Micro-embossed coating - LED pre-cure - EB cure coating and method of making

Abstract

The present application relates to the technical field of micro-recess coating precision coating, and particularly relates to a micro-recess coating-LED pre-curing-EB curing coating and a preparation method thereof. Coating slurry and a flexible substrate are pretreated to obtain the slurry and the substrate; the slurry is micro-recess coated on the surface of the substrate to form a uniform wet film, and a coated wet film substrate is obtained; the coated wet film substrate is subjected to low-temperature surface pre-curing by LED excimer, and a pre-cured substrate is obtained; the pre-cured substrate is subjected to EB accelerated curing in an inert atmosphere, and is wound to obtain a target micro-recess coating-LED pre-curing-EB curing coating. The method integrates micro-recess coating, LED excimer pre-curing and EB accelerated curing, ensures uniform coating and stable performance, and can meet the demand of high-end fields such as optical films, new energy diaphragms and other high-value-added products.

Description

Technical Field

[0001] This invention relates to the field of micro-recessed coating precision coating technology, specifically to a method for preparing a micro-recessed coating-LED pre-cured-EB cured coating. Background Technology

[0002] In the field of precision coating preparation, especially in the production of ultrathin coatings (1~50μm), coating uniformity, thorough curing, and substrate compatibility are core technical requirements. Existing coating preparation processes mainly suffer from the following pain points: Insufficient coating uniformity: Traditional coating methods (such as blade coating and comma coating) are difficult to achieve precise thickness control of ultrathin coatings, and defects such as streaks and edge thickening are prone to occur. While microgravure coating has the advantage of thin coating, the wet film is prone to sagging and edge shrinkage after single microgravure coating, which affects the final coating morphology.

[0003] Therefore, traditional technologies need to be addressed. Summary of the Invention

[0004] In view of this, the purpose of this invention is to at least partially solve one of the technical problems in the above-mentioned related technologies. To this end, this invention provides a method for preparing a micro-gravure coating-LED pre-curing-EB curing coating. This method integrates micro-gravure coating, LED excimer pre-curing and EB accelerated curing, ensuring uniform coating and stable performance, and can meet the needs of high-value-added products in high-end fields such as optical films and new energy separators.

[0005] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0006] In a first aspect, the present invention provides a method for preparing a micro-recessed coating-LED pre-curing-EB curing coating, comprising the following steps:

[0007] The coating slurry and flexible substrate are pretreated to obtain the slurry and substrate;

[0008] The slurry is micro-concave coated onto the surface of the substrate to form a uniform wet film, thereby obtaining a substrate coated with a wet film;

[0009] The substrate with the coated wet film is subjected to low-temperature surface pre-curing of LED excimer lasers to obtain a pre-cured substrate;

[0010] The pre-cured substrate is subjected to EB accelerated curing under an inert atmosphere, and then wound up to obtain the target micro-recessed LED pre-cured EB cured coating.

[0011] Compared with existing technologies, this invention overcomes the inherent limitations of existing single curing modes through an integrated process design that includes slurry and substrate pretreatment, microgravure coating, low-temperature pre-curing of LED excimer lasers, accelerated curing in an inert atmosphere (EB), and winding. Specifically, microgravure coating offers the advantage of thin coating, while LED excimer laser pre-curing enables low-temperature shaping. The inventors creatively combine microgravure coating and LED excimer laser pre-curing, and their combined use creates a synergistic effect, effectively solving the problems of easy sagging and edge shrinkage of wet films after single microgravure coating. At the same time, the deep cross-linking characteristics of EB accelerated curing compensate for the shortcomings of insufficient penetration depth and incomplete deep curing of single LED curing, as well as the coating deformation caused by the lack of a shaping step in single EB curing. It is worth mentioning that through LED excimer pre-curing and EB electron beam curing / adhesion / modification, the modulus, hardness, heat resistance, stability, chemical resistance, and weather resistance of the material itself are improved by 50%-200%, and the wear resistance, scratch resistance, and corrosion resistance of the coating are also significantly improved. Its surface hardness can reach 2H-9H, while maintaining zero VOC emissions.

[0012] Moreover, the method of the present invention can achieve high uniformity of the coating surface, with the left and right errors controlled within 3%. Ultra-thin coating can be achieved with extremely low viscosity coating liquid, and the coating layer can be as low as 0.5μm. At the same time, high-speed coating can be achieved, with a speed of more than 100m / min. It can meet the coating needs of various materials and different thicknesses, especially ultra-thin films of 15μm, such as PVC, PET, PP, etc.

[0013] It should be understood that before coating, matching parameters need to be retrieved from a preset process parameter template library according to the thickness of the coating to be prepared, the type of substrate (flexible / rigid) and the performance requirements (such as hardness, adhesion and weather resistance) for fine-tuning and adaptation; the process parameter template library includes microgravure coating parameters, LED excimer pre-curing parameters and EB accelerated curing parameters corresponding to different coating thicknesses and substrate types.

[0014] Further, the coating slurry comprises: 30-50 parts of SD6361, 0.5-1.2 parts of Tego 4053, 4-6 parts of E-1011, 5-10 parts of Al2O3 / TM, 15-20 parts of HDDA, 0.1-0.5 parts of R972, 0.1-0.5 parts of Tego 410, 0.1-0.5 parts of Tego 2700, 0.1-0.5 parts of Tego 920, 0.05-0.2 parts of TPO, 3-6 parts of MBF, 8-12 parts of SD1363, 8-12 parts of SD7832, 8-12 parts of HDDA, and 15-20 parts of TMCHA.

