A brocade fabric and a method for improving the storage color fastness of the brocade fabric

Abstract

This invention relates to the field of textile printing and dyeing technology, and particularly to a method for improving the storage color fastness of nylon-spandex fabrics. The improvement method includes the following steps: dyeing: dyeing the nylon-spandex fabric with acidic reactive dyes; post-treatment: sequentially including fixation treatment, washing treatment, and neutralization treatment; setting: padding the dyed nylon-spandex fabric with a cationic fixing agent with film-forming function, followed by high-temperature setting, so that the cationic film-forming fixing agent cross-links on the fiber surface to form a protective film. The beneficial effects of this invention are: this invention works synergistically from two different dimensions—chemical bonding and physical barrier—preventing dye molecules from desorbing from the fiber or migrating outward under high-temperature and high-humidity storage conditions, thereby significantly improving the storage color fastness of nylon-spandex fabrics and effectively solving the technical problem of color change and staining in dark-colored nylon-spandex fabrics during long-term storage.

Description

Technical Field

[0001] This invention relates to the field of textile printing and dyeing technology, and in particular to a nylon-spandex fabric and a method for improving the storage color fastness of nylon-spandex fabrics. Background Technology

[0002] Nylon-spandex blends (woven fabrics of nylon and spandex) are widely used in high-value-added apparel sectors such as sportswear, underwear, and swimwear due to their excellent elasticity and comfort. Dyeing nylon-spandex blends typically uses acid dyes because nylon molecules contain amino groups at their ends. Under acidic conditions, these amino groups protonate to form positively charged ammonium groups, which then bind to anions ionized from the acid dye through ionic bonds, supplemented by hydrogen bonds and van der Waals forces to complete the dyeing process. However, nylon has a low amino content, limiting the dyeing "sites." A large amount of dye remains on the fiber surface as floating dye after dyeing, failing to form strong chemical bonds. Furthermore, the dyeing rates of nylon and spandex differ significantly, easily leading to uneven dyeing and spandex staining problems.

[0003] During long-term storage, nylon-spandex fabrics exhibit poor color fastness to storage and water immersion due to insufficient binding force between dyes and fibers, and the tendency of dye molecules to hydrolyze and migrate under humid and hot conditions. This significantly impacts product quality and consumer experience. Unlike conventional wash fastness, storage fastness primarily examines the fabric's ability to resist hydrolysis, sublimation, and migration under humid and hot static conditions (typical test conditions specified in national standard GB / T 32008-2015: temperature 70℃±2, relative humidity 80%±5, time 3h). In high-temperature and high-humidity environments, unfixed dyes or dyes with weak binding forces can migrate from the fiber interior to the fiber surface, causing color changes and even staining adjacent light-colored fabrics.

[0004] Currently, conventional processes for improving the color fastness of nylon-spandex fabrics mainly focus on washability or perspiration resistance. For example, Chinese patent document CN202410553991.X discloses a dyeing and finishing method for improving the wet treatment color fastness of nylon-spandex elastic knitted fabrics. This method combines the dyeing and fixing processes by adding a color fastness enhancer to the dyeing working solution. However, this method mainly targets the color fastness of wet treatments such as washing, soaking, immersion, and perspiration. Its fixing mechanism relies on hydrogen bonds, van der Waals forces, and electrostatic interactions between the dye and fiber, and does not involve constructing a physical barrier layer on the fiber surface to resist dye thermal migration and hydrolysis during storage.

[0005] More importantly, the aforementioned conventional processes typically emphasize the hydrophilicity and wettability of fabrics. Therefore, in the finishing and setting stage, the conventional practice is to avoid using film-forming cationic fixing agents. This is because it is generally believed that cationic fixing agents will form a hydrophobic film on the fiber surface, leading to decreased water absorption, a rougher hand feel, and potentially affecting subsequent printing or sewing performance. Therefore, conventional processes often maintain basic fastness by increasing the amount of dye or simply washing away excess dye, neglecting the unique challenges posed by the static, humid, and hot environment of long-term storage.

[0006] Therefore, there is an urgent need for a systematic method to improve the storage color fastness of nylon-spandex fabrics, which can simultaneously improve both storage color fastness and water fastness, while minimizing staining of the spandex and providing high shape stability. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a nylon-spandex fabric and a method for improving the storage color fastness of nylon-spandex fabric, thereby solving the technical problem of color change of nylon-spandex fabric under high temperature and high humidity environment.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for improving the storage color fastness of nylon-spandex fabrics, comprising the following steps: (1) Dyeing: Acid reactive dyes are used to dye nylon-spandex fabrics; (2) Crosslinking and fixing treatment: The dyed nylon and urethane fabric is treated with a crosslinking fixing agent, which is a nonionic alkylamine aqueous solution. Under alkaline conditions, the crosslinking fixing agent is crosslinked with the active groups of the dye molecules and the amide groups of the nylon fibers through covalent bonds. (3) Film-forming and setting treatment: The nylon-ammonia fabric after cross-linking and color fixing treatment is subjected to padding treatment. The padding solution contains a cationic polyamine polymer complex color fixing agent. After high-temperature setting, the cationic polyamine polymer complex color fixing agent is cross-linked in situ on the fiber surface to form a continuous protective film.

