Silk digital printing gradient bleeding control method based on ultrasonic cavitation regulation and control
By combining multi-band ultrasonic fields with inks of different viscosities, the problem of uneven color bleeding in digital silk printing was solved, achieving a balance between pattern clarity and fiber property protection, resulting in a highly efficient printing effect.
Patent Information
- Application Number
- CN202511758242.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-01-23
AI Technical Summary
Traditional digital printing technology for silk struggles to achieve both full penetration in the center of the pattern and sharp, clear edges, resulting in insufficient color gain in dark areas or severe bleeding in light areas. Furthermore, chemical modification methods may damage fiber properties.
By employing a multi-band composite ultrasonic field (28kHz/1.2W/cm2 in the edge region, 100kHz/0.3W/cm2 in the center region, and 45kHz/0.8W/cm2 in the transition region) combined with reactive dye inks of different viscosities (8-12mPa·s, 2-4mPa·s, and 5-7mPa·s), and through ultrasonic cavitation pretreatment and a step-by-step color-fixing process, differentiated control of silk fabrics can be achieved.
It achieves a pattern edge bleeding width of less than 0.2mm, a dye penetration depth in the central area reaching more than 90% of the fiber cross-section, a uniform color gradient in the transition area, a 60% improvement in pattern clarity, a fiber strength retention rate of more than 95%, and a softness retention rate of more than 90%.
Abstract
Description
Technical Field
[0001] This invention relates to the field of silk processing technology, specifically to a method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation. Background Technology
[0002] Digital printing on silk is a key technology for enhancing the added value of silk products, but its development has long been limited by the problem of "bleed-through" in printed patterns. Due to the smooth surface and strong hydrophilicity of silk fibers, in the traditional digital printing process, the dye ink will spread uncontrollably from the edge of the pattern to the outer area under the action of capillary effect, resulting in blurred pattern outlines and reduced clarity, and in particular, it is difficult to achieve fine patterns and color gradient effects.
[0003] In existing technologies, two main methods are used to solve the problem of color bleeding: one is to build a hydrophobic barrier on the surface of silk fibers through chemical modification, such as using fluorinated finishing agents or cross-linking agents. However, this method often changes the skin-friendly feel of silk and may introduce chemicals that do not meet the requirements of ecological textiles. The other is to adjust the ink formula, such as increasing the ink viscosity or adding thickeners. However, inks with a single viscosity are difficult to simultaneously meet the dual requirements of sufficient penetration in the center area of the pattern and sharp and clear edge areas, often resulting in insufficient color gain in dark areas or severe color bleeding in light areas.
[0004] In recent years, researchers have attempted to utilize physical field-assisted printing techniques. For example, they have pretreated silk with ultrasound at a single frequency to improve its dyeing properties. However, ultrasound treatment with a single parameter applied to the entire fabric cannot achieve differentiated control over different areas of the pattern; instead, uneven treatment may exacerbate the uncontrollable bleeding. How to precisely control the partitioning and directional penetration of dye within silk fibers to achieve a printing effect of "sharp edges, vibrant center, and natural transitions," while maintaining the inherent excellent properties of silk, remains a long-standing technical bottleneck in this field. Summary of the Invention
[0005] The purpose of this invention is to provide a gradient bleeding control method for digital silk printing using ultrasonic cavitation regulation, which aims to solve the problem that traditional techniques cannot simultaneously meet the dual requirements of sufficient penetration in the center area of the pattern and sharp and clear edge areas, resulting in insufficient color gain in dark areas or severe bleeding in light areas.
[0006] Based on this, the present invention proposes a method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation. The method includes: S1, immersing the silk fabric in a pretreatment solution containing 0.5-2wt% silk fibroin and 0.1-0.5wt% nano zinc oxide, at a frequency of 40kHz and a power density of 0.5W / cm². 2S2. Apply ultrasonic fields with different parameters to the corresponding areas according to the outline of the preset printing pattern. Specifically, apply ultrasonic fields with parameters of 28kHz and 1.2W / cm² to the edge area of the pattern. 2 The ultrasound was applied to the central area at 100 kHz and 0.3 W / cm². 2 The ultrasound was applied at 45 kHz and 0.8 W / cm² in the transition zone. 2 S3. Apply ultrasonic treatment for 1-3 minutes, according to the cavitation control area determined in step S2. Specifically: use high-viscosity ink (8-12 mPa·s) for the edge area, low-viscosity ink (2-4 mPa·s) for the center area, and medium-viscosity ink (5-7 mPa·s) for the transition area; S4. First, apply the treatment at a frequency of 25 kHz and a power density of 0.6 W / cm². 2 Pre-fixation was performed under ultrasonic assistance, followed by steam fixation at 102-105℃ for 10-20 minutes.
