A dyeing process for improving color fastness of textile fabric

Abstract

This invention discloses a dyeing process for improving the color fastness of textile fabrics, specifically relating to the field of textile printing and dyeing technology. The method includes S1, activation pretreatment; S2, gradient temperature dyeing; S3, medium polarity control; S4, in-situ anchoring fixation; S5, gradient cooling fixation; S6, microbubble cleaning; and S7, low-temperature fixation. Specifically, the gradient temperature dyeing employs a three-stage gradient temperature curve; the medium polarity control adjusts the dye bath polarity in stages during the dyeing process; and the in-situ anchoring fixation simultaneously completes multi-point bonding between the dye and the fiber during the dyeing and heat preservation process. This invention can significantly reduce the fabric's floating dye rate, effectively inhibit the thermal migration of disperse dyes, improve the cross-staining properties of blended fabrics, and enhance the overall color fastness of the fabric.

Description

Technical Field

[0001] This invention relates to the field of textile printing and dyeing technology, and more specifically, to a dyeing process for improving the color fastness of textile fabrics. Background Technology

[0002] Color fastness is an important indicator for measuring the quality of textiles and directly affects the product's lifespan. Currently, the main technical approaches to improving the color fastness of textile fabrics include dye screening and modification, dyeing process optimization, and finishing with color-fixing agents.

[0003] However, existing technologies still have the following shortcomings: 1. During reactive dyeing, the fiber interior and surface contain a large amount of unfixed dye that fails to form covalent bonds with the fiber, including hydrolyzed dyes and unfixed dyes. The unfixed dye rate is particularly high when dyeing dark colors, resulting in poor wet fastness and rubbing fastness. 2. Disperse dyes commonly exhibit thermal migration. During high-temperature finishing, some dyes migrate from the fiber interior to the fiber surface, causing a decrease in color fastness and color variation. The darker the color and the higher the temperature, the more severe the thermal migration. 3. When dyeing blended fabrics such as cotton-nylon and polyester-cotton, there is a problem of color bleeding between the dyes used for different fiber components. In particular, reactive dyes have a more prominent staining effect on nylon, which affects the overall color fastness.

[0004] In addition, existing color-fixing technologies mostly employ a separate color-fixing process after dyeing, which has drawbacks such as long process flow and high energy consumption.

[0005] In view of the above situation, the present invention provides a dyeing process to improve the color fastness of textile fabrics. Summary of the Invention

[0006] To achieve the above objectives, the present invention provides the following technical solution: a dyeing process for improving the color fastness of textile fabrics, comprising the following steps: S1. Activation pretreatment: The fabric is pretreated by immersing it in a treatment solution containing biological enzymes and activators. S2. Gradient Temperature Dyeing: The pretreated fabric is placed in the dye bath and dyed according to a three-stage gradient temperature rise curve. The three-stage gradient temperature rise includes: The first stage involves heating from room temperature to 60–70°C at a rate of 0.5–1.0°C / min and holding at that temperature for 15–25 minutes. The second stage involves heating to 80–90°C at a rate of 0.8–1.2°C / min and holding at that temperature for 20–30 minutes. The third stage involves heating to 95–130°C at a rate of 0.3–0.6°C / min and holding at that temperature for 30–60 min. S3. Medium polarity control: During the gradient temperature dyeing process, add 2-5% organic solvent (by volume of the dye bath) to the dye bath after the first stage, add 5-15 g / L of neutral electrolyte after the second stage, and add 0.1-0.5 g / L of surfactant at the beginning of the third stage. S4. In-situ anchoring and fixing: 15-30 minutes after the start of the third stage of heat preservation, inject a multifunctional anchoring agent solution into the dye bath. The amount of anchoring agent is 5-15% of the weight of the dye, and the injection time is 10-20 minutes. S5. Gradient cooling and setting: After staining and heat preservation, cool down to 70-80℃ at a rate of 0.5-1.0℃ / min, then cool down to 40-50℃ at a rate of 2-3℃ / min, and finally cool down to room temperature at a rate of 0.1-0.3℃ / min. The room temperature is 25±5℃. S6. Microbubble cleaning: Micro-nano bubbles are used to clean the dyed fabric. The bubble diameter is 100nm~10μm, the cleaning temperature is 60~80℃, and the cleaning time is 10~20min. S7. Low-temperature setting: Heat setting is carried out at 130-150℃ for 30-60 seconds.