[0009] Another technical solution adopted in this invention is to provide a nylon-methylene fabric prepared by a method for improving the storage color fastness of nylon-methylene fabric.

[0010] The beneficial effects of this invention are as follows: This invention constructs a dual synergistic mechanism of cross-linking fixation treatment + film-forming and setting treatment. First, after dyeing nylon-amylon fabric with acidic reactive dyes during the dyeing stage, a nonionic alkylamine aqueous solution is used as a cross-linking fixative. Under alkaline conditions, the alkylamine groups in the fixative molecule undergo nucleophilic substitution reactions with the reactive groups of the dye molecules and the amide groups of the nylon fiber, forming covalent cross-links and chemically locking the unfixed dye onto the fiber. Second, unlike the conventional "wash-resistant / hydrophilic" process, this application introduces a cationic fixative (CFA) in the film-forming and setting treatment stage. Conventional processes usually exclude such film-forming agents to ensure the fabric's hygroscopicity, but this invention finds that to solve the storage resistance problem, a physical barrier must be constructed on the fiber surface. During the high-temperature setting process, the positively charged polymer of the cationic fixative cross-links on the fiber surface to form a dense, continuous, transparent protective film. While this membrane sacrifices hydrophilicity to some extent, its main function is to prevent external moisture from penetrating into the fiber (preventing dye hydrolysis) and to physically restrict the thermal movement of dye molecules (preventing thermal migration). This invention, through a barrier-and-stabilize process design, specifically addresses the technical problem of color change in nylon-spandex fabrics during storage in high-temperature and high-humidity environments.

[0011] This invention works synergistically from two different dimensions: chemical bonding and physical barrier, so that dye molecules cannot desorb from the fiber or migrate outward under high temperature and high humidity storage conditions, thereby significantly improving the storage color fastness of nylon-spandex fabrics (up to grade 4-5) and effectively solving the technical problem of color change and staining of dark nylon-spandex fabrics during long-term storage. Attached Figure Description

[0012] Figure 1 A comparison chart showing the color fastness test results of dyed fabrics from Example 1 and Comparative Example 1, which are specific embodiments of the present invention. Figure 2 This is a comparison chart showing the color fastness test results of the dyed fabrics of Example 2 and Comparative Example 2, which are specific embodiments of the present invention. Detailed Implementation

[0013] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0014] The key concept of this invention is that the existing color fastness process is like making a "bulletproof vest" for clothes, focusing on resisting external attacks (such as washing and friction), while the storage color fastness process of this invention is like making a "vacuum package" for dyes, focusing on internal stability and isolation (preventing the dye from escaping or deteriorating).

[0015] This invention organically combines "chemical bond cross-linking fixation" with "physical membrane barrier protection," which differs from conventional color-fixing processes that rely solely on ionic bonds, and also from single physical barrier schemes that use waterproofing agents to form hydrophobic layers. This invention works synergistically from two different dimensions: chemical bonding and physical barrier, ensuring that dye molecules cannot desorb from the fiber or migrate outwards under high temperature and high humidity storage conditions. This significantly improves the storage color fastness of nylon-spandex fabrics (up to grade 4-5), effectively solving the technical problem of color change and staining in dark-colored nylon-spandex fabrics during long-term storage.

[0016] Specifically: First, acidic reactive dyes that are covalently bonded to nylon fibers are selected, ensuring the chemical stability of the dyes and their strong binding force to the fibers from the source. The acidic reactive dye molecules contain special active groups that can form covalent bonds with the amino and amide groups of nylon fibers, resulting in a binding force far stronger than that of conventional acid dyes, which rely on ionic bonds and van der Waals forces. Simultaneously, their chemical structure is stable and inert, making them less prone to hydrolysis in humid and hot environments, thus ensuring the color stability and storage fastness of the dyes from the source.

[0017] Secondly, in the post-processing steps, cross-linking fixation treatment (which allows the cross-linking fixative to lock the unfixed dye onto the fiber through covalent bonds), washing treatment (to clean the surface of floating dye), and neutralization treatment (to adjust the pH of the fiber surface) are carried out in sequence. These three steps work together to achieve efficient fixation of unfixed dye and thorough removal of floating dye. The effects of the sequence of cross-linking and color-fixing treatment (FIX) followed by washing and cleaning (WFE): FIX (color fixation): First, nonionic alkylamines react with the dye and fiber to cross-link, forcibly fixing any unfixed dyes that haven't yet bonded to the fiber. WFE (washing): After the dyes are fixed, WFE is used to wash away any remaining surface dyes that cannot be removed. Because the dyes have already cross-linked, they will not be washed away by WFE at this stage.

