Printing and dyeing method of high-elasticity environment-friendly cloth

Abstract

The present application relates to the field of textile dyeing and finishing technology, and provides a printing and dyeing method of high-elasticity environment-friendly cloth, which solves the problems of low dyeing rate, more floating color, and difficult effective deep treatment and reuse of printing and dyeing wastewater in the existing printing and dyeing technology; the method comprises the steps of dyeing, washing and wastewater collection and treatment; when dyeing, the high-elasticity environment-friendly cloth is immersed into a dyeing tank, the bottom of the dyeing tank is provided with a first micro-nano bubble distributor and is communicated with a generator, and the upper part is provided with a guide roller group for squeezing residual liquid; when washing, the high-elasticity environment-friendly cloth is moved to a washing tank, the bottom of the washing tank is provided with a second micro-nano bubble distributor and is communicated with a generator; the wastewater is collected into a wastewater pool and then is sent into a photocatalytic reaction pool, the photocatalytic reaction pool is provided with a transparent upper cover and a metal halide lamp, the bottom distributor is provided with micro-nano bubbles, a graphite phase carbon nitride catalyst is added and stirring is conducted, after photocatalytic degradation, the wastewater is sent into a sedimentation tank for standing, and the supernatant is sent into a clean water collection area for reuse.

Description

Technical Field

[0001] This invention relates to the field of textile dyeing and finishing technology, and in particular to a dyeing and printing method for high-elasticity environmentally friendly fabric. Background Technology

[0002] In the textile printing and dyeing industry, traditional dyeing and washing processes generally suffer from high energy consumption, low efficiency, and environmental pollution. The dyeing stage typically employs conventional stirring or simple aeration, resulting in uneven dye dispersion in the dye liquor and insufficient penetration into the fibers. This leads to low dye uptake and excessive residual dye, increasing dye consumption and production costs while also causing persistently high levels of colored pollutants in the wastewater. The washing process relies heavily on water flow, which is insufficient to effectively remove unfixed dye and impurities from the fiber surface, resulting in poor wash fastness and impacting product quality.

[0003] Meanwhile, dyeing and printing wastewater has a complex composition, containing residual dyes, surfactants, auxiliaries, and various organic pollutants. Existing wastewater treatment technologies often employ biochemical degradation or single chemical oxidation methods, which suffer from low degradation efficiency, long treatment times, and high reagent consumption, making it difficult to achieve effective water resource reuse and hindering the industry's green development.

[0004] Chinese Patent Publication No. CN115522343A discloses a high-efficiency dyeing and printing process for fabrics, including the following steps: S1: The greige fabric is first turned over and sewn, then treated with a treatment solution, and after the treatment solution is completed, it is pre-shaped by multiple water washes; S2: The pre-shaped fabric is unloaded by an unloading mechanism, and then the fabric surface is activated by a plasma surface treatment device. After activation, the fabric is immersed in the dye bath for multiple back-and-forth dyeing; S3: The dyed fabric is heated and dried by a drying and setting device, and then rolled up; S4: The rolled-up fabric is washed multiple times in a counter-current manner, and then dried and set to obtain the final product. This dyeing and printing process solves the problems of easy fading and serious color difference between the upper and lower layers of the fabric after dyeing. However, this process still has the problems of low dyeing rate and a lot of residual floating dye. The counter-current washing step relies on water flow rinsing, which is difficult to effectively remove unfixed dye and various impurities on the fiber surface, and the wash fastness is not good.

[0005] Chinese Patent Publication No. CN106930022A discloses a plasma micro-nano bubble dyeing system. The system includes a plasma processor, a plasma exhaust gas extraction device, a dye liquor output device, a dye liquor input device, and a microbubble generator. The plasma exhaust gas extraction device includes an extraction pipe and an extraction pump mounted on the extraction pipe. One end of the extraction pipe is connected to the plasma processor, and the other end is connected to the microbubble generator. The dye liquor output device includes an output pipe and an output pump mounted on the output pipe. The dye liquor input device includes an input pipe and an input pump mounted on the input pipe. Both ends of the output and input pipes are connected to the microbubble generator and the dyeing tank, respectively. The plasma exhaust gas is reacted with the dye water by the microbubble water generator to form a micro-nano bubble dye liquor rich in plasma exhaust gas. This system can be used for dyeing fabrics and yarns. However, this system is designed for salt-free dyeing, limiting its applicability. It is difficult to adapt to high-concentration wastewater treatment and lacks the capability for deep wastewater treatment and reuse. Summary of the Invention

