Polyester knitted dyed cloth and production method thereof

Abstract

The invention discloses polyester knitted dyed cloth and a production method thereof.The polyester knitted dyed cloth adopts special-shaped cross section polyester fibers as raw materials, the cross section of each polyester fiber is of a multi-leaf shape or a hollow structure, and the production method sequentially comprises the following steps of S1, fiber pretreatment and spinning, S2, knitting, S3, pretreatment, S4, multi-stage gradient dyeing and S5, aftertreatment. According to the method, the special-shaped cross-section fiber is adopted and combined with low-temperature plasma treatment, so that a solid foundation is provided for dye adsorption and permeation; a multi-stage gradient dyeing process and a temperature response type slow-release color fixing agent are combined, so that an excellent dyeing effect is obtained; compared with a traditional process, the composite biological refining enzyme agent has the advantages that the energy consumption and the dosage of chemicals are greatly reduced; the temperature response type slow-release color fixing agent realizes accurate and automatic control of pH, avoids waste, reduces chemical load, and is more environment-friendly and energy-saving; functional treatments such as rare earth complexing deepening and anti-ultraviolet finishing are integrated in the final stage of dyeing, so that the subsequent finishing procedure is omitted, the period is shortened, the cost is reduced, and fiber damage is avoided.

Description

Technical Field

[0001] This invention belongs to the field of textile technology, specifically, it relates to a polyester knitted dyed fabric and its production method. Background Technology

[0002] Polyester knitted fabrics are widely used in clothing, home furnishings, and other fields due to their excellent strength, elasticity, and wrinkle resistance. Dyeing is a key process that gives them color and value. However, the inherent characteristics of polyester fibers, such as their dense structure, strong hydrophobicity, and high glass transition temperature, present many challenges to their dyeing process.

[0003] The current mainstream dyeing process for polyester knitted fabrics is high-temperature, high-pressure dyeing, which faces several technical bottlenecks in practice: First, poor dyeing uniformity and penetration. The tight yarn structure of polyester fibers makes it difficult for dye to diffuse into the fiber interior, especially for medium to dark-colored products, easily leading to ring dyeing (i.e., dye only adheres to the fiber surface and not the interior), resulting in poor color fastness (such as rubbing fastness) and dull, insufficient color saturation. Second, high energy consumption and complex processes. To achieve sufficient dyeing depth and fastness, traditional processes often rely on extending dyeing time, increasing dyeing temperature (usually above 130℃), and using large amounts of chemical auxiliaries (such as carriers and leveling agents). This not only leads to huge energy consumption and increased production costs, but also imposes a heavy environmental burden due to excessive use of auxiliaries. Third, cumbersome functional finishing processes. To impart functions such as UV resistance and color deepening to the fabric, finishing processes are usually required after dyeing, which increases the complexity and time cost of the production process, and may also affect the quality of the final product due to compatibility issues between processes.

[0004] To address these issues, the industry has explored various technologies. For example, cationic modifiers are used to pretreat polyester to improve its dyeability, or nano-dyes are used to enhance penetration. However, these methods often only solve a single problem and may introduce new defects, such as modifiers affecting fabric hand feel or nano-dyes exhibiting poor dispersion stability. Furthermore, traditional acid / alkali pH adjustment methods are difficult to achieve precise and stable control in high-temperature, high-pressure dyeing vats, thus affecting dyeing reproducibility and color fixation.