[0018] If the order is reversed (WFE first, then FIX): Unfixed dyes will be washed away: During the WFE cleaning step, those "unfixed dyes" that have not yet bound to the fibers are physically unstable and will be washed off by the WFE as "floating dye" or impurities, and discharged with the wastewater. FIX has no material to fix: When the subsequent FIX fixing step is performed, the dyes that should have been cross-linked and fixed have already been lost. FIX loses its target and cannot perform its cross-linking and fixing function. The final consequence: The total amount of dye on the fabric decreases (becomes lighter), and a large amount of dye is not chemically locked. In subsequent storage or immersion tests, the remaining unfixed dyes are highly susceptible to migration or hydrolysis, resulting in a significant deterioration in storage fastness and water fastness.

[0019] Finally, contrary to the industry's technical bias of "avoiding the use of film-forming cationic fixing agents in the setting stage to avoid affecting hydrophilicity," a cationic film-forming fixing agent is introduced into the setting process for high-temperature padding and setting, which cross-links on the fiber surface to form a dense, continuous, transparent protective film. This effectively prevents dye molecules from migrating outward and external moisture from penetrating through physical barriers.

[0020] This invention provides a method for improving the storage color fastness of nylon-spandex fabrics, comprising the following steps: (1) Dyeing: Acid reactive dyes are used to dye nylon-spandex fabrics; (2) Crosslinking and fixing treatment: The dyed nylon and urethane fabric is treated with a crosslinking fixing agent, which is a nonionic alkylamine aqueous solution. Under alkaline conditions, the crosslinking fixing agent is crosslinked with the active groups of the dye molecules and the amide groups of the nylon fibers through covalent bonds. (3) Film-forming and setting treatment: The nylon-ammonia fabric after cross-linking and color fixing treatment is subjected to padding treatment. The padding solution contains a cationic polyamine polymer complex color fixing agent. After high-temperature setting, the cationic polyamine polymer complex color fixing agent is cross-linked in situ on the fiber surface to form a continuous protective film.

[0021] Furthermore, in the above-mentioned method for improving the storage fastness of nylon-spandex fabrics, the process conditions for the cross-linking and color-fixing treatment in step (2) are: 0.3g / L-1.0g / L caustic soda, 0.5g / L-2.0g / L cross-linking color-fixing agent, and treatment at 75℃-85℃ for 20min.

[0022] As described above, caustic soda is used to adjust the pH of the system to the alkaline range (usually pH 10-11) to activate the reactivity of the alkylamine groups in the cross-linking fixing agent FIX molecule, so that the amine groups of FIX can undergo nucleophilic substitution reactions with the active groups of the dye molecules (such as halogen, vinyl sulfone, etc.) and the amide groups of nylon fibers to form covalent bonds; the concentration of the cross-linking fixing agent is 0.5g / L-2.0g / L to ensure that there are sufficient active functional groups participating in the reaction without excessive residue; the treatment conditions of 75℃-85℃ for 20min provide suitable activation energy for the cross-linking reaction and ensure that the reaction is fully completed. If the temperature or time is lower than this range, the cross-linking will be insufficient, resulting in insufficient storage fastness; if the temperature is higher than this range, the fabric hand feel may be affected by excessive cross-linking.

[0023] Furthermore, in the above-mentioned method for improving the storage color fastness of nylon-spandex fabrics, the high-temperature setting temperature in step (3) of the film-forming and setting treatment is 150℃-170℃ and the time is 60s.

[0024] As described above, the temperature range of 150℃-170℃ ensures that the polyamine active functional groups in the fixing agent molecules obtain sufficient activation energy to undergo intermolecular cross-linking reactions and form a dense and continuous three-dimensional network protective film. At the same time, the upper limit of the temperature is controlled at 170℃ to avoid the spandex fiber from losing strength and elasticity due to overheating.

[0025] Furthermore, in the above-mentioned method for improving the storage color fastness of nylon-spandex fabrics, step (2) after crosslinking and color fixing treatment also includes washing and neutralization treatment.

[0026] As described above, the above-mentioned limitations require that after the color fixation treatment, the following steps must be performed: cleaning and neutralization. First, cross-linking color fixation is performed to chemically lock the unfixed dye onto the fiber through covalent bonds. Then, cleaning is performed to remove surface floating dye. At this point, the dye will not be washed away because it has been fixed by covalent bonds. Finally, neutralization is performed to eliminate alkaline residue on the fiber surface. This sequence ensures that the total amount of dye is retained to the maximum extent while being firmly locked by chemical bonds, thus building a solid chemical bonding foundation for subsequent film formation and shaping.

[0027] Furthermore, in the above-mentioned method for improving the storage color fastness of nylon-spandex fabrics, the process conditions for the washing treatment are: 0-2.0 g / L of soda ash, 1.0 g / L-2.0 g / L of the washing agent, and treatment at 40℃-60℃ for 20 min. The washing agent includes surfactants and dye adsorbents.

[0028] As described above, in the above-mentioned limitations, the surfactant component in the detergent WFE removes and stably disperses the floating dye from the fiber surface by reducing surface tension and emulsifying, while the dye adsorbent component captures the removed dye molecules to prevent them from re-adhering; soda ash provides a weakly alkaline environment (pH 8-9) to enhance the emulsification and dispersion efficiency of the surfactant; ensuring that the floating dye is fully removed without damaging the fixed dye.

