silk fibers is of significant practical importance. Summary of the Invention

[0008] To address the above technical problems, this invention provides a method for preparing an anti-UV finishing liquid based on composite nanomaterials, comprising the following steps: Step S1: Dissolve tannic acid in water according to the ratio to obtain an aqueous solution of tannic acid; Step S2: Add nano-TiO2, cellulose nanofibers, dispersant, and water-based polyurethane binder to the tannic acid aqueous solution according to the proportion to obtain a mixed solution; Step S3: The mixed solution described in S2 is sheared at high speed until a uniform suspension is formed, to obtain a functionally compounded UV-resistant finishing solution.

[0009] Furthermore, the water mentioned in step S1 is deionized water.

[0010] Furthermore, the dispersant mentioned in step S2 is SW-996.

[0011] Furthermore, in step S3, the high-speed shearing speed is 7000-9000 rpm, and the time is 3-8 min.

[0012] Furthermore, in step S3, the high-speed shearing speed is 8000 rpm and the time is 5 min.

[0013] Furthermore, the content of tannic acid in the UV-resistant finishing solution in step S3 is 1wt% to 5wt%.

[0014] Furthermore, in step S3, the content of nano-TiO2 in the UV-resistant finishing liquid is 2wt% to 5wt%, the content of cellulose nanofibers is 2wt% to 7wt%, the content of dispersant is 0.2wt% to 1.5wt%, and the content of waterborne polyurethane adhesive is 1wt% to 6wt%.

[0015] Furthermore, the content of tannic acid in the UV-resistant finishing solution in step S3 is 3wt% to 5wt%.

[0016] Furthermore, in step S3, the content of the nano-TiO2 in the UV-resistant finishing liquid is 3wt%, the content of the cellulose nanofiber is 5wt%, the content of the dispersant is 0.5wt%, and the content of the waterborne polyurethane adhesive is 2wt%.

[0017] The present invention also provides the application of the UV-resistant finishing solution in the preparation of washable UV-resistant silk fabrics.

[0018] This invention also provides a method for preparing washable UV-resistant silk fabric using the aforementioned UV-resistant finishing solution, comprising the following steps: Step 1: Padding: The silk fabric is dipped and paved twice in the sol; Step 2: Pre-drying: Dry the silk fabric obtained in Step 1 at a temperature of 70℃~80℃ for 2~3 minutes; Step 3: Baking: Bake the silk fabric obtained in Step 2 at a temperature of 120℃~130℃ for 2~3 minutes to allow the adhesive to crosslink and cure.

[0019] Furthermore, in step 1, the liquid yield is 80% and the liquor ratio is 1:20.

[0020] Compared with the prior art, the advantages and effects of the present invention are as follows: 1. This invention has excellent synergistic UV protection performance. Through the triple protection mechanism of cellulose nanofibers (UVB shielding), nano TiO2 (UVA shielding), and tannic acid (antioxidant), it achieves full-band UV shielding with a UPF value that far exceeds the standard requirement (>50), reaching up to 480 or more.

[0021] 2. The durability of this invention is significantly improved. It uses a water-based polyurethane adhesive to enhance the bonding strength between nanoparticles and silk fibers. After 50 washes, the UPF value still remains above 200, demonstrating excellent wash resistance.

[0022] 3. The comfort of the fabric is preserved in this invention. The air permeability of the treated silk fabric can be controlled within 2%-15%. The hand feel is considered by more than 90% of blind tests to be no significantly different from the untreated fabric, perfectly preserving the original characteristics of silk.

[0023] 4. This invention is environmentally friendly and simple to process. It uses water as a solvent and bio-based materials (cellulose nanofibers, tannic acid). The preparation process does not require complex modification. High-speed shearing can achieve uniform dispersion, making it suitable for large-scale production.