[0005] Therefore, developing a production method for polyester knitted dyed fabric that can significantly improve dye penetration and dyeing effect, achieve energy saving and consumption reduction, simplify process flow, and integrate multi-functional finishing has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a polyester knitted dyed fabric and its production method, the details of which are as follows: A polyester knitted dyed fabric, the production method of which includes the following steps: S1 Fiber Pretreatment and Spinning: Low-temperature plasma treatment is performed on polyester fibers with irregular cross-sections that have multi-leaf or hollow structures. The treatment power is 200-400W and the treatment time is 2-5min. The treated fibers are then spun into high-count yarns of 50-80S using the Siro compact spinning process. S2 knitting: Using the high-count yarn, knitting is done on a fine gauge knitting machine with a gauge of 28 needles / inch or higher to produce single jersey or mesh fabric. S3 Pretreatment: Place the knitted fabric in a treatment solution containing a compound bio-refining enzyme and treat it at 50-55℃ and pH 6.0-7.0 for 30-40 minutes to fully biodegrade and remove spinning oils and waxes; S4 multi-stage gradient staining: (1) Add water and fiber swelling accelerator to the dyeing equipment, adjust the bath ratio to 1:8 to 12, raise the temperature to 65 to 70°C at a rate of 2 to 3°C / min, and run for 10 to 15 minutes; (2) Add the composite nano dye and continue to slowly heat to 75-80℃ at a rate of 0.5-1℃ / min, and keep it at that temperature for 15-20min; (3) Add the temperature-responsive slow-release fixing agent, which releases citric acid when the temperature is raised to 90-95°C, automatically adjusting the pH of the system to 4.5-5.0, and keep it at this temperature for 25-35 minutes; (4) Cool the system temperature to 70-80℃, add the multifunctional compound additive, and run for 15-20 minutes; S5 Post-treatment: After the dyed fabric is washed with cold water, neutralized, soaped, washed with hot water and softened, it is dried and shaped using low-tension airflow, with the soaping temperature range being 95-98℃.

[0007] Furthermore, in step S3, the composite biorefining enzyme used is a combination of lipase, protease, and alkyl glycoside APG. The composite biorefining enzyme (lipase, protease, and alkyl glycoside APG) biodegrades the components of polyester oils and waxes, exhibiting mild action conditions, high specificity, and excellent detergency. Moreover, the biodegradability of the enzymes makes its environmental advantages particularly prominent.

[0008] Furthermore, in step S4, the fiber swelling accelerator is one of benzyl benzoate, o-phenylphenol, or methyl salicylate. The selected fiber swelling accelerators (such as benzyl benzoate) are all highly efficient and environmentally friendly carriers that can significantly reduce the glass transition temperature of polyester fibers, promote full swelling of the fibers at the dyeing temperature, and open channels for the rapid penetration of nano-dye molecules, thereby shortening the dyeing time and increasing the dyeing rate.

[0009] Furthermore, in step S4, the composite nano-dye is a nanoscale disperse dye encapsulated with a cationic modifier, wherein the cationic modifier is 3-chloro-2-hydroxypropyltrimethylammonium chloride or glycidyltrimethylammonium chloride. The cationic modifier modifies the surface of polyester fibers, imparting cationic properties, and generates strong ionic bonds with the anionic disperse dye, greatly improving the dyeing rate and final color depth, thus solving the problem of dyeing polyester to dark colors.

[0010] Furthermore, in step S4, the temperature-responsive sustained-release fixing agent is a mixture of citric acid and ammonium sulfate encapsulated in polypropylene microcapsules. The temperature-responsive sustained-release fixing agent (microcapsule-encapsulated citric acid and ammonium sulfate) enables the targeted and quantitative release of the acid at a specific high temperature trigger, ensuring the accuracy and stability of the pH environment throughout the fixing process. This eliminates the need for manual intervention, significantly improving dyeing reproducibility and product quality consistency.

[0011] Furthermore, in step S4, the multifunctional compounded agent is composed of a rare earth complexing deepening agent and a polymeric UV-resistant finishing agent in a mass ratio of 1:1 to 3. The compounding of the rare earth complexing deepening agent and the polymeric UV-resistant finishing agent utilizes the complexation effect of rare earth ions with dye molecules to achieve optical deepening, while simultaneously imparting long-lasting UV resistance to the fabric, achieving two benefits in one and realizing a multifunctional integrated finishing process.

[0012] Furthermore, the rare earth complex deepening agent is a cerium chloride-fatty alcohol polyoxyethylene ether complex or a lanthanum nitrate-polyethylene glycol complex; the polymeric UV-resistant finishing agent is one of nano-titanium dioxide, UV-P, or UV-327. Rare earth complexes such as cerium chloride / lanthanum nitrate can effectively improve the dye's absorption rate of light energy and reduce surface light reflection, resulting in a significant deepening effect; nano-titanium dioxide and benzotriazole UV absorbers efficiently shield ultraviolet rays through both reflection and absorption mechanisms, jointly endowing the fabric with excellent functionality.

