Reactive dye efficient ink-jet dyeing process and application

Abstract

The invention belongs to the technical field of textile printing and dyeing, relates to an efficient reactive dye ink-jet dyeing process and application, and aims to solve the problems that the traditional dyeing proofing process is tedious, the color difference of front and back surfaces of ink-jet dyeing is large, and the dye utilization rate is low. The process comprises the following steps: firstly, padding a fabric in an aqueous solution until the pick-up rate is controlled to be 60-120%, and carrying out ink-jet printing on reactive dye ink (the viscosity is 3-10 mPa.s and the surface tension is 20-50 mN / m) in a wet fiber swelling state; after printing, a 1%-10% alkali solution is immediately padded to promote permeation of the dye; and then pre-drying at 60-70 DEG C, steaming with saturated steam at 100-102 DEG C for 5-15 minutes, and washing with water to complete color fixation. According to the technology, the K / S ratio of the front face and the back face of the dyed fabric is larger than or equal to 0.95, the color fastness of the dry friction level 4-5 or above, the color fastness of the wet friction level 4-5 and the color fastness of the soaping level 4-5 are achieved, and the technology is suitable for green efficient dyeing of small-batch multi-variety fabric.

Description

Technical Field

[0001] This invention relates to the field of textile printing and dyeing technology, specifically to a high-efficiency inkjet dyeing process and application of reactive dyes, which achieves intelligent dyeing with high dye utilization and low pollution by optimizing the ink penetration and color fixing process. Background Technology

[0002] According to the China Printing and Dyeing Industry Association, dyed fabrics account for more than 75% of the total volume of printed and dyed fabrics (dyed / printed / bleached). However, traditional reactive dye padding / immersion dyeing remains the mainstream method for dyeing cotton fabrics, but its high liquor ratio, high salt consumption, low dye utilization rate, and large amount of wastewater discharge have long constrained the industry's green development. To overcome these shortcomings, domestic and foreign manufacturers mostly adopt cationic modification, short-process wet steaming, or salt-free dyeing processes, such as the continuous cationic modification-reactive dye padding and steaming method disclosed by Shanghai University (ZL201811321904.9). This method improves the fixation rate and reduces salt consumption through microwave pretreatment, but still requires two padding processes, making it difficult to achieve digital, small-batch, flexible production.

[0003] Digital inkjet printing technology, due to its elimination of the need for plate making and on-demand ink dispensing, has become an important embodiment of technology, green practices, and fashion in the textile industry. Existing inkjet printing (such as CN202510392541.1: A high dye utilization ink for inkjet printing and its preparation method, CN101113567A: Low-temperature plasma treatment process for fabrics used in digital inkjet printing of pigment inks, etc.) is a non-contact surface deposition method, where the ink only accumulates on the surface of the fabric, resulting in large color differences between the front and back sides and insufficient penetration, making it difficult to meet the strict requirement of "same color on both sides" for dyed fabrics.

[0004] In recent years, the concept of wet inkjet printing has begun to attract attention: utilizing pre-wetted and swollen fibers before inkjet deposition can significantly improve dye penetration and utilization. However, existing technologies (such as the spray-based wet steaming device in CN201811321924.6) still rely on continuous pad-steaming, failing to integrate digital inkjet printing with instant alkali pad-steaming for enhanced penetration and low liquid carryover rate steaming into a unified process. Furthermore, they have not systematically optimized the diffusion-fixation mechanism of reactive dyes in a wet fabric matrix. Therefore, developing a wet inkjet dyeing method that combines digitalization, high penetration, high fixation rate, and applicability to various fabrics remains a crucial technological gap that the industry urgently needs to overcome. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a high-efficiency inkjet dyeing process and application for reactive dyes. Through a continuous process of "pre-wetting treatment - post-inkjet dyeing - alkali-intensified padding - steam fixation", dye molecules can fully penetrate the fabric in the thickness direction, significantly improving dye utilization and achieving high color consistency on both sides.

