Dyeing method for improving color fastness of spandex based on disperse blue dye

Abstract

The invention discloses a dyeing method for improving color fastness of spandex based on disperse blue dye, and belongs to the technical field of dye manufacturing and application. The invention provides a dyeing method for improving the color fastness of spandex based on a specific disperse blue dye, and the disperse blue dye has the advantages of high dye-uptake, good washing fastness, high redyeing property, wide pH application range and conformity to environment-friendly printing and dyeing.

Description

Technical Field

[0001] This invention belongs to the field of dye manufacturing and application technology, and specifically relates to a dyeing method for improving the color fastness of spandex based on disperse blue dye. Background Technology

[0002] Disperse dyes theoretically form strong bonds with spandex, especially polyester spandex, and in some cases, even through hydrogen bonds. However, due to the soft and hard microphase structure of spandex, while disperse dyes readily adsorb onto spandex, they are also prone to desorption. This is because currently available disperse dyes are primarily designed for polyester dyeing, resulting in smaller molecular structures and fewer polar groups. When dyes with these structural characteristics are used in spandex dyeing, although they diffuse easily within the spandex, they struggle to form strong bonds with the soft segments of the spandex. The end result is low dye uptake, and under humid and hot conditions, the dye is also relatively easy to desorb. Therefore, in most cases, this characteristic of disperse dyes severely affects the colorfastness of spandex, necessitating the addition of anti-staining agents to improve the colorfastness of spandex dyeing.

[0003] The dyeing process for polyester / spandex blends varies depending on the spandex content. For example, for core-spun and covered yarns where spandex is not easily exposed, only appropriate dyeing is needed. However, for blends with a high spandex content or those frequently under stretching, a low spandex dyeing rate will cause color differences and significantly reduce the color uniformity of the blend. Therefore, the dyeing requirements of various fibers must be fully considered when dyeing polyester / spandex blends.

[0004] Azo disperse blue dyes have a wide range of colors, including yellow, orange, red, and blue, and a complete color spectrum. They also have high color intensity, so they hold a very important position in the market and are the most produced azo disperse dyes. However, they are not very suitable for dyeing polyester-spandex blends, especially blends with high spandex content. Only a small amount of disperse blue dyes can be used, such as disperse blue BBLS, disperse blue SE-2R, disperse deep blue HGL, and disperse blue EX-SF (Qian Hongfei, Dye Industry, 2000, 37(2)).

[0005]

[0006] Other reports indicate that anthraquinone disperse blues such as Disperse Blue 2BLN (Che Jiangning, Dyeing and Printing, 1999(8)), Disperse Turquoise Blue GL, and Disperse Deep Blue BFLS are suitable for dyeing polyester-ammonia blends (CN202011362301.0).

[0007]

[0008] The structures of azo disperse dyes reveal that the N,N-substituents are alkyl groups, whose hydrophobic properties facilitate the binding of the dye to the hydrophobic microdomains of spandex via van der Waals forces. The N,N-substituents are ester groups, whose polarity helps the dye bind to the ester or ether groups in the soft segments of spandex via dipole forces. Anthraquinone dyes primarily benefit from the ability of their C=O and -NH2 groups to form hydrogen bonds with the amide groups (-NH-CO-) and ether bonds (-O-) on the spandex molecular chain, thus enhancing fixation.

[0009] However, data shows that the dyeing uptake of Disperse Blue BBLS is only 42.6%, Disperse Blue SE-2R is only 37.5%, Disperse Deep Blue HGL is 84.7%, and Disperse Blue EX-SF is 44.4%. Similarly, the dyeing uptake of anthraquinone dyes also fluctuates significantly, such as Disperse Blue 2BLN at 84.5%, Disperse Turquoise Blue GL at 50%, and Disperse Deep Blue BFLS at 84.7%. The reason for this is that these disperse dyes, which are more suitable for dyeing polyester-spandex blends, have many problems, such as easy desorption, low dyeing uptake, poor fastness, narrow pH range, easy hydrolysis, and failure to meet environmental protection requirements for printing and dyeing.

[0010] Based on the above, finding a disperse blue dye that can dye spandex under a wide pH range, with high dyeing rate and good fastness is a technical problem that urgently needs to be solved. Summary of the Invention

[0011] [Technical Issues] (1) The soft segment region (ether chain / ester chain) of spandex is loose, making it easy for dyes to enter and exit. The hard segment has high crystallinity, making it difficult for dyes to enter and bind. Therefore, the binding force between dyes and spandex is relatively weak, mainly due to physical adsorption. Even Disperse Blue HGL and Disperse Blue BFLS, which have a better binding force with spandex, are bound to spandex by van der Waals forces and hydrogen bonds. In a humid and hot environment, they can easily fall off the fiber.

