Water-ethanol synergistic flame-retardant polyester fiber non-aqueous dyeing method

Abstract

The invention belongs to the field of textile chemistry, and particularly relates to a water-ethanol synergistic flame-retardant polyester fiber non-aqueous dyeing method. The invention relates to a water-ethanol synergistic flame-retardant polyester fiber non-aqueous dyeing method, which comprises: S1, dyeing: compounding water and ethanol to form an auxiliary agent, and placing the auxiliary agent in an isohexadecane non-aqueous dyeing system containing a disperse dye to form a dyeing liquid; immersing flame-retardant polyester fibers into the dye liquor for dyeing; on the basis of the mass of 1 g of the fiber, the use amount of the isohexadecane is 10-60 mL, the use amount of the auxiliary agent is 0.25-2 mL, and the volume ratio of the water to the ethanol is 1: 9-9: 1; s2, soaping: after the dyeing step is completed, putting the dyed fibers into soaping liquid for soaping so as to remove flooding. The method has the characteristics of energy conservation, environmental protection, no pollution, good leveling property of the dyed fiber, good color fastness and the like.

Description

Technical Field

[0001] This invention belongs to the field of textile chemistry, and specifically relates to a non-aqueous dyeing method for flame-retardant polyester fibers with synergistic effects of water and ethanol. Background Technology

[0002] Flame-retardant polyester fiber is widely used in key areas such as clothing, vehicle interiors and special protective equipment due to its excellent physical properties and safety characteristics. However, its dyeing process, especially the traditional water bath dyeing, has long faced three major challenges: (1) Damage to flame retardant performance: Traditional dyeing auxiliaries (such as dispersants) may react adversely with the flame retardants in the fiber, resulting in a decrease in the flame retardant effect of the fiber; (2) Low dyeing efficiency: The dense structure of flame-retardant polyester fiber makes it difficult for dyes to penetrate, resulting in low dyeing rate and poor uniformity; (3) Serious environmental pollution: Water bath dyeing generates a large amount of dyeing wastewater containing high concentrations of difficult-to-degrade auxiliaries, which puts enormous pressure on the environment.

[0003] To address these challenges, non-aqueous dyeing techniques, especially atmospheric pressure organic solvent dyeing, have become an important research direction in the industry due to their water-saving, energy-saving, and potential environmental advantages. Among many organic solvents, isohexadecane stands out for its high chemical inertness, low toxicity, and ease of recycling, and is considered a non-aqueous dyeing medium with great application potential.

[0004] However, existing technologies for dyeing polyester using isohexadecane encounter a bottleneck: isohexadecane is a typical non-polar solvent, and it has almost no ability to cause swelling in highly polar polyester fibers. This results in dye molecules being unable to effectively penetrate the fiber interior, often leading to extremely low dye uptake and insufficient color depth, failing to meet the requirements for commercial applications. Although some technologies have attempted to improve this by adding a single polar auxiliary agent (such as pure water or pure alcohol), the results remain unsatisfactory: pure water and isohexadecane are immiscible, making it difficult to form a stable system; while pure alcohols can partially solubilize, their swelling effect on the fiber is limited, and it remains difficult to achieve both dyeing depth and levelness.

[0005] Therefore, how to effectively address the inherent defect of insufficient swelling capacity of polyester fibers while maintaining the environmental advantages of the isohexadecane system, and achieve efficient dyeing and uniform distribution, has become an urgent technical problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a non-aqueous dyeing method for flame-retardant polyester fibers with synergistic effects of water and ethanol. This method is characterized by energy saving, environmental protection and no pollution, and good uniformity and color fastness of the dyed fibers.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A non-aqueous dyeing method for flame-retardant polyester fibers with synergistic effects of water and ethanol, the method comprising the following steps:

[0009] S1. Dyeing: Water and ethanol are mixed to form an auxiliary agent, which is then placed in a non-aqueous dyeing system containing disperse dyes and isohexadecane to form a dye solution; flame-retardant polyester fibers are then immersed in the dye solution for dyeing.