[0007] Preferably, in step S1, the bioenzyme is a polyamide hydrolase or a cellulase, and the dosage is 0.5 to 2.0 g / L.

[0008] Preferably, in step S1, the activator is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride.

[0009] Preferably, in step S3, the organic solvent is dimethyl sulfoxide.

[0010] Preferably, in step S4, the multifunctional anchoring agent is the reaction product of hyperbranched polyethyleneimine and epichlorohydrin, wherein the molecular weight of the hyperbranched polyethyleneimine is 10,000 to 30,000, and the molar ratio of the hyperbranched polyethyleneimine to epichlorohydrin is 1:40 to 200.

[0011] Preferably, the fabric is a blend of cotton, polyester, and nylon.

[0012] Preferably, in step S1, the pH of the treatment solution is 6.5 to 7.5, the treatment temperature is 45 to 55°C, the treatment time is 20 to 40 minutes, and the bath ratio is 1:10 to 1:15.

[0013] Preferably, in step S6, the surface of the micro-nano bubbles carries a negative charge.

[0014] Preferably, in step S6, the gas-liquid ratio is 1:5 to 1:10, and the pH is 7.0 to 8.5.

[0015] Preferably, in step S1, the treatment solution further contains a penetrant JFC, with a dosage of 0.5–1.5 g / L.

[0016] The technical effects and advantages of this invention are as follows: 1. This invention utilizes a three-stage gradient temperature dyeing process combined with in-situ anchoring and color fixing to create a concentration gradient distribution of dye molecules from the inside out within the fiber. Simultaneously, the anchoring agent forms a multi-site covalent-ionic composite bond network with the dye and fiber, firmly locking the dye within the fiber. Testing has verified that fabrics treated with this invention exhibit reduced floating color rate compared to conventional processes, while improving wash fastness and wet rubbing fastness. 2. This invention reduces the driving force for dye migration from the fiber interior to the surface under high temperature conditions by adjusting the dye bath polarity in stages during the dyeing process, thereby altering the chemical potential difference between dye molecules inside and on the fiber surface. After high-temperature dry heat treatment, the fabric treated with this invention exhibits a higher color fastness retention rate than that treated with conventional processes, indicating that this invention can effectively maintain the color fastness level of the fabric in high-temperature finishing processes. 3. This invention increases the effective reaction sites on the surface of the target fibers through activation pretreatment, enabling dyes to preferentially bind to the target fibers. Simultaneously, the polarity regulation of the medium reduces the dye's affinity for non-target fibers, minimizing dye transfer between different fiber components. Blended fabrics treated with this invention exhibit superior multi-fiber lining staining ratings compared to conventional processes, effectively improving the cross-staining problem in blended fabrics. Attached Figure Description

[0017] Figure 1 This is a flowchart of the overall method of the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Example 1:

[0019] This embodiment provides a dyeing process to improve the color fastness of textile fabrics, and the specific steps are as follows: S1, Activation Pretreatment A cotton-polyester blended fabric was used as the fabric to be dyed, with a cotton content of 65% and a polyester content of 35% by mass. A treatment solution was prepared by adding the following components: 1.0 g / L polyamide hydrolase, 0.5 g / L activator 1-ethyl-3,3-dimethylaminopropylcarbodiimide hydrochloride, and 1.0 g / L penetrant JFC. The pH of the treatment solution was adjusted to 7.0 using a pH buffer. The fabric was immersed in the treatment solution at a bath ratio of 1:12 and treated at 50°C for 30 minutes. After treatment, the fabric was removed, washed twice, and set aside for later use.

