Black direct dyes, processes for their preparation and use

Abstract

The present application provides a kind of black direct dye and its preparation method and use.The black direct dye includes the compound shown in the following formula (I): Wherein, R1, R2, R3, R4, R5, R6 each independently is H, -SO3M or -NH2, R1, R2, R3, R4, R5, R6 are not simultaneously H;And, when R1 and R4 are -NH2, R2, R3, R5, R6 are not simultaneously H, when R3 and R5 are -NH2, R1, R2, R4, R6 are not simultaneously H;M is H or alkali metal element.The black direct dye of the present application is bright and brilliant, has good solubility, high color fastness, environmental protection (does not contain aniline), and excellent dyeing performance.In addition, the preparation method of the black direct dye of the present application has less wastewater, is friendly to the environment, and is conducive to realizing clean production.

Description

Technical Field

[0001] This invention relates to a black direct dye, its preparation method, and its uses, belonging to the field of dye synthesis. Background Technology

[0002] Direct dyes are dyes that can be directly dissolved in water or suspended in water with the help of dispersants. They have a wide range of applications, including dyeing textiles such as protein fibers and cellulose fibers, as well as dyeing inks and paper. Market demand is high. Single-color black direct dyes are more stable than multi-color black direct dyes, have simpler product formulations, and are consumed in large quantities.

[0003] There is considerable research on existing direct black dyes on the market. Patent CN105219121A proposes a synthesis process for Direct Fast Black G. This process involves electrodialysis to recover acids and alkalis from the wastewater after the reduction of sodium sulfide dye, thus reducing wastewater volume. However, electrodialysis treatment of saline wastewater is costly, and the recovered wastewater still requires further treatment before it can be discharged safely. Patent CN101580650A proposes a synthesis process for Direct Fast Black 22. This process involves spray drying the dye to obtain the finished product, avoiding wastewater generation. However, the current market reports indicate that Direct Fast Black 22 has a reddish hue and low solubility. Therefore, developing a direct black dye with good solubility, a greenish hue, excellent dyeing performance, and low wastewater production has become an urgent technical problem to be solved. Summary of the Invention

[0004] The problem the invention aims to solve

[0005] In view of the technical problems existing in the prior art, and based on the requirements of environmentally friendly dyes, such as poor dye solubility, reddish color, poor dyeing performance and large amount of production wastewater, this invention provides a black direct dye and its preparation method. This method can effectively improve the dye solubility, improve the dye color and dyeing performance, and at the same time effectively reduce production wastewater during the preparation process, thus achieving green production.

[0006] Solution for solving the problem

[0007] This invention provides a black direct dye comprising a compound with the structural formula shown in formula (Ⅰ):

[0008]

[0009] Among them, R1, R2, R3, R4, R5, and R6 are each independently H, -SO3M, or -NH2, and R1, R2, R3, R4, R5, and R6 are not simultaneously H; furthermore, when R1 and R4 are -NH2, R2, R3, R5, and R6 are not simultaneously H, and when R3 and R5 are -NH2, R1, R2, R4, and R6 are not simultaneously H.

[0010] M is H or an alkali metal element.

[0011] The black direct dye according to the present invention comprises one or more of the compounds shown in formulas (I-1) to (I-3) below:

[0012]

[0013] The black direct dye according to the present invention comprises a combination of two or more compounds represented by formulas (I-1) to (I-3) and (II):

[0014]

[0015]

[0016] Furthermore, the present invention also provides a method for preparing a black direct dye according to the present invention, which includes the following steps:

[0017] The steps to obtain the primary diazo product are as follows: 4,4'-diaminodiphenylamine-2-sulfonic acid is subjected to a primary diazotization reaction to obtain the primary diazo product.

[0018] The steps to obtain the primary coupling product are as follows: the primary diazo product is subjected to a primary coupling reaction with a γ acid to obtain the primary coupling product;

[0019] The step of obtaining the secondary diazo product is to subject the primary coupling product to a secondary diazotization reaction to obtain the secondary diazo product.

[0020] The steps to obtain the secondary coupling product are as follows: the secondary diazo product is subjected to a secondary coupling reaction with the coupling component to obtain a black direct dye solution.

[0021] According to the preparation method of the present invention, the step of obtaining the primary diazo product includes: mixing 4,4'-diaminodiphenylamine-2-sulfonic acid with nitrite under acidic conditions to carry out a primary diazotization reaction to obtain the primary diazo product;

[0022] Preferably, the temperature of the first diazotization reaction is 0–10°C, and the time of the first diazotization reaction is 1–3 hours.

[0023] According to the preparation method of the present invention, the step of obtaining the primary coupling product includes: mixing the primary diazo product with a γ acid solution, adjusting the pH value to above 8, and performing a primary coupling reaction to obtain the primary coupling product.

