Normal-temperature normal-pressure dyeable polyester fiber and chinlon composite yarn one-bath dyeing method

Abstract

According to the normal-temperature and normal-pressure dyeable polyester fiber and chinlon composite yarn one-bath-process dyeing method, normal-temperature and normal-pressure dyeable polyester fibers are adopted to replace conventional polyester, synchronous one-bath-process dyeing of polyester and chinlon composite yarn under the normal-pressure condition is achieved, and the technical problem caused by the difference of the dyeing characteristics of two kinds of fibers in a traditional technology is solved. A traditional multi-step two-bath method is integrated into one step, so that the technological process is shortened by more than 50%, and the production efficiency is greatly improved. High-temperature and high-pressure equipment is not needed, and the replacement frequency of the dye liquor is reduced, so that the steam energy consumption is reduced by about 40%, the water consumption and the wastewater discharge amount are reduced by about 35%, and the green manufacturing requirement is met. The mild dyeing conditions of the process effectively protect the mechanical properties of the polyamide fibers, so that the strength retention rate of the polyamide fibers is increased by 15% or above, and excellent leveling property and color fastness are ensured. The operability and reproducibility of the process are also enhanced by the single-bath process, and a reliable guarantee is provided for large-scale stable production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular materials, in particular, a one-bath dyeing process method of normal temperature and pressure dyeable polyester fiber and nylon composite yarn. BACKGROUND

[0002] As two synthetic fibers, polyester and nylon are widely made into composite yarns through blending and interweaving due to their complementary properties, and are widely used in high-end sportswear, outdoor equipment and fashion clothing to meet the market demand for comprehensive performance of fabrics.

[0003] However, in the dyeing and finishing process, the different molecular structures and dyeing properties of polyester and nylon pose a core technical challenge. Conventional polyester fiber has a compact structure and a high glass transition temperature, and must rely on high temperature and high pressure conditions and disperse dyes to achieve effective dyeing. As a polyamide fiber, the molecular chain of nylon is prone to hydrolysis under the same high temperature and high pressure and acidic environment, which significantly reduces the fiber strength, elasticity and wear resistance, and seriously affects the quality of the finished product.

[0004] To address the above-mentioned contradictions, the existing technology mainly adopts a "two-bath process", that is, the polyester component is dyed in a high temperature and high pressure environment, and after draining, a new dyeing solution is used to dye the nylon component under normal pressure. This process not only has a complicated process and a long time-consuming, but also has many defects such as high energy and water consumption, high wastewater discharge, poor color synchronization, color difference, use of toxic carriers to assist dyeing, environmental and hand feeling problems, and the like. Therefore, the industry urgently needs to develop a new dyeing method for polyester-nylon composite yarn that can balance high efficiency, energy saving, environmental protection and high quality. SUMMARY

[0005] In view of the above problems, a one-bath dyeing method for normal temperature and pressure dyeable polyester fiber and nylon composite yarn is provided to overcome the above problems or at least partially solve the above problems, which specifically includes the following steps: After the normal temperature and pressure dyeable polyester fiber and nylon composite yarn is loaded into the dyeing vat, soft water is injected and a refining agent is added to prepare a pretreatment solution. After circulating at 50-60°C for 15-20 minutes, the liquid in the dyeing vat is drained to obtain the pretreated composite yarn, and the dyeing vat and the pretreated composite yarn are cleaned. Soft water is re-injected into the dyeing vat, a dye bath with a pH value of 5.0-6.0 is configured, and composite auxiliaries, low-temperature disperse dyes and weak acid dyes are sequentially added to the dyeing vat. The pretreated composite yarn is put into the dyeing vat at 40°C, and the reaction system is uniformly heated to 98-100°C at a rate of 1.0-1.5°C / min, and then dyed at 98-100°C for 30-40 min. After dyeing, the reaction system is cooled to 60-70℃ at a rate of 1.5-2.0℃ / min, the dye liquor in the dyeing vat is discharged, the dyed composite yarn is subjected to one-bath reduction cleaning, and then is subjected to hot water washing and cold water washing in sequence until the washing liquor is neutral, and the dyed composite yarn is dehydrated and dried.

