High-color-fastness printing and dyeing process for knitted fabric

Abstract

The invention provides a high-color-fastness printing and dyeing process for knitted fabric, relates to the technical field of textile printing and dyeing, and aims at obviously improving the color fastness to washing and the color fastness to rubbing. The color changing and staining grades in the embodiment are both superior to those of a traditional process, so that the fabric can still keep bright colors after being washed and rubbed for multiple times, the service life of the textile is prolonged, the attractiveness of the textile is improved, for example, the color fastness to washing of a pure cotton fabric in the process reaches grade 4, and the color fastness to washing of the pure cotton fabric in the traditional process is only grade 3; by means of the optimized process, the dye can permeate and be combined into the fibers more sufficiently, and the color depth (K / S value) is remarkably improved. The K / S value of the pure cotton fabric in the embodiment 1 reaches 12.5 and is greatly improved compared with 8.5 of a traditional process, the color of the fabric is brighter and richer, and unnecessary waiting and adjusting links are reduced by accurately controlling process parameters such as optimized pretreatment temperature and time, dyeing temperature and time and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of textile printing and dyeing, and more specifically, particularly relates to a high color fastness printing and dyeing process for knitted fabrics. Background Art

[0002] In the modern textile industry, knitted fabrics are favored for their good elasticity, breathability and comfort, and are widely used in clothing, household goods, etc. However, in the printing and dyeing process of knitted fabrics, how to achieve high color fastness has always been a key issue.

[0003] The traditional knitted fabric printing and dyeing process has many shortcomings. In the pretreatment stage, impurities and grease on the fabric surface are often not effectively removed, which affects the subsequent adsorption and penetration of dyes. In the dyeing process, the temperature, time, bath ratio and pH value are not accurately controlled, resulting in uneven and insufficient dyeing, insufficient color depth and brightness. The color fixation effect is not ideal, so that the combination of dye and fiber is not strong enough, and it is difficult to achieve a high level of color fastness, especially in terms of water resistance and friction resistance.

[0004] In addition, the traditional technology has poor versatility in different types of knitted fabrics (such as pure cotton, polyester-cotton blended, pure polyester, etc.), and it is difficult to optimize the characteristics of various fabrics. At the same time, production efficiency needs to be improved, and the stability and repeatability of the process are difficult to guarantee, resulting in uneven product quality.

[0005] With the improvement of people's living standards and the increasingly stringent requirements for textile quality, the market has put forward higher requirements for the color fastness of knitted fabric printing and dyeing. Not only does it require bright and lasting colors, but it also needs to maintain a good appearance after multiple washings and frictions. Therefore, developing a new knitted fabric high color fastness printing and dyeing process to overcome the defects of traditional processes and meet market demand has become an urgent problem to be solved in the textile industry. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a knitted fabric high color fastness printing and dyeing process to solve the above problems.

[0007] A high color fastness printing and dyeing process for knitted fabrics, comprising the following steps:

[0008] S1: Pretreatment: The knitted fabric is placed in a pretreatment solution and soaked at a temperature of 50°C for 30 minutes. The pretreatment solution contains sodium carbonate at a concentration of 15 g / L.

[0009] S2: dyeing: the pretreated knitted fabric is placed in a dye solution and dyed at a temperature of 80°C for 60 minutes, the dye concentration in the dye solution is 5% (owf), and the bath ratio is 1:15;

[0010] S3: Fixation: The dyed fabric is fixed with a fixing agent at 60°C for 40 minutes with a concentration of 30g / L.

[0011] S4: Washing: Wash the fixed fabric at 40°C for 20 minutes;

[0012] S5: Drying: The washed fabric is dried at a temperature of 80°C for 40 minutes.

[0013] Preferably, the pretreatment liquid further comprises sodium silicate at a concentration of 10 g / L, and the mass ratio of sodium carbonate to sodium silicate is 3:2.

[0014] Preferably, the pH value of the dye solution is controlled at 6.5, and the dye solution is stirred at a speed of 80 r / min during the dyeing process.

[0015] Preferably, the color fixing agent consists of sodium chloride and sodium sulfate in a mass ratio of 2:1.

[0016] Preferably, in the water washing step, the pH value of the water washing liquid is adjusted to 7.0, and the water washing liquid contains acetic acid at a concentration of 5 g / L.

