Processing method of digital ink-jet printing towel

Abstract

The invention relates to the technical field of towel production, in particular to a digital ink-jet printing towel processing method which comprises the following steps: S1, raw material selection: selecting a towel base material, ink-jet ink and a pretreatment agent, selecting high-water-absorption long stapled cotton yarns as the towel base material, selecting environment-friendly water-based disperse dye ink as the ink-jet ink, and performing pretreatment on the towel base material, the ink-jet ink and the pretreatment agent; a formaldehyde-free pretreatment agent is selected as a pretreatment agent; and S2, processing the raw materials, including S2-1, a pretreatment stage, S2-2, a digital ink-jet printing stage, S2-3, a color fixing stage and S2-4, a post-treatment stage. The printing effect, the color fastness, the pattern definition and the production efficiency are improved by improving a pretreatment process, ink jet equipment, printing material selection and a subsequent treatment process, and S2-1, in a pretreatment stage, a towel base material is immersed in a blended pretreatment agent solution, so that the ink affinity of fibers is enhanced. According to the method, a novel environment-friendly material and an advanced digital ink-jet technology are adopted, the printing processing process of the towel is optimized, and the production efficiency and the environment-friendly performance are improved.

Description

Technical Field

[0001] The invention relates to the technical field of towel production, in particular to a processing method of a digital inkjet printed towel. Background Art

[0002] With the rapid development of today's economy and the continuous progress of the textile industry at home and abroad, more and more advanced technologies are applied to our daily lives. In recent years, the application of digital inkjet printing has brought new forms and situations to our towel printing market, bringing us a new visual and sensory experience;

[0003] The printing process of traditional printed towel products is generally lengthy and complicated, and the wastewater, waste gas, water, electricity and gas generated during the printing process are relatively large, while the digital inkjet printing process is relatively short, so less wastewater is generated, which is more in line with our current environmental protection concept. However, the digital printing process of digitally printed towels requires very high precision in the positioning of the pattern, but existing towels are difficult to meet this requirement, so it is easy to have misprints and pattern deviations, which will cause batches of products to be scrapped; at the same time, the problem of positioning the pattern of digital inkjet printing on satin-edged products has always been a technical difficulty in the towel market;

[0004] The invention with the announcement number CN112609297B specifically discloses a production method of a satin-edged digital inkjet printed towel, and the specific production process is as follows: satin-edged towel design - pile cutting - towel pretreatment - pattern design - sizing - sizing - printing - drying - steaming - washing - drying - sewing and finishing; using high-definition and high-realistic printing technology, a pattern effect with a complete pattern is printed on the towel with a satin edge, and the pattern will not be offset when the pattern is printed in a continuous manner, and the position size deviation of the pattern on the front of each towel corresponding to the satin edge is very small, breaking through the technical difficulty of the pattern offset when the pattern is printed in a continuous manner, breaking the limitation that the traditional digital inkjet printing can only print ordinary towel products, and the appearance is more attractive to consumers;

[0005] However, due to the high water absorption and terry structure of textile towels, the production process of digital inkjet printing on towels can easily lead to uneven pattern penetration and low color fastness, which in turn causes low color fastness of the printing.

[0006] Therefore, a processing method of digital inkjet printed towel is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a processing method for digital inkjet printed towels, which improves the printing effect, color fastness, pattern clarity and production efficiency by improving the pre-treatment process, inkjet equipment, printing material selection and subsequent processing flow. The method will use new environmentally friendly materials and advanced digital inkjet technology to optimize the printing process of towels, improve production efficiency and environmental protection performance, so as to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a method for processing a digital inkjet printed towel, comprising the following steps:

[0009] S1. Raw material selection: towel substrate, inkjet ink and pre-treatment agent. The towel substrate is made of highly absorbent long-staple cotton yarn, the inkjet ink is environmentally friendly water-based disperse dye ink, and the pre-treatment agent is formaldehyde-free.