[0007] In some embodiments, in step S1, the nano-zinc oxide has a particle size of 20-50 nm and its surface is modified with a silane coupling agent.
[0008] In some embodiments, in step S2, the ultrasonic treatment time for the pattern edge area is 2-3 minutes, for the center area it is 1-1.5 minutes, and for the transition area it is 1.5-2 minutes.
[0009] In some embodiments, in step S3, the high-viscosity ink further comprises 0.5-1.5 wt% hydroxyethyl cellulose, the low-viscosity ink comprises 0.1-0.5 wt% polyvinylpyrrolidone, and the medium-viscosity ink comprises 0.3-0.8 wt% sodium alginate. The viscosity of the high-viscosity ink is 8-12 mPa·s, the viscosity of the low-viscosity ink is 2-4 mPa·s, and the viscosity of the medium-viscosity ink is 5-7 mPa·s.
[0010] In some embodiments, in step S4, the ultrasonic-assisted pre-fixation time is 3-5 minutes, and the temperature is controlled at 40-50°C.
[0011] In some embodiments, in step S2, when an ultrasonic field is applied, the fabric tension is maintained at 2-5 N / cm.
[0012] In some embodiments, in step S3, when applying reactive dye ink, the printing resolution is 600-1200 dpi.
[0013] In some embodiments, the relative humidity is maintained at 95-100% during the steam fixation process in step S4.
[0014] In some embodiments, the method further includes: S5, applying a color-fixing solution at a frequency of 35 kHz and a power density of 0.4 W / cm². 2 The water is washed with ultrasound at a temperature of 40-50℃ for 5-10 minutes.
[0015] Compared with the prior art, the present invention has the following advantages: 1. The present invention uses a multi-band composite ultrasonic field (edge region 28kHz / 1.2W / cm) 2 , Central region 100kHz / 0.3W / cm 2 Transition region 45kHz / 0.8W / cm 2 The differentiated processing, combined with the synergistic effect of inks of corresponding viscosities (8-12mPa·s, 2-4mPa·s, 5-7mPa·s), achieves a pattern edge bleeding width of less than 0.2mm, a dye penetration depth in the central area reaching more than 90% of the fiber cross-section, and a uniform color gradient effect in the transition area, effectively solving the problems of edge blurring and bleeding in traditional printing.
[0016] 2. The ultrasonic cavitation pretreatment of this invention enables silk fibroin and nano-zinc oxide to form a uniform distribution within the fiber, providing more binding sites for the dye. This increases the dye fixation rate from 82% in traditional methods to over 96%. The step-by-step fixation process ensures more complete covalent bonding between the reactive dye and the fiber, achieving a wet rubbing fastness of 4-5 and a wash fastness of 4 or higher.
[0017] 3. Silk printed products treated with this invention exhibit approximately 60% improved pattern outline clarity, edge sharpness reaching level 4.8 (out of 5), and significantly enhanced color gradation. Particularly for fine lines and color gradient patterns, line width deviation is controlled within ±0.1mm, and the color difference gradient ΔE in color transition areas is uniform with no obvious color breakage. Furthermore, due to the adoption of a physical field-based control technology, damage to fibers caused by strong chemical modification is avoided. The treated silk fabric retains over 95% of its tensile strength, over 90% of its softness, and only about 5% of its breathability, fully preserving the unique skin-friendly feel and drape of silk. Detailed Implementation
[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0019] Example 1: This example provides a method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation. The method includes: S1, immersing silk fabric in a pretreatment solution containing 1.2wt% silk fibroin and 0.3wt% nano zinc oxide (particle size 35nm, modified with silane coupling agent KH-550), at a frequency of 40kHz and a power density of 0.5W / cm². 2 S2. Apply ultrasonic field to the printing area according to the preset printing pattern outline: apply 28kHz, 1.2W / cm² ultrasonic field to the edge area. 2 Ultrasonic treatment for 2.5 minutes, with a central area treated at 100 kHz and 0.3 W / cm². 2 Ultrasonic treatment for 1.2 minutes, with a transition zone treated at 45 kHz and 0.8 W / cm. 2 Ultrasonic treatment for 1.8 minutes, maintaining fabric tension at 3.5 N / cm during treatment; S3, apply reactive dye ink according to the cavitation control area: use ink with a viscosity of 10 mPa·s (containing 1.0 wt% hydroxyethyl cellulose) for the edge area, ink with a viscosity of 3 mPa·s (containing 0.3 wt% polyvinylpyrrolidone) for the center area, and ink with a viscosity of 6 mPa·s (containing 0.5 wt% sodium alginate) for the transition area, setting the printing resolution to 900 dpi; S4, first at a frequency of 25 kHz and a power density of 0.6 W / cm². 2 S5. Ultrasonic pre-curing at 45℃ for 4 minutes, followed by steam curing at 103℃ and 98% relative humidity for 15 minutes; S6. After curing, a frequency of 35kHz and a power density of 0.4W / cm³ were used. 2 The water was washed with ultrasound at a temperature of 45°C for 8 minutes.
