Weakly alkaline ph reduction dyeing method using n-acetyl indigoidine and use thereof

Abstract

The present application relates to the technical field of dyeing and finishing, and in particular to a weakly alkaline pH reduction dyeing method using N-acetyl indigoidine and a use thereof. It is found in the present application that N-acetyl indigoidine is a novel vat dye, meets the safety assessment requirements for textile dyes, and can be applied to textile dyeing. The present application discloses a weakly alkaline pH reduction dyeing method using N-acetyl indigoidine for textiles; the dyed textiles have significantly improved color depth, brighter color, and good color fastness, and meet the national standards for textile dyeing; and the content of reducing agents is reduced, thereby reducing environmental pollution.

Description

Weak alkaline pH vat dyeing method using N-acetyl indigo and application thereof TECHNICAL FIELD

[0001] The present application relates to the dyeing and finishing technical field, and in particular to a weak alkaline pH vat dyeing method using N-acetyl indigo and application thereof. BACKGROUND

[0002] Blue is one of the common colors in daily life. Indigo was extracted from plants very early and used in the fields of textiles and porcelain. The blue pigment extracted from plants belongs to organic pigment and is more compatible with the human body, and is widely loved as a dye for fabrics. With the increasing demand for blue dyes, traditional plant extraction cannot provide enough blue pigment, so in the 19th century, people prepared synthetic indigo through chemical synthesis, which gradually replaced natural blue pigment and became the most commonly used blue dye. However, this chemical synthesis method not only meets the demand for indigo, but also uses a large amount of chemical raw materials, causing damage and pollution to the environment. As a water-insoluble vat dye, indigo needs to be reduced to a soluble leuco sodium salt by adding a reducing agent under strong alkaline conditions, and then it can be dissolved to dye fabrics. The general dyeing process of indigo in industry is the caustic soda and sodium hydrosulfite method, which requires a large amount of sodium hydrosulfite (15 times the mass of indigo) and caustic soda (5 times the mass of indigo, pH>13) to prepare the dyeing solution, which not only causes great pollution to the environment, but also damages the printed and dyed fabrics due to the strong alkalinity of the dyeing solution. In recent years, with increasing emphasis on environmental and energy issues, people tend to pursue sustainable and environmentally friendly methods to produce dyes, and this synthetic indigo also needs to be replaced by some other natural blue pigment.

[0003] Common natural blue pigments include gardenia blue (iridoid derivative blue pigment), phycocyanin, indigo pigment, oyster green pigment and anthocyanin, which are mainly extracted from plants and microorganisms. Among them, plant extraction is limited by factors such as slow plant growth, low pigment content, and complex plant components, and cannot be produced on a large scale; in contrast, microbial fermentation has a short cycle, and the product is single after strain modification, so that relatively pure products can be obtained through simple post-processing methods. For example, when L-glutamine is used as a substrate for microbial fermentation, two molecules of glutamine are catalyzed by indigo synthase to generate the blue pigment Indigoidine (indigo). However, indigo still uses strong alkaline vat dyeing method, although the amount is reduced, but still needs to use about 3 times the mass of sodium hydrosulfite and 3 times the mass of indigo, and the required pH is about 11. The strong alkaline conditions required for indigo dyeing solution still have a certain destructive effect on the environment and textiles.

[0004] In the early stage, the applicant disclosed that the expression of violan synthase and 4'-phosphopantetheinyl transferase catalyzed the biosynthesis of N-acetyl violan from glutamine and N-acetyl glutamine in E. coli, C. glutamicum, S. cerevisiae and Streptomyces, and there is no related report on the weak alkaline pH reduction dyeing method using N-acetyl violan.

[0005] SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art and provide a weak alkaline pH reduction dyeing method using N-acetyl violan and its application. The present application proposes that N-acetyl violan is a new type of fabric reduction dye. The weak alkaline pH reduction dyeing method is used for fabric dyeing. The obtained dyed fabric meets the national standard for fabric dyeing, the color depth is significantly improved, the color is brighter, the color fastness is good, and the alkali content is reduced, and the environmental pollution is reduced.

[0007] To achieve the above purpose, the technical scheme adopted by the present application is:

[0008] The present application provides a weak alkaline pH reduction dyeing method using N-acetyl violan, comprising the following steps:

[0009] S1, weigh N-acetyl violan and dissolve it in water to form an N-acetyl violan solution, add a reducing agent to the N-acetyl violan solution and stir to reduce, obtain a dyeing liquid, adjust the pH of the dyeing liquid to 7.0-8.0, and place it for reduction to obtain an N-acetyl violan dyeing liquid;

[0010] S2, immerse the textile in the N-acetyl violan dyeing liquid obtained in step S1 for dyeing, dry and oxidize, wash, and dry;

[0011] S3, the textile treated in step S2 is subjected to soaping treatment and dried to obtain a dyed textile.

[0012] The present application determines that N-acetyl violan is a green and safe reduction dye with a product naturalness of 97% through the qualitative detection of dyes, safety detection of dyes, USDA product naturalness detection, etc. mentioned in ISO16373-1:2015 (General principles of testing coloured textiles for dyestuff identification).

[0013] N-acetyl indigo belongs to the derivatives of indigo, and is the amino acylated product of L-glutamine in the synthesis of indigo in microorganisms. The presence of acetyl group can further reduce the amount of alkali required (the pH of the dyeing solution is closer to neutral), reduce the polarity of N-acetyl indigo, and thus the dyeing fabric is not easy to be washed off, which helps to increase the color fastness of the dyeing. As a vat dye, N-acetyl indigo is quite different from traditional vat dye indigo in structure. N-acetyl indigo has more amino groups than indigo, which makes the water solubility of N-acetyl indigo in the leuco form relatively better, which helps to reduce the amount of reducing agent during reduction. In addition, due to the presence of amino acyl group, the polarity is reduced, and after dyeing on the fabric, it is more difficult to be washed off by water, which increases the color fastness of the dyeing.