[0006] Therefore, in view of the above problems, the present invention provides a dyeing method for high-elasticity environmentally friendly fabric, which solves the problems of low dye uptake rate, excessive floating color, and difficulty in effectively treating and reusing dyeing wastewater in existing dyeing technologies.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A dyeing method for high-elasticity, environmentally friendly fabric includes the following steps:

[0009] S1. Dyeing: The high-elasticity environmentally friendly fabric is immersed in a dyeing tank containing an aqueous dye. A first micro-nano bubble distributor is located at the bottom of the dyeing tank and is connected to a micro-nano bubble generator. A fabric guide roller group is located at the top of the dyeing tank to guide the high-elasticity environmentally friendly fabric through the aqueous dye at a uniform speed and to squeeze out excess dye. Residual dye is collected in a waste liquid tank. The fabric guide roller group includes a first guide roller, a second guide roller, an immersion roller group, and an extrusion roller group. Micro-nano bubbles are introduced into the aqueous dye. Dyeing is performed in the dyeing tank at a temperature of 60℃-95℃ and a liquor ratio of 1:8-15 for 30-50 minutes.

[0010] S2. Washing: After dyeing, the high-elastic environmentally friendly fabric is transferred to the washing tank via the third guide roller. The bottom of the washing tank is equipped with a second micro-nano bubble distributor, which is connected to the micro-nano bubble generator. The washing process is carried out in the washing tank at a temperature of 40℃-60℃ for 10min-20min.

[0011] S3. Wastewater Collection and Treatment: The overflow outlets and bottom drains of the dyeing tank, waste liquid tank, and washing tank are connected to the wastewater collection tank via pipes. The effluent from the wastewater collection tank is sent to the photocatalytic reaction tank. The photocatalytic reaction tank is equipped with a transparent top cover, and a metal halide lamp is installed outside the transparent top cover as a light source. A third micro-nano bubble distributor is installed at the bottom of the photocatalytic reaction tank, and the third micro-nano bubble distributor is connected to a micro-nano bubble generator. A photocatalyst, which is powdered graphitic carbon nitride, is added to the photocatalytic reaction tank. The stirring device in the photocatalytic reaction tank is turned on to keep the photocatalyst in a suspended state. At the same time, micro-nano bubbles are introduced into the bottom of the tank to enhance mass transfer and carry out the photocatalytic degradation reaction. After the reaction is completed, the degradation water is sent to the sedimentation tank and left to stand for 30-60 minutes to allow the photocatalyst powder to settle completely. The supernatant enters the clear water collection area.

[0012] After washing, the high-elasticity environmentally friendly fabric undergoes finishing processes to obtain the finished high-elasticity environmentally friendly fabric.

[0013] Furthermore, the water-based dye comprises the following components by weight: 5-8 parts dye, 1-3 parts functional auxiliaries, 0.5-1.5 parts polyoxyethylene ether dispersant, 0.2-0.6 parts sodium citrate-disodium hydrogen phosphate buffer, 0.05-0.15 parts defoamer, and 80-95 parts deionized water.

[0014] Furthermore, the preparation process of the powdered graphitic carbon nitride is as follows: melamine and alkali lignin are mixed at a mass ratio of 100:(2-8), stirred in an aqueous phase, dried, and then thermally polymerized at 520℃-550℃ for 3-4 hours to obtain bulk graphitic carbon nitride; the bulk graphitic carbon nitride is added to water to form a suspension with a concentration of 0.5%-2%, and ultrasonically treated at a power of 200W-400W and a frequency of 28kHz-40kHz for 1-2 hours, and then spray-dried to obtain the powdered graphitic carbon nitride photocatalyst.

[0015] Furthermore, the photocatalyst slurry that settles at the bottom of the sedimentation tank is periodically removed, and after solid-liquid separation, washing, and drying, it is reused in the photocatalytic reaction tank, and can be reused at least 5 times.

[0016] Furthermore, the post-processing includes dehydration, pre-shaping, drying, inspection, and rolling.

[0017] Furthermore, the high-elasticity environmentally friendly fabric is a fabric containing spandex, elastic polyester, polylactic acid elastic fiber or bio-based elastic fiber.

