Thermal dye sublimation ribbon with multiple dye diffusion prevention mechanisms and preparation method of thermal dye sublimation ribbon

Abstract

The invention relates to the technical field of thermal dye sublimation printing, in particular to a thermal dye sublimation ribbon with multiple dye diffusion prevention mechanisms and a preparation method of the thermal dye sublimation ribbon. A dye layer of the colored tape comprises a first dye sub-layer and a second dye sub-layer, the first dye sub-layer is attached to a bottom coating, and the second dye sub-layer is attached to the first dye sub-layer; in the first dye layer, the mass ratio of the dye to the resin is 1.5: 1-2.4: 1, and in the second dye layer, the mass ratio of the dye to the resin is 0.7: 1-1.5: 1. The dye layer of the sublimation ribbon adopts an innovative double-layer structure, the first dye layer adopts a higher dye-to-resin ratio to ensure that the printing color density meets the requirement, and the second dye layer adopts a lower dye-to-resin ratio to remarkably improve the printing precision and image definition to construct an anti-diffusion barrier; high color density and anti-diffusion and anti-migration performance can be considered, and the quality of continuous color gradation printing patterns of the thermal dye sublimation colored tape is comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of sublimation printing technology, and more specifically, to a sublimation ribbon with multiple anti-dye diffusion mechanisms and its preparation method. Background Technology

[0002] Dye-sublimation printing is an imaging technology based on thermally controlled dye transfer. Its working principle involves locally heating the ribbon with a thermal printhead, causing the sublimated dye in the dye layer to vaporize and transfer to the surface of the substrate to form an image. This technology is widely used in high-value-added fields such as flexible label printing, ID card production, and digital photography due to its ability to achieve continuous color gradation reproduction, natural color transitions, and high image detail.

[0003] In the actual process of thermal sublimation printing, the thermal diffusion behavior of the dye is a key factor affecting image quality. Theoretically, the dye should be uniformly transferred to the substrate in the vertical direction. However, under actual printing conditions, due to the non-uniformity of heat conduction, the existence of dye concentration gradients, and the complexity of resin thermodynamic properties, the dye is prone to lateral diffusion at the edges of the heated area. This diffusion directly leads to blurred edges of printed lines and a significant decrease in image sharpness.

[0004] Currently, dye-sublimation ribbons are widely used in soft labels, ID cards and other fields. However, when pursuing high color density, they face a core technical contradiction: increasing the dye-to-resin ratio (D / B ratio) can enhance color density, but it will cause the dye to diffuse laterally during the printing process, resulting in blurred image edges and unclear color overlay. At the same time, it will also cause the dye to migrate to the back coating. The migrated dye may contaminate other color layers and unprinted areas, seriously affecting image quality and color characteristics.

[0005] The specific problems are as follows: 1. Dye diffusion and migration are prominent issues. Although increasing the dye ratio can enhance color density, it will cause the dye to diffuse laterally during the printing process, resulting in blurred image edges. At the same time, it will also cause the dye to migrate to the back coating, resulting in the phenomena of "dye migration to the heat-resistant slip layer" and "dye staining in unprinted areas".

[0006] 2. Limited material selection and high cost: Existing technologies rely on specific dye / resin combinations to suppress diffusion, resulting in a narrow range of material choices and high costs for special raw materials, which affects the economics and supply stability of the products.

[0007] To address the aforementioned issues, existing solutions include, on the one hand, inhibiting migration through specific dye and resin combinations, but the choice of materials is limited; on the other hand, adjusting the dye ratio or adding auxiliaries in a single dye layer, but it is difficult to balance color density and anti-diffusion performance; or adding alumina, silica, or other sols to the base layer to block dye migration, but this approach weakens the adhesion between the base layer and the dye layer, increasing the risk of color fading.

[0008] For example, patent JP2015-51539A inhibits migration through a specific dye / resin combination, but it has problems such as a narrow range of material selection, high cost, and limited applicability, and it is difficult to simultaneously achieve high color density and anti-diffusion and anti-migration performance. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a thermal sublimation ribbon with multiple anti-dye diffusion mechanisms and a preparation method thereof.

[0010] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: This invention provides a sublimation ribbon with multiple anti-dye diffusion mechanisms, comprising a base coating layer, wherein a dye layer is disposed on the base coating layer; the dye layer comprises a first dye layer and a second dye layer, wherein the first dye layer is attached to the base coating layer and the second dye layer is attached to the first dye layer; in the first dye layer, the mass ratio of dye to resin is 1.5:1-2.4:1, and in the second dye layer, the mass ratio of dye to resin is 0.7:1-1.5:1.

[0011] Based on the above technical solution, the present invention can be further improved as follows.

[0012] Furthermore, the resin in the first dye layer is a first resin, and the glass transition temperature (Tg) of the first resin is greater than 70°C; the resin in the second dye layer is a second resin, and the glass transition temperature (Tg) of the second resin is 50-65°C.