[0010] The amount of disperse dye used is 0.1%-8% owf.

[0011] Based on 1g fiber mass, the amount of isohexadecane used is 10-60 mL, the amount of auxiliary agent used is 0.25-2 mL, and the volume ratio of water to ethanol is 1:9 to 9:1.

[0012] S2. Soaping: After completing the dyeing step, the dyed fibers are placed in a soaping solution for soaping to remove excess dye.

[0013] In this invention, the auxiliary agent is used to assist the disperse dye in dissolving in isohexadecane and swelling the fiber.

[0014] The core of this invention lies in utilizing the swelling effect of trace amounts of water on fibers and the enhanced solubility of dyes in isohexadecane with ethanol, thereby achieving efficient and uniform dyeing of polyester fibers in isohexadecane. During the dyeing process, trace amounts of water cause the fibers to swell under the influence of temperature, which in turn allows ethanol to carry the dissolved disperse dye into the amorphous region of the fiber, completing the dyeing process. Finally, a soaping solution is prepared for low-temperature soaping to remove excess dye, resulting in uniformly dyed flame-retardant polyester fibers.

[0015] Preferably, the dyeing step in S1 is performed at a temperature of 80~150 ℃ for 10~240 min; the soaping step in S2 is performed at a temperature of 60 ℃~90 ℃ for 15~60 min. In the dyeing process, a dyeing temperature of 110~130 ℃ and a dyeing time of 60~80 min exhibit good dyeing performance.

[0016] Preferably, the temperature of the staining step in S1 is 110~130 ℃ and the time is 60~80 min.

[0017] Preferably, the amount of disperse dye used is 2%-4% owf. When the amount of disperse dye used is 2%-4%, the K / S value is significantly improved and the leveling property is maintained at a good level.

[0018] Preferably, the amount of isohexadecane used is 20-40 mL and the amount of auxiliary agent is 0.5-1 mL, based on 1 g of fiber mass.

[0019] Preferably, the volume ratio of water to ethanol is 7:3 to 9:1. This provides the best overall performance in terms of K / S value and leveling properties. In the optimal case, the volume ratio of water to ethanol is 8:2.

[0020] Preferably, the disperse dye is one or more of the following: Disperse Blue UN-SE 200%, Disperse Red UN-SE 200%, and Disperse Yellow UN-SE 200%.

[0021] Preferably, the bath ratio of flame-retardant polyester fiber to isohexadecane is 1:3 to 1:60. More preferably, it is 1:20 to 1:40.

[0022] Preferably, the soaping solution consists of 2 g / L NaOH, 2 g / L sodium hydrosulfite, and 3 g / L soap flakes.

[0023] Preferably, the dye liquor and flame-retardant polyester fibers are placed in the dye cup of an adjustable sampler; the adjustable sampler heats up to the dyeing temperature at a constant rate and holds the temperature during the dyeing process, while rotating at a constant rate to ensure that the dye is evenly applied to the flame-retardant polyester fibers.

[0024] A flame-retardant polyester fiber is obtained by dyeing as described in this invention. The flame-retardant polyester fiber obtained by this method has a levelness of less than 1.0.

[0025] Compared with the prior art, the present invention achieves the following significant and beneficial technical effects by creatively introducing a "water-ethanol" binary compound additive system:

[0026] 1. Achieving a synergistic effect between water and ethanol overcomes the dyeing challenge of non-polar solvents. The core innovation of this invention lies in the discovery of the synergistic mechanism of water and ethanol in the isohexadecane system. This is not a simple physical mixture, but rather a complementary "dual-channel" synergistic mode: trace amounts of water, as highly polar molecules, preferentially act on polyester fibers at high temperatures, intensifying the movement of their molecular chain segments and generating effective swelling, thus opening channels for dye entry; while ethanol, acting as a "bridge molecule," maintains affinity with non-polar isohexadecane and disperse dyes on one end due to its amphiphilicity, and can smoothly enter the water-swollen fiber microregions on the other end, efficiently "carrying" and transferring the dye into the fiber interior. This synergistic effect solves the technical bottlenecks of isohexadecane's inability to swell fibers and the poor effectiveness of single auxiliaries.

