Weak alkaline pH reduction dyeing method using n-acetylcyanide and application thereof

Abstract

The application relates to the dyeing and finishing technical field, in particular to a weak-alkali pH reduction dyeing method using N-acetyl indigo and application thereof, and discloses that N-acetyl indigo is a new type of reduction dye, meets the safety identification requirements of textile dyes, and can be applied to textile dyeing. The application discloses a weak-alkali pH reduction dyeing method using N-acetyl indigo, the dyed textile has a significantly improved color depth, a more brilliant color shade, good color fastness, meets the national standard of textile dyeing, and reduces the content of a reducing agent and environmental pollution.

Description

TECHNICAL FIELD

[0001] The application relates to the dyeing and finishing technical field, in particular to a weak-alkali pH reduction dyeing method using N-acetyl indigoidine and application thereof. BACKGROUND

[0002] Blue is one of the common colors in daily life. Indigo was extracted from plants at an early time and used in the fields of textiles and porcelain. The blue pigment extracted from plants belongs to organic pigments 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 pigments, so in the 19th century, people prepared synthetic indigo through chemical synthesis, which gradually replaced natural blue pigments 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 reducing dye, indigo needs to be reduced into a soluble leuco sodium salt under strong alkaline conditions, and then can be dissolved to dye fabrics. The general dyeing process of indigo in the industry is the caustic soda and sodium hydrosulfite method, which needs to use 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 the increasing emphasis on environmental and energy issues, people tend to pursue sustainable and environmentally friendly methods to prepare dyes, and this synthetic indigo also needs to be replaced by some other natural blue pigments.

[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 a relatively pure product can be obtained through a simple post-processing method. For example, when microorganisms are fermented, L-glutamine is used as a substrate, and two molecules of glutamine are catalyzed by indigo synthase to generate the blue pigment Indigoidine (indigoidine). However, indigoidine still uses a strong alkali reduction 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 indigoidine, and the required pH is about 11. The strong alkaline conditions required for indigoidine dyeing solution still have a certain destructive effect on the environment and textiles.

[0004] In the early stage, the present applicant disclosed that indigoidine synthase and 4'-phosphopantetheinyl transferase were expressed in Escherichia coli, Corynebacterium glutamicum, Saccharomyces cerevisiae and Streptomyces, and that N-acetyl indigoidine was biosynthesized from glutamine and N-acetyl glutamine. However, there is no related report on a weak-alkali pH reduction dyeing method using N-acetyl indigoidine. SUMMARY

[0005] The present application aims to overcome the deficiencies of the prior art and provide a weak alkaline pH reduction dyeing method using N-acetyl indigo and its application. The present application proposes that N-acetyl indigo is a new type of fabric reduction dye. The present application uses a weak alkaline pH reduction dyeing method to dye fabric. 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.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0007] The present application provides a weak alkaline pH reduction dyeing method using N-acetyl indigo, comprising the following steps:

[0008] S1, weigh N-acetyl indigo and dissolve it in water to form an N-acetyl indigo solution, add a reducing agent to the N-acetyl indigo 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 indigo dyeing liquid;

[0009] S2, immerse the textile in the N-acetyl indigo dyeing liquid obtained in step S1 for dyeing, dry and oxidize, wash, and dry;

[0010] S3, perform soaping treatment on the textile after step S2, and dry to obtain a dyed textile.

[0011] The present application determines that N-acetyl indigo is a reduction dye with a product naturalness of 97% and green safety through qualitative detection of dyes, safety detection of dyes, USDA product naturalness detection, etc. mentioned in ISO 16373-1:2015 (General principles of testing coloured textiles for dyestuff identification).

[0012] N-acetyl indigo belongs to the derivative of indigo, and is the aminoacylation product of L-glutamine during the synthesis of indigo in microorganisms. The presence of acetyl group can further reduce the required amount of alkali (the pH of the dyeing liquid is closer to neutral), reduce the polarity of N-acetyl indigo, and thus the dyed fabric is not easily washed off, which helps to increase the color fastness. N-acetyl indigo, as a reduction dye, is quite different from traditional reduction 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 state relatively better, which is conducive to reducing the amount of reducing agent during reduction. In addition, due to the presence of aminoacyl group, the polarity is reduced, and after dyeing on the fabric, it is more difficult to be washed off by water, thereby increasing the color fastness.

[0013] The application applies the biosynthetic N-acetyl indigo blue, a new natural blue pigment, to fabric dye, and establishes a weak alkali pH reduction dyeing method for N-acetyl indigo blue for textiles, so as to reduce environmental pollution and production cost; the main quality indexes of the N-acetyl indigo blue dyed textiles, such as color, depth and color fastness, reach or exceed the quality level of the current indigo or indigo dyed fabrics.