[0013] Furthermore, the multi-stage gradient staining process in step S4 is performed entirely in an ultrasound-assisted device, with an ultrasound frequency of 25–40 kHz and a power density of 0.3–0.5 W / cm². 2 The cavitation effect of ultrasound can generate extremely strong mechanical force, which can destroy the static liquid film on the fiber surface, promote dye liquor circulation, and force dye molecules to diffuse into the fiber interior, thereby significantly improving the dyeing rate and levelness, and is especially beneficial for solving the penetration problem of high-count and high-density fabrics.

[0014] Furthermore, in step S5, an aminoethylaminopropylpolydimethylsiloxane microemulsion is used for softening treatment at a temperature of 40–45°C. The amino groups in the aminoethylaminopropylpolydimethylsiloxane microemulsion form a strong oriented adsorption with the fibers, giving the fabric a durable, smooth, and full hand feel without affecting its original color and functionality.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: I. In this invention, by employing irregularly shaped cross-section fibers and combining them with low-temperature plasma treatment, the specific surface area and surface energy of the fibers are greatly increased, providing a solid foundation for dye adsorption and penetration. By combining a multi-stage gradient dyeing process with a temperature-responsive slow-release fixing agent, optimal dyeing and fixing conditions are created, effectively solving the "ring dyeing" problem and allowing the dye to fully penetrate into the fiber interior, thereby achieving excellent dyeing depth (K / S value), uniformity, and color fastness (such as rubbing and washing fastness).

[0016] Second, in this invention, the compound bio-refining enzyme can efficiently remove spinning oils and waxes under near-neutral conditions at low temperatures (50-55℃), significantly reducing energy consumption and chemical usage compared to traditional high-temperature strong alkali refining processes. The temperature-responsive slow-release fixing agent enables precise and automatic pH control, avoiding the instability and waste of manually added acid agents, reducing salt and chemical load in wastewater, and making the entire production process more environmentally friendly and energy-efficient.

[0017] Third, in this invention, rare earth complexation enhancement and functional treatments such as UV protection are integrated and completed at the end of the dyeing stage, achieving efficient synchronization of "dyeing-functional finishing", eliminating the need for subsequent separate finishing processes, shortening the production cycle, reducing overall costs, and avoiding damage to the fibers that may be caused by multiple processing steps.

[0018] Fourth, in this invention, the microencapsulation technology used in the temperature-responsive slow-release fixing agent can rapidly and quantitatively release the acid agent when the dye liquor reaches the optimal fixing temperature window (90-95℃), achieving automatic and stable pH adjustment. This avoids the sudden changes in local pH or uneven concentration caused by delayed operation, uneven addition speed, and insufficient mixing in traditional manual addition methods. As a result, it effectively eliminates problems such as color spots, color differences, and uneven dyeing caused by these issues, greatly improving dyeing reproducibility and single-dye pass rate, and reducing quality risks and production costs caused by human error. Detailed Implementation

[0019] To enable those skilled in the art to understand the features and effects of this application, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art in this application, and in case of conflict, the definitions in this specification shall prevail.

[0020] The present application will be described below with reference to specific embodiments and examples. It should be understood that these specific embodiments and examples are merely illustrative and are not intended to limit the scope or use of the present application.

[0021] Unless otherwise stated, the methods, reagents, and conditions used in the preparation examples, comparative examples, and embodiments described below are conventional methods, reagents, and conditions in the art.

[0022] Unless otherwise specified, in this application, parts by weight represent the relative number of mass parts in the composition, which can be any mass unit, such as, but not limited to, kilograms, grams, etc.

[0023] The specific embodiments are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise specified, the raw materials and reagents used in the examples are commercially available.