[0027] 2. The dyeing effect is significantly improved, achieving both high color depth and excellent levelness. Comparative data shows that compared with the pure isohexadecane system without auxiliaries (K / S value of only 2.0) and the traditional water bath dyeing system (poor levelness, unevenness as high as 1.46), the fibers obtained by the method of this invention not only have extremely high apparent color depth (K / S value up to 11.96), but also exhibit excellent levelness (unevenness as low as 0.22). This proves that this invention not only solves the problem of "not being able to dye," but also the problem of "uneven dyeing," achieving a perfect unity of dyeing depth and uniformity.

[0028] 3. While achieving excellent dyeing effect, this invention perfectly preserves and amplifies the environmental advantages of non-aqueous dyeing: (1) Recyclable isohexadecane is used as the main medium, which replaces a large amount of water resources from the source; (2) No traditional dispersants or other difficult-to-degrade auxiliaries need to be added during the dyeing process, which significantly reduces the cost and difficulty of subsequent wastewater treatment; (3) The amount of auxiliaries (water and ethanol) used is small, and they are all environmentally friendly and low-cost substances.

[0029] In summary, this invention provides a technically feasible, economically reasonable, and environmentally friendly clean dyeing solution for flame-retardant polyester fibers. Attached Figure Description

[0030] Figure 1 This is a sample image of flame-retardant polyester fiber after being dyed with disperse dye in isohexadecane medium, as shown in Example 1.

[0031] Figure 2 This is an example of SEM images of flame-retardant polyester fibers before and after dyeing with disperse dyes in isohexadecane medium.

[0032] Figure 3 Comparative Example 1: Comparative sample images of flame-retardant polyester fibers dyed with disperse dyes in isohexadecane medium.

[0033] Figure 4 This is a comparison image of flame-retardant polyester fibers in Comparative Example 2 after being dyed with disperse dyes in an aqueous medium. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0035] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0036] Unless otherwise specified, the reagents used in the following examples can be purchased from a regular biochemical reagent store.

[0037] Disperse Blue UN-SE 200%, purchased from Zhejiang Runtu Co., Ltd.;

[0038] Isohexadecane medium, purchased from Guangzhou Chengyi Chemical Co., Ltd., China;

[0039] Flame-retardant polyester fiber, 1.56D×38mm, purchased from Zhuji Yizheng Chemical Fiber Co., Ltd.

[0040] Ethanol was purchased from Zhejiang Tengyu New Material Technology Co., Ltd.

[0041] In the embodiments and comparative examples of this invention, the apparent color depth (K / S value) was measured using a Datacolor SF600X colorimeter. The uniformity of dyeing was evaluated using the unevenness index; a smaller value indicates better uniformity.

[0042] Performance testing methods: The flame-retardant polyester fiber samples obtained in each embodiment were dried and then tested. The K / S value and dyeability were the main indicators for evaluating the dyeing effect, and the testing methods are as follows:

[0043] After the dyed flame-retardant polyester fibers are dried and rehydrated, they are flattened and pressed onto light-transmitting holes. The K / S values ​​at the maximum absorption wavelength at 12 different locations are measured using a colorimeter, and the average value is recorded. The standard deviation of the dyed fabric is calculated from the measured K / S values, and the unevenness of the dyed fabric is calculated according to the following formula. In the formula: S λ λ represents the standard deviation; λ is the maximum absorption wavelength of the corresponding dye, in nm; n is the number of sampling points. The smaller the non-uniformity, the better the leveling performance; the larger the non-uniformity, the worse the leveling performance.