[0013] Furthermore, the first resin and the second resin are each independently selected from one or more of the following: polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methylcellulose, polyurethane, polycarbonate, polyester resin, etc.

[0014] Furthermore, the resin mass in each layer is 2%-15% of the total mass of each layer.

[0015] Furthermore, the first dye layer and the second dye layer each have multiple color regions, and each color region in the first dye layer and the second dye layer corresponds one-to-one.

[0016] Furthermore, both the first dye layer and the second dye layer further include a curing agent, which is an isocyanate compound. Furthermore, the mass of the solid filler is 0.2%-0.4% of the total amount of resin and dye in its layer.

[0017] Furthermore, the total thickness of the dye layer is 0.5-1.2 μm, and the thickness of the first dye layer accounts for 40%-60% of the total thickness.

[0018] Furthermore, the resin in the base coating is one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methylcellulose, etc.; the base coating also includes a molecular-level interface modifier, which is one or more of silane coupling agents, titanate coupling agents, or zirconate aluminate coupling agents.

[0019] The present invention also provides a method for preparing a sublimation ribbon with multiple anti-dye diffusion mechanisms as described above, wherein the preparation steps of the dye layer in the preparation method are as follows: A first dye layering coating solution and a second dye layering coating solution are prepared using organic solvents respectively; the first dye layering coating solution is applied to the base layer and cured to obtain the first dye layer; then the second dye layering coating solution is applied to the first dye layer and cured to obtain the second dye layer.

[0020] Furthermore, the organic solvent is a methyl ethyl ketone (MEK)-toluene mixed solvent, with a mass ratio of MEK to toluene of 1:1 to 1:3; in each layer, the mass of the organic solvent is 80%-95% of the total mass of the layer.

[0021] The beneficial effects of this invention are as follows: (1) The sublimation ribbon of the present invention has multiple anti-dye diffusion mechanisms. The dye layer adopts an innovative double-layer structure. In the first dye layer, a higher dye to resin ratio is used to ensure that the printing color density meets the requirements. In the second dye layer, a lower dye to resin ratio is used to significantly improve printing accuracy and image clarity to build an anti-dye diffusion barrier. (2) The sublimation ribbon of the present invention has multiple anti-dye diffusion mechanisms. The gradient ratio design in the layered structure of the dye layer can realize the control of dye concentration distribution, so that the sublimation ribbon can effectively solve the problems of dye diffusion, migration and related image quality while maintaining high color density, thereby achieving the best balance between color density and anti-dye diffusion performance. (3) The sublimation ribbon of the present invention has multiple anti-dye diffusion mechanisms, which can take into account both high color density and anti-diffusion and anti-migration performance, and comprehensively improve the quality of continuous color gradation printing patterns of the sublimation ribbon. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the layer structure of the thermal sublimation ribbon with multiple anti-dye diffusion mechanisms of the present invention; Figure 2 This is a schematic diagram of the layer structure of the thermal sublimation ribbon in Embodiment 1 of the present invention.

[0023] The attached diagram lists the components represented by each number as follows: 1. Back coating; 2. Substrate; 3. Primer coating; 4. First dye layering; 41. First yellow layering; 42. First magenta layering; 43. First cyan layering; 43. 5. Second dye layering; 51. Second yellow layering; 52. Second magenta layering; 53. Second cyan layering. Detailed Implementation

[0024] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0025] The sublimation ribbon of the present invention with multiple anti-dye diffusion mechanisms includes a base layer 3, on which a dye layer 6 is provided; the dye layer 6 includes a first dye layer 4 and a second dye layer 5, the first dye layer 4 being attached to the base layer 3, and the second dye layer 5 being attached to the first dye layer 4; in the first dye layer 4, the mass ratio of dye to resin is 1.5:1-2.4:1, and in the second dye layer 5, the mass ratio of dye to resin is 0.7:1-1.5:1.

[0026] The present invention provides a sublimation ribbon with multiple anti-dye diffusion mechanisms. The dye layer 6 adopts an innovative double-layer structure. The first dye layer 4 uses a high dye-to-resin ratio (1.5:1 to 2.4:1), which mainly provides a sufficient dye source to ensure that the printing color density meets the requirements. The second dye layer 5 uses a lower dye-to-resin ratio (0.7:1 to 1.5:1). The components of this layer can form a dense polymer network. This network effectively inhibits the lateral diffusion and longitudinal migration of dye molecules through physical barrier, thereby blocking and controlling the lateral diffusion of dye. During the heating process, it prevents dye migration, significantly improves printing accuracy and image clarity, and builds an anti-dye diffusion barrier.

[0027] The gradient ratio design in the layered structure of the dye layer 6 described above can control the dye concentration distribution. The chemical potential gradient generated by the dye concentration difference can guide the dye to preferentially transfer vertically towards the substrate during the printing process, so that the sublimation ribbon can effectively solve the problems of dye diffusion, migration and related image quality while maintaining high color density, thereby achieving the best balance between color density and anti-diffusion performance.

