Reactive dye salt-free short-process dyeing method

Abstract

The invention relates to the technical field of reactive dye dyeing, in particular to a reactive dye salt-free short-process dyeing method which comprises the following steps: S1, performing one-bath melting on a reactive dye, a migration inhibitor and a color fixing agent to obtain a mixed working solution; s2, padding a fabric in the mixed working solution to obtain a padded fabric; s3, sequentially performing drying, steaming, primary water washing, soaping, secondary water washing and ironing drying on the padded fabric. The mixed working solution is prepared from the following components in mass concentration: 1 to 50g / L of reactive dye, 10 to 15g / L of migration inhibitor and 1 to 20g / L of color fixing agent. By adopting the dyeing method, the fabric is good in dyeing depth, uniformity and dyeing fastness, meanwhile, the dyeing method has the advantages of low pollution, low energy consumption, low cost, high efficiency and the like, the industrial production requirement is met, and the dyeing method is suitable for popularization and application in the green printing and dyeing industry.

Description

Technical Field

[0001] This invention relates to the field of reactive dye dyeing technology, and specifically to a short-process reactive dye dyeing method without salt. Background Technology

[0002] Reactive dyeing technology is a widely used dyeing technique for cellulosic fibers such as cotton, linen, viscose, modal, and Tencel. Its core lies in the covalent bonding between dye molecules and fibers, thereby achieving high color fastness and vibrancy. Reactive dyes have become the primary dyes for dyeing and printing cellulosic fiber fabrics due to their characteristics such as bright colors, a complete color spectrum, low raw material costs, good leveling properties, wide applicability, and excellent wash fastness of dyed fabrics.

[0003] Currently, the conventional processes for reactive dyeing of cellulose fiber fabrics include two main processes: intermittent immersion dyeing and continuous pad-drying and steaming dyeing. These processes typically require the addition of large amounts of salt and alkali for dyeing and color fixation, resulting in problems such as low dye fixation rate, long dyeing process, high energy and water consumption, and unstable fabric quality. In particular, the treatment of high-salt wastewater is difficult, which has become a key factor restricting the green development of the printing and dyeing industry. Therefore, there is an urgent need to develop a new reactive dyeing process.

[0004] To address the technical challenges of reactive dyeing, such as the high consumption of inorganic salts and alkalis, long dyeing processes, and poor fabric dyeing quality, researchers both domestically and internationally have recently pursued salt-free or low-salt reactive dyeing through process optimization and the application of novel fixing agents. However, existing improved technologies still have significant shortcomings. While some processes reduce salt usage, the dyeing depth remains insufficient; some novel fixing agents suffer from difficulties in compounding and poor leveling properties, making it difficult to meet the demands of large-scale industrial production.

[0005] Chinese patent document with application number 201811644200.5 discloses a wet steaming salt-free dyeing process for cellulose fiber fabrics. The patent introduces a method for dyeing reactive dyes using a proportional pump, which is carried out according to the following steps: (1) padding the dye and fixing agent mixture; (2) steam fixing; (3) washing. However, this method is a wet steaming salt-free process, which has the problem of low dyeing depth.

[0006] Chinese patent document with application number 201711116090.0 discloses a method for dyeing fabrics using polymer materials. The most significant feature of this method is the use of a special fixing agent in the dyeing process. The special fixing agent includes the following raw materials in parts by weight: 700-800 parts of sodium metasilicate pentahydrate, 200-300 parts of urea, and 1-5 parts of sodium dodecylbenzene sulfonate. However, the problem is that the fixing agent is a polymer material, which is difficult to dissolve, has poor affinity with water, and easily produces "stripes" and "color stains" on the fabric surface after dyeing. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a salt-free, short-process dyeing method for reactive dyes. A small-molecule fixing agent is used, which is mixed with the reactive dye in a bath before padding the fabric. This combined "pad-dry-steam" short-process dyeing achieves salt-free, high-efficiency dyeing. The reactive dye and fixing agent are mixed in a bath, and the fabric is then dyed using the same bath. Steaming allows the reactive dye to form strong electrophilic centers, while simultaneously causing the cellulose fibers to form nucleophilic cellulose oxygen anions. This enhances the formation of covalent bonds between the reactive dye and the cellulose oxygen anions, avoiding the need for large amounts of caustic soda, soda ash, and salts to achieve color fixation during the reactive dye steaming process. It also reduces pollution during the washing process, lessens the burden on wastewater treatment, and is energy-saving and environmentally friendly. This method is suitable for dyeing light, medium, and dark colors of cellulose fiber fabrics.