[0029] Furthermore, in the above-mentioned method for improving the storage fastness of nylon-spandex fabrics, the process conditions for the neutralization treatment in the post-treatment of step (2) are: acetic acid 0.5g / L, treatment at 30℃-50℃ for 20min.

[0030] As described above, after the two alkaline treatments of cross-linking fixation and washing, the residual caustic soda and soda ash on the fiber surface and inside cause the pH to be too high. Acetic acid is a weak organic acid that can adjust the pH of the fiber surface to the weakly acidic range (pH 4-5), avoiding the alkaline residue from causing subsequent CFA molecules to be unstable or hydrolyzed, affecting the film formation effect, and preventing residual alkali from catalyzing the hydrolysis of dyes during long-term storage.

[0031] Furthermore, in the above-mentioned method for improving the storage fastness of nylon-spandex fabrics, in step (1) of dyeing, a dyeing accelerator is added to dye the nylon-spandex fabric, wherein the dyeing accelerator is RDL and / or calcium chloride.

[0032] As described above, RDL is a compound of nonionic ethoxy fatty amine and special active ingredients, and calcium chloride is an inorganic salt dyeing accelerator. Both can effectively improve the affinity of acid dyes for nylon fibers, i.e., "direct dyeing," so that the dye preferentially and firmly adsorbs onto the nylon fibers during the dyeing process rather than physically adhering to the spandex surface. Spandex itself has few dyeing seats and weak affinity for dyes, but after the dye physically adheres to the spandex surface, it will slowly release and migrate during storage, causing staining. The dyeing accelerator solves the problem of spandex staining from the source of dyeing by increasing the affinity of dyes for nylon and reducing the physical adhesion of dyes to spandex.

[0033] Furthermore, in the above-mentioned method for improving the storage fastness of nylon-spandex fabrics, in step (1) of dyeing, a leveling agent is added to dye the nylon-spandex fabrics, and the leveling agent is an amphoteric surfactant.

[0034] As described above, the zwitterionic surfactant molecules contain both cationic and anionic groups, exhibiting affinity for both acid dyes and nylon fibers. During the dyeing process, the cationic groups combine with the anionic dye to form unstable complexes, thus delaying dyeing (slow dyeing). The anionic groups can also pull the unevenly dyed dye off the fiber and redistribute it (transfer dyeing). Through the synergistic effect of slow dyeing and transfer dyeing, the dye is evenly distributed on the nylon fiber. This avoids the defects of dyeing defects such as color spots and discoloration that are easily caused by simple cationic or anionic leveling agents. It is especially suitable for nylon-spandex blended fabrics where the dyeing rates of nylon and spandex differ significantly.

[0035] Furthermore, in the above method for improving the storage color fastness of nylon-spandex fabrics, the dyeing step employs a gradient temperature increase, and the process conditions for the gradient temperature increase include: Increase the temperature from 30℃-40℃ to 50℃-60℃ at a rate of 0.5℃ / min-1.0℃ / min, and hold for 10 minutes; The temperature was increased from 50℃-60℃ to 85℃-95℃ at a rate of 0.5℃ / min-0.8℃ / min. The temperature was increased from 85℃-95℃ to 95℃-100℃ at a rate of 0.8℃ / min-1.2℃ / min and held for 40 minutes; the temperature was then decreased from 95℃-100℃ to 60℃ at a rate of 1.5-2.0℃ / min.

[0036] As described above, the heating curve allows the acidic reactive dye to be uniformly adsorbed at low temperatures and fully penetrate the nylon fiber at high temperatures, which is suitable for the process of this invention. The heating rate should be suitable, neither too fast nor too slow. Too fast a rate will result in uneven dye uptake, while too slow a rate will affect production efficiency.

[0037] Another technical solution adopted in this invention is to provide a nylon-methylene fabric prepared by the above-mentioned method for improving the storage color fastness of nylon-methylene fabric.

[0038] In a specific embodiment of this invention, the nylon-spandex fabric is a blend of nylon and spandex, and may also contain polyester. The test colors of the fabric are black or bright blue. This invention does not impose any particular restrictions on the material of the fabric, but it is more suitable for dark-colored fabrics made from two-component or three-component blends of nylon / spandex. Typically, the dyeing rates of nylon and spandex differ significantly, easily leading to uneven dyeing and spandex staining, requiring optimization using this process. Therefore, the fabric can be either a nylon-spandex blend or a nylon-polyester-spandex blend. Regarding the test colors, from the perspective of typical dark dyeing, black or bright blue are possible, but this does not represent a limitation on the dyeing method of this invention. For example, the test colors can be black, bright blue, navy blue, etc.