[0024] Example 1 S1 Fiber Pretreatment and Spinning: Low-temperature plasma treatment is performed on polyester fibers with irregular cross-sections that have multi-leaf or hollow structures. The treatment power is 300W and the treatment time is 4min. The treated fibers are then spun into 60S high-count yarns using Siro compact spinning process. S2 knitting: a single-sided jersey or mesh fabric woven on a fine-gauge knitting machine with high-count yarns at a gauge of 30 needles per inch. S3 Pretreatment: The knitted fabric is placed in a treatment solution containing a compound biorefining enzyme and treated at 52°C and pH 6.6 for 35 minutes to fully biodegrade and remove spinning oil and wax; wherein, the compound biorefining enzyme is a combination of lipase, protease and alkyl glycoside APG. S4 multi-stage gradient staining (all the following steps are performed using an ultrasound-assisted device with an ultrasound frequency of 32 kHz and a power density of 0.4 W / cm²). 2 ): (1) Add water and fiber swelling accelerator to the dyeing equipment, adjust the bath ratio to 1:10, raise the temperature to 68℃ at a rate of 2.4℃ / min, and run for 12min; wherein, the fiber swelling accelerator is benzyl benzoate.

[0025] (2) Add the composite nano dye and continue to slowly heat up to 78°C at a rate of 0.8°C / min, and keep it at that temperature for 16 min; wherein, the composite nano dye is a nano-scale disperse dye coated with a cationic modifier, and the cationic modifier is 3-chloro-2-hydroxypropyltrimethylammonium chloride; (3) Add a temperature-responsive slow-release fixing agent. The fixing agent releases citric acid when the temperature is raised to 92°C, automatically adjusting the pH of the system to 4.8. Keep the system at this temperature for 30 minutes. The temperature-responsive slow-release fixing agent is a mixture of citric acid and ammonium sulfate encapsulated in polypropylene microcapsules. (4) Reduce the system temperature to 75℃, add the multifunctional compound additive, and run for 18 minutes; wherein, the multifunctional compound additive is composed of rare earth complexing agent and polymer UV-resistant finishing agent in a mass ratio of 1:2, the rare earth complexing agent is cerium chloride-fatty alcohol polyoxyethylene ether complex; the polymer UV-resistant finishing agent is nano titanium dioxide. S5 Post-treatment: After the dyed fabric is washed with cold water, neutralized, soaped, washed with hot water and softened, it is dried and shaped using low-tension airflow, with the soaping temperature range being 96℃; the softening treatment is carried out using aminoethylaminopropyl polydimethylsiloxane microemulsion at a temperature of 42℃.

[0026] Example 2 S1 Fiber Pretreatment and Spinning: Low-temperature plasma treatment is performed on polyester fibers with irregular cross-sections that have multi-leaf or hollow structures. The treatment power is 200W and the treatment time is 5min. The treated fibers are then spun into 50S high-count yarns through Siro compact spinning process. S2 knitting: a single-sided jersey or mesh fabric woven on a fine gauge knitting machine with high-count yarns at 28 gauges / inch. S3 Pretreatment: The knitted fabric is placed in a treatment solution containing a compound biorefining enzyme and treated at 55°C and pH 6.0 for 40 minutes to fully biodegrade and remove spinning oils and waxes; wherein, the compound biorefining enzyme is a combination of lipase, protease and alkyl glycoside APG. S4 multi-stage gradient staining (all the following steps are performed using an ultrasound-assisted device at a frequency of 25 kHz and a power density of 0.5 W / cm²). 2 ): (1) Add water and fiber swelling accelerator to the dyeing equipment, adjust the bath ratio to 1:8, heat to 65℃ at a rate of 3℃ / min, and run for 15min; wherein, the fiber swelling accelerator is methyl salicylate.

[0027] (2) Add the composite nano dye and continue to slowly heat up to 80°C at a rate of 0.5°C / min, and keep it at that temperature for 15 min; wherein, the composite nano dye is a nano-scale disperse dye coated with a cationic modifier, and the cationic modifier is glycidyltrimethylammonium chloride. (3) Add a temperature-responsive slow-release fixing agent. The fixing agent releases citric acid when the temperature is raised to 95°C, automatically adjusting the pH of the system to 4.5. Keep the system at this temperature for 35 minutes. The temperature-responsive slow-release fixing agent is a mixture of citric acid and ammonium sulfate encapsulated in polypropylene microcapsules. (4) Reduce the system temperature to 70℃, add the multifunctional compound additive, and run for 20 minutes; wherein, the multifunctional compound additive is composed of rare earth complexing agent and polymer UV-resistant finishing agent in a mass ratio of 1:1, the rare earth complexing agent is lanthanum nitrate-polyethylene glycol complex; the polymer UV-resistant finishing agent is UV-P; S5 Post-treatment: After the dyed fabric is washed with cold water, neutralized, soaped, washed with hot water and softened, it is dried and shaped using low-tension airflow, with the soaping temperature range being 98℃; the softening treatment is carried out using aminoethylaminopropyl polydimethylsiloxane microemulsion at a temperature of 40℃.

