An environmentally-friendly solvent-free UV battery box coating formula, preparation method and application method for replacing blue film

Abstract

This invention discloses a formulation, preparation method, and application method of an environmentally friendly solvent-free UV battery box coating that can replace blue film, belonging to the field of UV curable coatings and new energy battery protection technology. The coating is a 100% solids-containing solvent-free system, and its formulation includes: polyurethane acrylate, silicone-modified acrylate; TMPTA, IBOA, DMAA; TPO / L-TPO type acylphosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, methyl benzoylformate; titanium dioxide, phthalocyanine blue, fumed silica; adhesion promoter, leveling agent, and silane coupling agent. This coating has zero VOC, insulation withstand voltage ≥DC6000V / 60s, adhesion grade 0, no abnormalities after 72h electrolyte resistance, and UL94V0 flame retardancy. It can be applied in various ways, replacing PET blue film and pressure-sensitive adhesive processes, meeting the insulation protection and green manufacturing requirements of high-voltage platform power batteries.

Description

Technical Field

[0001] This invention belongs to the field of new energy battery protective curing coating technology, specifically relating to the formulation, preparation method and application method of an environmentally friendly solvent-free UV battery box coating that can replace blue film. Background Technology

[0002] Currently, the mainstream insulation and protection solution for power battery boxes and battery pack shells is a composite coating process using PET blue film and pressure-sensitive adhesive. This process achieves insulation, pressure resistance, scratch resistance, and marking functions on the shell surface through film application and has been widely used in the new energy vehicle industry. However, with the popularization of high-voltage fast charging technology and the in-depth advancement of integrated design concepts such as CTP (module-less) and CTC (cell-to-chassis), the limitations of the existing blue film system are becoming increasingly prominent, making it difficult to meet the comprehensive requirements of next-generation power batteries for safety, reliability, process efficiency, and environmental protection.

[0003] Specifically, the existing technology has the following main problems: First, the insulation withstand voltage capability is insufficient. The withstand voltage level of the existing blue film system is usually only about 2500V / 60s, while the current high voltage platform has generally raised the requirements for the insulation performance of the battery box to DC5000V-6000V / 60s. The blue film is difficult to meet the safety redundancy requirements of higher voltage platforms and there is a risk of insulation breakdown.

[0004] Secondly, the structural reliability is poor. The blue membrane relies on pressure-sensitive adhesive to bond with the shell, which is prone to warping, wrinkling, and detachment during long-term use. Especially under conditions of thermal shock, vibration, and humid aging, the adhesive performance of the adhesive layer deteriorates significantly, leading to insulation failure. At the same time, it is difficult to achieve a completely seamless bond between the membrane and the shell, leaving air gaps that affect insulation reliability and reduce heat conduction efficiency, adversely impacting the heat dissipation of the battery system.

[0005] Third, it has insufficient chemical resistance and weather resistance. The pressure-sensitive adhesive layer has limited resistance to electrolytes and high temperature and humidity environments. Long-term use can easily lead to swelling, softening or adhesion decay, which in turn accelerates the deterioration of protective performance.

[0006] Fourth, environmental protection and recycling pressures are prominent. Both blue film and pressure-sensitive adhesive are multi-layered composite structures, making material separation and recycling difficult. Their use generates a large amount of mixed waste, which is inconsistent with the development direction of green manufacturing and a circular economy. Furthermore, some existing solvent-based coating processes still have VOC emission issues and face increasingly stringent environmental regulations.

[0007] Fifth, the process is inefficient and the overall cost is high. Blue film coating is mostly done manually or semi-automatically, which is complicated, requires high alignment accuracy, and has large fluctuations in yield. It is difficult to meet the cycle time requirements of high-speed automated production lines in the new energy industry, and the overall cost of materials and processes remains high.

[0008] In summary, there is an urgent need to develop a novel coating system that is solvent-free, VOC-free, can be cured efficiently, and possesses high insulation and voltage resistance, excellent adhesion, electrolyte resistance, flame retardancy, and weather resistance. This system would provide a one-stop replacement for PET blue film and pressure-sensitive adhesive processes, thereby meeting the dual requirements of high-voltage platform battery safety protection and green manufacturing. Summary of the Invention

[0009] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a formulation, preparation method, and application method for an environmentally friendly, solvent-free UV battery box coating that can replace blue film.

[0010] The present invention provides a formulation for an environmentally friendly solvent-free UV battery box coating that can replace blue film, comprising, by weight: 50-70 parts of oligomeric main resin, 20-30 parts of compound monomers, 4-8 parts of compound photoinitiator, 5-10 parts of compound pigments and fillers, and 2-5 parts of functional additives.