[0012] (2) The above dyes can only be used in the pH range of 4 to 7. Most of the acetamino groups, ester groups, cyano groups in disperse blue dyes will hydrolyze and fade under higher pH conditions, so the re-dyeing ability is poor.

[0013] (3) Although anthraquinone dyes are superior to azo dyes in terms of color and chemical stability, they have poor fastness to wet heat treatment because the dyes are mainly bonded to spandex through weak van der Waals forces and hydrogen bonds, lacking strong chemical bonds, and are easy to fall off the fiber.

[0014] (4) Alkali-resistant dyes can achieve a one-bath process of "removal, scouring, and dyeing" or a one-bath process of "alkali reduction / dyeing," which is a typical practice of promoting industrial upgrading through technological innovation. The use of alkali-resistant dyes directly responds to the core demands of the current printing and dyeing industry for green, efficient, and high-quality development. However, most disperse dyes do not currently meet the requirements for environmentally friendly printing and dyeing.

[0015] [Technical Solution] To address the above shortcomings, this invention provides a method for preparing and applying disperse blue dyes capable of dyeing polyester-spandex blended fabrics. The dyeing method of this invention offers advantages such as high dye uptake, good wash fastness, high re-dyeing properties, a wide pH range, and compliance with environmentally friendly dyeing and printing standards.

[0016] To achieve the above objectives, the technical solution provided by the present invention is as follows.

[0017] This invention provides a dyeing method for improving the color fastness of spandex based on disperse blue dye, wherein the structure of the disperse blue dye is shown in Formula I:

[0018] Formula I Where M is R1 is -NHCOCH3 or -NHCOCH2CH3; or, M is R1 is -H, -CH3, -CH2CH3, -NHCOCH3, -NHCOCH2CH3; R a R b Each of the following is independently selected from -H, -Cl, -Br, -CN, and -NO2; R2 can be -H, -CH3, -CH2CH3, -CH2CH2CN, or -COCH2COCH3; R3 can be -H, -CH3, -CH2CH3, or -Cl; R4 represents -H, -Cl, and -NO2; n is 0, 1, or 2.

[0019] In one embodiment of the present invention, M is specifically selected from: .

[0020] In one embodiment of the present invention, the disperse blue dye is a monoazo dye, and one of the N,N-substituents in the coupling component is a benzene ring or a benzene ring derivative.

[0021] In one embodiment of the present invention, the disperse blue dye is preferably 10 dyes with the following structure:

[0022] The specific replacement details are as follows: M is ,

[0023] Or, M is ,

[0024] In one embodiment of the present invention, the synthetic route for disperse indigo dyeing is as follows: .

[0025] In one embodiment of the present invention, the method for synthesizing disperse indigo dye includes the following steps:

[0026] Step 1: Synthesize compound II Compound II (also known as the even single component) is obtained by condensation reaction of compounds II-1 and II-2. Step 2: Diazotization When using III-1 as a substrate, a combination of hydrochloric acid and sodium nitrite is used as the diazotizing agent. The III-1 compound is slurried in a mixture of water and hydrochloric acid and cooled to a certain temperature. A 30% sodium nitrite aqueous solution is then added dropwise. After the addition is complete, the mixture is kept at the temperature for a period of time to carry out the diazotization reaction and obtain a diazo solution. Alternatively, when using III-2 as a substrate, a combination of sulfuric acid and nitrosylsulfuric acid is used as the diazotizing agent. The III-2 compound is dissolved in 93% sulfuric acid and cooled to a certain temperature. Then, 40% nitrosylsulfuric acid is added dropwise. After the addition is complete, the mixture is kept at the temperature for a period of time to carry out the diazotization reaction and obtain a diazo solution. Step 3: Synthesize compound with structural formula I Water and 93% sulfuric acid were added to a four-necked flask, along with compound of formula II, aminosulfonic acid or urea, and 0.25 additive. The mixture was stirred until the temperature dropped to a certain level, and then diazonium solution was added dropwise. After the addition was complete, the temperature was kept warm for a period of time. Then the temperature was raised to a certain level and kept warm for a period of time. The mixture was then hot filtered and washed with hot water to obtain the target dye.

[0027] In one embodiment of the present invention, in step 1, the condensation reaction is carried out in a solvent, which is any one or more mixtures of water, acetone, and acetonitrile. The mass of the solvent is 1.5 to 2.5 times the total mass of compounds of formula II-1 and formula II-2.

[0028] In one embodiment of the present invention, in step 1, the molar ratio of compound II-1 and compound II-2 in the reaction is 1:1.05~1.2.