[0018] Furthermore, the preparation process of the functional additive is as follows:

[0019] a. Dissolve chitosan with a molecular weight of 100,000-300,000 in water to prepare an aqueous solution with a concentration of 2%-4%. Then add lactic acid to adjust the pH value to 4.0-5.0. Stir the reaction at a temperature of 60℃-90℃ for 3-6 hours to obtain deacetylated modified chitosan.

[0020] b. Using a carbon chain length of C 12 -C 18 Using saturated fatty acids and propylene glycol as raw materials, the saturated fatty acids and propylene glycol were added to a reaction vessel at a molar ratio of 1:1.2-2, and p-toluenesulfonic acid was added as an esterification catalyst. The amount of the esterification catalyst added was 1%-3% of the mass of the saturated fatty acids. The esterification reaction was carried out at a temperature of 130℃-150℃ for 4-8 hours. After the reaction was completed, the temperature was lowered to room temperature, the esterification catalyst was neutralized with sodium bicarbonate solution, washed with water until neutral, excess propylene glycol was removed by vacuum distillation, and the mixture was dried to obtain a fatty acid ester with an HLB value of 8-12.

[0021] c. Prepare an aqueous solution of the deacetylated modified chitosan with a mass concentration of 1%-2% to obtain a modified chitosan solution; heat the modified chitosan solution to 30℃-50℃, and under the condition of stirring speed of 200rpm-400rpm, slowly add molten fatty acid ester to the modified chitosan solution at a mass ratio of deacetylated modified chitosan to fatty acid ester of 1:0.5-1.5, and continue stirring for 30min-60min until the mixture is uniform to obtain a functional additive.

[0022] The functional auxiliaries added to the aqueous dye are a complex of modified chitosan and fatty acid esters. Modified chitosan has better water solubility and contains a large number of amino and hydroxyl groups, which can form hydrogen bonds with fatty acid esters. A carbon chain length of C is selected. 12 -C 18 Saturated fatty acids are esterified with propylene glycol to synthesize fatty acid esters with a hydrophilic-hydrophobic balance.

[0023] The surface of the micro-nano bubbles is negatively charged, while the functional additives are positively charged due to the amino groups present in the modified chitosan. Therefore, the functional additives are adsorbed on the bubble surface. At the same time, the functional additives interact with the dye molecules through hydrophobic fatty acid esters, and with the help of the floating and flowing of the bubbles, the dye is more evenly transported to the fiber gaps and interior of the high-elasticity environmentally friendly fabric.

[0024] By adopting the aforementioned technical solution, the beneficial effects of the present invention are as follows:

[0025] 1. A first micro-nano bubble distributor is installed at the bottom of the dyeing tank, and a second micro-nano bubble distributor is installed at the bottom of the washing tank. Both are connected to the same micro-nano bubble generator, which can introduce micro-nano bubbles into the dyeing solution and the washing solution. On the one hand, the micro-nano bubbles can promote the penetration of dye molecules into the fiber interior and reduce floating color; on the other hand, during washing, the mechanical flushing effect of bubble rupture can accelerate the removal of unfixed dye and impurities on the fiber surface.

[0026] 2. The functional auxiliaries added to the water-based dyes are composed of modified chitosan and fatty acid esters, and have an amphiphilic structure with both hydrophilic and hydrophobic properties. These functional auxiliaries can be adsorbed on the surface of micro-nano bubbles through electrostatic interaction, and float to the fiber surface with the micro-nano bubbles, promoting uniform adsorption of the dye.

[0027] 3. Wastewater from the dyeing tank, waste liquid tank, and washing tank is collected in a collection tank and then sent to a photocatalytic reaction tank. Photocatalytic degradation occurs through a graphite-phase carbon nitride photocatalyst. Combined with enhanced mass transfer via bubbling from a third micro / nano bubble distributor at the bottom of the tank, residual dyes and organic pollutants in the wastewater can be effectively decomposed. After settling in a sedimentation tank, the supernatant can be reused in the dyeing tank or washing tank, achieving water resource recycling. The settled photocatalyst slurry can be reused after solid-liquid separation, washing, and drying, significantly reducing wastewater treatment costs.

