Uvioresistant dyes with tannic acid as coupling component, process for their preparation and use

Abstract

The application belongs to the technical field of organic dyes, and particularly relates to an ultraviolet-resistant dye taking tannic acid as a coupling component, and a preparation method and application thereof. Under stirring, a diazonium salt solution of an arylamine derivative is added into a mixed solution to react, and after the addition is completed, the stirring reaction is continued to obtain a reaction liquid; the reaction liquid is adjusted in pH, evaporated, filtered, and dried to obtain the ultraviolet-resistant dye taking tannic acid as the coupling component. The ultraviolet-resistant dye taking tannic acid as the coupling component in the application can impart color and ultraviolet resistance to real silk simultaneously during dyeing; the dyeing process is simple and short in time, has small damage to real silk, has simple dyeing liquid composition, and is easy to handle in subsequent wastewater treatment, and the whole dyeing process is low-carbon and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of organic dye technology, specifically relating to an anti-ultraviolet dye with tannic acid as a coupling component, its preparation method, and its application. Background Technology

[0002] Silk, with its soft luster and excellent comfort, is hailed as the "Queen of Fibers" and is a high-end textile material. Currently, silk dyeing primarily uses chemically synthesized dyes, mainly acid dyes and reactive dyes. Acid dyes require acidic conditions and high dyeing temperatures, easily causing "gray damage" to the silk and ruining its luster, and also resulting in poor wet fastness. Reactive dyes solve the problem of poor wet fastness in silk fabrics, but they present a series of problems such as dye hydrolysis, poor leveling, difficulty in color modification, and high salt content in wastewater. Furthermore, chemically synthesized dyes only impart color to silk and cannot give it functional properties such as UV protection.

[0003] With increasing public concern about environmental and health issues, the environmental hazards and raw material bottlenecks of chemically synthesized dyes have become increasingly prominent. Therefore, the development of natural and environmentally friendly dyes has become a hot topic in the industry, with plant dyes receiving particular attention. Plant dyes can not only dye silk but also endow silk with certain antibacterial and anti-ultraviolet functions. Commonly used plant dyes include sappanwood (Jiang Jian, Zhang Hui, Deng Yongqin, et al. Anti-ultraviolet modification of sappanwood pigment and its functional dyeing of silk fabrics [J]. Silk, 2025, 62(11):54-61.), tea polyphenols (Fang Jiaojiao, Zhao Peihong, Zhao Yitao, et al. Preparation of catechins from tea stalks and their dyeing and functional modification of silk fabrics [J]. Modern Textile Technology, 2024, 32(06):1-8.), and cassia seed (Wang Tian. Study on high fastness dyeing and functionality of cassia seed extract on silk fabrics [J]. Silk, 2020, 57(10):6-11.), etc. However, plant dyes suffer from drawbacks such as difficulty in large-scale production, poor color fastness, high cost, and difficulty in reproducing dyeing results, thus hindering their industrial application. Therefore, it is of great significance to combine the advantages of chemically synthesized dyes and plant dyes to develop a novel dye that combines dyeing and UV protection functions.

[0004] Chinese patent CN102321383A discloses a method for preparing plant tannin dye solution and its application in dyeing silk fabrics. It uses larch bark, bayberry bark, black thorn bark, acorn, or gallnut as raw materials, and extracts the dye solution with acetone or water as the extractant; or it uses tannin products from larch, bayberry, black thorn, acorn, or gallnut as raw materials, and extracts the dye solution with water as the extractant. The plant tannin dye solution prepared by this patent, or the dye prepared from the dye solution, is applied to dyeing silk fabrics, resulting in significant dyeing effects. It effectively solves the technical problem of low color fastness of existing plant dyes and can be combined with mordant dyeing technology to obtain richer dyeing effects. However, the method for preparing the dye solution in this patent is complex, energy-intensive, and costly. The dyeing quality is unstable due to multiple factors such as the origin and maturity of the raw materials, making it unsuitable for industrial application. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-ultraviolet dye with tannic acid as the coupling component. This dye is prepared from tannic acid, which is derived from plants and is biodegradable, through diazotization and coupling reactions. The preparation method is simple and the production cost is low. This invention also provides a preparation method and application of the anti-ultraviolet dye with tannic acid as the coupling component.

[0006] The structural formula of the UV-resistant dye with tannic acid as the coupling component described in this invention is as follows:

[0007] ,

[0008] The structural formulas for R1, R2, R3, R4, and R5 are as follows:

[0009] ,

[0010] Among them, the structural formulas of R6, R7 and R8 are all -H, or One of them; among them, R9 and R 10 Independently selected from one of -H, -COONa (sodium carboxylate), -SO3Na (sodium sulfonate), -NO2, -COOH, -SO3H, -OH, -SH, or -CN; R 11 R 12 and R 13 Independently selected from one of -H, -COONa (sodium carboxylate), -SO3Na (sodium sulfonate), -OH, -SO3H or -COOH, and R 11 R 12 and R 13 Cannot both be -H;

[0011] When R1, R2, R3, R4 and R5 are the same, R6, R7 and R8 cannot all be -H.

[0012] The method for preparing the UV-resistant dye with tannic acid as the coupling component according to the present invention includes the following steps:

[0013] (1) Under stirring conditions, the diazonium salt solution of the aromatic amine derivative is added to the mixture for reaction. After the addition is complete, the reaction is stirred to obtain the reaction solution.

[0014] (2) The pH of the reaction solution was adjusted, evaporated, filtered, and dried to obtain an anti-UV dye with tannic acid as the coupling component.