[0044] Example 1 (Best Case):

[0045] This embodiment provides a non-aqueous dyeing method for flame-retardant polyester fibers with synergistic effects of water and ethanol. The specific steps are as follows:

[0046] (1) Preparation of dye solution:

[0047] A water and ethanol are mixed to form an auxiliary agent. The auxiliary agent is placed in an isohexadecane non-aqueous dyeing system containing disperse dye, and the mixture is stirred thoroughly to disperse the dye evenly in the medium, thus forming a dye solution.

[0048] Composition of the dye solution:

[0049] Disperse blue dye UN-SE 200% 0.015 g,

[0050] 15 mL of isohexadecane

[0051] Additive: 500 μL, composed of 400 μL of water and 100 μL of ethanol (volume ratio 8:2).

[0052] (2) Dyeing: Immerse 0.5 g of flame-retardant polyester fiber in the dye solution prepared in step (1) and dye for 60 min at a temperature of 130 ℃.

[0053] (3) Soap washing: The flame-retardant polyester fibers dyed in step (2) were placed in 25 mL of soap washing solution (2 g / L NaOH, 2 g / L sodium hydrosulfite, 3 g / L soap flakes) and washed at 80 ℃ for 15 min. Flame-retardant polyester fiber samples were obtained.

[0054] Comparative Example 1

[0055] The staining method in this embodiment is basically the same as that in Example 1, except that: no auxiliary agent composed of water and ethanol is added in step (1) of this embodiment, and the amount of isohexadecane used is 15 mL.

[0056] Comparative Example 2: Conventional Water Bath Dyeing Process

[0057] The staining method in this embodiment is basically the same as that described in Example 1, except that water is used as the medium. The composition of the dye solution in this embodiment is as follows:

[0058] Disperse blue dye UN-SE 200% 0.015 g,

[0059] 15ml of water

[0060] Dispersant NNO (2g / L), 0.03g.

[0061] The test results of Example 1, Comparative Example 1, and Comparative Example 2 are as follows: Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown in Table 1.

[0062] Table 1. Dyeing effect of flame-retardant polyester fiber under different systems

[0063]

[0064] As shown in Table 1, compared with dyeing without auxiliaries (Comparative Example 1), the method of the present invention (Example 1) can achieve a higher dyeing depth (K / S) while maintaining excellent levelness (uniformity value below 1.0). The average K / S value of the dyed fibers was 11.9653, and the levelness was 0.2240, proving the feasibility of adding auxiliaries to isohexadecane for dyeing. Compared with traditional water-based dyeing (Comparative Example 2), this method greatly improves the uniformity of the dyed fibers and avoids the use of dispersants, reducing the generation of dyeing wastewater. The color fastness to soap washing test showed that the color fastness was all in the range of 4-5. After dyeing with isohexadecane, the maximum weight loss rate temperature of the flame-retardant polyester fibers did not change significantly, proving that isohexadecane has little effect on the thermal stability of the flame-retardant polyester fibers.

[0065] also, Figure 1 The exhibition showcased flame-retardant polyester fibers, which, after dyeing, exhibit a deep blue color with a uniform color distribution. Figure 2 a represents undyed flame-retardant polyester fiber and Figure 2 Image b shows a scanning electron microscope (SEM) image of flame-retardant polyester fibers after dyeing in a non-aqueous medium. The undyed flame-retardant polyester fibers have a rougher surface with irregular patches, possibly caused during the flame-retardant finishing process. The dyed flame-retardant polyester fibers have a smoother surface with fewer patches, possibly because the dye penetrates the fiber interior during dyeing, and the isohexadecane depolymerizes the surface polymers under high temperature, resulting in a more uniform fiber surface. In summary, the isohexadecane dyeing system has some influence on the surface morphology of flame-retardant polyester fibers, but it does not affect the fibers themselves.