[0039] In a specific embodiment of the present invention, the acidic reactive dyes used in the dyeing step include Nylon Reactive Yellow M-RG, Nylon Reactive Red M-2B, Nylon Reactive Black M, and Nylon Reactive Brilliant Blue M-3R (manufacturer: Green Textile). Acidic reactive dyes have a more stable and inert chemical structure, are less prone to hydrolysis in humid and hot environments, and are less likely to decompose or deteriorate during long-term storage, thus maintaining color vibrancy and stability. Furthermore, they have a very strong binding force with nylon fibers, making it difficult for dye molecules to migrate from the fiber interior to the surface during storage, greatly improving storage fastness. The amount of dye used should be appropriate; too much or too little will result in a darker color and wasted dye, while too little will lead to insufficient color and lower fastness.

[0040] The auxiliary agent formulation includes: leveling agent B-PAX 0.5-1.0g / L (manufacturer: Weigeshi / Lvfang), spandex anti-staining agent RDL 2.0-4.0g / L (manufacturer: Lvfang), calcium chloride 0-6g / L, caustic soda 0.3-1.0g / L, nylon fixing agent FIX 0.5-2.0g / L (manufacturer: Lvfang), soda ash 0-2.0g / L, water fastness improver WFE 1.0-2.0g / L (manufacturer: Lvfang), HAC 0.5g / L, and cationic fixing agent CFA 10-30g / L (manufacturer: Lvfang). B-PAX is a compound of zwitterionic surfactants, which acts as a leveling agent; RDL is a compound of nonionic ethoxylated fatty amines and special active ingredients, which mainly acts as a dyeing promoter, can improve the affinity of acid reactive dyes, enhance direct dyeing, significantly reduce staining of spandex, and effectively improve dyeing fastness and depth; FIX, a nonionic alkylamine aqueous solution, cross-links with dye molecules and nylon fibers through covalent bonds to fix unfixed dyes; WFE is a compound of surfactants and dye adsorbents, used to clean surface floating dyes; CFA is a cationic polyamine-type polymer complex that forms a dense protective film on the fiber surface during setting.

[0041] In a specific embodiment of the present invention, the crosslinking and color-fixing treatment, washing treatment, and neutralization treatment steps can be as follows: ① Sodium carbonate 0.3-1.0 g / L, nylon color-fixing agent FIX 0.5-2.0 g / L, 75-85℃, 20 min (liquor ratio 1:10-15); ② Soda ash 0-2.0 g / L, water fastness improver WFE 1.0-2.0 g / L, 40-60℃, 20 min (liquor ratio 1:10-15); The liquor ratio is the mass ratio of liquid to fabric during the dyeing process. A liquor ratio of 1:10-15 can ensure uniform dispersion of dye and full wetting of fibers, which is suitable for the dyeing process of the present invention. ③ HAC 0.5 g / L, 30-50℃, 20 min (liquor ratio 1:10-15). Sodium hydroxide flakes are mainly used to adjust pH; FIX cross-links with dye molecules and nylon fibers through covalent bonds, fixing the unfixed dye, improving storage fastness and water fastness, and has high heat setting stability; WFE treatment further cleans the surface floating color and improves water fastness; HAC is used for neutralization.

[0042] The specific film-forming and setting process can be as follows: cationic fixing agent CFA 10-30g / L, one dip and one pad, 150-170℃, 60s. In the cationic fixing agent CFA dip-pad-high temperature setting process: after the fabric is dipped in the cationic fixing agent working solution, the positively charged fixing agent molecules will be rapidly and uniformly adsorbed on the fiber surface and combined with the dye anions through ionic bonds; then it enters the high temperature setting machine, where the water evaporates and the polymer in the fixing agent undergoes a cross-linking reaction, forming a dense, continuous, and strong transparent protective film on the fiber surface. This high-performance film can effectively prevent dye molecules from dissolving and migrating outward, thereby effectively improving storage fastness.

[0043] The colorfastness rating after drying in this invention is evaluated according to the method in GB / T 32008-2015 "Textiles - Tests for Colorfastness to Storage". In this standard, the sample cards are divided into nine grades: Grade 1, Grade 1-2, Grade 2, Grade 2-3, Grade 3, Grade 3-4, Grade 4, Grade 4-5, and Grade 5. The higher the grade, the lighter the color of the sample card, indicating less dissolved dye and higher colorfastness of the dyed fabric.

[0044] Example 1 A method for improving the storage color fastness of nylon-spandex fabric (black nylon-spandex fabric) includes the following steps: (1) Dyeing: The nylon fabric is dyed with acid dyes according to the following dyeing formula; the dyeing formula is shown in Table 1.

[0045] Table 1

[0046] Bath ratio: 1:10-15; Step (1) dyeing employs a gradient temperature increase, the process conditions of which include: Increase the temperature from 30-40℃ to 50-60℃ at a rate of 0.5-1.0℃ / min, hold at 50-60℃ for 10 minutes, increase the temperature from 50-60℃ to 85-95℃ at a rate of 0.5-0.8℃ / min, increase the temperature from 85-95℃ to 95-100℃ at a rate of 0.8-1.2℃ / min, hold at 40 minutes, and decrease the temperature from 98℃ to 60℃ at a rate of 1.5-2.0℃ / min. After slow cooling, wash with water at room temperature.