[0028] The sublimation ribbon of the present invention has multiple anti-dye diffusion mechanisms, which take into account both high color density and anti-diffusion and anti-migration performance, and comprehensively improve the quality of continuous color gradation printing patterns of the sublimation ribbon.

[0029] Preferably, the resin in the first dye layer 4 is a first resin with a glass transition temperature (Tg) greater than 70°C; the resin in the second dye layer 5 is a second resin with a glass transition temperature (Tg) of 50-65°C.

[0030] Increasing the amount of resin added can enhance the binding force on the dye, thus achieving a better anti-diffusion effect, but it will also hinder the normal sublimation of the dye during printing, reducing the printing color density. Conversely, reducing the amount of resin added, while beneficial for dye sublimation, will weaken the fixation effect on the dye if the amount is too low, increasing the risk of dye diffusion. Therefore, in resin selection, the first resin of the first dye layer 4 has a higher glass transition temperature to enhance the stability of the dye during storage and prevent pre-migration; the second resin of the second dye layer 5 is selected from resins with relatively lower glass transition temperatures, possessing appropriate chain segment mobility at printing temperatures, ensuring both sufficient dye sublimation and maintaining sufficient network structure strength to inhibit dye diffusion.

[0031] Meanwhile, based on the selection of the first and second resins mentioned above, the resin mass in each layer is 2%-15% of the total mass of each layer, preferably 2%-5%. By precisely controlling the resin content, the best balance between anti-diffusion and color density can be achieved.

[0032] The dyes used in the dye layer 6 of the present invention are not particularly limited and can be selected from a variety of sublimation dyes, preferably dyes with low melting and sublimation temperatures and good solubility.

[0033] The first and second resins are used as binders for the dyes mentioned above, and preferably one or more of the following: polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methylcellulose, polyurethane, polycarbonate, and polyester resin.

[0034] Preferably, a curing agent may be added to the first dye layer 4 and the second dye layer 5. The curing agent can form a three-dimensional cross-linked network structure in the resin system through a cross-linking reaction, which effectively restricts the migration of dye molecules.

[0035] Preferably, the curing agent is an isocyanate compound, and the mass of the added agent is 1%-10% of the mass of the resin in the layer it is in; in this way, the three-dimensional cross-linked network formed can significantly enhance the structural stability of the dye layer and further improve the anti-diffusion effect.

[0036] To optimize the anti-diffusion performance of the second dye layer, a certain amount of solid filler can be added. These fillers can form dispersed physical barrier points in the coating, effectively extending the migration path of dye molecules and inhibiting their lateral and longitudinal diffusion. At the same time, the addition of fillers also helps to reduce the direct contact area between the dye layer and the back coating in high temperature and high humidity environments, thereby further preventing adhesion between the two layers and ensuring print quality and reliability.

[0037] Preferably, the solid filler is polymethyl methacrylate (PMMA) or silica, with PMMA being preferred due to its advantages such as high mechanical strength, good light transmittance, and low cost.

[0038] The amount of solid filler added is 0.2%-0.4% of the total amount of resin and dye in the second dye layer 5. This amount can effectively construct diffusion barrier points in the second dye layer 5, while avoiding the impact of excessive filler on the surface smoothness.

[0039] In terms of color configuration, the preferred option is to set three colors: yellow, magenta, and cyan. Each color adopts the above-mentioned double-layer anti-diffusion structure, and the dye layers 6 of different colors are continuously coated in different areas on the base coating layer 3.

[0040] Preferably, to achieve optimal color performance while preventing dye diffusion, the dye-to-resin ratio of each color layer can be precisely controlled. Specifically, in the yellow dye layer, the dye-to-resin ratio in the two layers is 1.4:1-0.8:1; in the magenta dye layer, the dye-to-resin ratio in the two layers is 1.8:1-1.2:1; and in the cyan dye layer, the dye-to-resin ratio in the two layers is 2:1-1.4:1. This differentiated design can meet the characteristic requirements of each color while ensuring the overall anti-diffusion effect.

[0041] To ensure the ribbon can withstand the high heat and pressure required for printing and to reduce the transfer of liquid lubricant from the substrate to the ribbon, preventing the ribbon from sticking to the substrate during printing, the slip properties of the dye layer 6 need to be increased. A certain amount of solid lubricant can be added to the dye layer 6 to improve the slip properties of the ribbon surface.

[0042] Considering that the dye layer 6 will come into direct contact with the back coating layer when the ribbon is wound up, in order to maintain good printing quality after the ribbon has been exposed to high temperature and high humidity, a solid lubricant with a high melting point is preferred to reduce the migration of dye and lubricant to the back coating layer.

[0043] Preferably, the solid lubricant is a solid lubricant with a melting point of about 60-70°C, such as pentaerythritol stearate, octadecyl erucamide, or erucamide. While providing slipperiness and reducing dye migration, it also has a certain effect on improving the color density of the lower color levels of the color band.