[0024] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0025] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0027] in: Figure 1 This is a flowchart illustrating the preparation method of the UV-resistant finishing liquid based on composite nanomaterials in this application; Figure 2 These are SEM images of the silk fabrics in Experiment 1 of this application before and after UV-resistant finishing. Figure 2 (a) SEM image of the silk fabric in Experimental Group 1 of this application before UV-resistant finishing; Figure 2 (b) SEM image of the silk fabric after UV-resistant finishing in Experimental Group 1 of this application; Figure 3 These are SEM images of the silk fabrics in Experiment 2 of this application before and after UV-resistant finishing. Figure 3 (a) SEM image of the silk fabric in Experimental Group 2 of this application before UV-resistant finishing; Figure 3 (b) SEM images of the silk fabrics in Experimental Group 2 of this application after UV-resistant finishing; Figure 4 These are SEM images of the silk fabrics in Experiment 3 of this application before and after UV-resistant finishing. Figure 4(a) SEM image of the silk fabric in experimental group 3 of this application before UV-resistant finishing; Figure 4 (b) SEM images of the silk fabrics in experimental group 3 of this application after UV-resistant finishing; Figure 5 These are SEM images of the silk fabrics in Experiment 4 of this application before and after UV-resistant finishing. Figure 5 (a) SEM image of the silk fabric in experimental group 4 of this application before UV-resistant finishing; Figure 5 (b) SEM images of the silk fabrics in experimental group 4 of this application after UV-resistant finishing; Figure 6 These are SEM images of the silk fabrics in Experiment 5 of this application before and after UV-resistant finishing. Figure 6 (a) SEM image of the silk fabric in experimental group 5 of this application before UV-resistant finishing; Figure 6 (b) SEM images of the silk fabrics in experimental group 5 of this application after UV-resistant finishing; Figure 7 The graph shows the ultraviolet-induced test results of silk fabrics in the control group and experimental groups 1-5 of this application; Figure 7 (a) is a graph showing the UV-induced test results for the control group; Figure 7 (b) is a graph showing the ultraviolet-induced test results of experimental group 1; Figure 7 (c) is a graph showing the ultraviolet-induced test results of experimental group 2; Figure 7 (d) is a graph showing the ultraviolet-induced test results of experimental group 3; Figure 7 (e) is a graph showing the results of the ultraviolet-induced test in experimental group 4; Figure 7 (f) shows the results of the ultraviolet-induced test in experimental group 5; Figure 8 Scanning electron microscope images of tannic acid, cellulose nanofibers and nano-TiO2 in this application; Figure 8 (a) is a scanning electron microscope image of tannic acid; Figure 8 (b) is a scanning electron microscope image of cellulose nanofibers; Figure 8 (c) shows a SEM image of titanium dioxide (TiO2); Figure 9 These are scanning electron microscope images of the freeze-dried UV-resistant finishing solutions used in this application. Figure 9 (a) is a scanning electron microscope image of freeze-dried experimental group 1; Figure 9 (b) is a scanning electron microscope image of freeze-dried samples from experimental group 2; Figure 9 (c) is a scanning electron microscope image of freeze-dried experimental group 3; Figure 9 (d) is a scanning electron microscope image of freeze-dried experimental group 4; Figure 9 (e) is a scanning electron microscope image of freeze-dried samples from experimental group 5; Figure 10 This is a comparison of the air permeability of silk fabrics in the control group and experimental groups 1-5 of this application. Detailed Implementation

[0028] To make the purpose, technical solutions, and advantages of the experimental group of this application clearer, the technical solutions in the experimental group of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described experimental group is only a part of the experimental group of this application, not all of it. In the following description, specific details such as specific preparations and components are provided only to help fully understand the experimental group of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the experimental group described herein without departing from the scope and spirit of this application. Furthermore, for clarity and brevity, descriptions of known functions and structures are omitted from the experimental group description.

[0029] It should be understood that the phrase "an experimental group" or "this experimental group" throughout the specification means that a specific feature, structure, or characteristic related to the experimental group is included in at least one experimental group of this application. Therefore, "an experimental group" or "this experimental group" appearing throughout the specification does not necessarily refer to the same experimental group. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more experimental groups.

[0030] Furthermore, reference numbers and / or letters may be repeated in different examples in this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various experimental groups and / or settings discussed.

[0031] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0032] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0033] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0034] Example 1 This embodiment describes a method for preparing an anti-UV finishing liquid based on composite nanomaterials.

