A knitting fabric dyeing and finishing process

Abstract

This invention provides a dyeing and finishing process for knitted fabrics. By controlling two temperature stages sequentially in the same treatment bath, the three processes of desizing, scouring, and bleaching are completed continuously in the same equipment and bath, eliminating the need for the multi-step intermittent operations of desizing followed by scouring, bleaching, and subsequent discharge as in traditional processes. This design significantly reduces equipment occupancy time and operational steps in the pretreatment stage, decreases the number of times fabric enters and exits the bath, and effectively improves the operating efficiency of the production line. Furthermore, steps S102 and S103 divide the processing into two temperature stages: the two-stage variable temperature design allows enzyme treatment and oxygen bleaching to be completed in succession in the same bath, ensuring both the efficient action of the biological enzymes and the full realization of the bleaching effect. The maximum temperature of the entire processing is controlled below 85℃, which is significantly lower than the 98℃ to 100℃ of traditional processes, and eliminates the need for prolonged high-temperature insulation.

Description

Technical Field

[0001] This invention relates to the field of fabric processing, and in particular to a dyeing and finishing process for knitted fabrics. Background Technology

[0002] Knitted fabrics are widely used in clothing, home textiles and other fields due to their good elasticity, softness and comfort. Knitted fabrics, represented by cotton, regenerated cellulose fibers and their blends, usually require a series of dyeing and finishing processes after weaving, such as pretreatment, dyeing, color fixing and finishing, to remove natural impurities and weaving sizing on the fibers and to give the fabric the desired color, hand feel and wearing performance.

[0003] Currently, the traditional dyeing and finishing process for knitted fabrics typically includes the following main steps: First, pretreatment (desizing, scouring, and bleaching) is carried out using a high-temperature, strong-alkali process. The treatment temperature generally needs to reach 98℃ to 100℃, and large amounts of chemicals such as caustic soda and hydrogen peroxide are used. Second, reactive dyeing is carried out using immersion dyeing or pad dyeing methods. The dyeing temperature is mostly 80℃ to 98℃, and the dyeing time is as long as 60 to 90 minutes. Large amounts of dyeing accelerators and color-fixing auxiliaries such as sodium sulfate and soda ash are added. Third, after dyeing, color-fixing treatment is usually carried out using a high-temperature steaming method at 102℃ to 105℃. Finally, the finished product is obtained after high-temperature soaping (95℃ to 98℃), washing, softening, and drying.

[0004] However, the above-mentioned traditional dyeing and finishing processes for knitted fabrics have the following problems in practical applications: 1. Pretreatment, dyeing, color fixing and soaping processes all need to be carried out under high temperature conditions, resulting in high steam consumption and high overall energy consumption in the processing. 2. Prolonged high-temperature and strong-alkali treatment can cause a certain degree of degradation and damage to cellulose fibers such as cotton, viscose, and modal, resulting in high fabric weight loss, reduced strength, and a rough and stiff feel, which affects the feel and durability of the final product. Summary of the Invention

[0005] (a) Technical problems to be solved To address the aforementioned problems in the prior art, this invention provides a dyeing and finishing process for knitted fabrics.

[0006] (II) Technical Solution To achieve the above objectives, the main technical solutions adopted by the present invention include: A dyeing and finishing process for knitted fabrics includes the following steps: Step S1, Pre-treatment: The knitted fabric to be treated is simultaneously desized, scouring and bleached in the same treatment bath; Step S2, dyeing treatment: An ultrasonic generator is integrated into the overflow dyeing machine or the package dyeing machine. Ultrasonic-assisted dyeing is performed directly on the wet cloth after pretreatment. Ultrasonic waves are continuously applied during the dye liquor circulation process. Step S3, color fixing treatment: The ultrasonically dyed fabric is directly immersed in the color fixing alkali solution through a uniform padding machine without washing, and then rolled up and stacked. It is then slowly rotated and stacked at room temperature for a certain period of time to complete the color fixing.