[0006] To solve the above technical problems, the present invention adopts the following technical solution: One objective of this invention is to provide a high-efficiency inkjet dyeing process for reactive dyes. The dyeing process includes wet printing of the fabric, padding with alkaline solution for penetration, and steam fixing treatment, comprising the following steps: S1, Wet printing of fabric First, the fiber fabric is wetted and swollen by padding with an aqueous solution. Then, an inkjet printer is used to spray reactive dye ink onto the surface of the wet fabric as needed, resulting in a wet-printed fabric.

[0007] Preferably, the fiber fabric includes, but is not limited to, natural cellulose fiber fabrics such as cotton and linen, natural protein fiber fabrics such as wool and silk, and renewable cellulose fiber fabrics such as lyocell and viscose.

[0008] Preferably, the immersion in the aqueous solution is carried out by one dip and one roll or two dips and two rolls, with the roll residue controlled at 60-120%.

[0009] Furthermore, the aqueous solution contains a penetrant, which is one or more of sodium dodecyl sulfate, naphthalene sulfonate anionic penetrants, polyethylene glycol (molecular weight 200-600), and polyoxyethylene octylphenyl ether nonionic penetrants, and the amount added is 0-3 g / L.

[0010] Preferably, the reactive dye ink has a viscosity of 3–10 mPa·s, a surface tension of 20–50 mN / m, four colors (C / M / Y / K), and an injection rate controlled at 5–30 g / m. 2 The nozzle resolution is ≥600 dpi.

[0011] S2, alkali impregnation solution The wet printing fabric is immersed in alkaline solution and then dried. The immersion and padding method is one dip and one pad, and the padding rate is controlled at 65-120%. The wet printing fabric is then treated with alkali.

[0012] Preferably, the type of alkaline solution includes, but is not limited to, sodium hydroxide solution, sodium bicarbonate solution, and sodium carbonate solution, and the mass fraction of the alkaline solution is 1-10%.

[0013] Preferably, the drying temperature is 60-70°C and the drying time is 8-12 hours.

[0014] S3, Steam color fixing The wet-printed fabric treated with alkali is then subjected to a steam fixation process, followed by water washing to complete the fixation.

[0015] Preferably, the steam color-fixing process uses saturated steam at 100-102°C, the steaming time is 5-15 minutes, and the humidity is 90-98%.

[0016] The second objective of this invention is to provide an application of a high-efficiency inkjet dyeing process for reactive dyes. The application involves using the above process to inkjet dye different types of fabrics, with the dyed fabric having a K / S ratio ≥0.95 on both sides, and color fastness of 4-5 or higher for dry rubbing, wet rubbing, and soaping.

