A method for color development and positioning of graphic glue based on transfer technology

Abstract

The present invention relates to the technical field of graphic positioning cutting, and particularly to a method for graphic glue color development positioning based on a transfer technology, comprising the following steps: coating graphic glue on the surface of a substrate and drying it; covering the entire substrate with a transfer substrate attached with a color-developing material, and applying an initial pressure to make the color-developing material contact the graphic glue; applying an adjustable axial pressure gradient to a pressure roller, dynamically adjusting the hot pressing parameters through feedback from sensors, and forcibly cooling the glue to a set viscosity after the pressure roller detaches; peeling the transfer substrate at a gradually changing angle and variable speed, and maintaining the peeling tension within a range. The present invention effectively avoids the defect of particle adhesion caused by uneven local curing of the glue in the traditional process by controlling the thickness gradient of ethanol spraying and three-stage temperature-controlled drying, significantly improves the color development uniformity, and solves the "white spot" and "accumulation" problems of the traditional process.

Description

Technical Field

[0001] The present invention relates to the technical field of graphic positioning cutting, and particularly to a graphic glue color development positioning method based on a transfer technology. Background Art

[0002] In the graphic positioning cutting industry, visual assist positioning technology is the core link to ensure high-precision processing. In traditional processes, due to its invisibility, transparent glue is difficult to be directly recognized by the visual system, and special color development means are required to mark the graphic area. The existing technologies mainly achieve glue color development through two schemes: photonic crystal photoluminescence technology and ink and glue overprinting technology. However, among them, the color development of the photonic crystal technology has high uniformity, but it relies on a complex optical system and high-energy consumption UV curing; the overprinting technology has low cost, but the accuracy is limited.

[0003] Chinese Patent CN118698836A avoids overprinting errors by applying glue and pressing color development particles at one time. Specifically, an aluminumized microcrystal or a carbon ribbon is transferred to the glue area through a pressure roller, and color development is achieved by using the adhesiveness of the glue. However, uneven pressure distribution of the pressure roller results in local "white spots" (particles not attached) or "accumulation" (particles over-aggregated) in the color development area, and the highly elastic pressure roller is prone to deformation. Although secondary pressing can improve the transfer efficiency, it causes a reduction in line speed and an increase in energy consumption.

[0004] Therefore, developing a transfer color development process that can achieve high-uniform attachment of particles, efficient transfer, and adaptation to high-speed production has become a technical problem that urgently needs to be solved in the field of graphic positioning cutting.

[0005] The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present invention, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to provide a graphic glue color development positioning method based on a transfer technology, which solves the problem of uneven pressure distribution in a single transfer process through zoned and pressure dynamic control and optimization of the glue-particle adhesion force, and realizes uniform attachment of color development particles.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A graphic glue color development positioning method based on a transfer technology, comprising the following steps:

[0009] S1 Coating graphic glue on the surface of a substrate and drying it;

[0010] S2 Completely covering the substrate with a transfer substrate attached with a color development material, and applying an initial pressure to make the color development material contact the graphic glue;

[0011] S3 applies an adjustable axial pressure gradient to the pressure roller to compensate for the uneven pressure distribution of the pressure roller. The hot pressing parameters are dynamically adjusted through sensor feedback. After the pressure roller is disengaged, forced cooling is performed to make the glue reach the set viscosity;

[0012] S4 peels the transfer substrate at a gradually changing angle and variable speed, and maintains the peeling tension range.

[0013] Furthermore, in step S1, the pattern glue is coated on the surface of the substrate by screen printing, spraying or spin coating, and the coating amount of the glue is 0.5 - 5.0 g / m 2 . The pattern glue is one or two of polymer glue, epoxy resin glue, solvent glue and water-based glue, and the curing agent of the glue is any one of epoxy resin curing agent, isocyanate curing agent or ultraviolet curing agent.