[0028] Example 3 S1 Fiber Pretreatment and Spinning: Low-temperature plasma treatment is performed on polyester fibers with irregular cross-sections that have multi-leaf or hollow structures. The treatment power is 400W and the treatment time is 2min. The treated fibers are then spun into 80S high-count yarns through Siro compact spinning process. S2 knitting: a single-sided jersey or mesh fabric woven on a fine gauge knitting machine with high-count yarns at 32 gauges / inch. S3 Pretreatment: The knitted fabric is placed in a treatment solution containing a compound biorefining enzyme and treated at 50°C and pH 7.0 for 30 minutes to fully biodegrade and remove spinning oils and waxes; wherein, the compound biorefining enzyme is a combination of lipase, protease and alkyl glycoside APG. S4 multi-stage gradient staining (all the following steps are performed using an ultrasound-assisted device at a frequency of 40 kHz and a power density of 0.3 W / cm²) 2 ): (1) Add water and fiber swelling accelerator to the dyeing equipment, adjust the bath ratio to 1:12, heat to 70°C at a rate of 2°C / min, and run for 10 min; wherein, the fiber swelling accelerator is o-phenylphenol.

[0029] (2) Add the composite nano dye and continue to slowly heat up to 75°C at a rate of 1°C / min, and keep it at that temperature for 20 min; wherein, the composite nano dye is a nano-scale disperse dye coated with a cationic modifier, and the cationic modifier is 3-chloro-2-hydroxypropyltrimethylammonium chloride. (3) Add a temperature-responsive slow-release fixing agent. The fixing agent releases citric acid when the temperature is raised to 90°C, automatically adjusting the pH of the system to 5.0. Keep the system at this temperature for 25 minutes. The temperature-responsive slow-release fixing agent is a mixture of citric acid and ammonium sulfate encapsulated in polypropylene microcapsules. (4) Reduce the system temperature to 80℃, add the multifunctional compound additive, and run for 15 minutes; wherein, the multifunctional compound additive is composed of rare earth complexing agent and polymer UV-resistant finishing agent in a mass ratio of 1:3, the rare earth complexing agent is cerium chloride-fatty alcohol polyoxyethylene ether complex; the polymer UV-resistant finishing agent is UV-P; S5 Post-treatment: After the dyed fabric is washed with cold water, neutralized, soaped, washed with hot water and softened, it is dried and shaped using low-tension airflow, with the soaping temperature range being 95℃; the softening treatment is carried out using aminoethylaminopropyl polydimethylsiloxane microemulsion at a temperature of 45℃.

[0030] Comparative Example 1 Traditional dyeing process is adopted, that is, ordinary round cross-section polyester fiber is used without plasma treatment; the pretreatment is high temperature alkali refining (NaOH 2g / L, refining agent 1g / L, 90℃×30min); the dyeing uses conventional disperse dye (non-nano) and traditional process (130℃×45min), and the pH is manually adjusted to 4.5 with glacial acetic acid; after color fixation, UV protection finishing (pad baking method) is required separately.

[0031] Comparative Example 2 Ordinary circular cross-section polyester fibers were used, and low-temperature plasma treatment was not performed. All other steps were exactly the same as in Example 1.

[0032] Comparative Example 3 The same raw materials and pretreatment as in Example 1 were used, but instead of using a temperature-responsive slow-release fixing agent during dyeing, the pH was adjusted by manually adding a mixture of citric acid and ammonium sulfate in equal amounts to those in the microcapsules when the temperature was raised to 90°C.

[0033] Comparative Example 4 Instead of adding multifunctional compound additives, the fabric is subjected to UV-resistant finishing in another bath using a traditional pad-bake process, with all other steps being exactly the same as in Example 1.