[0014] The weak alkali pH reduction dyeing method of the application is adopted, 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; DMSO is used to dissolve the pigment on the textiles, and liquid phase detection proves that the pigment of the dyed textiles is N-acetyl indigo blue.

[0015] As a preferred embodiment of the weak alkali pH reduction dyeing method using N-acetyl indigo blue described in the application, in the step S1, the mass ratio of the reducing agent to N-acetyl indigo blue is (0.5-3):1.

[0016] As a preferred embodiment of the weak alkali pH reduction dyeing method using N-acetyl indigo blue described in the application, the mass ratio of the reducing agent to N-acetyl indigo blue is (1-2):1.

[0017] The reducing agent and N-acetyl indigo blue in the above mass ratio can ensure that most of the N-acetyl indigo blue is reduced to leuco bodies, and the dyeing effect is obvious; when the mass of N-acetyl indigo blue is too much, the dyeing deepening is not obvious; when the reducing agent is too much, the N-acetyl indigo blue is excessively reduced and is not easy to oxidize back, and the pollutants in the dyeing waste liquid are increased.

[0018] As a preferred embodiment of the weak alkali pH reduction dyeing method using N-acetyl indigo blue described in the application, the reducing agent includes one of sodium hydrosulfite, sodium sulfide and sodium dithionite;

[0019] Preferably, the reducing agent is sodium hydrosulfite, i.e. sodium dithionite.

[0020] The application uses N-acetyl indigo blue for weak alkali pH reduction dyeing, which can reduce the amount of reducing agents such as sodium hydrosulfite, and at the same time, increases the dyeing color fastness, which is helpful for textile dyeing.

[0021] As a preferred embodiment of the weak alkali pH reduction dyeing method using N-acetyl indigo blue described in the application, in the step S1, the pH of the dyeing liquid is adjusted to 7.0-8.0 by using alkali or acid, and the pH is preferably 7.5;

[0022] The alkali includes one of sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate and sodium bicarbonate; preferably, the alkali is sodium hydroxide.

[0023] The acid liquor includes one of sulfuric acid, hydrochloric acid, citric acid, acetic acid, and carbonic acid; preferably, the acid liquor is citric acid.

[0024] As a preferred embodiment of the weak alkaline pH reduction dyeing method using N-acetyl observed blue described in the present application, the reduction placement time in step S1 is 5-60 min, preferably 10-30 min.

[0025] When the reduction placement time is too short, the reduction is insufficient, and when the reduction placement time is too long, the hydrosulfite is ineffective, both of which reduce the dyeing rate of N-acetyl observed blue.

[0026] As a preferred embodiment of the weak alkaline pH reduction dyeing method using N-acetyl observed blue described in the present application, the dyeing temperature in step S2 is 20-60℃, and the dyeing time is 5-20 min; the air oxidation time is 3-10 min.

[0027] When the dyeing temperature exceeds 60℃, N-acetyl observed blue is damaged, and when the temperature is lower than 20℃, N-acetyl observed blue dyeing liquor is not easy to penetrate into the inside of the fabric.

[0028] When the air oxidation time is less than 3 min, the re-washing reduces the color yield, and the fabric color depth is reduced; when the air oxidation time is more than 10 min, the re-washing causes the fabric surface to have color spots that are not easy to wash off, resulting in uneven dyeing.

[0029] As a preferred embodiment of the weak alkaline pH reduction dyeing method using N-acetyl observed blue described in the present application, in step S2, the mass ratio of N-acetyl observed blue dyeing liquor to textile is (10-100):1.

[0030] As a preferred embodiment of the weak alkaline pH reduction dyeing method using N-acetyl observed blue described in the present application, in step S3, the soaping treatment has a soaping bath ratio of 10:1, the soaping temperature is 20-60℃, and the soaping time is 5-20 min.

[0031] The soaping bath ratio is a term used in textile dyeing and finishing, which refers to the mass ratio of textile to N-acetyl observed blue dyeing liquor in the immersion dyeing method, and in actual application, the density of the dyeing liquor is often treated as 1.

[0032] In the technical solution of the present application, the soaping treatment can wash off the floating color on the surface of the textile, which is beneficial to increase the color fastness of dyeing.

[0033] The present application provides a weak alkaline pH reduction dyeing method with low hydrosulfite amount (0.5-3 times the mass of N-acetyl observed blue), low alkali amount (pH 7.0-8.0), and more mildness.

[0034] As a preferred embodiment of the weak alkaline pH vat dyeing method using N-acetyl indigo described in the present application, the textile product comprises at least one of plant fiber, protein fiber, regenerated fiber and chemical fiber;

[0035] Preferably, the plant fiber comprises cotton or hemp, the protein fiber comprises silk or wool, the regenerated fiber comprises modal or lyocell, and the chemical fiber comprises one of polyester, nylon and acrylic.