[0035] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating the preparation method of the UV-resistant finishing liquid based on composite nanomaterials in this application; A method for preparing an anti-UV finishing liquid based on composite nanomaterials includes the following steps: Step S1: Dissolve tannic acid in water according to the ratio to obtain an aqueous solution of tannic acid; Step S2: Add nano-TiO2, cellulose nanofibers, dispersant, and water-based polyurethane binder to the tannic acid aqueous solution according to the proportion to obtain a mixed solution; Step S3: The mixed solution described in S2 is sheared at high speed until a uniform suspension is formed, to obtain a functionally compounded UV-resistant finishing solution.

[0036] Furthermore, the water mentioned in step S1 is deionized water.

[0037] Furthermore, the dispersant mentioned in step S2 is SW-996.

[0038] Furthermore, in step S3, the high-speed shearing speed is 7000-9000 rpm, and the time is 3-8 min.

[0039] Furthermore, in step S3, the high-speed shearing speed is 8000 rpm and the time is 5 min.

[0040] Furthermore, the content of tannic acid in the UV-resistant finishing solution in step S3 is 1wt% to 5wt%.

[0041] Furthermore, in step S3, the content of nano-TiO2 in the UV-resistant finishing liquid is 2wt% to 5wt%, the content of cellulose nanofibers is 2wt% to 7wt%, the content of dispersant is 0.2wt% to 1.5wt%, and the content of waterborne polyurethane adhesive is 1wt% to 6wt%.

[0042] Furthermore, the content of tannic acid in the UV-resistant finishing solution in step S3 is 3wt% to 5wt%.

[0043] Furthermore, in step S3, the content of the nano-TiO2 in the UV-resistant finishing liquid is 3wt%, the content of the cellulose nanofiber is 5wt%, the content of the dispersant is 0.5wt%, and the content of the waterborne polyurethane adhesive is 2wt%.

[0044] Technical results of this experimental group: The initial UPF value of this embodiment is as high as 480.22, and it still maintains 212.25 after 50 washes, demonstrating excellent UV resistance and durability. Breathability decreased by 35%, and the hand feel was considered indistinguishable from untreated fabric by 80% of the respondents, making it suitable for scenarios with extremely high protection requirements.

[0045] Example 2 Based on Example 1, this example is an analysis of the washability of silk fabrics prepared using the UV-resistant finishing solution obtained by the above preparation method.

[0046] (1) Preparation of silk fabrics for control group and experimental group 1) The silk fabric in the control group 0 was untreated.

[0047] 2) The finishing solution used in Experimental Group 1 contains 5 wt% tannic acid, 1 wt% nano-TiO2, 5 wt% cellulose nanofibers, 0.5 wt% dispersant SW-996, and 2 wt% waterborne polyurethane adhesive. The finishing solution used to treat silk fabric includes the following steps: First, the silk fabric is dipped and rubbed twice in the sol, with a rub-to-liquid ratio of 80% and a liquor ratio of 1:20; second, it is dried at 80°C for 2 minutes to remove moisture; finally, the silk fabric is dried at 130°C for 3 minutes to allow the adhesive to crosslink and cure.

[0048] 3) The finishing solution used in Experimental Group 2 contains 2 wt% tannic acid, 3.5 wt% nano-TiO2, 5 wt% cellulose nanofibers, 0.5 wt% dispersant SW-996, and 2 wt% waterborne polyurethane adhesive. The finishing solution used to treat silk fabrics includes the following steps: First, the silk fabrics are dipped and rubbed twice in the sol, with a rub-to-liquid ratio of 80% and a liquor ratio of 1:20. Second, the fabrics are dried at 80°C for 2 minutes to remove moisture. Finally, the silk fabrics are dried at 130°C for 3 minutes to allow the adhesive to crosslink and cure.

[0049] 4) The finishing solution used in Experimental Group 3 contains 3 wt% tannic acid, 3 wt% nano-TiO2, 5 wt% cellulose nanofibers, 0.5 wt% dispersant SW-996, and 2 wt% waterborne polyurethane adhesive. The finishing solution used to treat silk fabric includes the following steps: First, the silk fabric is dipped and rubbed twice in the sol, with a rub-to-liquid ratio of 80% and a liquor ratio of 1:20; second, it is dried at 80°C for 2 minutes to remove moisture; finally, the silk fabric is dried at 130°C for 3 minutes to allow the adhesive to crosslink and cure.