[0014] Furthermore, in step S1, the drying is achieved by solution spraying and gradient drying. The volatile solution is an aqueous ethanol solution, and the volume concentration of ethanol is 70% - 90%. In the present invention, spraying ethanol preferentially dissolves the polar groups (such as hydroxyl groups and carboxyl groups) on the surface layer of the glue to promote local condensation reactions; then through gradient drying, heating at 60°C accelerates the volatilization of ethanol, and the remaining Si - OH dehydrates to form a Si - O - Si network. In the locally high - concentration area formed by electrostatic atomization spraying of the aqueous ethanol solution on the glue surface, the high - concentration ethanol area preferentially initiates surface cross - linking and inhibits lateral heat diffusion, solving the problem of pattern blurring caused by heat diffusion. Those skilled in the art can select other solutions with the ability to dissolve hydroxyl or carboxyl groups, such as isopropanol, acetone, etc.

[0015] Furthermore, the spraying of the aqueous ethanol solution uses a fan - shaped atomizing nozzle to form a gradient coating with a thin center and thick edges on the surface of the pattern glue, and the spraying amount is 0.05 - 0.15 mL / m 2 , the droplet diameter is 5 - 30 μm, among which, the ethanol coverage thickness in the central area is 5 - 10 μm, and the ethanol coverage thickness in the edge area is 20 - 30 μm.

[0016] Furthermore, the gradient drying forms a curing gradient from the surface to the inside, specifically including:

[0017] The first stage: drying at 40 ± 2°C for 20 - 30 s to reduce the volume concentration of ethanol;

[0018] The second stage: drying at 60 ± 5°C for 10 - 15 s to trigger the entanglement of the glue molecular chains;

[0019] The third stage: cooling and curing at 25 ± 3°C for 5 - 8 s to form a dry layer.

[0020] Furthermore, in step S2, the transfer substrate attached with the color - showing material from bottom to top is successively the color - showing material, the release layer and the carrier layer;

[0021] The color - developing material is electro - aluminum or carbon ribbon, with a thickness of 0.05 - 2μm;

[0022] The release layer is silicone oil, wax or fluorinated polymer, with a thickness of 0.1 - 0.5μm;

[0023] The carrier layer is made of PET or OPP material, with a thickness of 12 - 50μm.

[0024] Further, in step S2, the initial pressure is applied by a pressure roller, the pressure value is 5 - 15N, and the pressure application time is 3 - 5s.

[0025] Further, in step S3, the axial pressure gradient increases from the center of the pressure roller to the edge to compensate for the pressure loss at the edge of the pressure roller. The pressure in the edge area of the pressure roller is 10% - 20% higher than that at the center. The lamination temperature of the pressure roller is 80 - 85°C, the lamination time is 1.5 - 2.5s. After the pressure roller detaches, within 5 seconds, the glue is rapidly cooled by forced air cooling with a wind speed of 3 - 5m / s, and the included angle between the cooling air flow and the surface of the pressure roller is 30° - 45°.

[0026] Further, in step S4, the initial peeling angle is 15 - 20°, the final peeling angle is 60 - 70°, and the peeling speed increases uniformly from 0.1m / min to 5m / min; the peeling tension is 3 - 5N / m, and the tension fluctuation ≤ ±0.3N / m.

[0027] Further, in step S4, the rate of change of the peeling angle is 0.5 - 1.0° / s.

[0028] The beneficial effects of the present invention are as follows:

[0029] The present invention adopts the ethanol gradient spraying + three - stage drying process to form a dry layer on the surface of the glue, ensuring the uniform adhesion of the color - developing material. By controlling the thickness gradient of the ethanol spray and the three - stage temperature - controlled drying, it effectively avoids the particle adhesion defects caused by uneven local curing of the glue in the traditional process, significantly improves the color - developing uniformity, and solves the "white spot" and "accumulation" problems of the traditional process. On this basis, through the dynamic compensation of the axial pressure gradient, the lamination process of the pressure roller is optimized, and forced air cooling is used for rapid curing, so that the overall line speed is increased. In addition, in the peeling stage, a gradual angle + variable - speed peeling is adopted to ensure the stability under high - speed peeling, avoid particle re - adhesion or substrate fracture, improve the production efficiency, and meet the requirements of high - speed production lines. Specific Embodiments

[0030] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used in the specification of this invention are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0032] The raw materials or reagents used in the embodiments and / or comparative examples of the present invention are all purchased from mainstream manufacturers in the market. For those without specified manufacturers or concentrations, they are all analytical pure-grade raw materials or reagents that can be obtained conventionally. As long as they can achieve the expected effects, there are no special restrictions. The instruments and equipment used in this embodiment are all purchased from major manufacturers in the market. As long as they can achieve the expected effects, there are no special limitations. For those without specified specific technologies or conditions in this embodiment, they are carried out according to the technologies or conditions described in the literature in this field or according to the product specifications.

