Printing ink spraying process for 3D glass cover plate

Abstract

The invention discloses an ink spraying process for a 3D glass cover plate, which comprises the following steps: pretreating the 3D glass cover plate, and performing low-frequency pulse activation and high-frequency continuous activation to adjust the surface energy; the method comprises the following steps: preparing spraying ink, obtaining the curvature distribution of the 3D glass cover plate, dividing a spraying surface into different curvature areas to set differential wet film thicknesses, carrying out partitioned spraying by adopting an atomizing spray gun, and sequentially carrying out near-infrared radiation, ultraviolet curing and low-temperature tempering after spraying to obtain a finished product of the 3D glass cover plate. According to the method, the 3D glass cover plate is subjected to cleaning, drying and degassing pretreatment, staged corona activation and contact angle feedback adjustment are matched, a reinforcing filler and a toughening aid are introduced into spraying ink, a curvature partitioned differential spraying process is implemented, near-infrared pre-stabilization and ultraviolet segmented curing tempering are performed, and the 3D glass cover plate is subjected to heat treatment, so that the 3D glass cover plate is obtained. The problems of bubble pinholes, retraction shrinkage cavities and color difference base exposure can be effectively reduced, so that the adhesion reliability, the appearance consistency and the product yield of products are improved.

Description

Ink spraying process for 3D glass cover Technical Field

[0001] This invention relates to the field of ink spraying, and more particularly to an ink spraying process for 3D glass covers. Background Technology

[0002] 3D glass covers refer to covers formed on flat glass substrates through processes such as hot bending, pressing, or precision forming, which have single or composite curved surfaces. Their outlines often include curved transition areas and chamfered edge areas to meet the requirements of end products for appearance curvature, integrated assembly, and tactile experience. They are widely used in mobile phones, tablets, automotive displays, and wearable devices.

[0003] In existing technologies, to achieve decorative patterns, logos, and anti-glare / anti-peeping effects, 3D glass covers often require the formation of ink or graphic layers in designated areas. Ink spraying has become a commonly used film-forming method due to its adaptability to complex curved surfaces, strong pattern design flexibility, and high efficiency. However, due to the uneven curvature distribution of the 3D glass cover surface, as well as the presence of abrupt curvature changes and chamfered structures, the deposition efficiency and wetting and spreading state of ink atomized particles vary in different areas during the spraying process, easily causing problems such as uneven film thickness, dark edges, or color differences. At the same time, trace amounts of moisture, volatile impurities, or micro-gases are easily left on the surface of the 3D glass cover during processing, handling, and cleaning, and these can accumulate in micropores and chamfers, easily forming defects such as pinholes and bubbles after spraying and curing, affecting the product's appearance and yield. In addition, traditional inks also suffer from insufficient adhesion during the spraying process, causing the coating to peel, crack, or even detach during subsequent use, thus affecting the product's lifespan.

[0004] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an ink spraying process for 3D glass cover plates with uniform film thickness and stable adhesion.

[0006] To achieve this objective, the present invention adopts the following technical solution: an ink spraying process for a 3D glass cover plate, comprising the following steps: S1, pre-treating the 3D glass cover plate to be sprayed to remove surface moisture and impurities; S2, placing the 3D glass cover plate into a corona treatment device, sequentially performing low-frequency pulse activation and high-frequency continuous activation on the outer surface of the 3D glass cover plate, after activation the glass surface energy can be adjusted to 48-72mN / m, and allowing it to enter the spraying process within 30s; S3, preparing the spraying ink, wherein the spraying ink comprises: light The composition comprises: 30-55 wt% curing resin, 15-35 wt% solvent, 3-18 wt% coloring agent, 0.05-0.35 wt% leveling and wetting agent, 0.05-0.25 wt% surface tension modifier, 0.15-1.20 wt% reinforcing filler, and 0.07-2.30 wt% toughening agent. The above components are stirred at 300-1200 rpm for 12-35 minutes at 15-30°C, then filtered through a 200-600 mesh filter and allowed to stand for degassing for 10-40 minutes. The apparent viscosity of the ink at a shear rate of 10 s⁻¹ is 120-650 mPa·s, and the apparent viscosity at a shear rate of 1000 s⁻¹ is 12-90 mPa·s; S4, obtain the curvature distribution data of the 3D glass cover plate, divide the spraying surface of the 3D glass cover plate into a central low curvature zone A, a transition medium curvature zone B, and an edge high curvature zone C, and set target wet film thicknesses TA, TB, and TC for the three zones in the spraying control system, satisfying TC > TB > TA, TA being 6-14 μm, and TB being 10 μm. -22μm, TC is 18-35μm; S5, use an atomizing spray gun to spray the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C in sections. The atomizing air pressure of the spray gun is 0.12-0.35MPa, the ink flow rate is 80-220mL / min, and the spray distance is 70-140mm; S6, after spraying, perform near-infrared radiation and ultraviolet curing treatment to make the coating cross-link and cure. Then, perform low-temperature tempering treatment at 50-95℃ for 5-25min to obtain the 3D glass cover plate finished product.

[0007] Using the above technical solution, in step S1, the pretreatment includes: ultrasonically cleaning the 3D glass cover and rinsing it with pure water to remove surface contaminants; then drying it with hot air at 60-110℃ for 6-18 minutes to make the residual moisture on the surface of the 3D glass cover ≤0.08wt%; then placing the dried 3D glass cover in a vacuum degassing chamber and maintaining it under a vacuum of -80 to -96kPa for 3-12 minutes to remove air and volatile organic compounds adsorbed at the micropores and chamfered edges of the 3D glass cover.

[0008] Using the above technical solution, in step S2, the low-frequency pulse frequency of the low-frequency pulse activation treatment is 0.5-5kHz, the duty cycle is 10-35%, and the processing time is 3-15s; the high-frequency frequency of the high-frequency continuous activation treatment is 13.56MHz or 27.12MHz, the power is 200-800W, and the processing time is 8-35s.

[0009] Using the above technical solution, in step S2, after completing low-frequency pulse activation and high-frequency continuous activation, the contact angle of deionized water on the surface of the 3D glass cover is tested by the contact angle measurement module. If the contact angle is greater than 38°, the high-frequency continuous activation power is increased by 50-150W and the processing time is extended by 3-8s; if the contact angle is less than 12°, the high-frequency continuous activation power is reduced by 50-120W and the processing time is shortened by 2-6s, so that the contact angle is maintained at 12-38°.

