A method for improving color fastness of medium-dark polyester fabric

Abstract

The application discloses a kind of middle dark color polyester fabric color fastness promotion dyeing method, comprising: selecting SFN type high washing color fastness dye;With emulsifying refining agent dyeing pretreatment using memory fiber dyeing auxiliary agent;Dyeing is carried out at 125-130 DEG C;First soaping is carried out at 75-85 DEG C;Heat setting is carried out at 175-185 DEG C temperature;Second soaping;Heat setting is carried out at 120-130 DEG C temperature.Rational dye type and proportion can be selected to stabilize the color change of subsequent soaping;Memory fiber dyeing auxiliary agent and emulsifier are used in the same bath before dyeing, and fabric surface permeability is increased during scouring.Through twice soaping and twice setting at different temperatures, high-temperature setting fully releases the floating color on the surface of the fiber to the surface of the fiber, while eliminating the internal stress of the fabric and eliminating wrinkles.Secondly, the internal stress of the fabric generated in the wet heat environment during soaping is released by reducing the setting temperature, and finally a middle dark color fabric with high color fastness is obtained.

Description

Technical Field

[0001] This invention relates to a dyeing method for improving the color fastness of medium-dark polyester fabrics, belonging to the technical field of dyeing methods for medium-dark polyester fabrics. Background Technology

[0002] In the current international environment, textile enterprises face equally urgent challenges. Improving product quality, enhancing industry competitiveness, increasing investment in research and development, and strengthening the development of high-quality fabrics are essential steps for the textile industry. The future development of the textile industry faces numerous opportunities and challenges, requiring accelerated progress towards intelligent manufacturing, energy conservation and environmental protection, high-end products, and globalization to achieve sustainable development. Only by staying at the forefront of market and technological development and continuously innovating and upgrading can enterprises remain invincible in the fiercely competitive market.

[0003] In recent years, the requirements for dyeing and printing orders have become increasingly stringent. Customers are paying more attention to the quality of finished products, including various physical and chemical parameters and color fastness. Furthermore, they have broader requirements for special fastness properties such as light fastness and chlorination fastness. Spring spun fabrics have undergone a product redesign in the textile industry. Besides using matte yarn raw materials and innovating weaving processes, they have also extended their dyeing and finishing processes, increasing density, making the hand feel softer, and expanding functionality. However, because their warp and weft yarns are usually composed of elastic yarns, color fastness is often poor when the color is darker. Similarly, fabrics made of twisted filament weaves are prone to this problem. Due to the dyeing mechanism of disperse dyes, the dye and fiber are bound by physical bonding and van der Waals forces, resulting in a weaker bond. Color fastness is typically only grade 3 or 3-4. In subsequent use, washing, and other practical situations, the disperse dyes detach, causing discoloration and fading, significantly affecting the usability and compromising product quality. Improving the fastness of medium and dark colors when dyeing polyester with disperse dyes requires urgent market demand and has practical significance.

[0004] For medium- and dark-colored elastic yarn products (such as spring spun yarn) and filament products (such as wavy yarn), improving the color fastness of the finished product further enhances product quality and increases the invoiced unit price. An improvement of approximately one grade in color fastness can increase the invoiced unit price by about 20%-25%, translating into more direct economic benefits. Meanwhile, customers currently have high requirements for various fastness properties of finished products. The challenge is to improve the washing fastness, acid perspiration fastness, alkaline perspiration fastness, dry rubbing fastness, and wet rubbing fastness of medium- and dark-colored products to grade 4 or even better, reaching leading domestic and international levels. Summary of the Invention

[0005] The purpose of this invention is to provide a dyeing method for improving the color fastness of medium-dark polyester fabrics, which can improve the color fastness of polyester fabrics.