[0033] A graphic glue color development positioning method based on transfer technology includes the following steps:

[0034] S1 Coat graphic glue on the substrate surface and dry it.

[0035] S2 Cover the transfer substrate with the attached color-developing material entirely on the substrate, and apply an initial pressure to make the color-developing material contact the graphic glue.

[0036] S3 Apply an adjustable axial pressure gradient to the pressure roller to compensate for the uneven pressure distribution of the pressure roller. The hot pressing parameters are dynamically adjusted through sensor feedback. After the pressure roller disengages, forced cooling is carried out to make the glue reach the set viscosity.

[0037] S4 Peel the transfer substrate at a gradually changing angle and variable speed, and maintain the peeling tension range.

[0038] The present invention utilizes the surface tension difference between ethanol and glue (glue 52 mN / m, ethanol 22 mN / m) to induce Marangoni convection, so that the distribution of ethanol presents a gradient structure with a thin center and a thick edge, thereby avoiding the edge shrinkage defect caused by traditional spraying. The three-stage gradient drying directionally regulates the arrangement of glue molecular chains through the temperature-viscosity coupling effect, forming a structure with both surface hardness and underlying adhesion, improving the subsequent imprinting effect. The axial pressure gradient in the imprinting stage compensates for the edge low-pressure effect, increasing the transfer efficiency to more than 95%. The gradually changing angle and variable speed control in the peeling stage avoid particle re-adhesion or substrate damage by dynamically adjusting the interfacial fracture energy density, significantly improving the color development uniformity, and solving the "white spots" and "accumulation" problems of traditional processes.

[0039] Specifically, in step S1, the applied graphic glue is transparent and invisible after drying. In this application, through transfer printing, it becomes colored, facilitating positioning and improving the accuracy of image cutting. The graphic glue is applied to the surface of the substrate by screen printing, spraying or spin coating, and the coating amount of the glue is 0.5 - 5.0 g / m 2 . Among them, screen printing has improved edge clarity of the pattern and is suitable for high-viscosity glues (3500 - 4500 cps), such as UV-curable epoxy resins and thermosetting silicones; the spraying method is suitable for complex curved substrates, and the film thickness uniformity is better than that of traditional dispensing, and the applicable glue types are such as fast-drying acrylics and waterborne polyurethanes; the spin coating method can achieve sub-micron thickness control for low-viscosity materials (<2000 cps) such as photoresists and transparent conductive adhesives, and those skilled in the art can select a suitable coating process.

[0040] Specifically, in step S1, the drying is achieved through solution spraying and gradient drying.

[0041] In this embodiment, the volatile solution is an ethanol aqueous solution, and the volume concentration of ethanol is 70% - 90%. In the present invention, spraying ethanol preferentially dissolves the polar groups (such as hydroxyl and carboxyl groups) on the surface layer of the glue, promoting local condensation reactions; then through gradient drying, heating at 60°C accelerates the volatilization of ethanol, and the remaining Si-OH dehydrates to form a Si-O-Si network. In the locally high-concentration area formed on the glue surface by electrostatic atomization spraying of the ethanol aqueous solution, the high-concentration ethanol area preferentially initiates surface cross-linking and inhibits lateral heat diffusion, solving the problem of pattern blurring caused by heat diffusion.

[0042] Among them, the ethanol aqueous solution is sprayed using a fan-shaped atomizing nozzle to form a gradient coating with a thin center and thick edges on the surface of the graphic glue. For example, main nozzles are arranged in the center area and auxiliary nozzles are arranged in the edge area, and the flow rates of the center area and the edge area are distributed. The spraying amount is 0.05 - 0.15 mL / m 2 , the droplet size is 5 - 30 μm. Among them, the ethanol coverage thickness in the center area is 5 - 10 μm, and the ethanol coverage thickness in the edge area is 20 - 30 μm. The fan-shaped atomizing nozzle controls the droplet distribution by adjusting the spraying distance. The gradient design of small particle sizes in the center area and large particle sizes in the edge area matches the surface tension distribution of the glue. The design of a thin middle and thick edges can avoid excessive hardening in the center area caused by too fast ethanol volatilization, reduce the hardness difference between the center area and the edge area, and the large particle size droplets penetrate deeper in the edge area, enhancing the edge adhesion and reducing the interfacial failure during peeling.