[0017] Preferably, in the drying step, the drying speed is calculated by the following formula: drying speed = (initial weight of fabric - weight of fabric after drying) / drying time, and the drying speed is not less than 10 g / min.

[0018] Preferably, in the dyeing step, the dye uptake rate of the dye is calculated by the following formula: dye uptake rate = (dye solution concentration before dyeing - dye solution concentration after dyeing) / dye solution concentration before dyeing × 100%, and the dye uptake rate is not less than 85%.

[0019] Preferably, the color fastness after color fixation is calculated according to the following formula: color fastness=(fading degree of treated fabric / fading degree of untreated fabric)×100%, and the color fastness is not less than level 4.

[0020] Preferably, during the printing and dyeing process, the tension on the fabric does not exceed 20N.

[0021] Preferably, the heating rate in the dyeing step is 2°C / min, and the cooling rate is 1.5°C / min.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. Significantly improve color fastness: Both the color fastness to washing and the color fastness to rubbing are significantly improved. The discoloration and staining levels in the embodiment are better than those of the traditional process, so that the fabric can still maintain bright colors after multiple washings and rubbings, extending the service life and aesthetics of the textiles. For example, the color fastness to washing of pure cotton fabrics under this process reaches level 4, while the traditional process is only level 3.

[0024] 2. Enhanced color effect: The optimized process can make the dye penetrate and bind more fully into the fiber, and the color depth (K / S value) is significantly improved. For example, the K / S value of the pure cotton fabric in Example 1 reaches 12.5, which is a significant improvement over 8.5 of the traditional process, making the fabric color more vivid and rich.

[0025] 3. Improve production efficiency: By precisely controlling process parameters, such as optimized pretreatment temperature and time, dyeing temperature and time, etc., unnecessary waiting and adjustment links are reduced, thereby shortening the overall production cycle. Compared with traditional processes, more high-quality products can be produced in the same time, reducing production costs and improving the company's market competitiveness.

[0026] 4. Improve product quality stability: Strictly control parameters in each link, such as pH value, bath ratio, stirring speed, etc., to reduce product quality differences caused by process fluctuations, and ensure that each batch of knitted fabrics can achieve high and stable color fastness and color effects to meet customers' consistency requirements.

[0027] 5. Applicable to a wide range of fabrics: Whether it is pure cotton, polyester-cotton blended or pure polyester knitted fabrics, this process can play an effective role and provide excellent printing and dyeing effects, providing strong support for enterprises to cope with diversified market demands and broadening the application field of products.

[0028] 6. The selection and use of auxiliaries are more environmentally friendly, reducing wastewater discharge and environmental pollution, meeting the requirements of modern society for sustainable development. High-quality and high-color-fastness printing and dyeing products can meet customers' pursuit of quality, improve customer satisfaction and loyalty to products, and help companies establish a good brand image. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0030] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0031] As people's requirements for textile quality and appearance continue to increase, the printing and dyeing process of knitted fabrics is particularly important in the textile industry. In particular, the requirements for color fastness are directly related to the quality and service life of the product. The invention proposes a knitted fabric high color fastness printing and dyeing process, which aims to significantly improve the color fastness of knitted fabrics by optimizing the parameters and processing methods of each link, and meet the market demand for high-quality printing and dyeing products.

[0032] This printing and dyeing process is mainly based on the synergistic effect of chemical treatment and physical action. Pretreatment is used to remove impurities and grease on the surface of the fabric to create good conditions for the uniform adsorption and penetration of the dye. During the dyeing process, parameters such as temperature, time, bath ratio and pH value are precisely controlled to ensure that the dye is fully dyed and combined with the fiber. The color fixing treatment further enhances the chemical bond between the dye and the fiber and improves color fastness. The washing and drying steps remove unbound dyes and auxiliaries to achieve the ideal color effect and stability of the fabric.

[0033] Select a variety of common knitted fabrics, such as pure cotton, polyester-cotton blended, pure polyester, etc. Each fabric has different tissue structures and fiber characteristics. Prepare a variety of reactive dyes, direct dyes and acid dyes to meet the printing and dyeing needs of different colors and fabrics, various auxiliaries, including alkali agents and penetrants in pretreatment liquid, leveling agents and accelerators in the dyeing process, and cationic compounds in fixing agents, etc.;

[0034] Among the experimental equipment, the high-temperature dyeing machine can accurately control the temperature, time and stirring speed, the electronic balance is used to accurately weigh the amount of dyes and auxiliaries, the pH meter is used to measure the pH value of the dye solution and pretreatment solution, the colorimeter is used to measure the color change and color fastness of the fabric, and the tensile testing machine is used to test the tension changes of the fabric during the printing and dyeing process.