[0044] Preferably, the amount of solid lubricant added is 0.3%-5% of the total amount of resin and dye, and more preferably 1%-3%.

[0045] Preferably, the total thickness of the dye layer 6 is 0.5-1.2 μm, and the thickness of the first dye layer 4 accounts for 40%-60% of the total thickness. The above thickness limitation can ensure the dye supply and give full play to the anti-diffusion effect.

[0046] The main function of the base coating 3 is to improve the adhesion and dispersion of dye on the substrate, thereby improving the uniformity of the printed image and the vibrancy of the colors.

[0047] During the printing process, when heated, the dye diffuses in two opposite directions to the substrate and the adhesive layer. Therefore, the base coating 3 is preferably a resin or sol that can simultaneously meet the requirements of poor dye adsorption and good adhesion to the substrate 2. Cost and coating process also need to be considered.

[0048] Therefore, preferably, the resin in the base coating 3 of the present invention is one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methylcellulose, etc.

[0049] More preferably, the resin in the base coating 3 is a composite resin system of polyvinylpyrrolidone and polyvinyl alcohol, with a mass ratio of 1:1 to 3:1. By optimizing the arrangement density and cross-linking degree of the polymer molecular chains, the above composite resin system can form a dense network structure, which can further effectively block the migration of dye to the substrate.

[0050] Preferably, the base coating 3 also includes a molecular-level interface modifier; the molecular-level interface modifier can enhance the interfacial bonding between the base coating and the substrate 2, especially the PET substrate, and improve the barrier effect against dye migration.

[0051] Preferably, the molecular-level interface modifier is a silane coupling agent (such as γ-aminopropyltriethoxysilane), a titanate coupling agent (such as isopropyltris(dioctylpyrophosphate)titanate), or a zirconate aluminate coupling agent, etc. The above-mentioned molecular-level interface modifier, through its bifunctional structure, forms a chemical bond with the hydroxyl groups on the surface of the PET substrate at one end, and undergoes a cross-linking reaction with the functional groups of the resin in the undercoat 3 at the other end, thereby constructing a strong chemical bridging network in the interface region. At the same time, the densified interface structure can reduce the migration channels of dye molecules and enhance the barrier effect.

[0052] Preferably, the amount of molecular-level interface modifier added is 0.5%-3% of the total amount of resin in the primer layer 3, preferably 1%-2%. This range can ensure the formation of effective bridging while avoiding the degradation of coating performance caused by excessive addition.

[0053] In the thermal sublimation ribbon of the present invention, the substrate 2 can be any commercially available material with a certain degree of heat resistance and strength, such as polyethylene terephthalate film.

[0054] Preferably, the thickness of the substrate 2 is 4-125 μm, and the composition of the substrate 2 is PET film. More preferably, the thickness of the PET film substrate is 4.3-12.5 μm.

[0055] The sublimation ribbon of the present invention also includes a back coating 1. The main function of the back coating 1 is to adapt to the high-speed printing of the sublimation printer, improve the heat resistance and lubricity of the substrate 2, prevent adhesion and printing wrinkles caused by the heat of the thermal head during the printing process, and ensure the heat transfer of the print head without melting the substrate 2 under high heat printing conditions.

[0056] The resin in the back coating 1 can be PVB resin, cellulose resin, silicone-modified polyurethane, polyamide resin, etc.; preferably, it is a high acetal, high TG PVB resin with a molecular weight of 50,000-60,000 and a degree of polymerization of 300-1300.

[0057] Preferably, the resin in the back coating layer 1 accounts for 5%-20% of the total mass of the back coating layer 1, more preferably 8%-15%. Furthermore, to improve the lubricity of the back coating layer and reduce frictional damage to the print head during printing, a certain amount of solid and liquid lubricants, such as metal soaps, phosphate esters, silicone oils, and mold release agents, can be added to the back coating layer 1. The amount added is 10%-40% of the resin, preferably 20%-30%.

[0058] Furthermore, to address the issue of material buildup in the printhead and further improve the lubricity of the back coating, a certain amount of solid fillers such as silica, talc, and kaolin can be added to the back coating 1. The particle size should be selected as 300nm-5μm, preferably 1-4μm. Too large a particle size will affect the surface smoothness of the coating, while too small a particle size will fail to reduce friction between the printhead and the back coating.

[0059] The amount of solid filler added in the back coating 1 is 1%-5% of the resin mass, preferably 3%-5%.

[0060] To improve the color density of ribbon printing, the coating thickness of the back coating layer 1 can be reduced within a certain range. The color density gradually increases as the coating thickness decreases, but the heat resistance of the ribbon during printing needs to be considered. Therefore, the coating thickness of the back coating layer 1 is 0.2-1 μm, preferably 0.4-0.6 μm.