[0020] S2, gradient temperature staining The pre-treated fabric is placed in a dye bath, and reactive dyes and disperse dyes are added. The amount of reactive dyes is 3% of the fabric weight, and the amount of disperse dyes is 2% of the fabric weight. Dyeing is carried out according to a three-stage gradient temperature rise curve.

[0021] The first stage involves heating from room temperature (25℃) to 65℃ at a rate of 0.8℃ / min and holding at that temperature for 20 minutes.

[0022] The second stage involves heating to 85℃ at a rate of 1.0℃ / min and holding at that temperature for 25 minutes.

[0023] The third stage involves heating to 110℃ at a rate of 0.5℃ / min and holding at that temperature for 45 minutes.

[0024] S3, Medium Polarity Control During the gradient temperature staining process, dimethyl sulfoxide (DMSO) was added to the staining bath at 3% of the bath volume after the first stage; sodium sulfate (10 g / L) was added after the second stage; and surfactant (0.3 g / L) was added at the beginning of the third stage.

[0025] S4, In-situ anchoring and color fixing Twenty minutes after the start of the third heat treatment, a multifunctional anchoring agent solution was slowly injected into the dye bath. The anchoring agent was the reaction product of hyperbranched polyethyleneimine and epichlorohydrin, wherein the molecular weight of the hyperbranched polyethyleneimine was 20,000, and the molar ratio of hyperbranched polyethyleneimine to epichlorohydrin was 1:120. The amount of anchoring agent used was 10% of the total weight of the reactive dye and disperse dye, and the injection time was 15 minutes.

[0026] S5, Gradient cooling shaping After the staining and heat preservation were completed, the temperature was lowered to 75℃ at a rate of 0.8℃ / min, then to 45℃ at a rate of 2.5℃ / min, and finally to room temperature (25℃) at a rate of 0.2℃ / min.

[0027] S6, Microbubble Cleaning Micro-nanobubbles were used to clean the dyed fabric. The micro-nanobubbles had a diameter of 200–500 nm, the cleaning temperature was 70℃, the cleaning time was 15 min, the gas-liquid ratio was 1:8, and the pH was 7.5. The micro-nanobubbles carried a negative charge on their surface.

[0028] S7, Low Temperature Setting The washed fabric was heat-set at 140℃ for 45 seconds. Example 2:

[0029] The difference between this embodiment and Embodiment 1 is that: The fabric is pure cotton. In step S1, the biological enzyme is cellulase, the dosage is 0.5 g / L, the treatment temperature is 45℃, the treatment time is 40 min, and the bath ratio is 1:15. The third stage of heating in step S2 ends at 98℃, and the temperature is maintained for 50 minutes. In step S4, the amount of anchoring agent used is 8% of the total weight of reactive dye and disperse dye, and the injection time is 20 min. In step S7, the setting temperature is 135℃ and the setting time is 50s.

[0030] The remaining steps and parameters are the same as in Example 1. Example 3:

[0031] The difference between this embodiment and Embodiment 1 is that: The fabric is nylon. In step S1, the biological enzyme is polyamide hydrolase, with a dosage of 2.0 g / L; the activator 1-ethyl-3,3-dimethylaminopropylcarbodiimide hydrochloride is used at a dosage of 1.0 g / L; the penetrant JFC is used at a dosage of 1.5 g / L; the treatment temperature is 55℃; the treatment time is 20 min; and the bath ratio is 1:10. In step S2, the third stage of heating ends at 100℃ and is held for 60 minutes. In step S3, the amount of dimethyl sulfoxide added is 5% of the dye bath volume, the amount of sodium sulfate added is 15 g / L, and the amount of surfactant added is 0.5 g / L. In step S4, the anchoring agent is the reaction product of hyperbranched polyethyleneimine and epichlorohydrin, wherein the molecular weight of hyperbranched polyethyleneimine is 30,000, the molar ratio of hyperbranched polyethyleneimine to epichlorohydrin is 1:200, the amount of anchoring agent is 15% of the total weight of reactive dye and disperse dye, and the injection time is 10 min. In step S5, the cooling rates are 1.0℃ / min, 3.0℃ / min, and 0.3℃ / min, respectively. In step S6, the cleaning temperature is 80℃, the cleaning time is 10 min, the gas-liquid ratio is 1:10, and the pH is 8.5. In step S7, the setting temperature is 150℃ and the setting time is 30s.