[0006] Optionally, the normal temperature and pressure dyeable polyester fiber is obtained by introducing flexible chain segments or bulky side groups into polyester macromolecular chains, wherein the glass transition temperature of the normal temperature and pressure dyeable polyester fiber is 60-75℃.

[0007] Optionally, the composite yarn is a composite yarn composed of the normal temperature and pressure dyeable polyester fiber and the conventional polyamide fiber by blending, interweaving or covering.

[0008] Optionally, the amount of the refining agent is 1.0-2.0 g / L of the pretreatment liquor.

[0009] Optionally, the pH value of the dye bath is maintained by an acetic acid-sodium acetate buffer system.

[0010] Optionally, the composite auxiliary agent is a complex of an anionic surfactant and a nonionic surfactant, and the amount is 1.5-3.0 g / L of the dye liquor.

[0011] Optionally, the amount of the low-temperature type disperse dye is 0.5%-6% based on the mass of the normal temperature and pressure dyeable polyester fiber component.

[0012] Optionally, the amount of the weak acid dye is 0.3%-2% based on the mass of the conventional polyamide fiber component.

[0013] Optionally, the one-bath reduction cleaning includes: cleaning at 50-60℃ for 15-20 min by using a reduction cleaning agent containing a special chelating agent or a mixed solution prepared by stirring 1-2 g / L of sodium hydroxide, 1-2 g / L of sodium dithionite and soft water; wherein the special chelating agent is composed of natural soap kernel refining extract, alkaline blending agent, oxidizing agent, alkyl polyglycoside hydrolysate and high molecular polymer.

[0014] Optionally, the bath ratio of the dye bath is 1:15.

[0015] The present application realizes the simultaneous one-bath dyeing of polyester-polyamide composite yarn under normal pressure by using normal-temperature and normal-pressure dyeable polyester fiber to replace conventional polyester, and solves the technical problems caused by the difference in dyeing characteristics of the two fibers in traditional process. The traditional multi-step two-bath process is integrated into one step, which shortens the process by more than 50%, and greatly improves the production efficiency. In terms of energy saving and environmental protection, since high-temperature and high-pressure equipment is not needed and the number of dye liquid changes is reduced, steam energy consumption is reduced by about 40%, water consumption and wastewater discharge are reduced by about 35%, which meets the requirements of green manufacturing. The mild dyeing conditions effectively protect the mechanical properties of polyamide fiber, and the strength retention rate is increased by more than 15%, which ensures excellent level dyeing and color fastness. The single-bath process also enhances the operability and reproducibility of the process, providing a reliable guarantee for large-scale stable production. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the description of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0017] Figure 1 It is a normal-temperature and normal-pressure dyeable polyester fiber and polyamide composite yarn one-bath dyeing method flow chart provided by the embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the following will further describe the present application in detail with reference to the drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0019] REFERENCE Figure 1 The embodiment of the present application provides a normal-temperature and normal-pressure dyeable polyester fiber and polyamide composite yarn one-bath dyeing method, which can specifically include the following steps: S1, after the normal-temperature and normal-pressure dyeable polyester fiber and polyamide composite yarn are loaded into the dyeing vat, soft water is injected and refining agent is added to prepare a pretreatment liquid, after circulating at 50-60℃ for 15-20min, the liquid in the dyeing vat is discharged, and the pretreated composite yarn is obtained, and the dyeing vat and the pretreated composite yarn are cleaned; wherein the amount of refining agent can be 1.0-2.0g / L of pretreatment liquid.

[0020] In the embodiment of the present application, the normal temperature and pressure dyeable polyester fiber is polyester fiber obtained by introducing flexible chain segments or bulky side groups into polyester macromolecular chains, wherein the glass transition temperature of the normal temperature and pressure dyeable polyester fiber is 60-75℃.

[0021] In actual operation, the third monomer, such as sodium 5-sulfoisophthalate (SIPE) or other monomers containing sulfonic acid groups or other flexible structures, can be introduced accurately in the traditional polyester polymerization process, so as to embed flexible chain segments or graft bulky side groups in the originally rigid molecular backbone.