[0029] In one embodiment of the present invention, in step 1, the acid-binding agent used in the reaction is one of sodium bicarbonate, sodium carbonate, and sodium acetate, and its amount is 1.2 to 1.5 times the amount of the compound of structural formula II-1.

[0030] In one embodiment of the present invention, in step 1, the reaction temperature is 60~95℃, preferably 80~85℃, and the holding time is 8~12h.

[0031] In one embodiment of the present invention, in step 1, acetic anhydride is added as a reaction terminator after the reaction is completed, and the amount of acetic anhydride is 5 to 10% of the amount of the compound of structural formula II-1.

[0032] In one embodiment of the present invention, in step 2, when using III-1 as the substrate, in the diazotization reaction, the molar amount of hydrochloric acid is 2.5 to 4 times that of compound M, the molar amount of sodium nitrite is 1.05 to 1.4 times that of compound M, and the amount of water is based on the pH of the entire system being below 2, approximately 1.5 to 2 times the mass of the aromatic amine. The reaction temperature is set at -5 to 10°C, preferably -3 to 3°C. The dropping time of the sodium nitrite aqueous solution is controlled at 0.5 to 1 hour, and after the dropping is completed, the heat preservation time is controlled at 10 minutes to 2 hours.

[0033] In one embodiment of the present invention, in step 2, when III-2 is used as the substrate, in the diazotization reaction, the mass of sulfuric acid is 6 to 10 times the mass of compound M, and the molar amount of nitrosylsulfuric acid is 1.05 to 1.2 times the amount of substance of compound M; the reaction temperature is set at -5 to 10°C, preferably -3 to 3°C; the dropping time of nitrosylsulfuric acid is controlled at 0.5 to 1 hour, and after the dropping is completed, the heat preservation time is controlled at 10 minutes to 2 hours.

[0034] In one embodiment of the present invention, in step 3, the amount of water used in the reaction is 4 to 5 times the sum of the masses of all substances, and the amount of sulfuric acid is determined by the pH value to ensure that the pH of the system is between 3 and 4. The amount of compound of structural formula II is 1.05 to 1.1 times the amount of compound of structural formula M in the diazo solution. The molar amount of urea is 5 to 10% of the amount of sodium nitrite, the amount of aminosulfonic acid is 5 to 10% of the amount of nitrosylsulfonic acid, and the additive Pingpingjia O-25 is used as a dispersant, with an amount of 1 to 2% of the total mass of the system.

[0035] In one embodiment of the present invention, in step 3, the reaction temperature is -5~10℃; In one embodiment of the present invention, in step 3, the diazo liquid is added for about 2 hours, and the temperature is maintained for 2 to 8 hours after the addition is completed. In one embodiment of the present invention, in step 3, after the reaction is completed, the temperature is slowly raised to 60~95°C and kept at that temperature for 2~3 hours; In one embodiment of the present invention, in step 3, after the reaction is completed, the product is hot filtered, washed with hot water until the wash water is colorless, and then dried at 100°C for 12 hours to ensure that the moisture content is less than 0.1%.

[0036] This invention also specifically provides a dyeing method for improving the color fastness of spandex using disperse blue dye, comprising: Azo disperse orange dye, MF (sodium naphthalene sulfonate), sodium lignin sulfonate and water are mixed and ground, then diluted with water to prepare an initial dye bath. The pH of the initial dye bath is adjusted to 4.5-12, and then a leveling agent is added to obtain the dye bath. Finally, polyester-spandex blended fibers are placed in the obtained dye bath for dyeing.

[0037] In one embodiment of the present invention, the mass ratio of azo disperse orange dye to MF is 1:0.5~1.2. Specifically, 1:1 is optional.

[0038] In one embodiment of the present invention, the mass ratio of azo disperse orange dye to sodium lignosulfonate is 1:0.5~0.8. Specifically, 1:0.5 is optional.

[0039] In one embodiment of the present invention, the particles are ground to a particle size of about 500 nm.

[0040] In one embodiment of the present invention, the dispersion concentration of the dye in the initial dye bath is 1% to 3%.

[0041] In one embodiment of the present invention, the leveling agent is A-80 (arylphenol polyoxyethylene ether). The mass ratio of azo disperse orange dye to the leveling agent is 1:0.5~0.8. Specifically, 1:0.6 is optional.

[0042] In one embodiment of the present invention, the polyester-spandex blended fiber contains 80% polyester and 20% spandex.

[0043] In one embodiment of the present invention, the dye bath and the polyester-spandex blended fiber are dyed at a bath ratio of 1:25.

[0044] In one embodiment of the present invention, the specific dyeing process conditions are as follows: the temperature is increased by 2℃ / min to 130℃ and then kept at that temperature for 40min, then cooled to room temperature. The dyed fabric sample is washed several times with hot water and then dried in an oven at 60℃ to finally obtain a polyester-spandex blended dyed fabric sample.