[0010] S2, raw material processing, including S2-1, pre-processing stage, S2-2, digital inkjet printing stage, S2-3, color fixing stage and S2-4, post-processing stage;

[0011] S2-1, pre-treatment stage, immersing the towel substrate in a prepared pre-treatment agent solution to enhance the ink affinity of the fiber, the pre-treatment agent solution contains a cross-linking agent and an adhesive, and then quickly drying the treated towel substrate at a temperature of 90°C to 110°C;

[0012] S2-2, digital inkjet printing stage, use high-resolution industrial-grade digital inkjet printing equipment for printing operations, the pattern resolution reaches more than 600dpi, and then use fine nozzle arrangement technology to automatically adjust the spray distance according to the height of the towel's terry loops to ensure uniform ink penetration and avoid pattern distortion caused by the terry loop structure;

[0013] S2-3, color fixing stage, using steam color fixing, the printed towel is placed in the steam color fixing equipment for treatment, and the dye molecules in the inkjet pattern are solidified by low-temperature steam at 90℃ to 120℃;

[0014] S2-4, post-processing stage, the towels are washed with low-temperature water to remove excess pre-treatment agents and uncured dyes, and an environmentally friendly softener is used for the final softening treatment. The washed towels are dried to an appropriate moisture content in a constant temperature drying device, and the towels are smoothed through a shaping device.

[0015] Preferably, the pretreatment agent solution in the pretreatment stage S2-1 includes nano-silicon dioxide and nano-alumina additives, and a micro-nano coating is formed on the surface of the towel substrate through the additives to reduce the difference in water absorption of the towels and ensure that the ink can penetrate evenly during inkjet.

[0016] Preferably, in the pre-treatment stage S2-1, oriented fiber finishing technology is used to orientedly arrange the fibers on the surface of the towel by mechanical and chemical means to reduce fiber interference during the printing process;

[0017] When mechanical oriented fiber finishing is adopted, a bidirectional combing structure is used to simultaneously arrange the fibers by upper and lower combs. Dynamic pressure regulation is adopted during the combing process of the combs. The mechanical pressure applied is dynamically adjusted according to the fiber characteristics, such as length, thickness and elasticity, by using a pressure control model.

[0018] Pressure control formula: F = k·A·ΔL, where F is the applied mechanical pressure, K is the elastic coefficient of the fiber, A is the surface area of ​​the fiber, and ΔL is the elongation of the fiber, that is, the change in length during stretching during the finishing process.

[0019] Preferably, a speed control model is used during the combing process of the carder, and the combing speed is optimized according to different fibers, by adjusting the combing speed;

[0020] The relationship between combing speed and fiber density is as follows:

[0021]

[0022] Where: v is the combing speed of the fiber, v0 is the standard combing speed, α is the adjustment coefficient, ρ f is the fiber density, ρ0 is the standard fiber density.

[0023] Preferably, when the fibers are oriented by chemical methods, a high molecular oriented finishing agent is introduced, such as a cationic polymer, to form a flexible coating on the fiber surface to help maintain a moderate repulsive force between the fibers. The cationic groups in the molecular chains of the finishing agent can combine with the surface charges of the fibers to increase the surface potential of the fibers, thereby forming a weak mutual repulsive force and making the fibers more neatly arranged.

[0024] The molecules in the finishing agent form a network structure on the fiber surface through a cross-linking reaction, thereby improving the stability of the fiber orientation arrangement. By optimizing the cross-linking agent and reaction conditions, the degree of the cross-linking reaction can be precisely controlled.

[0025] Crosslink density formula:

[0026]

[0027] Where: D crosslink is the crosslink density, C poly is the concentration of polymer in the finishing agent, R is the rate constant of the cross-linking reaction, and T is the processing temperature. By adjusting the finishing agent concentration and the processing temperature, the cross-linking reaction rate is optimized to ensure that a good orientation effect is achieved while maintaining the softness of the fiber.

[0028] Preferably, in the S2-1, pre-treatment stage, for the drying and curing stage of the treated towel substrate, a mathematical model of the thermal curing process is introduced to accurately control the curing temperature and time;

[0029] Thermal curing model formula:

[0030]

[0031] Where: G(T,t) is the function of curing effect, G0 is the curing ability of the initial finishing agent, E a is the activation energy, R is the gas constant, T is the curing temperature, and t is the curing time. According to the characteristics of different fibers and finishing agents, the thermal curing conditions are optimized to ensure that the effect of fiber directional arrangement is maintained for a long time.

[0032] Preferably, after the directional combing and chemical treatment are completed, the fiber is subjected to low tension stretching by mechanical stretching and shaping equipment, and the stretching formula is: σ=E·ε

[0033] Where: σ is the stress on the fiber, E is the elastic modulus of the fiber, and ε is the tensile strain of the fiber.