[0024] Preferably, the primary diazo product is added to the γ-acid solution by dropwise addition;

[0025] More preferably, the temperature of the first coupling reaction is 0-10°C, and the time of the first coupling reaction is 5-10 hours.

[0026] More preferably, the γ-acid solution is an aqueous solution of γ-acid with a pH value of 7 to 8.

[0027] According to the preparation method of the present invention, the step of obtaining the secondary diazo product includes: under acidic conditions, mixing the primary coupling product with nitrite to carry out a secondary diazotization reaction to obtain the secondary diazo product;

[0028] Preferably, the temperature of the secondary diazotization reaction is 0–10°C, and the time of the secondary diazotization reaction is 1–3 hours.

[0029] According to the preparation method of the present invention, the step of obtaining the secondary coupling product includes: mixing the secondary diazo product with the coupling component solution, adjusting the pH value to above 8, and carrying out a secondary coupling reaction to obtain a black direct dye solution.

[0030] Preferably, the secondary diazo product is added to the coupling component solution by dropwise addition;

[0031] More preferably, the temperature of the secondary coupling reaction is 10–20°C, and the time of the secondary coupling reaction is 3–5 hours.

[0032] According to the preparation method of the present invention, the coupling component solution is an aqueous solution of the coupling component with a pH value of 7 to 8;

[0033] Preferably, the coupling component comprises 2,4-diaminobenzenesulfonate or a combination of 2,4-diaminobenzenesulfonate and m-diphenylamine.

[0034] In addition, the present invention also provides the use of the black direct dye according to the present invention or the black direct dye prepared by the preparation method according to the present invention for dyeing and / or printing fabrics.

[0035] The effects of the invention

[0036] The black direct dye of this invention has a bright and vivid color, good solubility, high color fastness, is environmentally friendly (aniline-free), and has excellent dyeing performance.

[0037] The method for preparing the black direct dye of the present invention generates less wastewater, is environmentally friendly, and is conducive to achieving clean production. Detailed Implementation

[0038] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0039] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0040] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0041] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0042] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0043] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0044] <First Aspect>

[0045] A first aspect of the present invention provides a black direct dye comprising a compound represented by formula (I):

[0046]

[0047] Among them, R1, R2, R3, R4, R5, and R6 are each independently H, -SO3M, or -NH2, and R1, R2, R3, R4, R5, and R6 are not simultaneously H; furthermore, when R1 and R4 are -NH2, R2, R3, R5, and R6 are not simultaneously H, and when R3 and R5 are -NH2, R1, R2, R4, and R6 are not simultaneously H.

[0048] M is H or an alkali metal element, such as common alkali metal elements like Na and K.

[0049] The black direct dye of this invention has a greenish tint and is bright, with good solubility, high color fastness, and is environmentally friendly (aniline-free) with excellent dyeing performance.

[0050] Preferably, the black direct dye of the present invention comprises a combination of two or more compounds having the above formula (I). The inventors of the present invention have discovered that by using a combination of two or more compounds having the above formula (I), a black direct dye with better lightfastness, better solubility, and better market appeal can be obtained.

[0051] Specifically, in this invention, the black direct dye comprises one or more of the compounds shown in formulas (I-1) to (I-3) below:

[0052]

[0053] More specifically, in this invention, the black direct dye comprises a combination of two or more compounds represented by formulas (I-1) to (I-3) or formula (II):

[0054]

[0055]

[0056] <Second aspect>

[0057] A second aspect of the present invention provides a method for preparing a black direct dye according to the first aspect, comprising the following steps:

[0058] The steps to obtain the primary diazo product are as follows: 4,4'-diaminodiphenylamine-2-sulfonic acid is subjected to a primary diazotization reaction to obtain the primary diazo product.

[0059] The steps to obtain the primary coupling product are as follows: the primary diazo product is subjected to a primary coupling reaction with a γ acid to obtain the primary coupling product;

[0060] The step of obtaining the secondary diazo product is to subject the primary coupling product to a secondary diazotization reaction to obtain the secondary diazo product.

[0061] The steps to obtain the secondary coupling product are as follows: the secondary diazo product is subjected to a secondary coupling reaction with the coupling component to obtain a black direct dye solution.

[0062] The method for preparing the black direct dye of the present invention produces less wastewater and causes less environmental pollution, which is conducive to achieving clean production.

[0063] Steps to obtain a primary diazo product

[0064] This invention obtains a primary diazo product by subjecting 4,4'-diaminodiphenylamine-2-sulfonic acid to a primary diazotization reaction.

[0065] In some specific embodiments, the step of obtaining the primary diazo product includes: mixing 4,4'-diaminodiphenylamine-2-sulfonic acid with nitrite under acidic conditions to carry out a primary diazotization reaction to obtain the primary diazo product.