[0045] The present invention provides a polyester-ammonia blended dyeing product based on the above method.

[0046] The present invention also provides the application of the above-mentioned polyester-spandex blended dyed products in clothing, medical pressure clothing, and household products.

[0047] Beneficial effects 1) The disperse blue dye provided by the present invention, in order to increase hydrophobicity and reduce the flowability of the dye in the hydrophobic region of spandex, uses a substituent containing a benzene ring or its derivative as the N-substituent of the coupling component to enhance the van der Waals force with spandex molecules. This type of disperse blue dye has high wash fastness, rubbing fastness and wet treatment fastness.

[0048] 2) The disperse blue dye provided by the present invention increases the volume and rigidity of the dye due to the presence of the N-substituted benzene ring structure, and its hydrophobicity is more compatible with the supramolecular structure of spandex, thus improving the overall fastness.

[0049] 3) The disperse blue dye provided by this invention, due to the effect of the benzene ring of the N-substituent, significantly expands the pH range for dyeing if the adjacent N-substituent is an easily hydrolyzed group such as an ester or cyano group, extending it from the original pH=4~8 to pH=4~12. The re-dyeing performance is greatly improved compared to acidic conditions lacking the N-benzene ring substituent, indicating that the N-benzene ring substituent has a protective effect on the adjacent N-cyano / ester groups due to steric hindrance. Therefore, this type of dye can easily achieve a one-bath process of "bleaching, scouring, and dyeing" or a one-bath process of "alkali reduction / dyeing," representing a typical practice of promoting industrial upgrading through technological innovation. The use of alkali-resistant dyes directly responds to the core demands of the current printing and dyeing industry for green, efficient, and high-quality development. Attached Figure Description

[0050] Figure 1 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 1.

[0051] Figure 2 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 2.

[0052] Figure 3 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 3.

[0053] Figure 4 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 4.

[0054] Figure 5 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 5.

[0055] Figure 6 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 6.

[0056] Figure 7 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 7.

[0057] Figure 8 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 8.

[0058] Figure 9 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 9.

[0059] Figure 10 The image shows the UV spectrophotometer detection spectrum of the product obtained in Example 10.

[0060] Figure 11 This is the 1H NMR spectrum of dye 1.

[0061] Figure 12 This is the 1H NMR spectrum of dye 2.

[0062] Figure 13 This is the 1H NMR spectrum of dye 3.

[0063] Figure 14 This is the 1H NMR spectrum of dye 4.

[0064] Figure 15 Fabric samples 1-10 were dyed with 10 dyes. Detailed Implementation

[0065] The source of raw materials involved in this invention: o-Chloro-4-nitroaniline, 2-chloro-6-cyano-4-nitroaniline, and 2,6-dicyano-4-nitroaniline were all purchased from Shanghai Maclean Biochemical Technology Co., Ltd. 93% sulfuric acid, 40% nitrosylsulfuric acid, 31% hydrochloric acid, sodium nitrite, urea, sulfamic acid, sodium bicarbonate, sodium acetate, sodium carbonate, acetic anhydride, sodium hydroxide, and acetone were all purchased from Sinopharm Chemical Reagent Co., Ltd. Pingpingjia O-25 was purchased from Jiangsu Haian Petrochemical Plant; Diphenylamine, N-cyanoethyl-m-toluidine, N-ethyl-m-toluidine, N-cyanoethyl aniline, and N-ethyl aniline were all purchased from Shanghai Maclean Biochemical Technology Co., Ltd., while 2-amino-5-nitrobenzisisothiazole and N-acetylacetylaniline were provided by Penglai Jiaxin Dyestuff Chemical Co., Ltd.

[0066] 4-chlorobenzyl chloride, 3-chloro-4-methylbenzyl chloride, 3-nitro-4-methylbenzyl chloride, (2-chloroethyl)benzene, and 1-(4-methylphenyl)-2-chloroethane were all purchased from Shanghai Maclean Biochemical Technology Co., Ltd. MF, sodium lignosulfonate, leveling agent, and several azo disperse dyes with similar structures, used as comparative examples, were all provided by Penglai Jiaxin Dyestuff Chemical Co., Ltd.

[0067] The synthesis method follows the following synthesis route: Example 1 Preparation of dye 1

[0068] (1) Add 40g of water and 10g of N-cyanoethyl-m-acetaminoaniline to a four-necked flask, start stirring, add 9.5g of 4-methyl-3-chlorobenzyl chloride and 5.5g of sodium bicarbonate, stir for 10min, then slowly raise the temperature to 65℃ and keep it at this temperature for 2h, then raise the temperature to 85℃ and keep it at this temperature for 8h. TLC detection showed that the raw material spot of N-cyanoethyl-m-acetaminoaniline disappeared. Cool to room temperature, let the separatory funnel stand and separate into layers, and release the lower layer material, about 16g, which is the azo component of dye 1. HPLC detection showed 94.5%.