[0028] 4. This technical solution enhances dyeing and washing through micro-nano bubbles and combines photocatalytic closed-loop treatment of wastewater to achieve efficient and clean production. Attached Figure Description

[0029] Figure 1 This is a process flow diagram in an embodiment of the present invention;

[0030] The following are the labels in the diagram: 1. Dyeing tank; 2. First micro / nano bubble distributor; 3. Micro / nano bubble generator; 4. Fabric guide roller group; 5. Waste liquid tank; 41. First guide roller; 42. Second guide roller; 43. Immersion roller group; 44. Extrusion roller group; 6. Third guide roller; 7. Washing tank; 8. Second micro / nano bubble distributor; 9. Wastewater collection tank; 10. Photocatalytic reaction tank; 11. Transparent top cover; 12. Third micro / nano bubble distributor; 13. Stirring device; 14. Sedimentation tank. Detailed Implementation

[0031] Example 1

[0032] refer to Figure 1 A dyeing method for high-elasticity, environmentally friendly fabric includes the following steps:

[0033] S1, staining

[0034] High-elasticity environmentally friendly fabric is immersed in dyeing tank 1, which contains water-based dye. A first micro-nano bubble distributor 2 is located at the bottom of dyeing tank 1 and is connected to a micro-nano bubble generator 3. A fabric guide roller group 4 is located at the top of dyeing tank 1 to guide the high-elasticity environmentally friendly fabric through the water-based dye at a uniform speed and to squeeze out excess water-based dye. Residual dye is collected in a waste liquid tank 5. The fabric guide roller group 4 includes a first guide roller 41, a second guide roller 42, an immersion roller group 43, and an extrusion roller group 44. Micro-nano bubbles are introduced into the water-based dye, and dyeing is performed in dyeing tank 1 at a temperature of 60℃ and a liquor ratio of 1:8 for 30 minutes.

[0035] S1-1, The high-elasticity environmentally friendly fabric is a fabric containing spandex, elastic polyester, polylactic acid elastic fiber or bio-based elastic fiber;

[0036] S1-2, The water-based dye comprises the following components by weight: 5 parts dye, 1 part functional auxiliaries, 0.5 parts polyoxyethylene ether dispersant, 0.2 parts sodium citrate-disodium hydrogen phosphate buffer, 0.05 parts defoamer, and 95 parts deionized water.

[0037] S1-3, The preparation process of the functional additive is as follows:

[0038] a. Chitosan with a molecular weight of 200,000 was dissolved in water to prepare a 3% aqueous solution. Lactic acid was then added to adjust the pH to 4.5. The mixture was stirred and reacted at 60°C for 4 hours to obtain deacetylated modified chitosan.

[0039] b. Using a carbon chain length of C 12 Using saturated fatty acids and propylene glycol as raw materials, the saturated fatty acids and propylene glycol were added to a reaction vessel at a molar ratio of 1:1.5. p-Toluenesulfonic acid was added as an esterification catalyst, with the amount of catalyst added being 1% of the mass of the saturated fatty acids. The esterification reaction was carried out at 130°C for 4 hours. After the reaction, the temperature was lowered to room temperature, the esterification catalyst was neutralized with sodium bicarbonate solution, washed with water until neutral, excess propylene glycol was removed by vacuum distillation, and the mixture was dried to obtain a fatty acid ester with an HLB value of 10.

[0040] c. Prepare a 1.5% (w / w) aqueous solution of the deacetylated modified chitosan to obtain a modified chitosan solution; heat the modified chitosan solution to 45°C, and under the condition of stirring at 200 rpm, slowly add molten fatty acid ester to the modified chitosan solution at a mass ratio of 1:1 between deacetylated modified chitosan and fatty acid ester, and continue stirring for 60 min until the mixture is uniform to obtain a functional additive;

[0041] S2, Water Washing

[0042] After dyeing, the high-elastic environmentally friendly fabric is transferred to the washing tank 7 via the third guide roller 6. The bottom of the washing tank 7 is equipped with a second micro-nano bubble distributor 8, which is connected to the micro-nano bubble generator 3. The washing process is carried out in the washing tank 7 at a temperature of 40°C for 10 minutes.