[0066] Comparative Example 3:

[0067] This experiment, referring to Example 1, discusses the effect of different auxiliaries on the dyeing effect in step (1) of the dye bath. Except for the amount of auxiliaries (auxiliary to fiber ratio of 1g:0.5ml) of 250μL, the amount of isohexadecane of 25ml, and the amount of dye of 0.01g, the other dyeing methods and process conditions are the same as in Example 1. The test results of this comparative example are shown in Table 2.

[0068] Table 2. Effects of different auxiliaries on the dyeing of flame-retardant polyester fibers in isohexadecane.

[0069]

[0070] In isohexadecane media, different auxiliaries significantly affect the dyeing effect of flame-retardant polyester fibers. Water, as the auxiliary agent, exhibits the highest K / S value, indicating the greatest dyeing depth, but poor leveling properties. DMF and ethyl acetate also show good dyeing depth, but their leveling properties are still inferior to ethanol. While ethanol and isopropanol show good leveling properties (especially ethanol, which has the best leveling properties), their K / S values ​​are low, resulting in lighter dyeing. Using only isoalkanes as the medium yields the worst dyeing effect and the lowest K / S value. Overall, highly polar auxiliaries (such as water and DMF) are more conducive to improving dyeing depth; however, DMF is a toxic substance, so this invention selects water and ethanol as auxiliaries.

[0071] Comparative Example 4:

[0072] This experiment, referring to Example 1, discusses the effect of the volume ratio of water and ethanol in the dye solution in step (1) on the dyeing effect. Except for the amount of auxiliary agent (the ratio of auxiliary agent to fiber is 1g:0.5ml), 250μL, the amount of isohexadecane, 25ml, and the amount of dye, the other dyeing methods and process conditions are the same as in Example 1. The test results of this comparative example are shown in Table 3.

[0073] Table 3. Effect of water-ethanol blend ratio on the dyeing effect of isohexadecane on flame-retardant polyester fibers.

[0074]

[0075] Table 3 (continued) Effect of water-ethanol blend ratio on the dyeing effect of isohexadecane on flame-retardant polyester fibers

[0076]

[0077] The water-ethanol blending ratio significantly affects the dyeing effect of flame-retardant polyester fibers in isoalkane media. With increasing water content, the dyeing depth (average K / S ratio) generally increases, reaching its highest value and deepest dyeing at a water-ethanol blending ratio of 10:0; conversely, lower water content results in the lowest K / S value and lighter dyeing. An 8:2 water-ethanol blending ratio provides the best leveling properties because trace amounts of water, under temperature, cause fiber swelling, allowing ethanol to carry dissolved disperse dyes into the amorphous regions of the fiber, completing the dyeing process. This invention determines that an 8:2 water-ethanol blending ratio achieves a high K / S value while maintaining excellent leveling properties.

[0078] Comparative Example 5:

[0079] This experiment, referring to Example 1, discusses the effect of the amount of auxiliary agent in the dye solution in step (1) on the dyeing effect. Except for the amount of isohexadecane (25 ml) and the amount of dye (0.01 g), the other dyeing methods and process conditions are the same as in Example 1. The test results of this comparative example are shown in Table 4.

[0080] Table 4. Effect of Auxiliary Agent Dosage on Dyeing Flame-Retardant Polyester Fibers in Isohexadecane

[0081]

[0082] The amount of auxiliaries significantly affects the dyeing effect of flame-retardant polyester fibers in isoalkanes. Table 4 shows the range of auxiliary dosage from 0 to 1 ml, based on 0.5 g of fiber. As the auxiliary dosage increases from 0 to 1 ml, the dyeing depth (average K / S ratio) shows a continuous upward trend, indicating that increasing the auxiliary concentration effectively promotes dye uptake and enhances dyeing depth. However, the levelness deteriorates significantly at auxiliary dosages of 0.75 ml and 1 ml, suggesting that excessive auxiliary dosage may cause excessive dye dissolution, leading to uneven dyeing. The optimal balance point occurs around an auxiliary dosage of 0.50 ml, where the K / S value is high and the levelness is relatively good. In summary, an appropriate amount of auxiliary can optimize dyeing depth and uniformity, while excessive use of auxiliary, although further increasing color depth, will increase unevenness. Therefore, this invention selects an auxiliary dosage of 0.50 ml, i.e., an auxiliary-to-fiber ratio of 1 g:1 ml.