[0017] As is well known, dyeing and printing factories currently struggle to achieve digital, small-batch, flexible production during the sampling stage before reactive dyeing. Traditional reactive dye padding / immersion dyeing remains the mainstream method for fabric dyeing, but it suffers from drawbacks such as high liquor ratio, high salt consumption, low dye utilization, and large amounts of wastewater discharge. This invention abandons the traditional padding / immersion dyeing technique for fabrics, instead using inkjet dyeing to directly print ink onto the wet-treated fabric, followed by a second padding with alkaline solution and steam fixing. The difference from traditional inkjet printing technology lies in the fact that, to maintain printing accuracy, traditional inkjet printing only accumulates ink on the fabric surface, resulting in significant color differences between the front and back sides and insufficient penetration. This technology combines the advantages of inkjet printing—customizable colors and rapid printing—to improve dye utilization and solve the problems of high energy consumption, significant color differences between the front and back sides, and large amounts of colored wastewater discharge. The specific mechanism is as follows: In its initial dry state, cellulose molecules are tightly packed together by intermolecular hydrogen bonds, forming crystalline (orderly and compact) and amorphous (loose and disordered but still dense) regions. At this stage, the intermolecular hydrogen bonds make the fiber structure dense, leaving insufficient space for dye or water molecules to penetrate, resulting in a stable state of low reactivity and low permeability. When the fiber is impregnated with an aqueous solution, water molecules (polar molecules) diffuse into the amorphous region of the fiber (which is difficult to penetrate in the crystalline region due to its density). Water molecules form new hydrogen bonds with the hydroxyl groups (-OH) of cellulose molecules, breaking some of the original intermolecular hydrogen bonds, increasing the interchain spacing and expanding the micropores in the amorphous region, causing the fiber volume to swell (swelling). This swelling in water expands the micropores in the amorphous region, providing diffusion channels for dye molecules. Reactive dyes contain sulfonic acid groups (such as -SO3Na, polar groups), which dissolve in water into ionic states and can diffuse. The dye enters the amorphous region via a concentration gradient, and the dye molecules can weakly bind to the cellulose hydroxyl groups through hydrogen bonds and van der Waals forces, promoting their adsorption in the amorphous region. However, because the crystalline region is not open, only the amorphous region contains dye, which cannot fully penetrate the fiber. When impregnated with alkaline solution, the OH⁻ reacts with the hydroxyl groups of cellulose molecules, more efficiently breaking the hydrogen bonds between cellulose molecules and significantly improving the internal space and connectivity of the fiber. Therefore, the swelling effect of alkaline solution on cotton fibers is much stronger than that of water, further promoting the complete penetration of dye molecules. After the dye molecules have fully penetrated, the alkaline conditions cause the hydroxyl groups (-OH) of cellulose molecules to ionize into more nucleophilic oxygen anions (-O-), while simultaneously activating the active groups in the dye molecules (such as monochlorotriazine). During steaming, a nucleophilic substitution reaction occurs between the reactive dye and the fiber, achieving covalent bonding, thereby giving the dyed fabric good colorfastness.

[0018] Therefore, this invention, through the concept of inkjet dyeing, not only solves the problems of long process flow, low dye utilization rate and large amount of auxiliary agent in traditional reactive dye dyeing process, but also solves the problem of large color difference between the front and back of the fabric caused by inkjet printing. Thus, while effectively ensuring the dyeing effect, it also significantly saves the amount of auxiliary agent and water, shortens the process flow, and improves the production efficiency of reactive dye dyeing.

[0019] By adopting the above technical solution, the technical effect achieved by this invention is as follows: 1. The reactive dye high-efficiency inkjet dyeing process provided by the present invention belongs to the field of textile printing and dyeing technology. It has the characteristics of short process flow, low energy consumption, dye utilization rate increased by more than 20%, and environmental friendliness, which meets the needs of digital, flexible and green manufacturing.

[0020] 3. The present invention develops a high-efficiency inkjet dyeing process for reactive dyes, which utilizes a wet-wet synergistic penetration mechanism to enable the reactive dyes to diffuse rapidly by the alkali agent while the fiber channels are still in a highly swollen state, thereby achieving the same color on both sides (K / S penetration rate ≥95%).

[0021] 4. The present invention provides a high-efficiency inkjet dyeing process for reactive dyes. As an emerging green printing and dyeing process, it integrates the excellent performance of inkjet printing and reactive dye inks, thus filling the technological gap in the dual functions of "digitalization + high penetration" in traditional pad dyeing / inkjet printing. Attached Figure Description

[0022] Figure 1 The K / S ratio and color effect of the inkjet-dyed fabric (C / M / Y / K) in Example 1 are shown. Detailed Implementation

[0023] The present invention will be further illustrated below with reference to specific embodiments.

[0024] Example 1: A high-efficiency inkjet dyeing process for reactive dyes and its application, the process comprising the following steps: S1, Wet printing of fabric First, the cotton fabric is wetted and swollen by padding with an aqueous solution. Then, an inkjet printer is used to spray reactive dye ink onto the surface of the wet fabric as needed, resulting in a wet-printed fabric.

[0025] The method of immersion in the aqueous solution is one immersion and one rolling, with the roll residue controlled at 100%.