[0015] Among them, SD6361 is a functional polyurethane acrylate resin with fast curing speed, used in excimer / UV coatings to provide film toughness and surface feel; Tego 4053 is Evonik's surface control additive, used to improve substrate wettability and leveling; E-1011 is Tosoh Nipsil®. E-1011 matting agent (precipitated silica), fine-particle size, high transparency, used for matting in thin-coat systems, does not affect the base color; Al2O3 / TM is high-purity nano-alumina (Daming Chemical TM series), used as a wear-resistant / hardening filler to improve coating hardness, wear resistance, and high-temperature resistance; HDDA is 1,6-hexanediol diacrylate, a bifunctional active diluent that reduces viscosity and improves adhesion and curing speed; R972 is Degussa AEROSIL® R972 hydrophobic fumed silica, thickening, thixotropic, anti-settling, and prevents pigment delamination; Tego410 is TEGO® Glide410 leveling agent, a polyether siloxane copolymer that prevents pinholes, increases smoothness, and improves surface flatness; Tego2700 is TEGO® Rad 2700 radiation curing aid contains acrylic double bonds, participates in crosslinking, and provides anti-blocking, anti-graffiti, and slip-resistant effects; Tego920 is TEGO® Airex920 silicone-free defoamer, highly efficient at breaking and defoaming, suitable for UV varnishes / paints, and does not affect recoating; TPO is photoinitiator TPO (2,4,6-trimethylbenzoyl diphenylphosphine oxide), a type I high-efficiency photoinitiator with a broad absorption peak, suitable for thick film deep curing and low yellowing requirements; MBF is photoinitiator MBF (methyl benzoylformate), which works in conjunction with TPO. The compounding process improves curing efficiency; SD1363 is a high-functionality polyurethane acrylate resin, which can improve coating hardness, gloss and scratch resistance; SD7832 is a polyurethane acrylate resin, which can enhance adhesion and weather resistance; HDDA is 1,6-hexanediol diacrylate, which, as a bifunctional reactive diluent, can reduce viscosity, improve adhesion and curing speed; TMCHA is 3,3,5-trimethylcyclohexyl acrylate, which, as a monofunctional UV monomer, has low odor, good flexibility and improves film stretchability and substrate adhesion.

[0016] Furthermore, the substrate includes PET film or polypropylene nonwoven fabric.

[0017] Furthermore, in the step of pretreating the coating slurry and the flexible substrate, the coating slurry is subjected to viscosity testing, solid content calibration, and vacuum degassing treatment.

[0018] It should be understood that during the above-mentioned vacuum degassing process, if the viscosity is detected as low, the pressure during vacuum degassing is -0.08 to -0.09 MPa; if the viscosity is detected as medium to high, the pressure during vacuum degassing is -0.095 to -0.098 MPa (the limit can reach -0.1 MPa).

[0019] Compared with existing technologies, this invention avoids defects such as pinholes and uneven thickness caused by bubbles and viscosity fluctuations in the coating slurry by performing viscosity testing, solid content calibration and vacuum degassing treatment on the coating slurry. This broadens the applicability of the process and provides a prerequisite guarantee for the overall stability of the coating quality.

[0020] Furthermore, in the step of micro-grooving the slurry onto the surface of the substrate to form a uniform wet film, the micro-grooving roller cavity depth is 5μm~50μm, the line count is 100LPI~600LPI, the coating pressure is 0.1MPa~0.5MPa, the substrate speed is 5m / min~30m / min, the coating gap is 5μm~20μm, and the coating gap deviation is ≤±2μm.

[0021] Compared with existing technologies, this invention solves the problems of difficult thickness control and large thickness fluctuations in single micro-grooving coatings by standardizing key parameters such as micro-grooving roller cell depth, line count, and coating pressure, and strictly controlling the coating gap deviation to ≤±2μm. It achieves precise coating of ultra-thin wet films of 1~50μm. At the same time, the standardization of parameters reduces the complexity of debugging and material waste caused by parameter ambiguity in existing technologies, providing reliable parameter support for rapid order changeover in small-batch, multi-variety production, and directly ensuring the uniformity of coating thickness.

[0022] Furthermore, in the step of performing low-temperature surface pre-curing of the substrate with the coated wet film for LED excimer lasers, the wavelength is 222nm~308nm, the irradiation intensity is 50mW / cm²~200mW / cm², the curing distance is 10mm~30mm, and the surface temperature of the substrate with the coated wet film is ≤40℃.

[0023] Compared with existing technologies, this invention achieves low-temperature surface pre-curing by limiting the core parameters of LED excimer pre-curing wavelength range, irradiation intensity, curing distance, and substrate surface temperature ≤40℃. This avoids the thermal shrinkage problem of heat-sensitive flexible substrates and can quickly lock the wet film morphology, preventing wet film sagging and edge shrinkage after micro-concave coating. It provides a stable coating foundation for subsequent EB deep curing and makes up for the shortcoming of poor compatibility between single LED curing and flexible substrates.

[0024] Furthermore, in the step of accelerating the curing of the pre-cured substrate under an inert atmosphere using EB, the accelerating voltage is 80kV~200kV, the curing dose is 3kGy~10kGy, the curing distance is 50mm~150mm, and the oxygen content is ≤50ppm.

[0025] Compared with existing technologies, this invention optimizes the acceleration voltage, curing dosage, and curing distance parameters of EB accelerated curing, and controls the oxygen content to ≤50ppm, thereby achieving deep and thorough cross-linking of the coating. It solves the defects of single EB curing without a shaping step, incomplete curing, and yellowing of the coating due to excessive oxygen content. It significantly improves the hardness, weather resistance, and wear resistance of the coating, while ensuring curing uniformity and avoiding the problems of local over- or under-curing.

[0026] Furthermore, the inert atmosphere includes a nitrogen atmosphere.

[0027] Compared with existing technologies, this invention explicitly includes nitrogen in the inert atmosphere, which can continuously play the core role of isolating oxygen, further ensuring the thoroughness of EB curing and improving the reliability of the process and the stability of coating performance.

[0028] Furthermore, the micro-gravure coating is performed in the micro-gravure coating unit; the LED excimer curing is performed in the LED excimer curing unit; and the EB accelerated curing is performed in the EB accelerated curing unit.