[0083] Comparative Example 6:

[0084] This experiment, referring to Example 1, discusses the effect of dye dosage on the dyeing effect in step (1) of the dyeing solution. Except for the dosage of isohexadecane being 25 ml, the other dyeing methods and process conditions are the same as in Example 1. The test results of this comparative example are shown in Table 5.

[0085] Table 5. Effect of dye dosage on the dyeing effect of isohexadecane on flame-retardant polyester fibers.

[0086]

[0087] The amount of dye used has a decisive influence on the dyeing effect of flame-retardant polyester fibers in isoalkane media. As the dye concentration increases from 0.10% (owf) to 4% (owf), the dyeing depth (average K / S ratio) shows a significant upward trend, indicating a strong positive correlation between dye amount and color depth. This is because at low dye amounts, dye molecules easily diffuse into the fiber interior, achieving through-dyeing; however, as the dye amount increases, the dye aggregates, leading to uneven distribution and decreased levelness. When the concentration continues to increase to 3%-4% (owf), levelness improves somewhat but remains inferior to the low concentration state. Based on a comprehensive evaluation of coloring effect and levelness performance, this invention determines 3% (owf) as the optimal dye amount, which can achieve a high K / S value while maintaining good levelness.

[0088] Comparative Example 7:

[0089] This experiment, referring to Example 1, discusses the effect of the amount of isohexadecane in the dye solution in step (1) on the dyeing effect. Other dyeing methods and process conditions are the same as in Example 1. The test results of this comparative example are shown in Table 6 (the liquor ratio is in parentheses).

[0090] Table 6. Effect of medium dosage on the dyeing effect of flame-retardant polyester fibers in isohexadecane.

[0091]

[0092] The amount of medium used (liquor ratio) significantly affects the dyeing effect of flame-retardant polyester fibers in isohexadecane. As the liquor ratio increases from 1:10 to 1:60 (i.e., the relative amount of medium increases), the dyeing depth (average K / S ratio) shows a significant decreasing trend, indicating that reducing the amount of medium used (i.e., reducing the liquor ratio) can significantly improve the dyeing depth and color intensity. Regarding leveling properties, a liquor ratio of 1:50 yields the best leveling performance, while ratios that are too small (1:10) or too large (1:60) result in slightly poorer leveling. Considering both color depth and leveling properties, the optimal amount of isohexadecane used is 15 ml.

[0093] Comparative Example 8:

[0094] This experiment, referring to Example 1, discusses the effect of dyeing temperature on the dyeing effect in step (1) of the dye solution. Other dyeing methods and process conditions are the same as in Example 1. The test results of this comparative example are shown in Table 7.

[0095] Table 7. Effect of dyeing temperature on the dyeing of flame-retardant polyester fibers in isohexadecane.

[0096]

[0097] Dyeing temperature significantly affects the dyeing effect of flame-retardant polyester fibers in isoalkane media. At low temperatures, the dye molecules lack sufficient kinetic energy, restricting the movement of fiber macromolecular chains and resulting in low swelling and high dye diffusion resistance, thus leading to low color depth. As the temperature increases, the dye molecules' kinetic energy increases, the fiber's glass transition temperature (Tg) is exceeded, chain segment movement intensifies, the fiber swells rapidly, and micropores expand, significantly promoting dye diffusion and adsorption, resulting in a sharp increase in color depth. However, rapid dyeing leads to dye accumulation or uneven distribution on the surface, resulting in poor level dyeing. When the temperature is too high, although the fiber swells sufficiently, the dye desorption rate may accelerate, causing some dye to undergo thermal degradation or aggregation, leading to a decrease in color depth. Therefore, considering both color depth and level dyeing, this invention selects a dyeing temperature of 130℃.