[0014] The present application applies the biosynthetic N-acetyl indigo, a new natural blue pigment, to fabric dyes, and establishes a weak alkali pH reduction dyeing method for N-acetyl indigo for textiles, in order to reduce environmental pollution and reduce production costs. The main quality indicators such as color, depth and color fastness of the obtained N-acetyl indigo dyed textiles reach or exceed the quality level of the currently available indigo or indigo dyed fabrics.

[0015] Using the weak alkali pH reduction dyeing method of the present application, the obtained dyed textiles meet the national standards for fabric dyeing, the color depth of the textiles is improved, the color is brighter, and the color fastness is good. Using DMSO to dissolve the pigment on the textiles, liquid phase detection proves that the dye of the dyed fabric is N-acetyl indigo.

[0016] As a preferred embodiment of the weak alkali pH reduction dyeing method using N-acetyl indigo described in the present application, the mass ratio of the reducing agent to N-acetyl indigo in step S1 is (0.5-3):1.

[0017] As a preferred embodiment of the weak alkali pH reduction dyeing method using N-acetyl indigo described in the present application, the mass ratio of the reducing agent to N-acetyl indigo is (1-2):1.

[0018] Using the reducing agent and N-acetyl indigo in the above mass ratio can ensure that most of the N-acetyl indigo is reduced to leuco form, and the dyeing effect is obvious. When the mass of N-acetyl indigo is too much, the dyeing deepening is not obvious. When the reducing agent is too much, N-acetyl indigo is over-reduced and is not easy to oxidize back, and the pollutants in the dyeing waste liquid are increased.

[0019] As a preferred embodiment of the weak alkali pH reduction dyeing method using N-acetyl indigo described in the present application, the reducing agent includes one of sodium hydrosulfite, sodium sulfide and sodium dithionite.

[0020] Preferably, the reducing agent is sodium dithionite, i.e. sodium hydrosulfite.

[0021] The weak alkaline pH reduction dyeing method using N-acetyl indigo blue can reduce the amount of reducing agent such as sodium hydrosulfite, and increase the color fastness, which is helpful for textile dyeing.

[0022] In the step S1, the pH of the dyeing solution is adjusted to 7.0-8.0, preferably 7.5, by using an alkali solution or an acid solution.

[0023] The alkali solution includes one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, and sodium bicarbonate; preferably, the alkali solution is sodium hydroxide.

[0024] The acid solution includes one of sulfuric acid, hydrochloric acid, citric acid, acetic acid, and carbonic acid; preferably, the acid solution is citric acid.

[0025] In the step S1, the reduction time is 5-60 min, preferably 10-30 min.

[0026] If the reduction time is too short, the reduction is not sufficient, and if the reduction time is too long, the sodium hydrosulfite is ineffective, both of which reduce the dye uptake of N-acetyl indigo blue.

[0027] In the step S2, the dyeing temperature is 20-60℃, and the dyeing time is 5-20 min; the air oxidation time is 3-10 min.

[0028] If the dyeing temperature is higher than 60℃, N-acetyl indigo blue is damaged, and if the dyeing temperature is lower than 20℃, N-acetyl indigo blue dyeing solution cannot penetrate into the fabric.

[0029] If the air oxidation time is less than 3 min, the color depth of the fabric is reduced after washing; if the air oxidation time is more than 10 min, color spots that are not easy to wash off appear on the surface of the fabric, resulting in uneven dyeing.

[0030] In the step S2, the mass ratio of N-acetyl indigo blue dyeing solution to textile is (10-100):1.

[0031] In the step S3, the soaping bath ratio is 10:1, the soaping temperature is 20-60℃, and the soaping time is 5-20 min.

[0032] The soap-to-bath ratio is a term used in textile dyeing and finishing, referring to the ratio of the mass of the textile to the mass of the N-acetylglucosamine dyeing solution. In practical applications, the density of the dyeing solution is often treated as 1.

[0033] In the technical solution of this application, soaping can remove the floating color from the surface of textiles, which is beneficial to increasing the color fastness of dyeing.

[0034] This application provides a milder, weakly alkaline pH reduction staining method with low sodium hydrosulfite content (0.5-3 times the mass of N-acetylglucosamine blue), low alkali content (pH 7.0-8.0).

[0035] As a preferred embodiment of the weakly alkaline pH reduction dyeing method using N-acetylsmuth blue described in this application, the textile includes at least one of plant fibers, protein fibers, regenerated fibers, and chemical fibers.

[0036] Preferably, the plant fiber includes cotton or linen, the protein fiber includes silk or wool, the regenerated fiber includes modal or lyocell, and the chemical fiber includes one of polyester, nylon, and acrylic.

[0037] This application also provides the application of N-acetylglucosamine as a dye in fabric dyeing and reduction, wherein the molecular formula of N-acetylglucosamine is C 12 H 10 N4O5, the structural formula is shown in formula (I);

[0038] N-acetylglucosamine is a new type of vat dye for fabrics. N-acetylglucosamine products have a naturalness of 97%, are identified as vat dyes, and have passed dye safety tests to prove their green and safe nature.

[0039] This application also includes quality assessment of the dyed textiles. A colorimeter is used to measure and calculate the K / S value to characterize the depth of color in the dyed textiles. The color fastness to rubbing and color fastness to washing of the dyed textiles are tested according to GB / T3920—2008 "Textiles - Tests for Color Fastness to Rubbing" and GB / T3921—2008 "Textiles - Tests for Color Fastness to Washing". Product quality testing shows that the main quality indicators of N-acetylglucosamine dyed textiles obtained under the optimized conditions of the weakly alkaline pH reduction dyeing method, such as color, color depth, and color fastness, meet or exceed the quality level of currently available indigo or indigo dyed textiles; while the main quality indicators of indigo or indigo dyed textiles obtained under the optimized conditions of the weakly alkaline pH reduction dyeing method do not meet the quality standards for dyed textiles.