[0029] Compared with existing technologies, this invention sets up microgravure coating, LED excimer curing, and EB accelerated curing in separate units, which facilitates precise parameter adjustment and equipment maintenance for each process step. It avoids the problems of poor parameter coordination and mutual interference caused by the dispersion of existing combined process equipment, improves process stability, and ensures the consistency of coating quality.

[0030] Furthermore, the microgravure coating unit, the LED excimer curing unit, and the EB accelerated curing unit operate synchronously through a linkage conveying unit, with a linear speed deviation of ≤±1% and a correction accuracy of ±0.1mm for the linkage conveying unit; the transmission interval between the microgravure coating unit and the LED excimer curing unit is ≤500mm; and the transmission interval between the LED excimer curing unit and the EB accelerated curing unit is 1m~3m.

[0031] Compared with existing technologies, this invention achieves synchronous operation of each unit through a linkage conveying unit, controlling the linear speed deviation to ≤±1% and the correction accuracy to ±0.1mm. This solves the problems of inconsistent unit speeds and substrate offset caused by coating stretching and edge defects in existing processes. At the same time, the reasonable setting of the transmission interval ensures rapid pre-curing of the wet film and avoids secondary deformation, improving the continuity and stability of the process and safeguarding the coating quality.

[0032] Furthermore, the coating thickness of the micro-recessed coating-LED pre-cured-EB cured coating is 1μm~50μm, the coating thickness uniformity is ≤±3%, the coating surface hardness is ≥1H, and the adhesion is ≥4B.

[0033] Compared with existing technologies, this invention clearly defines the core performance indicators of coating thickness, uniformity, surface hardness, and adhesion, solving the shortcomings of existing technologies such as large coating thickness deviation, insufficient hardness, and poor adhesion. It meets the stringent requirements of ultra-thin precision coatings, reduces the product defect rate, and provides clear quality judgment standards for small-batch, multi-order production, ensuring the consistency of product quality.

[0034] Secondly, the present invention provides the application of the coating prepared by the above-mentioned preparation method in the preparation of optical films or new energy separators.

[0035] Compared with existing technologies, this invention clearly defines that the coating can be applied to the preparation of optical films and new energy separators, solving the problem that existing processes cannot meet the needs of high value-added products. In the application scenario of optical films, the high uniformity and non-yellowing characteristics of the coating meet the stringent requirements of optical films for appearance and performance. In the application scenario of new energy separators, the high adhesion and puncture resistance of the coating meet the stability and safety requirements of the separator, significantly expanding the application range of precision coatings and enhancing the industrialization value of the process.

[0036] In summary, the technical effects achieved by this invention are as follows:

[0037] This invention is the first to integrate micro-concave technology, LED technology, excimer laser technology, and electron accelerator technology to prepare precision coatings. It can achieve high uniformity of the coating surface, with the left-right error controlled within 3%. Ultra-thin coatings can be achieved with extremely low viscosity coating liquid, with coating layers as thin as 0.5 μm. At the same time, high-speed coating can be achieved, with speeds reaching over 100 m / min. It can meet the coating requirements of various materials and different thicknesses, especially ultra-thin films of 15 micrometers, such as PVC, PET, PP, etc.

[0038] The combination of multiple functional light sources and drying processes can achieve different surface effects. LED-assisted surface pre-curing can be controlled to 5%-20%, while excimer laser-assisted surface texture formation allows for the creation of various textures on the coating surface by adjusting the angle and power of the excimer light source. Further curing / adhesion / modification using EB electron beams improves the material's modulus, hardness, heat resistance, stability, chemical resistance, and weather resistance by 50%-200%. It also significantly enhances the coating's wear resistance, scratch resistance, and corrosion resistance, achieving a surface hardness of 2H-9H. Simultaneously, it maintains zero VOC emissions. Attached Figure Description

[0039] Appendix Figure 1 This is a schematic diagram of the coating device of the present invention. Detailed Implementation

[0040] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0041] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges or individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0042] Unless otherwise specified, the term "comprising" as used in this invention can be either open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0043] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0044] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0045] The inventors of this invention discovered in their previous research that single-LED curing suffers from insufficient penetration depth and incomplete deep curing, resulting in poor coating adhesion and weather resistance. While single-EB curing can achieve complete curing, the wet film lacks a shaping step before curing, making it susceptible to coating deformation due to tension fluctuations during transport. Furthermore, high-energy electron beams can easily cause thermal shrinkage in heat-sensitive flexible substrates. Moreover, existing combined processes are mostly "coating-single-curing" models, involving complex parameter adjustments. When changing orders, the entire set of process parameters needs to be re-optimized, resulting in long adjustment times, significant material waste, and difficulty in adapting to the production needs of small batches and diverse product varieties. Coatings prepared by existing processes are prone to problems such as yellowing, pinholes, and insufficient hardness, especially in fields with stringent requirements for appearance and performance, such as optical films, making it difficult to meet the needs of high-value-added products.

[0046] To solve the above problems, the present invention is implemented as follows:

[0047] In a first aspect, embodiments of the present invention provide a method for preparing a micro-recessed coating-LED pre-curing-EB curing coating, comprising the following processes:

[0048] The coating slurry and flexible substrate are pretreated to obtain the slurry and substrate;

[0049] The slurry is micro-concave coated onto the surface of the substrate using a coating apparatus to form a uniform wet film, thereby obtaining a substrate with a coated wet film; the model of the coating apparatus is listed below. Figure 1 .

[0050] The substrate with the coated wet film is subjected to low-temperature surface pre-curing of LED excimer lasers to obtain a pre-cured substrate;

[0051] The pre-cured substrate is subjected to EB accelerated curing under an inert atmosphere, and then wound up to obtain the target micro-recessed LED pre-cured EB cured coating.