[0066] The present invention does not impose any particular limitation on the mixing method of 4,4'-diaminodiphenylamine-2-sulfonic acid and nitrite, and the mixing can be carried out as needed.

[0067] In some specific implementations, 4,4'-diaminodiphenylamine-2-sulfonic acid can be mixed with water, and then an acidic substance can be added to form a mixed solution of 4,4'-diaminodiphenylamine-2-sulfonic acid and the acidic substance. This solution is then mixed with nitrite for a diazotization reaction. The nitrite can be used in the form of a nitrite solution. Specifically, the nitrite can be dissolved in water to obtain a nitrite solution.

[0068] Further, a nitrite solution is added dropwise to a mixed solution of 4,4'-diaminodiphenylamine-2-sulfonic acid and an acidic substance to initiate a primary diazotization reaction. To make the primary diazotization reaction more efficient, the mixed solution can be cooled before adding the nitrite solution. The cooling method is not particularly limited; the mixed solution can be cooled using ice, an ice-water mixture, or by placing it in a refrigerator. Specifically, the temperature at which the nitrite solution is added to the mixed solution is not particularly limited and is generally below 10°C, for example, 0-8°C, such as 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, etc.

[0069] The acidic substance is not particularly limited, as long as it can satisfy the chemical reaction. Specifically, commonly used acidic substances in the art can be used, such as strong inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and hydrobromic acid. The amount of acidic substance added is not particularly limited in this invention, and it can be added according to the reaction formula.

[0070] Furthermore, the temperature of the first diazotization reaction is 0 to 10°C, for example, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, etc.; the time of the first diazotization reaction is 1 to 3 hours, for example, 1.5h, 5h, 2.5h, etc.

[0071] The present invention does not specifically limit the use of nitrites, and any nitrite commonly used in the art can be used, such as sodium nitrite, potassium nitrite, etc.

[0072] In this invention, taking sodium nitrite as an example: the reaction formula between 4,4'-diaminodiphenylamine-2-sulfonic acid and sodium nitrite can be:

[0073]

[0074] Steps to obtain a primary coupling product

[0075] This invention obtains a primary coupling product by performing a primary coupling reaction between the aforementioned primary diazo product and a γ-acid. The γ-acid described in this invention is 2-amino-8-naphthol-6-sulfonic acid.

[0076] In some specific implementations, the step of obtaining the primary coupling product includes: mixing the primary diazo product with a γ-acid solution, adjusting the pH value to above 8, such as 9, 10, 11, 12, 13, etc., and performing a primary coupling reaction to obtain the primary coupling product.

[0077] In some specific embodiments, the γ-acid solution is an aqueous solution of γ-acid with a pH value of 7-8, such as 7.2, 7.4, 7.6, 7.8, etc. Specifically, the γ-acid is dissolved in water, and the pH value of the system is adjusted to 7-8 using an alkaline substance, and the solution is obtained after dissolution.

[0078] In some specific embodiments, the primary diazo product is added to the γ-acid solution dropwise. To make the reaction more efficient, the γ-acid solution can be cooled first, and then the primary diazo product can be added dropwise to the γ-acid solution. The present invention does not particularly limit the cooling method; any feasible method can be used to cool the γ-acid solution. Specifically, the present invention does not particularly limit the temperature at which the primary diazo product is added to the γ-acid solution; it is generally below 10°C, for example: 0-10°C, such as 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, etc.

[0079] Furthermore, the temperature of the first coupling reaction is 0 to 10°C, for example, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, etc.; the time of the first coupling reaction is 5 to 10 hours, for example, 6 hours, 7 hours, 8 hours, 9 hours, etc.

[0080] In some specific implementations, an alkaline substance can be used to adjust the pH value to above 8. The present invention does not specifically limit the alkaline substance used; any alkaline substance commonly used in the art for adjusting pH can be used, such as liquid alkali, potassium hydroxide, ammonia, sodium carbonate, potassium carbonate, etc.

[0081] Taking the sodium diazonium salt of 4,4'-diaminodiphenylamine-2-sulfonic acid as an example, a further coupling reaction with a γ-acid can be carried out, and the reaction formula can be:

[0082]

[0083] Steps to obtain secondary diazo products

[0084] The present invention obtains a secondary diazo product by subjecting the above-mentioned primary coupling product to a secondary diazo reaction.

[0085] In some specific implementations, the step of obtaining the secondary diazo product includes: mixing the primary coupling product with nitrite under acidic conditions to carry out a secondary diazotization reaction to obtain the secondary diazo product.

[0086] The present invention does not impose any particular limitation on the mixing method of the primary coupling product and nitrite, and the mixing can be carried out as needed.