[0006] To solve the above-mentioned technical problems, the objective of this invention is achieved as follows: The present invention relates to a dyeing method for improving the color fastness of medium-dark polyester fabrics, comprising the following steps: (I) Selection of dyes: Select SFN type high wash fastness dyes, wherein Disperse Red SFN accounts for less than 15% of the total dye weight, Disperse Yellow SFN accounts for 25%-35% of the total dye weight, and the remainder is Disperse Blue SFN; (II) Pre-dyeing treatment: The polyester fabric is placed in the pre-dyeing treatment solution and heated to 115-120℃ for 25-35 minutes; the pre-dyeing treatment solution contains 1-1.5 g / L of memory fiber dyeing auxiliary agent and 0.5-1 g / L of emulsifying refining agent. (III) Dyeing: The pre-treated polyester fabric is placed in the dye bath at 45-50℃, and the temperature is raised to 125-130℃ and kept at that temperature for 35-45 minutes. The dye bath contains SFN type high wash fastness dye, leveling agent and stabilizer in a set amount, and the pH value of the dye bath is controlled to be 4.0-4.5. (iv) First soaping: The dyed polyester fabric is washed with the first soaping solution at 75-85℃; the first soaping solution includes sodium hydroxide and sodium hydrosulfite. (v) First heat setting: The polyester fabric after the first soaping is heat set at a temperature of 175-185℃. (vi) Second soaping: The polyester fabric that has undergone the first heat setting is subjected to a second soaping solution heated to 75-85℃ for a second soaping wash; the second soaping solution includes polyester-ammonia fastness enhancer, glacial acetic acid, and reducing cleaning agent; (vii) Second heat setting: The polyester fabric after the second soaping is heat set at a temperature of 120-130℃.

[0007] Furthermore, in step (ii), the memory fiber dyeing auxiliary is memory fiber dyeing auxiliary TF-259B, and the emulsifying refining agent is emulsifying refining agent TF-188A.

[0008] Furthermore, in step (iii), the leveling agent is leveling agent TF-212K, with a dosage of 0.6-0.8 g / L; the stabilizer is stabilizer EL-SF, with a dosage of 2-3 g / L.

[0009] Furthermore, in step (4), the amount of sodium hydroxide in the first soap washing solution is 0.8-1 g / L, and the amount of sodium hydrosulfite is 1.6-1.8 g / L.

[0010] Furthermore, in step (vi), the second soap washing solution includes 0.8-1 g / L of DM-2525, a polyester-ammonia fastness enhancer, 0.8-1 g / L of glacial acetic acid solution, and 0.8-1 g / L of TF-110B, a reducing cleaning agent.

[0011] The beneficial effects of this invention are as follows: The dyeing method for improving the color fastness of medium-dark polyester fabric involved in this invention, by selecting reasonable dye types and ratios, can stably control the color changes in subsequent soaping. Before dyeing, the use of memory fiber dyeing auxiliaries and emulsifiers in the same bath increases the permeability of the fabric surface during sizing. This effectively increases the dye uptake rate during the dyeing process, improves dye penetration, and reduces ring dyeing. Through a second soaping process, combined with the influence of heat and wind, dye molecules on the fiber surface and outer layer slowly migrate to the fiber surface, where they are removed and reduced to colorless substances during the second soaping process. Through two different temperature setting processes, the high-temperature setting fully releases the floating dye on the fiber surface and eliminates the internal stress of the fabric generated during the dyeing process, eliminating wrinkles and making the fabric surface smoother. The second setting at a lower temperature appropriately releases the internal stress of the fabric generated by the humid and hot environment during soaping, ultimately obtaining a medium-dark fabric with high color fastness and meeting the quality standards for product style and fabric surface. Detailed Implementation

[0012] The present invention will be further described below with reference to specific embodiments.

[0013] Example 1 The present invention relates to a dyeing method for improving the color fastness of medium-dark polyester fabrics, comprising the following steps: (I) Dye Selection: SFN-type high wash fastness dyes are selected, wherein Disperse Red SFN accounts for less than 15% of the total dye weight, Disperse Yellow SFN accounts for 25%-35% of the total dye weight, and the remainder is Disperse Blue SFN. In this embodiment, the amount of Disperse Red SFN is 12%, the amount of Disperse Yellow SFN is 30%, and the remainder is Disperse Blue SFN.

[0014] Regarding dye selection, due to the unique relationship between the color and molecular weight of disperse dyes, red dyes are generally affected by functional groups, resulting in a significant light-colored effect. The dye absorbs color and shifts towards lower wavelengths, thus appearing red. Consequently, they generally have smaller molecular weights, are not heat-resistant to sublimation, and easily migrate to the fiber surface during hot air drying, leading to poor color fastness after drying. In color selection, it is necessary to consider color depth, using blue dyes as the primary color depth agent, yellow dyes as secondary agents, and red dyes only for adjusting color. The red dye strength needs to be kept at a low level. By screening existing dye types, small-scale sampling and soaping were conducted with the same dye dot count and strength, and color fastness tests were performed on the samples. Dyes with smaller dye dot counts and higher strength were selected, resulting in better or adjustable color fastness during conventional wet treatment, thus achieving an initial improvement in color fastness during dyeing and finishing.