[0036] The present application also provides an application of N-acetyl indigo in fabric dyeing reduction as a dye, the molecular formula of the N-acetyl indigo is C 12 H 10 N4O5, and the structural formula is shown as formula (I);

[0037]

[0038] N-acetyl indigo is a new type of fabric vat dye, the natural degree of N-acetyl indigo product is 97%, which is identified as a vat dye and proved to be green and safe through dye safety detection.

[0039] The present application also includes quality identification on the dyed textile product. Color difference meter is used to measure and calculate K / S value to characterize the light and shade of the dyed textile product, and GB / T 3920-2008 “Textile color fastness test resistance to rubbing color fastness” and GB / T 3921-2008 “Textile color fastness test resistance to soaping color fastness” are referred to test the resistance to rubbing color fastness and resistance to soaping color fastness of the dyed textile product. Product quality detection shows that the main quality indexes such as color, depth and fastness of the N-acetyl indigo dyed textile product obtained under the preferred conditions of the weak alkaline pH vat dyeing method reach or exceed the quality level of the current indigo or indigo dyed textile product; and the main quality indexes such as color, depth and fastness of the indigo or indigo dyed textile product obtained under the preferred conditions of the weak alkaline pH vat dyeing method cannot reach the quality standard of the dyed textile product.

[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 the N-acetyl indigo dyed textile solution is about 584±2nm, the maximum absorption wavelength of the indigo dyed textile solution is about 600±2nm, and the maximum absorption wavelength of the indigo dyed textile solution is about 610±2nm, which can be used as a method for identifying the three different dye 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 textile has significantly improved color depth, brighter color, good color fastness, meets the national standard of textile dyeing, reduces the content of alkali, reduces environmental pollution, and meets different market demands. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 Molecular structure diagrams of indigo, indigo blue and N-acetyl indigo blue Figure 1 -A is indigo; Figure 1 -B is indigo blue; Figure 1 -C is N-acetyl indigo blue;

[0044] Figure 2 N-acetyl indigo blue dye type identification experiment diagram

[0045] Figure 3 N-acetyl indigo blue natural degree certification

[0046] Figure 4 Dyeing cotton cloth display diagrams of examples 2-6 and comparative examples 1-8 (in the diagrams, 1 is an undyed cloth piece, 2-8 are dyeing diagrams of N-acetyl indigo examples 2-6 and comparative examples 1 and 2, 9 and 10 are dyeing diagrams of indigo comparative examples 3 and 4, 11 and 12 are dyeing diagrams of indigo comparative examples 5 and 6, and 13 and 14 are dyeing diagrams of N-acetyl indigo comparative examples 7 and 8)

[0047] Figure 5 Liquid chromatogram and ultraviolet full wavelength scan diagram of three pigments dissolved on the cloth pieceFigure 5 -A is the liquid phase diagram of N-acetyl blue; Figure 5 -B is the liquid phase diagram for observing blue; Figure 5 -C is the liquid phase diagram of indigo; Figure 5 -D represents the full-wavelength spectral scan of the three pigments. Detailed Implementation

[0048] To better illustrate the purpose, technical solution, and advantages of this application, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

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

[0050] The N-acetylglucosamine and glucosamine used in the following examples were obtained by our company (Nanjing Hegu Life Biotechnology Co., Ltd.) through self-developed fermentation.

[0051] The safety report for the N-acetylglucosamine in this application was issued by the Shaoxing Municipal Institute of Quality and Technical Supervision and Inspection. The dye type was determined by the inventor through experiments according to the method provided in the international standard ISO 16373-1:2015, and the product naturalness certification was obtained from the USDA Biopreferred Program.

[0052] From Examples 2 to 7, N-acetylglucosamine was used for dyeing tests under different conditions; Comparative Examples 1 and 2 were for glucosamine dyeing tests; Comparative Examples 3 and 4 were for indigo dyeing tests. In Example 8, the dyed fabrics from Examples 2-7 and Comparative Examples 1-4 were subjected to quality testing. The K / S value was used to characterize the depth of color of the dyed cotton fabric. The color fastness to rubbing and color fastness to washing of the cotton fabric were tested according to GB / T 3920—2008 "Textiles - Tests for Color Fastness to Rubbing" and GB / T 3921—2008 "Textiles - Tests for Color Fastness to Washing". In Example 9, the dyed fabrics from Examples 2, Comparative Examples 1 and 3 were immersed in DMSO to dissolve the pigments, and the solutions were subjected to a full-wavelength spectral scan to compare the maximum absorption wavelengths of the three blue pigments.

[0053] The molecular structure diagrams of indigo, safflower, and N-acetylasafflower mentioned in the following examples and comparative examples are as follows: Figure 1 As shown ( Figure 1 -A represents indigo; Figure 1 -B is for viewing blue; Figure 1 -C represents N-acetylglucosamine (C is N-acetylglucosamine blue).