[0087] In some specific implementations, to facilitate the reaction, the acidic substance can be mixed with the primary coupling product to form a mixed solution of the primary coupling product and the acidic substance, which is then mixed with nitrite to carry out a secondary diazotization reaction. The nitrite can be used in the form of a nitrite solution. Specifically, the nitrite can be dissolved in water to obtain a nitrite solution.

[0088] Furthermore, a nitrite solution is added dropwise to the mixture of the primary coupling product and the acidic substance to initiate a secondary diazotization reaction. To make the secondary diazotization reaction more efficient, the mixed solution can be cooled before adding the nitrite solution. The cooling method is not particularly limited; the primary coupling product solution can be cooled using ice, an ice-water mixture, or by placing it in a refrigerator. Specifically, the temperature at which the nitrite solution is added to the mixed solution is not particularly limited and is generally below 10°C, for example, 0-8°C, such as 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, etc.

[0089] Furthermore, the temperature of the secondary diazotization reaction is 0–10°C, for example, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, etc.; the time of the secondary diazotization reaction is 1–3 hours, for example, 1.5h, 5h, 2.5h, etc.

[0090] The present invention does not specifically limit the use of nitrites, and any nitrite commonly used in the art can be used, such as sodium nitrite, potassium nitrite, etc.

[0091] In this invention, sodium nitrite is used as an example: the primary coupling product obtained after reacting the sodium diazonium salt of 4,4'-diaminodiphenylamine-2-sulfonic acid with γ-acid undergoes a secondary diazotization reaction with sodium nitrite, and the reaction formula can be:

[0092]

[0093] Steps to obtain secondary coupling products

[0094] The present invention obtains a black direct dye solution by performing a secondary coupling reaction between the obtained secondary diazo product and the coupling component.

[0095] In some specific implementations, the step of obtaining the secondary coupling product includes: mixing the secondary diazo product with the coupling component solution, adjusting the pH of the system to above 8, such as 9, 10, 11, 12, 13, etc., to carry out a secondary coupling reaction and obtain a black direct dye solution.

[0096] In some specific implementations, the coupling component solution is an aqueous solution of the coupling component with a pH value of 7-8, such as 7.2, 7.4, 7.6, 7.8, etc. Specifically, the coupling component is dissolved in water, and the pH value of the system is adjusted to 7-8 using an alkaline substance. After dissolution, the coupling component solution is obtained.

[0097] Furthermore, the coupling component used in this invention includes 2,4-diaminobenzenesulfonate, or a combination of 2,4-diaminobenzenesulfonate and m-diphenylamine. Preferably, 2,4-diaminobenzenesulfonate can be a m-disodium salt (i.e., sodium 2,4-diaminobenzenesulfonate) or potassium 2,4-diaminobenzenesulfonate.

[0098] In some specific embodiments, the secondary diazo product is added to the coupling component solution dropwise. To make the reaction more efficient, the coupling component solution can be cooled first, and then the secondary diazo product can be added dropwise to the coupling component solution. The present invention does not particularly limit the cooling method; any feasible method can be used to cool the coupling component solution. Specifically, the present invention does not particularly limit the temperature at which the secondary diazo product is added to the coupling component solution; it is generally 20-30°C, for example: 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, etc.

[0099] Furthermore, the temperature of the secondary coupling reaction is 10–20°C, for example, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, etc.; the time of the secondary coupling reaction is 3–5 hours, for example, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, etc.

[0100] In some specific implementations, the pH value of the system is adjusted using an alkaline substance. The present invention does not specifically limit the alkaline substance used; commonly used alkaline substances for pH adjustment in the art can be used, such as liquid alkali, potassium hydroxide, ammonia, sodium carbonate, potassium carbonate, etc.

[0101] In this invention, when the coupling component used is a meta-disodium salt, taking the diazonium sodium salt of the primary coupling product obtained by reacting the diazonium sodium salt of 4,4'-diaminodiphenylamine-2-sulfonic acid with γ-acid as an example, a secondary coupling reaction is carried out with the meta-disodium salt. The reaction formula can be:

[0102]

[0103] When the coupling component used is a combination of m-disodium salt and m-diphenylamine, taking the diazonium salt of the primary coupling product obtained by reacting the diazonium salt of 4,4'-diaminodiphenylamine-2-sulfonic acid with γ-acid as an example, a secondary coupling reaction is carried out with the combination of m-disodium salt and m-diphenylamine. The reaction formula can be:

[0104]

[0105] In some specific implementations, the step of drying the black direct dye solution may also be included. The present invention does not particularly limit the drying method, which may be spray drying commonly used in the art.

[0106] <Third aspect>

[0107] A third aspect of the present invention provides the use of a black direct dye prepared according to the first aspect or the preparation method according to the second aspect for dyeing and / or printing fabrics.