[0034] Preferably, the cationic polymer specifically comprises the following components in weight percentage:

[0035] 5wt%-10wt% of polydimethyldiallylammonium chloride, 3wt%-5wt% of cationic starch, 2wt%-4wt% of cationic guar gum and auxiliary ingredients.

[0036] Preferably, the auxiliary components include 1wt%-3wt% of softener, 0.5wt%-2wt% of cross-linking agent, 0.2wt%-1wt% of thickener, and 0.1wt%-0.5wt% of antistatic agent.

[0037] Preferably, the method for using the cationic polymer specifically includes:

[0038] C1. Add all ingredients into deionized water according to the proportion, first mix the thickener and water evenly, then gradually add cationic polymer, cationic starch, cationic guar gum and other additives, stir evenly, and make them completely dissolved;

[0039] C2. Use the prepared finishing agent solution for padding treatment of the fiber substrate. The fiber evenly absorbs the finishing agent solution through the padding machine to ensure that the fiber surface is completely covered with the finishing agent;

[0040] C3. Pre-dry the impregnated fibers at 60°C to 80°C, and then perform a low-temperature cross-linking and curing treatment at 80°C to 100°C to ensure that the finishing agent is evenly attached and forms a stable protective layer.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The processing technology of digital inkjet printed towels disclosed in this application, combined with high-resolution inkjet technology, environmentally friendly dyes and improvements in pre- and post-processing, can not only improve the color fastness and pattern clarity of the printing, but also greatly improve production efficiency and environmental performance. The innovation of this method lies in the comprehensive improvement of the inkjet process, pre-treatment and color fixing process, so that the overall quality of towel printing is significantly improved and meets the requirements of modern environmentally friendly production;

[0043] 2. Through further optimization of oriented fiber finishing technology, combined with mechanical combing and chemical treatment, a more uniform and stable fiber orientation effect can be achieved, improving the quality of inkjet printed towels. Through dynamic pressure control, intelligent speed adjustment, chemical cross-linking optimization and thermal curing treatment, not only can the clarity and color fastness of the printed pattern be improved, but also the softness and durability of the fiber can be improved. Combined with relevant mathematical models, the finishing effect of the fiber can be accurately controlled, making the process more efficient and controllable;

[0044] 3. The cationic polymer high molecular directional finishing agent can effectively enhance the directional arrangement of fibers by combining cationic polymers, natural starch and guar gum, and further improve the softness, directional stability and durability of fibers through softeners, cross-linking agents and other ingredients. The formula is environmentally friendly and non-toxic, can significantly improve the fiber finishing effect, and is suitable for digital inkjet printing processing of various textiles, especially materials with complex fiber structures such as highly absorbent towels. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 This is a flow chart of the processing method of the digital inkjet printed towel of the present invention;

[0047] Figure 2 A color fastness test table for the printed towel of the present invention;

[0048] Figure 3 A resolution test table for a printed towel of the present invention;

[0049] Figure 4 The color time and color fastness test table of the present invention;

[0050] Figure 5 This is a test chart of the intelligent inkjet technology and pattern clarity of the present invention;

[0051] Figure 6 This is a cationic polymer ratio table of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] See also Figures 1 to 6 , the present invention provides a technical solution:

[0054] A method for processing a digital inkjet printed towel comprises the following steps:

[0055] S1. Raw material selection: towel substrate, inkjet ink and pre-treatment agent. The towel substrate is made of highly absorbent long-staple cotton yarn, which has good water absorption and softness, and is easy to be chemically pre-treated to improve the inkjet effect. The inkjet ink is an environmentally friendly water-based disperse dye ink, which can improve the permeability of the fiber while maintaining the color brightness and fastness. The ink does not contain toxic heavy metals and volatile organic compounds. The pre-treatment agent is a formaldehyde-free pre-treatment agent to enhance the adsorption of the towel fiber to the inkjet ink, while avoiding the formaldehyde residue problem in traditional pre-treatment agents.