[0050] 5) The finishing solution used in Experimental Group 4 contains 4 wt% tannic acid, 1.5 wt% nano-TiO2, 5 wt% cellulose nanofibers, 0.5 wt% dispersant SW-996, and 2 wt% waterborne polyurethane adhesive. The finishing solution used to treat silk fabric includes the following steps: First, the silk fabric is dipped and rubbed twice in the sol, with a rub-to-liquid ratio of 80% and a liquor ratio of 1:20; second, it is dried at 80°C for 2 minutes to remove moisture; finally, the silk fabric is dried at 130°C for 3 minutes to allow the adhesive to crosslink and cure.

[0051] 6) The finishing solution used in Experimental Group 5 contains 3 wt% tannic acid, 3 wt% nano-TiO2, 5 wt% cellulose nanofibers, 0.5 wt% dispersant SW-996, and 2 wt% waterborne polyurethane adhesive. The finishing solution used to treat silk fabric includes the following steps: First, the silk fabric is dipped and rubbed twice in the sol, with a rub-to-liquid ratio of 80% and a liquor ratio of 1:20; second, it is dried at 80°C for 2 minutes to remove moisture; finally, the silk fabric is dried at 130°C for 3 minutes to allow the adhesive to crosslink and cure.

[0052] (2) Analysis of the finishing and wash resistance of experimental groups 1-5 1) The sorting effect of experimental group 1 Feel: In a blind test conducted by 10 people, 80% believed that there was no significant difference from the untreated fabric.

[0053] Please refer to Figure 2 , Figure 2 (a) SEM image of the silk fabric in Experimental Group 1 of this application before UV-resistant finishing; Figure 2 (a) SEM image of the silk fabric after UV-resistant finishing in Experimental Group 1 of this application. As shown in the figure, the TiO2 nanoparticles and cellulose nanofibers are uniformly distributed on the surface of the silk fabric fibers.

[0054] The UPF value of experimental group 1 was 468.87 after 0 washes and 246.87 after 50 washes, indicating good washability. Breathability decreased by only 15%, and 80% of respondents felt there was no significant difference in hand feel, thus balancing protection and comfort.

[0055] 2) The results of the preparation in experimental group 2 Feel: In a blind test conducted by 10 people, 80% believed that there was no significant difference from the untreated fabric.

[0056] Please refer to Figure 3 , Figure 3 (a) SEM image of the silk fabric in Experimental Group 2 of this application before UV-resistant finishing; Figure 3 (a) SEM image of the silk fabric after UV-resistant finishing in Experimental Group 2 of this application. As shown in the figure, the TiO2 nanoparticles and cellulose nanofibers are uniformly distributed on the surface of the silk fabric fibers.

[0057] Experimental group 2 had a UPF value of 446.48 after 0 washes and 222.03 after 50 washes, demonstrating stable UV resistance. While breathability decreased by 11%, 90% of respondents considered the feel to be identical, indicating the best overall performance. This group is recommended as the preferred formulation.

[0058] 3) The cleaning effect of experimental group 3 Feel: In a blind test conducted by 10 people, 90% believed that there was no significant difference from the untreated fabric.

[0059] Please refer to Figure 4 , Figure 4 (a) SEM image of the silk fabric in experimental group 3 of this application before UV-resistant finishing; Figure 4 (a) SEM image of silk fabric after UV-resistant finishing in Experimental Group 3 of this application. As shown in the figure, TiO2 nanoparticles and cellulose nanofibers are uniformly distributed on the surface of the silk fabric fibers and form a UV-resistant film on the surface of the silk fabric.

[0060] The UPF value of experimental group 3 was 434.17 after 0 washes and 207.51 after 50 washes, demonstrating good durability. Breathability decreased by only 2%, and 90% of respondents felt no difference in hand feel, indicating almost no impact on the fabric's original breathability, making it suitable for applications with extremely high comfort requirements.

[0061] 4) The cleaning effect of experimental group 4 Feel: In a blind test conducted by 10 people, 90% believed that there was no significant difference from the untreated fabric.