[0043] The gradient drying forms a curing gradient from the surface to the inside, specifically including:

[0044] In the first stage, drying at 40±2℃ for 20 - 30s reduces the volume concentration of ethanol. Drying at 40℃ at low temperature allows ethanol to slowly volatilize from the surface of the glue, avoiding skin formation on the glue surface caused by rapid volatilization. The ethanol concentration gradient forms a viscosity gradient from the surface to the interior, providing a directional guide for the subsequent entanglement of molecular chains.

[0045] In the second stage, drying at 60±5℃ for 10 - 15s triggers the entanglement of glue molecular chains. 60℃ is close to the glass transition temperature (Tg) of the glue, causing local disentanglement and rearrangement of molecular chains. Solvent volatilization inside the glue forms nano - scale pore channels (pore diameter 50 - 200nm), providing space for the embedding of chromogenic particles.

[0046] In the third stage, cooling and curing at 25±3℃ for 5 - 8s rapidly vitrifies the glue, freezing the molecular chain network and pore structure, solidifying and locking the pore structure to form a dry layer.

[0047] In the present invention, gradient cooling can reduce stress concentration inside the glue, reduce micro - cracks in the hardened layer. The pore diameter of the dry layer formed after curing is 50 - 200nm, providing space for particle embedding and enhancing the bonding force of the chromogenic layer.

[0048] Specifically, in step S2, the transfer substrate attached with the chromogenic material from bottom to top is the chromogenic material, the release layer, and the carrier layer in sequence.

[0049] The chromogenic material is aluminumized paper or carbon tape, with a thickness of 0.05 - 2μm. Ultra - thin aluminumized paper is light - transmissive and suitable for scenarios such as OLED screens that require backlight detection. Thicker carbon tape can provide high conductivity and is suitable for flexible circuits to directly serve as wires. The microcrystals of aluminumized paper can be modified with stearic acid to reduce the surface energy, and the adhesion force ratio with the glue is controlled at 1.2 - 1.5:1 to ensure that the chromogenic material is preferentially released from the release layer and prevent the particles from sticking back to the carrier layer after transfer.

[0050] The release layer is silicone oil, wax, or fluorinated polymer, with a thickness of 0.1 - 0.5μm, providing a controllable peeling force. A low - thickness release layer can achieve monolayer coverage, avoiding transfer defects caused by uneven thickness.

[0051] The carrier layer is made of PET or OPP material, with a thickness of 12 - 50μm, which can balance flexibility and stiffness and avoid wrinkles in the transfer film.

[0052] The initial pressure is applied by a pressure roller, with a pressure value of 5 - 15N and a pressure application time of 3 - 5s. A low pressure of 10N ensures uniform initial contact, avoiding local deformation or displacement misalignment of highly elastic chromogenic materials (such as aluminumized paper) caused by sudden pressure, and facilitating the promotion of particle embedding into the glue pores in the subsequent high - pressure stage. Moreover, there may be micron - level unevenness or residual bubbles on the glue surface. The progressive contact with low pressure (5 - 15N) allows bubbles to slowly escape, improving the transfer uniformity.

[0053] Specifically, in step S3, the axial pressure gradient increases from the center of the pressure roller to the edge, and the pressure in the edge area of the pressure roller is 10% - 20% higher than that at the center. It should be noted that the pressure roller providing the initial pressure and the pressure roller realizing the radial pressure compensation for lamination work independently.