[0069] (2) Add 17.5 ml of water, 6.9 g of 2-chloro-4-nitroaniline and 11.8 g of 31% hydrochloric acid to a four-necked flask, stir for 10 min, cool down to below 3°C, and start adding 11.05 g of pre-prepared 30% sodium nitrite solution dropwise. Control the dropwise addition time to more than 1 h. After the dropwise addition is completed, keep it at below 3°C for 2 h to obtain diazo solution, which is ready for use.

[0070] (3) Add 200g of water, 16g of the azo component of dye 1, 6g of 93% sulfuric acid, 0.6g of urea, and 0.8g of acetone 0.25 to a four-necked flask. Start stirring and cool to below 5°C. Begin adding 47.25g of diazonium solution dropwise, ensuring the temperature does not exceed 10°C during the addition. After the addition is complete, maintain the temperature at this level for at least 6 hours. Once the endpoint is reached, raise the temperature to 85°C and maintain it for 2 hours. Perform hot filtration, wash the filter cake with hot water until the wash water is colorless, and dry the resulting wet product in a 100°C oven to obtain a dark blue powdery solid dye 1 (17.8g).

[0071] Example 2 Preparation of dye 2

[0072] (1) 40g of water, 10g of N-acetylacetyl-m-acetaminoaniline, 8.4g of 4-methyl-3-chlorobenzyl chloride, and 5.4g of sodium bicarbonate were put into a four-necked flask, stirred, heated to 80℃ and kept at that temperature for 1h, then heated to reflux and kept at that temperature for 14h. After the reaction was completed, the mixture was poured into a separatory funnel and allowed to stand to separate into layers. The lower water layer was removed, and 100g of water was added again. The mixture was shaken for a while and allowed to stand again. The lower water layer was removed, and about 16.5g of a yellowish-brown oily intermediate was obtained, which is the coupling component of dye 2. The HPLC detection showed that the chromium content was 93%.

[0073] (2) Add 16 ml of water, 7.6 g of 2-cyano-4-nitro-6-chloroaniline and 11.4 g of 31% hydrochloric acid to a four-necked flask. After stirring for 10 min, cool the flask to below 0°C and start adding 8.9 g of pre-prepared 30% sodium nitrite solution. The addition time should be controlled to be more than 1 h. After the addition is completed, keep the flask at below 0°C for 2 h before use.

[0074] (3) Add 200g of water, 16.5g of the azo component of dye 2, 8g of 93% sulfuric acid, 0.8g of urea, and 1.0g of acetone 0-25 to a four-necked flask. Start stirring and cool to below 5°C. Begin adding 44g of diazonium solution dropwise, ensuring the temperature does not exceed 10°C during the addition. After the addition is complete, maintain the temperature at this level for at least 6 hours. Once the endpoint is reached, raise the temperature to 70°C and maintain it for 2 hours. Perform hot filtration, wash the filter cake with hot water until the wash water is colorless, and dry the resulting wet product in a 100°C oven to obtain 20.1g of a blue-black powdery solid.

[0075] Example 3 Preparation of dye 3

[0076] (1) 60g of water, 10g of N-ethyl-m-acetaminoaniline, 11.45g of 4-methyl-3-nitrobenzyl chloride and 7g of sodium bicarbonate were put into a four-necked flask, stirred, heated to 85℃ and kept at that temperature for 3h, then heated to 95℃ and kept at that temperature for 8h. The reaction was detected by TLC. The reaction endpoint was the disappearance of the starting material spot of N-ethyl-m-acetaminoaniline. After the reaction was completed, the mixture was poured into a separatory funnel and allowed to stand for separation. The lower water layer was discharged, and 100g of water was added again. The mixture was shaken for a while and allowed to stand again. The lower water layer was discharged, and 16.5g of brown oily substance was obtained, which is the coupling component of dye 3. The HPLC detection showed 94.5%.

[0077] (2) Put 18 ml of water, 10 g of 2,6-dicyano-4-nitroaniline and 6.3 g of 31% hydrochloric acid into a four-necked flask, stir for 10 min, cool down to below 0℃, and start adding 14.5 g of pre-prepared 30% sodium nitrite solution dropwise. The dropwise addition time should be controlled to be more than 1 h. After the dropwise addition is completed, keep it at below 0℃ for 2 h before use.