[0008] The technical solution of this invention is as follows: This invention provides a salt-free, short-process dyeing method for reactive dyes, comprising the following steps: S1. Mix the reactive dye, anti-migration agent and fixing agent in the same bath to obtain a mixed working solution; S2. Impregnate the fabric with the mixed working solution to obtain the impregnated fabric; S3. The impregnated fabric is then dried, steamed, washed once, soaped, washed twice, and ironed.

[0009] Furthermore, in step S1, the mixed working solution comprises the following components at mass concentrations: 1-50 g / L of reactive dye, 10-15 g / L of anti-migration agent, and 1-20 g / L of fixing agent. The purpose of adding the anti-migration agent is to effectively prevent dye particles from migrating with the moisture flow during the drying process, avoid dye aggregation or uneven distribution on the fabric surface, and ensure the overall uniformity of the dyed fabric appearance.

[0010] Furthermore, in step S1, the fixing agent is a compound of sodium hydroxide and sodium silicate in a mass ratio of 1:3 to 1:5. When this fixing agent is applied to the fabric in the same bath as the reactive dye, steaming enables the reactive dye to form strong electrophilic centers, while simultaneously causing the cellulose fibers to form nucleophilic cellulose oxygen anions. This enhances the formation of covalent bonds between the reactive dye and the cellulose oxygen anions, avoiding the need for large amounts of caustic soda, soda ash, and salts to achieve the color-fixing effect during the steaming process of the reactive dye.

[0011] Furthermore, in step S2, the padding residue rate during impregnation is 50%-65%. This ensures that the fabric absorbs a sufficient amount of the mixed working solution to guarantee the amount of color obtained, while avoiding excessive liquid carryover that could lead to dye migration during drying.

[0012] Furthermore, in step S3, the drying temperature is 60-80℃. The medium-low temperature drying mode can slowly evaporate the moisture from the fabric, preventing dye molecules from rapidly agglomerating and clumping at high temperatures, ensuring uniform dye dispersion; at the same time, it reduces excessive shrinkage of cellulose fibers caused by high temperatures, maintaining the original soft feel of the fabric and avoiding problems such as stiffness and wrinkling.

[0013] Furthermore, in step S3, the steaming temperature is 98-102℃, and the steaming time is 50-120s. This temperature range can efficiently activate the activity of the fixing agent, promote the formation of stable covalent bonds between the dye and the fiber, and improve the fixing rate; the 50-120s time setting can be adapted to different dye concentrations and fabric thicknesses, ensuring sufficient reaction without wasting energy, and avoiding incomplete fixing due to too short a time or dye hydrolysis due to too long a time.

[0014] Furthermore, in step S3, the first wash is a room temperature wash for 1-2 minutes. The purpose of the first wash is to remove unreacted free dyes and excess fixing agents from the fabric surface.

[0015] Furthermore, in step S3, the soaping is performed using 95°C hot water with added soaping agent at a dosage of 1-3 g / L for 1-2 minutes. High temperature enhances the penetration and cleaning power of the soaping agent, effectively removing firmly adsorbed loose dye from the fabric surface.

[0016] Furthermore, in step S3, the secondary wash is performed with room temperature water for 1-2 minutes. This removes residual soaping agent and loose dye from the fabric surface, preventing residual auxiliaries from affecting the fabric's feel or subsequent finishing processes.

[0017] Furthermore, in step S3, the fabric that has undergone a second washing process is ironed dry to obtain a dried dyed fabric product.