[0054] Example 1: Identification of N-acetylglucosamine dye type, safety, and naturalness.

[0055] The dye type of N-acetyl indigo 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 indigo pure product was sent to Shaoxing Quality and Technical Supervision Testing Institute for dye safety detection, mainly detecting whether N-acetyl indigo contains harmful aromatic amines, heavy metal content, harmful solvents, etc. In addition, the N-acetyl indigo pure product was also sent to the United States Department of Agriculture (USDA) for product naturalness detection.

[0056] Specifically:

[0057] Since N-acetyl indigo 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 indigo, and the specific experimental steps are shown in (A-F), and the experimental results are shown in Figure 2 ( Figure 2 -A to Figure 2 -F).

[0058] A. 0.2 g of N-acetyl indigo sample was treated 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 indigo was not dissolved in 1% ammonia water, so indigo is not an acid dye;

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

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

[0061] D. Since N-acetyl indigo will change when pH>12, the N-acetyl indigo 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 indigo is a reducing dye.

[0062] E. A small amount of N-acetyl indigo sample was heated with concentrated sulfuric acid for a few seconds, and then 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 an aniline black dye.

[0063] F. A small amount of N-acetyl indigo sample was heated with concentrated sulfuric acid for a few seconds, and then 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 an aniline black dye.

[0064] Based on the above, the identification result is that N-acetyl indigo is a new substance, which is a vat dye. The most commonly used blue vat dye is synthetic indigo, which is synthesized by chemical methods, 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]

[0067]

[0068] 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% (BioPreferred Program). Figure 3 Therefore, N-acetyl indigo has the characteristics of being more natural, environmentally friendly, and green and safe.

[0069] Example 2

[0070] The present embodiment provides a weak alkaline pH vat dyeing method using N-acetyl indigo, comprising the following steps:

[0071] (1) Preparation of N-acetyl indigo dyeing solution: 1 g of N-acetyl indigo powder was dissolved in 1 L of pure water to obtain an N-acetyl indigo solution, and 0.5 g of sodium dithionite was added to the N-acetyl indigo and stirred to reduce, and then the pH of the dyeing solution was adjusted to 7.0 with a lye (sodium hydroxide), and the solution was sealed and reduced for 5 min, to obtain a 1 g / L N-acetyl indigo dyeing solution;

[0072] (2) Dyeing of textile: 50 mL of N-acetyloxyblue dyeing solution from the above (1) is taken, cotton cloth is soaked according to bath ratio (mass of N-acetyloxyblue dyeing solution: mass of dyed cotton cloth) 10:1, taken out after dyeing at 20°C for 5 min, air oxidation for 3 min, then washed with water, and dried;

[0073] (3) Soaping process: the cotton cloth dyed in the above (2) is subjected to soaping treatment, soaping bath ratio 10:1, soaping temperature 20°C, soaping time 5 min, and dried after taking out, to obtain dyed cotton cloth Figure 4 Example 2, Figure 4 Example 1 is a control undyed cloth piece).

[0074] Example 3

[0075] The embodiment provides a weak alkaline pH reduction dyeing method using N-acetyloxyblue, which comprises the following steps:

[0076] (1) Preparation of N-acetyloxyblue dyeing solution: 2 g of N-acetyloxyblue powder is dissolved in 1 L of pure water to obtain an N-acetyloxyblue solution, 2 g of sodium hydrosulfite (sodium dithionite) is added to the N-acetyloxyblue 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 2 g / L of N-acetyloxyblue dyeing solution;

[0077] (2) Dyeing of textile: 50 mL of N-acetyloxyblue dyeing solution from the above (1) is taken, cotton cloth is soaked according to bath ratio (mass of N-acetyloxyblue dyeing solution: mass of dyed cotton cloth) 10:1, taken out after dyeing at 25°C for 10 min, air oxidation for 5 min, then washed with water, and dried;

[0078] (3) Soaping process: the cotton cloth dyed in the above (2) is subjected to soaping treatment, soaping bath ratio 10:1, soaping temperature 25°C, soaping time 10 min, and dried after taking out, to obtain dyed cotton cloth Figure 4 Example 3).