[0056] S2, raw material processing, including S2-1, pre-processing stage, S2-2, digital inkjet printing stage, S2-3, color fixing stage and S2-4, post-processing stage;

[0057] S2-1, pre-treatment stage, immersing the towel substrate in the prepared pre-treatment agent solution to enhance the ink affinity of the fiber. The pre-treatment agent solution contains a cross-linking agent and an adhesive to ensure uniform adhesion of the dye on the surface of the towel fiber. The treated towel substrate is then quickly dried at a temperature of 90°C to 110°C to ensure that the pre-treatment agent on the fiber surface is evenly distributed and does not affect the subsequent inkjet effect;

[0058] S2-2, digital inkjet printing stage, using high-resolution industrial-grade digital inkjet printing equipment for printing operations, the pattern resolution reaches more than 600dpi, suitable for complex patterns and gradient effects, and then using fine nozzle arrangement technology to automatically adjust the spray distance according to the height of the towel's terry loops to ensure uniform ink penetration and avoid pattern distortion caused by the terry loop structure;

[0059] S2-3, color fixing stage, steam color fixing is used, the printed towel is placed in the steam color fixing equipment for processing, low-temperature steam at 90℃ to 120℃ is used to solidify the dye molecules in the inkjet pattern, improve the bonding strength between the dye and the fiber, and enhance the color fastness. The color fixing technology combining low-temperature steam and microwave is used, and microwave assisted heating is introduced on the basis of steam color fixing. Microwave heating can effectively shorten the color fixing time and improve the color fastness without destroying the fiber structure. Specific parameters: low-temperature steam temperature is controlled at 85℃-100℃, microwave color fixing time is 3-5 minutes, achieving rapid color fixing with low energy consumption. Through the double color fixing process, the dye molecules can be fixed to the fiber at a deeper level, improving color fastness, especially the durability under washing and friction conditions;

[0060] S2-4, in the post-processing stage, the towels are washed with low-temperature water to remove excess pre-treatment agents and uncured dyes, and an environmentally friendly softener is used for the final softening treatment to ensure that the towels maintain their original softness and comfortable touch. The washed towels are dried to an appropriate moisture content in a constant temperature drying device, and at the same time, the towels are smoothed through a shaping device to avoid curling and deformation.

[0061] The processing technology of digital inkjet printed towels disclosed in this application, combined with high-resolution inkjet technology, environmentally friendly dyes and improvements in pre- and post-processing, can not only improve the color fastness and pattern clarity of the printing, but also greatly improve production efficiency and environmental performance. The innovation of this method lies in the comprehensive improvement of the inkjet process, pre-treatment and color fixing process, so that the overall quality of towel printing is significantly improved and meets the requirements of modern environmentally friendly production;

[0062] Specifically, the pretreatment agent solution in the S2-1 pretreatment stage includes nano-silicon dioxide and nano-alumina additives, and a micro-nano coating is formed on the surface of the towel substrate through the additives to reduce the difference in water absorption of the towels and ensure that the ink can penetrate evenly during inkjet.

[0063] Specifically, in the S2-1, pre-treatment stage, directional fiber finishing technology is used to align the fibers on the surface of the towel mechanically and chemically to reduce fiber interference during the printing process. Directed fiber arrangement can reduce fiber interference during the printing process, making the inkjet printing effect clearer and more delicate. The towel fibers are slightly pre-treated through pre-pressing technology to keep the fibers flat. In order to achieve more complex colors and gradient effects, multi-level gradient inkjet technology is introduced. This technology uses nozzles of different diameters to be arranged in a staggered manner, and multi-level ink jetting is performed according to preset patterns and color depths to ensure smooth transitions of gradient colors and high-resolution performance. The nozzle should have three-dimensional fine-tuning capabilities and can flexibly switch between multiple color levels according to pattern requirements to achieve precise control;

[0064] When mechanical oriented fiber finishing is adopted, a bidirectional combing structure is used to simultaneously arrange the fibers by upper and lower combs. Dynamic pressure regulation is adopted during the combing process of the combs. The mechanical pressure applied is dynamically adjusted according to the fiber characteristics, such as length, thickness and elasticity, by using a pressure control model.

[0065] Pressure control formula: F = k·A·ΔL, where F is the applied mechanical pressure, K is the elastic coefficient of the fiber, A is the surface area of ​​the fiber, and ΔL is the elongation of the fiber, that is, the change in length during stretching during the finishing process.

[0066] Specifically, a speed control model is used in the combing process of the carder to optimize the combing speed according to different fibers, by adjusting the combing speed;

[0067] The relationship between combing speed and fiber density is as follows:

[0068]

[0069] Where: v is the combing speed of the fiber, v0 is the standard combing speed, α is the adjustment coefficient, ρ f is the fiber density, ρ0 is the standard fiber density.