[0015] (II) Pre-dyeing treatment: The polyester fabric is immersed in the pre-dyeing treatment solution and heated to 115-120℃ for 25-35 minutes. The pre-dyeing treatment solution contains 1-1.5 g / L of memory fiber dyeing auxiliary agent and 0.5-1 g / L of emulsifying refining agent. Specifically, in this embodiment, the fabric is heated to 115℃ for 35 minutes, the amount of memory fiber dyeing auxiliary agent is 1.2 g / L, and the amount of emulsifying refining agent is 0.8 g / L. The polyester fabric selected in this embodiment is 210T polyester taffeta.

[0016] Furthermore, the memory fiber dyeing auxiliary is memory fiber dyeing auxiliary TF-259B, and the emulsifying refining agent is emulsifying refining agent TF-188A.

[0017] (III) Dyeing: The pre-treated polyester fabric is placed in the dye bath at 45-50℃, and the temperature is raised to 125-130℃ and held for 35-45 minutes. The dye bath includes a predetermined amount of SFN type high wash fastness dye, leveling agent, and stabilizer, and the pH value of the dye bath is controlled at 4.0-4.5. In this embodiment, the polyester fabric is placed in the dye bath at 45℃, the temperature of the dye bath is raised to 125℃ at a rate of 1℃ / min, held for 45 minutes, and the pH value of the dye bath is adjusted to 4.0.

[0018] Furthermore, the leveling agent is leveling agent TF-212K, with a dosage of 0.6-0.8 g / L; the stabilizer is stabilizer EL-SF, with a dosage of 2-3 g / L. Specifically, in this embodiment, the dosage of leveling agent TF-212K is 0.6 g / L, and the dosage of stabilizer EL-SF is 3 g / L. Before dyeing, the fabric is treated by scouring to maintain good fiber surface permeability. In addition to the conventional addition of refining agents and a small amount of memory fiber dyeing auxiliaries, the temperature is raised to above 115℃. The crystalline regions of the polyester fibers open, and more gaps appear in the crystalline regions. With the help of the refining agents, the memory fiber dyeing auxiliaries are fixed inside the fibers. Finally, the temperature is lowered to below the glass transition temperature, and the auxiliaries are fixed inside the fibers. The use of auxiliaries to improve the permeability of fiber components before dyeing enhances the dyeing performance of the fabric (i.e., the ability of dye to diffuse into the fiber). During the subsequent dyeing process, the amorphous regions of polyester reopen. With high fiber surface permeability, the dyeing process can effectively avoid fiber ring dyeing. In the dye bath, under the combined action of dye concentration difference and thermal motion, most dyes can migrate into the fiber, thus improving penetration dyeing.

[0019] During the comparison of dyeing samples before and after treatment, it was found that the fabric treated with memory fiber dyeing auxiliaries was basically dyed at 125℃ under the same color formula, while the untreated sample reached the dyeing endpoint after being kept at 130℃ for about 10 minutes. Moreover, it required to be kept at 130℃ for at least 60 minutes to achieve the dyeing effect, which effectively reduced the dyeing time, improved penetration, and reduced ring dyeing.

[0020] (iv) First soaping: The dyed polyester fabric is washed at 75℃ using a first soaping solution; the first soaping solution includes sodium hydroxide and sodium hydrosulfite. Further, the amount of sodium hydroxide in the first soaping solution is 0.8-1 g / L, and the amount of sodium hydrosulfite is 1.6-1.8 g / L. Specifically, in this embodiment, the amount of sodium hydroxide is 0.8 g / L, and the amount of sodium hydrosulfite is 1.6 g / L.

[0021] (v) First heat setting: The polyester fabric after the first soaping is subjected to the first heat setting at a temperature of 175-185℃. In this embodiment, the first heat setting is carried out at a temperature of 180℃.

[0022] (vi) Second soaping: The polyester fabric that has undergone the first heat setting is subjected to a second soaping wash at 75-85℃. The second soaping wash includes a polyester-spandex fastness enhancer, glacial acetic acid, and a reducing cleaning agent. Further, the second soaping wash includes 0.8-1 g / L of the polyester-spandex fastness enhancer DM-2525, 0.8-1 g / L of glacial acetic acid, and 0.8-1 g / L of the reducing cleaning agent TF-110B. Specifically, in this embodiment, the amount of polyester-spandex fastness enhancer DM-2525 is 0.8 g / L, the amount of glacial acetic acid is 0.8 g / L, and the amount of reducing cleaning agent TF-110B is 0.8 g / L.