[0015] The preparation method of the diazonium salt solution of the aromatic amine derivative in step (1) is either Method 1 or Method 2:

[0016] Method 1: Add aromatic amine derivative and acid solution to water in sequence, react to obtain acidic salt solution of aromatic amine derivative, cool the acidic salt solution of aromatic amine derivative and add sodium nitrite aqueous solution, stir to react and obtain diazonium salt solution of aromatic amine derivative.

[0017] Method 2: Add the aromatic amine derivative and alkaline solution to water in sequence, react to obtain an alkaline salt solution of the aromatic amine derivative, add sodium nitrite to the alkaline salt solution of the aromatic amine derivative to obtain a mixed solution; under stirring conditions, add the mixed solution to an acid solution to react, and continue stirring after the addition is complete to obtain a diazonium salt solution of the aromatic amine derivative.

[0018] In Method 1, the aromatic amine derivative includes one of the following: aniline, p-nitroaniline, m-nitroaniline, 2,4-dinitroaniline, p-aminophenol, m-aminophenol, 2-amino-1,4-dihydroxybenzene, 2-amino-1,3-benzenediol, 4-aminobenzenethiophenol, 3-aminobenzenethiophenol, p-cyanoaniline, m-cyanoaniline, 1-amino-2-naphthol, or 8-amino-2-naphthol; the ratio of water to the aromatic amine derivative is 2-100:1, where water is expressed in mL and the aromatic amine derivative in mmol; the reaction... The reaction is carried out at room temperature until the aromatic amine derivative is completely dissolved. The cooling temperature is 0-10℃, the concentration of the sodium nitrite aqueous solution is 10-50 wt.%, the molar ratio of the aromatic amine derivative to sodium nitrite in the sodium nitrite aqueous solution is 1:1-1.1, the stirring time is 0.5-5 h, the stirring temperature is 0-10℃, the acid solution is hydrochloric acid solution or sulfuric acid solution, the hydrogen ion concentration in the acid solution is 0.2-20 mol / L, and the molar ratio of the aromatic amine derivative to hydrogen ions in the acid solution is 1:2-10.

[0019] In Method 2, the aromatic amine derivatives include one of the following: p-aminobenzoic acid, m-aminobenzoic acid, 4-aminophthalic acid, p-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, 2,4-disulfonic acid aniline, 4-amino-1-naphthalenesulfonic acid, 5-amino-1-naphthalenesulfonic acid, 8-amino-2-naphthalenesulfonic acid, 2-amino-5,7-naphthalenedisulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 1-amino-8-naphthol-3,6-disulfonic acid, 2-amino-5-naphthol-7-sulfonic acid, or 2-amino-8-naphthol-6-sulfonic acid.

[0020] In Method 2, the ratio of water to aromatic amine derivative is 2-100:1, where water is expressed in mL and aromatic amine derivative in mmol. The reaction is carried out at room temperature until the aromatic amine derivative is completely dissolved. The pH of the aromatic amine derivative solution is 7-8, and the molar ratio of aromatic amine derivative to sodium nitrite is 1:1-1.1. The reaction temperature is 0-10℃ when the mixed solution is added to the acid solution, and the stirring time is 0.5-5h. The alkaline solution is one or more of sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, or sodium hydroxide aqueous solution, with a concentration of 1-40 wt.%. The molar ratio of protons in the aromatic amine derivative to the acid solution is 1:2-10, and the hydrogen ion concentration in the acid solution is 0.2-20 mol / L.

[0021] In step (1), the reaction temperature is controlled at 0-10℃ and an alkaline solution is added to adjust the pH to 6-9. The alkaline solution is one of sodium carbonate aqueous solution, sodium bicarbonate aqueous solution or sodium hydroxide aqueous solution, and the concentration of the alkaline solution is 1-40 wt.%. The temperature of the stirring reaction is 0-10℃ and the stirring reaction time is 0.5-2h.

[0022] The preparation method of the mixture in step (1) is as follows: under anaerobic conditions, tannic acid and water are mixed evenly and then an alkaline solution is added to obtain the mixture. The ratio of tannic acid to water is 1-40:1, where tannic acid is expressed in mmol and water in L. The molar ratio of tannic acid to the diazonium salt of the aromatic amine derivative in the diazonium salt solution is 1:1-10. The pH of the mixture is 6-9. The alkaline solution is one or more of sodium bicarbonate aqueous solution, sodium carbonate aqueous solution or sodium hydroxide aqueous solution. The concentration of the alkaline solution is 1-40 wt.%, preferably 5-15 wt.%.

[0023] In step (2), the pH is adjusted by adding an acid solution to adjust the pH to 2-6. The acid solution is hydrochloric acid solution or sulfuric acid solution, preferably hydrochloric acid solution, and the hydrogen ion concentration in the acid solution is 0.2-20 mol / L. Evaporation is carried out by vacuum distillation or rotary evaporation, preferably rotary evaporation, and the evaporation temperature is 50-80℃, preferably 50-60℃. Drying is carried out by vacuum drying or oxygen-free drying under inert gas protection, preferably vacuum drying, and the drying temperature is 50-80℃, preferably 50-60℃.

[0024] The application of the UV-resistant dye with tannic acid as a coupling component described in this invention is in the dyeing of silk textiles.

[0025] The application of the UV-resistant dye with tannic acid as the coupling component described in this invention involves preparing a dyeing solution with the UV-resistant dye with tannic acid as the coupling component, adjusting the pH of the dyeing solution to 3-7 with acetic acid, immersing the silk textile in the dyeing solution at a constant temperature for dyeing, removing it, washing it with water, and drying it to obtain the dyed silk textile.