[0047] Staining temperature: 100℃, 40 min; (2) Post-treatment: including color fixing treatment, rinsing treatment and neutralization treatment in sequence; Specific post-processing (R / C) techniques include: ① 0.5 g / L caustic soda, 1.0 g / L nylon fixing agent FIX, 80℃, 20 min (liquor ratio 1:15); ② Soda ash 2.0g / L, water fastness improver WFE 2.0g / L, 50℃, 20min (liquor ratio 1:15); ③HAC 0.5g / L, 50℃, 20min (liquor ratio 1:15); (3) Setting: The dyed nylon-spandex fabric is padded with a cationic fixing agent with film-forming function, and then set at high temperature. The specific setting process conditions are as follows: Cationic fixing agent CFA 30g / L, one dip and one pad, 160℃, 60s; Comparative Examples 1 and 2 are set up with the same conditions as in Example 1, except that: (1) Conditioning conditions for Comparative Example 1: After dyeing and removing from the vat, the color-fixing agent was not added and the color was fixed directly after dehydration.

[0048] (2) Conditioning conditions for Comparative Example 2: Immerse once in 15 g / L cationic fixing agent HCF, press once with a rolling mill, and fix at 160°C for 60 s.

[0049] (3) Setting conditions of Example 1: Immerse once in 30g / L cationic fixing agent CFA, press once with a rolling mill, and set at 160℃ for 60s.

[0050] The color fastness of the dyed fabrics produced by the dyeing processes of Example 1, Comparative Example 1, and Comparative Example 2 was tested, and the results are as follows: Figure 1 As shown in Table 1. Color fastness testing conditions: temperature 70℃±2, relative humidity 80%±5, time 3h. Among them, Figure 1 The items in Table 1 correspond as follows: Untested cotton fabric: Cotton fabric raw material; After testing, the color fastness of the dyed nylon-spandex fabric was tested using single-fiber cotton. Color fastness testing was performed on the dyed nylon-spandex fabrics after testing under various finishing conditions. Multi-fiber test results: Color fastness of dyed nylon-spandex fabrics was tested using multi-fibers such as acetate fiber, cotton, nylon, polyester, acrylic fiber, and wool. Single fiber staining rating: Staining rating of cotton single fibers on dyed nylon / spandex fabrics; Multi-fiber staining rating: Staining rating of dyed nylon and spandex fabrics using multiple fibers such as acetate fiber, cotton, nylon, polyester, acrylic fiber, and wool; Table 1

[0051] Table 1 above uses monofiber and multifiber as a control for the lining: Simulate specific mixed washing scenarios: When the test sample is a cotton fabric or a cotton-based blend / interweave fabric, using a cotton lining can simulate a common household scenario where it is washed together with pure cotton fabrics, thereby assessing the risk of color staining in this situation.

[0052] Targeted evaluation: Single-fiber lining can more specifically evaluate the staining ability of a sample on a specific fiber (such as cotton), and the results are closer to the actual situation of washing with similar fabrics in actual use.

[0053] The reasons for using multifiber fabric (multifiber lining) are as follows: Comprehensive evaluation in one go: Multifiber fabric integrates multiple different fibers (such as acetate fiber, cotton, nylon, polyester, acrylic, wool, etc.) on a single piece of fabric. In a single test, the staining of the sample on these six different fibers can be observed and evaluated simultaneously, greatly improving testing efficiency.

[0054] Finding the worst performance: Because different fibers have different adsorption capacities for dyes (for example, nylon and wool readily adsorb certain dyes), multifiber fabric can reveal the worst staining grade of a sample among all tested fibers in one test, and is therefore considered a more rigorous and comprehensive testing method.

[0055] Compliance with standards: Depending on the testing standards, multifiber fabric is a specified standard dyed lining. For example, ISO standards typically require the use of DW multifiber fabric, while AATCC standards often use NO 10# multifiber fabric.

[0056] The above Figure 1 The test results in Table 1 are analyzed as follows: Comparative Example 1 (without color-fixing agent): Visually, the cotton monofibers may show slight black staining after testing. The multifiber lining after testing shows obvious gray / light-colored traces. This means that during the testing process, black dye was detached from the main fabric and transferred to the multifiber lining, causing significant discoloration of the lining.

[0057] Comparative Example 2 (Cationic fixing agent HCF 15g / L): The color condition of the single-fiber and multi-fiber linings is very similar to that of Comparative Example 1, with obvious gray traces still present. Comparative Example 2 does not show a significant improvement over Comparative Example 1 visually.

[0058] Example 1 (Catonic fixing agent CFA 30g / L): The multifiber lining in Example 1 appeared the whitest and cleanest. Compared to the previous two groups, it showed the least degree of discoloration, indicating that the amount of dye detached and adhered to the lining was minimal.

[0059] The staining rating of monofibril cotton in Comparative Example 2 was 3-4, and the staining rating of multifibril cotton was 3-4. After the fixing agent was replaced by CFA in Example 1 instead of HCF in Comparative Example 2, the staining rating of monofibril cotton and multifibril cotton reached the highest level of 4.