[0022] It can be understood that the introduction of flexible chain segments effectively weakens the interaction between polyester macromolecular chains and increases the movement ability of chain segments; secondly, the existence of bulky side groups produces a steric hindrance effect similar to "molecular level spacer", which hinders the close packing of macromolecular chains. The synergistic effect of the two effects significantly increases the proportion of the amorphous region of the fiber and makes the internal structure more loose. The most direct and quantifiable performance is that the glass transition temperature (Tg) is reduced to the range of 60-75℃.

[0023] The reduction of the glass transition temperature is the core mechanism for realizing the normal pressure dyeing of the fiber. Under the traditional 100℃ boiling dyeing conditions, the conventional polyester has a Tg higher than this temperature, and the molecular chain segments are still in a frozen state, so it is difficult for dye molecules to diffuse into the interior of the fiber. The Tg of the normal temperature and pressure dyeable polyester fiber (ECDP) of the present application is reduced to 60-75℃, at which temperature the molecular chain segments of the amorphous region begin to move violently and the free volume increases, opening sufficient diffusion channels for dispersed dye molecules, so that the dye can be smoothly and quickly dyed and fixed in the interior of the fiber, realizing the dyeing depth and color fastness comparable to conventional polyester under mild conditions without high temperature and high pressure.

[0024] In the embodiment of the present application, the composite yarn is a composite yarn composed of the normal temperature and pressure dyeable polyester fiber and the conventional polyamide fiber by blending, interweaving or covering.

[0025] Specifically, blended composite yarns are made by uniformly mixing ECDP fibers and nylon fibers in a predetermined ratio as short fibers through traditional spinning processes such as drawing, roving, and spinning. This structure ensures that the two fibers are randomly distributed in both the cross-section and longitudinal direction of the yarn, guaranteeing the uniformity of the yarn color and the blending effect after dyeing. Interwoven composite yarns, on the other hand, are made by interweaving ECDP filaments or yarns with nylon filaments or yarns in a warp-weft interlacing manner during the weaving process. This structure utilizes the different properties of the two fibers to give the fabric specific properties and appearance, and through the process of this invention, simultaneous dyeing can be achieved to obtain unique two-tone or iridescent effects. Covered composite yarns typically use one fiber (such as nylon or ECDP multifilament) as the core yarn, and another fiber (such as ECDP or nylon filament / short fiber yarn) is wrapped around, wound, or wrapped around its outer layer. For example, using high-strength nylon multifilament as the core and ECDP short fiber yarn as the outer layer can obtain both the core strength provided by nylon and the surface characteristics of ECDP fibers that are easy to dye. This structure allows the yarn to exhibit an appearance color primarily determined by the outer fibers after dyeing, while the properties of the inner core yarn are fully preserved. Those skilled in the art can freely choose the configuration of the composite yarn according to actual needs.

[0026] Regarding step S1, in practical applications, the room-temperature and room-pressure dyeable polyester fiber and nylon composite yarn can be first loaded into the dyeing vat. Subsequently, an appropriate amount of soft water is added to the vat, along with a refining agent at a concentration of 1.0-2.0 g / L of pretreatment solution.

[0027] After preparing the pretreatment solution, circulate it at 50℃-60℃ for 15-20 minutes. It is understood that too low a temperature will reduce the emulsification, saponification, and dispersion efficiency of the refining agent, resulting in incomplete oil removal; while too high a temperature can improve cleaning efficiency, it will increase energy consumption and pose a potential risk of damage to the heat-sensitive nylon component. At this optimized temperature, the refining agent can effectively break down the oil film and emulsify and disperse it in the water without damaging any component fiber.

[0028] After treatment, the yarn must be thoroughly washed, typically 2-3 times, to ensure complete removal of all dirt and chemical auxiliaries detached from the fibers. Any residue can hinder subsequent dyeing, causing stains or affecting color. The resulting pretreated composite yarn is clean, hydrophilic, and has a near-neutral pH, creating conditions for uniform dye adsorption and diffusion in the subsequent dye bath.