[0007] Preferably, the desizing, refining, and bleaching processes in step S1 are achieved through the following steps: Step S101: Arrange the knitted fabric to be treated in the treatment solution, which contains a compound biological enzyme preparation, an oil remover, hydrogen peroxide and an oxygen bleaching stabilizer, and control the bath ratio to be 1:8 to 1:10. Step S102: At the first stage processing temperature, the knitted fabric is processed for a first time period; Step S103: After completing the processing in the first time period, raise the processing temperature to the second stage processing temperature and continue the processing in the second time period. Step S104: Wash the pre-treated knitted fabric with hot water, warm water and cold water in sequence.

[0008] Preferably, the first stage processing temperature in step S102 is 50°C to 60°C, and the first time period is 20 to 40 minutes.

[0009] Preferably, the second stage processing temperature in step S103 is 75°C to 85°C, and the second time period is 10 to 20 minutes.

[0010] Preferably, the compound biological enzyme preparation uses refined enzyme KDN-301.

[0011] Preferably, the staining process in step S2 is achieved through the following steps: Step S201: The pretreated wet knitted blank is placed in a dyeing device, which is equipped with an ultrasonic generator with a frequency of 20 kHz to 40 kHz. Step S202: Add dye solution to the dyeing equipment, the dye solution containing reactive dye and a first part of dyeing salt, control the dyeing bath ratio to be 1:6 to 1:8, and the starting temperature to be 35°C to 45°C; Step S203: Increase the temperature of the dye liquor to 60°C to 70°C at a heating rate of 0.8°C / min to 1.5°C / min, and continuously turn on the ultrasonic generator during the heating process and after reaching the dyeing temperature to apply ultrasonic waves to the dye liquor and the knitted fabric. Step S204: When the temperature is raised to 48°C to 52°C, add the second part of the staining-promoting salt to the dyeing solution; Step S205: After the dye solution temperature reaches 60°C to 70°C, add the alkali to the dye solution at least twice, with an interval of 8 to 15 minutes between each addition of the alkali, and continue dyeing for 15 to 30 minutes after adding all the alkali.

[0012] Preferably, in step S202, the amount of reactive dye used is 0.5% to 4% of the fabric weight, and the amount of the first part of the dyeing salt used is 50% to 70% of the total amount of dyeing salt used.

[0013] Preferably, the dyeing salt is sodium sulfate, and its total dosage is 20 g / L to 40 g / L.

[0014] Preferably, the color-fixing treatment is achieved through the following steps: Step S301: The knitted fabric after ultrasonic-assisted dyeing is fed directly into the uniform rolling mill in a flat, wet state without being washed. Step S302: The knitted fabric is subjected to padding treatment by the uniform padding machine, so that it is impregnated with the fixing alkali solution, and the pick-up rate is controlled to be 90% to 105%; Step S303: Roll the knitted fabric after it has been impregnated with the color-fixing alkali solution into a roll and wrap the roll with a sealing material; Step S304: Place the wrapped roll on a rotating device, rotate it at low speed at room temperature and stack it for 6 to 12 hours to complete the solid-phase color fixation reaction between the reactive dye and the fiber. Step S305: After the color-fixing reaction is completed, the knitted fabric is sequentially washed with cold water, warm water, soap, warm water, and cold water to remove unfixed floating dye and residual chemicals.