[0079] Example 4

[0080] The embodiment provides a weak alkaline pH reduction dyeing method using N-acetyloxyblue, which comprises the following steps:

[0081] (1) Preparation of N-acetyloxyblue dyeing solution: 2 g of N-acetyloxyblue powder is dissolved in 1 L of pure water to obtain an N-acetyloxyblue solution, 2 g of sodium hydrosulfite (sodium dithionite) is added to the N-acetyloxyblue 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 2 g / L of N-acetyloxyblue dyeing solution;

[0082] (2) Dyeing of textile: Take 250 mL of N-acetyl sky blue dyeing solution from the above (1), soak the cotton cloth according to the bath ratio (mass of N-acetyl sky blue 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;

[0083] (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 is obtained after being taken out and dried. Figure 4

[0084] Example 5

[0085] The embodiment provides a weak alkaline pH reduction dyeing method using N-acetyl sky blue, which comprises the following steps:

[0086] (1) Preparation of N-acetyl sky blue dyeing solution: 1 g of N-acetyl sky blue powder is dissolved in 1 L of pure water to obtain an N-acetyl sky blue solution, 2 g of sodium hydrosulfite (sodium dithionite) is added to the N-acetyl sky blue 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 30 min to obtain a 2 g / L N-acetyl sky blue dyeing solution;

[0087] (2) Dyeing of textile: Take 50 mL of N-acetyl sky blue dyeing solution from the above (1), soak the cotton cloth according to the bath ratio (mass of N-acetyl sky blue 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;

[0088] (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 is obtained after being taken out and dried. Figure 4

[0089] Example 6

[0090] The embodiment provides a weak alkaline pH reduction dyeing method using N-acetyl sky blue, which comprises the following steps:

[0091] (1) Preparation of N-acetyl sky blue dyeing solution: 2 g of N-acetyl sky blue powder is dissolved in 1 L of pure water to obtain an N-acetyl sky blue solution, 2 g of sodium hydrosulfite (sodium dithionite) is added to the N-acetyl sky blue 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 10 min to obtain a 2 g / L N-acetyl sky blue dyeing solution;

[0092] ​​(2) Dyeing of textile: 50 mL of N-acetyl sky blue dyeing solution from the above (1) is taken, cotton cloth is soaked according to bath ratio (mass of N-acetyl sky blue dyeing solution: mass of dyed cotton cloth) 10:1, taken out after dyeing at 60°C for 10 min, air oxidation for 5 min, then washed with water, and dried;

[0093] (3) Soaping process: the cotton cloth dyed in the above (2) is subjected to soaping treatment, soaping bath ratio 10:1, soaping temperature 60°C, soaping time 10 min, and dried after taking out, to obtain dyed cotton cloth Figure 4

[0094] Comparative Example 1

[0095] This comparative example uses the optimal condition of strong alkali reduction dyeing method of sky blue to reduce dye N-acetyl sky blue.

[0096] This comparative example provides a strong alkali reduction dyeing method using N-acetyl sky blue, comprising the following steps:

[0097] (1) Preparation of N-acetyl sky blue dyeing solution: 2 g of N-acetyl sky blue powder is dissolved in 1 L of pure water to obtain N-acetyl sky blue solution, 4 g of sodium hydrosulfite (hyposulfite) is added to the N-acetyl sky blue and stirred to reduce, then the pH of the dyeing solution is adjusted to 10.0 with lye (sodium hydroxide), and the reduction is sealed and placed for 15 min, to obtain 2 g / L of N-acetyl sky blue dyeing solution;

[0098] (2) Dyeing of textile: 50 mL of N-acetyl sky blue dyeing solution from the above (1) is taken, cotton cloth is soaked according to bath ratio (mass of N-acetyl sky blue dyeing solution: mass of dyed cotton cloth) 10:1, taken out after dyeing at 25°C for 10 min, air oxidation for 5 min, then washed with water, and dried;

[0099] (3) Soaping process: the cotton cloth dyed in the above (2) is subjected to soaping treatment, soaping bath ratio 10:1, soaping temperature 25°C, soaping time 10 min, and dried after taking out, to obtain dyed cotton cloth Figure 4

[0100] Comparative Example 2

[0101] This comparative example uses the general strong alkali reduction method of indigo dyeing to reduce dye N-acetyl sky blue.

[0102] This comparative example provides a strong alkali reduction dyeing method using N-acetyl sky blue, comprising the following steps:

[0103] ​​(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 hydrosulfite (hydrosulfurous acid sodium) 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;

[0104] (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;

[0105] (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 (Example 8). Figure 4

[0106] Comparative Example 3

[0107] In this comparative example, indigo was used as a comparison. Indigo (existing) was also developed by our company (Nanjing Hegot Life Biotechnology Co., Ltd.) through fermentation and can be purchased from the company's official website. The best conditions for indigo dyeing at present are 2 times of sodium hydrosulfite reduction, dyeing at pH 10.0, which is a strong alkali reduction dyeing method.

[0108] (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 hydrosulfite (hydrosulfurous acid sodium) was added to the indigo and stirred to reduce, then the pH of the dyeing solution was adjusted to 10.0 with lye (sodium hydroxide), and the reduction was sealed and placed for 15 min to obtain 2 g / L of indigo dyeing solution;

[0109] (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;

[0110] (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 (Example 9). Figure 4

[0111] Comparative Example 4

[0112] ​​In this embodiment, blue violet was used as a comparison. Blue violet (existing) was also obtained by our company (Nanjing Hegu Life Biotechnology Co., Ltd.) through self-developed fermentation and can be purchased from the company's official website. The staining method was carried out according to the optimized conditions of the above-mentioned N-acetylated blue violet weak base pH reduction staining method in Example 3.