[0029] S2. Refill the dye bath with soft water to prepare a dye bath with a pH of 5.0-6.0. Add the composite auxiliary agent, low-temperature disperse dye, and weakly acidic dye sequentially to the dye bath. The pH of the dye bath can be maintained using an acetate-sodium acetate buffer system. The composite auxiliary agent is a complex of anionic and nonionic surfactants, used at a rate of 1.5–3.0 g / L of dye liquor. The amount of low-temperature disperse dye is 0.5%-6% of the mass of the room-temperature, room-pressure dyeable polyester fiber component. The amount of weakly acidic dye is 0.3%-2% of the mass of the conventional nylon fiber component.

[0030] In a preferred embodiment of the present invention, the bath ratio can be 1:15.

[0031] In practical applications, after completing pretreatment and draining the washing solution, soft water with the specified liquor ratio can be refilled into the dye bath to begin preparing the core dye bath. An acetate-sodium acetate buffer system is used to precisely adjust and stabilize the initial pH of the dye bath within the range of 5.0-6.0. This weakly acidic environment not only provides the optimal pH conditions for the adsorption and fixation of weakly acidic dyes on nylon fibers, but also effectively ensures the dispersion stability of low-temperature disperse dyes during subsequent temperature-increasing dyeing processes, preventing dye aggregation or charring in the dye bath.

[0032] When preparing the dye solution, the first step is to add a composite auxiliary agent at a dosage of 1.5–3.0 g / L of dye liquor. This auxiliary agent is a scientifically formulated blend of anionic and nonionic surfactants. Adding it at this stage allows it to be fully and evenly dispersed in the dye liquor, pre-occupying the dyeing sites on the fiber surface, effectively slowing down the dyeing process, and establishing a stable dispersion system for the dyes added subsequently.

[0033] Subsequently, the low-temperature disperse dye is slowly added. It is understandable that if a pH-sensitive weakly acidic dye is added first, the subsequently added disperse dye may interact with the already dissolved acidic dye due to its inherent hydrophobicity and suboptimal dispersion, leading to color spots or dye aggregates. Therefore, prioritizing the addition of the disperse dye, ensuring its full encapsulation and dispersion within the well-established dispersion environment of the composite auxiliaries, is a crucial step in guaranteeing dyeing uniformity.

[0034] Finally, after the disperse dye has been completely added and circulated evenly, the weakly acidic dye is added. At this point, a dye bath configuration is complete, comprising a stable pH environment, a uniformly dispersed dye system, and a highly efficient auxiliary agent system.

[0035] S3. Put the pretreated composite yarn into the dyeing vat at 40℃, circulate for 10min-15min, and uniformly heat the reaction system to 98℃-100℃ at a rate of 1.0℃-1.5℃ / min. Then keep it at 98℃-100℃ for 30min-40min for dyeing.

[0036] In practical applications, the pretreated composite yarn can be placed into a dye bath with a prepared dye solution, and the initial temperature should be controlled at 40℃. At this temperature, the dye solution should be circulated for 10 to 15 minutes. This allows the yarn to be fully wetted and evenly expanded in the dye bath, ensuring that the low-temperature disperse dye and the weakly acidic dye achieve initial and uniform adsorption in the dye bath and on the fiber surface. This guarantees smooth dyeing in the subsequent heating stage and effectively prevents color unevenness caused by uneven initial adsorption.

[0037] Subsequently, the temperature control program was activated, and the dye bath system was uniformly heated to 98℃-100℃ at a controlled rate of 1.0℃ / min to 1.5℃ / min. This uniform heating rate ensures a stable diffusion rate of dye molecules from the dye bath into the fiber. For ECDP fibers, as the temperature gradually approaches and exceeds their glass transition temperature, the mobility of molecular chain segments increases, and the amorphous regions gradually open, creating conditions for the continuous diffusion of disperse dyes into the fiber interior. For nylon fibers, a gradual heating also facilitates the orderly and uniform binding of weakly acidic dye molecules with the amide groups and terminal amino groups on the nylon macromolecular chains. If the temperature rises too quickly, it can easily lead to a large amount of dye being instantly adsorbed and accumulated on the fiber surface, resulting in uneven diffusion inwards and producing irreparable color spots or ring dyeing.