[0026] The UV-resistant dye with tannic acid as the coupling component described in this invention uses tannic acid and non-carcinogenic aromatic amine derivatives as raw materials. First, a diazonium salt is generated through the diazotization reaction of the aromatic amine derivative of the diazonium component. Then, the UV-resistant dye is prepared by the coupling reaction between the diazonium salt and the coupling component tannic acid.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) The coupling component of this invention is tannic acid, which has the advantages of safety, environmental protection and biodegradability; the diazo component is an aromatic amine derivative, which has the advantages of low price, wide availability and excellent safety.

[0029] (2) The diazotization reaction and coupling reaction in this invention are both classic unit reactions, with mild reaction conditions, short reaction time and no need for special reaction equipment. Therefore, the preparation method of this invention is simple, requires no additional equipment investment, and has low production cost.

[0030] (3) The UV-resistant dye with tannic acid as the coupling component in this invention is biodegradable and can simultaneously impart color and UV-resistant function to silk during dyeing. The dyeing process is simple and time-consuming, causes little damage to silk, has good dyeing reproducibility, and has good application prospects. The dyeing solution has a simple composition, the subsequent wastewater is easy to treat, and the whole dyeing process is low-carbon and environmentally friendly.

[0031] (4) The color of the UV-resistant dye with tannic acid as the coupling component in this invention can vary depending on the structure of the selected aromatic amine derivative, and can present a rich variety of colors. The UV-resistant dye with tannic acid as the coupling component contains one or more azo groups. The azo group is a chromophore. Different colors and shades of dye can be prepared and dyed products can be obtained by controlling the number of azo groups, thus solving the problem of single color when dyeing with tannic acid alone. In this invention, the tannic acid structure of the UV-resistant dye with tannic acid as the coupling component contains a large number of polar phenolic hydroxyl groups and ester bonds, which can form a large number of hydrogen bonds with the amino or hydroxyl groups of silk, thereby increasing the binding force between the dye and silk, improving the wash fastness and dyeing stability, and reducing the risk of color fading. In addition, the phenolic hydroxyl group, as a highly efficient UV absorber, can absorb ultraviolet light (mainly the UVB band) through electronic transitions. The conjugated system composed of aromatic ring and azo group disperses ultraviolet energy through the conjugated structure (covering the UVA band). The two work together to comprehensively block ultraviolet light of different bands, enhance the UV resistance of the dye, and reduce the damage of ultraviolet light to dyed textiles. The strong polarity of the polyhydroxyl structure can improve the dispersibility of the dye in aqueous solution, making the dye adsorption more uniform during the dyeing process and avoiding the problem of uneven dyeing. The numerous phenolic hydroxyl groups of tannic acid can act as hydrogen bond donors to form intramolecular hydrogen bonds with nitrogen atoms on azo groups, thereby making the spatial conformation of dye molecules more stable and reducing the risk of photodegradation of chromophores. The conjugated system formed by the aromatic ring and azo group can undergo π-π stacking with the benzene ring containing the phenolic hydroxyl group, further expanding the conjugated range of the entire molecule and enhancing the color development ability and ultraviolet absorption efficiency of the dye. Attached Figure Description

[0032] Figure 1 The UV-Vis absorption spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 1 is shown.

[0033] Figure 2 The image shows the 1H NMR spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 1.

[0034] Figure 3 The image shows the 1H NMR spectrum of tannic acid in Example 1.

[0035] Figure 4 The image shows the UV-Vis absorption spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 2.

[0036] Figure 5 The image shows the UV-Vis absorption spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 3.

[0037] Figure 6 The UV-Vis absorption spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 4 is shown.

[0038] Figure 7 The UV-Vis absorption spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 5 is shown.

[0039] Figure 8 The UV-Vis absorption spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 6 is shown.

[0040] Figure 9 The UV-Vis absorption spectrum of the UV-resistant dye with tannic acid as the coupling component in Example 7 is shown. Detailed Implementation

[0041] The present invention will be further described below with reference to embodiments.

[0042] Example 1

[0043] S1. Preparation of diazonium salt solution of aniline:

[0044] 10 mmol of aniline was added to 20 mL of water, followed by 30 mL of 1 mol / L hydrochloric acid solution (containing 30 mmol of HCl). The mixture was reacted at room temperature until the aniline was completely dissolved to obtain an aniline hydrochloride solution. After the aniline hydrochloride solution was cooled to 0 °C, 7.59 g of 10 wt.% sodium nitrite aqueous solution (containing 11 mmol of sodium nitrite) was added dropwise to the aniline hydrochloride solution. The mixture was stirred at 0 °C for 1 h to obtain a diazonium salt solution of aniline.

[0045] S2. Preparation of UV-resistant dyes with tannic acid as the coupling component:

[0046] (1) Under anaerobic conditions, 2 mmol of tannic acid was mixed with 100 mL of water, and then a 10 wt.% sodium carbonate aqueous solution was added dropwise to obtain a mixture with pH 8. Under stirring conditions, the diazonium salt solution of aniline obtained in S1 was added dropwise to the above mixture for reaction. The reaction temperature was controlled at 5 °C, and a 10 wt.% sodium carbonate aqueous solution was added to adjust the pH to 8. After the addition was completed, the reaction was stirred at 0 °C for 0.5 h to obtain the reaction solution.