[0040] Under the preferred conditions of weak alkaline pH vat dyeing, the N-acetyl indigo dyed textile obtained is cut into 5mm diameter pieces with a puncher, immersed in 1mL of DMSO to dissolve the pigment on the textile, and then the blue pigment dissolved by immersion is proved to be N-acetyl indigo by liquid analysis comparison. Small pieces of N-acetyl indigo dyed textile, indigo dyed textile and blue dyed textile are immersed and dissolved in DMSO respectively, and the obtained solutions are scanned by full wavelength spectrum, the maximum absorption wavelength of N-acetyl indigo dyed textile solution is about 584±2nm, the maximum absorption wavelength of indigo dyed textile solution is about 600±2nm, and the maximum absorption wavelength of indigo dyed textile solution is about 610±2nm, which can be used as a method for distinguishing the three kinds of dyed textiles.

[0041] Compared with the prior art, the application has the following beneficial effects:

[0042] The application provides a weak alkaline pH vat dyeing method of N-acetyl indigo and application thereof, the N-acetyl indigo used in the application can be used as a new vat dye, meets the safety identification requirements of textile dyes, and can be applied to textile dyeing; the application establishes a vat dyeing method of N-acetyl indigo for textiles, the dyed textiles have significantly improved color depth, brighter color, good color fastness, meet the national standards for textile dyeing, and reduce the content of alkali and environmental pollution, and meet different market demands. BRIEF DESCRIPTION OF DRAWINGS

[0043] Fig. 1 is a molecular structure diagram of indigo, indigo blue and N-acetyl indigo (Fig. 1-A is indigo; Fig. 1-B is indigo blue; Fig. 1-C is N-acetyl indigo);

[0044] Fig. 2 is an experimental diagram of identifying dye types of N-acetyl indigo;

[0045] Fig. 3 is N-acetyl indigo natural degree certification;

[0046] Fig. 4 is a display diagram of dyed cotton fabrics of examples 2-6 and comparative examples 1-8 (1 in the figure is an undyed fabric piece, 2-7 in the figure are dyeing diagrams of N-acetyl indigo examples 2-6 and comparative examples 1 and 2, 8 and 9 in the figure are dyeing diagrams of indigo blue comparative examples 3 and 4, 10 and 11 in the figure are dyeing diagrams of indigo comparative examples 5 and 6, and 12 and 13 in the figure are dyeing diagrams of N-acetyl indigo comparative examples 7 and 8);

[0047] Fig. 5 is a liquid chromatogram and ultraviolet full wavelength scanning diagram of three pigments dissolved on the fabric piece (Fig. 5-A is a liquid chromatogram of N-acetyl indigo; Fig. 5-B is a liquid chromatogram of indigo blue; Fig. 5-C is a liquid chromatogram of indigo; and Fig. 5-D is a full wavelength spectrum scanning diagram corresponding to the three pigments). DETAILED DESCRIPTION

[0048] For better illustrating the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with the drawings and specific embodiments.

[0049] In the following examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0050] The N-acetyl indigo and indigo used in the following examples are obtained by fermentation developed by our company (Nanjing Hugu Life Biotechnology Co., Ltd.).

[0051] The safety report of N-acetyl indigo of the present application is provided by Shaoxing Quality and Technical Supervision Testing Institute, the dye type qualitative analysis is determined by the method provided in International Standard ISO 16373-1:2015 according to the inventors, and the product naturalness certification of the United States Department of Agriculture (USDA BIOPREFERRED) is passed.

[0052] From Example 2 to Example 7, different conditions were selected for dyeing test with N-acetyl indigo; Comparative Example 1 and Comparative Example 2 were dyeing tests of indigo; Comparative Example 3 and Comparative Example 4 were dyeing tests of indigo. Example 8: Quality testing was performed on the dyed cloth pieces of Examples 2-7 and Comparative Examples 1-4. K / S value was used to represent the depth of the dyed cotton fabric, and the rubbing fastness and soaping fastness of the cotton fabric were tested according to GB / T3920-2008 “Textile Color Fastness Test Rubbing Fastness” and GB / T3921-2008 “Textile Color Fastness Test Soaping Fastness”. Example 9: The dyed cloth pieces in Example 2, Comparative Example 1 and Comparative Example 3 were immersed in DMSO to dissolve the pigments, and the solution was scanned for full wavelength spectrum to compare the maximum absorption wavelength of the three blue pigments.

[0053] The molecular structure diagrams of indigo, indigo, and N-acetyl indigo mentioned in the following examples and comparative examples are shown in Figure 1 (Figure 1-A is indigo; Figure 1-B is indigo; Figure 1-C is N-acetyl indigo).

[0054] Example 1, N-acetyl indigo dye type, safety and naturalness identification

[0055] The dye type of N-acetyl observed blue was determined by the dye qualitative detection method mentioned in ISO 16373-1:2015 (General principles of testing coloured textiles for dyestuff identification). Then the obtained N-acetyl observed blue pure product was sent to Shaoxing Quality and Technical Supervision Testing Institute for dye safety detection, mainly detecting whether N-acetyl observed blue contains harmful aromatic amines, heavy metal content, harmful solvents, etc. In addition, the N-acetyl observed blue pure product was also sent to the United States Department of Agriculture (USDA) for product naturalness detection.

[0056] Specifically:

[0057] Since N-acetyl observed blue presents a deep blue color in solution, the present applicant refers to the method provided in international standard ISO 16373-1:2015 to identify the dye type of N-acetyl observed blue, and the specific experimental steps are shown in (A-F), and the experimental results are shown in FIG. 2 (FIG. 2-A to FIG. 2-F).