[0010] Using the above technical solution, in step S5, during the spraying process, the spray gun scans the surface of the 3D glass cover along a preset trajectory, and sets different spraying movement speeds according to the curvature differences of the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C. Specifically, the spraying speed of the central low curvature area A is 300-600 mm / s, the spraying speed of the transition medium curvature area B is 180-350 mm / s, and the spraying speed of the edge high curvature area C is 80-220 mm / s.

[0011] Using the above technical solution, in step S3, the toughening agent includes one or a combination of the following components: HDI trimer, IPDI trimer, or blocked isocyanate; the reinforcing filler is at least one of hexagonal boron nitride nanosheets, montmorillonite nanosheets, or graphene oxide nanosheets that have been surface-grafted with a coupling agent, with a lateral dimension of 80-600 nm and a thickness of 0.8-8 nm; the coupling agent is one of epoxy silane, amino silane, or fluorinated silane, and the grafting amount is 0.5-4.0 wt% of the mass of the reinforcing filler.

[0012] Using the above technical solution, in step S4, the curvature distribution of the 3D glass cover is obtained in the following ways: a) obtain the 3D point cloud of the 3D glass cover by structured light scanning and calculate the principal curvature; b) obtain the height field by laser displacement sensor and convert the curvature level; c) directly read the curvature using CAD model and generate spraying partitions; wherein the curvature partition thresholds satisfy: when the principal curvature radius R ≥ 500mm, it is the central low curvature zone A; when 200mm ≤ R < 500mm, it is the transition medium curvature zone B; when R < 200mm, it is the edge high curvature zone C.

[0013] Using the above technical solution, in step S6, the near-infrared radiation treatment process parameters are: near-infrared band 780-1100nm, irradiation power density 0.35-1.5W / cm², and time 15-80s; the ultraviolet curing treatment process parameters are: ultraviolet wavelength 365-405nm, energy density 700-2200mJ / cm², and time 24-38s. After curing, the dry film thickness of the ink layer is controlled as follows: the central low curvature area A is 4-10μm, the transition medium curvature area B is 7-16μm, and the edge high curvature area C is 12-26μm. The coating pencil hardness is ≥2H and the cross-cut adhesion reaches level 0.

[0014] Using the above technical solution, in step S6, the ultraviolet curing adopts a segmented processing process: the first segment has an ultraviolet energy density of 700-1200 mJ / cm², the second segment has an ultraviolet energy density of 1400-2200 mJ / cm², and a 1-4s interval cooling is set between the two segments to ensure that the temperature rise of the coating surface is ≤35℃.

[0015] Using the above technical solution, in step S3, the photocurable resin system includes at least one or a combination of the following components: acrylate oligomers, polyurethane acrylates, epoxy acrylates, or polyester acrylates; wherein, the number average molecular weight of the photocurable resin system is 800-5000; the solvent system includes one or a combination of the following components: propylene glycol methyl ether acetate, cyclohexanone, ethyl acetate, γ-butyrolactone, or dimethyl carbonate; the coloring component is an organic pigment or an inorganic pigment; the organic pigment includes phthalocyanine blue and phthalocyanine... The inorganic pigments include titanium dioxide, iron oxide, or carbon black, and the coloring components are dispersed before being added to step S3 so that their D90 particle size in the ink is ≤1.5μm; the leveling and wetting agent is at least one of the following substances: polyether modified silicone oil, acrylate leveling agent, or fluorinated surfactant; the surface tension regulator is fluorinated modified acrylate, silicon-containing low molecular weight surface regulator, or a combination thereof, to control the surface tension of the spray ink at 25°C to 22-32mN / m.

[0016] Compared with existing technologies, this invention has the following beneficial effects: By pre-treating the 3D glass cover plate to be coated with ink through cleaning, drying, and degassing, this invention reduces the interference of residual moisture, air, and volatile impurities at micropores and chamfered edges on film formation, thus reducing pinholes, bubbles, and adhesion dispersion from the source. Subsequently, through staged corona activation combined with contact angle feedback adjustment, the surface of the 3D glass cover plate can be stably kept within a suitable range for ink wetting, effectively improving the wetting consistency of curved surfaces and edge areas, and reducing shrinkage, pinholes, and film thickness fluctuations. Adding reinforcing fillers and toughening agents to the spraying ink can improve the wear resistance, crack resistance, and interfacial bonding reliability of the cured coating while ensuring smooth atomization and a delicate appearance. Furthermore, by implementing a differentiated spraying method based on curvature zoning, high-curvature edge areas can achieve compensatory film formation, reducing the risk of edge darkening, color difference banding, and substrate exposure. The use of near-infrared pre-stabilization and UV segmented curing combined with low-temperature tempering can promote solvent release and alleviate curing shrinkage stress, thereby comprehensively improving the uniformity, reliability, and product yield of the 3D glass cover's sprayed appearance. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., described below refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the technical features involved in the various embodiments of the invention can be combined with each other as long as they do not conflict with each other.

[0018] This invention provides an ink spraying process for 3D glass covers, including the following steps: S1, pre-treating the 3D glass cover to be sprayed to remove surface moisture and impurities; by removing surface moisture and impurities through pre-treatment, the cleanliness of the glass surface can be improved, thereby providing a process basis for subsequent spraying and curing processes.

[0019] S2. Place the 3D glass cover plate into the corona treatment device, and sequentially perform low-frequency pulse activation and high-frequency continuous activation on the outer surface of the 3D glass cover plate. After activation, the surface energy of the glass is adjusted to 48-72 mN / m, and it is then put into the spraying process within 30 seconds. In this way, the wetting state of the 3D glass cover plate surface can be adjusted to be within the surface energy range suitable for ink film formation. By performing low-frequency pulse activation first and then high-frequency continuous activation, residual organic contaminants can be removed while the surface energy of the 3D glass cover plate is increased, thereby avoiding the problems of local over-treatment or under-activation caused by single-intensity activation. Controlling the surface energy after activation at 48-72 mN / m can facilitate the stable spreading of ink on the 3D curved surface and edge areas, reducing defects such as shrinkage, pinholes and uneven film thickness. At the same time, entering the spraying process within 30 seconds after activation can prevent the surface energy from decaying over time and affecting the wetting and adhesion effects, thereby ensuring the stability and consistency of the spraying process.