[0113] (1) Preparation of indigo staining solution: Weigh 2g of indigo powder and dissolve it in 1L of pure water to obtain indigo solution. Weigh 2g of sodium dithionite and add it to the indigo solution. Stir and reduce it thoroughly. Then adjust the pH of the staining solution to 7.5 with alkaline solution (sodium hydroxide). Seal and let it reduce for 15min to obtain 2g / L indigo staining solution.

[0114] (2) Dyeing of cotton fabric: Take 50 mL of indigo dyeing solution from (1) above, soak the fabric at a bath ratio (mass of indigo dyeing solution: mass of dyed fabric) 10:1, dye at 25℃ for 10 min, take it out, dry it for 5 min to oxidize, then wash it with water and dry it.

[0115] (3) Soap washing process: The dyed cotton fabric from (2) above is subjected to soap washing treatment with a soap washing bath ratio of 10:1, a soap washing temperature of 25℃, and a soap washing time of 10 minutes. After removal and drying, the dyed cotton fabric can be obtained. Figure 4 10).

[0116] Comparative Example 5

[0117] Commercial indigo was used as a control in this comparative example. The commercial indigo was purchased from Ron Reagents, and the staining method was the general strong alkali reduction staining method for indigo, namely, reduction staining with sodium hydrosulfite at 15 times the weight of indigo and caustic soda at 5 times the weight of indigo.

[0118] (1) Preparation of indigo dyeing solution: Weigh 2g of indigo powder and dissolve it in 1L of pure water to obtain indigo solution. Weigh 30g of sodium dithionite and add it to the indigo solution. Stir and reduce it thoroughly. Then add 10g of sodium hydroxide. At this time, the pH is about 13.2. Seal and let it reduce for 20min to obtain 2g / L indigo dyeing solution.

[0119] (2) Dyeing of cotton fabric: Take 50 mL of dyeing solution from (1) above, soak the cotton fabric at a bath ratio (mass of dyeing solution: mass of dyed fabric) of 10:1, dye at 25℃ for 10 min, take it out, dry it for 5 min to oxidize, then wash it with water and dry it.

[0120] (3) Soap washing process: The dyed cotton fabric from (2) above is subjected to soap washing treatment with a soap washing bath ratio of 10:1, a soap washing temperature of 25℃, and a soap washing time of 10 minutes. After removal and drying, the dyed cotton fabric can be obtained. Figure 4 (11).

[0121] Comparative Example 6

[0122] The comparative example selects commercial indigo as a comparison, and the commercial indigo is purchased from Rongen Reagent. The dyeing method is carried out according to the optimized condition of the N-acetyl indigo weak alkaline pH reduction dyeing method in Example 3.

[0123] (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 (sodium hydrosulfite) was added to the indigo solution and stirred to reduce, then the pH of the dyeing solution was adjusted to 7.5 with a lye (sodium hydroxide), and the dyeing solution was sealed and reduced for 15 min to obtain a 2 g / L indigo dyeing solution;

[0124] (2) Dyeing of cotton fabric: 50 mL of the dyeing solution in (1) above was taken, and the fabric was soaked according to a bath ratio (mass of dyeing solution: mass of dyed fabric) of 10:1, dyed at 25°C for 10 min, taken out, oxidized by air drying for 5 min, washed with water, and dried;

[0125] (3) Soaping process: the dyed cotton fabric in (2) above was subjected to soaping treatment, the soaping bath ratio was 10:1, the soaping temperature was 25°C, the soaping time was 10 min, and the dyed cotton fabric was obtained after being taken out and dried. Figure 4

[0126] Comparative Example 7

[0127] (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, 2 g of sodium dithionite (sodium hydrosulfite) was added to the N-acetyl indigo and stirred to reduce, then the pH of the dyeing solution was adjusted to 6 with an acid solution (citric acid), and the dyeing solution was sealed and reduced for 15 min to obtain a 2 g / L N-acetyl indigo dyeing solution;

[0128] (2) Dyeing of textile: 50 mL of the N-acetyl indigo dyeing solution in (1) above was taken, and the cotton fabric was soaked according to a bath ratio (mass of N-acetyl indigo dyeing solution: mass of dyed cotton fabric) of 10:1, dyed at 25°C for 10 min, taken out, oxidized by air drying for 5 min, washed with water, and dried;

[0129] (3) Soaping process: the dyed cotton fabric in (2) above was subjected to soaping treatment, the soaping bath ratio was 10:1, the soaping temperature was 25°C, the soaping time was 10 min, and the dyed cotton fabric was obtained after being taken out and dried. Figure 4

[0130] The difference from Example 3 is that the pH is adjusted with an acid solution.