[0058] A. 0.2 g of N-acetyl observed blue sample was placed in boiling 10 mL 1% ammonia solution for 1 minute, and after centrifugation at 13000 r / min for 5 min, a light purple color was generated in the solution, and a blue precipitate was generated at the bottom of the test tube, indicating that N-acetyl observed blue was not dissolved in 1% ammonia water, so observed blue is not an acid dye;

[0059] B. 0.2 g of N-acetyl observed blue sample was placed in boiling 5% acetic acid for 1 min, and the solution color did not change significantly, and after centrifugation, a large amount of observed blue precipitate was generated, and the supernatant had no color change, so N-acetyl observed blue is not a basic dye.

[0060] C. 0.2 g of N-acetyl observed blue sample was directly added to 5% sodium hydroxide, and then centrifuged at 13000 r / min for 5 min. Because N-acetyl observed blue will change when pH>12, the supernatant of the solution is light brown, but there is still a precipitate, and N-acetyl observed blue is basically insoluble in 5% sodium hydroxide, so N-acetyl observed blue is neither a direct dye nor an active dye.

[0061] D. Since N-acetyl observed blue will change when pH>12, the N-acetyl observed blue sample was treated with a pH 11 aqueous solution instead of a 20% sodium hydroxide solution, and then water and sodium hydrosulfite were added, the test tube was shaken, the solution color turned gray and then oxidized to blue, and the solution color did not change after further adding cold and diluted sodium hypochlorite solution, so N-acetyl observed blue is a reducing dye.

[0062] E. 0.2g of N-acetyl indigo was treated with 16% hydrochloric acid, after heating and cooling, magnesium ribbon was added, the color of N-acetyl indigo changed in 16% hydrochloric acid, but it did not turn black when tested with lead acetate paper, and no hydrogen sulfide odor gas was produced, so N-acetyl indigo is not a sulfur dye.

[0063] F. A small amount of N-acetyl indigo sample was heated with concentrated sulfuric acid for a few seconds, and poured into cold water, at this time the solution was blue in color, and no dark green color was produced, so N-acetyl indigo is not aniline black dye.

[0064] In summary, the identification result is that N-acetyl indigo, a new substance, is a vat dye. The most commonly used blue vat dye is synthetic indigo, which is synthesized by chemical method, and the raw materials and intermediates contain a large amount of benzene acetic acid, toluene, β-aniline, anthranilic acid and other substances, which will cause environmental pollution to a great extent. The safety of N-acetyl indigo, a vat dye, was detected, and the test results issued by Shaoxing Quality and Technical Supervision Testing Institute are shown in Table 1. Since N-acetyl indigo is fermented by microorganisms, harmful aromatic amines, harmful solvents and other substances are not used in the culture process, so the final test results also show that N-acetyl indigo does not contain such substances.

[0065] Table 1

[0066] In addition, the N-acetyl indigo produced by the applicant is certified by the BioPreferred Program managed by the U.S. Department of Agriculture (USDA), and the natural degree of the product reaches 97% (Figure 3). Therefore, N-acetyl indigo has the characteristics of being more natural, environmentally friendly, and green and safe.

[0067] Example 2

[0068] The present embodiment provides a weak alkaline pH vat dyeing method using N-acetyl indigo, comprising the following steps:

[0069] (1) Preparation of N-acetyl indigo dyeing solution: 1g of N-acetyl indigo powder was dissolved in 1L of pure water to obtain an N-acetyl indigo solution, 0.5g of sodium hydrosulfite was added to the N-acetyl indigo and stirred to reduce, then the pH of the dyeing solution was adjusted to 7.0 with lye (sodium hydroxide), and the solution was sealed and reduced for 5min to obtain a 1g / L N-acetyl indigo dyeing solution;

[0070] (2) Dyeing of textile: 50 mL of the N-acetyloxyblue dyeing solution prepared in (1) above was taken and cotton cloth was immersed in the dyeing solution at a bath ratio (mass of N-acetyloxyblue dyeing solution : mass of cotton cloth) of 10:1. The cotton cloth was taken out after dyeing at 20°C for 5 min, and was air-dried and oxidized for 3 min. Then, the cotton cloth was washed with water and was air-dried.

[0071] (3) Soaping process: the cotton cloth dyed in (2) above was subjected to soaping treatment at a soaping bath ratio of 10:1 and at a soaping temperature of 20°C for 5 min. The cotton cloth was taken out and was air-dried to obtain dyed cotton cloth (2 in Fig. 4, 1 in Fig. 4 is a control undyed cloth piece).

[0072] Example 3

[0073] The present example provides a weak alkaline pH vat dyeing method using N-acetyloxyblue, which comprises the following steps:

[0074] (1) Preparation of N-acetyloxyblue dyeing solution: 2 g of N-acetyloxyblue powder was dissolved in 1 L of pure water to obtain an N-acetyloxyblue solution. 2 g of sodium hydrosulfite (sodium dithionite) was added to the N-acetyloxyblue solution and was stirred to reduce. Then, an alkali solution (sodium hydroxide) was used to adjust the pH of the dyeing solution to 7.5, and the solution was sealed and reduced for 15 min to obtain a 2 g / L N-acetyloxyblue dyeing solution.

[0075] (2) Dyeing of textile: 50 mL of the N-acetyloxyblue dyeing solution prepared in (1) above was taken and cotton cloth was immersed in the dyeing solution at a bath ratio (mass of N-acetyloxyblue dyeing solution : mass of cotton cloth) of 10:1. The cotton cloth was taken out after dyeing at 20°C for 5 min, and was air-dried and oxidized for 3 min. Then, the cotton cloth was washed with water and was air-dried.

[0076] (3) Soaping process: the cotton cloth dyed in (2) above was subjected to soaping treatment at a soaping bath ratio of 10:1 and at a soaping temperature of 20°C for 5 min. The cotton cloth was taken out and was air-dried to obtain dyed cotton cloth (2 in Fig. 4, 1 in Fig. 4 is a control undyed cloth piece).