[0108] Example

[0109] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0110] Example 1

[0111] (1) Add 100g of water to a beaker, then add 33.5g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 300g of water to a three-necked flask, then add 65g of 4,4'-diaminodiphenylamine-2-sulfonic acid. After stirring, add 60g of hydrochloric acid. Stir for 1 hour, then add 300g of an ice-water mixture to cool the mixture. Slowly add the sodium nitrite solution dropwise, keeping the system temperature at 3°C ​​during the dropwise addition. After the dropwise addition is complete, maintain the system temperature at 5°C and react for 1.5 hours. After the reaction is complete, a primary diazo product is obtained.

[0112] (2) Dissolve 102g of γ-acid in 700g of water, stir for 1h, and then adjust the pH of the system to 8.0 with a 30% (w / w) liquid alkali solution to obtain a γ-acid solution. Cool the γ-acid solution to 5℃, and add the primary diazo product dropwise to the γ-acid solution. After the addition is complete, adjust the pH of the system to 8 with a 30% (w / w) liquid alkali solution. Keep the system temperature at 0℃ and react for 8h. After the reaction is complete, a primary coupling product is obtained.

[0113] (3) Add 100g of water to a beaker, then add 31g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 260g of 30% hydrochloric acid solution to the primary coupling product, stir evenly, lower the system temperature to 0℃, and then add the obtained sodium nitrite solution dropwise. After the addition is complete, keep the temperature at 0℃ for 2 hours to obtain the secondary diazo product.

[0114] (4) Place 300g of bottom water in a beaker, add 78g of meta-disodium salt and stir until completely dissolved to obtain a meta-disodium salt solution. Adjust the pH of the system to 8 using a 30% (w / w) liquid alkali solution, and cool the system to 20°C for later use. Turn on the stirrer and add the secondary diazo product obtained in (3) to the meta-disodium salt solution for coupling reaction. After the addition is complete, maintain the pH of the system at 7 and the temperature at 10°C for 4 hours. After the reaction is completed, a black direct dye solution is obtained. The black direct dye solution is directly spray-dried to obtain the finished black direct dye product, whose structural formula is shown in (I-2), denoted as S1.

[0115] Example 2

[0116] (1) Add 100g of water to a beaker, then add 33.5g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 300g of water to a three-necked flask, then add 65g of 4,4'-diaminodiphenylamine-2-sulfonic acid. After stirring, add 60g of hydrochloric acid. Stir for 1 hour, then add 300g of an ice-water mixture to cool the mixture. Slowly add the sodium nitrite solution dropwise, keeping the system temperature at 3°C ​​during the dropwise addition. After the dropwise addition is complete, maintain the system temperature at 5°C and react for 1.5 hours. After the reaction is complete, a primary diazo product is obtained.

[0117] (2) Dissolve 102g of γ-acid in 700g of water, stir for 1h, and then adjust the pH of the system to 8.0 with a 30% (w / w) liquid alkali solution to obtain a γ-acid solution. Cool the γ-acid solution to 5℃, and add the primary diazo product dropwise to the γ-acid solution. After the addition is complete, adjust the pH of the system to 8 with a 30% (w / w) liquid alkali solution. Keep the system temperature at 0℃ and react for 8h. After the reaction is complete, a primary coupling product is obtained.

[0118] (3) Add 100g of water to a beaker, then add 31g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 260g of 30% hydrochloric acid solution to the primary coupling product, stir evenly, lower the system temperature to 0℃, and then add the obtained sodium nitrite solution dropwise. After the addition is complete, keep the temperature at 0℃ for 2 hours to obtain the secondary diazo product.

[0119] (4) Place 300g of bottom water in a beaker, add 39g of m-disodium salt and 20g of m-phenylenediamine, and stir until completely dissolved to obtain a mixed solution of m-disodium salt and m-phenylenediamine. Adjust the pH of the system to 8 using a 30% liquid alkali solution, and cool the system to 20℃ for later use. Turn on the stirrer, add the secondary diazo product obtained in (3) to the mixed solution of m-disodium salt and m-phenylenediamine for coupling reaction. After the addition is complete, keep the pH of the system at 7 and the temperature at 10℃ for 4 hours. After the reaction is completed, a black direct dye solution is obtained. The black direct dye solution is directly spray-dried to obtain the finished black direct dye product, whose structural formula is shown in formulas (I-1)-(I-3) and (II), and is denoted as S2.

[0120] Example 3

[0121] (1) Add 100g of water to a beaker, then add 33.5g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 300g of water to a three-necked flask, then add 65g of 4,4'-diaminodiphenylamine-2-sulfonic acid. After stirring, add 60g of hydrochloric acid. Stir for 1 hour, then add 300g of an ice-water mixture to cool the mixture. Slowly add the sodium nitrite solution dropwise, keeping the system temperature at 8°C during the dropwise addition. After the dropwise addition is complete, maintain the system temperature at 5°C and react for 1.5 hours. After the reaction is complete, a primary diazo product is obtained.