[0020] S3. Prepare the spraying ink, which comprises: 30-55 wt% UV-curable resin system, 15-35 wt% solvent system, 3-18 wt% coloring component, 0.05-0.35 wt% leveling and wetting agent, 0.05-0.25 wt% surface tension modifier, 0.15-1.20 wt% reinforcing filler, and 0.07-2.30 wt% toughening agent; stir the above components at 300-1200 rpm for 12-35 min at 15-30℃, then filter through a 200-600 mesh filter and allow to stand for degassing for 10-40 min, so that the apparent viscosity of the ink at a shear rate of 10 s⁻¹ is 120-650 mPa·s. The apparent viscosity at 1000s⁻¹ is 12-90 mPa·s; the UV-curable resin system provides the main structure and hardness basis of the cured coating, while the solvent system is used to adjust the ink viscosity and control the evaporation rate, so that the atomized particles can form a continuous wet film when they reach the curved surface, without causing pinholes due to evaporation imbalance; the coloring component can ensure the consistency of masking and appearance, and together with the leveling wetting agent and surface tension regulator, the surface tension and wetting effect of the ink can be stabilized within a suitable range, so that the ink can be evenly spread in the curvature variation area and reduce pinholes and shrinkage; the reinforcing filler and toughening agent can improve the wear resistance, crack resistance and adhesion reliability of the cured film, and prevent the coating from becoming brittle or peeling off at the edges under subsequent stress. It should be noted that under low shear rate conditions, the ink is in a static or slowly flowing state. Maintaining a relatively high apparent viscosity of 120-650 mPa·s at this time helps to suppress the sedimentation of pigments and fillers, and reduce the sagging or accumulation of the wet film on 3D curved surfaces, especially at the edges and inclined areas, thus ensuring the stability of the film thickness. During the spraying process, the ink experiences a high shear rate of 1000 s⁻¹ inside the spray gun and during the atomization stage. At this time, controlling the apparent viscosity at 12-90 mPa·s can effectively reduce flow resistance, making the ink easier to atomize and form uniform and fine droplets, thereby improving the coverage of curved surfaces and chamfered areas. By creating significant viscosity differences under different shear conditions, the ink can have good shear thinning characteristics, which not only ensures the smoothness and uniformity of the spraying process, but also avoids appearance defects caused by excessively low viscosity during the film formation stage, thereby improving the consistency and reliability of 3D glass cover spraying.

[0021] S4. Obtain the curvature distribution data of the 3D glass cover plate, divide the spraying surface of the 3D glass cover plate into a central low curvature area A, a transition medium curvature area B, and an edge high curvature area C. In the spraying control system, set target wet film thicknesses TA, TB, and TC for the three areas respectively, satisfying TC > TB > TA, with TA being 6-14μm, TB being 10-22μm, and TC being 18-35μm. The central low curvature area is closer to a plane, making it easier for the ink to spread evenly and form a stable wet film. Excessive thickness will lead to increased curing shrinkage stress and a dull appearance. The edge high curvature area and the chamfered transition area are due to... The presence of abrupt curvature reduces the effective droplet arrival rate, and the wet film is more prone to local thinning, exposure of the substrate, or edge retraction under the influence of gravity and surface tension. Therefore, the coating surface is divided into regions A, B, and C, and the wet film thickness is set to satisfy TC > TB > TA. This is equivalent to compensatory film formation for different curvature regions: the target wet film thickness is increased in the high curvature region at the edge to offset insufficient deposition and the tendency of edge thinning; a lower thickness is controlled in the central region to ensure visual transparency; and an intermediate thickness is used in the transition region to achieve a smooth thickness transition, thereby reducing the color difference band caused by abrupt film thickness changes and improving the overall appearance consistency.

[0022] S5. Use an atomizing spray gun to spray the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C in sections. The atomizing air pressure of the spray gun is 0.12-0.35MPa, the ink flow rate is 80-220mL / min, and the spray distance is 70-140mm. In this way, relatively stable atomization and deposition conditions can be maintained in different curvature areas, so that the ink can uniformly cover the curved surface and form a continuous wet film, and it is not easy to produce fog, drips, and film thickness fluctuations, thereby improving the consistency of the 3D glass cover spraying appearance.

[0023] S6. After spraying, near-infrared radiation and ultraviolet curing are performed to cross-link and cure the coating. Then, a low-temperature tempering treatment at 50-95℃ for 5-25 minutes is applied to obtain the finished 3D glass cover. Near-infrared radiation provides rapid and gentle energy input to the wet film, allowing it to reach a stable state more quickly in curved and edge areas, thus reducing appearance defects such as sagging, edge stacking, and film thickness shrinkage caused by flow. Subsequent ultraviolet curing completes cross-linking and network formation in a short time, creating a dense coating while maintaining the appearance, improving hardness and adhesion. The subsequent low-temperature tempering treatment at 50-95℃ after curing promotes further release of residual solvents and alleviates internal stress caused by curing shrinkage, thereby improving the structural stability and interfacial bonding reliability of the coating.

[0024] Furthermore, in step S1, the pretreatment includes: ultrasonically cleaning the 3D glass cover and rinsing it with pure water to remove surface contaminants; then drying it with hot air at 60-110℃ for 6-18 minutes to ensure that the residual moisture on the surface of the 3D glass cover is ≤0.08wt%; then placing the dried 3D glass cover in a vacuum degassing chamber and maintaining it under a vacuum of -80 to -96kPa for 3-12 minutes to remove air and volatile organic compounds adsorbed at the micropores and chamfered edges of the 3D glass cover. Ultrasonic cleaning combined with pure water rinsing effectively removes and carries away microparticles and oily impurities, providing a clean interface for subsequent film formation. Hot air drying at 60-110℃, with residual moisture controlled below 0.08wt%, reduces moisture content and minimizes defects caused by moisture loss during curing. Finally, degassing under a vacuum of -80 to -96 kPa for a certain period releases air and volatile organic compounds that are difficult to expel from micropores and chamfered edges, reducing the risk of gas release and bubbling during spraying or curing, thereby improving the yield and interface bonding stability of 3D curved surface spraying.

[0025] Furthermore, in step S2, the low-frequency pulse frequency of the low-frequency pulse activation treatment is 0.5-5kHz, the duty cycle is 10-35%, and the processing time is 3-15s; the high-frequency frequency of the high-frequency continuous activation treatment is 13.56MHz or 27.12MHz, the power is 200-800W, and the processing time is 8-35s. Low-frequency pulses, operating at 0.5-5kHz with a duty cycle of 10-35%, intermittently input energy, resulting in a periodic discharge. This approach effectively activates residual organic contaminants and difficult-to-treat areas while avoiding over-treatment, excessive surface energy, or heat accumulation caused by continuous high-frequency discharges, thus improving the stability of the activation process. High-frequency continuous activation at 13.56MHz or 27.12MHz provides more uniform and continuous energy input within a power range of 200-800W and a time range of 8-35s. This allows for more complete introduction of polar groups onto the glass surface, more stable surface energy enhancement, and improved surface energy consistency in curved and chamfered areas, thereby providing suitable interface conditions for subsequent ink wetting, spreading, and adhesion.