[0052] In the above technical solution, the present invention overcomes the inherent limitations of existing single curing modes by integrating the process design of slurry and substrate pretreatment, microgravure coating, low-temperature pre-curing of LED excimer lasers, accelerated curing in an inert atmosphere (EB), and winding. Specifically, microgravure coating has the advantage of thin coating, and LED excimer laser pre-curing can achieve low-temperature shaping. The inventors have creatively combined microgravure coating and LED excimer laser pre-curing, and the two work together to form a synergistic effect, effectively solving the problems of easy sagging and edge shrinkage of wet film after single microgravure coating. At the same time, the deep cross-linking characteristics of EB accelerated curing make up for the shortcomings of insufficient penetration depth and incomplete deep curing of single LED curing, as well as the coating deformation caused by the lack of a shaping step in single EB curing. It is worth mentioning that through LED excimer pre-curing and EB electron beam curing / adhesion / modification, the modulus, hardness, heat resistance, stability, chemical resistance, and weather resistance of the material itself are improved by 50%-200%, and the wear resistance, scratch resistance, and corrosion resistance of the coating are also significantly improved. Its surface hardness can reach 2H-9H, while maintaining zero VOC emissions.

[0053] Moreover, the method of the present invention can achieve high uniformity of the coating surface, with the left and right errors controlled within 3%. Ultra-thin coating can be achieved with extremely low viscosity coating liquid, and the coating layer can be as low as 0.5μm. At the same time, high-speed coating can be achieved, with a speed of more than 100m / min. It can meet the coating needs of various materials and different thicknesses, especially ultra-thin films of 15μm, such as PVC, PET, PP, etc.

[0054] It should be understood that before coating, matching parameters need to be retrieved from a preset process parameter template library according to the thickness of the coating to be prepared, the type of substrate (flexible / rigid) and the performance requirements (such as hardness, adhesion and weather resistance) for fine-tuning and adaptation; the process parameter template library includes microgravure coating parameters, LED excimer pre-curing parameters and EB accelerated curing parameters corresponding to different coating thicknesses and substrate types.

[0055] In some embodiments, the coating slurry includes: 30-50 parts of SD6361, 0.5-1.2 parts of Tego4053, 4-6 parts of E-1011, 5-10 parts of Al2O3 / TM, 15-20 parts of HDDA, 0.1-0.5 parts of R972, 0.1-0.5 parts of Tego 410, 0.1-0.5 parts of Tego2700, 0.1-0.5 parts of Tego 920, 0.05-0.2 parts of TPO, 3-6 parts of MBF, 8-12 parts of SD1363, 8-12 parts of SD7832, 8-12 parts of HDDA, and 15-20 parts of TMCHA.

[0056] For example, the coating paste includes: 30 parts SD6361, 0.5 parts Tego4053, 15 parts E-101, 5 parts Al2O3 / TM, 15 parts HDDA, 0.1 parts R972, 0.1 parts Tego 410, 0.1 parts Tego 2700, 0.1 parts Tego 920, 0.05 parts TPO, 3 parts MBF, 8 parts SD1363, 8 parts SD7832, 8 parts HDDA, and 15 parts TMCHA.

[0057] For example, the coating paste includes: 50 parts SD6361, 1.2 parts Tego4053, 6 parts E-1011, 10 parts Al2O3 / TM, 20 parts HDDA, 0.5 parts R972, 0.5 parts Tego 410, 0.5 parts Tego 2700, 0.3 parts Tego 920, 0.2 parts TPO, 6 parts MBF, 12 parts SD1363, 12 parts SD7832, 12 parts HDDA, and 20 parts TMCHA.

[0058] For example, the coating paste includes: 40 parts SD6361, 1 part Tego4053, 4 parts E-1011, 6 parts Al2O3 / TM, 16 parts HDDA, 0.2 parts R972, 0.3 parts Tego 410, 0.5 parts Tego 2700, 0.2 parts Tego 920, 0.1 parts TPO, 5 parts MBF, 10 parts SD1363, 10 parts SD7832, 10 parts HDDA, and 17 parts TMCHA.

[0059] Among them, SD6361 is a functional polyurethane acrylate resin with fast curing speed, used in excimer / UV coatings to provide film toughness and surface feel; Tego 4053 is Evonik's surface control additive, used to improve substrate wettability and leveling; E-1011 is Tosoh Nipsil®. E-1011 matting agent (precipitated silica), fine-particle size, high transparency, used for matting in thin-coat systems, does not affect the base color; Al2O3 / TM is high-purity nano-alumina (Daming Chemical TM series), used as a wear-resistant / hardening filler to improve coating hardness, wear resistance, and high-temperature resistance; HDDA is 1,6-hexanediol diacrylate, a bifunctional active diluent that reduces viscosity and improves adhesion and curing speed; R972 is Degussa AEROSIL® R972 hydrophobic fumed silica, with thickening, thixotropic, and anti-settling effects, preventing pigment delamination; Tego410 is TEGO® Glide410 leveling agent, a polyether siloxane copolymer that prevents pinholes, increases smoothness, and improves surface flatness; Tego2700 is TEGO® Rad 2700 radiation curing aid contains acrylic double bonds, participates in crosslinking, and provides anti-blocking, anti-graffiti, and slip-resistant effects; Tego920 is TEGO® Airex920 silicone-free defoamer, highly efficient at breaking and defoaming, suitable for UV varnishes / paints, and does not affect recoating; TPO is photoinitiator TPO (2,4,6-trimethylbenzoyl diphenylphosphine oxide), a type I high-efficiency photoinitiator with a broad absorption peak, suitable for thick film deep curing and low yellowing requirements; MBF is photoinitiator MBF (methyl benzoylformate), which works in conjunction with TPO. The compounding process improves curing efficiency; SD1363 is a high-functionality polyurethane acrylate resin, which can improve coating hardness, gloss and scratch resistance; SD7832 is a polyurethane acrylate resin, which can enhance adhesion and weather resistance; HDDA is 1,6-hexanediol diacrylate, which, as a bifunctional reactive diluent, can reduce viscosity, improve adhesion and curing speed; TMCHA is 3,3,5-trimethylcyclohexyl acrylate, which, as a monofunctional UV monomer, has low odor, good flexibility and improves film stretchability and substrate adhesion.