[0018] The beneficial effects of this invention are as follows: (1) This invention uses a small molecule fixing agent and reactive dye in the same bath to dye the fabric. Steaming enables the reactive dye to form a strong electrophilic center, while the cellulose fiber forms a nucleophilic cellulose oxygen anion, which improves the formation of covalent bonds between the reactive dye and the cellulose oxygen anion. This avoids the need for large amounts of caustic soda, soda ash, and salt to achieve the color-fixing effect in the steaming process of reactive dyes. Experimental data show that a fixing agent concentration of 3-5 g / L can achieve a deep and uniform dyeing effect (Reactive Red SBE color strength exceeds 100), while traditional baking soda requires 10-20 g / L to achieve a similar effect, resulting in higher dyeing efficiency.

[0019] (2) Fabrics dyed using the technical solution of this invention achieve the same dyeing effect and fastness as traditional "pad-dry-pad-steam" processes. Furthermore, by controlling parameters such as a 50-65% pick-up rate, 60-80℃ drying, and 98-102℃ steaming, dye migration and aggregation are effectively avoided, resulting in uniform color, rich hue, and no "stripes" or other defects. Testing shows that the fastness indicators for soaping, rubbing, and perspiration all meet the standards of traditional "pad-dry-pad-steam" processes, satisfying industry standards.

[0020] (3) This process optimizes the traditional process into a salt-free short process of "rolling-drying-steaming", eliminating the secondary alkali rolling step, shortening the production cycle, and saving 100% of the salt usage. The process simplification significantly reduces the heat and water consumption of the drying and rolling stages, and the dyeing depth and uniformity of the fabric are better, which not only reduces the production cost, but also reduces the burden of wastewater treatment, and meets the industrial production needs of cellulose fiber fabrics. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0022] The device used in this embodiment of the invention is: Thermal circulation oven (OVEN R-1 type, Xiamen Ruibi Precision Machinery Co., Ltd.); Air-compressed film type horizontal strength padding and dyeing tester (Xiamen Ruibi Precision Machinery Co., Ltd.); Sample steaming machine (STM-G600 type, Suzhou Industrial Park Yamei Textile Machinery & Electrical Co., Ltd.).

[0023] In this embodiment of the invention, cellulose fiber fabric is used as the fabric to be dyed. In the embodiments of the invention, the cellulose fiber fabric is a general woven fabric, and there are no special restrictions on its structure (such as plain weave, twill weave), specifications (such as weight, yarn count), etc.

[0024] The mixed working solution described in this embodiment of the invention comprises: 1-50 g / L of reactive dye, 10-15 g / L of anti-migration agent, and 1-20 g / L of fixing agent. This embodiment of the invention uses conventional water in the art, and the dye solution can be prepared and mixed evenly at room temperature.

[0025] In this embodiment of the invention, the roll-off rate is used to characterize the amount of liquid carried by the fabric after rolling. The calculation formula is: Roll-off rate = (weight of fabric after rolling - weight of fabric before rolling) / weight of fabric before rolling × 100%.

[0026] The color fastness and color depth of the examples and comparative examples were tested. The specific experimental methods are as follows: Test items: K / S value of dyed fabrics, color strength, washing fastness, rubbing fastness, perspiration fastness, ironing fastness, light fastness, chlorine washing fastness, and perspiration-light composite fastness.

[0027] K / S value: Tested using the Datacolor colorimetric system. The fabric is folded into four layers and placed on the colorimetric system's testing platform. The colorimetric program is then started. The computer colorimetric system uses the reflectance at different wavelengths and the CIELAB formula to calculate the differences in brightness (CIE DL), red / green (CIE Da), yellow / blue (CIE Db), saturation (CIE DC), hue (CIE DH), and overall color difference (CIE DE) between the standard and test samples. The data can be directly read from the Datacolor colorimetric data source.

[0028] Fastness to washing with soap is tested according to AATCC 612A; fastness to rubbing is tested according to AATCC 8; fastness to perspiration is tested according to GB-T 3922; fastness to ironing is tested according to GB-T 6152; fastness to sunlight is tested according to AATCC 16; fastness to chlorine washing is tested according to AATCC 61-4A; and fastness to a combination of perspiration and light is tested according to AATCC 125.

[0029] To further understand this application, the following describes in detail, with reference to embodiments, a salt-free short-process dyeing method for reactive dyes provided in this application.