[0026] The reactive dye ink has a viscosity of 5 mPa·s, a surface tension of 30 mN / m, and is available in four colors: C, M, Y, and K. The spraying rate is controlled at 20 g / m. 2 The nozzle resolution is 600 dpi.

[0027] S2, alkali impregnation solution The wet-state printing fabric is impregnated with alkaline solution and then dried. The impregnation method is one dip and one roll, and the roll-off rate is controlled at 100%. The wet-state printing fabric is then treated with alkali.

[0028] The alkaline solution is a sodium carbonate solution with a mass fraction of 5%.

[0029] The drying temperature is 60°C and the time is 10 hours.

[0030] S3, Steam color fixing The wet-printed fabric treated with alkali is then subjected to a steam fixation process, followed by water washing to complete the fixation.

[0031] The steam color-fixing process uses 100°C saturated steam for 10 minutes at a humidity of 95%.

[0032] The K / S ratio of the front and back sides of the cotton fabric dyed using Example 1 is ≥0.95, as shown in Table 1. At the same time, the color fastness is rated as 4-5 for dry rubbing, 4-5 for wet rubbing, and 4-5 for soap washing.

[0033] Table 1. K / S values ​​and ratios of the four colors C / M / Y / K in cotton fabric of Example 1 Example 2: The difference between this example and Example 1 is that the viscosity of the reactive dye ink is 5 mPa·s, the surface tension is 30 mN / m, and it uses three colors: CM / CY / MY. The spraying amount is controlled at 20 g / m. 2 The nozzle resolution is 600 dpi.

[0034] The K / S ratio of the front and back sides of the cotton fabric dyed using Example 2 is ≥0.95, as shown in Table 2. At the same time, the color fastness is 4-5 for dry rubbing, 4-5 for wet rubbing, and 4-5 for soap washing.

[0035] Table 2. K / S values ​​and ratios of the three color combinations CM / CY / MY in cotton fabrics in Example 2. Example 3: A high-efficiency inkjet dyeing process for reactive dyes and its application, the process comprising the following steps: S1, Wet printing of fabric First, the Lyocell fabric is wetted and swollen by padding with an aqueous solution. Then, an inkjet printer is used to spray reactive dye ink onto the surface of the wet fabric as needed, resulting in a wet-printed fabric.

[0036] The method of immersion in the aqueous solution is one immersion and one rolling, with the roll residue controlled at 120%.

[0037] The inkjet dyeing reactive dye ink has a viscosity of 10 mPa·s, a surface tension of 30 mN / m, and is available in four colors: C, M, Y, and K. The spraying rate is controlled at 15 g / m³. 2 The nozzle resolution is 600 dpi.

[0038] S2, alkali impregnation solution The wet-state printing fabric is impregnated with alkaline solution and then dried. The impregnation method is one dip and one roll, and the roll-off rate is controlled at 100%. The wet-state printing fabric is then treated with alkali.

[0039] The alkaline solution is a sodium carbonate solution with a mass fraction of 10%.

[0040] The drying temperature is 60°C and the time is 12 hours.

[0041] S3, Steam color fixing The wet-printed fabric treated with alkali is then subjected to a steam fixation process, followed by water washing to complete the fixation.

[0042] The steam color-fixing process uses 100°C saturated steam for 15 minutes at a humidity of 98%.

[0043] The K / S ratio of the front and back sides of the Lyocell fabric dyed using Example 3 is ≥0.95, as shown in Table 3. At the same time, the color fastness is rated as 5 for dry rubbing, 4-5 for wet rubbing, and 4-5 for soap washing.