[0054] Among them, the axial pressure gradient is used to compensate for the edge pressure loss of the pressure roller; when the pressure roller is under pressure, natural deformation will occur due to the elasticity of the material, resulting in the actual contact pressure at the edge being lower than that at the center. Through the active design of reverse pressure gradient compensation, the present invention can offset the influence of deformation. After compensation, the difference in the transfer efficiency of the color-developing particles between the edge and the center is reduced from 15% to ≤3%, and there is no "whitening" defect in the edge area. Moreover, the uniform pressure distribution can reduce local wear and extend the service life of the pressure roller. For example, coating layers of different materials can be arranged along the axial direction of the pressure roller to form an elastic strain gradient to compensate for the actual contact pressure in the edge area.

[0055] Specifically, the pressure difference between adjacent coating areas is ≤0.05 MPa. The pressure roller is set at 80 - 85 °C to pre-soften the glue, activate surface cross-linking, achieve core lamination, and embed the color-developing layer. Specifically, it can be realized by embedding a ring-shaped heating wire inside the existing pressure roller for regulation. The lamination time of the pressure roller is 1.5 - 2.5 s. At the lamination temperature, the glue molecules unwind and rewind within 1.5 - 2.5 s, maximizing the transfer efficiency. Controlling the lamination time can limit the flow distance of the glue to ≤50 μm to avoid glue overflow.

[0056] Within 5 seconds after the pressure roller detaches, the glue is rapidly cooled by forced air cooling with a wind speed of 3 - 5 m / s, and the angle between the cooling air flow and the surface of the pressure roller is 30° - 45°. The air flow at an angle of 30 - 45° forms an eddy current effect, enabling the cooling rate of the glue to reach 15 - 20 °C / s from 80 - 85 °C to 45 °C, which is much higher than natural cooling. The rapid cooling can quickly pass through the glass transition temperature (Tg), freeze the pore structure, and inhibit the rebound of the color-developing particles.

[0057] In step S4, the initial peeling angle is 15 - 20°, the final peeling angle is 60 - 70°, and the peeling speed is uniformly increased from 0.1 m / min to 5 m / min; the peeling tension is 3 - 5 N / m, and the tension fluctuation is ≤±0.3 N / m. The gradual change of the peeling angle in cooperation with the speed increase stabilizes the interfacial fracture energy density at 0.8 - 1.2 J / m 2 , with less fluctuation compared to the traditional process;

[0058] Initially, the release layer interface is preferentially separated by small-angle peeling to avoid premature fracture at the interface between the color-developing material and the glue. At the end section, large-angle peeling makes the fracture energy concentrate at the color-developing material-glue interface to ensure complete separation. Variable-speed peeling controls the initial low speed to ensure uniform initiation of the peeling front, and the high speed at the end section matches the production line rhythm. At the same time, the back adhesion is inhibited through the inertial effect, and the control of the tension reduces the position deviation caused by the tension fluctuation and decreases the stretching deformation rate of the substrate.

[0059] The rate of change of the peeling angle is 0.5 - 1.0° / s. By controlling the rate of change of the angle to match the critical speed of crack propagation, the peeling trajectory optimization stabilizes the interfacial fracture energy density at 0.8 - 1.2 J / m 2 , reducing the residual amount of the release layer and avoiding the "stick-slip" effect caused by sudden angle changes.

[0060] Example 1

[0061] In this example, a PET film with a thickness of 125 μm is used as the substrate. A 300-mesh screen printing stencil is used, the blade angle is 60°, and the pressure is 0.3 MPa. Graphic glue is coated on the substrate surface. The glue selected is UV-curable acrylate glue with a viscosity of 3500 cps and a solid content of 68%. The coating thickness is controlled at 20 ± 2 μm, and the pattern accuracy is ±5 μm. An ethanol aqueous solution is prepared by mixing ethanol with a purity of 99.7% and deionized water at a volume ratio of 8:2. A fan-shaped atomizing nozzle is used, the spraying distance is 12 cm, and the moving speed is 0.5 m / s to form a gradient coating; among them, the spraying amount in the central area is 5 μL / cm 2 , the thickness is 8 ± 1 μm, and the spraying amount in the edge transition area is 15 μL / cm 2 , the thickness is 25 ± 2 μm, and then gradient drying is adopted to form a hardened layer with a surface hardness reaching 2H;