[0070] Specifically, when the fibers are chemically oriented, a high molecular weight oriented finishing agent is introduced, such as a cationic polymer, to form a flexible coating on the fiber surface to help maintain a moderate repulsive force between the fibers. The cationic groups in the molecular chain of the finishing agent can combine with the surface charge of the fiber to increase the surface potential of the fiber, thereby forming a weak mutual repulsive force and making the fibers more neatly arranged.

[0071] The molecules in the finishing agent form a network structure on the fiber surface through a cross-linking reaction, thereby improving the stability of the fiber orientation arrangement. By optimizing the cross-linking agent and reaction conditions, the degree of the cross-linking reaction can be accurately controlled to ensure that the fiber surface does not become rigid due to excessive cross-linking.

[0072] Crosslink density formula:

[0073]

[0074] Where: D crosslink is the crosslink density, C poly is the concentration of polymer in the finishing agent, R is the rate constant of the cross-linking reaction, and T is the processing temperature. By adjusting the finishing agent concentration and the processing temperature, the cross-linking reaction rate is optimized to ensure that a good orientation effect is achieved while maintaining the softness of the fiber.

[0075] By further optimizing the oriented fiber finishing technology, combined with mechanical combing and chemical treatment, a more uniform and stable fiber orientation effect can be achieved, improving the quality of inkjet printed towels. Through dynamic pressure control, intelligent speed adjustment, chemical cross-linking optimization and thermal curing treatment, not only can the clarity and color fastness of the printed pattern be improved, but also the softness and durability of the fiber can be improved. Combined with relevant mathematical models, the finishing effect of the fiber can be accurately controlled, making the process more efficient and controllable;

[0076] The fibers are oriented and solidified to make them more stable. Heat setting or UV curing can be used to create a lasting finishing effect on the fiber surface, reducing fiber shrinkage or deformation.

[0077] Specifically, in the S2-1, pre-treatment stage, for the drying and curing stage of the treated towel substrate, a mathematical model of the thermal curing process is introduced to accurately control the curing temperature and time to ensure that the finishing effect of the fiber is not destroyed during subsequent processing and use;

[0078] Thermal curing model formula:

[0079]

[0080] Where: G(T,t) is the function of curing effect, G0 is the curing ability of the initial finishing agent, E a is the activation energy, R is the gas constant, T is the curing temperature, and t is the curing time. According to the characteristics of different fibers and finishing agents, the thermal curing conditions are optimized to ensure that the effect of fiber directional arrangement is maintained for a long time.

[0081] Specifically, after directional combing and chemical treatment, the fibers are stretched at low tension through mechanical stretching and shaping equipment to further ensure the directional arrangement of the fibers and prevent the fibers from shrinking and deforming during the subsequent inkjet printing process. The stretching formula is: σ = E·ε

[0082] Where: σ is the stress on the fiber, E is the elastic modulus of the fiber, and ε is the tensile strain of the fiber.

[0083] Specifically, the cationic polymer comprises the following components in weight percentage:

[0084] The main function of polymer directional finishing agents is to form a thin film on the fiber surface to help the fibers align, increase the repulsive force between fibers, prevent entanglement, and improve the softness and directional effect of the fibers. In cationic polymer directional finishing agents, cationic groups are usually used to interact with the negative charges on the fiber surface to form a stable adsorption and action.

[0085] Polydimethyldiallylammonium chloride 5wt%-10wt%, a commonly used water-soluble cationic polymer, has excellent adsorption capacity and can be effectively adsorbed on the negatively charged fiber surface to help the fibers align. It enhances the repulsive force between fibers through electrostatic action and improves fiber orientation

[0086] Cationic starch 3wt%-5wt%, by chemically modifying starch, cationic groups are introduced into the starch molecular chain to form weak chemical bonds with the fiber surface. Cationic starch has good biodegradability and flexibility, and is suitable as a natural finishing agent.

[0087] Cationic guar gum 2wt%-4wt%, by reacting the hydroxyl group of guar gum with quaternary ammonium salt to introduce cationic groups, it has good adsorption and thickening effects. It can form a protective film on the fiber surface, enhance the orientation effect and improve the feel of the fiber.

[0088] Auxiliary ingredients.