[0026] Furthermore, in step S2, after completing low-frequency pulse activation and high-frequency continuous activation, the contact angle of deionized water on the surface of the 3D glass cover is tested by the contact angle measurement module. If the contact angle is greater than 38°, the high-frequency continuous activation power is increased by 50-150W and the processing time is extended by 3-8s; if the contact angle is less than 12°, the high-frequency continuous activation power is reduced by 50-120W and the processing time is shortened by 2-6s, so that the contact angle is maintained at 12-38°. The contact angle of deionized water reflects the polarity and surface energy level of the glass surface. A large contact angle indicates insufficient activation and a limited number of polar groups on the surface. This makes it difficult for the ink to fully wet the surface during spraying, easily leading to problems such as shrinkage, pinholes, or insufficient adhesion. In this case, increasing the high-frequency continuous activation power and appropriately extending the processing time can remove residual organic matter and introduce polar groups, raising the surface energy to a range conducive to film formation. Conversely, if the contact angle is too small, it indicates excessive surface activation and excessively high surface energy. This results in excessively fast ink spreading, which can easily cause backflow, accumulation, or local imbalance in curved and edge areas, thus affecting film thickness and appearance consistency.

[0027] Furthermore, in step S5, during the spraying process, the spray gun scans the surface of the 3D glass cover along a preset trajectory, and sets different spraying movement speeds according to the curvature differences of the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C. Specifically, the spraying speed of the central low curvature area A is 300-600 mm / s, the spraying speed of the transition medium curvature area B is 180-350 mm / s, and the spraying speed of the edge high curvature area C is 80-220 mm / s. The central low-curvature area is closer to a flat surface, resulting in a high droplet arrival rate and easier uniform wet film spreading. If the speed is too low, it will lead to excessive ink supply per unit area, increasing the risk of sagging, accumulation, or curing stress. In the transition curvature area, there are curvature changes, and the effective droplet deposition rate begins to decrease. At the same time, the wet film is more prone to thickness fluctuations, requiring an appropriate reduction in speed to increase coverage and uniformity. In the high-curvature area at the edge and near the chamfer, there are abrupt curvature changes. The effective droplet arrival rate is lowest in this area, and the wet film is more likely to thin or shrink under the action of surface tension. Therefore, reducing the speed to prolong the residence time will increase the effective ink supply per unit area and reduce the probability of edge exposure, insufficient film thickness, and color difference banding.

[0028] Further, in step S3, the toughening agent includes one or a combination of the following components: HDI trimer, IPDI trimer, or blocked isocyanate; the reinforcing filler is at least one of hexagonal boron nitride nanosheets, montmorillonite nanosheets, or graphene oxide nanosheets that have been surface-grafted with a coupling agent, with a lateral dimension of 80-600 nm and a thickness of 0.8-8 nm; the coupling agent is one of epoxy silane, amino silane, or fluorinated silane, with a grafting amount of 0.5-4.0 wt% of the reinforcing filler mass. Adding toughening agents such as HDI trimer, IPDI trimer, or blocked isocyanates to the ink allows the coating to maintain a certain level of hardness and wear resistance while possessing better flexibility and impact resistance. This makes the coating less prone to cracking or peeling when subjected to assembly friction or temperature changes on the edges and curved areas of the 3D glass cover. Using sheet-like reinforcing fillers such as hexagonal boron nitride, montmorillonite, or graphene oxide can disperse external stress and prevent rapid crack propagation, thereby improving the wear resistance and crack resistance of the coating. However, if these sheet-like materials are directly added to the ink, they are prone to clumping and uneven dispersion, which can negatively impact the appearance and spraying stability. Therefore, surface treatment with silane coupling agents is used to make the fillers easier to be coated by the resin and evenly dispersed in the ink. By controlling the grafting amount within an appropriate range, the coating can play a reinforcing and toughening role without affecting the spraying and appearance, thereby improving the overall reliability of the 3D glass cover coating.

[0029] Furthermore, in step S4, the curvature distribution of the 3D glass cover is obtained in the following ways: a) obtain the 3D point cloud of the 3D glass cover by structured light scanning and calculate the principal curvature; b) obtain the height field by laser displacement sensor and convert the curvature level; c) directly read the curvature using the CAD model and generate the spraying partition; wherein the curvature partition threshold satisfies: when the principal curvature radius R ≥ 500 mm, it is the central low curvature zone A; when 200 mm ≤ R < 500 mm, it is the transition medium curvature zone B; when R < 200 mm, it is the edge high curvature zone C. By using structured light scanning, laser displacement measurement, and curvature information obtained from CAD models, the curvature distribution of the cover plate surface can be accurately obtained under different production conditions. Based on this, spraying zones can be generated. The area with a main curvature radius R ≥ 500 mm is defined as the central low curvature zone, the area with R between 200-500 mm is defined as the transition medium curvature zone, and the area with R < 200 mm is defined as the edge high curvature zone. This is based on the obvious boundary characteristics of the spraying deposition behavior as curvature changes, thus providing a basis for setting film thickness and spraying parameters for subsequent zones, improving the controllability and repeatability of the spraying process.

[0030] Furthermore, in step S6, the near-infrared radiation treatment process parameters are: near-infrared band 780-1100nm, irradiation power density 0.35-1.5W / cm², and time 15-80s; the ultraviolet curing treatment process parameters are: ultraviolet wavelength 365-405nm, energy density 700-2200mJ / cm², and time 24-38s. After curing, the dry film thickness of the ink layer is controlled as follows: the central low curvature area A is 4-10μm, the transition medium curvature area B is 7-16μm, and the edge high curvature area C is 12-26μm. The coating pencil hardness is ≥2H and the cross-cut adhesion reaches level 0.