[0032] The remaining steps and parameters are the same as in Example 1. Example 4:

[0033] The difference between this embodiment and Embodiment 1 is that: The fabric is a cotton-nylon blend, with cotton accounting for 50% of the total mass and nylon accounting for 50% of the total mass. The third stage of heating in step S2 ends at 105℃, and the temperature is maintained for 50 minutes. In step S3, the amount of dimethyl sulfoxide added is 2% of the dye bath volume, the amount of sodium sulfate added is 5 g / L, and the amount of surfactant added is 0.1 g / L. In step S4, the anchoring agent is the reaction product of hyperbranched polyethyleneimine and epichlorohydrin, wherein the molecular weight of hyperbranched polyethyleneimine is 10,000, the molar ratio of hyperbranched polyethyleneimine to epichlorohydrin is 1:40, the amount of anchoring agent is 5% of the total weight of reactive dye and disperse dye, and the injection time is 20 min. In step S5, the cooling rates are 0.5℃ / min, 2.0℃ / min, and 0.1℃ / min, respectively. In step S6, the cleaning temperature is 60℃, the cleaning time is 20 min, the gas-liquid ratio is 1:5, and the pH is 7.0. In step S7, the setting temperature is 130℃ and the setting time is 60s.

[0034] The remaining steps and parameters are the same as in Example 1.

[0035] Comparative Example 1: This comparative example uses a conventional staining process, and differs from Example 1 in that: Step S1 activation pretreatment is not performed; Step S2 adopts a conventional two-stage heating method, heating from room temperature to 85℃ at a rate of 1.0℃ / min and holding for 30 min, and then heating to 110℃ at a rate of 1.0℃ / min and holding for 45 min. Step S3, dielectric polarity adjustment, is not performed; Step S4 employs an independent color-fixing process after dyeing, with a conventional cationic color-fixing agent dosage of 20 g / L, and treatment at 60°C for 30 min. Step S5 uses natural cooling to lower the temperature without controlling the cooling rate; Skip the S6 microbubble cleaning step and use regular soap washing at 95°C for 20 minutes. Step S7: The setting temperature is 180℃, and the setting time is 60s.

[0036] The rest is the same as in Example 1.

[0037] Comparative Example 2: The difference between this comparative example and Example 1 is as follows: Step S2 adopts a conventional two-stage heating method, heating from room temperature to 85℃ at a rate of 1.0℃ / min and holding for 30 min, and then heating to 110℃ at a rate of 1.0℃ / min and holding for 45 min. Step S3, dielectric polarity adjustment, is not performed; Step S5 uses natural cooling to lower the temperature without controlling the cooling rate; The remaining steps, including activation pretreatment, in-situ anchoring and color fixing, microbubble cleaning, and low-temperature shaping, are the same as in Example 1.

[0038] Comparative Example 3: The difference between this comparative example and Example 1 is as follows: Without performing step S4 in-situ anchoring and color fixation, the dyeing fixation agent was used for finishing, with a dosage of 30 g / L, and the treatment was carried out at 60℃ for 30 min. Step S5 uses natural cooling to lower the temperature without controlling the cooling rate; Step S7: The setting temperature is 180℃, and the setting time is 60s. The remaining steps, including activation pretreatment, gradient temperature staining, medium polarity control, and microbubble washing, are the same as in Example 1.