[0089] Specifically, the auxiliary ingredients include:

[0090] Softener 1wt%-3wt%, polyether softener. In order to maintain the softness of the fiber, a small amount of polyether softener, such as polyethylene glycol, can be added. Polyethylene glycol has good water solubility and softening properties, which helps to maintain the comfort of the fiber and enhance its surface smoothness.

[0091] Crosslinking agent 0.5wt%-2wt%, glyoxal or glutaraldehyde, as a crosslinking agent, during the finishing process, the crosslinking agent combines with the fiber surface through chemical reaction to form a stable chemical bond, further enhancing the directional arrangement effect of the fiber and improving the fiber's washability and wear resistance.

[0092] Thickener 0.2wt%-1wt%, carboxymethyl cellulose, ensures that the finishing agent is evenly coated on the fiber surface, and a small amount of thickener is added to increase the viscosity of the solution so that the finishing agent can be evenly distributed.

[0093] Antistatic agent 0.1wt%-0.5wt%, quaternary ammonium salt antistatic agent is used to further reduce static electricity accumulation on the fiber surface, enhance the repulsive force between fibers, and avoid fiber entanglement.

[0094] Specifically, the method for using the cationic polymer includes:

[0095] C1. Add all ingredients into deionized water according to the proportion, first mix the thickener and water evenly, then gradually add cationic polymer, cationic starch, cationic guar gum and other additives, stir evenly, and make them completely dissolved;

[0096] C2. Use the prepared finishing agent solution for padding treatment of the fiber substrate. The fiber evenly absorbs the finishing agent solution through the padding machine to ensure that the fiber surface is completely covered with the finishing agent;

[0097] C3. Pre-dry the impregnated fibers at 60°C to 80°C, and then perform a low-temperature cross-linking and curing treatment at 80°C to 100°C to ensure that the finishing agent is evenly attached and forms a stable protective layer.

[0098] The cationic polymer high molecular directional finishing agent can effectively enhance the directional arrangement of fibers by combining cationic polymers, natural starch and guar gum, and further improve the softness, directional stability and durability of fibers through softeners, cross-linking agents and other ingredients. The formula is environmentally friendly and non-toxic, can significantly improve the fiber finishing effect, and is suitable for digital inkjet printing processing of various textiles, especially materials with complex fiber structures such as highly absorbent towels.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for processing digital inkjet printed towels, characterized in that: The steps include: S1. Raw material selection: towel substrate, inkjet ink and pre-treatment agent. The towel substrate is made of highly absorbent long-staple cotton yarn, the inkjet ink is environmentally friendly water-based disperse dye ink, and the pre-treatment agent is formaldehyde-free. S2, raw material processing, including S2-1, pre-processing stage, S2-2, digital inkjet printing stage, S2-3, color fixing stage and S2-4, post-processing stage; S2-1, pre-treatment stage, immersing the towel substrate in a prepared pre-treatment agent solution to enhance the ink affinity of the fiber, the pre-treatment agent solution contains a cross-linking agent and an adhesive, and then quickly drying the treated towel substrate at a temperature of 90°C to 110°C; S2-2, digital inkjet printing stage, use high-resolution industrial-grade digital inkjet printing equipment for printing operations, the pattern resolution reaches more than 600dpi, and then use fine nozzle arrangement technology to automatically adjust the spray distance according to the height of the towel's terry loops to ensure uniform ink penetration and avoid pattern distortion caused by the terry loop structure; S2-3, color fixing stage, using steam color fixing, the printed towel is placed in the steam color fixing equipment for treatment, and the dye molecules in the inkjet pattern are solidified by low-temperature steam at 90℃ to 120℃; S2-4, post-processing stage, the towels are washed with low-temperature water to remove excess pre-treatment agents and uncured dyes, and an environmentally friendly softener is used for the final softening treatment. The washed towels are dried to an appropriate moisture content in a constant temperature drying device, and the towels are smoothed through a shaping device.

2. The method for processing a digital inkjet printed towel according to claim 1, characterized in that: The pretreatment agent solution in the pretreatment stage S2-1 includes nano-silicon dioxide and nano-alumina additives, and the additives form a micro-nano coating on the surface of the towel substrate to reduce the difference in water absorption of the towels and ensure that the ink can penetrate evenly during inkjet.