[0047] (2) Add 2 mol / L hydrochloric acid solution to the reaction solution in step (1) to adjust the pH to 4, remove half of the water by rotary evaporation at 60°C, filter, and vacuum dry at 60°C to obtain the UV-resistant dye with tannic acid as the coupling component; the structural formula of the UV-resistant dye with tannic acid as the coupling component is as follows:

[0048] ;

[0049] Testing revealed that the nitrogen content in the UV-resistant dye with tannic acid as the coupling component was 6.11 wt.% (theoretical value 6.30 wt.%), and the dye exhibited a distinct color, indicating the presence of azo groups. The UV-Vis absorption spectrum of this dye is shown below. Figure 1 The 1H NMR spectrum of this dye is shown below. Figure 2 , 1 ¹H NMR (400 MHz, DMSO-d6, δ ppm): 9.38 (s, 25H), 7.44 (m, 40H); ¹H NMR spectrum of tannic acid is shown below. Figure 3 , 1 ¹H NMR (400 MHz, DMSO-d6, δ ppm): 9.41 (s, 25H), 7.26-6.64 (m, 20H); Comparing the ¹H NMR spectra of the raw material tannic acid and the UV-resistant dye with tannic acid as the coupling component, it can be found that the ratio of the number of phenolic hydroxyl H [9.41 (s, 25H)] to the number of H [7.26-6.64 (m, 20H)] on the aromatic ring in the ¹H NMR spectrum of tannic acid is 25:20. Similarly, in the ¹H NMR spectrum of the UV-resistant dye with tannic acid as the coupling component, the ratio of the number of phenolic hydroxyl H [9.38 (s, 25H)] to the number of H [7.44 (m, 20H)] on the aromatic ring is 25:20. The ratio of the number of H groups (40H) is 25:40, indicating a change in the proportion of the two H groups. This suggests that a new aromatic ring structure has been introduced into the tannic acid molecule, which indirectly confirms the successful preparation of the UV-resistant dye structure with tannic acid as the coupling component.

[0050] Applications of UV-resistant dyes with tannic acid as the coupling component:

[0051] A UV-resistant dye with tannic acid as the coupling component was mixed with water to prepare a dyeing solution with a concentration of 1 g / L. The pH of the dyeing solution was adjusted to 4 with acetic acid. The silk fabric was immersed in the dyeing solution at a constant temperature of 60°C for 30 minutes at a liquor ratio of 1:30. The fabric was then removed, washed with water, and dried to obtain the dyed silk fabric.

[0052] Example 2

[0053] S1. Preparation of diazonium salt solution of p-aminobenzenesulfonic acid:

[0054] Add 10 mmol of p-aminobenzenesulfonic acid to 30 mL of water, then add 10 wt.% sodium carbonate aqueous solution dropwise. React at room temperature until p-aminobenzenesulfonic acid is completely dissolved to obtain a sodium p-aminobenzenesulfonate solution with pH 8. Add 11 mmol of sodium nitrite to the sodium p-aminobenzenesulfonate solution to obtain a mixed solution. Under stirring, add the above mixed solution dropwise to 20 mL of 2 mol / L hydrochloric acid solution (containing 40 mmol HCl) and react at 5 °C. After the addition is complete, continue stirring at 5 °C for 2 h to obtain a diazonium salt solution of p-aminobenzenesulfonic acid.

[0055] S2. Preparation of UV-resistant dyes with tannic acid as the coupling component:

[0056] (1) Under anaerobic conditions, 2 mmol of tannic acid was mixed with 100 mL of water, and then a 10 wt.% sodium carbonate aqueous solution was added dropwise to obtain a mixture with a pH of 9. Under stirring conditions, the diazonium salt solution of p-aminobenzenesulfonic acid obtained in S1 was added dropwise to the above mixture for reaction. The reaction temperature was controlled at 0℃, and a 10 wt.% sodium carbonate aqueous solution was added to adjust the pH to 9. After the addition was completed, the reaction was stirred at 0℃ for 0.5 h to obtain the reaction solution.

[0057] (2) Add 1 mol / L hydrochloric acid solution to the reaction solution in step (1) to adjust the pH to 5, remove half of the water by rotary evaporation at 60°C, filter, and vacuum dry at 60°C to obtain the UV-resistant dye with tannic acid as the coupling component; the structural formula of the UV-resistant dye with tannic acid as the coupling component is as follows:

[0058] ;

[0059] Testing revealed that the nitrogen content in the UV-resistant dye with tannic acid as the coupling component was 5.02 wt.% (theoretical value 5.13 wt.%), and the dye exhibited a distinct color, indicating the presence of azo groups. The UV-Vis absorption spectrum of this dye is shown below. Figure 4 .

[0060] Applications of UV-resistant dyes with tannic acid as the coupling component:

[0061] A UV-resistant dye with tannic acid as the coupling component was mixed with water to prepare a dyeing solution with a concentration of 1 g / L. The pH of the dyeing solution was adjusted to 4 with acetic acid. The silk fabric was immersed in the dyeing solution at a constant temperature of 60°C for 30 minutes at a liquor ratio of 1:30. The fabric was then removed, washed with water, and dried to obtain the dyed silk fabric.

[0062] Example 3

[0063] S1. Preparation of diazonium salt solution of p-aminobenzoic acid:

[0064] 10 mmol of p-aminobenzoic acid was added to 20 mL of water, followed by the addition of a 40 wt.% sodium hydroxide aqueous solution. The reaction was carried out at room temperature until the p-aminobenzoic acid was completely dissolved, yielding a sodium p-aminobenzoate solution with a pH of 7. 10.5 mmol of sodium nitrite was added to the sodium p-aminobenzoate solution to obtain a mixed solution. Under stirring, the above mixed solution was added dropwise to 100 mL of a 0.2 mol / L hydrochloric acid solution (containing 20 mmol of HCl) and the reaction was carried out at 0 °C. After the addition was completed, the reaction was continued to be stirred at 0 °C for 5 h to obtain a diazonium salt solution of p-aminobenzoic acid.