[0020] Performance tests were performed on the product obtained in Example 1: Edge bleeding width (GB / T 23331-2009): 0.18 mm; Dye penetration depth in the central area (AATCC 130-2010): 92%; Color gradient uniformity in the transition area (GB / T7921-2008): ΔE=1.8; Dye fixation rate (GB / T 3920-2008): 96.8%; Wet rubbing fastness (GB / T 3920-2008): Grade 4-5; Washing fastness (GB / T 3921-2008): Grade 4.5; Pattern clarity rating (ISO 16545-2014): 4.8 / 5.0; Fiber strength retention rate (GB / T 3923.1-2013): 95.2%; Hand softness retention rate (ASTM D4964-1996): 93.5%.
[0021] Example 2: This example is basically the same as Example 1, except that the method is adjusted as follows: S1, 1.8wt% silk fibroin and 0.4wt% nano zinc oxide (particle size 25nm) are treated for 4.5 minutes; S2, the edge area is treated for 3 minutes, the center area for 1 minute, and the transition area for 2 minutes, with a fabric tension of 4.5 N / cm; S3, the ink viscosity in the edge area is 11 mPa·s (containing 1.3wt% hydroxyethyl cellulose), the ink viscosity in the center area is 2.5 mPa·s (containing 0.2wt% polyvinylpyrrolidone), and the ink viscosity in the transition area is 5.5 mPa·s (containing 0.7wt% sodium alginate), with a printing resolution of 1200 dpi; S4, ultrasonic pre-fixing for 4.5 minutes (temperature 48℃) and steam fixing for 18 minutes (104℃, relative humidity 99%); S5, ultrasonic washing for 10 minutes (temperature 48℃).
[0022] The product obtained in Example 2 was subjected to performance tests: edge bleeding width (GB / T 23331-2009): 0.12 mm, central area dye penetration depth (AATCC 130-2010): 88%, uniformity of color difference gradient in transition area (GB / T7921-2008): ΔE=1.2, dye fixation rate (GB / T 3920-2008): 97.5%, wet rubbing fastness (GB / T 3920-2008): Grade 5, wash fastness (GB / T 3921-2008): Grade 5, pattern clarity rating (ISO 16545-2014): 4.9 / 5.0, fiber strength retention rate (GB / T 3923.1-2013): 93.8%, hand softness retention rate (ASTM D4964-1996): 91.2%.
[0023] Example 3: This example is basically the same as Example 1, except that the method is adjusted as follows: S1: 0.8wt% silk fibroin, 0.2wt% nano zinc oxide (particle size 45nm), treatment for 2.5 minutes; S2: 2 minutes for edge area treatment, 1.5 minutes for center area treatment, 1.5 minutes for transition area treatment, fabric tension 2.5N / cm; S3: 9mPa·s ink viscosity for edge area (containing 0.7wt% hydroxyethyl cellulose), 3.5mPa·s ink viscosity for center area (containing 0.4wt% polyvinylpyrrolidone), 6.5mPa·s ink viscosity for transition area (containing 0.4wt% sodium alginate), printing resolution 600dpi; S4: 3 minutes of ultrasonic pre-fixing (temperature 42℃), 12 minutes of steam fixing (102℃, relative humidity 96%); S5: 6 minutes of ultrasonic water washing (temperature 42℃).