[0060] The substrate includes PET film or polypropylene (PP) film;

[0061] In the step of pretreating the coating slurry and the flexible substrate, the coating slurry is subjected to viscosity testing, solid content calibration and vacuum degassing treatment.

[0062] It should be understood that during the above-mentioned vacuum degassing process, if the viscosity is detected as low, the pressure during vacuum degassing is -0.08 to -0.09 MPa; if the viscosity is detected as medium to high, the pressure during vacuum degassing is -0.095 to -0.098 MPa (the limit can reach -0.1 MPa).

[0063] The above technical solution avoids defects such as pinholes and uneven thickness caused by bubbles and viscosity fluctuations in the coating slurry by performing viscosity testing, solid content calibration, and vacuum degassing treatment on the coating slurry. At the same time, plasma cleaning and activation treatment on the flexible substrate significantly improves the adhesion between the substrate and the coating. Combined with well-suited flexible substrates such as PET film and polypropylene nonwoven fabric, it effectively solves the pain points of poor substrate-coating compatibility and insufficient adhesion in the existing process, broadens the application scope of the process, and provides a prerequisite guarantee for the overall stability of the coating quality.

[0064] Furthermore, in the step of micro-grooving the slurry onto the surface of the substrate to form a uniform wet film, the micro-grooving roller cavity depth is 5μm~50μm, the line count is 100LPI~600LPI, the coating pressure is 0.1MPa~0.5MPa, the substrate speed is 5m / min~30m / min, the coating gap is 5μm~20μm, and the coating gap deviation is ≤±2μm.

[0065] For example, the depth of the micro-concave roller mesh can be specifically selected as a range of values ​​consisting of 5μm, 15μm, 35μm, 50μm, or any point value, preferably 15μm~35μm.

[0066] For example, the line count can be specifically selected as a range of values ​​consisting of 100 LPI, 200 LPI, 400 LPI, 600 LPI or any point value, preferably 200 LPI to 400 LPI.

[0067] For example, the coating pressure can be specifically selected as a range of values ​​consisting of 0.1MPa, 0.2MPa, 0.3MPa, 0.5MPa or any point value, preferably 0.2MPa to 0.3MPa.

[0068] For example, the substrate speed can be specifically selected as a range of values ​​consisting of 5 m / min, 10 m / min, 15 m / min, 30 m / min or any point value, preferably 10 m / min to 15 m / min.

[0069] For example, the coating gap can be specifically selected as a range of values ​​consisting of 5μm, 12μm, 20μm or any point value, preferably 5μm~12μm.

[0070] The above technical solution solves the problems of difficult thickness control and large thickness fluctuation of single micro-grooving coating by standardizing key parameters such as micro-grooving roller cell depth, line count, and coating pressure, and strictly controlling the coating gap deviation to ≤±2μm. It achieves precise coating of ultra-thin wet films of 1~50μm. At the same time, the standardization of parameters reduces the complexity of debugging and material waste caused by parameter ambiguity in the existing technology, and provides reliable parameter support for rapid order changeover in small-batch, multi-variety production, directly ensuring the uniformity of coating thickness.

[0071] In some embodiments, the step of performing low-temperature surface pre-curing of the substrate with coated wet film for LED excimer lasers is carried out with a wavelength of 222nm~308nm, an irradiation intensity of 50mW / cm²~200mW / cm², a curing distance of 10mm~30mm, and a substrate surface temperature of ≤40℃.

[0072] For example, the wavelength can be specifically selected as 222nm, 260nm or 308nm.

[0073] For example, the irradiation intensity can be specifically selected as a range of values ​​consisting of 50mW / cm², 120mW / cm², 180mW / cm², 200mW / cm², or any point value, preferably 120mW / cm² to 180mW / cm².

[0074] For example, the curing distance can be specifically selected as 10mm, 20mm, or 30mm.

[0075] The above technical solution achieves low-temperature surface pre-curing by limiting the core parameters of LED excimer pre-curing wavelength range, irradiation intensity, curing distance, and substrate surface temperature ≤40℃. This avoids the thermal shrinkage problem of heat-sensitive flexible substrates and can quickly lock the wet film morphology, preventing wet film sagging and edge shrinkage after micro-concave coating. It provides a stable coating foundation for subsequent EB deep curing and makes up for the shortcoming of poor compatibility between single LED curing and flexible substrates.

[0076] In some embodiments, the step of accelerating the curing of the pre-cured substrate under an inert atmosphere using EB is characterized by an accelerating voltage of 80kV to 200kV, a curing dose of 3kGy to 10kGy, a curing distance of 50mm to 150mm, and an oxygen content of ≤50ppm.

[0077] For example, the accelerating voltage is 80kV, 120kV, 180kV or 200kV.

[0078] For example, the curing dose can be specifically selected as 3kGy, 5kGy, 8kGy or 10kGy.

[0079] The above technical solution optimizes the acceleration voltage, curing dosage, and curing distance parameters of EB accelerated curing, and controls the oxygen content to ≤50ppm, thereby achieving deep and thorough cross-linking of the coating. It solves the defects of single EB curing without a shaping step, incomplete curing, and yellowing of the coating due to excessive oxygen content. It significantly improves the hardness, weather resistance, and wear resistance of the coating, while ensuring curing uniformity and avoiding the problems of local over- or under-curing.

[0080] In some embodiments, the inert atmosphere includes a nitrogen atmosphere.