[0038] Once the temperature reaches the set 98℃-100℃, the dyeing process is maintained at this boiling point for 30 to 40 minutes. This holding stage is crucial for the dye to fully diffuse and penetrate into the fiber, ultimately achieving fixation. Under the combined effect of heat and continuous dye liquor circulation, the low-temperature disperse dye molecules adsorbed on the ECDP fiber surface gain sufficient kinetic energy to completely break through the fiber barrier and enter and fix within the amorphous region of the fiber. Simultaneously, the ionic and hydrogen bonds between the weakly acidic dye and the nylon fiber are fully established and strengthened at this optimal temperature, thus achieving synchronous and deep fixation of the two dyes on their respective fiber components. Sufficient holding time ensures sufficient dye migration, further improving dyeing uniformity, hiding power, and final colorfastness. The entire dyeing process is completed under normal pressure, completely avoiding the risk of damage to the nylon caused by high temperature and high pressure conditions.

[0039] S4. After dyeing, the reaction system is cooled to 60℃-70℃ at a rate of 1.5℃-2.0℃ / min, and the dye solution in the dyeing vat is drained. The dyed composite yarn is then subjected to a one-bath reduction cleaning, followed by hot water washing and cold water washing in sequence until the washing solution is neutral. The dyed composite yarn is then dehydrated and loosely dried.

[0040] In an embodiment of the present invention, the one-bath reduction cleaning includes: cleaning for 15-20 minutes at 50°C-60°C using a reduction cleaning agent containing a special chelating agent, or a mixed solution consisting of 1-2 g / L sodium hydroxide, 1-2 g / L sodium hydrosulfite, and soft water; wherein the special chelating agent is composed of a refined extract of natural soapberry, an alkaline modifier, an oxidizing agent, alkyl polysaccharide hydrolysate, and a high molecular polymer.

[0041] During operation, the dyeing system can be slowly cooled to 60℃-70℃ at a precise rate of 1.5℃-2.0℃ / minute. This avoids uneven fiber shrinkage or redistribution of dye on the surface caused by sudden temperature changes, effectively preventing dyeing creases or uneven coloring. Once the temperature stabilizes within the set range, the system automatically discharges the dye liquor.

[0042] This is followed by a one-bath reduction cleaning process. This step is carried out within a temperature range of 50℃-60℃ and can be performed using two equivalent methods: one is to use a specially formulated reduction cleaning agent containing a special chelating agent; the other is to use a mixed solution prepared by stirring 1-2 g / L of sodium hydroxide, 1-2 g / L of sodium hydrosulfite, and soft water. The cleaning time is controlled at 15-20 minutes.

[0043] It is understandable that sodium hydrosulfite (preferably sodium dithionite), as a strong reducing agent, can reduce and decompose the chromophores such as azo groups in the unfixed disperse dye molecules on the fiber surface, causing them to lose their color. Simultaneously, sodium hydroxide in an alkaline environment not only provides the necessary reaction conditions but also saponifies and removes some of the dye. Furthermore, a special chelating agent effectively complexes metal ions and dye decomposition products in the water, preventing them from redepositing on the fiber surface. This synergistic effect ensures the complete removal of floating dye, guaranteeing colorfastness.

[0044] After the initial cleaning, the yarn enters a tiered washing process. First, it is thoroughly washed with hot water at 50℃-60℃, utilizing heat to promote water molecule diffusion and effectively remove residual chemical auxiliaries and dye decomposition products. Then, it is switched to room temperature cold water washing, where continuous water exchange thoroughly removes residual substances from the fiber's interior and surface until the pH of the discharged water is neutral. This gradual washing process ensures both cleaning efficiency and water conservation. Finally, the treated composite yarn is centrifuged and then dried using a loose drying process. This drying method ensures the yarn shrinks freely without tension, resulting in a fluffy and soft hand feel while preserving the dyeing results.

[0045] This invention, by replacing conventional polyester with room-temperature and room-pressure dyeable polyester fiber, achieves simultaneous one-bath dyeing of polyester-nylon composite yarn under normal pressure, solving the technical difficulties caused by the differences in dyeing characteristics between the two fibers in traditional processes. It integrates the traditional multi-step, two-bath process into a single step, shortening the process flow by more than 50% and significantly improving production efficiency. It also demonstrates outstanding energy-saving and environmental protection capabilities. Because it eliminates the need for high-temperature and high-pressure equipment and reduces the number of dye liquor changes, steam energy consumption is reduced by approximately 40%, and water consumption and wastewater discharge are reduced by approximately 35%, meeting green manufacturing requirements. The gentle dyeing conditions effectively protect the mechanical properties of nylon fibers, increasing their strength retention rate by more than 15%, ensuring excellent level dyeing and color fastness. The single-bath process also enhances the operability and reproducibility of the process, providing a reliable guarantee for large-scale stable production.