[0034] The samples obtained in Examples 1-3 and Comparative Examples 1-4 were subjected to the following performance tests: 1. Apparent color depth (K / S value) test: Measured using a spectrophotometer. The higher the K / S value, the deeper the color. 2. Color fastness (rubbing fastness) test: Test dry and wet rubbing fastness according to AATCC8 or ISO105-X12 standards (grades 1-5, the higher the grade, the better); 3. Energy consumption comparison test: Record the total power consumption from S3 pretreatment to the end of S4 staining (which can be measured using an electricity meter).

[0035] 4. UV protection performance (UPF value) test: The UV protection factor (UPF) is tested according to AATCC183 standard. A UPF>40 is sufficient to be called a UV-resistant fabric.

[0036] 5. Hand feel (subjective evaluation + hardness) test: The hand feel was ranked by multiple professionals in a blind evaluation (best > second best > worst). Alternatively, a fabric hardness tester can be used to test the bending length. The smaller the value, the softer the hand feel.

[0037] The test results are shown in the table below: Testing items Comparative Example 1 (Traditional Process) Comparative Example 2 (without plasma) Comparative Example 3 (artificially adjusted pH) Comparative Example 4 (Step-by-step summary) Example 1 Example 2 Example 3 Apparent color depth (K / S value) 12.5 16.8 20.1 20.3 25.6 24.9 25.3 Dry rubbing fastness (grade) 4-5 4-5 4-5 4-5 4-5 4-5 4-5 Wet rubbing fastness (grade) 2-3 3 3-4 3-4 4-5 4 4-5 UV protection (UPF value) 10 (Unorganized) 52 53 55 54 58 56 Feel Evaluation (Ranking) Hard, rough (worst) softer soft soft Smooth and plump (best quality) Smooth and plump (best quality) Smooth, plump (best quality) As shown in Table 1, the K / S values ​​of all embodiments of the present invention are significantly higher than those of all comparative examples, proving that they have the highest dye utilization and color yield. More importantly, the wet rubbing fastness reached grade 4 or 4-5, far superior to grade 2-3 of comparative example 1. This directly proves that the present invention successfully solved the "ring dyeing" problem, allowing the dye to fully penetrate into the fiber interior, rather than merely adhering to the surface. All embodiments achieved excellent UV resistance (UPF>50), and their effect was comparable to that of comparative example 4, which required additional processes. This proves that the present invention successfully achieved integrated "dyeing-functional finishing," simplifying the process while ensuring functional effectiveness. The fabrics of the embodiments achieved the best hand feel evaluation, thanks to the gentle bio-refining process that did not damage the fibers, and the integrated finishing process that avoided multiple processing steps.

[0038] Furthermore, in terms of energy consumption, the overall energy consumption of Example 1 was 3.2 kW·h / kg fabric, far lower than that of Comparative Example 1 (5.8 kW·h / kg fabric), demonstrating significant energy-saving effect. Regarding process stability, the standard deviation of the K / S value (5 experiments) of Example 1 was 0.15, far lower than that of Comparative Example 3 (0.52), proving its excellent process reproducibility. The main reason for this significant difference lies in the different pH adjustment methods. Comparative Example 3 used manual addition of acid, the timing of which depended on the operator's experience and judgment, making it difficult to perfectly synchronize with the optimal reaction temperature actually reached in the dyeing vat. During the addition process, the high concentration of acid solution instantly entered the system, easily forming localized over-acid areas in the dyeing vat, causing some dyes to fix prematurely or even aggregate, while the pH in other areas had not yet reached the standard, resulting in asynchronous dyeing and fixation, ultimately manifesting as color differences within and between batches. Conversely, the temperature-responsive slow-release fixing agent used in this embodiment of the invention has microcapsule material that only ruptures when a specific temperature is reached, ensuring that the release of the acid agent is highly synchronized with the process temperature point. Furthermore, tens of thousands of microcapsules are evenly distributed in the dye liquor and released simultaneously, achieving instantaneous and uniform diffusion of the acid agent. This allows the pH of the system to smoothly and synchronously transition to the optimal pH fixing range (4.5–5.0), providing a nearly uniform reaction environment for all dye molecules and ensuring that they bind to the fiber at similar rates and degrees. Therefore, it exhibits excellent process stability and color consistency.