[0031] Furthermore, in step S6, the UV curing adopts a segmented processing technology: the first segment has a UV energy density of 700-1200 mJ / cm², the second segment has a UV energy density of 1400-2200 mJ / cm², and a 1-4s interval cooling is set between the two segments to ensure that the temperature rise of the coating surface is ≤35℃. The first stage uses a lower energy density to quickly initiate the polymerization reaction, allowing the wet film to achieve a certain strength while maintaining its intended appearance. This avoids excessive surface crusting caused by a single high-energy irradiation, leaving unreacted components inside. The second stage uses a higher energy density to improve the degree of crosslinking and curing depth, ensuring that the final hardness, abrasion resistance, and chemical resistance of the coating meet the standards. Since UV curing itself is exothermic, and local heat accumulation is more likely to occur at the edges of 3D glass and in thick film areas, excessive temperature rise can lead to increased curing shrinkage, increased interfacial stress, and even adhesion fluctuations or the risk of microcracks. Therefore, a 1-4 second cooling interval is set between the two stages, and the surface temperature rise is controlled at ≤35℃. This allows heat to be released in time, making the curing process more stable, thereby improving the coating curing quality and the stability of the interfacial bonding.

[0032] Further, in step S3, the photocurable resin system includes at least one or a combination of the following components: acrylate oligomers, polyurethane acrylates, epoxy acrylates, or polyester acrylates; wherein the number average molecular weight of the photocurable resin system is 800-5000; the solvent system includes one or a combination of the following components: propylene glycol methyl ether acetate, cyclohexanone, ethyl acetate, γ-butyrolactone, or dimethyl carbonate; the coloring component is an organic pigment or an inorganic pigment; the organic pigment includes phthalocyanine blue, phthalocyanine green, etc. The inorganic pigments include titanium dioxide, iron oxide, or carbon black, and the coloring components are dispersed before being added to step S3 so that their D90 particle size in the ink is ≤1.5μm; the leveling and wetting agent is at least one of the following: polyether-modified silicone oil, acrylate leveling agent, or fluorinated surfactant; the surface tension modifier is fluorinated modified acrylate, silicon-containing low molecular weight surface modifier, or a combination thereof, to control the surface tension of the spray ink at 25°C to 22-32mN / m. The selection of acrylic oligomers, polyurethane acrylates, epoxy acrylates, or polyester acrylates as the UV-curing resin system, with a number-average molecular weight controlled between 800-5000, aims to achieve a balance between spray application properties and post-curing performance. Too low a molecular weight results in a brittle cured film with insufficient abrasion and chemical resistance, while too high a molecular weight leads to excessive viscosity, difficulty in atomization, and negative impacts on the 3D curved surface spreading effect. Common solvents such as propylene glycol methyl ether acetate, cyclohexanone, ethyl acetate, γ-butyrolactone, or dimethyl carbonate, or their blends, are used as the solvent system to adjust the evaporation rate and solubility, ensuring that the ink maintains an appropriate wetting and leveling time after being sprayed onto the 3D curved surface. It avoids orange peel effect due to excessively rapid evaporation or sagging due to excessively slow evaporation; the coloring components are limited to typical organic or inorganic pigments, and the D90 after pre-dispersion is required to be ≤1.5μm. This is to reduce the risk of graininess, gun clogging, and color spots while ensuring masking and color stability, thereby improving the consistency of appearance; the leveling and wetting agent uses polyether modified silicone oil, acrylate leveling agent, or fluorinated surfactant to improve surface wetting and inhibit pinholes and shrinkage; at the same time, the surface tension of the ink at 25℃ is controlled at 22-32mN / m by fluorinated modified acrylate or silicon-containing low molecular weight surface conditioner, so that the ink has a stable spreading and film-forming effect in different curvature areas of 3D glass.

[0033] Example 1Embodiment 1 of the present invention provides an ink spraying process for a 3D glass cover plate, comprising the following steps: S1, pre-treating the 3D glass cover plate to be sprayed to remove surface moisture and impurities; the pre-treatment includes: ultrasonic cleaning of the 3D glass cover plate and rinsing with pure water to remove surface contaminants; then drying with hot air at 60°C for 18 minutes to ensure that the residual moisture on the surface of the 3D glass cover plate is ≤0.08wt%; then placing the dried 3D glass cover plate in a vacuum degassing chamber and maintaining it under a vacuum of -96kPa for 12 minutes to remove air and volatile organic compounds adsorbed at the micropores and chamfered edges of the 3D glass cover plate; S2, placing the 3D glass cover plate into... In the corona treatment device, the outer surface of the 3D glass cover is sequentially subjected to low-frequency pulse activation and high-frequency continuous activation. The low-frequency pulse activation treatment has a low-frequency pulse frequency of 5kHz, a duty cycle of 25%, and a processing time of 10s; the high-frequency continuous activation treatment has a high-frequency frequency of 27.12MHz, a power of 400W, and a processing time of 26s. After activation, the glass surface energy can be adjusted to 56mN / m, allowing it to enter the spraying process within 30s. After completing the low-frequency pulse activation and high-frequency continuous activation, the deionized water contact angle on the surface of the 3D glass cover is tested using a contact angle measurement module. If the contact angle is greater than 38°, the high-frequency continuous activation power is increased by 100W and the treatment time is extended. If the contact angle is less than 12°, reduce the high-frequency continuous activation power by 60W and shorten the treatment time by 4 seconds to maintain the contact angle at 36°; S3, prepare the spraying ink, which includes: 45.9 wt% UV-curable resin system, 35 wt% solvent system, 15 wt% coloring component, 0.35 wt% leveling and wetting agent, 0.25 wt% surface tension regulator, 1.20 wt% reinforcing filler, and 2.30 wt% toughening agent; stir the above components at 800 rpm for 25 min at 25°C, then filter through a 400-mesh filter and let stand for degassing for 20 min, so that the apparent viscosity of the ink at a shear rate of 10 s⁻¹ is 450 mPa·s. The apparent viscosity at a shear rate of 1000 s⁻¹ is 80 mPa·s; wherein the toughening agent is HDI trimer; the reinforcing filler is hexagonal boron nitride nanosheets grafted with a coupling agent, with a lateral dimension of 200 nm and a thickness of 2 nm; the coupling agent is epoxy silane, and the grafting amount is 2 wt% of the reinforcing filler mass; the photocurable resin system is an acrylate oligomer; the solvent system is propylene glycol methyl ether acetate; the coloring component is an organic pigment or an inorganic pigment; the organic pigment is phthalocyanine blue; the inorganic pigment is titanium dioxide, and the coloring component is dispersed before being added in step S3 to ensure that its D90 particle size in the ink is ≤1.5μm; the leveling and wetting agent is polyether-modified silicone oil; the surface tension regulator is fluorine-modified acrylate to control the surface tension of the sprayed ink at 25℃ to 24mN / m; S4, obtain the curvature distribution data of the 3D glass cover plate, specifically: a, obtain the three-dimensional point cloud of the 3D glass cover plate by structured light scanning and calculate the principal curvature; b, obtain the height field by laser displacement sensor and convert the curvature level; c, directly read the curvature using the CAD model and generate the spraying partition; divide the spraying surface of the 3D glass cover plate into a central low curvature area A, a transition medium curvature area B, and an edge high curvature area C, wherein the curvature partition threshold satisfies: when the principal curvature radius The central low curvature zone A is defined as R ≥ 500 mm; the transition medium curvature zone B is defined as 200 mm ≤ R < 500 mm; and the edge high curvature zone C is defined as R < 200 mm. Target wet film thicknesses TA, TB, and TC are set for each of the three zones in the spraying control system, satisfying TC > TB > TA, with TA being 12 μm, TB being 18 μm, and TC being 28 μm. S5. An atomizing spray gun is used to spray the central low curvature zone A, the transition medium curvature zone B, and the edge high curvature zone C in sections. The atomizing air pressure of the spray gun is 0.35 MPa, the ink flow rate is 110 mL / min, and the spray distance is 120 mm. During the spraying process, the spray gun follows a preset trajectory to spray the three zones. The surface of the glass cover was scanned, and different spraying speeds were set according to the curvature differences of the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C. Specifically, the spraying speed for the central low curvature area A was 400 mm / s, the spraying speed for the transition medium curvature area B was 320 mm / s, and the spraying speed for the edge high curvature area C was 210 mm / s. S6. After spraying, near-infrared radiation and ultraviolet curing were performed to complete the cross-linking and curing of the coating. Subsequently, it was subjected to a low-temperature tempering treatment at 85℃ for 10 minutes to obtain the finished 3D glass cover. The near-infrared radiation treatment process parameters were: near-infrared band 980 nm, irradiation power... The UV curing process parameters are: UV wavelength 405nm, energy density 2000mJ / cm², and time 30s. After curing, the dry film thickness of the ink layer is controlled as follows: 6μm in the central low-curvature zone A, 8μm in the transition medium-curvature zone B, and 12μm in the edge high-curvature zone C. The coating's pencil hardness is ≥2H, and its cross-cut adhesion reaches level 0. The UV curing process employs a segmented approach: the first segment has a UV energy density of 1200mJ / cm², and the second segment has a UV energy density of 2000mJ / cm², with a 2s cooling interval between the two segments to ensure the coating surface temperature rise is ≤35℃.