[0060] Visually, after testing, the cotton fabric showed almost no obvious black staining in both single-fiber and multi-fiber fabrics (as the staining rating was close to the highest level), indicating that the CFA color-fixing effect was the most significant.

[0061] Example 2 A method for improving the storage color fastness of nylon-spandex fabric (bright blue nylon-spandex fabric) includes the following steps: (1) Dyeing: Acid dyes with the following dyeing formulas are used to dye nylon-spandex fabrics; the dyeing formulas are shown in Table 2; Table 2

[0062] Bath ratio: 1:10-15 The dyeing process in step (1) employs a gradient temperature increase, and the process conditions for the gradient temperature increase include: Increase the temperature from 30-40℃ to 50-60℃ at a rate of 0.5-1.0℃ / min, hold at 50-60℃ for 10 minutes, increase the temperature from 50-60℃ to 85-95℃ at a rate of 0.5-0.8℃ / min, increase the temperature from 85-95℃ to 95-100℃ at a rate of 0.8-1.2℃ / min, hold at 30 minutes, and decrease the temperature from 98℃ to 60℃ at a rate of 1.5-2.0℃ / min. After slow cooling, wash with water at room temperature.

[0063] Staining temperature: 100℃, 30 min (2) Post-treatment: including color fixing treatment, rinsing treatment and neutralization treatment in sequence; Specific post-processing (R / C) techniques include: ① 0.5 g / L caustic soda, 2.0 g / L nylon fixing agent FIX, 85℃, 20 min (liquor ratio 1:10); ② Soda ash 2.0g / L, water fastness improver WFE 2.0g / L, 60℃, 20min (liquor ratio 1:10); ③ HAC 0.5g / L, 30℃, 20min (liquor ratio 1:10); (3) Setting: The dyed nylon-ammonia fabric is impregnated and then set at high temperature using a cationic fixing agent with film-forming function.

[0064] The specific process conditions for finalization are as follows: Cationic fixing agent CFA 30g / L, one dip and one pad, 160℃, 60s; Comparative Examples 3 and 4 were set up, and the steps (1) and (2) of Comparative Examples 3 and 4 were the same as those in Example 1, except that: (1) Conditioning conditions for comparative example 3: After dyeing and removing from the vat, the dyeing was directly fixed after dehydration.

[0065] (2) Conditioning conditions for Comparative Example 4: Immerse once in 15 g / L cationic fixing agent HCF, press once with a rolling mill, and fix at 160°C for 60 s.

[0066] (3) Setting conditions in Example 2: Immerse once in 30 g / L cationic fixing agent CFA, press once with a rolling mill, and set at 160°C for 60 s.

[0067] The color fastness of the dyed fabrics produced by the dyeing processes of Example 2, Comparative Examples 3 and 4 was tested, and the results are as follows: Figure 2 As shown in Table 2. Color fastness testing conditions: temperature 70℃±2, relative humidity 80%±5, time 3h. Figure 2 The items in Table 2 correspond as follows: Untested cotton fabric: only cotton fabric raw material; After testing, the color fastness of the dyed nylon-spandex fabric was tested using single-fiber cotton. Color fastness testing was performed on the dyed nylon-spandex fabrics after testing under various finishing conditions. Multi-fiber test results: Color fastness of dyed nylon-spandex fabrics was tested using multi-fibers such as acetate fiber, cotton, nylon, polyester, acrylic fiber, and wool. Single fiber staining rating: Staining rating of cotton single fibers on dyed nylon / spandex fabrics; Multi-fiber staining rating: Staining rating of dyed nylon and spandex fabrics using multiple fibers such as acetate fiber, cotton, nylon, polyester, acrylic fiber, and wool; Table 2

[0068] The above Figure 2 The test results in Table 2 are analyzed as follows: Comparative Example 3 (without color-fixing agent): Visually, slight blue staining was observed on both the single-fiber and multi-fiber cotton linings after the test.

[0069] This means that during the test, the blue dye detached from the main fabric and stained the multifiber lining, causing the lining to change color significantly.

[0070] Comparative Example 4 (Cationic fixing agent HCF 15g / L): The color of the single-fiber and multi-fiber linings is very similar to that of Comparative Example 1, with obvious traces of bluish discoloration. Comparative Example 4 does not show a significant improvement over Comparative Example 3.

[0071] Example 2 (Catonic fixing agent CFA 30g / L): The multifiber lining in Example 2 appeared the whitest and cleanest. Compared to the previous two groups, it showed the least degree of discoloration, indicating that the amount of dye detached and adhered to the lining was minimal.

[0072] The staining rating of monofiber cotton in Comparative Example 4 was 3-4, and the staining rating of multifiber cotton was 3-4. After the fixing agent was replaced by CFA in Example 2 instead of HCF in Comparative Example 2, the staining rating of monofiber cotton and multifiber cotton reached the highest level of 4.

[0073] Visually, after testing, there was almost no obvious blue staining on the single and multi-fiber cotton fabrics (because the staining rating was close to the highest level), indicating that the CFA's effect on "fixing the color of brilliant blue dye on cotton and multi-fiber fabrics" was the most significant.