[0023] (vii) Second heat setting: The polyester fabric after the second soaping is subjected to a second heat setting at a temperature of 120-130℃. In this embodiment, the second heat setting is carried out at a temperature of 130℃, and the speed is 40 km / h.

[0024] The production process employs a combination of soaping and heat setting. First, after fabric dyeing, it is washed, followed by a reduction cleaning process. After washing, it is dehydrated, opened, and heat-set at a high temperature. This serves two purposes: firstly, to eliminate the stress between fibers caused by prolonged humid and hot conditions and external forces during dyeing, laying the initial foundation for the finished product's style and quality; secondly, to heat the polyester to above its glass transition temperature. At this temperature, the molecular chain structure is relatively relaxed, and since disperse dyes are mostly small molecules, they are prone to sublimation and thermal migration. Dyes on the outer layer of the fiber can migrate to the fiber surface under the combined action of wind and heat. After the setting process, the polyester recools and undergoes secondary crystallization, fixing the outer dye to the outside of the fiber. Then, a reduction cleaning and color-fixing process is used, operating below the glass transition temperature of the polyester fiber, to destroy the color development system of the remaining dye on the fiber surface, transforming it into colorless substances and maximizing the removal of surface dye.

[0025] Finished product setting, also known as the second heat setting, can be done at a lower temperature. After the high-temperature heat setting process during the soaping stage, most of the inter-fiber stress is basically eliminated. Since the subsequent soaping temperature is lower and the time is shorter, the fabric will not generate significant internal stress due to the effects of moisture and heat and water flow. After reaching the glass transition temperature of polyester, heat setting can generally achieve good finished product quality.

[0026] The fabric prepared in this embodiment was tested for color fastness to perspiration, rubbing, water, and soap washing. The results are as follows: Example 2 The present invention relates to a dyeing method for improving the color fastness of medium-dark polyester fabrics, comprising the following steps: (I) Dye Selection: SFN-type high wash fastness dyes are selected, wherein Disperse Red SFN accounts for less than 15% of the total dye weight, Disperse Yellow SFN accounts for 25%-35% of the total dye weight, and the remainder is Disperse Blue SFN. In this embodiment, the amount of Disperse Red SFN is 8%, the amount of Disperse Yellow SFN is 25%, and the remainder is Disperse Blue SFN.

[0027] (II) Pre-dyeing treatment: The polyester fabric is immersed in the pre-dyeing treatment solution and heated to 115-120℃ for 25-35 minutes. The pre-dyeing treatment solution contains 1-1.5 g / L of memory fiber dyeing auxiliary agent and 0.5-1 g / L of emulsifying refining agent. Specifically, in this embodiment, the fabric is heated to 120℃ for 25 minutes, the amount of memory fiber dyeing auxiliary agent is 1.5 g / L, and the amount of emulsifying refining agent is 1 g / L. The polyester fabric selected in this embodiment is 240T polyester spring spun yarn.

[0028] (III) Dyeing: The pre-treated polyester fabric is placed in the dye bath at 45-50℃, and the temperature is raised to 125-130℃ and held for 35-45 minutes. The dye bath includes a predetermined amount of SFN type high wash fastness dye, leveling agent, and stabilizer, and the pH value of the dye bath is controlled at 4.0-4.5. In this embodiment, the polyester fabric is placed in the dye bath at 50℃, the temperature of the dye bath is raised to 130℃ at a rate of 1℃ / min, held for 35 minutes, and the pH value of the dye bath is adjusted to 4.5.

[0029] Furthermore, the leveling agent is leveling agent TF-212K, with a dosage of 0.6-0.8 g / L; the stabilizer is stabilizer EL-SF, with a dosage of 2-3 g / L. Specifically, in this embodiment, the dosage of leveling agent TF-212K is 0.8 g / L, and the dosage of stabilizer EL-SF is 2 g / L.