[0077] Example 4

[0078] The present example provides a weak alkaline pH vat dyeing method using N-acetyloxyblue, which comprises the following steps:

[0079] (1) Preparation of N-acetyloxyblue dyeing solution: 2 g of N-acetyloxyblue powder was dissolved in 1 L of pure water to obtain an N-acetyloxyblue solution. 2 g of sodium hydrosulfite (sodium dithionite) was added to the N-acetyloxyblue solution and was stirred to reduce. Then, an alkali solution (sodium hydroxide) was used to adjust the pH of the dyeing solution to 7.5, and the solution was sealed and reduced for 15 min to obtain a 2 g / L N-acetyloxyblue dyeing solution.

[0080] (2) Dyeing of textile: Take 250 mL of N-acetyloxyblue dyeing solution from the above (1), soak the cotton cloth according to the bath ratio (mass of N-acetyloxyblue dyeing solution: mass of dyed cotton cloth) 50:1, take out after dyeing at 45°C for 20 min, air oxidation for 10 min, then wash with water, and dry;

[0081] (3) Soaping process: the dyed cotton cloth in the above (2) is subjected to soaping treatment, soaping bath ratio 10:1, soaping temperature 45°C, soaping time 20 min, and the dyed cotton cloth (4 in FIG. 4) can be obtained after taking out and drying.

[0082] Example 5

[0083] The present embodiment provides a weak alkaline pH reduction dyeing method using N-acetyloxyblue, comprising the following steps:

[0084] (1) Preparation of N-acetyloxyblue dyeing solution: weigh 1 g of N-acetyloxyblue powder and dissolve it in 1 L of pure water to obtain an N-acetyloxyblue solution, weigh 2 g of sodium dithionite (sodium hydrosulfite) and add it to the N-acetyloxyblue, stir well to reduce, then adjust the pH of the dyeing solution to 7.5 with alkali (sodium hydroxide), seal and reduce for 30 min, and then 2 g / L of N-acetyloxyblue dyeing solution can be obtained;

[0085] (2) Dyeing of textile: Take 50 mL of N-acetyloxyblue dyeing solution from the above (1), soak the cotton cloth according to the bath ratio (mass of N-acetyloxyblue dyeing solution: mass of dyed cotton cloth) 10:1, take out after dyeing at 25°C for 10 min, air oxidation for 5 min, then wash with water, and dry;

[0086] (3) Soaping process: the dyed cotton cloth in the above (2) is subjected to soaping treatment, soaping bath ratio 10:1, soaping temperature 25°C, soaping time 10 min, and the dyed cotton cloth (5 in FIG. 4) can be obtained after taking out and drying.

[0087] Example 6

[0088] The present embodiment provides a weak alkaline pH reduction dyeing method using N-acetyloxyblue, comprising the following steps:

[0089] (1) Preparation of N-acetyloxyblue dyeing solution: weigh 2 g of N-acetyloxyblue powder and dissolve it in 1 L of pure water to obtain an N-acetyloxyblue solution, weigh 2 g of sodium dithionite (sodium hydrosulfite) and add it to the N-acetyloxyblue, stir well to reduce, then adjust the pH of the dyeing solution to 7.5 with alkali (sodium hydroxide), seal and reduce for 10 min, and then 2 g / L of N-acetyloxyblue dyeing solution can be obtained;

[0090] (2) Dyeing of textile: 50 mL of the N-acetyl sky blue dyeing solution from the above (1) was taken, cotton cloth was soaked according to the bath ratio (mass of N-acetyl sky blue dyeing solution : mass of cotton cloth) 10:1, and was taken out after dyeing at 60°C for 10 min, was air-dried and oxidized for 5 min, and then was washed with water and was air-dried;

[0091] (3) Soaping process: the cotton cloth dyed in the above (2) was subjected to soaping treatment, the soaping bath ratio was 10:1, the soaping temperature was 60°C, the soaping time was 10 min, and the dyed cotton cloth (6 in FIG. 4) was obtained after being taken out and air-dried.

[0092] Comparative Example 1

[0093] This comparative example used the optimal conditions of the strong alkali reduction dyeing method of sky blue to reduce dye N-acetyl sky blue.

[0094] This comparative example provided a strong alkali reduction dyeing method using N-acetyl sky blue, including the following steps:

[0095] (1) Preparation of N-acetyl sky blue dyeing solution: 2 g of N-acetyl sky blue powder was dissolved in 1 L of pure water to obtain an N-acetyl sky blue solution, 4 g of sodium hydrosulfite (sodium dithionite) was added to the N-acetyl sky blue and was stirred to reduce, then an alkali solution (sodium hydroxide) was used to adjust the pH of the dyeing solution to 10.0, and the solution was sealed and reduced for 15 min, thereby obtaining a 2 g / L N-acetyl sky blue dyeing solution;

[0096] (2) Dyeing of textile: 50 mL of the N-acetyl sky blue dyeing solution from the above (1) was taken, cotton cloth was soaked according to the bath ratio (mass of N-acetyl sky blue dyeing solution : mass of cotton cloth) 10:1, and was taken out after dyeing at 60°C for 10 min, was air-dried and oxidized for 5 min, and then was washed with water and was air-dried;

[0097] (3) Soaping process: the cotton cloth dyed in the above (2) was subjected to soaping treatment, the soaping bath ratio was 10:1, the soaping temperature was 60°C, the soaping time was 10 min, and the dyed cotton cloth (6 in FIG. 4) was obtained after being taken out and air-dried.

[0098] Comparative Example 2

[0099] This comparative example used the general strong alkali reduction method of indigo dyeing to reduce dye N-acetyl sky blue.