[0011] The oligomer base resin includes polyurethane acrylate and silicone-modified acrylate; through compounding, it provides high adhesion, high flexibility, high weather resistance, and pressure resistance.

[0012] The compound monomers are trimethylolpropane triacrylate (TMPTA), isobornyl acrylate (IBOA), and N,N-dimethylacrylamide (DMAA) to adjust viscosity, increase crosslinking density, and improve curing rate.

[0013] The composite photoinitiator includes acylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and methyl benzoylformate; it is compatible with UV-LEDs at 365 / 395nm, enabling simultaneous surface and bottom curing without yellowing. Methyl benzoylformate provides high reactivity and surface curing; phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is specifically designed for deep and thick films, offering resistance to yellowing and masking; acylphosphine oxide balances surface and deep curing, with low yellowing improving electrolyte resistance and thermal shock reliability.

[0014] The compound pigments and fillers include titanium dioxide, phthalocyanine blue, and fumed silica; they provide color, improve rheological properties, insulation strength, and flame retardancy.

[0015] Functional additives, matched with the formulated materials used, can improve adhesion, impact resistance, leveling, electrolyte resistance, and durability by adding functional additives. These include: silane coupling agents containing epoxy functional groups: their epoxy groups can form chemical bonds with the hydroxyl groups and metal oxides on the surface of the battery box substrate, and their siloxane groups can combine with the hydroxyl groups on the surface of the compound pigments and fillers (titanium dioxide, fumed silica), while simultaneously forming an interfacial bridge with the oligomeric main resin (polyurethane acrylate, silicone-modified acrylate), used to improve the adhesion between the coating and the substrate, pigments and fillers, reduce internal stress in the system, improve the dispersibility of pigments and fillers, and ensure the weather resistance and thermal shock resistance of the paint film; acrylate phosphate type adhesion promoters containing polymerization inhibitors: the phosphate groups can form a strong chelating effect with the substrate, and the acrylate double... The bonds can participate in the UV curing reaction and copolymerize with the oligomer main resin and compound monomers (TMPTA, IBOA, DMAA). The polymerization inhibitor can improve the storage stability and leveling properties of the coating, while enhancing the coating film's resistance to electrolyte erosion and strengthening the adhesion between the coating and the metal substrate. Polyester-modified polydimethylsiloxane or acrylated polysiloxane leveling agents containing polyacrylate functional groups: The polyacrylate functional groups can react with the entire UV curing system (oligomer main resin and compound monomers) and bind to the coating film. The polydimethylsiloxane structure can reduce the surface tension of the coating, improve the leveling properties of the solvent-free high-viscosity system, avoid defects such as pinholes and fisheyes in the coating film, improve the coating's wettability and edge coverage of the complex structure of the battery box, and do not affect the subsequent assembly performance of the coating film.

[0016] Preferably, in the oligomer-based resin, the weight ratio of polyurethane acrylate to silicone-modified acrylate is 45-55:8-12, and both polyurethane acrylate and silicone-modified acrylate are 100% solvent-free resins.

[0017] Preferably, in the compound monomers, the weight ratio of TMPTA:DMAA:IBOA is 10-18:5-7:3-8.

[0018] Preferably, in the composite photoinitiator, the weight ratio of acylphosphine oxide: methyl benzoylcarbamate: phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide is 3-4:0.8-1.2:1.3-1.6; and the acylphosphine oxide is TPO / L-TPO.

[0019] Preferably, in the compound pigment and filler, the weight ratio of titanium dioxide:phthalocyanine blue:fumed silica is 2.5-2.8:0.9-1.1:2.8-3.2.

[0020] Preferably, in acrylate phosphate type adhesion promoters containing polymerization inhibitors, the polymerization inhibitor is hydroquinone monomethyl ether (MEHQ); the silane coupling agent containing epoxy functional groups is specifically γ-glycidyl ether propyltrimethoxysilane coupling agent. Compared to other polymerization inhibitors, MEHQ can be photolyzed or actively diluted under UV light, and its inhibitory effect disappears reversibly, without hindering the UV curing process, ensuring that the coating quickly reaches simultaneous surface and basal drying. Ensuring the copolymerization effectiveness of the adhesion promoter: The molecular structure of the adhesion promoter contains key acrylate double bonds, which must fully participate in the crosslinking reaction under UV light to form a strong electrolyte-resistant curing network. Selection criteria: MEHQ has moderate polymerization inhibition efficiency and thermal stability, locking the activity of the double bonds while rapidly inactivating them upon UV irradiation, allowing the double bonds to immediately participate in copolymerization. Technical results: This ensures that the adhesion promoter does not leave residues or migrate, and can firmly bind into the paint film matrix, thereby guaranteeing durable adhesion and insulation reliability to the metal substrate. The best balance between overall performance and safety: Compatibility: MEHQ is compatible with the polyurethane acrylate, silicone-modified acrylate and compound monomer system in this invention, and will not cause pinholes, fish eyes or reduced transparency in the paint film due to precipitation or poor dispersion.