[0062] Please refer to Figure 5 , Figure 5 (a) SEM image of the silk fabric in experimental group 4 of this application before UV-resistant finishing; Figure 5 (a) SEM image of the silk fabric after UV-resistant finishing in Experimental Group 4 of this application. As shown in the figure, the TiO2 nanoparticles and cellulose nanofibers are uniformly distributed on the surface of the silk fabric fibers and form a UV-resistant film on the surface of the silk fabric.

[0063] The UPF value of experimental group 4 was 398.85 after 0 washes and 174.39 after 50 washes, indicating reliable UV protection. Breathability remained similar to the original fabric, and 90% of respondents considered the hand feel indistinguishable, thus preserving the natural characteristics of silk to the fullest extent.

[0064] 5) The cleaning effect of experimental group 5 Feel: In a blind test conducted by 10 people, 90% believed that there was no significant difference from the untreated fabric.

[0065] Please refer to Figure 6 , Figure 6 (a) SEM image of the silk fabric in experimental group 5 of this application before UV-resistant finishing; Figure 6 (a) SEM image of silk fabric after UV-resistant treatment in Experimental Group 5 of this application. As shown in the figure, TiO2 nanoparticles and cellulose nanofibers are uniformly distributed on the surface of the silk fabric fibers and form a UV-resistant film on the surface of the silk fabric.

[0066] The UPF value of experimental group 5 was 398.85 after 0 washes and 174.39 after 50 washes, showing stable performance. Breathability remained unchanged, and 90% of respondents considered the feel to be identical, further validating the reliability and versatility of the optimized formula.

[0067] The technical effects of this embodiment are as follows: After 50 washes, the UPF value of the treated silk fabric remains above 50. The rate of UPF value decay during the washing process is significantly reduced, the UV transmittance of the treated silk fabric is significantly reduced, and the UPF value is significantly increased. Even after 50 washes, the UPF value remains above 50 because tannic acid can react with lysine or arginine residues in silk fibroin to form a covalent cross-linked network, thereby enhancing the wash resistance of the self-assembled system on the surface of the silk fabric.

[0068] Example 3 Based on Example 2, this example is an analysis of the UV resistance performance of silk fabrics prepared using the UV-resistant finishing solution obtained by the above preparation method.

[0069] (1) UV protection performance parameters of control group and experimental groups 1-5 The results showed that the UPF, T(UVA), and T(UVB) values ​​of the control group were 20.887, 7.022, and 3.544, respectively. After finishing treatment, the UV resistance of the silk fabric was significantly improved, and the UV transmittance was also greatly reduced. The UV protection factor (UPF) values ​​of the finished silk fabric all exceeded 50, indicating a significant enhancement in UV resistance. Even after washing, the UPF value of the finished silk fabric remained above 50. The T(UVA) and T(UVB) values ​​of the finished silk fabric were both below 5, indicating good blocking effects against UVA and UVB. The UV resistance of the finished silk fabric is mainly attributed to the synergistic effect of cellulose nanofibers (CNF), tannic acid, and titanium dioxide (TiO2) in the finishing solution. The synergistic mechanism of the three UV inhibitors mainly includes: the phenolic hydroxyl groups of tannic acid form hydrogen bonds with the hydroxyl groups of cellulose nanofibers, which can enhance the absorption of ultraviolet light in the approximately 290 nm wavelength band; the cellulose nanofibers in the finishing solution enhance ultraviolet scattering through their micron-scale structure; and TiO2 enhances ultraviolet scattering through its dihedral crystal structure.

[0070] (2) UV protection efficacy of control group and experimental groups 1-5 To visually assess the UV protection efficacy of silk fabrics, a UV sensor card was used for measurement, and the results are as follows: Figure 7 As shown, Figure 7 The figures show the UV-induced test results of silk fabrics in the control group and experimental groups 1-5 of this application. Figure 7 (a) is a graph showing the UV-induced test results for the control group. Figure 7 (b) is a graph showing the ultraviolet-induced test results for experimental group 1. Figure 7 (c) is a graph showing the ultraviolet-induced test results of experimental group 2. Figure 7 (d) shows the UV-induced test results for experimental group 3. Figure 7(e) is a graph showing the ultraviolet-induced test results for experimental group 4. Figure 7 (f) shows the results of the ultraviolet-induced test for experimental group 5.