[0100] This comparative example provided a strong alkali reduction dyeing method using N-acetyl sky blue, including the following steps:

[0101] (1) Preparation of N-acetyl indigo dyeing solution: 2 g of N-acetyl indigo powder was dissolved in 1 L of pure water to obtain an N-acetyl indigo solution, 30 g of sodium dithionite (sodium hydrosulfite) was added to the N-acetyl indigo solution and stirred to reduce, then 10 g of caustic soda was added, at this time the pH was about 12.8, and the reduction was sealed and placed for 20 min, to obtain 2 g / L of N-acetyl indigo dyeing solution;

[0102] (2) Dyeing of textiles: 50 mL of the dyeing solution from (1) above was taken, and cotton cloth was soaked in it at a bath ratio (mass of dyeing solution: mass of dyed cloth) of 10:1, dyed at 25°C for 10 min, then taken out, oxidized by air drying for 5 min, washed, and dried;

[0103] (3) Soaping process: the dyed cotton cloth from (2) above was subjected to soaping treatment at a soaping bath ratio of 10:1, a soaping temperature of 25°C, and a soaping time of 10 min, and then taken out and dried, to obtain dyed cotton cloth (8 in FIG. 4).

[0104] Comparative Example 3

[0105] In this comparative example, indigo was used as a comparison. Indigo (existing) was also developed by the company (Nanjing Hegot Life Biotechnology Co., Ltd.) through fermentation and was available for purchase on the company's website. The best conditions for indigo dyeing at present are 2 times of sodium dithionite reduction, dyeing at pH 10.0, which is a strong alkali reduction dyeing method.

[0106] (1) Preparation of indigo dyeing solution: 2 g of indigo powder was dissolved in 1 L of pure water to obtain an indigo solution, 4 g of sodium dithionite (sodium hydrosulfite) was added to the indigo and stirred to reduce, then the pH of the dyeing solution was adjusted to 10.0 with a lye (sodium hydroxide), and the reduction was sealed and placed for 15 min, to obtain 2 g / L of indigo dyeing solution;

[0107] (2) Dyeing of cotton cloth: 50 mL of the indigo dyeing solution from (1) above was taken, and cloth was soaked in it at a bath ratio (mass of indigo dyeing solution: mass of dyed cloth) of 10:1, dyed at 25°C for 10 min, then taken out, oxidized by air drying for 5 min, washed, and dried;

[0108] (3) Soaping process: the dyed cotton cloth from (2) above was subjected to soaping treatment at a soaping bath ratio of 10:1, a soaping temperature of 25°C, and a soaping time of 10 min, and then taken out and dried, to obtain dyed cotton cloth (9 in FIG. 4).

[0109] Comparative Example 4

[0110] The present embodiment selects Guanlan as a comparison. Guanlan (existing) is also a self-developed fermentation product of the company (Nanjing Hegot Life Biotechnology Co., Ltd.), which can be purchased from the company's official website. The dyeing method is carried out according to the optimization condition of the above-mentioned N-acetyl Guanlan weak alkali pH reduction dyeing method (Example 3).

[0111] (1) Preparation of Guanlan dyeing solution: 2 g of Guanlan powder was dissolved in 1 L of pure water to obtain a Guanlan solution. 2 g of sodium hydrosulfite (hyposulfite) was added to the Guanlan solution and stirred thoroughly to reduce, then an alkali solution (sodium hydroxide) was used to adjust the pH of the dyeing solution to 7.5, and the solution was sealed and reduced for 15 min. A 2 g / L Guanlan dyeing solution was obtained.

[0112] (2) Dyeing of cotton fabric: 50 mL of the Guanlan dyeing solution from (1) above was used to soak the fabric according to a bath ratio (mass of dyeing solution: mass of fabric) of 10:1. The fabric was dyed at 25°C for 10 min, then taken out, oxidized by air drying for 5 min, washed, and dried.

[0113] (3) Soaping process: the dyed cotton fabric from (2) above was subjected to a soaping process with a bath ratio of 10:1, a soaping temperature of 25°C, and a soaping time of 10 min. The fabric was taken out and dried to obtain the dyed cotton fabric (10 in Figure 4).

[0114] Comparative Example 5

[0115] In this comparative example, commercial indigo was used as a comparison. The commercial indigo was purchased from Luon Reagent. The dyeing method was carried out according to the general strong alkali reduction dyeing method for indigo, i.e., 15 times the mass of indigo was reduced with sodium hydrosulfite, and 5 times the mass of indigo was reduced with caustic soda.

[0116] (1) Preparation of indigo dyeing solution: 2 g of indigo powder was dissolved in 1 L of pure water to obtain an indigo solution. 30 g of sodium hydrosulfite (hyposulfite) was added to the indigo solution and stirred thoroughly to reduce, then 10 g of caustic soda was added. At this time, the pH was about 13.2, and the solution was sealed and reduced for 20 min. A 2 g / L indigo dyeing solution was obtained.

[0117] (2) Dyeing of cotton fabric: 50 mL of the dyeing solution from (1) above was used to soak the cotton fabric according to a bath ratio (mass of dyeing solution: mass of fabric) of 10:1. The fabric was dyed at 25°C for 10 min, then taken out, oxidized by air drying for 5 min, washed, and dried.

[0118] (3) Soaping process: the dyed cotton fabric from (2) above was subjected to a soaping process with a bath ratio of 10:1, a soaping temperature of 25°C, and a soaping time of 10 min. The fabric was taken out and dried to obtain the dyed cotton fabric (11 in Figure 4).

[0119] Comparative Example 6

[0120] The commercial indigo was used as a comparison, which was purchased from Rongen Reagent. The dyeing method was carried out according to the optimized condition of Example 3.

[0121] (1) Preparation of indigo dyeing solution: 2 g of indigo powder was dissolved in 1 L of pure water to obtain an indigo solution. 2 g of sodium dithionite was added to the indigo solution and stirred thoroughly to reduce. Then, the pH of the dyeing solution was adjusted to 7.5 with a lye (sodium hydroxide), and the solution was sealed and reduced for 15 min to obtain a 2 g / L indigo dyeing solution;

[0122] (2) Dyeing of cotton fabric: 50 mL of the dyeing solution from (1) above was used to soak the fabric according to a bath ratio (mass of dyeing solution: mass of fabric) of 10:1. The fabric was dyed at 25°C for 10 min, then taken out, oxidized by air drying for 5 min, washed, and dried.