[0039] The above data fully demonstrates that the present invention, through the synergistic innovation of multiple technologies such as "irregular fiber + plasma treatment", "bio-enzyme refining", "nano dyes and intelligent slow-release color fixing" and "functional finishing integration", has achieved significant progress in dyeing depth, fastness, energy saving and consumption reduction, production efficiency and product stability. Its comprehensive performance far exceeds that of traditional processes, and it has successfully solved all the technical problems proposed in the background technology.

[0040] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for producing polyester knitted dyed fabric, characterized in that, The production method uses polyester fibers with irregular cross-sections as raw materials, the cross-section of which is multi-lobed or hollow; the production method includes the following sequential steps: S1 fiber pretreatment and spinning: Low-temperature plasma treatment is performed on polyester fibers with irregular cross sections. The treatment power is 200-400W and the treatment time is 2-5min. The treated fibers are then spun into high-count yarns of 50-80S through Siro compact spinning process. S2 knitting: Using the high-count yarn, knitting is done on a fine gauge knitting machine with a gauge of 28 needles / inch or higher to produce single jersey or mesh fabric. S3 Pretreatment: Place the knitted fabric in a treatment solution containing a compound bio-refining enzyme and treat it at 50-55℃ and pH 6.0-7.0 for 30-40 minutes to fully biodegrade and remove spinning oils and waxes; S4 multi-stage gradient staining: (1) Add water and fiber swelling accelerator to the dyeing equipment, adjust the bath ratio to 1:8 to 12, raise the temperature to 65 to 70°C at a rate of 2 to 3°C / min, and run for 10 to 15 minutes; (2) Add the composite nano dye and continue to slowly heat to 75-80℃ at a rate of 0.5-1℃ / min, and keep it at that temperature for 15-20min; (3) Add the temperature-responsive slow-release fixing agent, which releases an acid when the temperature is raised to 90-95°C, automatically adjusting the pH of the system to 4.5-5.0, and keeping it at this temperature for 25-35 minutes; (4) Cool the system temperature to 70-80℃, add the multifunctional compound additive, and run for 15-20 minutes; S5 Post-treatment: After the dyed fabric is washed with cold water, neutralized, soaped, washed with hot water and softened, it is dried and shaped using low-tension airflow, with the soaping temperature range being 95-98℃.

2. The method for producing polyester knitted dyed fabric according to claim 1, characterized in that: In step S3, the composite biorefining enzyme used is a combination of lipase, protease, and alkyl glycoside APG.

3. The method for producing polyester knitted dyed fabric according to claim 1, characterized in that: In step S4, the fiber swelling accelerator is one of benzyl benzoate, o-phenylphenol, or methyl salicylate.

4. The method for producing polyester knitted dyed fabric according to claim 1, characterized in that: In step S4, the composite nano-dye is a nanoscale disperse dye encapsulated with a cationic modifier, wherein the cationic modifier is 3-chloro-2-hydroxypropyltrimethylammonium chloride or glycidyltrimethylammonium chloride.

5. The method for producing polyester knitted dyed fabric according to claim 1, characterized in that: In step S4, the temperature-responsive slow-release fixing agent is a mixture of citric acid and ammonium sulfate encapsulated in polypropylene microcapsules.

6. The method for producing polyester knitted dyed fabric according to claim 1, characterized in that: In step S4, the multifunctional compound additive is composed of rare earth complexing agent and polymer UV-resistant finishing agent in a mass ratio of 1:1 to 3.

7. The method for producing polyester knitted dyed fabric according to claim 6, characterized in that: The rare earth complexing agent is a cerium chloride-fatty alcohol polyoxyethylene ether complex or a lanthanum nitrate-polyethylene glycol complex; the polymeric UV-resistant finishing agent is one of nano-titanium dioxide, UV-P, or UV-327.

8. The method for producing polyester knitted dyed fabric according to claim 1, characterized in that: The multi-stage gradient staining process in step S4 is performed using an ultrasound-assisted device with an ultrasound frequency of 25–40 kHz and a power density of 0.3–0.5 W / cm². 2 .

9. The method for producing polyester knitted dyed fabric according to claim 1, characterized in that: In step S5, an aminoethylaminopropyl polydimethylsiloxane microemulsion is used for softening treatment at a temperature of 40–45°C.

10. A polyester knitted dyed fabric, characterized in that: It is produced using the production method described in any one of claims 1 to 9.