[0043] S3. Wastewater Collection and Treatment

[0044] The overflow outlets and bottom drains of the dyeing tank 1, waste liquid tank 5, and washing tank 7 are respectively connected to the wastewater collection tank 9 through pipes; the effluent from the wastewater collection tank 9 is sent into the photocatalytic reaction tank 10, which is equipped with a transparent top cover 11. A metal halide lamp is installed outside the transparent top cover 11 as a light source. A third micro-nano bubble distributor 12 is installed at the bottom of the photocatalytic reaction tank, which is connected to the micro-nano bubble generator 3; a photocatalyst, which is powdered graphitic carbon nitride, is added into the photocatalytic reaction tank 10. The stirring device 13 in the photocatalytic reaction tank is turned on to keep the photocatalyst in a suspended state. At the same time, micro-nano bubbles are introduced into the bottom of the tank to enhance mass transfer and carry out the photocatalytic degradation reaction; after the reaction is completed, the degradation water is sent into the sedimentation tank 14 and left to stand in the sedimentation tank 14 for 30 minutes to allow the photocatalyst powder to settle completely. The supernatant enters the clear water collection area.

[0045] S3-1. The preparation process of the powdered graphitic carbon nitride is as follows: melamine and alkali lignin are mixed at a mass ratio of 100:2, stirred in an aqueous phase, dried, and then thermally polymerized at 520℃ for 3 hours to obtain bulk graphitic carbon nitride; the bulk graphitic carbon nitride is added to water to prepare a suspension with a concentration of 0.5%, ultrasonically treated at a power of 200W and a frequency of 28kHz for 1 hour, and then spray-dried to obtain the powdered graphitic carbon nitride photocatalyst;

[0046] S3-2. Periodically remove the photocatalyst slurry that has settled at the bottom of the sedimentation tank, and after solid-liquid separation, washing, and drying, put it back into the photocatalytic reaction tank for reuse, repeating the process 5 times.

[0047] S4, Dehydration

[0048] The washed high-elasticity environmentally friendly fabric is dehydrated using a centrifugal dehydrator to control the fabric surface moisture content to 30%.

[0049] S5, Pre-order type

[0050] Pre-forming is carried out in the tenter frame at a temperature of 150℃ and a speed of 15m / min.

[0051] S6, Drying

[0052] Dry the fabric in a hot air circulating drying oven until the surface moisture content is 5%;

[0053] S7. Inspection and Packaging

[0054] The finished fabric is inspected for appearance and physical properties. If it passes the inspection, it is wound into rolls to obtain a high-elasticity environmentally friendly finished fabric.

[0055] Example 2

[0056] The difference from Example 1 is as follows:

[0057] The water-based dye comprises the following components by weight: 6 parts dye, 2 parts functional auxiliaries, 1 part polyoxyethylene ether dispersant, 0.4 parts sodium citrate-disodium hydrogen phosphate buffer, 0.1 parts defoamer, and 90 parts deionized water.

[0058] The preparation process of the powdered graphitic carbon nitride is as follows: melamine and alkali lignin are mixed at a mass ratio of 100:5, stirred in an aqueous phase, dried, and then thermally polymerized at 530℃ for 3.5h to obtain bulk graphitic carbon nitride; the bulk graphitic carbon nitride is added to water to prepare a suspension with a concentration of 1%, ultrasonically treated at a power of 300W and a frequency of 35kHz for 1.5h, and then spray-dried to obtain the powdered graphitic carbon nitride photocatalyst;

[0059] Micro-nano bubbles were introduced into the water-based dye, and the dyeing process was carried out in dyeing tank 1 at a temperature of 75℃ and a liquor ratio of 1:12 for 40 minutes.

[0060] After dyeing, the high-elastic environmentally friendly fabric is transferred to the washing tank 7 via the third guide roller 6. The bottom of the washing tank 7 is equipped with a second micro-nano bubble distributor 8, which is connected to the micro-nano bubble generator 3. The washing process is carried out in the washing tank 7 at a temperature of 50°C for 15 minutes.

[0061] Other technical solutions are the same as in Example 1.

[0062] Example 3

[0063] The difference from Example 1 is as follows:

[0064] The water-based dye comprises the following components by weight: 8 parts dye, 3 parts functional auxiliaries, 1.5 parts polyoxyethylene ether dispersant, 0.6 parts sodium citrate-disodium hydrogen phosphate buffer, 0.15 parts defoamer, and 80 parts deionized water.

[0065] The preparation process of the powdered graphitic carbon nitride is as follows: melamine and alkali lignin are mixed at a mass ratio of 100:8, stirred in an aqueous phase, dried, and then thermally polymerized at 550℃ for 4 hours to obtain bulk graphitic carbon nitride; the bulk graphitic carbon nitride is added to water to prepare a suspension with a concentration of 2%, ultrasonically treated at a power of 400W and a frequency of 40kHz for 2 hours, and then spray-dried to obtain the powdered graphitic carbon nitride photocatalyst;

[0066] Micro-nano bubbles were introduced into the water-based dye, and the dyeing process was carried out in dyeing tank 1 at a temperature of 95℃ and a liquor ratio of 1:15 for 50 minutes.