[0030] (I) Comparison of fabric dyeing effects with different fixing agents and different fixing agent concentration gradients Example 1 Experimental fabric: C20x16100x58 plain weave The staining method includes the following steps: S1. Mix 20 g / L Reactive Red SBE (Wuxi Runxin Dyestuff Co., Ltd.), 10 g / L Anti-migration Agent TX (Shanghai Kekai Chemical Co., Ltd.), and 2 g / L Fixing Agent (Sodium hydroxide: Sodium silicate = 1:3 mass ratio) in the same dye bath to obtain a mixed working solution; S2. The fabric is impregnated with the mixed working solution using an air-compressed film horizontal strength padding and dyeing tester with a padding rate of 50% to obtain the impregnated fabric. S3. After impregnation, the fabric is dried at 60℃, steamed at 100℃ for 70s, washed with room temperature water for 2min, soaped in 95℃ hot water for 1min with soaping agent dosage of 2g / L, washed with room temperature water for 2min, and ironed dry.

[0031] The difference between Examples 2-7 and Example 1 is that the amount of fixing agent used is 3g / L, 4g / L, 5g / L, 10g / L, 15g / L, and 20g / L, respectively.

[0032] Comparative Example 1 Experimental fabric: C20x16100x58 plain weave The staining method includes the following steps: S1. Thoroughly mix 20 g / L Reactive Red SBE (Wuxi Runxin Dyestuff Co., Ltd.), 10 g / L Anti-migration Agent TX (Shanghai Kekai Chemical Co., Ltd.), and 2 g / L Sodium Bicarbonate (Shandong Haihua Co., Ltd.) to obtain a mixed working solution. S2. The fabric is impregnated with the mixed working solution using an air-compressed film horizontal strength padding and dyeing tester with a padding rate of 50% to obtain the impregnated fabric. S3. After impregnation, the fabric is dried at 60℃, steamed at 100℃ for 70s, washed with room temperature water for 2min, soaped in 95℃ hot water for 1min with soaping agent dosage of 2g / L, washed with room temperature water for 2min, and ironed dry.

[0033] The difference between Comparative Examples 2-7 and Comparative Example 1 is that the amount of baking soda used was 3g / L, 4g / L, 5g / L, 10g / L, 15g / L, and 20g / L, respectively.

[0034] Color measurement data of the fabric after dyeing using the above process: Table 1. Comparison of fabric dyeing effects with different concentrations of Reactive Red SBE fixing agent (using 5 g / L fixing agent as a standard sample for comparison).

[0035] Table 2 Comparison of fabric dyeing effects of Reactive Red SBE with different sodium bicarbonate concentrations (with 5 g / L sodium bicarbonate as the standard sample).

[0036] Analysis of the data in Tables 1 and 2 shows that at a concentration of 20 g / L for the reactive dye SBE Red, a fixing agent concentration of 3-5 g / L is sufficient to achieve a good dyeing effect. After dyeing with 10-20 g / L of baking soda, the fabric surface can achieve a relatively deep and uniform color. The amount of fixing agent required is smaller, resulting in excellent economic efficiency.

[0037] Example 8 Experimental fabric: C20x16100x58 plain weave The staining method includes the following steps: S1. Mix 20 g / L Reactive Blue EC-R (Huntsmay Group), 10 g / L Anti-migration Agent TX (Shanghai Kekai Chemical Co., Ltd.) and 1 g / L Fixing Agent in the same dye bath (sodium hydroxide: sodium silicate = 1:5 mass ratio) to obtain a mixed working solution; S2. The fabric is impregnated with the mixed working solution using an air-compressed film horizontal strength padding and dyeing tester with a padding rate of 50% to obtain the impregnated fabric. S3. After impregnation, the fabric is dried at 60℃, steamed at 100℃ for 70s, washed with room temperature water for 2min, soaped in 95℃ hot water for 1min with soaping agent dosage of 2g / L, washed with room temperature water for 2min, and ironed dry.

[0038] The difference between Examples 9-15 and Example 8 is that the amount of fixing agent used is 2g / L, 3g / L, 4g / L, 5g / L, 10g / L, 15g / L, and 20g / L, respectively.