[0078] (3) Add 200g of water, 16.5g of the azo component of dye 3, 6g of 93% sulfuric acid, 0.5g of urea, and 1.0g of acetone 0-25 to a four-necked flask. Start stirring and cool to below 5°C. Begin adding 48.8g of diazonium solution dropwise, ensuring the temperature does not exceed 10°C during the addition. After the addition is complete, maintain the temperature at this level for at least 6 hours. Once the endpoint is reached, raise the temperature to 65°C and maintain it for 2 hours. Perform hot filtration, wash the filter cake with hot water until the wash water is colorless, and dry the resulting wet product in a 100°C oven to obtain 24.6g of a dark blue powdery solid.

[0079] Example 4 Preparation of dye 4

[0080] (1) 60g of water, 10g of N-cyanoethyl-m-acetaminoaniline, 10.5g of 4-methyl-3-nitrobenzyl chloride and 6.2g of sodium bicarbonate were put into a four-necked flask, stirred, heated to 65℃ and kept at that temperature for 2h, heated to 80℃ and kept at that temperature for 2h, and then heated to reflux and kept at that temperature for 12h. The reaction was detected by TLC, and the reaction endpoint was the disappearance of the starting material spot of N-cyanoethyl-m-acetaminoaniline. The reaction was then completed, poured into a separatory funnel and allowed to stand for separation. The lower water layer was discharged, and 100g of water was added again. The mixture was shaken for a while and allowed to stand again. The lower water layer was then discharged, and 15.25g of yellowish-brown oily substance was obtained, which was the coupling component of dye 4. The HPLC detection showed 93.4%.

[0081] (2) Put 20ml of water, 8g of 2-chloro-4-nitroaniline and 13.76g of 31% hydrochloric acid into a four-necked flask, stir for 10min, cool down to below 3℃, and start adding 11.7g of pre-prepared 30% sodium nitrite solution. The addition time should be controlled to be more than 1h. After the addition is completed, keep it at below 3℃ for 2h before use.

[0082] (3) Add 200g of water, 15.25g of the azo component of dye 4, 8g of 93% sulfuric acid, 0.8g of urea, and 1.0g of 25g of acetone to a four-necked flask. Start stirring and cool to below 5°C. Begin adding 53.5g of diazonium solution dropwise, ensuring the temperature does not exceed 10°C during the addition. After the addition is complete, maintain the temperature at this level for at least 6 hours. Once the endpoint is reached, raise the temperature to 70°C and maintain it for 2 hours. Perform hot filtration, wash the filter cake with hot water until the wash water is colorless, and dry the resulting wet product in a 100°C oven to obtain 21g of blue powdery solid.

[0083] Example 5 Preparation of dye 5

[0084] Following Example 4, 10.5 g of 4-methyl-3-nitrobenzyl chloride was replaced with 8 g of 4-(2-chloroethyl)toluene, while keeping the other conditions unchanged. Finally, 19.86 g of a dark blue powdery solid was obtained.

[0085] Example 6 Preparation of dye 6

[0086] Add 10g of 2-amino-5-nitrobenzisothiazol and 60g of sulfuric acid to a four-necked flask, stir and mix until the 2-amino-5-nitrobenzisothiazol is completely dissolved. Then, begin cooling to below 2°C and start adding 19.5g of 40% nitrosylsulfuric acid dropwise. The addition should take at least 1 hour. After the addition is complete, maintain the temperature below 2°C for 1 hour before use.

[0087] Add 60g of water and 9.5g of diphenylamine to a four-necked flask, stir and mix for 10 minutes, then add 0.5g of aminosulfonic acid and 0.8g of 0.25g of sulfadiazine. Start cooling to below 5°C, then add 89.5g of diazonium solution dropwise, ensuring the temperature does not exceed 5°C during the addition. After the addition is complete, maintain this temperature for at least 6 hours. Once the endpoint is reached, raise the temperature to 90°C and maintain it for 2 hours. Perform hot filtration, washing the filter cake with hot water until the wash water is colorless. Dry the resulting wet product in a 100°C oven to obtain 17.7g of a blue powdery solid.

[0088] Example 7 Preparation of dye 7

[0089] (1) 45g of water, 10g of N-cyanoethyl aniline, 11.1g of 4-methylbenzyl chloride and 8.6g of sodium bicarbonate were put into a four-necked flask, stirred, and heated to 70℃ at a rate of 5℃ / 10min and kept at that temperature for 4h. Then the temperature was raised to reflux and kept at that temperature for 12h. The reaction was detected by TLC. The reaction was considered to have ended when the starting material spot of N-cyanoethyl aniline disappeared. The mixture was poured into a separatory funnel and allowed to stand for separation. The lower water layer was removed, and 100g of water was added again. The mixture was shaken for a while and allowed to stand again. The lower water layer was removed, and 15.4g of brown oily substance was obtained, which was the coupling component of dye 7. The HPLC detection showed that the saturation was 94.2%.