[0021] A method for preparing an environmentally friendly, solvent-free UV battery box coating that can replace blue film, using the above-mentioned coating formulation, specifically includes the following steps:

[0022] S1. Mix the oligomer main resin and monomer and stir until homogeneous;

[0023] S2. After adding functional additives, perform dispersion operations;

[0024] S3. After the dispersion process is completed, add the compound pigments and fillers, and then perform a sand milling operation.

[0025] S4. After the sand milling operation is completed, the compound photoinitiator is added after cooling and stirred to dissolve it.

[0026] S5. After the stirring and dissolving process is completed, the coating is filtered and degassed to obtain the target coating.

[0027] Preferably, in step S3, the grinding fineness is required to be ≤10μm.

[0028] An application method for an environmentally friendly, solvent-free UV battery box coating that can replace blue film, using the coating prepared above, specifically includes the following steps: Application: Apply the coating by spraying, rolling, or curtain coating, requiring a dry film thickness of 110-150μm; Curing: Use a 365nm / 395nm UV-LED curing light source, controlling the curing energy to 400-2000mJ / cm², to achieve surface drying and curing in seconds.

[0029] Compared with existing PET blue film and pressure-sensitive adhesive coating processes, the environmentally friendly solvent-free UV battery box coating provided by this invention, which replaces blue film, has the following beneficial effects:

[0030] (1) Significantly improved environmental performance. The coating of this invention is a 100% solids-containing solvent-free system with zero VOC emissions, eliminating the release of volatile organic compounds from the source. It fully complies with the increasingly stringent national and global standards for volatile organic compound emissions and green manufacturing requirements, while avoiding the environmental pain points of the blue film and pressure-sensitive adhesive composite structure being difficult to recycle and generating a large amount of mixed waste.

[0031] (2) The insulation withstand voltage performance is greatly improved. The insulation withstand voltage can reach DC6000V / 60s or more, which is much higher than the existing blue film system of 2500V / 60s. It can fully meet the requirements of high voltage platform (5000V-6000V) for insulation safety redundancy and effectively reduce the risk of high voltage breakdown.

[0032] (3) Excellent protective reliability. The coating forms a seamless, fully enclosed structure with the aluminum / steel shell, eliminating the unavoidable air gaps during the blue film bonding process, and significantly improving insulation reliability and heat conduction efficiency. Test results show that the coating adhesion reaches level 0, it has no abnormalities after immersion in electrolyte for 72 hours, no abnormalities after 1000 hours of humid heat aging at 85℃ / 85%RH, and its flame retardant performance reaches UL94V0 level. It also has good resistance to thermal shock and impact resistance, solving the problems of easy edge lifting, wrinkling, peeling, poor electrolyte resistance and temperature resistance of the blue film.

[0033] (4) High process efficiency and low overall cost. The coating of this invention can be applied by automated methods such as spraying and rolling, and can be cured in seconds with UV-LED (365 / 395nm). The curing energy consumption is low and the production line cycle is fast, which can greatly improve the production efficiency. The target dry film thickness can be achieved in one application, without the need for cumbersome processes such as film application and pressing, reducing labor and equipment investment, simplifying the process flow, and the overall manufacturing cost is significantly lower than that of blue film and pressure-sensitive adhesive systems.

[0034] (5) High adaptability, meeting the requirements of integrated design. The coating can be uniformly applied according to the shape of the shell, without being limited by complex structures. It is particularly suitable for the stringent requirements of shell insulation protection in highly integrated battery systems such as CTP and CTC, avoiding the process bottlenecks caused by issues such as size matching and bonding accuracy of the blue film.

[0035] In summary, this invention achieves a comprehensive replacement and improvement over the existing blue film system in terms of environmental performance, insulation withstand voltage, protection reliability, process efficiency, and overall cost, providing an efficient, green, and reliable solution for the insulation protection of power batteries and energy storage battery boxes for new energy vehicles. Detailed Implementation

[0036] The following are specific embodiments of the present invention, which further describe the technical solutions, but are not limited to these embodiments.