[0015] (III) Beneficial Effects The beneficial effects of this invention are as follows: 1. The maximum temperature of pretreatment is reduced from the traditional 98-100℃ to 55-80℃, the maximum temperature of dyeing is reduced from the traditional 80-98℃ to 60-70℃, and the color fixing process is replaced by room temperature stacking instead of the traditional 102-105℃ high-temperature steaming. The entire process has almost no high-temperature steam consumption, which greatly reduces energy consumption. 2. From pretreatment to dyeing and from dyeing to color fixing, a continuous "wet-to-wet" processing method is adopted, which eliminates the multiple intermediate steps such as repeated washing, dehydration, drying and rewetting in the traditional process, resulting in significant water-saving efficiency; 3. Using compound biological enzyme preparations to replace caustic soda for pretreatment greatly reduces the amount of dyeing salt used, and the low-temperature online mixing of the fixing alkali solution reduces dye hydrolysis and chemical waste. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the steps involved in the dyeing and finishing process of a knitted fabric. Detailed Implementation

[0017] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] This invention provides a dyeing and finishing process for knitted fabrics, comprising the following steps: Step S1, Pre-treatment: The knitted fabric to be treated is simultaneously desized, scouring and bleached in the same treatment bath; Step S2, dyeing treatment: An ultrasonic generator is integrated into the overflow dyeing machine or the package dyeing machine. Ultrasonic-assisted dyeing is performed directly on the wet cloth after pretreatment. Ultrasonic waves are continuously applied during the dye liquor circulation process. Step S3, color fixing treatment: The ultrasonically dyed fabric is directly immersed in the color fixing alkali solution through a uniform padding machine without washing, and then rolled up and stacked. It is then slowly rotated and stacked at room temperature for a certain period of time to complete the color fixing.

[0019] In this embodiment, the desizing, refining, and bleaching processes in step S1 are achieved through the following steps: Step S101: Arrange the knitted fabric to be treated in the treatment solution, which contains a compound biological enzyme preparation, an oil remover, hydrogen peroxide and an oxygen bleaching stabilizer, and control the bath ratio to be 1:8 to 1:10. Step S102: At the first stage processing temperature, the knitted fabric is processed for a first time period; Step S103: After completing the processing in the first time period, raise the processing temperature to the second stage processing temperature and continue the processing in the second time period. Step S104: Wash the pre-treated knitted fabric with hot water, warm water and cold water in sequence.

[0020] In the reverse embodiment, the first stage processing temperature in step S102 is 50°C to 60°C, and the first time period is 20 to 40 minutes.

[0021] In step S103, the second stage processing temperature is 75°C to 85°C, and the second time period is 10 to 20 minutes.

[0022] The compound biological enzyme preparation uses refined enzyme KDN-301; In use, step S1 controls two temperature stages sequentially within the same treatment bath, allowing the three processes of desizing, scouring, and bleaching to be completed continuously in the same equipment and bath, eliminating the need for the multi-step intermittent operations of desizing followed by discharge, re-scouring, and re-bleaching as in traditional processes. This design significantly reduces equipment occupancy time and operational steps in the pretreatment section, decreases the number of times fabrics enter and exit the bath, and effectively improves the operating efficiency of the production line. Furthermore, steps S102 and S103 divide the treatment process into two temperature stages: the two-stage variable temperature design allows enzyme treatment and oxygen bleaching to be completed in succession within the same bath, ensuring both the efficient action of the biological enzymes and the full realization of the bleaching effect. The maximum temperature of the entire treatment process is controlled below 85℃, significantly lower than the 98℃ to 100℃ of traditional processes, and eliminates the need for prolonged high-temperature insulation.

[0023] In this embodiment, the staining process in step S2 is achieved through the following steps: Step S201: The pretreated wet knitted blank is placed in a dyeing device, which is equipped with an ultrasonic generator with a frequency of 20 kHz to 40 kHz. Step S202: Add dye solution to the dyeing equipment, the dye solution containing reactive dye and a first part of dyeing salt, control the dyeing bath ratio to be 1:6 to 1:8, and the starting temperature to be 35°C to 45°C; Step S203: Increase the temperature of the dye liquor to 60°C to 70°C at a heating rate of 0.8°C / min to 1.5°C / min, and continuously turn on the ultrasonic generator during the heating process and after reaching the dyeing temperature to apply ultrasonic waves to the dye liquor and the knitted fabric. Step S204: When the temperature is raised to 48°C to 52°C, add the second part of the staining-promoting salt to the dyeing solution; Step S205: After the dye solution temperature reaches 60°C to 70°C, add the alkali to the dye solution at least twice, with an interval of 8 to 15 minutes between each addition of the alkali, and continue dyeing for 15 to 30 minutes after adding all the alkali.