[0034] Example 2Embodiment 2 of the present invention provides an ink spraying process for a 3D glass cover plate, comprising the following steps: S1, pre-treating the 3D glass cover plate to be sprayed to remove surface moisture and impurities; the pre-treatment includes: ultrasonically cleaning the 3D glass cover plate and rinsing it with pure water to remove surface contaminants; then drying it with hot air at 90°C for 10 minutes to make the residual moisture on the surface of the 3D glass cover plate ≤0.08wt%; then placing the dried 3D glass cover plate in a vacuum degassing chamber and maintaining it under a vacuum of -80kPa for 10 minutes to remove air and volatile organic compounds adsorbed at the micropores and chamfered edges of the 3D glass cover plate; S2, placing the 3D glass cover plate... The 3D glass cover was placed in a corona treatment device, where its outer surface underwent sequential low-frequency pulse activation and high-frequency continuous activation. The low-frequency pulse activation had a pulse frequency of 4kHz, a duty cycle of 20%, and a processing time of 12s. The high-frequency continuous activation had a high frequency of 13.56MHz, a power of 600W, and a processing time of 20s. After activation, the glass surface energy was adjusted to 52mN / m, allowing it to proceed to the spraying process within 30s. After both low-frequency pulse activation and high-frequency continuous activation, the deionized water contact angle on the 3D glass cover surface was tested using a contact angle measurement module. If the contact angle was greater than 38°, the high-frequency continuous activation power was increased by 120W. Extend the treatment time by 4 seconds; if the contact angle is less than 12°, reduce the high-frequency continuous activation power by 70W and shorten the treatment time by 4 seconds to maintain the contact angle at 34°; S3, prepare the spraying ink, which includes: 49.85wt% UV-curable resin system, 32wt% solvent system, 16wt% coloring component, 0.35wt% leveling and wetting agent, 0.25wt% surface tension regulator, 0.15wt% reinforcing filler, and 1.4wt% toughening agent; stir the above components at 1000rpm for 24min at 26°C, then filter through a 200-mesh filter and let stand for degassing for 40min to make the apparent viscosity of the ink at a shear rate of 10s⁻¹ 400 mmol / L. The apparent viscosity at a shear rate of 1000 s⁻¹ is 50 mPa·s; wherein the toughening agent is IPDI trimer; the reinforcing filler is hexagonal boron nitride nanosheets grafted with a coupling agent, with a lateral dimension of 100 nm and a thickness of 2 nm; the coupling agent is aminosilane, and the grafting amount is 3 wt% of the reinforcing filler mass; the photocurable resin system is polyurethane acrylate; the solvent system is cyclohexanone; the coloring component is an organic pigment or an inorganic pigment; the organic pigment is phthalocyanine green; the inorganic pigment is carbon black, and the coloring component is dispersed before being added in step S3 so that its D90 particle size in the ink is ≤1.5μm; the leveling and wetting agent is a fluorinated surfactant; the surface tension regulator is a fluorinated modified acrylate to control the surface tension of the sprayed ink at 25℃ to 24mN / m; S4, obtain the curvature distribution data of the 3D glass cover plate, specifically: a, obtain the three-dimensional point cloud of the 3D glass cover plate by structured light scanning and calculate the principal curvature; b, obtain the height field by laser displacement sensor and convert the curvature level; c, directly read the curvature using the CAD model and generate the spraying partition; divide the spraying surface of the 3D glass cover plate into a central low curvature area A, a transition medium curvature area B, and an edge high curvature area C, wherein the curvature partition threshold satisfies: when the principal curvature radius The central low curvature zone A is defined as R ≥ 500 mm; the transition medium curvature zone B is defined as 200 mm ≤ R < 500 mm; and the edge high curvature zone C is defined as R < 200 mm. Target wet film thicknesses TA, TB, and TC are set for each of the three zones in the spraying control system, satisfying TC > TB > TA, with TA being 10 μm, TB being 16 μm, and TC being 30 μm. S5. An atomizing spray gun is used to spray the central low curvature zone A, the transition medium curvature zone B, and the edge high curvature zone C in sections. The atomizing air pressure of the spray gun is 0.35 MPa, the ink flow rate is 110 mL / min, and the spray distance is 90 mm. During the spraying process, the spray gun follows a preset trajectory to spray the 3D glass... The surface of the glass cover is scanned, and different spraying speeds are set according to the curvature differences of the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C. Specifically, the spraying speed for the central low curvature area A is 500 mm / s, the spraying speed for the transition medium curvature area B is 320 mm / s, and the spraying speed for the edge high curvature area C is 210 mm / s. S6. After spraying, near-infrared radiation and ultraviolet curing treatments are performed to complete the cross-linking and curing of the coating. Subsequently, it undergoes a low-temperature tempering treatment at 80℃ for 12 minutes to obtain the finished 3D glass cover. The near-infrared radiation treatment process parameters are: near-infrared band 1100 nm, irradiation power density... The UV curing process parameters are: UV wavelength 405nm, energy density 2200mJ / cm², and time 38s. After curing, the dry film thickness of the ink layer is controlled as follows: 10μm in the central low-curvature zone A, 14μm in the transition medium-curvature zone B, and 26μm in the edge high-curvature zone C. The coating's pencil hardness is ≥2H, and its cross-cut adhesion reaches level 0. The UV curing process employs a segmented approach: the first segment has a UV energy density of 1200mJ / cm², and the second segment has a UV energy density of 2200mJ / cm², with a 3s cooling interval between the two segments to ensure the coating surface temperature rise is ≤35℃.