[0081] In some of these embodiments, the microgravure coating is performed in a microgravure coating unit; the LED excimer curing is performed in an LED excimer curing unit; and the EB accelerated curing is performed in an EB accelerated curing unit.

[0082] The above technical solution sets up microgravure coating, LED excimer curing, and EB accelerated curing in independent units, which facilitates precise adjustment of parameters and equipment maintenance in each process step. It avoids the problems of poor parameter coordination and mutual interference caused by the dispersion of existing combined process equipment, improves process stability, and ensures the consistency of coating quality.

[0083] In some embodiments, the microgravure coating unit, the LED excimer curing unit, and the EB accelerated curing unit operate synchronously through a linkage conveying unit, with a linear speed deviation of ≤±1% and a correction accuracy of ±0.1mm for the linkage conveying unit; the transmission interval between the microgravure coating unit and the LED excimer curing unit is ≤500mm; and the transmission interval between the LED excimer curing unit and the EB accelerated curing unit is 1m~3m.

[0084] The above technical solution achieves synchronous operation of each unit through a linkage conveying unit, controlling the linear speed deviation to ≤±1% and the correction accuracy to ±0.1mm. This solves the problems of inconsistent unit speeds and substrate offset caused by coating stretching and edge defects in existing processes. At the same time, the reasonable setting of the transmission interval ensures rapid pre-curing of the wet film and avoids secondary deformation, improving the continuity and stability of the process and safeguarding the coating quality.

[0085] In some embodiments, the coating thickness of the microgravure coating-LED pre-curing-EB curing coating is 1μm~50μm, the coating thickness uniformity is ≤±3%, the coating surface hardness is ≥1H, and the adhesion is ≥4B.

[0086] The above technical solution clearly defines the core performance indicators of coating thickness, uniformity, surface hardness and adhesion, solves the shortcomings of existing technologies such as large coating thickness deviation, insufficient hardness and poor adhesion, meets the stringent requirements of ultra-thin precision coatings, reduces the product defect rate, and provides clear quality judgment standards for small-batch, multi-order production, ensuring the consistency of product quality.

[0087] Secondly, embodiments of the present invention provide the application of the coating prepared by the above-described preparation method in the preparation of optical films or new energy separators.

[0088] The above technical solution clearly states that the coating can be applied to the preparation of optical films and new energy membranes, solving the problem that existing processes cannot meet the needs of high value-added products. In the application scenario of optical films, the high uniformity and non-yellowing characteristics of the coating meet the stringent requirements of optical films for appearance and performance. In the application scenario of new energy membranes, the high adhesion and puncture resistance of the coating meet the stability and safety requirements of the membrane, significantly expanding the application range of precision coatings and enhancing the industrialization value of the process.

[0089] Example 1: Preparation of Precision Coating for Optical Films

[0090] In this embodiment, an optical film coating with a thickness of 10 μm is prepared using a PET film as the substrate. The specific steps are as follows:

[0091] S1. Retrieve the parameters corresponding to "10μm optical film coating" from the parameter template library, and after fine-tuning, determine: micro-groove roller cell depth 15μm, line count 400LPI, coating pressure 0.2MPa, substrate speed 15m / min; LED excimer wave 308nm, irradiance 120mW / cm². 2 The curing distance is 20mm; the EB accelerating voltage is 120kV, the curing dose is 5kGy, the curing distance is 50mm, and the oxygen content is controlled to be ≤30ppm.

[0092] S2. Adjust the viscosity of the coating slurry to 150 mPa·s, measure it with a No. 2 Zein cup, the viscosity is 45-60 s, after calibrating the solid content, perform vacuum degassing to obtain the slurry;

[0093] The coating slurry includes: 30 parts SD6361, 0.5 parts Tego4053, 15 parts E-101, 5 parts Al2O3 / TM, 15 parts HDDA, 0.1 parts R972, 0.1 parts Tego 410, 0.1 parts Tego 2700, 0.1 parts Tego 920, 0.05 parts TPO, 3 parts MBF, 8 parts SD1363, 8 parts SD7832, 8 parts HDDA, and 15 parts TMCHA; the pressure during vacuum degassing is -0.08 MPa.

[0094] S3. Feed the slurry into the micro-groove coating unit and coat it according to the set parameters to form a 10μm wet film. The coating gap is calibrated to 12μm using a feeler gauge.

[0095] S4. After wet film coating, the substrate enters the LED excimer curing unit through a 300mm transfer interval for low-temperature pre-curing, with the substrate surface temperature controlled at 35℃.

[0096] S5. The pre-cured substrate enters the EB accelerated curing unit through a 2m transfer interval and completes deep curing under nitrogen protection.

[0097] S6. The online film thickness gauge monitors the coating thickness as 10±0.3μm. The surface hardness is 2H and the adhesion is 5B. There are no yellowing or pinhole defects. After passing the test, the coating is rolled up.

[0098] The optical film coating prepared in this embodiment has excellent uniformity, light transmittance ≥92%, and after 1000h of weather resistance testing (xenon arc aging test according to GB / T16422.2-2022), the color difference ΔE ≤1.0, indicating stable performance.

[0099] Example 2: Preparation of New Energy Membrane Coating

[0100] This embodiment prepares a new energy membrane coating with a thickness of 30 μm. The substrate is polypropylene nonwoven fabric. The specific steps are as follows:

[0101] S1 retrieves the parameters for "30μm diaphragm coating" from the parameter template library and adjusts them to determine the following: micro-groove roller cell depth 35μm, line count 200LPI, coating pressure 0.3MPa, substrate speed 10m / min; LED excimer wavelength 222 nm, irradiance 180mW / cm², curing distance 10mm; EB accelerating voltage 180kV, curing dose 8kGy, curing distance 150mm, oxygen content controlled ≤20ppm.

[0102] S2. The viscosity of the slurry was adjusted to 350 mPa·s, and the solid content was calibrated before vacuum degassing. The polypropylene nonwoven fabric was then cleaned and activated by plasma to obtain the slurry.