[0039] The dyed fabrics obtained in Examples 1-4 and Comparative Examples 1-3 were subjected to the following performance tests: Wash fastness test: The test was conducted according to Test Method 2A of AATCC TM61-2013. The test conditions were: temperature 49℃, washing liquid was 0.15% of the total volume of 1993 AATCC standard detergent, liquor ratio 1:50, number of steel balls 50, and time 45 min. The sample size was 50 mm × 150 mm. The sample was sewn together with No. 10 multifiber lining fabric, placed in a stainless steel container, and run in a washing color fastness tester at a rate of 40 ± 2 rpm for 45 min. The sample was removed, rinsed three times with water at 40 ± 3℃, squeezed dry, and dried in an oven not exceeding 71℃. After drying, it was conditioned for 1 h at a temperature of 21 ± 1℃ and a relative humidity of 65 ± 2%. The color change grade of the sample and the staining grade of each fiber component on the multifiber lining were evaluated using a gray scale. The test results are shown in Table 1.

[0040] Table 1: Results of color fastness to washing tested according to Test Method 2A in AATCC TM61-2013 standard

[0041] Color fastness to rubbing test: The test was conducted according to the friction tester method in the AATCC TM8-2016 standard. The samples were cut into 50mm × 130mm pieces, with the long side of the sample forming a 45° angle with both the warp and weft directions. For the dry friction test, the sample was placed on the base of the rubbing color fastness tester, and rubbed back and forth ten times with a dry AATCC standard white rubbing cloth. For the wet friction test, the AATCC standard white rubbing cloth was completely soaked in distilled water, then removed and rubbed back and forth ten times with a roller to control the moisture content to 65±5%. After the rubbing was completed, the white rubbing cloth was removed, and the staining grade was assessed using the AATCC 9-level color migration scale. The test results are shown in Table 2.

[0042] Table 2: Results of color fastness to rubbing tested according to AATCC TM8-2016 standard

[0043] Storage color fastness test: Dye migration tests were conducted according to AATCC methods. The dyed sample was placed in close contact with undyed white cotton fabric and left for 24 hours at 49°C and 80% relative humidity. After removal, the degree of staining on the white cotton fabric was assessed using a gray scale rating. The test results are shown in Table 3.

[0044] Table 3: Results of dye migration test for color fastness during storage

[0045] Dimensional stability test: The test was conducted according to the AATCC TM135-2018 standard for testing fabric dimensional changes after household washing. Reference dimensions were marked on the fabric, with three sets each for length and width, spaced 250 mm apart. The fabric was conditioned for 4 hours under standard atmospheric conditions (temperature 21±1℃, relative humidity 65±2%) before initial dimensions were measured. The fabric was then washed and tumble dried according to the standard washing procedure, with a washing water temperature of 60℃, medium agitation, and a normal washing cycle. This was repeated three times. After the final wash and dry, the fabric was conditioned for 4 hours under standard atmospheric conditions, and the marking intervals were measured again to calculate the percentage dimensional change. The test results are shown in Table 4.

[0046] Table 4: Dimensional stability results tested according to AATCC TM135-2018 standard

[0047] Floating color rate test: The floating color rate of the dyed fabric was determined by spectrophotometry. 2g each of the dyed fabric (unwashed and washed) were placed in 100mL of pyridine aqueous solution (50% by volume) and extracted at 60℃ for 30min. The absorbance of the extract was measured using a UV-Vis spectrophotometer at the wavelength of maximum dye absorption. The floating color rate was calculated using the following formula: Floating color rate = (A1 - A2) / A1 multiplied by 100%. Where A1 is the absorbance of the extract before washing, and A2 is the absorbance of the extract after washing. The test results are shown in Table 5.

[0048] Table 5: Results of Floating Color Rate Test

[0049] Colorfastness retention test after thermal migration: The dyed fabric was subjected to dry heat treatment at 180℃ for 60 seconds to simulate the high-temperature setting conditions of post-treatment. Then, the color fastness to washing after heat treatment was tested according to test method 2A in AATCC TM61-2013. The color fastness retention rate after heat migration was calculated using the following formula: Retention rate = (Color fastness grade after heat treatment) / (Color fastness grade before heat treatment) multiplied by 100%. The test results are shown in Table 6.