[0035] Comparative Example 1The difference between the ink spraying process of the 3D glass cover plate in Comparative Example 1 and Example 1 is that in step S1, only ultrasonic cleaning, pure water rinsing and hot air drying are performed on the 3D glass cover plate, and vacuum degassing is not performed. The remaining steps and parameters are the same as in Example 1.

[0036] Comparative Example 2 The difference between the ink spraying process of the 3D glass cover plate in Comparative Example 2 and Example 1 is that in step S2, only a single high-frequency continuous corona activation treatment is used, and low-frequency pulse activation is not performed. The other conditions are the same as in Example 1.

[0037] Comparative Example 3 The difference between the ink spraying process of the 3D glass cover plate in Comparative Example 3 and Example 1 is that in step S2, after corona activation, no contact angle test and subsequent power adjustment are performed, and the remaining steps are the same as in Example 1.

[0038] Comparative Example 4 The difference between the ink spraying process of the 3D glass cover plate in Comparative Example 4 and Example 1 is that in step S3, the sprayed ink does not contain reinforcing fillers, while the remaining ink components and process parameters are the same as in Example 1.

[0039] Comparative Example 5 The difference between the ink spraying process of the 3D glass cover plate in Comparative Example 5 and Example 1 is that: in step S4, the curvature zoning treatment of the 3D glass cover plate is not performed, and the entire spraying surface adopts a uniform target wet film thickness. The remaining steps are the same as in Example 1.

[0040] Comparative Example 6 The difference between the ink spraying process of the 3D glass cover plate in Comparative Example 6 and Example 1 is that in step S6, only a single ultraviolet curing treatment is used, without near-infrared radiation pretreatment and low-temperature tempering, and the other parameters are the same as in Example 1.

[0041] The 3D glass covers prepared in Examples 1-2 and Comparative Examples 1-6 were subjected to quality tests to verify or understand their performance. The results are shown in Table 1.

[0042] Table 1. Comparison of 3D Glass Cover Performance Tests. The comparison between Example 1 and Comparative Example 1 shows that pre-treating the 3D glass cover before spraying and introducing a degassing process effectively reduces defects such as pinholes and bubbles caused by residual gases or volatiles during spraying and curing, compared to simply cleaning and drying without degassing. This improves the uniformity of the coating appearance and the yield of the finished product. The comparison between Example 1 and Comparative Example 2 shows that using a combination of low-frequency pulse activation and high-frequency continuous activation, compared to single continuous activation, results in more balanced activation and stable wetting of the 3D glass cover surface, reducing uneven appearance, color difference, and adhesion fluctuations caused by wetting imbalance in curved surfaces and edge areas. The comparison between Example 1 and Comparative Example 3 shows that introducing contact angle detection and power feedback adjustment after corona activation is more conducive to maintaining a stable glass surface, thereby improving the spraying effect and reducing appearance defects and poor adhesion. The comparison between Example 1 and Comparative Example 4 shows that adding surface-treated reinforcing fillers to the spraying ink can improve the structural stability and damage resistance of the cured coating compared to spraying without reinforcing fillers, thereby improving the overall reliability of the coating. The comparison between Example 1 and Comparative Example 5 shows that by obtaining the curvature distribution of the 3D glass cover plate and controlling it in zones, and implementing differentiated film-forming spraying in different curvature areas, compared to the method of no zones and uniform wet film thickness, it can effectively improve the film thickness and appearance consistency in high curvature areas at the edges, reduce problems such as edge darkening, color difference bands and film thickness fluctuations, thereby improving the overall spraying uniformity. In addition, the comparison results between Example 1 and Comparative Example 6 show that the synergistic treatment of near-infrared radiation and ultraviolet curing, combined with the subsequent tempering process, can make the curing process more stable and the coating morphology more stable compared to the method of only performing single ultraviolet curing treatment, thereby improving the coating's resistance and adhesion stability under conditions such as thermal shock.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ink spraying process for 3D glass covers, characterized in that, Includes the following steps: S1. Pre-treat the 3D glass cover plate to be sprayed to remove surface moisture and impurities; S2. Place the 3D glass cover plate in a corona treatment device, and sequentially perform low-frequency pulse activation and high-frequency continuous activation on the outer surface of the 3D glass cover plate. After activation, the glass surface energy can be adjusted to 48-72 mN / m, and it should enter the spraying process within 30 seconds; S3. Prepare the spraying ink, which includes: 30-55 wt% UV-curable resin system, 15-35 wt% solvent system, and coloring group. The ink is composed of 3-18 wt% leveling and wetting agent, 0.05-0.35 wt% surface tension modifier, 0.05-0.25 wt% reinforcing filler, 0.15-1.20 wt% toughening agent, and 0.07-2.30 wt% toughening agent. The above components are stirred at 300-1200 rpm for 12-35 min at 15-30℃, then filtered through a 200-600 mesh filter and allowed to stand for degassing for 10-40 min, so that the apparent viscosity of the ink at a shear rate of 10 s⁻¹ is 1. The apparent viscosity at a shear rate of 1000 s⁻¹ is 12-90 mPa·s, ranging from 20-650 mPa·s. S4: Obtain the curvature distribution data of the 3D glass cover plate, divide the sprayed surface of the 3D glass cover plate into a central low-curvature region A, a transitional medium-curvature region B, and an edge high-curvature region C. In the spraying control system, set target wet film thicknesses TA, TB, and TC for each of the three regions, satisfying TC > TB > TA, with TA being 6-14 μm, TB being 10-22 μm, and TC being 1... 8-35μm; S5, use an atomizing spray gun to spray the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C in sections. The atomizing air pressure of the spray gun is 0.12-0.35MPa, the ink flow rate is 80-220mL / min, and the spray distance is 70-140mm; S6, after spraying, perform near-infrared radiation and ultraviolet curing treatment to complete the cross-linking and curing of the coating. Then, perform low-temperature tempering treatment at 50-95℃ for 5-25min to obtain the 3D glass cover plate finished product.