[0071] Figure 7 The depth of color is inversely proportional to the fabric's UV protection capability: the darker the hue, the worse the UV protection and the higher the UV intensity. Results showed that the control group (untreated fabric) exhibited the darkest color under direct UV irradiation, with UV energy levels exceeding 500-1000 μW / cm². In contrast, experimental groups 1 and 5 showed lighter colors, corresponding to UV energy levels between 150 and 500 μW / cm². Furthermore, experimental groups 2 to 4 exhibited the lightest colors, with UV energy levels below 100 μW / cm². Under these conditions, only a very small amount of UV radiation penetrated the fabric, posing a relatively low potential health hazard and thus meeting daily UV protection standards.

[0072] The technical results of this experimental group: A higher UPF value indicates better protection against ultraviolet radiation for silk fabrics. Even after washing, the UPF value of the finished fabric remained above 50, indicating a significant enhancement in its UV resistance.

[0073] Example 4 Based on Example 2, this example is an analysis of the freeze-dried form of the UV-resistant finishing solution prepared by the above preparation method.

[0074] Please refer to Figure 8 , Figure 8 Scanning electron microscope images of tannic acid, cellulose nanofibers, and nano-TiO2. Figure 8 (a) is a scanning electron microscope image of tannic acid. Figure 8 (b) is a scanning electron microscope image of cellulose nanofibers. Figure 8 (c) shows an SEM image of titanium dioxide (TiO2).

[0075] The results show: Figure 8 (a) shows a scanning electron microscope image of tannic acid, which exhibits a layered structure. Figure 8 (b) shows a scanning electron microscope image of cellulose nanofibers, revealing a compact three-dimensional network structure. This complex interwoven structure can reflect or scatter ultraviolet (UV) light, thereby reducing its penetrability. Figure 8 (c) shows a SEM image of titanium dioxide (TiO2), characterized by its granular morphology. Titanium dioxide can enhance the scattering efficiency of ultraviolet light through the Mie scattering mechanism.

[0076] Please refer to Figure 9 , Figure 9Scanning electron microscope images of freeze-dried solutions with different UV-resistant finishing agents; Figure 9 (a) is a scanning electron microscope image of freeze-dried experimental group 1; Figure 9 (b) is a scanning electron microscope image of freeze-dried samples from experimental group 2; Figure 9 (c) is a scanning electron microscope image of freeze-dried experimental group 3; Figure 9 (d) is a scanning electron microscope image of freeze-dried experimental group 4; Figure 9 (e) is a scanning electron microscope image of freeze-dried experimental group 5.

[0077] As shown in the figure, after freeze-drying, the UV-resistant finishing solution exhibits a porous microstructure. This porous three-dimensional network structure enhances UV scattering and reflection, thus improving the UV blocking effect. As the mass fraction of titanium dioxide decreases, the density of its porous microstructure gradually weakens, with the UV-resistant finishing solution in experimental group 5 exhibiting the largest porosity.

[0078] The technical effect of this embodiment is that after freeze-drying, the UV-resistant finishing liquid exhibits a porous microstructure. The porous three-dimensional network structure of the UV-resistant finishing liquid can enhance the scattering and reflection of ultraviolet rays, which is more conducive to improving the UV blocking effect.

[0079] Example 5 Based on Example 2, this example is a verification of the air permeability of silk fabrics in the control group and experimental groups 1-5 of this application.

[0080] Tannins in UV-protective finishing solutions can interact with silk proteins through non-covalent bonds, forming a thin film on the fiber surface. Simultaneously, tannin molecules may partially block the micropores between fibers, reducing porosity and thus decreasing air permeability. In contrast, titanium dioxide (TiO2) nanoparticles, when attached to the fiber surface, can maintain pore integrity. However, when TiO2 is excited by ultraviolet light, it may oxidize the silk surface, fine-tuning fiber roughness and indirectly reducing air permeability.