[0061] The method for preparing a sublimation ribbon with multiple anti-dye diffusion mechanisms of the present invention includes the preparation step of dye layer 6, specifically: A first dye layer coating solution and a second dye layer coating solution are prepared using organic solvents respectively; the first dye layer coating solution is coated on the base layer 3 and cured to obtain the first dye layer 4; then the second dye layer coating solution is coated on the first dye layer 4 and cured to obtain the second dye layer 5.

[0062] Preferably, the organic solvent is a methyl ethyl ketone (MEK)-toluene mixture, with a mass ratio of MEK to toluene of 1:1 to 1:3; in each layer, the mass of the organic solvent is 80%-95% of the total mass of that layer.

[0063] The preparation method of the present invention further includes the steps of applying a coating liquid of a primer layer 3 to one side of the substrate 2 and applying a coating liquid of a back coating layer 1 to the other side of the substrate 2.

[0064] Specifically, before directly applying the coating liquid of the primer layer 3 onto the substrate 2, the substrate 2 needs to be surface treated. Considering cost, corona discharge treatment is generally adopted to make the dyne value of the substrate 2 surface > 38.

[0065] The solvent used in the base coat 3 is isopropanol, with a content of 90%-98% of the total mass of the coating liquid, and the resin content is 2%-10% of the total mass of the coating liquid, preferably 3%-6%. The coating thickness is 0.1-0.5μm, preferably 0.1-0.3μm. If the coating thickness is too low or too high, there is a risk of printing ink fading.

[0066] The solvent used in the coating liquid of the back coating layer 1 is a mixed solvent of methyl ethyl ketone (MEK) and toluene, with a preferred ratio of 3:1 to 2:1, and the amount of solvent added is 80% to 90% of the total mass of the coating liquid.

[0067] To improve the uniformity of ribbon printing, some components of the back coating 1 need to be ground. Specifically, grinding the solid lubricant and solid granules can improve their distribution uniformity in the back coating 1, as well as the uniformity of the particle size of the granules.

[0068] Within a certain range, as the grinding time increases, the uniformity of the light color gradation of the ribbon printing will gradually improve, thereby reducing uneven color distribution and white spots; however, after grinding for a certain period of time, its uniformity will no longer change.

[0069] Preferably, zirconium beads with a particle size of 0.6 mm are added during grinding, the grinding speed is 1500 r / min, the air pump pressure is 0.2 MPa, and stirring is required during grinding to avoid uneven system or sedimentation.

[0070] Preferably, the grinding time is 30-120 min, and more preferably 40-60 min.

[0071] The effects of the present invention will be illustrated below through specific embodiments and comparative examples.

[0072] Example 1 like Figure 1 and 2 As shown, the substrate 2 in this embodiment uses a 4.3μm thick PET film manufactured by Anhui Tongai.

[0073] The composition of the base coating 3 in this embodiment is: 2 parts polyvinylpyrrolidone (industrial grade PVP K90, Guangdong Yuemei Chemical), 2 parts polyvinyl alcohol (Tianjin Damao Chemical), and 96 parts isopropanol. After preparing the above components into a coating liquid using an organic solvent, it is coated using a gravure coating machine, and the coating thickness is 0.2 μm.

[0074] In the dye layer 6 of this embodiment, both the first dye layer 4 and the second dye layer 5 have three colors: yellow, magenta and cyan, and the same color areas correspond in the two layers.

[0075] The first yellow layer 41 consists of: 2.5 parts polyurethane (901H Wanhua Chemical), 3.5 parts solvent yellow 2 (Henan Wokas Biotechnology), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are: 46.62 parts 2-butanone and 46.62 parts toluene. After being prepared as a coating solution, it is coated using a gravure coating machine to a coating thickness of 0.4 μm.

[0076] The first yellow layer 51 consists of: 3.5 parts polyurethane (901H Wanhua Chemical), 4.0 parts solvent yellow 2 (Henan Wokas Biotechnology), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are: 46.62 parts 2-butanone and 46.62 parts toluene. After preparation as a coating solution, it is coated using a gravure coating machine to a coating thickness of 0.3 μm.

[0077] The composition of the first magenta layer 42 is as follows: 2.8 parts polyurethane (901H Wanhua Chemical), 5.0 parts solvent red 24 (Sinopharm Chemical Reagent), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 45.92 parts 2-butanone and 45.92 parts toluene. After preparation as a coating solution, it is coated using a gravure coating machine to a coating thickness of 0.6 μm.

[0078] The second magenta layer 52 consists of 3.6 parts polyurethane (901H Wanhua Chemical), 4.4 parts solvent red 24 (Sinopharm Chemical Reagent), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 45.92 parts 2-butanone and 45.92 parts toluene. After preparation as a coating solution, it is coated using a gravure coating machine to a coating thickness of 0.5 μm.