[0037] Example 1

[0038] A formulation for an environmentally friendly, solvent-free UV battery box coating that can replace blue film includes: 52 parts polyurethane acrylate, 8 parts silicone-modified acrylate, 16 parts trimethylolpropane triacrylate (TMPTA), 6 parts N,N-dimethylacrylamide (DMAA), 3 parts isobornyl acrylate (IBOA), 3 parts TPO, 1 part methyl benzoylformate (MBF), 1.5 parts phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819), 2.5 parts titanium dioxide, 1 part phthalocyanine blue, 3 parts fumed silica, 1 part adhesion promoter, 1.2 parts leveling agent, and 0.8 parts silane coupling agent; adhesion promoter: Mair Chemical HY-9500.

[0039] Leveling agent: TEGO Rad 2100; Silane coupling agent: Momentive A-187; Total: 100 parts.

[0040] The preparation method of the coating is as follows: S1. Mix the oligomer main resin and monomer and stir evenly; S2. Add functional additives and disperse; S3. After dispersion, add compound pigments and fillers and perform sand milling; S4. After sand milling, cool and add compound photoinitiator and stir to dissolve; S5. After stirring and dissolving, filter and degas to obtain the target coating.

[0041] Application methods are as follows: Application: Apply by spraying, rolling, or curtain coating, with a required dry film thickness of 110-150μm; Curing: Use a 365nm / 395nm UV-LED curing light source and control the curing energy to 400-2000mJ / cm² to achieve surface drying and curing in seconds.

[0042] Example 2

[0043] A formulation for an environmentally friendly, solvent-free UV battery box coating that can replace blue film includes: 52 parts polyurethane acrylate, 8 parts silicone-modified acrylate, 16 parts TMPTA, 4 parts DMAA, 5 parts IBOA, 3 parts TPO, 1 part MBF, 1.5 parts 819, 2.5 parts titanium dioxide, 1 part phthalocyanine blue, 3 parts fumed silica, 1 part adhesion promoter, 1.2 parts leveling agent, and 0.8 parts silane coupling agent; adhesion promoter: Mair Chemical HY-9500; leveling agent: TEGO Rad 2100; silane coupling agent: Momentive A-187; total: 100 parts.

[0044] The preparation method of the coating is as follows: S1. Mix the oligomer main resin and monomer and stir evenly;

[0045] S2. After adding functional additives, perform dispersion. S3. After dispersion, add compound pigments and fillers and perform sand milling. S4. After sand milling, cool down and add compound photoinitiator, and perform stirring and dissolving. S5. After stirring and dissolving, perform filtration and degassing to obtain the target coating.

[0046] Application methods are as follows: Application: Apply by spraying, rolling, or curtain coating, with a required dry film thickness of 110-150μm; Curing: Use a 365nm / 395nm UV-LED curing light source and control the curing energy to 400-2000mJ / cm² to achieve surface drying and curing in seconds.

[0047] Example 3

[0048] A formulation for an environmentally friendly, solvent-free UV battery box coating that can replace blue film includes: 47 parts polyurethane acrylate, 10 parts silicone-modified acrylate, 12 parts TMPTA, 6 parts DMAA, 7 parts IBOA, 3 parts TPO, 1 part MBF, 1.5 parts 819, 2.5 parts titanium dioxide, 1 part phthalocyanine blue, 3 parts fumed silica, 1 part adhesion promoter, 1.2 parts leveling agent, and 0.8 parts silane coupling agent. The adhesion promoter is Mair Chemical HY-9500; the leveling agent is TEGO Rad 2100; and the silane coupling agent is Momentive A-187. The total amount is 100 parts.

[0049] The preparation method of the coating is as follows: S1. Mix the oligomer main resin and monomer and stir evenly; S2. Add functional additives and disperse; S3. After dispersion, add compound pigments and fillers and perform sand milling; S4. After sand milling, cool and add compound photoinitiator and stir to dissolve; S5. After stirring and dissolving, filter and degas to obtain the target coating.

[0050] Application methods are as follows: Application: Apply by spraying, rolling, or curtain coating, with a required dry film thickness of 110-150μm; Curing: Use a 365nm / 395nm UV-LED curing light source and control the curing energy to 400-2000mJ / cm² to achieve surface drying and curing in seconds.