[0062] Among them, the gradient drying includes: the first stage: hot air drying at 40°C with a wind speed of 1.5 m / s for 25 s, and the ethanol concentration gradient drops to 45%; the second stage: infrared heating at 60°C, the infrared wavelength is 950 nm, and the power density is 0.8 W / cm 2 , drying for 12 s; the third stage: cooling at room temperature for 7 s, and the surface hardness of the hardened layer reaches 2H;

[0063] Then, the transfer substrate with the color-developing material attached is fully covered on the substrate. During the transfer process, a rubber pressure roller contacts with a linear pressure of 10 N / mm for 3 s to make the color-developing material contact with the graphic glue. Specifically, the transfer substrate includes: a 50-μm-thick OPP film as the carrier layer, a 0.3-μm-thick fluorosilicone resin as the release layer, and a 0.8-μm-thick electroaluminum as the color-developing layer;

[0064] After that, an adjustable axial pressure gradient is applied to the pressure roller to compensate for the uneven pressure distribution of the pressure roller. Specifically, the pressure gradient is 20 N / mm at the center pressure, linearly increasing to 23 N / mm towards both ends, the temperature is 80 °C. After the pressure roller disengages, the cooling air flow forms a 40° angle with the pressure roller, the wind speed is 4 m / s, and the glue temperature is reduced from 80 °C to 45 °C within 5 s, and the viscosity is stabilized at 3200 ± 200 cps.

[0065] Finally, with an initial peeling angle of 18°, a final peeling angle of 68°, an angle change rate of 0.8° / s, the peeling speed is controlled at 0.1 to 5 m / min, the transfer printing substrate is peeled, and the tension is controlled at 4.2 ± 0.2 N / m. The color rendering uniformity is tested by an X-Rite eXact spectrophotometer, and the measured CV value is 5.3%. The transfer efficiency is measured by the gravimetric method to be 97.1%.

[0066] Example 2

[0067] This example specifically illustrates the application of the transfer printing color rendering positioning technology of the present invention in the precision cutting of OLED screens. Taking the special-shaped cutting of a 6.7-inch flexible OLED display screen as an example, it is necessary to complete the cutting of an arc profile with a radius of curvature R = 2 mm on a 0.3 mm thick PI substrate, and the cutting accuracy requirement is ±5 μm.

[0068] First, a UV-curable polyurethane acrylate pattern glue is coated on the surface of the pretreated substrate. An ethanol aqueous solution is prepared by mixing ethanol with a purity of 99.7% and deionized water in a volume ratio of 8:2. A fan-shaped atomizing nozzle is used, the spraying distance is 12 cm, and the moving speed is 0.5 m / s to form a gradient coating; among them, the spraying amount in the central region is 5 μL / cm 2 , the thickness is 8 ± 1 μm, and the spraying amount in the edge transition region is 15 μL / cm 2 , the thickness is 25 ± 2 μm, and then gradient drying is adopted to form a hardened layer with a surface hardness reaching 2H;

[0069] Among them, the gradient drying includes: the first stage: hot air drying at 40 °C with a wind speed of 1.5 m / s for 25 s, and the ethanol concentration gradient is reduced to 45%; the second stage: UV-LED curing (365 nm, 80 mW / cm 2 ) for 8 s, and the hardness reaches 3H; the third stage: cooling at room temperature for 7 s, and the surface hardness of the hardened layer reaches 2H;

[0070] Then, the transfer printing substrate with the color rendering material attached is fully covered on the substrate. During the transfer printing process, a rubber pressure roller is used to contact with a linear pressure of 10 N / mm for 3 s to make the color rendering material contact with the pattern glue. Specifically, the transfer printing substrate includes: a 50 μm thick COP film as the carrier layer, a 0.3 μm thick silicone-containing polyurethane as the release layer, and a 1 μm thick carbon tape as the color rendering layer;

[0071] After that, an adjustable axial pressure gradient is applied to the pressure roller to compensate for the uneven pressure distribution of the pressure roller. Specifically, the pressure gradient is 20 N / mm at the center pressure, linearly increasing to 24 N / mm towards both ends, the temperature is 75 °C. After the pressure roller disengages, the cooling air flow forms an angle of 40° with the pressure roller, the wind speed is 4 m / s, and the glue temperature is reduced from 75 °C to 40 °C within 5 s, and the viscosity is stabilized at 3200 ± 200 cps.