[0090] (2) Add 12.68g of 2-amino-5-nitrobenzisothiazole and 75g of sulfuric acid to a four-necked flask, start stirring and mixing until the 2-amino-5-nitrobenzisothiazole is completely dissolved, then start cooling to below 0℃, and begin adding 22.7g of 40% nitrosyl sulfuric acid dropwise. The dropwise addition time should be controlled to be more than 1 hour. After the dropwise addition is completed, keep it at below 0℃ for 1 hour before use.

[0091] (3) Add 200g of water, 15.4g of the azo component of dye 7, 6g of 93% sulfuric acid, 0.8g of aminosulfonic acid, and 0.6g of 25g of sulfadiazine to a four-necked flask. Start stirring and cool to below 5°C. Begin adding 110.38g of diazonium solution dropwise, ensuring the temperature does not exceed 10°C during the addition. After the addition is complete, maintain the temperature at this level for at least 6 hours. Once the endpoint is reached, raise the temperature to 70°C and maintain it for 2 hours. Perform hot filtration, wash the filter cake with hot water until the wash water is colorless, and dry the resulting wet product in a 100°C oven to obtain 26.5g of blue powdery solid.

[0092] Example 8 Preparation of dye 8

[0093] According to Example 7, 10g of N-cyanoethylaniline was replaced with 8.3g of N-ethylaniline, and 11.1g of 4-methylbenzyl chloride was replaced with 13.8g of 4-methyl-3-chlorobenzyl chloride, while keeping the other conditions unchanged, and finally 24.2g of the dry product of dye 8 was obtained.

[0094] Example 9 Preparation of dye 9

[0095] According to Example 7, 10g of N-cyanoethyl aniline was replaced with 9.25g of N-ethyl-m-toluidine, and 11.1g of 4-methylbenzyl chloride was replaced with 14.65g of 4-methyl-3-nitrobenzyl chloride. At the same time, the condensation process was changed from holding at 70°C for 4 hours and refluxed for 12 hours to holding at 65°C for 2 hours, and then heated to 90°C for 14 hours. All other conditions remained unchanged, and finally 25.8g of dry dye 9 was obtained.

[0096] Example 10 Preparation of dye 10

[0097] According to Example 9, 14.65g of 4-methyl-3-nitrobenzyl chloride was replaced with 12.2g of 4-(2-chloroethyl)toluene. At the same time, the condensation process was changed from 65°C for 2 hours and 90°C for 14 hours to 60°C for 1 hour, 70°C for 1 hour and 85°C for 8 hours, with the other conditions remaining unchanged. Finally, 23.9g of the dry product of dye 10 was obtained.

[0098] Application Example 1 Dye bath preparation: Grind 1g of dye 1, 1g of MF, 0.5g of sodium lignosulfonate, and 1g of water in a mortar until the particle size is approximately 500nm. Then, prepare a 100ml dye bath using deionized water. Adjust the pH of the solution to 10 using a 0.4g / L sodium hydroxide solution. After adjustment, add a few drops of leveling agent A-80 (arylphenol polyoxyethylene ether) (approximately 0.3g) using a disposable dropper. After shaking evenly, use a 5ml disposable dropper to draw 5ml of dye 1 solution and prepare a 25ml dye bath using deionized water. Then, dye the polyester / spandex blended fiber (80% polyester, 20% spandex) at a liquor ratio of 1:25.

[0099] Dyeing process: The temperature is increased by 2℃ / min to 130℃ and then kept at that temperature for 40 minutes. The temperature is then reduced to room temperature. The dyed fabric sample is washed several times with hot water and then dried in a 60℃ oven for testing.

[0100] Application Examples 2-10 Following the procedure in Application Example 1, dye 1 was replaced with dyes 2 through 10 respectively, while keeping other conditions unchanged. Finally, dyed fabric samples 2 through 10 were obtained, as shown in [reference needed]. Figure 15 .

[0101] Test Example 1 Weigh 2g of each of dyes 1 to 10, dissolve them in 25ml of acetone at 45℃, allow them to cool naturally to below 20℃, then cool them in an ice bath to below 10℃ to precipitate most of the crystals. Filter, wash with ethanol, and dry to obtain pure dyes.

[0102] UV testing: Acetone was used to dissolve the sample at a uniform concentration, and the maximum absorption wavelength λ was measured using a UV-Vis spectrophotometer. max And the molar extinction coefficient ε, see Figures 1-10 The results are summarized in Table 1 below: Table 1

[0103] Hydrogen spectroscopy test: Pure samples of dyes 1 to 4 were dissolved in DMSO and subjected to hydrogen spectroscopy using a 300 MHz nuclear magnetic resonance spectrometer. Figures 11-14 This is the hydrogen spectrum.