[0035] A series of experiments were designed to pretreat knitted fabrics at different temperatures (such as 40℃, 50℃, and 60℃), and the treatment time was set to 20 minutes, 30 minutes, and 40 minutes respectively. By comparing the surface cleanliness, fiber wettability, and subsequent dyeing effect of the treated fabrics, the optimal pretreatment temperature was determined to be 50℃ and the time was 30 minutes. Different dyeing temperatures (such as 70℃, 80℃, and 90℃) and dyeing times (such as 40 minutes, 60 minutes, and 80 minutes) were set for different dye types and fabric materials. The color depth and uniformity after dyeing were measured using a colorimeter. The dyeing effects under different parameter combinations were evaluated, and the optimal dyeing temperature was determined to be 80℃ and the time was 60 minutes. The fixing temperature (such as 50℃, 60℃, and 70℃) and the fixing time (such as 40 minutes, 60 minutes, and 80 minutes) were changed. The color fastness of the fabric after fixing was observed, and color fastness tests were carried out according to relevant standards, such as color fastness to washing and color fastness to rubbing, etc. The optimal fixing temperature was determined to be 60°C and the fixing time was 40 minutes. The bath ratio was adjusted (such as 1:10, 1:15, 1:20) to study its effect on dye uptake and dyeing uniformity. The residual amount of dye in the dye liquor was determined by chemical analysis, the dye uptake was calculated, and the appropriate bath ratio was determined to be 1:15 in combination with the appearance quality of the fabric. During the dyeing process, the pH value of the dye liquor was controlled in different ranges (such as 5.0, 6.0, 7.0), the color effect and color fastness were observed, the pH value was accurately adjusted and monitored using a pH meter, and the optimal pH range was determined to be 6.5 through experimental data.

[0036] In order to more intuitively demonstrate the effect of the printing and dyeing process of the present invention, a number of specific embodiments are given below and compared with the traditional printing and dyeing process.

[0037] Example 1, printing and dyeing of pure cotton knitted fabrics:

[0038] Select pure cotton knitted fabric with a weight of 200g / m 2, width is 1.5m, pretreatment solution formula: sodium carbonate 15g / L, penetrant JFC5g / L, treatment conditions: temperature 50℃, time 30 minutes, dye: reactive red X-3B, dye solution formula: dye concentration 5% (owf), leveling agent 1g / L, accelerator sodium sulfate 20g / L, dyeing conditions: temperature 80℃, time 60 minutes, bath ratio 1:15, pH value 6.5, stirring speed 80r / min, color fixing agent formula: sodium chloride 15g / L, sodium sulfate 10g / L, color fixing conditions: temperature 60℃, time 40 minutes, washing temperature 40℃, time 20 minutes, washing liquid pH value 7.0, containing 5g / L acetic acid, drying temperature 80℃, time 40 minutes, color depth (K / S value): measured by colorimeter, K / S value is 12.5, color fastness to washing: tested in accordance with GB / T3921-2008 standard, the color change grade is 4, the staining grade is 4, color fastness to rubbing: tested in accordance with GB / T3920-2008 standard, the dry friction grade is 4, and the wet friction grade is 3.

[0039] Example 2, printing and dyeing of polyester-cotton blended knitted fabric:

[0040] Select polyester-cotton blended knitted fabric (polyester / cotton ratio is 65 / 35), weight is 180g / m 2 , width is 1.6m, pretreatment solution formula: sodium carbonate 10g / L, sodium silicate 8g / L, penetrant JFC3g / L, treatment conditions: temperature 55℃, time 25 minutes, dye: disperse dye red FB, dye solution formula: dye concentration 4% (owf), leveling agent 0.8g / L, dyeing conditions: temperature 130℃, time 50 minutes, bath ratio 1:12, pH value 5.5, stirring speed 70r / min, color fixing agent formula: cationic color fixing agent DT-2525g / L, color fixing conditions: temperature 80℃ , time 35 minutes, washing temperature 45℃, time 15 minutes, washing liquid pH value 6.5, containing 3g / L sodium dihydrogen phosphate, drying temperature 90℃, time 30 minutes, color depth (K / S value): measured by colorimeter, K / S value is 10.8, color fastness to washing: tested in accordance with GB / T3921-2008 standard, the color change grade is 4, the staining grade is 3-4, color fastness to rubbing: tested in accordance with GB / T3920-2008 standard, the dry friction grade is 4, and the wet friction grade is 3.