[0065] S2. Preparation of UV-resistant dyes with tannic acid as the coupling component:

[0066] (1) Under anaerobic conditions, 2 mmol of tannic acid was mixed with 100 mL of water, and then 10 wt.% sodium hydroxide aqueous solution was added dropwise to obtain a mixture with pH 9. Under stirring conditions, the diazonium salt solution of p-aminobenzoic acid obtained in S1 was added dropwise to the above mixture for reaction. The reaction temperature was controlled at 0℃, and 10 wt.% sodium carbonate aqueous solution was added to adjust the pH to 9. After the addition was completed, the reaction was stirred at 5℃ for 0.5 h to obtain the reaction solution.

[0067] (2) Add 1 mol / L hydrochloric acid solution to the reaction solution in step (1) to adjust the pH to 5, remove half of the water by rotary evaporation at 60°C, filter, and vacuum dry at 60°C to obtain the UV-resistant dye with tannic acid as the coupling component; the structural formula of the UV-resistant dye with tannic acid as the coupling component is as follows:

[0068] ;

[0069] Testing revealed that the nitrogen content in the UV-resistant dye with tannic acid as the coupling component was 5.29 wt.% (theoretical value 5.49 wt.%), and the dye exhibited a distinct color, indicating the presence of azo groups. The UV-Vis absorption spectrum of this dye is shown below. Figure 5 .

[0070] Applications of UV-resistant dyes with tannic acid as the coupling component:

[0071] A UV-resistant dye with tannic acid as the coupling component was mixed with water to prepare a dyeing solution with a concentration of 1 g / L. The pH of the dyeing solution was adjusted to 4 with acetic acid. The silk fabric was immersed in the dyeing solution at a constant temperature of 60°C for 30 minutes at a liquor ratio of 1:30. The fabric was then removed, washed with water, and dried to obtain the dyed silk fabric.

[0072] Example 4

[0073] Preparation of diazonium salt solution of S1,4-aminophthalic acid:

[0074] 10 mmol of 4-aminophthalic acid was added to 100 mL of water, followed by the addition of a 1 wt.% sodium bicarbonate aqueous solution. The reaction was carried out at room temperature until the 4-aminophthalic acid was completely dissolved, yielding a sodium salt solution with a pH of 7.5. 11 mmol of sodium nitrite was added to the sodium salt solution to obtain a mixed solution. Under stirring, the above mixed solution was added dropwise to 5 mL of a 20 mol / L hydrochloric acid solution (containing 100 mmol HCl) and the reaction was carried out at a temperature of 10 °C. After the addition was completed, the reaction was continued to be stirred at 10 °C for 0.5 h to obtain a diazonium salt solution of 4-aminophthalic acid.

[0075] S2. Preparation of UV-resistant dyes with tannic acid as the coupling component:

[0076] (1) Under anaerobic conditions, 2 mmol of tannic acid was mixed with 200 mL of water, and then a 10 wt.% sodium carbonate aqueous solution was added dropwise to obtain a mixture with a pH of 9. Under stirring conditions, the diazonium salt solution of 4-aminophthalic acid obtained in S1 was added dropwise to the above mixture for reaction. The reaction temperature was controlled at 0 °C, and a 10 wt.% sodium carbonate aqueous solution was added to adjust the pH to 8. After the addition was completed, the reaction was stirred at 5 °C for 0.5 h to obtain the reaction solution.

[0077] (2) Add 0.5 mol / L sulfuric acid solution to the reaction solution in step (1) to adjust the pH to 4, remove half of the water by rotary evaporation at 60°C, filter, and vacuum dry at 60°C to obtain the UV-resistant dye with tannic acid as the coupling component; the structural formula of the UV-resistant dye with tannic acid as the coupling component is as follows:

[0078] ;

[0079] Testing revealed that the nitrogen content in the UV-resistant dye with tannic acid as the coupling component was 4.67 wt.% (theoretical value 4.86 wt.%), and the dye exhibited a distinct color, indicating the presence of azo groups. The UV-Vis absorption spectrum of this dye is shown below. Figure 6 .

[0080] Applications of UV-resistant dyes with tannic acid as the coupling component:

[0081] A UV-resistant dye with tannic acid as the coupling component was mixed with water to prepare a dyeing solution with a concentration of 1 g / L. The pH of the dyeing solution was adjusted to 4 with acetic acid. The silk fabric was immersed in the dyeing solution at a constant temperature of 60°C for 30 minutes at a liquor ratio of 1:30. The fabric was then removed, washed with water, and dried to obtain the dyed silk fabric.

[0082] Example 5

[0083] Preparation of diazonium salt solution of S1,5-amino-1-naphthalenesulfonic acid:

[0084] 10 mmol of 5-amino-1-naphthalenesulfonic acid was added to 50 mL of water, followed by the addition of a 2 wt.% sodium bicarbonate aqueous solution. The reaction was carried out at room temperature until the 5-amino-1-naphthalenesulfonic acid was completely dissolved, yielding a sodium salt solution with a pH of 7.5. 11 mmol of sodium nitrite was added to the sodium salt solution to obtain a mixed solution. Under stirring, the above mixed solution was added dropwise to 5 mL of a 10 mol / L hydrochloric acid solution (containing 50 mmol HCl) and the reaction was carried out at a temperature of 10 °C. After the addition was completed, the reaction was continued to be stirred at 10 °C for 0.5 h to obtain a diazonium salt solution of 5-amino-1-naphthalenesulfonic acid.