[0131] Comparative Example 8

[0132] The present example provides a reduction dyeing method using N-acetyl indigo, comprising the following steps:​​

[0133] (1) Preparation of N-acetyl kojic blue dyeing solution: 2 g of N-acetyl kojic blue powder was dissolved in 1 L of pure water to obtain an N-acetyl kojic blue solution, 30 g of sodium hydrosulfite was added to the N-acetyl kojic blue solution and 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-acetyl kojic blue dyeing solution;

[0134] (2) Dyeing of textiles: 50 mL of the N-acetyl kojic blue dyeing solution obtained in (1) above was used to soak cotton cloth at a bath ratio (mass of dyeing solution: mass of dyed cloth) of 10:1, and the cloth was dyed at 25°C for 10 min, then taken out, oxidized for 5 min, washed, and dried;

[0135] (3) Soaping process: the dyed cotton cloth obtained in (2) above was subjected to soaping treatment at a soaping bath ratio of 10:1 and a soaping temperature of 25°C for 10 min, and then taken out and dried to obtain dyed cotton cloth (14). Figure 5

[0136] The difference from Example 3 is that the mass of sodium hydrosulfite is different.

[0137] Test Example One

[0138] The dyed cloth samples obtained in Examples 2-6 and Comparative Examples 1-8 above were subjected to multiple dyeing, and the color depth (K / S) and color fastness of the cloth were determined. The color fastness was detected according to GB / T 3920-2008 “Textile Color Fastness Test: Color Fastness to Rubbing” and GB / T 3921-2008 “Textile Color Fastness Test: Color Fastness to Soaping”. At least 3 cloth samples were taken for detection in each group, and the average result was obtained. The specific results are shown in Table 2 below, and the dyed cloth samples are shown in Figure 5 .

[0139] Table 2

[0140]

[0141]

[0142] From Table 2, it can be seen that:

[0143] ​Example 2-7 are N-acetyl indigo dyeing fabric quality test under different conditions, the average color depth K / S of weak alkaline pH (7.0-8.0) dyeing conditions in the scope of the application 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 indigo optimal dyeing condition (comparative example 1) = 10.4, traditional indigo dyeing condition (comparative example 2) = 3.6, acid dyeing condition (comparative example 7) = 9.9, and high insurance powder dyeing condition (comparative example 8) = 10.1, the fabric dyed by the weak alkaline pH reduction dyeing method of the application all obtains higher color depth. Moreover, the color fastness of the optimal condition of the application (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 alkaline reduction dyeing method of indigo or indigo is not suitable for N-acetyl indigo.

[0144] 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), 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 equivalent, both are dry rubbing fastness 4, wet rubbing fastness 3-4, and soaping fastness 3-4. While indigo needs more alkali (pH>12), and also needs a large amount of insurance powder for reduction (comparative example 5), at this time 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 low insurance powder dosage and low alkali dosage under the optimal condition of N-acetyl indigo dyeing (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 alkaline pH reduction dyeing method of the application is not suitable for indigo or indigo.

[0145] Test example two

[0146] Take about 4cm x 4cm sized fabric pieces from the dyed fabric of example 2, comparative example 3 and comparative example 5, respectively, and put them into 10mL centrifuge tubes, then add 5mL of DMSO to soak the fabric pieces for dissolving pigments. The obtained DMSO solutions of N-acetyl indigo and indigo are subjected to liquid phase detection Figure 5 -A, Figure 5B): Column: Shim-pack GIS 5 μm C18 4.6x250mm (HSS), wavelength 600 nm, flow rate 1.0 ml / min, sample solution DMSO, injection volume 10 μL, column temperature 35 °C, running time 18 min. The N-acetylsolferine DMSO solution obtained was detected by liquid chromatography (LC) (the peak time of N-acetylsolferine was about 9.9 min, and the peak time of solferine was about 8.8 min) Figure 5 C): Column: Galasil○ R EF-C18M 4.6mm idx250mm L, wavelength 600 nm, flow rate 1.0 ml / min, sample solution DMSO, injection volume 10 μL, column temperature 35 °C, running time 22 min. The peak time of indigo was 14.3 min.