[0039] Comparative Example 8 Experimental fabric: C20x16100x58 plain weave The staining method includes the following steps: S1. Thoroughly mix 20 g / L Reactive Blue EC-R (Huntsman Group), 10 g / L Anti-migration Agent TX (Shanghai Kekai Chemical Co., Ltd.), and 1 g / L Sodium Bicarbonate (Shandong Haihua Co., Ltd.) to obtain a mixed working solution; S2. The fabric is impregnated with the mixed working solution using an air-compressed film horizontal strength padding and dyeing tester with a padding rate of 50% to obtain the impregnated fabric. S3. After impregnation, the fabric is dried at 60℃, steamed at 100℃ for 70s, washed with room temperature water for 2min, soaped in 95℃ hot water for 1min with soaping agent dosage of 2g / L, washed with room temperature water for 2min, and ironed dry.

[0040] The difference between Comparative Examples 9-15 and Comparative Example 8 is that the amount of baking soda used was 2g / L, 3g / L, 4g / L, 5g / L, 10g / L, 15g / L, and 20g / L, respectively.

[0041] Color measurement data of the fabric after dyeing using the above process: Table 3. Comparison of fabric dyeing effects with different fixing agent concentrations of Reactive Blue EC-R (using 5 g / L fixing agent as a standard sample for comparison).

[0042] Table 4. Comparison of fabric dyeing effects of Reactive Blue EC-R with different sodium bicarbonate concentrations (using 5 g / L sodium bicarbonate as a standard sample for comparison).

[0043] Analysis of the data in Tables 3 and 4 shows that when the concentration of reactive dye EC-R blue is 20 g / L, the fabric can achieve a relatively dark color after dyeing with a fixing agent of 3-5 g / L and baking soda of 3-10 g / L. However, the comparison of K / S values ​​shows that the fabric dyed with the fixing agent is darker.

[0044] (II) Comparison of the effects of salt-free short-process dyeing and long-process pad-drying-steam dyeing Example 16 Salt-free short-process dyeing process Experimental fabric: C20x16100x58 plain weave The staining method includes the following steps: S1. Mix 20 g / L Reactive Blue EC-R (Huntsman Group), 10 g / L Anti-migration Agent TX (Shanghai Kekai Chemical Co., Ltd.) and 5 g / L Fixing Agent (Sodium hydroxide: Sodium silicate = 1:3 mass ratio) in the same dye bath to obtain a mixed working solution; S2. The fabric is impregnated with the mixed working solution using an air-compressed film horizontal strength padding and dyeing tester with a padding rate of 50% to obtain the impregnated fabric. S3. After impregnation, the fabric is dried at 60℃, steamed at 100℃ for 70s, washed with room temperature water for 2min, soaped in 95℃ hot water for 1min with soaping agent dosage of 2g / L, washed with room temperature water for 2min, and ironed dry.

[0045] Comparative Example 16: Long-carriage "roll-dry-roll-steam" dyeing process Active Blue EC-R (Huntsman Group) 20g / L Anti-migratory agent TX (Shanghai Kekai Chemical Co., Ltd.) 10g / L Process flow: Weighing dye → Padding dye → Pre-drying at 80℃ → Padding and steaming fixing solution (salt 200g / L; soda ash 20g / L; caustic soda 6g / L) → Steaming (100℃×70s) → Water washing → Hot water washing → Soap washing → Water washing → Drying.

[0046] Color measurement data of the fabric after dyeing using the above process: Table 5. Dyeing effects of fabrics dyed using different processes

[0047] Table 6. Surface fastness of fabrics dyed using different processes

[0048] Analysis of the data in Tables 5 and 6 shows that the K / S value of Example 16 is 13.8530 and the color strength is 107.28%, which is better than the rolling-steaming and rolling-drying process of Comparative Example 16. In addition, the fastness index of the short process is basically the same as that of the rolling-drying and rolling-steaming process, which meets the industry standard.