[0085] S2. Preparation of UV-resistant dyes with tannic acid as the coupling component:

[0086] (1) Under anaerobic conditions, 2 mmol of tannic acid was mixed with 200 mL of water, and then a 10 wt.% sodium carbonate aqueous solution was added dropwise to obtain a mixture with a pH of 9. Under stirring conditions, the diazonium salt solution of 5-amino-1-naphthalenesulfonic acid obtained in S1 was added dropwise to the above mixture for reaction. The reaction temperature was controlled at 2 °C, and a 10 wt.% sodium carbonate aqueous solution was added to adjust the pH to 8. After the addition was completed, the reaction was stirred at 5 °C for 0.5 h to obtain the reaction solution.

[0087] (2) Add 0.5 mol / L sulfuric acid solution to the reaction solution in step (1) to adjust the pH to 5, remove half of the water by rotary evaporation at 60°C, filter, and vacuum dry at 60°C to obtain the UV-resistant dye with tannic acid as the coupling component; the structural formula of the UV-resistant dye with tannic acid as the coupling component is as follows:

[0088] ;

[0089] Testing revealed that the nitrogen content in the UV-resistant dye with tannic acid as the coupling component was 4.61 wt.% (theoretical value 4.70 wt.%), and the dye exhibited a distinct color, indicating the presence of azo groups. The UV-Vis absorption spectrum of this dye is shown below. Figure 7 .

[0090] Applications of UV-resistant dyes with tannic acid as the coupling component:

[0091] A UV-resistant dye with tannic acid as the coupling component was mixed with water to prepare a dyeing solution with a concentration of 1 g / L. The pH of the dyeing solution was adjusted to 4 with acetic acid. The silk fabric was immersed in the dyeing solution at a constant temperature of 60°C for 30 minutes at a liquor ratio of 1:30. The fabric was then removed, washed with water, and dried to obtain the dyed silk fabric.

[0092] Example 6

[0093] Preparation of S1. Diazonium salt solution of m-aminobenzenesulfonic acid:

[0094] Add 20 mmol of m-aminobenzenesulfonic acid to 100 mL of water, then add dropwise a 10 wt.% sodium carbonate aqueous solution. React at room temperature until the m-aminobenzenesulfonic acid is completely dissolved to obtain a sodium m-aminobenzenesulfonate solution with a pH of 8. Add 22 mmol of sodium nitrite to the sodium m-aminobenzenesulfonate solution to obtain a mixed solution. Under stirring, add the above mixed solution dropwise to 50 mL of a 2 mol / L hydrochloric acid solution (containing 100 mmol HCl) and react at a temperature of 5 °C. After the addition is complete, continue stirring at 5 °C for 2 h to obtain a diazonium salt solution of m-aminobenzenesulfonic acid.

[0095] S2. Preparation of UV-resistant dyes with tannic acid as the coupling component:

[0096] (1) Under anaerobic conditions, 2 mmol of tannic acid was mixed with 50 mL of water, and then 40 wt.% sodium hydroxide aqueous solution was added dropwise to obtain a mixture with pH 6. Under stirring conditions, the diazonium salt solution of m-aminobenzenesulfonic acid obtained in S1 was added dropwise to the above mixture for reaction. The reaction temperature was controlled at 10 °C, and 40 wt.% sodium hydroxide aqueous solution was added to adjust the pH to 6. After the addition was completed, the reaction was stirred at 10 °C for 1.5 h to obtain the reaction solution.

[0097] (2) Add 20 mol / L hydrochloric acid solution to the reaction solution in step (1) to adjust the pH to 2, remove half of the water by rotary evaporation at 80°C, filter, and vacuum dry at 50°C to obtain the UV-resistant dye with tannic acid as the coupling component; the structural formula of the UV-resistant dye with tannic acid as the coupling component is as follows:

[0098] ;

[0099] Testing revealed that the nitrogen content in the UV-resistant dye with tannic acid as the coupling component was 7.36 wt.% (theoretical value 7.45 wt.%), and the dye exhibited a distinct color, indicating the presence of azo groups. The UV-Vis absorption spectrum of this dye is shown below. Figure 8 .

[0100] Applications of UV-resistant dyes with tannic acid as the coupling component:

[0101] A UV-resistant dye with tannic acid as the coupling component was mixed with water to prepare a dye solution with a concentration of 1 g / L. The pH of the dye solution was adjusted to 3 with acetic acid. The silk fabric was immersed in the dye solution at a constant temperature of 60°C for 30 minutes at a liquor ratio of 1:30. The fabric was then removed, washed with water, and dried to obtain the dyed silk fabric.

[0102] Example 7

[0103] Preparation of diazonium salt solution of S1,1-amino-2-naphthol-4-sulfonic acid:

[0104] Add 4 mmol of 1-amino-2-naphthol-4-sulfonic acid to 50 mL of water, then add dropwise a 4 wt.% sodium bicarbonate aqueous solution. React at room temperature until the 1-amino-2-naphthol-4-sulfonic acid is completely dissolved to obtain a sodium salt solution with a pH of 7.5. Add 4.1 mmol of sodium nitrite to the sodium salt solution to obtain a mixed solution. Under stirring, add the above mixed solution dropwise to 5 mL of a 3 mol / L hydrochloric acid solution (containing 15 mmol HCl) and react at a temperature of 10 °C. After the addition is complete, continue stirring at 10 °C for 0.5 h to obtain a diazonium salt solution of 1-amino-2-naphthol-4-sulfonic acid.