[0046] The above is the overall concept of the present invention. For ease of understanding, the present invention also provides the following embodiments.

[0047] 1. Dyeing materials and equipment Dyeing material: 60 / 40 ECDP fiber / nylon 6 blended yarn. Among them, the ECDP fiber is modified by copolymerization to introduce flexible segments, and its glass transition temperature (Tg) is about 65℃, which allows it to be dyed with disperse dyes under normal pressure boiling dyeing conditions; the nylon 6 is a standard specification.

[0048] Main equipment: ambient temperature and pressure overflow dyeing machine, electronic balance, pH meter.

[0049] Staining bath ratio: 1:15.

[0050] 2. Bath dye formula Acetic acid-sodium acetate buffer system: It precisely stabilizes the pH value of the dye bath at 5.5. Firstly, it is the optimal pH range for weakly acidic dyes to achieve the best dyeing rate and color fastness on nylon 6. Secondly, it can ensure the chemical stability of low-temperature disperse dyes in the dye bath and prevent their hydrolysis or aggregation.

[0051] Composite auxiliaries (2.0 g / L dye liquor): This is an anionic / nonionic surfactant complex. As a dispersant, it can prevent hydrophobic disperse dyes from agglomerating; as a leveling agent, it can regulate the adsorption rate of the two dyes onto their respective fibers; it also helps maintain pH stability.

[0052] Dye Combinations: Low-temperature disperse yellow-brown S-2BL (1.2% owf) and low-temperature disperse red ruby ​​S-5BL (0.8% owf): The molecular structure and low directness of these two low-temperature disperse dyes allow them to effectively diffuse into the amorphous region of ECDP fibers and fix at temperatures below 100°C. Dosage is calculated based on the total weight of the composite yarn.

[0053] Weakly Acid Brown DR (1.5% owf): This dye has a high affinity for nylon 6 and can bind to nylon molecules via ionic bonds under the same weakly acidic conditions and temperature. Its dosage is calculated based on the mass of the nylon component in the composite yarn.

[0054] 3. Dyeing process flow The yarn is placed in a dyeing vat, and soft water and a refining agent at a concentration of 1.5 g / L of pretreatment solution are added. The vat is then treated at 55°C for 18 minutes to remove spinning oils and weaving contaminants, ensuring uniformity in subsequent dyeing. After treatment, the dyeing solution is drained, and the yarn is rinsed.

[0055] Pour the prescribed amount of soft water into the dyeing vat and start the circulation. Add the acetate-sodium acetate buffer solution, the compound auxiliaries, and the three accurately weighed dyes in sequence, and run for 10 minutes to ensure thorough mixing.

[0056] The pretreated yarn is immersed in a dye bath at 40°C and circulated for 10 minutes to fully wet the yarn and allow for initial dye adsorption. Subsequently, the temperature is uniformly increased to 99°C at a strictly controlled rate of 1.2°C / minute.

[0057] The dyeing process was carried out at 99℃ for 35 minutes. During this stage, the heat intensified the movement of molecular chain segments in the amorphous region of the ECDP fiber, opening up a sufficiently large free volume, allowing the low-temperature disperse dye to diffuse smoothly into the fiber interior and fix. At the same time, the weakly acidic dye also diffused fully into the nylon 6 fiber interior and formed a strong bond with the amide groups. The two dyes achieved simultaneous dyeing onto their respective target fibers in the same bath and at the same temperature profile.

[0058] After dyeing, the temperature is slowly lowered to 70°C at a rate of 1.5°C / minute, and then the main dye bath is drained. Slow cooling helps the dye molecules to be more firmly positioned inside the fiber, reducing surface floating dye.

[0059] Refill with water and treat with a reducing cleaning agent containing a special chelating agent at 55°C for 20 minutes. This step aims to thoroughly remove excess dye and residual auxiliaries adhering to the fiber surface and is essential for obtaining high color fastness (especially wet rubbing fastness).