[0104] Test Example 2 The fabric samples dyed with dyes 1 to 10, and the dyeing rates measured according to the residual liquor method, are respectively assigned to fabric samples 1 to 10, as follows: Figure 15 As shown, the data obtained from the Data Color 600 colorimeter test are summarized in Table 2 below: Table 2

[0105] Test Example 3 The fabric samples obtained from Examples 1-10 were subjected to various fastness tests, and the test results are shown in Table 3 below: Table 3

[0106] Comparative Examples 1-5 Following the method described in the application example, a disperse blue dye with a similar structure and whose N,N-substituents in the azo component do not contain benzene ring structures was selected as a comparative example to dye polyester-spandex blended fabrics. The resulting dyed fabric samples underwent fastness testing, and the dye uptake rate was also tested using the residual liquor method. The comparative samples are shown in Table 4 below: Table 4

[0107] The color fastness and dye uptake test results of the control fabrics corresponding to dyes 1-5 in Comparative Examples 1-5 are shown in Table 5 below: Table 5

[0108] Comparative data show that conventional azo disperse dyes are easy to enter and exit spandex, resulting in poor binding force and therefore generally poor color fastness.

[0109] Comparative Example 6 According to the application examples, the dye bath was adjusted to pH conditions of 4.5, 6, 8, 10, and 12, respectively. Two dyes from Examples 1 and 2 were selected for testing, and two dyes from Comparative Examples 4 and 5 were selected as controls. These four dyes were used with a uniform dyeing process to dye polyester-spandex blended fabric samples. The dye uptake rate was tested using the residual liquor method, and the results are shown in Table 6 below: Table 6

[0110] The data in the table above show that Comparative Examples 4 and 5 are suitable for staining under acidic conditions. As the alkali concentration increases, the ester groups they contain tend to hydrolyze, thus reducing the staining rate.

[0111] According to the technical solution and corresponding test data provided by the present invention, the azo disperse blue dye containing N-benzene ring substituents provided by the present invention has outstanding and unique properties in dyeing polyester-ammonia blended fabrics, whether in terms of dyeing over a wide pH range, dyeing rate, or various fastness properties.

[0112] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A dyeing method for improving the color fastness of spandex based on disperse blue dye, wherein the structure of the disperse blue dye is shown in Formula I: Formula I in, M is R1 is -NHCOCH3 or -NHCOCH2CH3; or, M is R1 is -H, -CH3, -CH2CH3, -NHCOCH3, -NHCOCH2CH3; R a R b Each of the following is independently selected from -H, -Cl, -Br, -CN, and -NO2; R2 can be -H, -CH3, -CH2CH3, -CH2CH2CN, or -COCH2COCH3; R3 can be -H, -CH3, -CH2CH3, or -Cl; R4 represents -H, -Cl, and -NO2; n is 0, 1, or 2.

2. The staining method according to claim 1, characterized in that, M is specifically selected from: 。 3. The staining method according to claim 1, characterized in that, The disperse blue dye is specifically selected from: 、 、 、 、 、 、 、 、 、 。 4. The staining method according to any one of claims 1-3, characterized in that, The method includes: mixing and grinding azo disperse orange dye, MF, sodium lignosulfonate and water, then diluting with water to prepare an initial dye bath, adjusting the pH of the initial dye bath to 4.5-12, then adding a leveling agent to obtain the dye bath; finally, placing the polyester-spandex blended fiber in the obtained dye bath for dyeing.

5. The staining method according to claim 4, characterized in that, The mass ratio of azo disperse orange dye to MF is 1:0.5~1.

2.

6. The staining method according to claim 4, characterized in that, The mass ratio of azo disperse orange dye to sodium lignosulfonate is 1:0.5~0.

8.

7. The staining method according to claim 4, characterized in that, The leveling agent is arylphenol polyoxyethylene ether, and the mass ratio of azo disperse orange dye to leveling agent is 1:0.5~0.

8.

8. The staining method according to claim 4, characterized in that, The dye bath and polyester / spandex blended fibers were dyed at a bath ratio of 1:

25. The specific dyeing process conditions were as follows: the temperature was increased by 2℃ / min to 130℃ and then kept at that temperature for 40 minutes. The temperature was then reduced to room temperature. The dyed fabric sample was washed several times with hot water and then dried in an oven at 60℃ to finally obtain the polyester / spandex blended dyed fabric sample.

9. A polyester-ammonia blended dyed product prepared by the method according to any one of claims 1-8.

10. The application of the polyester-spandex blended dyed product of claim 9 in clothing, medical pressure garments, and household goods.

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