[0105] S2. Preparation of UV-resistant dyes with tannic acid as the coupling component:

[0106] (1) Under anaerobic conditions, 4 mmol of tannic acid was mixed with 4000 mL of water, and then 1 wt.% sodium bicarbonate aqueous solution was added dropwise to obtain a mixture with pH 9. Under stirring conditions, the diazonium salt solution of 1-amino-2-naphthol-4-sulfonic acid obtained in S1 was added dropwise to the above mixture for reaction. The reaction temperature was controlled at 2℃, and 1 wt.% sodium bicarbonate aqueous solution was added to adjust the pH to 8. After the addition was completed, the reaction was stirred at 5℃ for 2 h to obtain the reaction solution.

[0107] (2) Add 0.2 mol / L hydrochloric acid solution to the reaction solution in step (1) to adjust the pH to 6, remove half of the water by vacuum distillation at 50°C, filter, and dry under inert gas protection at 80°C to obtain the UV-resistant dye with tannic acid as the coupling component; the structural formula of the UV-resistant dye with tannic acid as the coupling component is as follows:

[0108] ;

[0109] Testing revealed that the nitrogen content in the UV-resistant dye with tannic acid as the coupling component was 1.60 wt.% (theoretical value 1.42 wt.%), and the dye exhibited a distinct color, indicating the presence of azo groups. The UV-Vis absorption spectrum of this dye is shown below. Figure 9 .

[0110] Applications of UV-resistant dyes with tannic acid as the coupling component:

[0111] A UV-resistant dye with tannic acid as the coupling component was mixed with water to prepare a dyeing solution with a concentration of 1 g / L. The pH of the dyeing solution was adjusted to 7 with acetic acid. The silk fabric was immersed in the dyeing solution at a constant temperature of 60°C for 30 minutes at a liquor ratio of 1:30. The fabric was then removed, washed with water, and dried to obtain the dyed silk fabric.

[0112] The apparent color depth (K / S value), rubbing fastness, washing fastness and ultraviolet protection factor (UPF value) of undyed silk fabrics and dyed silk fabrics in Examples 1-7 were tested. The test results are shown in Table 1.

[0113] Apparent color depth (K / S value): The apparent color depth (K / S value) of dyed silk fabrics was tested using a Datacolor 650 computer colorimeter (Datacolor Corporation, USA). Under the test conditions of D65 light source and 10° viewing angle, the K / S value of 4 random sites was tested and the average value was taken.

[0114] Color fastness to rubbing: Tested according to GB / T 3920-2008 "Textiles - Tests for color fastness to rubbing";

[0115] Color fastness to washing with soap: Tested according to GB / T 3921-2008 "Textiles - Tests for color fastness to washing with soap";

[0116] UPF value: Tested in accordance with GB / T 18830-2009 "Evaluation of UV protection performance of textiles".

[0117] Table 1. Test results of K / S value, color fastness to rubbing, color fastness to washing, and UPF value of undyed silk fabrics and dyed silk fabrics in Examples 1-7.

[0118]

[0119] As shown in Table 1, after dyeing silk fabrics with the UV-resistant dyes of the present invention, which use tannic acid as a coupling component, the UPF value of the dyed silk fabrics significantly increased from 8.2 to over 117 compared to the undyed silk fabrics, indicating that the dyed silk fabrics have excellent UV resistance. In addition, the color fastness to washing and rubbing of the dyed silk fabrics are both not lower than grade 4, meeting the requirements for color fastness of textiles. The K / S values ​​of the dyed silk fabrics in Examples 1-7 ranged from a minimum of 1.2 to a maximum of 4.7, indicating that using different UV-resistant dyes with tannic acid as a coupling component can produce silk fabrics with different color depths after dyeing, which can meet different usage scenarios.

Claims

1. A UV-resistant dye with tannic acid as a coupling component, characterized in that... The structural formula is as follows: ， The structural formulas for R1, R2, R3, R4, and R5 are as follows: ， Among them, the structural formulas of R6, R7 and R8 are all -H, or One of them; among them, R9 and R 10 Independently selected from one of -H, -COONa, -SO3Na, -NO2, -COOH, -SO3H, -OH, -SH, or -CN; R 11 R 12 and R 13 Independently selected from one of -H, -COONa, -SO3Na, -OH, -SO3H or -COOH, and R 11 R 12 and R 13 Cannot both be -H; When R1, R2, R3, R4 and R5 are the same, R6, R7 and R8 cannot all be -H.

2. A method for preparing the UV-resistant dye with tannic acid as a coupling component as described in claim 1, characterized in that... Includes the following steps: (1) Under stirring conditions, the diazonium salt solution of the aromatic amine derivative is added to the mixture for reaction. After the addition is complete, the reaction is stirred to obtain the reaction solution. (2) The pH of the reaction solution was adjusted, evaporated, filtered, and dried to obtain an anti-UV dye with tannic acid as the coupling component; The preparation method of the mixture in step (1) is to mix tannic acid and water evenly under anaerobic conditions and then add alkali solution to obtain the mixture.