[0060] Perform hot water washing (preferably 70℃) followed by running cold water washing until the washing solution is neutral. Finally, dehydrate the yarn and loosely dry it.

[0061] The yarn processed using this embodiment exhibits a uniform and full coffee color, free from color variations or uneven coloring. Tests show that the nylon component retains over 96% of its breaking strength, effectively avoiding damage caused by traditional high-temperature processes (which retain approximately 80% of their strength). The finished yarn achieves a wash fastness and rubbing fastness of 4-5 or higher, exceeding national standards. This fully demonstrates the superior effectiveness of this invention in protecting fiber properties and improving dyeing quality. Furthermore, compared to the traditional two-bath method, the total processing time is reduced from approximately 4 hours to less than 2 hours.

[0062] The above provides a detailed description of the one-bath dyeing method for room-temperature and room-pressure dyeable polyester fiber and nylon composite yarn. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A one-bath dyeing method for a common temperature and pressure dyeable polyester fiber and a polyamide fiber composite yarn, characterized in that, The process comprises the following steps: After the normal temperature and pressure dyeable polyester fiber and the polyamide composite yarn are put into the dyeing vat, soft water is injected and a refining agent is added to prepare a pretreatment liquid, after 15-20 minutes of circulation at 50-60℃, the liquid in the dyeing vat is discharged to obtain the pretreated composite yarn, and the dyeing vat and the pretreated composite yarn are cleaned; Soft water is injected into the dyeing vat again, a dye bath with a pH value of 5.0-6.0 is configured, and composite additives, low-temperature type disperse dyes and weak acid dyes are sequentially added into the dyeing vat; The pretreated composite yarn is put into the dyeing vat at 40℃, and the system is circulated for 10-15 minutes, and then the reaction system is uniformly heated to 98-100℃ at a rate of 1.0-1.5℃ / min, and then the dyeing is carried out at 98-100℃ for 30-40 minutes; After the dyeing is completed, the reaction system is cooled to 60-70℃ at a rate of 1.5-2.0℃ / min, and then the dyeing liquid in the dyeing vat is discharged, the dyed composite yarn is subjected to one-bath reduction cleaning, and then hot water washing and cold water washing are sequentially carried out until the washing liquid is neutral, the dyed composite yarn is dehydrated and loosely dried.

2. The method of claim 1, wherein, The normal temperature and pressure dyeable polyester fiber is obtained by introducing flexible chain segments or bulky side groups into polyester macromolecular chains, wherein the glass transition temperature of the normal temperature and pressure dyeable polyester fiber is 60-75℃.

3. The method of claim 2, wherein, The composite yarn is a composite yarn composed of normal temperature and pressure dyeable polyester fiber and conventional polyamide fiber by blending, interweaving or covering.

4. The method of claim 3, wherein, The amount of the refining agent is 1.0-2.0 g / L of the pretreatment liquid.

5. The method of claim 4, wherein, The pH value of the dye bath is maintained by an acetic acid-sodium acetate buffer system.

6. The method of claim 5, wherein, The composite additive is a complex of anionic surfactants and non-ionic surfactants, and the amount is 1.5-3.0 g / L of the dyeing liquid.

7. The method of claim 6, wherein, The amount of the low-temperature type disperse dye is 0.5%-6% based on the mass of the normal temperature and pressure dyeable polyester fiber component.

8. The method of claim 7, wherein, The amount of the weak acid dye is 0.3%-2% based on the mass of the conventional polyamide fiber component.

9. The method of claim 8, wherein, The one-bath reduction cleaning comprises: cleaning for 15-20 minutes at 50-60℃ using a reduction cleaning agent containing a special chelating agent, or a mixed solution prepared by stirring 1-2 g / L of sodium hydroxide, 1-2 g / L of sodium dithionite and soft water; wherein the special chelating agent is composed of natural soap kernel refining extract, alkaline blending agent, oxidizing agent, alkyl polyglycoside hydrolysate and high molecular polymer.

10. The method according to claim 1 or 9, characterized in that, The bath ratio of the dye bath is 1:

15. ​

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