[0041] Example 3, printing and dyeing of pure polyester knitted fabrics:

[0042] Select pure polyester knitted fabric with a weight of 150g / m 2, width is 1.8m, pretreatment solution formula: sodium carbonate 8g / L, penetrant JFC2g / L, treatment conditions: temperature 45℃, time 20 minutes, dye: acid dye red G, dye solution formula: dye concentration 3% (owf), leveling agent 0.5g / L, accelerator sodium acetate 15g / L, dyeing conditions: temperature 100℃, time 45 minutes, bath ratio 1:10, pH value 4.5, stirring speed 60r / min, color fixing agent formula: tannic acid 10g / L, potassium aluminum sulfate 8g / L, color fixing conditions: temperature 70 ℃, time 30 minutes, washing temperature 35℃, time 10 minutes, washing liquid pH value 5.0, containing citric acid 4g / L, drying temperature 70℃, time 25 minutes, color depth (K / S value): measured by colorimeter, K / S value is 8.5, color fastness to washing: tested in accordance with GB / T3921-2008 standard, the color change grade is 3-4, the staining grade is 3, color fastness to rubbing: tested in accordance with GB / T3920-2008 standard, the dry friction grade is 3-4, and the wet friction grade is 2-3.

[0043] Comparative Example, Traditional Printing and Dyeing Process:

[0044] The fabrics were prepared as pure cotton, polyester-cotton blended and pure polyester knitted fabrics as in Examples 1-3, the pretreatment solution formula was: 8 g / L sodium carbonate, the penetrant JFC 2 g / L, the treatment conditions were: temperature 40°C, time 20 minutes, the dye and dye solution formula were the same as in the example, the dyeing conditions were: the temperature and time were set according to the dye type, the bath ratio was 1:8, the pH value was not precisely controlled, the stirring speed was 50 r / min, the fixing agent and fixing conditions were set by conventional methods, the washing temperature and time were set conventionally, the drying temperature and time were set conventionally, and the color depth (K / S value) was measured using a colorimeter, the K / S value of the pure cotton fabric was 8.5, and the K / S value of the polyester-cotton blended fabric was 8.5. / S value is 7.2, K / S value of pure polyester fabric is 5.8, color fastness to washing: tested according to GB / T3921-2008 standard, the color change level of pure cotton fabric is 3, and the color staining level is 3; the color change level of polyester-cotton blended fabric is 3, and the color staining level is 2-3; the color change level of pure polyester fabric is 2-3, and the color staining level is 2, color fastness to rubbing: tested according to GB / T3920-2008 standard, the dry friction level of pure cotton fabric is 3, and the wet friction level is 2; the dry friction level of polyester-cotton blended fabric is 3, and the wet friction level is 2; the dry friction level of pure polyester fabric is 2-3, and the wet friction level is 1-2.

[0045] The experimental data of Examples 1-3 and Comparative Examples are organized into a table as follows:

[0046]

[0047] It can be seen from the table data that the printing and dyeing process of the present invention is significantly superior to the traditional printing and dyeing process in terms of color depth and color fastness, whether it is pure cotton, polyester-cotton blended or pure polyester knitted fabric. The specific analysis is as follows:

[0048] 1. The K / S values ​​of Examples 1-3 are all higher than those of the comparative example, indicating that the process of the present invention can make the dye penetrate and bind more fully into the fiber, thereby obtaining a brighter and richer color effect;

[0049] 2. In terms of discoloration and staining levels, Examples 1-3 all reached a relatively high level, which was significantly better than the comparative example. This shows that the color fixation treatment and washing steps of this process can effectively remove unbound dyes, improve the binding stability between dyes and fibers, and reduce color shedding during washing and staining of adjacent fabrics;

[0050] 3. In terms of dry friction and wet friction levels, the examples also show better performance, which is because the process of the present invention optimizes the dyeing and fixing conditions, and enhances the adhesion of the dye on the fiber surface and the friction resistance.