[0024] The product obtained in Example 3 was subjected to performance tests: edge bleeding width (GB / T 23331-2009): 0.25 mm, central area dye penetration depth (AATCC 130-2010): 85%, uniformity of color difference gradient in transition area (GB / T7921-2008): ΔE=2.3, dye fixation rate (GB / T 3920-2008): 94.3%, wet rubbing fastness (GB / T 3920-2008): Grade 4, wash fastness (GB / T 3921-2008): Grade 4, pattern clarity rating (ISO 16545-2014): 4.5 / 5.0, fiber strength retention rate (GB / T 3923.1-2013): 96.5%, hand softness retention rate (ASTM D4964-1996): 95.8%.
[0025] Comparative Example 1: This comparative example is basically the same as Example 1, except that a uniform 45kHz, 0.8W / cm² voltage is applied to the entire patterned area in step S2. 2 Ultrasonic treatment for 2 minutes.
[0026] Performance tests were conducted on the product obtained in Comparative Example 1: Edge bleeding width (GB / T 23331-2009): 0.65 mm; Dye penetration depth in the center area (AATCC 130-2010): 78%; Color gradient uniformity in the transition area (GB / T7921-2008): ΔE=4.8; Dye fixation rate (GB / T 3920-2008): 87.9%; Wet rubbing fastness (GB / T 3920-2008): Grade 3; Washing fastness (GB / T 3921-2008): Grade 4; Pattern clarity rating (ISO 16545-2014): 3.2 / 5.0; Fiber strength retention rate (GB / T 3923.1-2013): 81.6%; Hand softness retention rate (ASTM D4964-1996): 84.3%.
[0027] Comparative Example 2: This comparative example is basically the same as Example 1, except that in step S3, a single ink with a viscosity of 6 mPa·s (containing 0.5 wt% sodium alginate) was used.
[0028] Performance tests were conducted on the product obtained in Comparative Example 2: Edge bleeding width (GB / T 23331-2009): 0.52 mm; Dye penetration depth in the central area (AATCC 130-2010): 82%; Color gradient uniformity in the transition area (GB / T7921-2008): ΔE=3.5; Dye fixation rate (GB / T 3920-2008): 89.5%; Wet rubbing fastness (GB / T 3920-2008): Grade 3; Washing fastness (GB / T 3921-2008): Grade 3; Pattern clarity rating (ISO 16545-2014): 3.5 / 5.0; Fiber strength retention rate (GB / T 3923.1-2013): 82.6%; Hand softness retention rate (ASTM D4964-1996): 83.8%.
[0029] Comparative Example 3: This comparative example is basically the same as Example 1, except that nano zinc oxide is removed in step S1 and only 1.2 wt% silk fibroin is used.
[0030] Performance tests were conducted on the product obtained in Comparative Example 3: Edge bleeding width (GB / T 23331-2009): 0.45 mm; Dye penetration depth in the central area (AATCC 130-2010): 75%; Color difference gradient uniformity in the transition area (GB / T7921-2008): ΔE=4.5; Dye fixation rate (GB / T 3920-2008): 84.3%; Wet rubbing fastness (GB / T 3920-2008): Grade 3; Washing fastness (GB / T 3921-2008): Grade 3; Pattern clarity rating (ISO 16545-2014): 3.7 / 5.0; Fiber strength retention rate (GB / T 3923.1-2013): 80.6%; Hand softness retention rate (ASTM D4964-1996): 81.5%.
[0031] Comparative Example 4: This comparative example is basically the same as Example 1, except that the ultrasonic field is removed in step S1 and the soaking treatment is only 3.5 minutes.
[0032] Performance tests were conducted on the product obtained in Comparative Example 4: Edge bleeding width (GB / T 23331-2009): 0.78 mm; Dye penetration depth in the central area (AATCC 130-2010): 72%; Color gradient uniformity in the transition area (GB / T7921-2008): ΔE=4.2; Dye fixation rate (GB / T 3920-2008): 81.5%; Wet rubbing fastness (GB / T 3920-2008): Grade 3; Washing fastness (GB / T 3921-2008): Grade 3; Pattern clarity rating (ISO 16545-2014): 3.4 / 5.0; Fiber strength retention rate (GB / T 3923.1-2013): 82.5%; Hand softness retention rate (ASTM D4964-1996): 83.4%.
[0033] Comparative Example 5: This comparative example is basically the same as Example 1, except that it uses conventional alkali pretreatment + single viscosity ink (4 mPa·s) + conventional steam fixation.