[0122] (2) Dissolve 102g of γ-acid in 700g of water and stir for 1h. Then adjust the pH of the system to 8 with a 30% (w / w) liquid alkali solution and dissolve until clear to obtain a γ-acid solution. Cool the γ-acid solution to 5℃ and add the primary diazo product dropwise to the γ-acid solution. After the addition is complete, adjust the pH of the system to 8 with a 30% (w / w) liquid alkali solution. Keep the system temperature at 0℃ and react for 10h. After the reaction is complete, a primary coupling product is obtained.

[0123] (3) Add 100g of water to a beaker, then add 31g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 260g of 30% hydrochloric acid solution to the primary coupling product, stir evenly, lower the system temperature to 0℃, and then add the obtained sodium nitrite solution dropwise. After the addition is complete, keep the temperature at 0℃ for 2 hours to obtain the secondary diazo product.

[0124] (4) Place 300g of bottom water in a beaker, add 78g of meta-disodium salt and stir until completely dissolved to obtain a meta-disodium salt solution. Adjust the pH of the system to 8 using a 30% (w / w) liquid alkali solution, and cool the system to 20°C for later use. Turn on the stirrer and add the secondary diazo product obtained in (3) to the meta-disodium salt solution for coupling reaction. After the addition is complete, maintain the pH of the system at 7 and the temperature at 10°C for 4 hours. After the reaction is completed, a black direct dye solution is obtained. The black direct dye solution is directly spray-dried to obtain the finished black direct dye product, whose structural formula is shown in (I-2), denoted as S3.

[0125] Example 4

[0126] (1) Add 100g of water to a beaker, then add 33.5g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 300g of water to a three-necked flask, then add 65g of 4,4'-diaminodiphenylamine-2-sulfonic acid. After stirring, add 60g of hydrochloric acid. Stir for 1 hour, then add 300g of an ice-water mixture to cool the mixture. Slowly add the sodium nitrite solution dropwise, keeping the system temperature at 0℃ during the dropwise addition. After the dropwise addition is complete, keep the system temperature at 0℃ and react for 1.5 hours. After the reaction is complete, a primary diazo product is obtained.

[0127] (2) Dissolve 102g of γ-acid in 700g of water, stir for 1h, and then adjust the pH of the system to 8.0 with a 30% (w / w) liquid alkali solution to obtain a γ-acid solution. Cool the γ-acid solution to 5℃, and add the primary diazo product dropwise to the γ-acid solution. After the addition is complete, adjust the pH of the system to 8 with a 30% (w / w) liquid alkali solution. Keep the system temperature at 0℃ and react for 10h. After the reaction is complete, a primary coupling product is obtained.

[0128] (3) Add 100g of water to a beaker, then add 31g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 260g of 30% hydrochloric acid solution to the primary coupling product, stir evenly, lower the system temperature to 0℃, and then add the obtained sodium nitrite solution dropwise. After the addition is complete, keep the temperature at 0℃ for 2 hours to obtain the secondary diazo product.

[0129] (4) Place 300g of bottom water in a beaker, add 39g of m-disodium salt and 20g of m-phenylenediamine, and stir until completely dissolved to obtain a mixed solution of m-disodium salt and m-phenylenediamine. Adjust the pH of the system to 8 using a 30% liquid alkali solution, and cool the system to 20℃ for later use. Turn on the stirrer, add the secondary diazo product obtained in (3) to the mixed solution of m-disodium salt and m-phenylenediamine for coupling reaction. After the addition is complete, keep the pH of the system at 7 and the temperature at 10℃ for 4 hours. After the reaction is completed, a black direct dye solution is obtained. The black direct dye solution is directly spray-dried to obtain the finished black direct dye product, whose structural formula is shown in formulas (I-1)-(I-3) and (II), and is denoted as S4.

[0130] Comparative Example 1

[0131] (1) Add 100g of water to a beaker, then add 33.5g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 300g of water to a three-necked flask, then add 65g of 4,4'-diaminodiphenylamine-2-sulfonic acid. After stirring, add 60g of hydrochloric acid. Stir for 1 hour, then add 300g of an ice-water mixture to cool the mixture. Slowly add the sodium nitrite solution dropwise, keeping the system temperature at 3°C ​​during the dropwise addition. After the dropwise addition is complete, maintain the system temperature at 5°C and react for 1.5 hours. After the reaction is complete, a primary diazo product is obtained.

[0132] (2) Dissolve 102g of γ-acid in 700g of water, stir for 1h, and then adjust the pH of the system to 8.0 with a 30% (w / w) liquid alkali solution to obtain a γ-acid solution. Cool the γ-acid solution to 5℃, and add the primary diazo product dropwise to the γ-acid solution. After the addition is complete, adjust the pH of the system to 8 with a 30% (w / w) liquid alkali solution. Keep the system temperature at 0℃ and react for 8h. After the reaction is complete, a primary coupling product is obtained.