[0051] The high color fastness printing and dyeing process for knitted fabrics of the present invention significantly improves the color fastness and color effect of knitted fabrics by optimizing the pretreatment, dyeing, color fixing, washing and drying processes. The experimental data of multiple embodiments show that the process has excellent performance on different types of knitted fabrics and is superior to traditional printing and dyeing processes. The application in actual production has also achieved good results and has a high value for promotion and application. In the future, with the continuous advancement of technology and changes in market demand, the process can be further optimized and improved to adapt to a wider range of application scenarios and higher quality requirements.

[0052] Both the color fastness to washing and the color fastness to rubbing are significantly improved. The discoloration and staining levels in the embodiment are better than those of the traditional process, so that the fabric can still maintain bright colors after multiple washings and rubbings, extending the service life and aesthetics of the textiles. For example, the color fastness to washing of the pure cotton fabric under this process reaches level 4, while the traditional process is only level 3. The optimized process can make the dye penetrate and bind to the inside of the fiber more fully, and the color depth (K / S value) is significantly improved. For example, the K / S value of the pure cotton fabric in Example 1 reaches 12.5, which is a significant improvement over 8.5 of the traditional process, making the fabric color more vivid and rich. By precisely controlling process parameters, such as optimized pretreatment temperature and time, dyeing temperature and time, etc., unnecessary waiting and adjustment links are reduced, thereby shortening the overall production cycle. Compared with traditional processes, more high-quality products can be produced in the same time, reducing production costs and improving the company's market competitiveness. Strict control of parameters in each link, such as pH value, bath ratio, stirring speed, etc., reduces product quality differences caused by process fluctuations, ensuring that each batch of knitted fabrics can achieve high and stable color fastness and color effects to meet customer consistency requirements. Whether it is knitted fabrics of different materials such as pure cotton, polyester-cotton blended or pure polyester, this process can effectively play a role and provide excellent printing and dyeing effects, providing strong support for enterprises to cope with diverse market demands and broadening the application areas of products.

[0053] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A high color fastness printing and dyeing process for knitted fabrics, characterized in that: The following steps are involved: S1： Pretreatment: The knitted fabric is placed in a pretreatment solution and soaked at a temperature of 50°C for 30 minutes. The pretreatment solution contains sodium carbonate at a concentration of 15g / L. S2: dyeing: the pretreated knitted fabric is placed in a dye solution and dyed at a temperature of 80°C for 60 minutes, the dye concentration in the dye solution is 5% (owf), and the bath ratio is 1:15; S3: Fixation: The dyed fabric is fixed with a fixing agent at 60°C for 40 minutes with a concentration of 30g / L. S4: Washing: Wash the fixed fabric at 40°C for 20 minutes; S5: Drying: The washed fabric is dried at a temperature of 80°C for 40 minutes.

2. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: The pretreatment liquid also contains sodium silicate with a concentration of 10 g / L, and the mass ratio of sodium carbonate to sodium silicate is 3:

2.

3. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: The pH value of the dye solution was controlled at 6.5, and the solution was stirred at a speed of 80 r / min during the dyeing process.

4. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: The color fixing agent is composed of sodium chloride and sodium sulfate in a mass ratio of 2:

1.

5. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: In the water washing step, the pH value of the water washing liquid is adjusted to 7.0, and the water washing liquid contains acetic acid with a concentration of 5 g / L.

6. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: In the drying step, the drying speed is calculated by the following formula: drying speed = (initial weight of fabric - weight of fabric after drying) / drying time, and the drying speed is not less than 10 g / min.

7. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: In the dyeing step, the dye uptake rate of the dye is calculated by the following formula: dye uptake rate = (dye solution concentration before dyeing - dye solution concentration after dyeing) / dye solution concentration before dyeing × 100%, and the dye uptake rate is not less than 85%.

8. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: The color fastness after color fixation is calculated according to the following formula: color fastness=(fading degree of treated fabric / fading degree of untreated fabric)×100%, and the color fastness is not less than level 4.

9. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: During the printing and dyeing process, the tension on the fabric does not exceed 20N.

10. The high color fastness printing and dyeing process for knitted fabrics according to claim 1, characterized in that: The heating rate in the dyeing step is 2°C / min, and the cooling rate is 1.5°C / min.

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