[0067] After dyeing, the high-elastic environmentally friendly fabric is transferred to the washing tank 7 via the third guide roller 6. The bottom of the washing tank 7 is equipped with a second micro-nano bubble distributor 8, which is connected to the micro-nano bubble generator 3. The washing process is carried out in the washing tank 7 at a temperature of 60°C for 20 minutes.

[0068] Other technical solutions are the same as in Example 1.

[0069] Comparative Example 1

[0070] The difference from Example 1 is that no functional additives are added to the aqueous dye. All other technical solutions are the same as in Example 1.

[0071] Comparative Example 2

[0072] The difference from Example 2 is that a commercially available TiO2 powder photocatalyst is added to the photocatalytic reaction tank. All other technical aspects are the same as in Example 1.

[0073] Comparative Example 3

[0074] The difference from Example 3 is that the micro / nano bubble generator is not used. All other technical solutions are the same as in Example 1.

[0075] To test the staining rate, record the initial absorbance A0 of the aqueous dye. After the staining step is completed, measure the absorbance A of the remaining dye solution. t The dyeing rate is calculated according to formula (1):

[0076] (1)

[0077] The test for fastness to washing after the washing step shall be conducted in accordance with GB / T 3921-2008 Textiles - Tests for color fastness to soap washing.

[0078] The COD removal rate of the wastewater collection and treatment steps was tested. Wastewater samples were collected before and after the photocatalytic reaction and measured according to the "HJ828-2017 Determination of Chemical Oxygen Demand in Water - Dichromate Method".

[0079] The number of times the photocatalyst can be reused was tested. The photocatalyst prepared according to this technical solution was used for the first time to photocatalytically degrade wastewater and the COD removal rate was recorded as η1. After each reaction, the catalyst slurry was separated into solid and liquid, washed, dried, and put back into the reaction tank for the next degradation test. The COD removal rates for the second, third, fourth, and fifth degradation tests were recorded as η2, η3, η4, and η5, respectively.

[0080] The test results are shown in Table 1.

[0081] Table 1

[0082]

[0083] The test results in Table 1 show that: in terms of dyeing rate, Examples 1-3 are significantly higher than the comparative examples, with Example 3 reaching 95.3%, demonstrating good dyeing performance; in terms of wash fastness, Examples 1-3 can all achieve a high fastness level of 4-5; in terms of COD removal rate, the photocatalyst can still maintain a high COD removal effect during repeated use, with the COD removal rate of Examples 1-3 being higher than 80% in all five uses, indicating that the activity of the photocatalyst remains stable after multiple uses and has good reusability.

[0084] In Example 1, the addition of functional auxiliaries significantly improved the dyeing rate and provided excellent wash fastness. In Example 2, the use of the photocatalyst prepared by this technical solution enhanced the COD degradation capacity. In Example 3, the use of a micro-nano bubble generator effectively improved the performance of all test indicators.