3. The method for preparing the UV-resistant dye with tannic acid as the coupling component according to claim 2, characterized in that... The preparation method of the diazonium salt solution of the aromatic amine derivative in step (1) is either Method 1 or Method 2: Method 1: Add aromatic amine derivative and acid solution to water in sequence to react and obtain acidic salt solution of aromatic amine derivative. After cooling the acidic salt solution of aromatic amine derivative, add sodium nitrite aqueous solution and stir to react and obtain diazonium salt solution of aromatic amine derivative. Method 2: Add the aromatic amine derivative and alkaline solution to water in sequence to react and obtain an alkaline salt solution of the aromatic amine derivative. Add sodium nitrite to the alkaline salt solution of the aromatic amine derivative to obtain a mixed solution. Under stirring conditions, add the mixed solution to an acid solution to react. After the addition is complete, continue stirring to react and obtain a diazonium salt solution of the aromatic amine derivative.

4. The method for preparing the UV-resistant dye with tannic acid as the coupling component according to claim 3, characterized in that... In Method 1, the aromatic amine derivative includes one of the following: aniline, p-nitroaniline, m-nitroaniline, 2,4-dinitroaniline, p-aminophenol, m-aminophenol, 2-amino-1,4-dihydroxybenzene, 2-amino-1,3-benzenediol, 4-aminobenzenethiophenol, 3-aminobenzenethiophenol, p-cyanoaniline, m-cyanoaniline, 1-amino-2-naphthol, or 8-amino-2-naphthol; the ratio of water to the aromatic amine derivative is 2-100:1, where water is expressed in mL and the aromatic amine derivative in mmol; the reaction... The reaction is carried out at room temperature until the aromatic amine derivative is completely dissolved. The cooling temperature is 0-10℃, the concentration of the sodium nitrite aqueous solution is 10-50 wt.%, the molar ratio of the aromatic amine derivative to sodium nitrite in the sodium nitrite aqueous solution is 1:1-1.1, the stirring time is 0.5-5 h, the stirring temperature is 0-10℃, the acid solution is hydrochloric acid solution or sulfuric acid solution, the hydrogen ion concentration in the acid solution is 0.2-20 mol / L, and the molar ratio of the aromatic amine derivative to hydrogen ions in the acid solution is 1:2-10.

5. The method for preparing the UV-resistant dye with tannic acid as the coupling component according to claim 3, characterized in that... In Method 2, the aromatic amine derivatives include one of the following: p-aminobenzoic acid, m-aminobenzoic acid, 4-aminophthalic acid, p-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, 2,4-disulfonic acid aniline, 4-amino-1-naphthalenesulfonic acid, 5-amino-1-naphthalenesulfonic acid, 8-amino-2-naphthalenesulfonic acid, 2-amino-5,7-naphthalenedisulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 1-amino-8-naphthol-3,6-disulfonic acid, 2-amino-5-naphthol-7-sulfonic acid, or 2-amino-8-naphthol-6-sulfonic acid.

6. The method for preparing the UV-resistant dye with tannic acid as the coupling component according to claim 3, characterized in that... In Method 2, the ratio of water to aromatic amine derivative is 2-100:1, where water is expressed in mL and aromatic amine derivative in mmol. The reaction is carried out at room temperature until the aromatic amine derivative is completely dissolved. The pH of the alkaline salt solution of the aromatic amine derivative is 7-8, and the molar ratio of aromatic amine derivative to sodium nitrite is 1:1-1.

1. The reaction temperature is 0-10℃ when the mixed solution is added to the acid solution, and the stirring time is 0.5-5h. The alkaline solution is one or more of sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, or sodium hydroxide aqueous solution, and the concentration of the alkaline solution is 1-40 wt.%. The acid solution is hydrochloric acid solution or sulfuric acid solution, and the molar ratio of hydrogen ions in the aromatic amine derivative to the acid solution is 1:2-10. The hydrogen ion concentration in the acid solution is 0.2-20 mol / L.

7. The method for preparing the UV-resistant dye with tannic acid as the coupling component according to claim 2, characterized in that... In step (1), the reaction temperature is controlled at 0-10℃ and an alkaline solution is added to adjust the pH to 6-9. The alkaline solution is one of sodium carbonate aqueous solution, sodium bicarbonate aqueous solution or sodium hydroxide aqueous solution, and the concentration of the alkaline solution is 1-40 wt.%. The temperature of the stirring reaction is 0-10℃ and the stirring reaction time is 0.5-2h.

8. The method for preparing the UV-resistant dye with tannic acid as the coupling component according to claim 2, characterized in that... In step (1), the ratio of tannic acid to water is 1-40:1, where tannic acid is expressed in mmol and water in L; the molar ratio of tannic acid to the diazonium salt of the aromatic amine derivative in the diazonium salt solution is 1:1-10; the pH of the mixture is 6-9; the alkaline solution is one or more of sodium bicarbonate aqueous solution, sodium carbonate aqueous solution or sodium hydroxide aqueous solution, and the concentration of the alkaline solution is 1-40 wt.%.

9. The method for preparing the UV-resistant dye with tannic acid as the coupling component according to claim 2, characterized in that... In step (2), pH is adjusted by adding an acid solution to adjust the pH to 2-6. The acid solution is hydrochloric acid solution or sulfuric acid solution, and the hydrogen ion concentration in the acid solution is 0.2-20 mol / L. Evaporation is carried out by vacuum distillation or rotary evaporation, and the evaporation temperature is 50-80℃. Drying is carried out by vacuum drying or oxygen-free drying under inert gas protection, and the drying temperature is 50-80℃.

10. The application of the UV-resistant dye with tannic acid as a coupling component as described in claim 1, characterized in that... Application in the dyeing of silk textiles.

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