[0123] (3) Soaping process: the dyed cotton fabric from (2) above was subjected to a soaping process with a bath ratio of 10:1 at a soaping temperature of 25°C for 10 min. After taking out, the fabric was dried to obtain the dyed cotton fabric (12 in FIG. 4).

[0124] Comparative Example 7

[0125] (1) Preparation of N-acetylated indigo dyeing solution: 2 g of N-acetylated indigo powder was dissolved in 1 L of pure water to obtain an N-acetylated indigo solution. 2 g of sodium dithionite was added to the N-acetylated indigo and stirred thoroughly to reduce. Then, the pH of the dyeing solution was adjusted to 6 with an acid solution (citric acid), and the solution was sealed and reduced for 15 min to obtain a 2 g / L N-acetylated indigo dyeing solution;

[0126] (2) Dyeing of textile: 50 mL of the N-acetylated indigo dyeing solution from (1) above was used to soak the fabric according to a bath ratio (mass of N-acetylated indigo dyeing solution: mass of fabric) of 10:1. The fabric was dyed at 25°C for 10 min, then taken out, oxidized by air drying for 5 min, washed, and dried.

[0127] (3) Soaping process: the dyed cotton fabric from (2) above was subjected to a soaping process with a bath ratio of 10:1 at a soaping temperature of 25°C for 10 min. After taking out, the fabric was dried to obtain the dyed cotton fabric (13 in FIG. 4).

[0128] The difference between Example 3 and this example is that the pH is adjusted with an acid solution.

[0129] Comparative Example 8

[0130] The present example provides a method for reducing dyeing using N-acetylated indigo, which comprises the following steps:

[0131] (1) Preparation of N-acetyl kojic blue dyeing solution: 2 g of N-acetyl kojic blue powder is dissolved in 1 L of pure water to obtain an N-acetyl kojic blue solution, 30 g of sodium hydrosulfite is added to the N-acetyl kojic blue solution and stirred to reduce, then an alkali solution (sodium hydroxide) is used to adjust the pH of the dyeing solution to 7.5, and the solution is sealed and reduced for 15 min to obtain a 2 g / L N-acetyl kojic blue dyeing solution;

[0132] (2) Dyeing of textiles: 50 mL of the N-acetyl kojic blue dyeing solution obtained in (1) above is used to soak cotton cloth at a bath ratio (mass of dyeing solution: mass of dyed cloth) of 10:1, and the cloth is dyed at 25°C for 10 min, then taken out, oxidized for 5 min, washed, and dried;

[0133] (3) Soaping process: the dyed cotton cloth obtained in (2) above is subjected to soaping treatment at a soaping bath ratio of 10:1 and a soaping temperature of 25°C for 10 min, then taken out and dried to obtain dyed cotton cloth (14 in FIG. 4).

[0134] The difference from Example 3 is that the mass of sodium hydrosulfite is different.

[0135] Test Example 1

[0136] The dyed cloth samples obtained in Examples 2-6 and Comparative Examples 1-8 above are subjected to multiple dyeing, and the color depth (K / S) and color fastness of the cloth are measured, wherein the color fastness is detected according to GB / T3920-2008 “Textile Color Fastness Test: Color Fastness to Rubbing” and GB / T3921-2008 “Textile Color Fastness Test: Color Fastness to Soaping”, and at least 3 cloth samples are taken for detection in each group, and the average result is obtained. The specific results are shown in Table 2 below, and the dyed cloth samples are shown in FIG. 4.

[0137] Table 2

[0138] From Table 2, it can be seen that:

[0139] Example 2-7 are N-acetyl indigo dyeing fabric quality testing under different conditions, the weak alkaline pH (7.0-8.0) dyeing conditions in the scope of the application, the average color depth K / S is greater than 11.5 to 15.1, and the color depth K / S reaches 15.1 under the optimal condition of pH 7.5. Compared with the average color depth K / S of the optimal indigo dyeing condition (Comparative Example 1) = 10.4, the traditional indigo dyeing condition (Comparative Example 2) average color depth K / S = 3.6, the acid dyeing condition (Comparative Example 7) average color depth K / S = 9.9, and the high insurance powder dyeing condition (Comparative Example 8) average color depth K / S = 10.1, the fabric dyed using the weak alkaline pH reduction dyeing method of the application has higher color depth. Moreover, the color fastness of the optimal condition (Example 3) is better, which is improved compared with Comparative Examples 1-2 and Comparative Examples 7-8, which also shows that the traditional strong alkali reduction dyeing method of indigo or indigo is not suitable for N-acetyl indigo.

[0140] Comparative Example 3 and Comparative Example 4 are indigo optimal condition dyeing and N-acetyl indigo dyeing optimal pH condition method of the application, respectively. Comparative Example 5 and Comparative Example 6 are traditional indigo dyeing and N-acetyl indigo dyeing optimal pH condition method of the application, respectively. It can be seen that the optimal pH for indigo dyeing is 10.0 (Comparative Example 3), and the average color depth K / S of the dyed fabric is 13.6. When dyed at neutral pH (Comparative Example 4), the average color depth K / S is 8.8, which is greatly reduced, while the color fastness is comparable, both being dry rubbing fastness 4, wet rubbing fastness 3-4, and soaping fastness 3-4. While indigo requires more alkali (pH > 12) and a large amount of insurance powder for reduction (Comparative Example 5), the average color depth K / S is 14.0, the dry rubbing fastness is 4, the wet rubbing fastness is 4, and the soaping fastness is 4. When using N-acetyl indigo dyeing under the optimal condition of low insurance powder dosage and low alkali dosage (Comparative Example 6), the color yield on indigo dyed cotton fabric is low, the average color depth K / S is 8.3, and the color fastness is reduced, the dry rubbing fastness is 3-4, the wet rubbing fastness is 3, and the soaping fastness is 3. This also shows that the weak alkali pH reduction dyeing method of the application is not suitable for indigo or indigo.