[0133] (3) Add 100g of water to a beaker, then add 31g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 260g of 30% hydrochloric acid solution to the primary coupling product, stir evenly, lower the system temperature to 0℃, and then add the obtained sodium nitrite solution dropwise. After the addition is complete, keep the temperature at 0℃ for 2 hours to obtain the secondary diazo product.

[0134] (4) Place 300g of water in a beaker, add 40g of m-phenylenediamine and stir until completely dissolved to obtain a m-phenylenediamine solution. Adjust the pH of the system to 8 using a 30% (w / w) liquid alkali solution, and cool the system to 20°C for later use. Turn on the stirrer and add the secondary diazo product obtained in (3) to the m-phenylenediamine solution for coupling reaction. After the addition is complete, maintain the pH of the system at 7 and the temperature at 10°C for 4 hours. After the reaction is complete, a black direct dye solution is obtained. The black direct dye solution is directly spray-dried to obtain the finished black direct dye product, denoted as D1.

[0135] Comparative Example 2

[0136] (1) Add 100g of water to a beaker, then add 44g of sodium nitrite. Stir until completely dissolved to obtain a sodium nitrite solution, and let it stand for later use. Add 600g of water to a three-necked flask, then add 84g of p-nitroaniline. Stir for 2 hours, then add 170g of concentrated hydrochloric acid. Cool to 0℃, add 100g of crushed ice, and then proceed with the diazo reaction. Add the dissolved sodium nitrite solution to the three-necked flask at a rate that is fast at first and then slow, keeping the starch-potassium iodide test paper and Congo red test paper blue, at a temperature of 0℃, and over a time of 5 minutes. After the addition is complete, maintain the temperature at 0℃ and stir for 2 hours. After the reaction is complete, the diazo product is obtained, and the temperature is maintained at around 3℃ for later use.

[0137] (2) Add 1000g of water to a beaker, then add 115g of H acid. Stir for half an hour and adjust the pH of the system to 5.5 with liquid alkali. After dissolving, obtain the H acid solution. Then cool to 5℃ and quickly add the H acid solution to the diazo product obtained in (1). After adding, keep the system temperature at 5℃ and adjust the pH of the system to 4 with sodium bicarbonate. Stir the reaction for 8 hours to obtain the coupling product, and let it stand for later use.

[0138] (3) Add 300g of water to a beaker, heat to 35℃, add 115g of sodium sulfide and stir until dissolved without lumps to obtain a sodium sulfide solution, and let it stand for later use. Adjust the temperature of the coupling product obtained in (2) to 15℃ and add it to the sodium sulfide solution. Control the system temperature at 20℃ during the addition. After the addition is complete, keep the system temperature at 35℃ and react for 2 hours. After 2 hours, the reaction reaches the endpoint and a black solution is obtained.

[0139] (4) Add 100g of water to a beaker, then add 40g of sodium nitrite and stir until completely dissolved to obtain a sodium nitrite solution. Add the sodium nitrite solution to the black solution and stir. Adjust the pH of the system to 11, then add 165g of hydrochloric acid. While stirring, maintain the system temperature at 5℃. After 6 hours of incubation, the reaction reaches the endpoint and the reaction product is obtained.

[0140] (5) Add 100g of water to a beaker and then add 47g of m-phenylenediamine. Stir until completely dissolved to obtain a m-phenylenediamine solution. Adjust the pH of the reaction product system obtained in (4) to 6.0 and then quickly add it to the m-phenylenediamine solution while maintaining the pH of the system at 7. Stir the reaction for 6 hours to reach the endpoint. After salting out the product, the black direct dye product is obtained and denoted as D2.

[0141] Staining methods

[0142] Take 1g of each of the black direct dyes obtained in Examples 1-4 and Comparative Examples 1-2, 100g of cotton fabric and 2g of sodium sulfate and place them in hot water at 40℃. After stirring evenly, raise the temperature to 98-100℃ at a rate of 1℃ / min and add another 10g of sodium sulfate. After stirring evenly, keep warm for 45min, then gradually lower the temperature to 70℃, wash thoroughly with water and dry directly.

[0143] Performance testing

[0144] The solubility, rubbing resistance, wash resistance, perspiration resistance, light fastness, and sunlight fastness of the dried dyed fabrics were determined, and the dyeing depth and dyeing rate were calculated. The methods used were in accordance with GB / T21879-2015, GB / T 3920-2008, GB / T 5713-2013, GB / T 3922-2013, GB / T8427-1998, and GB / T 8426-1998, respectively. Simultaneously, 50g of the dyeing wastewater was taken to measure the Abs value and COD value of the wastewater. The methods used were the UV-Vis spectrophotometer method (wavelength 380nm~750nm) and the GB11914-89 chemical oxygen demand-dichromate method, respectively. The dye properties obtained in Examples 1-4 and Comparative Examples 1-2 are shown in Table 1 below.