3. The method for processing a digital inkjet printed towel according to claim 2, characterized in that: In the pre-treatment stage S2-1, oriented fiber finishing technology is used to orientedly arrange the fibers on the surface of the towel by mechanical and chemical means to reduce fiber interference during the printing process; When mechanical oriented fiber finishing is adopted, a bidirectional combing structure is used to simultaneously arrange the fibers by upper and lower combs. Dynamic pressure regulation is adopted during the combing process of the combs. The mechanical pressure applied is dynamically adjusted according to the fiber characteristics, such as length, thickness and elasticity, by using a pressure control model. Pressure control formula: F = k·A·ΔL, where F is the applied mechanical pressure, K is the elastic coefficient of the fiber, A is the surface area of ​​the fiber, and ΔL is the elongation of the fiber, that is, the change in length during stretching during the finishing process.

4. The method for processing a digital inkjet printed towel according to claim 3, characterized in that: The speed control model is used in the combing process of the carder to optimize the combing speed according to different fibers by adjusting the combing speed; The relationship between combing speed and fiber density is as follows: Where: v is the combing speed of the fiber, v0 is the standard combing speed, α is the adjustment coefficient, ρ f is the fiber density, ρ0 is the standard fiber density.

5. The method for processing a digital inkjet printed towel according to claim 3, characterized in that: When the fibers are oriented by chemical methods, a high molecular oriented finishing agent is introduced, such as a cationic polymer, to form a flexible coating on the fiber surface to help maintain a moderate repulsive force between the fibers. The cationic groups in the molecular chain of the finishing agent can combine with the surface charge of the fiber to increase the surface potential of the fiber, thereby forming a weak mutual repulsive force and making the fibers more neatly arranged. The molecules in the finishing agent form a network structure on the fiber surface through a cross-linking reaction, thereby improving the stability of the fiber orientation arrangement. By optimizing the cross-linking agent and reaction conditions, the degree of the cross-linking reaction can be precisely controlled. Crosslink density formula: Where: D crosslink is the crosslink density, C poly is the concentration of polymer in the finishing agent, R is the rate constant of the cross-linking reaction, and T is the processing temperature. By adjusting the finishing agent concentration and the processing temperature, the cross-linking reaction rate is optimized to ensure that a good orientation effect is achieved while maintaining the softness of the fiber.

6. The method for processing a digital inkjet printed towel according to claim 5, characterized in that: In the S2-1, pre-treatment stage, for the drying and curing stage of the treated towel substrate, a mathematical model of the thermal curing process is introduced to accurately control the curing temperature and time; Thermal curing model formula: Where: G(T,t) is the function of curing effect, G0 is the curing ability of the initial finishing agent, E a is the activation energy, R is the gas constant, T is the curing temperature, and t is the curing time. According to the characteristics of different fibers and finishing agents, the thermal curing conditions are optimized to ensure that the effect of fiber directional arrangement is maintained for a long time.

7. The method for processing a digital inkjet printed towel according to claim 6, characterized in that: After directional combing and chemical treatment, the fiber is stretched at low tension by mechanical stretching and shaping equipment. The stretching formula is: σ=E·ε Where: σ is the stress on the fiber, E is the elastic modulus of the fiber, and ε is the tensile strain of the fiber.

8. The method for processing a digital inkjet printed towel according to claim 5, characterized in that: The cationic polymer specifically comprises the following components in weight percentage: 5wt%-10wt% of polydimethyldiallylammonium chloride, 3wt%-5wt% of cationic starch, 2wt%-4wt% of cationic guar gum and auxiliary ingredients.

9. The method for processing a digital inkjet printed towel according to claim 8, characterized in that: The auxiliary components include 1wt%-3wt% of a softener, 0.5wt%-2wt% of a cross-linking agent, 0.2wt%-1wt% of a thickener, and 0.1wt%-0.5wt% of an antistatic agent.

10. The method for processing a digital inkjet printed towel according to claim 9, characterized in that: The method for using the cationic polymer specifically includes: C1. Add all ingredients into deionized water according to the proportion, first mix the thickener and water evenly, then gradually add cationic polymer, cationic starch, cationic guar gum and other additives, stir evenly, and make them completely dissolved; C2. Use the prepared finishing agent solution for padding treatment of the fiber substrate. The fiber evenly absorbs the finishing agent solution through the padding machine to ensure that the fiber surface is completely covered with the finishing agent; C3. Pre-dry the impregnated fibers at 60°C to 80°C, and then perform a low-temperature cross-linking and curing treatment at 80°C to 100°C to ensure that the finishing agent is evenly attached and forms a stable protective layer.

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