[0034] Performance tests were conducted on the product obtained in Comparative Example 5: Edge bleeding width (GB / T 23331-2009): 0.95 mm; Dye penetration depth in the central area (AATCC 130-2010): 68%; Color gradient uniformity in the transition area (GB / T7921-2008): ΔE=4.9; Dye fixation rate (GB / T 3920-2008): 81.3%; Wet rubbing fastness (GB / T 3920-2008): Grade 3; Washing fastness (GB / T 3921-2008): Grade 3; Pattern clarity rating (ISO 16545-2014): 2.8 / 5.0; Fiber strength retention rate (GB / T 3923.1-2013): 78.6%; Hand softness retention rate (ASTM D4964-1996): 79.4%.
[0035] Results Analysis: 1. The edge bleeding width of Examples 1-3 showed a significant negative correlation with the pattern sharpness score: the smaller the bleeding width, the higher the sharpness score. Example 2 had the smallest bleeding width (0.12mm) and the highest sharpness score (4.9), proving that bleeding control is a key factor affecting pattern quality.
[0036] 2. There is a positive correlation between the penetration depth in the central area and the wet rubbing fastness. In Example 1, a penetration depth of 92% corresponds to a wet rubbing fastness of grade 4-5, while in Comparative Example 4, a penetration depth of 72% corresponds to only grade 3. Sufficient dye penetration ensures a strong bond between the dye and the fiber, which is fundamental to achieving high color fastness.
[0037] 3. A balance needs to be struck between process strength and fiber protection. Example 2 used stronger process parameters, which achieved the best printing effect, but the fiber strength retention rate (93.8%) and hand feel retention rate (91.2%) were relatively low.
Claims
1. A method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation, characterized in that, The method includes: S1, immersing the silk fabric in a pretreatment solution containing 0.5-2 wt% silk fibroin and 0.1-0.5 wt% nano zinc oxide, at a frequency of 40 kHz and a power density of 0.5 W / cm². 2 S2. Apply ultrasonic fields with different parameters to the corresponding areas according to the outline of the preset printing pattern. Specifically, apply ultrasonic fields with parameters of 28kHz and 1.2W / cm² to the edge area of the pattern. 2 The ultrasound was applied to the central area at 100 kHz and 0.3 W / cm². 2 The ultrasound was applied at 45 kHz and 0.8 W / cm² in the transition zone. 2 S3. Apply ultrasonic treatment for 1-3 minutes, according to the cavitation control area determined in step S2. Specifically: use high-viscosity ink (8-12 mPa·s) for the edge area, low-viscosity ink (2-4 mPa·s) for the center area, and medium-viscosity ink (5-7 mPa·s) for the transition area; S4. First, apply the treatment at a frequency of 25 kHz and a power density of 0.6 W / cm². 2 Pre-fixation was performed under ultrasonic assistance, followed by steam fixation at 102-105℃ for 10-20 minutes.
2. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, In step S1, the nano zinc oxide has a particle size of 20-50 nm and its surface is modified with a silane coupling agent.
3. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, In step S2, the ultrasonic treatment time for the edge area of the pattern is 2-3 minutes, for the center area it is 1-1.5 minutes, and for the transition area it is 1.5-2 minutes.
4. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, In step S3, the high-viscosity ink further contains 0.5-1.5 wt% hydroxyethyl cellulose, the low-viscosity ink contains 0.1-0.5 wt% polyvinylpyrrolidone, and the medium-viscosity ink contains 0.3-0.8 wt% sodium alginate. The viscosity of the high-viscosity ink is 8-12 mPa·s, the viscosity of the low-viscosity ink is 2-4 mPa·s, and the viscosity of the medium-viscosity ink is 5-7 mPa·s.
5. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, In step S4, the ultrasonic-assisted pre-fixation time is 3-5 minutes, and the temperature is controlled at 40-50℃.
6. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, In step S2, when an ultrasonic field is applied, the fabric tension is maintained at 2-5 N / cm.
7. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, In step S3, when reactive dye ink is applied, the printing resolution is 600-1200 dpi.
8. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, During the steam fixation process described in step S4, the relative humidity is maintained at 95-100%.
9. The method for controlling gradient bleeding in digital silk printing using ultrasonic cavitation regulation according to claim 1, characterized in that, The method further includes: S5, using a frequency of 35kHz and a power density of 0.4W / cm² after color fixation. 2 The water is washed with ultrasound at a temperature of 40-50℃ for 5-10 minutes.