[0079] The first cyan layer 43 consists of 2.5 parts polyurethane (901H Wanhua Chemical), 4.5 parts solvent blue 36 (Nanjing Kangmanlin Chemical Industry), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 45.93 parts 2-butanone and 45.93 parts toluene. After being prepared as a coating solution, it is applied using a gravure coating machine to a coating thickness of 0.8 μm.

[0080] The second cyan layer 53 consists of 3.2 parts polyurethane (901H Wanhua Chemical), 4.5 parts solvent blue 36 (Nanjing Kangmanlin Chemical Industry), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 45.93 parts 2-butanone and 45.93 parts toluene. After being prepared as a coating solution, it is coated using a gravure coating machine to a coating thickness of 0.5 μm.

[0081] The back coating 1 in this embodiment consists of 3 parts polyvinyl butyral (B265H-B Guangzhou Hongshang), 7 parts cellulose acetate butyrate (CAB393-3 Eastman Chemical), 2.5 parts isocyanate (WANNATE® MDI-50 Wanhua Chemical), 0.5 parts talc (LJ-320 Liangjiang Chemical), and 0.2 parts silicone oil (KF-6001 Shin-Etsu Silicone). The solvent used is 57.8 parts 2-butanone and 29 parts toluene. After preparation as a coating solution, it is applied using a gravure coating machine to a thickness of 0.5 μm. The coating is then ground using a sander for 40 minutes.

[0082] Example 2 The substrate 2, base coating 3, and back coating 1 in this embodiment are the same as in Example 1. The formulation of the dye layer 6 is also completely the same as in Example 1, and the coating process is as follows: The first yellow layer 41 is coated using a gravure coating machine with a coating thickness of 0.5 μm; the first yellow layer 51 is coated using a gravure coating machine with a coating thickness of 0.4 μm; the first magenta layer 42 is coated using a gravure coating machine with a coating thickness of 0.6 μm; the second magenta layer 52 is coated using a gravure coating machine with a coating thickness of 0.4 μm; the first cyan layer 43 is coated using a gravure coating machine with a coating thickness of 0.8 μm; and the second cyan layer 53 is coated using a gravure coating machine with a coating thickness of 0.4 μm.

[0083] Example 3 The substrate 2, base coating 3, and back coating 1 in this embodiment are the same as in Example 1. The formulation of the dye layer 6 is also completely the same as in Example 1, and the coating process is as follows: The first yellow layer 41 was coated using a gravure coating machine, with a coating thickness of 0.4 μm. The first yellow layer 51 was coated using a gravure coating machine, with a coating thickness of 0.2 μm. The first magenta layer 42 was coated using a gravure coating machine, with a coating thickness of 0.6 μm. The second magenta layer 52 was coated using a gravure coating machine, with a coating thickness of 0.3 μm. The first cyan layer 43 was coated using a gravure coating machine, with a coating thickness of 0.8 μm. The second cyan layer 53 was coated using a gravure coating machine, with a coating thickness of 0.3 μm.

[0084] Example 4 The substrate 2, base coating 3, and back coating 1 in this embodiment are the same as in Example 1. The coating thickness of the dye layer 6 is the same as in Example 1, and the formulations of the second dye layers 5 for each color are also the same as in Example 1. The formulations of the first dye layers 4 for each color are as follows: The first yellow layer 41 consists of 2.3 parts polyurethane (901H Wanhua Chemical), 3.2 parts solvent yellow 2 (Henan Wokas Biotechnology), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 46.62 parts 2-butanone and 46.62 parts toluene.

[0085] The first magenta layer 42 consists of: 2.7 parts polyurethane (901H Wanhua Chemical), 4.8 parts solvent red 24 (Sinopharm Chemical Reagent), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 45.92 parts 2-butanone and 45.92 parts toluene.

[0086] The first cyan layer 43 consists of 2.5 parts polyurethane (901H Wanhua Chemical), 5.0 parts solvent blue 36 (Nanjing Kangmanlin Chemical Industry), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 45.93 parts 2-butanone and 45.93 parts toluene.

[0087] Example 5 The substrate 2, base coating 3, and back coating 1 in this embodiment are the same as in Example 1. The coating thickness of the dye layer 6 is the same as in Example 1, and the formulation of the first dye layer 4 for each color is also the same as in Example 1. The formulation of the second dye layer 5 for each color is as follows: First yellow layer 51: Polyurethane (901H Wanhua Chemical) 3.7 parts, Solvent Yellow 2 (Henan Wokas Biotechnology) 3.4 parts, Octadecyl Erucamide (DY1558 Jiangxi Dongyuan) 0.13 parts, the solvents used were 2-Butanone 46.62 parts and Toluene 46.62 parts. Second magenta layer 52: Polyurethane (901H Wanhua Chemical) 3.2 parts, Solvent Red 24 (Sinopharm Chemical Reagent) 4.5 parts, Octadecyl Erucamide (DY1558 Jiangxi Dongyuan) 0.13 parts, the solvents used were 2-Butanone 45.92 parts and Toluene 45.92 parts. The second cyan layer 53 consists of: 3.2 parts polyurethane (901H Wanhua Chemical), 4.8 parts solvent blue 36 (Nanjing Kangmanlin Chemical Industry), and 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan). The solvents used are 45.93 parts 2-butanone and 45.93 parts toluene.