[0024] In this embodiment, the amount of reactive dye used in step S202 is 0.5% to 4% of the fabric weight, and the amount of the first part of the dyeing salt is 50% to 70% of the total amount of dyeing salt.

[0025] The dyeing salt is sodium sulfate, and its total dosage is 20 g / L to 40 g / L; In operation, during steps S201 to S203, the dyeing equipment integrates an ultrasonic generator with a frequency of 20 kHz to 40 kHz. During the dye liquor circulation process, ultrasonic waves are continuously applied to the dye liquor and fabric. The cavitation effect generated by the ultrasound effectively breaks down dye molecule aggregates, accelerating the adsorption of dye molecules onto the fiber surface and their diffusion into the fiber interior. Furthermore, step S203 controls the maximum dyeing temperature to 60℃ to 70℃, significantly lower than the 80℃ to 98℃ of traditional reactive dye dyeing processes. This reduction in dyeing temperature directly decreases steam consumption, reducing the overall energy consumption of the dyeing process by approximately 35% to 55%. Simultaneously, the pretreated wet fabric enters the dyeing process directly without drying (step S201), avoiding energy consumption in the intermediate drying stage and further enhancing the overall energy-saving effect.

[0026] In this embodiment, the color-fixing process is achieved through the following steps: Step S301: The knitted fabric after ultrasonic-assisted dyeing is fed directly into the uniform rolling mill in a flat, wet state without being washed. Step S302: The knitted fabric is subjected to padding treatment by the uniform padding machine, so that it is impregnated with the fixing alkali solution, and the pick-up rate is controlled to be 90% to 105%; Step S303: Roll the knitted fabric after it has been impregnated with the color-fixing alkali solution into a roll and wrap the roll with a sealing material; Step S304: Place the wrapped roll on a rotating device, rotate it at low speed at room temperature and stack it for 6 to 12 hours to complete the solid-phase color fixation reaction between the reactive dye and the fiber. Step S305: After the color-fixing reaction is completed, the knitted fabric is washed in cold water, warm water, soap, warm water and cold water in sequence to remove unfixed floating color and residual chemicals. In use, step S304 involves piling the fabric after padding with the alkali solution at room temperature for 6 to 12 hours to complete the color-fixing reaction. This completely replaces the high-temperature steam color-fixing step of 102°C to 105°C in the traditional process, reducing steam consumption in the color-fixing process to near zero. This step achieves an energy saving effect of over 90%, making it one of the most significant energy-saving and consumption-reducing key steps in the entire process. Furthermore, step S301 involves directly feeding the fabric after ultrasonic dyeing into the uniform padding machine for padding with the alkali solution in a flat, wet state without washing or drying. This design achieves a seamless "wet-to-wet" connection between the dyeing and color-fixing processes, eliminating the multiple intermediate steps required in the traditional process, such as washing to remove excess color, drying, and padding with alkali solution after dyeing. This significantly shortens the process, saves water and energy, and improves production efficiency.

[0027] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention's specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

[0028] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A dyeing and finishing process for knitted fabrics, characterized in that, Includes the following steps: Step S1, Pre-treatment: The knitted fabric to be treated is simultaneously desized, scouring and bleached in the same treatment bath; Step S2, dyeing treatment: An ultrasonic generator is integrated into the overflow dyeing machine or the package dyeing machine. Ultrasonic-assisted dyeing is performed directly on the wet cloth after pretreatment. Ultrasonic waves are continuously applied during the dye liquor circulation process. Step S3, color fixing treatment: The ultrasonically dyed fabric is directly immersed in the color fixing alkali solution through a uniform padding machine without washing, and then rolled up and stacked. It is then slowly rotated and stacked at room temperature for a certain period of time to complete the color fixing.