[0098] Comparative Example 9:

[0099] This experiment, referring to Example 1, discusses the effect of different dyeing times on the dyeing effect in step (1) of the dye solution. Other dyeing methods and process conditions are the same as in Example 1. The test results of this comparative example are shown in Table 8.

[0100] Table 8. Effect of dyeing time on the dyeing of flame-retardant polyester fibers in isohexadecane.

[0101]

[0102] Dyeing time has a significant impact on the dyeing effect of flame-retardant polyester fibers in isoalkane media. As the time increases from 20 min to 120 min, the dyeing depth (average K / S value) first increases and then fluctuates, reaching its highest value at 60 min, indicating the most complete dye uptake during this period. With prolonged dyeing time, the apparent color yield (K / S value) of the fiber gradually increases, and the evenness of dyeing also improves accordingly. When the dyeing time is too short, the dye molecules fail to fully adsorb onto the fiber surface and diffuse inwards, resulting in insufficient dye migration and poor evenness. Appropriately extending the dyeing time helps promote the uniform distribution of dye on the fiber surface and its migration inwards, thereby simultaneously improving both color depth and dyeing uniformity. Considering all factors, the optimal dyeing time for this invention is 60 min.

[0103] Comparative examples 3-9 showed that, compared to dyeing in isohexadecane medium, adding trace amounts of water and ethanol as a compound auxiliary to the dyeing system could improve the dyeing performance of disperse dyes on flame-retardant polyester fibers in isohexadecane, while also exhibiting excellent leveling properties. Dyeing temperature, dyeing time, dye dosage, and auxiliary agent dosage all had significant effects on the dyeing effect of flame-retardant polyester fibers.

Claims

1. A non-aqueous dyeing method for flame-retardant polyester fibers with synergistic water-ethanol effect, characterized in that, The method includes the following steps: S1. Dyeing: Water and ethanol are mixed to form an auxiliary agent, which is then placed in a non-aqueous dyeing system containing disperse dyes and isohexadecane to form a dye solution; flame-retardant polyester fibers are then immersed in the dye solution for dyeing. The amount of disperse dye used is 0.1%-8% owf. Based on 1g fiber mass, the amount of isohexadecane used is 10-60 mL, the amount of auxiliary agent used is 0.25-2 mL, and the volume ratio of water to ethanol is 1:9 to 9:

1. S2. Soaping: After completing the dyeing step, the dyed fibers are placed in a soaping solution for soaping to remove excess dye.

2. The staining method according to claim 1, characterized in that: The dyeing step in S1 is performed at a temperature of 80~150 ℃ for 10~240 min; the soaping step in S2 is performed at a temperature of 60 ℃~90 ℃ for 15~60 min.

3. The staining method according to claim 1, characterized in that: The staining step described in S1 is performed at a temperature of 110~130℃ for 60~80 min.

4. The staining method according to claim 1, characterized in that: The amount of disperse dye used is 2%-4% owf.

5. The staining method according to claim 1, characterized in that: The volume ratio of water to ethanol is 7:3 to 9:

1.

6. The staining method according to claim 1, characterized in that: The volume ratio of water to ethanol is 8:

2.

7. The staining method according to claim 1, characterized in that: The disperse dye is one or more of the following: Disperse Blue UN-SE 200%, Disperse Red UN-SE 200%, and Disperse Yellow UN-SE 200%.

8. The staining method according to claim 1, characterized in that: The bath ratio of flame-retardant polyester fiber to isohexadecane is 1:3 to 1:

60.

9. The staining method according to claim 1, characterized in that: Based on 1g fiber mass, the amount of isohexadecane used is 20-40 mL, and the amount of auxiliary agent used is 0.5-1 mL.

10. A flame-retardant polyester fiber, characterized in that, It is obtained by staining using the method described in any one of claims 1 to 9.

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