[0074] As can be seen from the above, the methods of the present invention for improving the storage fastness of nylon-spandex fabrics in Examples 1 and 2, by selecting more stable acid reactive dyes (bright fastness series), combined with RDL dyeing to reduce spandex staining, FIX color-fixing agent crosslinking to fix unfixed dyes, WFE cleaning of surface floating color, and then CFA padding to form a dense protective film on the fiber surface, can effectively improve the storage fastness and water fastness of nylon-spandex fabrics.

[0075] Furthermore, the acidic reactive dye (bright fastness) selected in this invention has a more stable and inert chemical structure, is not prone to hydrolysis in humid and hot environments, and the dye molecules themselves are not easily decomposed or deteriorated during long-term storage, thus maintaining the brightness and stability of the color; and the binding force between it and nylon fiber is very strong, making it difficult for dye molecules to migrate from the inside of the fiber to the surface during storage, which greatly improves the storage fastness.

[0076] Adding RDL to the dyeing process mainly promotes dyeing, increases the affinity of acid reactive dyes, enhances direct dyeing properties, significantly reduces staining of spandex, and effectively improves color fastness and depth. Nylon fixing agent FIX cross-links with dye molecules and nylon fibers through covalent bonds, fixing unfixed dyes, improving storage fastness and water fastness, and exhibiting high heat-setting stability. Water fastness enhancer WFE further cleans surface loose dye. During setting, CFA forms a dense protective film on the fiber surface, effectively preventing dye molecules from dissolving and migrating outwards.

[0077] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for improving the storage color fastness of nylon-spandex fabrics, characterized in that, Includes the following steps: (1) Dyeing: Acid reactive dyes are used to dye nylon-spandex fabrics; (2) Crosslinking and fixing treatment: The dyed nylon and urethane fabric is treated with a crosslinking fixing agent, which is a nonionic alkylamine aqueous solution. Under alkaline conditions, the crosslinking fixing agent is crosslinked with the active groups of the dye molecules and the amide groups of the nylon fibers through covalent bonds. (3) Film-forming and setting treatment: The nylon-ammonia fabric after cross-linking and color fixing treatment is subjected to padding treatment. The padding solution contains a cationic polyamine polymer complex color fixing agent. After high-temperature setting, the cationic polyamine polymer complex color fixing agent is cross-linked in situ on the fiber surface to form a continuous protective film.

2. The method for improving the storage fastness of nylon-spandex fabrics according to claim 1, characterized in that, The process conditions for the cross-linking and color-fixing treatment in step (2) are: 0.3g / L-1.0g / L caustic soda, 0.5g / L-2.0g / L cross-linking color-fixing agent, and treatment at 75℃-85℃ for 20min.

3. The method for improving the storage color fastness of nylon-spandex fabrics according to claim 1, characterized in that, The high-temperature setting temperature in step (3) of the film-forming and setting process is 150℃-170℃, and the time is 60s.

4. The method for improving the storage color fastness of nylon-spandex fabrics according to claim 1, characterized in that, The step (2) after cross-linking and color fixing treatment also includes a cleaning treatment and a neutralization treatment.

5. The method for improving the storage color fastness of nylon-spandex fabrics according to claim 4, characterized in that, The cleaning process conditions are as follows: soda ash 0-2.0 g / L, cleaning agent 1.0 g / L-2.0 g / L, treatment at 40℃-60℃ for 20 min, the cleaning agent includes surfactant and dye adsorbent.

6. The method for improving the storage color fastness of nylon-spandex fabrics according to claim 5, characterized in that, The neutralization process conditions in the post-treatment of step (2) are: acetic acid 0.5 g / L, 30℃-50℃ for 20 min.

7. The method for improving the storage color fastness of nylon-spandex fabrics according to claim 1, characterized in that, In step (1) of dyeing, a dyeing accelerator is added to dye the nylon-ammonia fabric. The dyeing accelerator is RDL and / or calcium chloride.

8. The method for improving the storage color fastness of nylon-spandex fabrics according to claim 1, characterized in that, In step (1) of the dyeing process, a leveling agent is added to dye the nylon-ammonia fabric. The leveling agent is an amphoteric surfactant.

9. The method for improving the storage fastness of nylon-spandex fabrics according to claim 1, characterized in that, The dyeing step employs a gradient temperature increase, and the process conditions for the gradient temperature increase include: Increase the temperature from 30℃-40℃ to 50℃-60℃ at a rate of 0.5℃ / min-1.0℃ / min, and hold for 10 minutes; The temperature was increased from 50℃-60℃ to 85℃-95℃ at a rate of 0.5℃ / min-0.8℃ / min. The temperature was increased from 85℃-95℃ to 95℃-100℃ at a rate of 0.8℃ / min-1.2℃ / min and held for 40 minutes; the temperature was then decreased from 95℃-100℃ to 60℃ at a rate of 1.5-2.0℃ / min.

10. A nylon-spandex fabric, characterized in that, It is prepared by the method for improving the storage color fastness of nylon-spandex fabrics according to any one of claims 1 to 9.

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