[0145] Table 1

[0146]

[0147] Note: / indicates that it was not detected.

[0148] As can be seen from Table 1, the dyeing depth of the black direct dyes prepared in Examples 1-4 is the same as that of the black direct dyes obtained in the comparative examples, which meets the requirements of the product. At the same time, the dye uptake rate and solubility of the dyes in the examples are higher than those in the comparative examples, indicating that dye waste can be reduced, the uniformity of subsequent dyeing can be improved, the dyeing time can be shortened, and the product's market competitiveness can be enhanced.

[0149] In terms of dyeing performance, the dyes in Examples 1-4 all showed better dyeing performance than the dyes in the comparative examples, indicating that the dyes prepared in the examples had superior dyeing performance in all aspects.

[0150] Meanwhile, regarding wastewater, neither Abs nor COD was detected in the product wastewater of Examples 1-4 and Comparative Example 1, while both were present in Comparative Example 2. This proves that the dye prepared by this method produces no wastewater, saving subsequent wastewater treatment costs and also avoiding environmental pollution.

[0151] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0152] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A black direct dye, characterized in that, It includes combinations of compounds represented by formulas (I-1) to (I-3) and formula (II): （Ⅰ-1） （Ⅰ-2） （Ⅰ-3） （Ⅱ）。 2. A method for preparing a black direct dye according to claim 1, characterized in that, Includes the following steps: The steps to obtain the primary diazo product are as follows: 4,4'-diaminodiphenylamine-2-sulfonic acid is subjected to a primary diazotization reaction to obtain the primary diazo product. The steps to obtain the primary coupling product are as follows: the primary diazo product is subjected to a primary coupling reaction with a γ acid to obtain the primary coupling product; The step of obtaining the secondary diazo product is to subject the primary coupling product to a secondary diazotization reaction to obtain the secondary diazo product. The steps to obtain the secondary coupling product are as follows: the secondary diazo product is subjected to a secondary coupling reaction with the coupling component to obtain a black direct dye solution.

3. The preparation method according to claim 2, characterized in that, The step of obtaining the primary diazo product includes: mixing 4,4'-diaminodiphenylamine-2-sulfonic acid with nitrite under acidic conditions to carry out a primary diazotization reaction to obtain the primary diazo product.

4. The preparation method according to claim 3, characterized in that, The temperature of the first diazotization reaction is 0~10℃, and the time of the first diazotization reaction is 1~3 hours.

5. The preparation method according to any one of claims 2 to 4, characterized in that, The step of obtaining the primary coupling product includes: mixing the primary diazo product with a γ-acid solution, adjusting the pH value to above 8, and performing a primary coupling reaction to obtain the primary coupling product.

6. The preparation method according to claim 5, characterized in that, The primary diazo product is added to the γ-acid solution by dropwise addition.

7. The preparation method according to claim 6, characterized in that, The temperature of the first coupling reaction is 0~10℃, and the time of the first coupling reaction is 5~10 hours.

8. The preparation method according to claim 7, characterized in that, The γ-acid solution is an aqueous solution of γ-acid with a pH value of 7-8.

9. The preparation method according to any one of claims 2 to 4, characterized in that, The step of obtaining the secondary diazo product includes: under acidic conditions, mixing the primary coupling product with nitrite to carry out a secondary diazotization reaction to obtain the secondary diazo product.

10. The preparation method according to claim 9, characterized in that, The temperature of the secondary diazotization reaction is 0~10℃, and the time of the secondary diazotization reaction is 1~3 hours.

11. The preparation method according to any one of claims 2 to 4, characterized in that, The step of obtaining the secondary coupling product includes: mixing the secondary diazo product with the coupling component solution, adjusting the pH value to above 8, and carrying out a secondary coupling reaction to obtain a black direct dye solution.

12. The preparation method according to claim 11, characterized in that, The secondary diazo product is added to the coupling component solution by dropwise addition.

13. The preparation method according to claim 12, characterized in that, The temperature of the secondary coupling reaction is 10~20℃, and the time of the secondary coupling reaction is 3~5h.

14. The preparation method according to any one of claims 2 to 4, characterized in that, The coupling component solution is an aqueous solution of the coupling component with a pH value of 7-8.

15. The preparation method according to claim 14, characterized in that, The coupling component comprises a combination of 2,4-diaminobenzenesulfonate and m-phenylenediamine.

16. Use of a black direct dye according to claim 1 or a black direct dye prepared by any one of claims 2 to 15 for dyeing and / or printing fabrics.

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