[0147] The DMSO solutions of the N-acetylsolferine, solferine and indigo dyed fabrics obtained were scanned by full wavelength spectrum, and the results are shown in Figure D. The maximum absorption wavelength of the DMSO solution of the N-acetylsolferine dyed fabric was 582 nm, the maximum absorption wavelength of the DMSO solution of the solferine dyed fabric was 601 nm, and the maximum absorption wavelength of the DMSO solution of the indigo dyed fabric was 609 nm, which were consistent with the maximum absorption wavelength values of the DMSO solutions prepared by N-acetylsolferine (584±2 nm), solferine (600±2 nm) and indigo (610±2 nm) dyes, respectively (as shown in Figure E). ​ ​

[0148] In summary, the application first proposes the application of N-acetylsolferine in fabric dyeing, and proposes a weak alkaline pH reduction dyeing method suitable for N-acetylsolferine. The method (Example 3) is more environmentally friendly than the dyeing methods of solferine and indigo (Comparative Example 3 and Comparative Example 5). The K / S value and color fastness of the N-acetylsolferine dyed fabric are comparable to or even better than those of the traditional solferine and indigo dyeing, but the pH and the amount of sodium hydrosulfite used are reduced by more than 1 times, effectively solving the problems of difficult dyeing, poor color fastness, damage to fabric, difficult degradation and treatment of wastewater in the indigo dyeing and finishing industry.

[0149] The dyeing method of the application is a dyeing method specifically suitable for N-acetylsolferine, which reduces pollution and saves cost from the selection of materials and the dyeing process, highlights the concept of green environmental protection, and at the same time, as indicated by the identification of the dye in Example 1, the quality of the fabric dyed by the method of the application meets the national standards, and the safety is guaranteed. Further, the application also provides a method for identifying and distinguishing N-acetylsolferine, solferine and indigo, so as to prevent the chemical synthetic commercial indigo from imitating the N-acetylsolferine with higher natural degree.

[0150] ​​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 scope of protection 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 equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A weak alkaline pH reduction dyeing method using N-acetylcyanide, characterized by, The method comprises the following steps: S1, N-acetyl indigo is weighed and dissolved in water to form an N-acetyl indigo solution, a reducing agent is added to the N-acetyl indigo solution and stirred to reduce, an N-acetyl indigo dyeing solution is obtained, the pH of the dyeing solution is adjusted to 7.0-8.0, and the N-acetyl indigo dyeing solution is placed to reduce, thereby obtaining the N-acetyl indigo dyeing solution; S2, the textile is soaked and dyed in the N-acetyl indigo dyeing solution obtained in step S1, is dried and oxidized, is washed, and is dried; S3, the textile subjected to step S2 is subjected to soaping treatment, and is dried, thereby obtaining the dyed textile; In step S1, the mass ratio of the reducing agent to the N-acetyl indigo is (0.5-3):1; In step S1, the reducing is placed for 5-60 min.

2. The weak alkaline pH vat dyeing method according to claim 1, characterized in that, The mass ratio of the reducing agent to the N-acetyl indigo is (1-2):

1.

3. The weak alkaline pH vat dyeing method according to claim 1, characterized by, The reducing agent comprises one of sodium hydrosulfite, sodium sulfide and sodium dithionite.

4. The weak alkaline pH vat dyeing method according to claim 3, characterized in that, The reducing agent is sodium hydrosulfite.

5. The weak alkaline pH vat dyeing method according to claim 1, characterized by, In step S1, the pH of the dyeing solution is adjusted to 7.0-8.0 by using a lye or an acid solution; The lye comprises one of sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate and sodium bicarbonate; The acid solution comprises one of sulfuric acid, hydrochloric acid, citric acid, acetic acid and carbonic acid.

6. The weak alkaline pH vat dyeing method according to claim 5, characterized by, In step S1, the pH of the dyeing solution is adjusted to 7.5 by using a lye or an acid solution; The lye is sodium hydroxide; The acid solution is citric acid.

7. The vat dyeing method according to claim 1, wherein In step S1, the reducing is placed for 10-30 min.

8. The vat dyeing method according to claim 1, wherein In step S2, the dyeing temperature is 20-60℃, the dyeing is performed for 5-20 min, and the drying and oxidizing is performed for 3-10 min.

9. The vat dyeing method according to claim 1, wherein In step S3, the soaping treatment is performed at a soaping bath ratio of 10:1, the soaping temperature is 20-60℃, and the soaping time is 5-20 min.

10. The vat dyeing method according to claim 1, wherein The textile comprises at least one of plant fibers, protein fibers, regenerated fibers and chemical fibers.

11. The vat dyeing method according to claim 10, characterized in that, The plant fibers comprise cotton or hemp, the protein fibers comprise silk or wool, the regenerated fibers comprise modal or lyocell, and the chemical fibers comprise one of polyester, nylon and acrylic.

12. Use of N-acetylcyanidin as a dye in the reduction dyeing of fabrics, characterized in that, The N-acetyl indigo is applied to textile dyeing by the weak alkaline pH reduction dyeing method according to any one of claims 1-11, and the maximum absorption wavelength of the dyed textile after being dissolved in DMSO is 584±2 nm. The molecular formula of the N-acetyl-obscurine is C 12 H 10 N4O5, and the structural formula is shown as formula (I). Formula (I).

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