[0103] The coating slurry includes: 50 parts SD6361, 1.2 parts Tego4053, 16 parts E-1011, 10 parts Al2O3 / TM, 20 parts HDDA, 0.5 parts R972, 0.5 parts Tego 410, 0.5 parts Tego 2700, 0.3 parts Tego 920, 0.2 parts TPO, 6 parts MBF, 12 parts SD1363, 12 parts SD7832, 12 parts HDDA, and 20 parts TMCHA.

[0104] The pressure during vacuum degassing is -0.095 MPa;

[0105] S3. Feed the slurry into the micro-gravure coating unit and coat it according to the set parameters. The coating gap is calibrated to 20μm by a feeler gauge to form a 30μm wet film.

[0106] S4. After wet film coating, the substrate enters the LED excimer curing unit through a 400mm transfer interval, and the surface temperature of the substrate is controlled at 38℃ to complete the pre-curing.

[0107] S5. The pre-cured substrate enters the EB accelerated curing unit through a 2m transfer interval, and completes deep curing under nitrogen protection.

[0108] S6. Online film thickness gauge monitors coating thickness. Coating thickness is 30±0.9μm, surface hardness is 1.5H, adhesion is 4B, and puncture resistance is ≥15N, meeting the requirements for use in new energy separators.

[0109] The optical film coating prepared in this embodiment has excellent uniformity, light transmittance ≥95%, and after 1000h of weather resistance testing (xenon arc aging test according to GB / T16422.2-2022), the color difference ΔE ≤2.0, indicating stable performance.

[0110] Example 3: Preparation of New Energy Membrane Coating

[0111] This embodiment prepares a new energy membrane coating with a thickness of 20 μm. The substrate is polypropylene nonwoven fabric. The specific steps are as follows:

[0112] S1 retrieves the parameters for "20μm diaphragm coating" from the parameter template library, and after adjustment, determines the following: micro-groove roller cell depth 5μm, line count 100LPI, coating pressure 0.1MPa, substrate speed 5m / min; LED excimer wavelength 308nm, irradiation intensity 50mW / cm², curing distance 30mm; EB accelerating voltage 80kV, curing dose 3kGy, curing distance 100mm, oxygen content control ≤50ppm.

[0113] S2. The viscosity of the slurry is adjusted to 350 mPa·s, and after the solid content is calibrated, vacuum degassing is performed to obtain the slurry.

[0114] The coating paste includes: 40 parts SD6361, 1 part Tego4053, 4 parts E-1011, 6 parts Al2O3 / TM, 16 parts HDDA, 0.2 parts R972, 0.3 parts Tego 410, 0.5 parts Tego 2700, 0.2 parts Tego 920, 0.1 parts TPO, 5 parts MBF, 10 parts SD1363, 10 parts SD7832, 10 parts HDDA, and 17 parts TMCHA;

[0115] The pressure during vacuum degassing is -0.098 MPa;

[0116] S3. Feed the slurry into the micro-gravure coating unit and coat it according to the set parameters. The coating gap is calibrated to 5μm by a feeler gauge to form a 30μm wet film.

[0117] S4. After wet film coating, the substrate enters the LED excimer curing unit through a 400mm transfer interval, and the surface temperature of the substrate is controlled at 38℃ to complete the pre-curing.

[0118] S5. The pre-cured substrate enters the EB accelerated curing unit through a 2m transfer interval, and completes deep curing under nitrogen protection.

[0119] S6. Online film thickness gauge monitors coating thickness. Coating thickness (5) μm, surface hardness (2) H, puncture resistance ≥ (1) N, meeting the requirements for use of new energy membranes.

[0120] The optical film coating prepared in this embodiment has excellent uniformity, light transmittance ≥95%, and after 1000h of weather resistance testing (xenon arc aging test according to GB / T16422.2-2022), the color difference ΔE ≤2.0, indicating stable performance.

[0121] Example 4: Preparation of Precision Coating for Optical Films

[0122] In this embodiment, an optical film coating with a thickness of 5 μm is prepared using a PET film as the substrate. The specific steps are as follows:

[0123] S1. Retrieve the parameters corresponding to "5μm optical film coating" from the parameter template library, and after fine-tuning, determine: micro-groove roller cell depth 50μm, line count 600LPI, coating pressure 0.5MPa, substrate speed 30m / min; LED excimer wave 308nm, irradiance 200mW / cm². 2 The curing distance is 30mm; the EB accelerating voltage is 200kV, the curing dose is 10kGy, the curing distance is 150mm, and the oxygen content is controlled to be ≤10ppm.

[0124] S2. Adjust the viscosity of the coating slurry to 150 mPa·s, and perform vacuum degassing after solid content calibration; the PET substrate is treated with a plasma cleaning machine to increase the surface tension to over 40 mN / m to obtain the slurry;

[0125] The slurry consists of: 40 parts SD6361, 1 part Tego4053, 4 parts E-1011, 6 parts Al2O3 / TM, 16 parts HDDA, 0.2 parts R972, 0.3 parts Tego 410, 0.5 parts Tego 2700, 0.2 parts Tego 920, 0.1 parts TPO, 5 parts MBF, 10 parts SD1363, 10 parts SD7832, 10 parts HDDA, and 17 parts TMCHA.

[0126] The pressure during vacuum degassing is -0.098 MPa;

[0127] S3. Feed the slurry into the micro-groove coating unit and coat it according to the set parameters to form a 10μm wet film. The coating gap is calibrated to 12μm using a feeler gauge.

[0128] S4. After wet film coating, the substrate enters the LED excimer curing unit through a 300mm transfer interval for low-temperature pre-curing, with the substrate surface temperature controlled at 25℃.

[0129] S5. The pre-cured substrate enters the EB accelerated curing unit through a 2m transfer interval and completes deep curing under nitrogen protection.