[0050] Table 6: Results of Colorfastness Retention Rate Test After Thermal Migration

[0051] Vertical wicking height test: The vertical wicking height of the fabric was determined according to the AATCC test method. The sample was cut into strips with a warp length of 250 mm and a width of 25 mm. One end was fixed to an iron stand, and the other end was vertically immersed in distilled water to a depth of 10 mm. The height the water rose along the fabric within 120 seconds was recorded; this recorded height is the vertical wicking height of the fabric. The test results are shown in Table 7.

[0052] Table 7: Test Results of Vertical Core Suction Height

[0053] Odor control performance test: The odor control performance of the fabric was tested using a sensory rating method. The samples were placed in a sealed container and left for 24 hours at 37°C and 90% relative humidity. Five trained rating personnel rated the odor intensity of the samples, with level 1 indicating a strong odor and level 5 indicating no odor. The average rating score of the five personnel was taken as the final rating result. The test results are shown in Table 8.

[0054] Table 8: Odor Control Performance Test Results

[0055] Fabric pH test: The pH value of the fabric was tested according to the relevant AATCC method. A 2g sample was cut into small pieces and placed in 100mL of distilled water. The mixture was extracted by shaking at room temperature for 1 hour, and the pH value of the extract was measured using a pH meter. The test results are shown in Table 9.

[0056] Table 9: Results of pH test on fabric

[0057] The test results in Tables 1 to 9 above show that: 1. In Examples 1-4 of this invention, the color fastness to washing all reached grade 4.0 or higher, the staining of acetate and nylon all reached grade 3.5 or higher, and the staining of other fibers all reached grade 4.0 or higher. Comparative Example 1, using conventional processes, showed a color fastness of only grade 3.0, and staining of acetate and nylon only reached grade 2.5. Comparative Example 2 did not use gradient heating and medium control, and Comparative Example 3 did not use in-situ anchoring fixation; both showed significantly lower color fastness indices than the Examples. This demonstrates that there is a synergistic effect among the gradient heating dyeing, medium polarity control, and in-situ anchoring fixation of this invention, and none of them can be omitted. 2. As shown in Table 6, after dry heat treatment at 180℃ for 60s, the color fastness retention rate of Examples 1-4 of the present invention all reached over 87.5%, while that of Comparative Example 1 was only 50.0%, Comparative Example 2 was 57.1%, and Comparative Example 3 was 66.7%. This indicates that the medium polarity regulation and gradient thermal process of the present invention can effectively suppress the thermal migration of disperse dyes; 3. As shown in Table 5, the floating color rate of Examples 1-4 of the present invention is only 3.0%-4.0%, while that of Comparative Example 1 is as high as 18.5%, Comparative Example 2 is 12.0%, and Comparative Example 3 is 10.5%. This indicates that the gradient temperature dyeing and in-situ anchoring fixation of the present invention significantly reduce the floating color rate from the source of the main dyeing process. 4. As shown in Table 4, the warp shrinkage rate of Examples 1 to 4 of the present invention is -1.0% to -1.5%, and the weft shrinkage rate is -0.5% to -1.0%, while the warp shrinkage rate of Comparative Example 1 is -3.5%, and the weft shrinkage rate is -3.0%. This indicates that the gradient cooling and shaping of the present invention can effectively improve the dimensional stability of the fabric.

[0058] In summary, as shown in Tables 1 to 9, Examples 1 to 4 of the present invention are significantly superior to Comparative Examples 1 to 3 in terms of color fastness, dimensional stability, floating color rate, heat migration inhibition, wicking performance, odor control, and pH value. In particular, Example 1 achieved the best overall performance on cotton-polyester blended fabrics, with a color change rate of 4.5 for wash fastness, a staining rate of 4.0 for both acetate and nylon, a wet rubbing fastness of 4.0, a floating color rate of only 3.2%, and a color fastness retention rate of 88.9% after heat migration. All indicators meet the AATCC standard requirements for color fastness of high-quality textiles.