[0085] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A printing and dyeing method for a high-elasticity, environmentally friendly fabric, characterized in that, Includes the following steps: S1. Dyeing: The high-elasticity environmentally friendly fabric is immersed in a dyeing tank containing an aqueous dye. A first micro-nano bubble distributor is located at the bottom of the dyeing tank and is connected to a micro-nano bubble generator. A fabric guide roller group is located at the top of the dyeing tank to guide the high-elasticity environmentally friendly fabric through the aqueous dye at a uniform speed and to squeeze out excess dye. Residual dye is collected in a waste liquid tank. The fabric guide roller group includes a first guide roller, a second guide roller, an immersion roller group, and an extrusion roller group. Micro-nano bubbles are introduced into the aqueous dye. Dyeing is performed in the dyeing tank at a temperature of 60℃-95℃ and a liquor ratio of 1:8-15 for 30-50 minutes. S2. Washing: After dyeing, the high-elastic environmentally friendly fabric is transferred to the washing tank via the third guide roller. The bottom of the washing tank is equipped with a second micro-nano bubble distributor, which is connected to the micro-nano bubble generator. The washing process is carried out in the washing tank at a temperature of 40℃-60℃ for 10min-20min. S3. Wastewater Collection and Treatment: The overflow outlets and bottom drains of the dyeing tank, waste liquid tank, and washing tank are connected to the wastewater collection tank via pipes. The effluent from the wastewater collection tank is sent to the photocatalytic reaction tank, which is equipped with a transparent top cover. A metal halide lamp is installed outside the transparent top cover as a light source. A third micro-nano bubble distributor is installed at the bottom of the photocatalytic reaction tank, which is connected to a micro-nano bubble generator. A photocatalyst, which is powdered graphitic carbon nitride, is added to the photocatalytic reaction tank. The stirring device in the photocatalytic reaction tank is turned on to keep the photocatalyst in a suspended state. At the same time, micro-nano bubbles are introduced into the bottom of the tank to enhance mass transfer and carry out the photocatalytic degradation reaction. After the reaction is completed, the degraded water is sent to the sedimentation tank and left to stand for 30-60 minutes to allow the photocatalyst powder to settle completely. The supernatant enters the clear water collection area. After washing, the high-elasticity environmentally friendly fabric is finished to obtain the high-elasticity environmentally friendly fabric product. The water-based dye comprises the following components by weight: 5-8 parts dye, 1-3 parts functional auxiliaries, 0.5-1.5 parts polyoxyethylene ether dispersant, 0.2-0.6 parts sodium citrate-disodium hydrogen phosphate buffer, 0.05-0.15 parts defoamer, and 80-95 parts deionized water. The preparation process of the functional additive is as follows: a. Dissolve chitosan with a molecular weight of 100,000-300,000 in water to prepare an aqueous solution with a concentration of 2%-4%. Then add lactic acid to adjust the pH value to 4.0-5.

0. Stir the reaction at a temperature of 60℃-90℃ for 3-6 hours to obtain deacetylated modified chitosan. b. Using saturated fatty acids with carbon chain lengths of C12-C18 and propylene glycol as raw materials, the saturated fatty acids and propylene glycol are added to a reaction vessel at a molar ratio of saturated fatty acids:propylene glycol = 1:1.2-2, and p-toluenesulfonic acid is added as an esterification catalyst. The amount of the esterification catalyst added is 1%-3% of the mass of the saturated fatty acids. The esterification reaction is carried out at a temperature of 130℃-150℃ for 4h-8h. After the reaction is completed, the temperature is cooled to room temperature, the esterification catalyst is neutralized with sodium bicarbonate solution, washed with water until neutral, excess propylene glycol is removed by vacuum distillation and dried to obtain fatty acid esters with an HLB value of 8-12. c. Prepare an aqueous solution of the deacetylated modified chitosan with a mass concentration of 1%-2% to obtain a modified chitosan solution; heat the modified chitosan solution to 30℃-50℃, and under the condition of stirring speed of 200rpm-400rpm, slowly add molten fatty acid ester to the modified chitosan solution at a mass ratio of deacetylated modified chitosan to fatty acid ester of 1:0.5-1.5, and continue stirring for 30min-60min until the mixture is uniform to obtain a functional additive.

2. The dyeing method for a high-elasticity environmentally friendly fabric according to claim 1, characterized in that, The preparation process of the powdered graphitic carbon nitride is as follows: melamine and alkali lignin are mixed at a mass ratio of 100:(2-8), stirred in an aqueous phase, dried, and then thermally polymerized at 520℃-550℃ for 3-4 hours to obtain bulk graphitic carbon nitride; the bulk graphitic carbon nitride is added to water to form a suspension with a concentration of 0.5%-2%, and ultrasonically treated at a power of 200W-400W and a frequency of 28kHz-40kHz for 1-2 hours, and then spray-dried to obtain the powdered graphitic carbon nitride photocatalyst.

3. The dyeing method for a high-elasticity environmentally friendly fabric according to claim 1, characterized in that: The photocatalyst slurry that settles at the bottom of the sedimentation tank is periodically removed, and after solid-liquid separation, washing, and drying, it is put back into the photocatalytic reaction tank for reuse. It can be reused at least 5 times.

4. The dyeing method for a high-elasticity environmentally friendly fabric according to claim 1, characterized in that: The post-processing includes dehydration, pre-shaping, drying, inspection, and rolling.

5. The dyeing method for a high-elasticity environmentally friendly fabric according to claim 1, characterized in that: The high-elasticity environmentally friendly fabric is a fabric containing spandex, elastic polyester, polylactic acid elastic fiber or bio-based elastic fiber.

Images