[0141] Test Example Two

[0142] Take approximately 4cm x 4cm pieces of the dyed fabrics from Examples 2, 3, and 5, and place them in 10mL centrifuge tubes. Add 5mL of DMSO to each tube to soak the fabric pieces and dissolve the pigment. The resulting N-acetylasin blue and indigo blue DMSO solutions were analyzed by liquid chromatography (Figure 5-A, Figure 5-B): Column: Shim-pack GIS 5μm C18 4.6×250mm (HSS), wavelength: 600nm, flow rate: 1.0mL / min, sample solution: DMSO, injection volume: 10μL, column temperature: 35℃, run time: 18min. The peak time was approximately 9.9min for N-acetylasin blue and approximately 8.8min for indigo blue. The resulting indigo blue DMSO solution was analyzed by liquid chromatography (Figure 5-C): Column: The column was set to 4.6 mm id × 250 mm L, with a wavelength of 600 nm, a flow rate of 1.0 ml / min, a sample solution of DMSO, an injection volume of 10 μL, a column temperature of 35 °C, and a run time of 22 min. The elution time of indigo was 14.3 min.

[0143] The DMSO solutions of N-acetylass blue, blue, and indigo-dyed fabrics were subjected to full-wavelength spectral scanning, and the results are shown in Figure 5-D. The maximum absorption wavelength of the DMSO solution for N-acetylass blue dyed fabric was 582 nm, the maximum absorption wavelength of the DMSO solution for blue dyed fabric was 601 nm, and the maximum absorption wavelength of the DMSO solution for indigo-dyed fabric was 609 nm. These values ​​are consistent with the maximum absorption wavelengths of the DMSO solutions prepared with N-acetylass blue (584±2 nm), blue (600±2 nm), and indigo (610±2 nm), respectively (Figure 5).

[0144] In summary, this application is the first to propose the application of N-acetylgamyl in fabric dyeing, and presents a weakly alkaline pH reduction dyeing method suitable for N-acetylgamyl. Compared with dyeing methods for indigo and chrysoberyl (Comparative Examples 3 and 5), this method (Example 3) is gentler and more environmentally friendly. The K / S value and color fastness of fabrics dyed with N-acetylgamyl are comparable to or even improved compared to traditional dyeing methods for indigo and chrysoberyl, but the pH and amount of sodium hydrosulfite used are reduced by more than half. This effectively solves the problems of difficult dyeing, poor color fastness, fabric damage, and difficult wastewater degradation and treatment in the indigo dyeing and finishing industry.

[0145] The dyeing method of the present application is a dyeing method specially applicable to N-acetylsky blue, which reduces pollution and saves cost from both material selection and dyeing process, highlights the green environmental protection concept, and meanwhile, as indicated in the identification of the dye in Example 1, the quality of the cloth piece dyed by using the method of the present application meets the national standard and is safe. Further, the present application also provides a method for identifying and distinguishing N-acetylsky blue, sky blue and indigo, so as to prevent the chemically synthesized commercial indigo from imitating N-acetylsky blue with higher natural degree.

[0146] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A weak base pH reduction staining method using N-acetylglucosamine blue, characterized in that, Includes the following steps: S1. Weigh out N-acetylascan blue and dissolve it in water to form an N-acetylascan blue solution. Add the reducing agent to the N-acetylascan blue solution and stir to reduce it, thereby obtaining a staining solution. Adjust the pH of the staining solution to 7.0-8.0 and let it stand to reduce, thereby obtaining an N-acetylascan blue staining solution. S2. Immerse the textile in the N-acetylass blue dyeing solution obtained in step S1, oxidize it by sun exposure, wash it with water, and dry it. S3. The textiles that have undergone step S2 are soaped and dried to obtain dyed textiles.

2. The weak base pH reduction staining method as described in claim 1, characterized in that, In step S1, the mass ratio of the reducing agent to N-acetylglucosamine is (0.5-3):

1.

3. The weak base pH reduction staining method as described in claim 1, characterized in that, The mass ratio of the reducing agent to N-acetylglucosamine is (1-2):

1.

4. The weak base pH reduction staining method as described in claim 1, characterized in that, The reducing agent includes one of sodium hydrosulfite, sodium sulfide, and sodium formaldehyde sulfoxylate. Preferably, the reducing agent is sodium hydrosulfite.

5. The weak base pH reduction staining method as described in claim 1, characterized in that, In step S1, the pH of the staining solution is adjusted to 7.0-8.0 using an alkaline solution or an acidic solution, preferably pH 7.5; The alkaline solution includes one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, and sodium bicarbonate; preferably, the alkaline solution is sodium hydroxide. The acid solution includes one of sulfuric acid, hydrochloric acid, citric acid, acetic acid, and carbonic acid; preferably, the acid solution is citric acid.

6. The reduction staining method as described in claim 1, characterized in that, In step S1, the time for restoring is 5 to 60 minutes, preferably 10 to 30 minutes.

7. The reduction staining method as described in claim 1, characterized in that, In step S2, the dyeing temperature is 20-60℃, and the dyeing time is 5-20 minutes; the drying and oxidation time is 3-10 minutes.

8. The reduction staining method as described in claim 1, characterized in that, In step S3, the soap bath ratio for the soap washing treatment is 10:1, the soap washing temperature is 20-60℃, and the soap washing time is 5-20 minutes.

9. The reduction staining method as described in claim 1, characterized in that, The textiles include at least one of plant fibers, protein fibers, regenerated fibers, and chemical fibers; Preferably, the plant fiber includes cotton or linen, the protein fiber includes silk or wool, the regenerated fiber includes modal or lyocell, and the chemical fiber includes one of polyester, nylon, and acrylic.

10. The application of N-acetylglucosamine as a dye in fabric dyeing and reduction, characterized in that, The molecular formula of the N-acetylglucosamine is C 12 H 10 N4O5, the structural formula is shown in formula (I);

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