[0044] Table 3. K / S values ​​and ratios of the four colors (C / M / Y / K) in Lyocell fabric in Example 3 Comparative Example 1: Example 1, a representative example, was selected as Comparative Example 1. First, cotton fabric was wetted by padding with a sodium carbonate solution (5% by mass). Then, an inkjet printer was used to spray reactive dye ink onto the wet fabric surface as needed. The reactive dye ink had a viscosity of 5 mPa·s, a surface tension of 30 mN / m, and was available in four colors: C, M, Y, and K. The spraying amount was controlled at 20 g / m³. 2 The nozzle resolution is 600 dpi. The drying temperature of the oven is 60℃. The steam fixation process for the fabric involves steaming with saturated steam at 100℃ for 10 minutes, followed by washing with water to complete the fixation. Application effect of Comparative Example 1: The K / S ratio of the front and back sides of the dyed cotton fabric is ≤0.95, as shown in Table 4. Simultaneously, the color fastness is rated at dry rubbing grade 4, wet rubbing grade 4, and soap washing grade 4.

[0045] Table 4. K / S values ​​and ratios of the four colors C / M / Y / K in cotton fabrics of Comparative Example 1 Unless otherwise specified, all proportions and percentages mentioned in this invention are mass proportions and mass percentages; all raw materials are commercially available.

[0046] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-efficiency inkjet dyeing process for reactive dyes, characterized in that, The dyeing process includes wet printing of the fabric, padding with alkaline solution, and steam fixing.

2. The high-efficiency inkjet dyeing process for reactive dyes according to claim 1, characterized in that, The wet printing of the fabric is performed by first wetting and swelling the fiber fabric by padding with an aqueous solution, and then using an inkjet printer to spray reactive dye ink onto the surface of the wet fabric as needed, thus obtaining a wet-printed fabric.

3. The high-efficiency inkjet dyeing process for reactive dyes according to claim 2, characterized in that, The fiber fabrics include, but are not limited to, cotton and linen fabrics, natural cellulose fiber fabrics, wool and silk natural protein fiber fabrics, and lyocell and viscose renewable cellulose fiber fabrics.

4. The high-efficiency inkjet dyeing process for reactive dyes according to claim 2, characterized in that, The immersion in the aqueous solution is carried out by one dip and one roll or two dips and two rolls, with the roll residue controlled between 60% and 120%. The aqueous solution contains a penetrant, which is one or more of sodium dodecyl sulfate, naphthalene sulfonate anionic penetrants, polyethylene glycol (molecular weight 200-600), and polyoxyethylene octylphenyl ether nonionic penetrants, and the amount added is 0-3 g / L.

5. The high-efficiency inkjet dyeing process for reactive dyes according to claim 2, characterized in that, The reactive dye ink has a viscosity of 3–10 mPa·s, a surface tension of 20–50 mN / m, and is available in four colors: C, M, Y, and K. The spraying amount is controlled at 5–30 g / m. 2 The nozzle resolution is ≥600 dpi.

6. The high-efficiency inkjet dyeing process for reactive dyes according to claim 1, characterized in that, The alkali solution is used to immerse the wet printing fabric in the alkali solution and then dry it. The immersion and padding method is one dip and one pad, and the padding rate is controlled at 65-120% to obtain the alkali-treated wet printing fabric.

7. The high-efficiency inkjet dyeing process for reactive dyes according to claim 6, characterized in that, The alkaline solution is not limited to sodium hydroxide solution, sodium bicarbonate solution, and sodium carbonate solution, and the mass fraction of the alkaline solution is 1% to 10%. The drying temperature is 60-70℃, and the time is 8-12 hours.

8. The high-efficiency inkjet dyeing process for reactive dyes according to claim 1, characterized in that, The steam color fixing process involves steam fixing the alkali-treated wet-printed fabric, followed by water washing to complete the color fixing.

9. The high-efficiency inkjet dyeing process for reactive dyes according to claim 8, characterized in that, The steam color-fixing process uses saturated steam at 100-102℃ for 5-15 minutes and a humidity of 90-98%.

10. The application of the high-efficiency inkjet dyeing process for reactive dyes as described in any one of claims 1-9, characterized in that, The application involves inkjet dyeing of different types of fabrics, with a K / S ratio ≥0.95 on the front and back sides of the dyed fabric, and color fastness of 4-5 or higher for dry rubbing, 4-5 for wet rubbing, and 4-5 for soap washing.

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