[0088] Comparative Example 1 The substrate 2, base coating 3, and back coating 1 of this comparative example are the same as those in Example 1, and the dye layer 6 formulation is as follows: Yellow: Polyurethane (901H Wanhua Chemical) 2.5 parts, Solvent Yellow 2 (Henan Wokas Biotechnology) 3.5 parts, Octadecyl Erucamide (DY1558 Jiangxi Dongyuan) 0.13 parts; solvents used: 2-Butanone 46.62 parts, Toluene 46.62 parts. Coating was performed using a gravure coating machine, with a coating thickness of 0.4 μm.

[0089] Magenta color: 2.8 parts polyurethane (901H Wanhua Chemical), 5.0 parts solvent red 24 (Sinopharm Chemical Reagent), 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan), and 45.92 parts 2-butanone and 45.92 parts toluene were used as solvents. Gravure coating was used, with a coating thickness of 0.6 μm.

[0090] Cyan: 2.5 parts polyurethane (901H Wanhua Chemical), 5.0 parts solvent blue 36 (Nanjing Kangmanlin Chemical Industry), 0.13 parts octadecyl erucamide (DY1558 Jiangxi Dongyuan), the solvents used are 45.93 parts 2-butanone and 45.93 parts toluene, coated using a gravure coating machine, with a coating thickness of 0.8μm.

[0091] Comparative Example 2 The substrate 2, base coating 3, and back coating 1 of this comparative example are the same as those in Example 1, and the coating thickness of the dye layer 6 is the same as that in Example 1. The formulation is as follows: Yellow: 4.5 parts polyurethane (901H Wanhua Chemical), 5.9 parts solvent yellow 2 (Henan Wokas Biotechnology), 0.02 parts silicone oil (KM-244F Shin-Etsu Silicone), and the solvents used are 44.5 parts 2-butanone and 44.5 parts toluene.

[0092] Magenta: 3.2 parts polyurethane (901H Wanhua Chemical), 5.5 parts solvent red 24 (Sinopharm Chemical Reagent), 0.03 parts silicone oil (KM-244F Shin-Etsu Silicone), and the solvents used are 45.92 parts 2-butanone and 45.92 parts toluene.

[0093] Cyan: 3.0 parts of polyurethane (901H Wanhua Chemical), 5.9 parts of solvent blue 24 (Sinopharm Chemical Reagent), 0.03 parts of silicone oil (KM-244F Shin-Etsu Silicone), and the solvents used are 45.93 parts of 2-butanone and 45.93 parts of toluene.

[0094] The performance of the sublimation ribbons of the above embodiments and comparative examples was tested. The specific test plan and results are as follows: (1) Color density test: DTP330 was used for printing, and STB values ​​were set to Y185, M200, C200, OC100. The color density of the printed product with OC overlay was tested using an X-Rite i1 PRO3 colorimeter. Data at levels 1, 9, and 16 were recorded. The test results are shown in Table 1.

[0095] Table 1 Color density test (2) Anti-diffusion performance test: Print the standard test pattern on DNP photographic paper, observe the edge of the printed lines with a microscope, and measure the dye diffusion width. Test conditions: temperature 23±2℃, relative humidity 50±5%, 10 measurement points were selected for each sample and the average value was taken. The test results are shown in Table 2.

[0096] Table 2 Anti-proliferation performance test (3) Curing time test: Record the time from the completion of coating to the stable performance of the product. When the highest color density fluctuation of three consecutive tests is less than ±0.1 and the average value of anti-diffusion performance is stable and meets the standard, the total time is the curing time. The test results are shown in Table 3.

[0097] Table 3. Curing Time Test (4) Dye migration test: The color material layer of the ribbon and the heat-resistant slip layer are stacked face to face, and after applying a pressure of 20 kg / cm2, they are stored in an environment of 40℃ and 90% RH for 96 hours. The color difference (ΔEab) of the heat-resistant slip layer before and after storage is measured using a spectrophotometer. The pass standard is ΔEab<10. The test results are shown in Table 4.

[0098] Table 4 Dye migration test (5) Background Contamination Prevention Test: Unused ribbons were stored at 50°C and 80% RH for 60 hours. Immediately after storage, test patterns were printed, and the chromaticity of the unprinted pure white areas was measured using a spectrophotometer. The color difference (ΔEab) was calculated by comparing the measured area with the sample printed before storage. The acceptable standard was ΔEab < 0.2. The test results are shown in Table 5.

[0099] Table 5 Background Pollution Prevention Test This invention achieves synergistic optimization of color density and anti-diffusion performance in sublimation ribbons through a double-layer dye structure. The test results of the above embodiments and comparative examples verify the effectiveness of this invention.