[0072] Finally, with an initial peeling angle of 15°, a final peeling angle of 65°, an angle change rate of 1° / s, the peeling speed is controlled at 0.1 to 5 m / min, the transfer substrate is peeled, and the tension is controlled at 3.8 ± 0.2 N / m. The color rendering uniformity is tested by an X-Rite eXact spectrophotometer, and the measured CV value is 5.5%. The transfer efficiency is measured to be 96.9% by the gravimetric method.

[0073] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A graphic glue color development positioning method based on transfer printing technology, characterized in that It includes the following steps: S1 Coat pattern glue on the substrate surface and dry it. S2 Cover the transfer substrate with the color-developing material attached thereon entirely on the substrate, and apply an initial pressure to make the color-developing material contact with the pattern glue. S3 Apply an adjustable axial pressure gradient to the pressure roller, and after the pressure roller detaches, forcibly cool the glue to a set viscosity. S4 Peel the transfer substrate at a gradually changing angle and variable speed, and maintain the peeling tension range. In step S1, the drying is achieved through solution spraying and gradient drying. The solution spraying is to use a volatile solution, adopt a fan-shaped atomizing nozzle, and form a gradient coating with a thin center and thick edges on the surface of the pattern glue. The solution coverage thickness in the central area is 5 - 10 μm, and the solution coverage thickness in the edge area is 20 - 30 μm. The volatile solution is an ethanol aqueous solution.

2. The method for color development positioning of graphic glue based on a transfer technology according to claim 1, wherein, In step S1, the pattern glue is coated on the substrate surface by screen printing, spraying or spin coating.

3. A graphic glue color development positioning method based on a transfer technology according to claim 1, characterized in that, The volume concentration of ethanol in the ethanol aqueous solution is 70% - 90%.

4. A graphic glue color development positioning method based on a transfer technology according to claim 1, characterized in that In step S1, the gradient drying includes: In the first stage, dry at 40 ± 2 °C for 20 - 30 s to reduce the solvent volume concentration. In the second stage, dry at 60 ± 5 °C for 10 - 15 s to trigger the entanglement of the glue molecular chains. In the third stage, cool and cure at 25 ± 3 °C for 5 - 8 s to form a dry layer.

5. A method for color development and positioning of graphic glue based on a transfer technology according to claim 1, characterized in that, In step S2, the transfer substrate with the color-developing material attached thereon successively includes a color-developing material, a release layer and a carrier layer from bottom to top. The color-developing material is an aluminized paper or a carbon ribbon, with a thickness of 0.05 - 2 μm. The release layer is silicone oil, wax or fluorinated polymer, with a thickness of 0.1 - 0.5 μm. The carrier layer is a PET or OPP material, with a thickness of 12 - 50 μm.

6. A graphic glue color development positioning method based on a transfer printing technique according to claim 1, characterized in that, In step S2, the initial pressure is applied by a pressure roller, the pressure value is 5 - 15 N, and the pressure application time is 3 - 5 s.

7. A method for color development and positioning of graphic glue based on a transfer technology according to claim 1, characterized in that, In step S3, the axial pressure gradient increases from the center of the pressure roller to the edge, and the pressure in the edge area of the pressure roller is 10% - 20% higher than that in the center. The pressing temperature of the pressure roller is 80 - 85 °C, the pressing time is 1.5 - 2.5 s, and within 5 seconds after the pressure roller detaches, the glue is rapidly cooled by forced air cooling with a wind speed of 3 - 5 m / s, and the included angle between the cooling air flow and the surface of the pressure roller is 30° - 45°.

8. A method for color development and positioning of graphic glue based on transfer technology according to claim 1, characterized in that, In step S4, the initial peeling angle is 15 - 20 °, the final peeling angle is 60 - 70 °, and the peeling speed is uniformly increased from 0.1 m / min to 5 m / min. The peeling tension is 3 - 5 N / m, and the tension fluctuation ≤ ±0.3 N / m.

9. A method for color development and positioning of graphic glue based on a transfer technology according to claim 8, characterized in that, In step S4, the rate of change of the peeling angle is 0.5 - 1.0 ° / s.