2. The ink spraying process for the 3D glass cover plate according to claim 1, characterized in that, In step S1, the pretreatment includes: ultrasonically cleaning the 3D glass cover and rinsing it with pure water to remove surface contaminants; then drying it with hot air at 60-110℃ for 6-18 minutes to ensure that the residual moisture on the surface of the 3D glass cover is ≤0.08wt%; then placing the dried 3D glass cover in a vacuum degassing chamber and maintaining it under a vacuum of -80 to -96kPa for 3-12 minutes to remove air and volatile organic compounds adsorbed in the micropores and chamfered edges of the 3D glass cover.

3. The ink spraying process for the 3D glass cover plate according to claim 1, characterized in that, In step S2, the low-frequency pulse frequency of the low-frequency pulse activation treatment is 0.5-5kHz, the duty cycle is 10-35%, and the processing time is 3-15s; the high-frequency continuous activation treatment has a high frequency of 13.56MHz or 27.12MHz, a power of 200-800W, and a processing time of 8-35s.

4. The ink spraying process for the 3D glass cover plate according to claim 1, characterized in that, In step S2, after completing low-frequency pulse activation and high-frequency continuous activation, the contact angle of deionized water on the surface of the 3D glass cover is tested by the contact angle measurement module. If the contact angle is greater than 38°, the high-frequency continuous activation power is increased by 50-150W and the processing time is extended by 3-8s; if the contact angle is less than 12°, the high-frequency continuous activation power is reduced by 50-120W and the processing time is shortened by 2-6s, so that the contact angle is maintained at 12-38°.

5. The ink spraying process for the 3D glass cover plate according to claim 1, characterized in that, In step S5, during the spraying process, the spray gun scans the surface of the 3D glass cover along a preset trajectory, and sets different spraying movement speeds according to the curvature differences of the central low curvature area A, the transition medium curvature area B, and the edge high curvature area C. Specifically, the spraying speed of the central low curvature area A is 300-600 mm / s, the spraying speed of the transition medium curvature area B is 180-350 mm / s, and the spraying speed of the edge high curvature area C is 80-220 mm / s.

6. The ink spraying process for the 3D glass cover plate according to claim 4, characterized in that, In step S3, the toughening agent comprises one or a combination of the following components: HDI trimer, IPDI trimer, or blocked isocyanate; the reinforcing filler is at least one of hexagonal boron nitride nanosheets, montmorillonite nanosheets, or graphene oxide nanosheets that have been surface-grafted with a coupling agent, having a transverse dimension of 80-600 nm and a thickness of 0.8-8 nm; the coupling agent is one of epoxy silane, amino silane, or fluorinated silane, with a grafting amount of 0.5-4.0 wt% of the reinforcing filler mass.

7. The ink spraying process for the 3D glass cover plate according to claim 1, characterized in that, In step S4, the curvature distribution of the 3D glass cover is obtained in the following ways: a) obtain the 3D point cloud of the 3D glass cover by structured light scanning and calculate the principal curvature; b) obtain the height field by laser displacement sensor and convert the curvature level; c) directly read the curvature using CAD model and generate spraying partitions. The curvature partitioning thresholds satisfy the following conditions: when the main curvature radius R ≥ 500 mm, it is the central low curvature zone A; when 200 mm ≤ R < 500 mm, it is the transitional medium curvature zone B; and when R < 200 mm, it is the edge high curvature zone C.

8. The ink spraying process for the 3D glass cover plate according to claim 1, characterized in that, In step S6, the near-infrared radiation treatment process parameters are: near-infrared band 780-1100nm, irradiation power density 0.35-1.5W / cm², and time 15-80s; the ultraviolet curing treatment process parameters are: ultraviolet wavelength 365-405nm, energy density 700-2200mJ / cm², and time 24-38s. After curing, the dry film thickness of the ink layer is controlled as follows: the central low curvature area A is 4-10μm, the transition medium curvature area B is 7-16μm, and the edge high curvature area C is 12-26μm. The coating pencil hardness is ≥2H and the cross-cut adhesion reaches level 0.

9. The ink spraying process for the 3D glass cover plate according to claim 8, characterized in that, In step S6, the UV curing adopts a segmented process: the UV energy density of the first segment is 700-1200mJ / cm², the UV energy density of the second segment is 1400-2200mJ / cm², and a cooling interval of 1-4s is set between the two segments to ensure that the temperature rise of the coating surface is ≤35℃.

10. The ink spraying process for the 3D glass cover plate according to claim 1, characterized in that, In step S3, the photocurable resin system comprises at least one or a combination of the following components: acrylate oligomers, polyurethane acrylates, epoxy acrylates, or polyester acrylates; wherein the number average molecular weight of the photocurable resin system is 800-5000; the solvent system comprises one or a combination of the following components: propylene glycol methyl ether acetate, cyclohexanone, ethyl acetate, γ-butyrolactone, or dimethyl carbonate; the coloring component is an organic pigment or an inorganic pigment; the organic pigment includes phthalocyanine blue, phthalocyanine green, and quinacrine. The inorganic pigments include titanium dioxide, iron oxide, or carbon black, and the coloring components are dispersed before being added to step S3 so that their D90 particle size in the ink is ≤1.5μm; the leveling and wetting agent is at least one of the following substances: polyether-modified silicone oil, acrylate leveling agent, or fluorinated surfactant; the surface tension modifier is fluorinated modified acrylate, silicon-containing low molecular weight surface modifier, or a combination thereof, to control the surface tension of the spray ink at 25°C to 22-32mN / m.

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