[0130] S6. The online film thickness gauge monitors the coating thickness as (5) μm, and the surface hardness is (2) H when sampled. There is no yellowing or pinhole defects. After passing the test, the coating is rolled up.

[0131] The optical film coating prepared in this embodiment has excellent uniformity, light transmittance ≥95%, and after 1000h of weather resistance testing (xenon arc aging test according to GB / T16422.2-2022), the color difference ΔE ≤2.0, indicating stable performance.

[0132] Comparative Example 1

[0133] In Comparative Example 1, the difference from Example 1 is that step S4 is removed.

[0134] The online film thickness gauge monitored the coating thickness as 5μm, and the surface hardness was 1H, yellowing, and pinhole defects were detected by sampling.

[0135] The optical film coating prepared in this embodiment has poor uniformity, light transmittance ≥80%, and after 1000h of weather resistance testing (xenon arc aging test according to GB / T16422.2-2022), the color difference ΔE ≥3.5, indicating unstable performance.

[0136] Comparative Example 2

[0137] In Comparative Example 2, the difference from Example 1 is that step S5 is removed.

[0138] The online film thickness gauge monitored the coating thickness as 5μm, and the surface hardness of the sampled surface was 1H, with yellowing and pinhole defects.

[0139] The optical film coating prepared in this embodiment has poor uniformity, light transmittance ≥85%, and after 1000h of weather resistance testing (xenon arc aging test according to GB / T16422.2-2022), the color difference ΔE ≥4.5, indicating unstable performance.

[0140] Comparative Example 3

[0141] In Comparative Example 3, the difference from Example 1 is that the micro-recessed coating in step S3 is a normal coating.

[0142] The online film thickness gauge monitored the coating thickness as 5μm, and the surface hardness of the sampled surface was 1H, with yellowing and pinhole defects.

[0143] The optical film coating prepared in this embodiment has poor uniformity, light transmittance ≥85%, and after 1000h of weather resistance testing (xenon arc aging test according to GB / T16422.2-2022), the color difference ΔE ≥4.0, indicating unstable performance.

[0144] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0145] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0146] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples. Additionally, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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; and these 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. A method for preparing a micro-recessed coating-LED pre-curing-EB curing coating, characterized in that, The process includes the following: The coating slurry and flexible substrate are pretreated to obtain the slurry and substrate; The slurry is micro-concave coated onto the surface of the substrate to form a uniform wet film, thereby obtaining a substrate coated with a wet film; The substrate with the coated wet film is subjected to low-temperature surface pre-curing of LED excimer lasers to obtain a pre-cured substrate; The pre-cured substrate is subjected to EB accelerated curing under an inert atmosphere, and then wound up to obtain the target micro-recessed LED pre-cured EB cured coating.

2. The method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to claim 1, characterized in that, The coating slurry comprises the following components in parts by weight: SD6361 30-50 parts, Tego 4053 0.5-1.2 parts, E-1011 4-6 parts, Al2O3 / TM 5-10 parts, HDDA 15-20 parts, R972 0.1-0.5 parts, Tego 410 0.1-0.5 parts, Tego2700 0.1-0.5 parts, Tego 920 0.1-0.5 parts, TPO 0.05-0.2 parts, MBF 3-6 parts, SD1363 8-12 parts, SD7832 8-12 parts, HDDA 8-12 parts, TMCHA 15-20 parts; The substrate includes PET film or polypropylene nonwoven fabric; In the step of pretreating the coating slurry and the flexible substrate, the coating slurry is subjected to viscosity testing, solid content calibration and vacuum degassing treatment.

3. The method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to claim 1, characterized in that, In the step of forming a uniform wet film by micro-grooving the slurry onto the surface of the substrate, the micro-grooving roller has a cell depth of 5μm~50μm, a line count of 100LPI~600LPI, a coating pressure of 0.1MPa~0.5MPa, a substrate speed of 5m / min~30m / min, a coating gap of 5μm~20μm, and a coating gap deviation of ≤±2μm.

4. The method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to claim 1, characterized in that, In the step of performing low-temperature surface pre-curing of the substrate with the coated wet film for LED excimer lasers, the wavelength is 222nm~308nm, the irradiation intensity is 50mW / cm²~200mW / cm², the curing distance is 10mm~30mm, and the surface temperature of the substrate with the coated wet film is ≤40℃.

5. The method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to claim 1, characterized in that, In the step of accelerating the curing of the pre-cured substrate under an inert atmosphere using EB, the accelerating voltage is 80kV~200kV, the curing dose is 3kGy~10kGy, the curing distance is 50mm~150mm, and the oxygen content is ≤50ppm.

6. The method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to claim 1, characterized in that, Inert atmospheres include nitrogen atmospheres.

7. The method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to claim 1, characterized in that, Micrografting is performed within a micrografting unit; and / or, LED excimer curing is performed in an LED excimer curing unit; and / or EB accelerated curing is carried out in the EB accelerated curing unit.

8. The method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to claim 7, characterized in that, The micro-grooving coating unit, the LED excimer curing unit, and the EB accelerated curing unit operate synchronously through a linkage conveying unit, with a linear speed deviation of ≤±1% and a correction accuracy of ±0.1mm for the linkage conveying unit. The transmission interval between the micro-grooving coating unit and the LE excimer curing unit is ≤500mm; the transmission interval between the LED excimer curing unit and the EB accelerated curing unit is 1m~3m.

9. A method for preparing a micro-recessed coating-LED pre-curing-EB-curing coating according to any one of claims 1 to 8, characterized in that, The coating thickness of the micro-recessed coating-LED pre-cured-EB cured coating is 1μm~50μm, the coating thickness uniformity is ≤±3%, the coating surface hardness is ≥1H, and the adhesion is ≥4B.

10. The application of the coating prepared by the preparation method according to any one of claims 1 to 9 in the preparation of optical films or new energy separators.

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