2. The dyeing and finishing process for knitted fabrics according to claim 1, characterized in that, The desizing, scouring, and bleaching processes in step S1 are achieved through the following steps: Step S101: Arrange the knitted fabric to be treated in the treatment solution, which contains a compound biological enzyme preparation, an oil remover, hydrogen peroxide and an oxygen bleaching stabilizer, and control the bath ratio to be 1:8 to 1:

10. Step S102: At the first stage processing temperature, the knitted fabric is processed for a first time period; Step S103: After completing the processing in the first time period, raise the processing temperature to the second stage processing temperature and continue the processing in the second time period. Step S104: Wash the pre-treated knitted fabric with hot water, warm water and cold water in sequence.

3. The dyeing and finishing process for knitted fabrics according to claim 2, characterized in that, The first stage processing temperature in step S102 is 50°C to 60°C, and the first time period is 20 to 40 minutes.

4. The dyeing and finishing process for knitted fabrics according to claim 2, characterized in that, The second stage processing temperature in step S103 is 75°C to 85°C, and the second time period is 10 to 20 minutes.

5. The dyeing and finishing process for knitted fabrics according to claim 2, characterized in that, The compound biological enzyme preparation uses refined enzyme KDN-301.

6. The dyeing and finishing process for knitted fabrics according to claim 1, characterized in that, The staining process in step S2 is achieved through the following steps: Step S201: The pretreated wet knitted blank is placed in a dyeing device, which is equipped with an ultrasonic generator with a frequency of 20 kHz to 40 kHz. Step S202: Add dye solution to the dyeing equipment, the dye solution containing reactive dye and a first part of dyeing salt, control the dyeing bath ratio to be 1:6 to 1:8, and the starting temperature to be 35°C to 45°C; Step S203: Increase the temperature of the dye liquor to 60°C to 70°C at a heating rate of 0.8°C / min to 1.5°C / min, and continuously turn on the ultrasonic generator during the heating process and after reaching the dyeing temperature to apply ultrasonic waves to the dye liquor and the knitted fabric. Step S204: When the temperature is raised to 48°C to 52°C, add the second part of the staining-promoting salt to the dyeing solution; Step S205: After the dye solution temperature reaches 60°C to 70°C, add the alkali to the dye solution at least twice, with an interval of 8 to 15 minutes between each addition of the alkali, and continue dyeing for 15 to 30 minutes after adding all the alkali.

7. The dyeing and finishing process for knitted fabrics according to claim 6, characterized in that, In step S202, the amount of reactive dye used is 0.5% to 4% of the fabric weight, and the amount of the first part of the dyeing salt used is 50% to 70% of the total amount of dyeing salt used.

8. The dyeing and finishing process for knitted fabrics according to claim 6, characterized in that, The dyeing salt is sodium sulfate, and its total dosage is 20 g / L to 40 g / L.

9. The dyeing and finishing process for knitted fabrics according to claim 1, characterized in that, The color-fixing process is achieved through the following steps: Step S301: The knitted fabric after ultrasonic-assisted dyeing is fed directly into the uniform rolling mill in a flat, wet state without being washed. Step S302: The knitted fabric is subjected to padding treatment by the uniform padding machine, so that it is impregnated with the fixing alkali solution, and the pick-up rate is controlled to be 90% to 105%; Step S303: Roll the knitted fabric after it has been impregnated with the color-fixing alkali solution into a roll and wrap the roll with a sealing material; Step S304: Place the wrapped roll on a rotating device, rotate it at low speed at room temperature and stack it for 6 to 12 hours to complete the solid-phase color fixation reaction between the reactive dye and the fiber. Step S305: After the color-fixing reaction is completed, the knitted fabric is sequentially washed with cold water, warm water, soap, warm water, and cold water to remove unfixed floating dye and residual chemicals.

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