[0100] Examples 1-5 showed excellent performance in color density testing, with yellow reaching 1.98-2.02 for the 16th order, magenta reaching 1.99-2.08, and cyan reaching 2.01-2.08, significantly higher than Comparative Example 1 and Comparative Example 2, indicating that the bilayer structure has a significant effect in maintaining high color density.

[0101] Anti-diffusion performance tests showed that the average dye diffusion width of Example 1 was only 2.2 μm, Example 2 was further optimized to 1.9 μm, and Examples 3-5 were in the range of 2.3-2.8 μm, all of which were far superior to Comparative Example 1 and Comparative Example 2. This indicates that the dense polymer network formed by the second dye layering through the low dye-resin ratio did effectively construct a physical barrier, and Example 2 had the best effect due to the optimal thickness ratio.

[0102] The curing time test revealed that Examples 1, 2, 4, and 5 were all around 48 hours, Example 3 was shortened to 40 hours, while Comparative Example 1 of the single-layer structure required more than 96 hours, and Comparative Example 2 even exceeded 168 hours, indicating that the double-layer design accelerated the stabilization process of the system through gradient ratio control.

[0103] The dye migration test results showed that the ΔE*ab values ​​of Examples 1-5 were all between 2.0 and 3.5, reaching an excellent level, while Comparative Example 1 reached 16.5 and Comparative Example 2 reached 18.2, indicating severe migration and failing to meet the qualified standard of ΔEab<10. This result fully verified the ability of the low resin ratio second layer to inhibit longitudinal migration.

[0104] Background contamination tests showed that the color difference ΔEab of the unprinted pure white area in Examples 1, 2, and 4 was less than 0.2, which was considered excellent. Examples 3 and 5 were qualified between 0.2 and 0.3, while Comparative Examples 1 and 2 were unqualified because they were greater than 0.3. This indicates that the double-layer structure effectively avoids the problem of coloring in the unprinted area caused by the migration of dye to the back coating.

[0105] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A sublimation ribbon with multiple anti-dye diffusion mechanisms, characterized in that, The material includes a base coating layer (3) on which a dye layer (6) is provided; the dye layer (6) includes a first dye layer (4) and a second dye layer (5), wherein the first dye layer (4) is attached to the base coating layer (3) and the second dye layer (5) is attached to the first dye layer (4); in the first dye layer (4), the mass ratio of dye to resin is 1.5:1-2.4:1, and in the second dye layer (5), the mass ratio of dye to resin is 0.7:1-1.5:

1.

2. The sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 1, characterized in that, The resin in the first dye layer (4) is the first resin, and the glass transition temperature Tg of the first resin is greater than 70℃; the resin in the second dye layer (5) is the second resin, and the glass transition temperature Tg of the second resin is 50-65℃.

3. A sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 2, characterized in that, The first resin and the second resin are each independently selected from one or more of the following: polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methylcellulose, polyurethane, polycarbonate, polyester resin, etc.

4. A sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 2, characterized in that, The resin mass in each layer is 2%-15% of the total mass of each layer.

5. A sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 1, characterized in that, The first dye layer (4) and the second dye layer (5) each have multiple color regions, and each color region in the first dye layer (4) and the second dye layer (5) corresponds to another color region.

6. A sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 1, characterized in that, The first dye layer (4) and the second dye layer (5) also include a curing agent, which is an isocyanate compound.

7. A sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 1, characterized in that, The second dye layer (5) also contains solid filler, the mass of which is 0.2%-0.4% of the total amount of resin and dye in the layer.

8. A sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 1, characterized in that, The total thickness of the dye layer (6) is 0.5-1.2 μm, and the thickness of the first dye layer (4) accounts for 40%-60% of the total thickness.

9. A sublimation ribbon with multiple anti-dye diffusion mechanisms according to any one of claims 1-8, characterized in that, The resin in the base coating (3) is one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, methylcellulose, etc.; the base coating (3) also includes a molecular-level interface modifier, which is one or more of silane coupling agent, titanate coupling agent or zirconate aluminate coupling agent.

10. A method for preparing a thermal sublimation ribbon with multiple anti-dye diffusion mechanisms as described in any one of claims 1-9, characterized in that, In the preparation method, the preparation steps of the dye layer (6) are as follows: The first dye layer coating solution and the second dye layer coating solution are prepared by using organic solvents respectively; the first dye layer coating solution is coated on the base layer (3) and cured to obtain the first dye layer (4); the second dye layer coating solution is then coated on the first dye layer (4) and cured to obtain the second dye layer (5).

11. The method for preparing a sublimation ribbon with multiple anti-dye diffusion mechanisms according to claim 10, characterized in that, The organic solvent is a methyl ethyl ketone (MEK)-toluene mixture, with a mass ratio of MEK to toluene of 1:1 to 1:3; in each layer, the mass of the organic solvent is 80%-95% of the total mass of that layer.

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