[0030] (iv) First soaping: The dyed polyester fabric is washed at 80℃ using a first soaping solution; the first soaping solution includes sodium hydroxide and sodium hydrosulfite. Further, the amount of sodium hydroxide in the first soaping solution is 0.8-1 g / L, and the amount of sodium hydrosulfite is 1.6-1.8 g / L. Specifically, in this embodiment, the amount of sodium hydroxide is 0.8 g / L, and the amount of sodium hydrosulfite is 1.6 g / L.

[0031] (v) First heat setting: The polyester fabric after the first soaping is subjected to the first heat setting at a temperature of 175-185℃. In this embodiment, the first heat setting is carried out at a temperature of 185℃.

[0032] (vi) Second soaping: The polyester fabric that has undergone the first heat setting is subjected to a second soaping wash at 75-85°C. The second soaping wash includes a polyester-spandex fastness enhancer, glacial acetic acid, and a reducing cleaning agent. Further, the second soaping wash includes 0.8-1 g / L of the polyester-spandex fastness enhancer DM-2525, 0.8-1 g / L of glacial acetic acid, and 0.8-1 g / L of the reducing cleaning agent TF-110B. Specifically, in this embodiment, the amount of polyester-spandex fastness enhancer DM-2525 is 1 g / L, the amount of glacial acetic acid is 1 g / L, and the amount of reducing cleaning agent TF-110B is 1 g / L.

[0033] (vii) Second heat setting: The polyester fabric after the second soaping is subjected to a second heat setting at a temperature of 120-130℃. In this embodiment, the second heat setting is carried out at a temperature of 125℃, and the speed is 35 km / h.

[0034] The fabric prepared in this embodiment was tested for color fastness to perspiration, rubbing, water, and soap washing. The results are as follows: The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A dyeing method for improving the color fastness of medium-dark polyester fabrics, characterized in that, Includes the following steps: (I) Selection of dyes: Select SFN type high wash fastness dyes, wherein Disperse Red SFN accounts for less than 15% of the total dye weight, Disperse Yellow SFN accounts for 25%-35% of the total dye weight, and the remainder is Disperse Blue SFN; (II) Pre-dyeing treatment: The polyester fabric is placed in the pre-dyeing treatment solution and heated to 115-120℃ for 25-35 minutes; the pre-dyeing treatment solution contains 1-1.5 g / L of memory fiber dyeing auxiliary agent and 0.5-1 g / L of emulsifying refining agent. (III) Dyeing: The pre-treated polyester fabric is placed in the dye bath at 45-50℃, and the temperature is raised to 125-130℃ and kept at that temperature for 35-45 minutes. The dye bath contains SFN type high wash fastness dye, leveling agent and stabilizer in a set amount, and the pH value of the dye bath is controlled to be 4.0-4.

5. (iv) First soaping: The dyed polyester fabric is washed with the first soaping solution at 75-85℃; the first soaping solution includes sodium hydroxide and sodium hydrosulfite. (v) First heat setting: The polyester fabric after the first soaping is heat set at a temperature of 175-185℃. (vi) Second soaping: The polyester fabric that has undergone the first heat setting is subjected to a second soaping solution heated to 75-85℃ for a second soaping wash; the second soaping solution includes polyester-ammonia fastness enhancer, glacial acetic acid, and reducing cleaning agent; (vii) Second heat setting: The polyester fabric after the second soaping is heat set at a temperature of 120-130℃.

2. The dyeing method for improving the color fastness of medium-dark polyester fabric according to claim 1, characterized in that, In step (ii), the memory fiber dyeing auxiliary is memory fiber dyeing auxiliary TF-259B, and the emulsifying refining agent is emulsifying refining agent TF-188A.

3. The dyeing method for improving the color fastness of medium-dark polyester fabric according to claim 1, characterized in that, In step (iii), the leveling agent is leveling agent TF-212K, and the dosage is 0.6-0.8 g / L; the stabilizer is stabilizer EL-SF, and the dosage is 2-3 g / L.

4. The dyeing method for improving the color fastness of medium-dark polyester fabric according to claim 1, characterized in that, In step (4), the amount of sodium hydroxide in the first soap washing solution is 0.8-1 g / L, and the amount of sodium hydrosulfite is 1.6-1.8 g / L.

5. The dyeing method for improving the color fastness of medium-dark polyester fabric according to claim 1, characterized in that, In step (six), the second soaping solution includes 0.8-1 g / L of DM-2525, a polyester-ammonia fastness enhancer, 0.8-1 g / L of glacial acetic acid, and 0.8-1 g / L of TF-110B, a reducing cleaning agent.

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