[0049] (III) Comparison of dyeing effects of different fixing agents Example 17 S1. Mix 20 g / L Reactive Blue EC-R (Huntsman Group), 10 g / L Anti-migration Agent TX (Shanghai Kekai Chemical Co., Ltd.) and 5 g / L Fixing Agent (Sodium hydroxide: Sodium silicate = 1:4 mass ratio) in the same dye bath to obtain a mixed working solution; S2. The fabric is impregnated with the mixed working solution using an air-compressed film horizontal strength padding and dyeing tester with a padding rate of 50% to obtain the impregnated fabric. S3. After impregnation, the fabric is dried at 60℃, steamed at 100℃ for 70s, washed with room temperature water for 2min, soaped in 95℃ hot water for 1min with soaping agent dosage of 2g / L, washed with room temperature water for 2min, and ironed dry.

[0050] Comparative Example 17 S1, 750 parts of sodium metasilicate pentahydrate, 250 parts of urea, and 2 parts of sodium dodecylbenzenesulfonate are compounded. 32g of the compound fixing agent is dissolved in 500ml of water to obtain the fixing agent solution. S2: Thoroughly mix 20g of Reactive Blue EC-R and 10g of Anti-migration Agent TX in 500ml of water to obtain a mixed dye solution; S3. Thoroughly mix the fixing agent solution prepared in step S1 with the mixed dye solution prepared in step S2 to obtain the mixed working solution. S4: The fabric is immersed in the mixed working solution using a pneumatic film type horizontal strength padding and dyeing tester with a padding rate of 50% to obtain the padded fabric. S5: Dry the impregnated fabrics sequentially at 80℃, controlling the fabric surface moisture content to 5-10%; S6: Steam the fabric dried in S5 at 100℃ for 70 seconds, wash with room temperature water for 2 minutes, soap it in 95℃ hot water for 1 minute with soaping agent dosage of 2g / L, wash it again with room temperature water for 2 minutes, and iron it dry.

[0051] Table 7. Dyeing effects of fabrics after dyeing with different fixing agents in Example 17 and Comparative Example 17

[0052] As can be seen from the data in Table 7, the difference in fabric depth after dyeing using the fixing agent formulated with inorganic and organic compounds in Comparative Example 17 is significant compared to that in Example 17 of this invention. Comparative Example 17 uses a larger amount of fixing agent and contains a certain proportion of sodium dodecylbenzenesulfonate, which puts greater pressure on wastewater treatment. Furthermore, the low dye uptake rate at the same dye concentration leads to increased dye discharge into the wastewater, resulting in dye waste and further complicating wastewater treatment.

[0053] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A short-process dyeing method for reactive dyes without salt, characterized in that, Includes the following steps: S1. Mix the reactive dye, anti-migration agent and fixing agent in the same bath to obtain a mixed working solution; S2. Impregnate the fabric with the mixed working solution to obtain the impregnated fabric; S3. The impregnated fabric is then dried, steamed, washed once, soaped, washed twice, and ironed.

2. The short-process reactive dyeing method according to claim 1, characterized in that, In step S1, the mixed working solution comprises the following components at mass concentrations: 1-50 g / L of reactive dye, 10-15 g / L of anti-migration agent, and 1-20 g / L of fixing agent.

3. The short-process reactive dyeing method without salt as described in claim 2, characterized in that, The fixing agent is a compound of sodium hydroxide and sodium silicate in a mass ratio of 1:3 to 1:

5.

4. The short-process reactive dyeing method without salt as described in claim 1, characterized in that, In step S2, the roll residue during impregnation is 50%-65%.

5. The short-process reactive dyeing method without salt as described in claim 1, characterized in that, In step S3, the drying temperature is 60-80℃.

6. The short-process reactive dyeing method according to claim 1, characterized in that, In step S3, the temperature of the steam is 98-102℃ and the steaming time is 50-120s.

7. The short-process reactive dyeing method according to claim 1, characterized in that, In step S3, the first water wash is a room temperature water wash, and the water wash time is 1-2 minutes.

8. The short-process reactive dyeing method according to claim 1, characterized in that, In step S3, the soaping is performed using 95°C hot water with added soaping agent, the amount of soaping agent being 1-3 g / L, and the soaping time being 1-2 min.

9. The short-process reactive dyeing method according to claim 1, characterized in that, In step S3, the secondary water wash is a room temperature water wash for 1-2 minutes.

10. The short-process reactive dyeing method according to claim 1, characterized in that, In step S3, the fabric that has undergone a second washing process is ironed dry to obtain a dried dyed fabric product.

Images