[0059] This invention employs a seven-step coupled process: activation pretreatment, gradient temperature dyeing, medium polarity control, in-situ anchoring and fixing, gradient temperature setting, microbubble cleaning, and low-temperature setting. This systematically addresses the core technical shortcomings of existing technologies, such as high floating rates of reactive dyes, severe thermal migration of disperse dyes, significant cross-staining in blended fabrics, and ecotoxicity of traditional fixing techniques, all stemming from the source of the dyeing process. Test data from Examples 1-4 fully demonstrate the effectiveness and superiority of this invention. Each example achieved excellent comprehensive performance under different fabric types and process parameters, indicating that this invention has good process adaptability and industrial scalability.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dyeing process for improving the color fastness of textile fabrics, characterized in that: Includes the following steps: S1. Activation pretreatment: The fabric is pretreated by immersing it in a treatment solution containing biological enzymes and activators. S2. Gradient Temperature Dyeing: The pretreated fabric is placed in the dye bath and dyed according to a three-stage gradient temperature rise curve. The three-stage gradient temperature rise includes: The first stage involves heating from room temperature to 60–70°C at a rate of 0.5–1.0°C / min and holding at that temperature for 15–25 minutes. The second stage involves heating to 80–90°C at a rate of 0.8–1.2°C / min and holding at that temperature for 20–30 minutes. The third stage involves heating to 95–130°C at a rate of 0.3–0.6°C / min and holding at that temperature for 30–60 min. S3. Medium polarity control: During the gradient temperature dyeing process, add 2-5% organic solvent (by volume of the dye bath) to the dye bath after the first stage, add 5-15 g / L of neutral electrolyte after the second stage, and add 0.1-0.5 g / L of surfactant at the beginning of the third stage. S4. In-situ anchoring and fixing: 15-30 minutes after the start of the third stage of heat preservation, inject a multifunctional anchoring agent solution into the dye bath. The amount of anchoring agent is 5-15% of the weight of the dye, and the injection time is 10-20 minutes. S5. Gradient cooling and setting: After staining and heat preservation, cool down to 70-80℃ at a rate of 0.5-1.0℃ / min, then cool down to 40-50℃ at a rate of 2-3℃ / min, and finally cool down to room temperature at a rate of 0.1-0.3℃ / min. The room temperature is 25±5℃. S6. Microbubble cleaning: Micro-nano bubbles are used to clean the dyed fabric. The bubble diameter is 100nm~10μm, the cleaning temperature is 60~80℃, and the cleaning time is 10~20min. S7. Low-temperature setting: Heat setting is carried out at 130-150℃ for 30-60 seconds.

2. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S1, the bioenzyme is a polyamide hydrolase or a cellulase, and the dosage is 0.5 to 2.0 g / L.

3. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S1, the activator is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride.

4. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S3, the organic solvent is dimethyl sulfoxide.

5. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S4, the multifunctional anchoring agent is the reaction product of hyperbranched polyethyleneimine and epichlorohydrin, wherein the molecular weight of the hyperbranched polyethyleneimine is 10,000 to 30,000, and the molar ratio of the hyperbranched polyethyleneimine to epichlorohydrin is 1:40 to 200.

6. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: The fabric is a blend of one or more of cotton, polyester, and nylon.

7. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S1, the pH of the treatment solution is 6.5 to 7.5, the treatment temperature is 45 to 55°C, the treatment time is 20 to 40 minutes, and the bath ratio is 1:10 to 1:

15.

8. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S6, the surface of the micro-nano bubbles carries a negative charge.

9. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S6, the gas-liquid ratio is 1:5 to 1:10, and the pH is 7.0 to 8.

5.

10. The dyeing process for improving the color fastness of textile fabrics according to claim 1, characterized in that: In step S1, the treatment solution also contains a penetrant JFC, with a dosage of 0.5 to 1.5 g / L.

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