[0081] Please refer to Figure 10 , Figure 10 This is a comparison chart of the air permeability of silk fabrics in the control group and experimental groups 1-5 of this application. The results show that the air permeability of the treated silk fabrics in experimental groups 1-5 is lower than that of the untreated fabrics. The air permeability of experimental group 1 decreased by 35% compared to the control group; the air permeability of experimental group 2 decreased by 15% compared to the control group; the air permeability of experimental group 3 decreased by 11% compared to the control group; the air permeability of experimental group 4 decreased by 11% compared to the control group; and the air permeability of experimental group 5 remained essentially unchanged compared to the control group.

[0082] The technical effect of this embodiment is that the air permeability of silk fabrics is significantly affected by the concentrations of TiO2 and tannic acid in the finishing solution. As the TiO2 content in the UV-protective finishing solution decreases and the tannic acid content increases, the fabric's air permeability continuously improves. The fabric exhibits optimal air permeability when the tannic acid content reaches 5% and the TiO2 content is 1%.

[0083] The specific embodiments described above are not intended to limit the present invention, and the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these experimental groups that fall within the spirit and principles of the present invention should be included within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing an anti-UV finishing liquid based on composite nanomaterials, characterized in that, Includes the following steps: Step S1: Dissolve tannic acid in water according to the ratio to obtain an aqueous solution of tannic acid; Step S2: Add nano-TiO2, cellulose nanofibers, dispersant, and water-based polyurethane binder to the tannic acid aqueous solution according to the proportion to obtain a mixed solution; Step S3: The mixed solution described in S2 is sheared at high speed until a uniform suspension is formed, to obtain a functionally compounded UV-resistant finishing solution.

2. The method for preparing an anti-UV finishing liquid based on composite nanomaterials according to claim 1, characterized in that, In step S3, the high-speed shearing speed is 7000-9000 rpm, and the time is 3-8 min.

3. The method for preparing an anti-UV finishing liquid based on composite nanomaterials according to claim 1, characterized in that, The content of tannic acid in the UV-resistant finishing solution in step S3 is 1wt% to 5wt%.

4. The method for preparing an anti-UV finishing liquid based on composite nanomaterials according to claim 1, characterized in that, In step S3, the content of nano-TiO2 in the UV-resistant finishing liquid is 2wt% to 5wt%, the content of cellulose nanofibers is 2wt% to 7wt%, the content of dispersant is 0.2wt% to 1.5wt%, and the content of waterborne polyurethane adhesive is 1wt% to 6wt%.

5. The method for preparing an anti-UV finishing liquid based on composite nanomaterials according to claim 2, characterized in that, The content of tannic acid in the UV-resistant finishing solution in step S3 is 3wt% to 5wt%.

6. The method for preparing an anti-UV finishing liquid based on composite nanomaterials according to claim 3, characterized in that, In step S3, the content of nano-TiO2 in the UV-resistant finishing liquid is 3wt%, the content of cellulose nanofiber is 5wt%, the content of dispersant is 0.5wt%, and the content of waterborne polyurethane adhesive is 2wt%.

7. A method for preparing an anti-UV finishing liquid based on composite nanomaterials according to claim 5 or 6, characterized in that, In step S3, the high-speed shearing speed is 8000 rpm and the time is 5 min.

8. The application of the UV-resistant finishing solution obtained by the preparation method according to any one of claims 1-7 in the preparation of washable UV-resistant silk fabrics.

9. A method for preparing a washable, UV-resistant silk fabric using an anti-UV finishing solution obtained according to any one of claims 1-7, characterized in that... Includes the following steps: Step 1: Padding: The silk fabric is dipped and paved twice in the sol; Step 2: Pre-drying: Dry the silk fabric obtained in Step 1 at a temperature of 70℃~80℃ for 2~3 minutes; Step 3: Baking: Bake the silk fabric obtained in Step 2 at a temperature of 120℃~130℃ for 2~3 minutes to allow the adhesive to crosslink and cure.

10. The method for preparing washable UV-resistant silk fabrics using the UV-resistant finishing solution obtained according to claim 9, characterized in that... In step 1, the liquid yield is 80% and the liquor ratio is 1:20.

Images