[0051] The coating of this invention was tested, and the test results of its key performance indicators are shown in Table 1:

[0052] Test Project Example 1 Example 2 Example 3 Solid content 100% 100% 100% VOC (g / L) 0 0 0 Fineness ≤10μm ≤10μm ≤10μm Gloss (60°) 93 95 96 Thickness (dry film) 122μm 127μm 132μm Adhesion (100-grid test) Level 0 Level 0 Level 0 hardness 2H 2H 2H Insulation withstand voltage ≥6000V ≥6000V ≥6000V Electrolyte resistance for 72 hours No abnormalities No abnormalities No abnormalities 85℃ / 85%RH 1000h No abnormalities No abnormalities No abnormalities Flame retardant UL94 V0 V0 V0

[0053] Table 1

[0054] Test Result Analysis: Insulation Withstand Voltage Performance: The insulation withstand voltage of the coating of this invention reaches over DC 6000V / 60s (dry film thickness 110-150μm), far exceeding the withstand voltage level of existing blue film systems. Traditional PET blue films only support a maximum breakdown voltage of 2500V, while 800V high-voltage platforms require insulation materials with a breakdown voltage of 3000-4000V. The coating of this invention can fully meet the insulation safety redundancy requirements of current and future higher voltage platforms, effectively reducing the risk of high-voltage breakdown.

[0055] 2. Adhesion and Bonding Strength: The coating of this invention achieves an adhesion rating of 0 (100-cross cross-cut adhesion test), indicating a tight bond between the coating and the aluminum / steel substrate. This achieves a high-strength bond between the coating and the metal substrate, meeting the stringent shear strength requirements of next-generation power batteries.

[0056] 3. Weather Resistance and Chemical Resistance: The coating of this invention showed no abnormalities after 1000 hours of humid heat aging at 85℃ / 85%RH, and showed no swelling or peeling after immersion in electrolyte for 72 hours. Blue films are prone to aging under the same humid heat conditions, leading to a decrease in insulation performance and insufficient resistance to electrolyte corrosion. This invention significantly improves the coating's resistance to humid heat aging and chemical corrosion, ensuring safe protection throughout the battery's entire lifespan.

[0057] 4. Flame Retardant Performance: The coating of this invention achieves a UL94V0 flame retardant rating, the highest level, and does not burn or spread when exposed to fire. This invention achieves excellent flame retardant properties through the compound design of pigments and fillers (such as fumed silica), which helps reduce the risk of battery thermal runaway and improves system safety.

[0058] 5. Environmental Characteristics: The coating of this invention is a 100% solids-free solvent-free system with zero VOC emissions, fully complying with green manufacturing requirements. The solvent-free formulation not only eliminates VOC emissions but also reduces material usage, significantly lowering the environmental burden. In contrast, blue film production uses volatile organic compounds, and its multi-layered composite structure is difficult to recycle.

[0059] In summary, the coating of this invention significantly outperforms existing blue film systems in terms of insulation withstand voltage, adhesion, weather resistance, chemical resistance, flame retardancy, and environmental friendliness, with key indicators reaching or exceeding industry-leading levels. In particular, its insulation withstand voltage exceeding DC6000V, UL94V0 flame retardancy rating, and 100% solvent-free and zero VOC characteristics enable it to fully meet the stringent insulation protection requirements of high-voltage power batteries, achieving a one-stop replacement for PET blue film and pressure-sensitive adhesive processes.

[0060] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or substitute them with similar methods, without departing from the spirit of the invention or exceeding its defined scope. Although the invention has been described in detail above, such descriptions are considered illustrative or exemplary rather than restrictive. It should be understood that changes and modifications can be made by those skilled in the art within the scope of the following claims.

Claims

1. A formulation for an environmentally friendly, solvent-free UV battery box coating that can replace blue film, characterized in that, By weight, it includes: 50-70 parts of oligomer main resin, 20-30 parts of compound monomers, 4-8 parts of compound photoinitiator, 5-10 parts of compound pigments and fillers, and 2-5 parts of functional additives. The oligomer main resins include polyurethane acrylates and silicone-modified acrylates; The compound monomers include TMPTA, IBOA, and DMAA; The composite photoinitiators include acylphosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, and methyl benzoylformate; The compound pigments and fillers include titanium dioxide, phthalocyanine blue, and fumed silica; Functional additives include: silane coupling agents containing epoxy functional groups, acrylate phosphate type adhesion promoters containing polymerization inhibitors, and polyester-modified polydimethylsiloxane or acrylated polysiloxane type leveling agents containing polyacrylate functional groups.

2. The formulation of the environmentally friendly solvent-free UV battery box coating as described in claim 1, characterized in that, In the oligomer-based resin, the weight ratio of polyurethane acrylate to silicone-modified acrylate is 45-55:8-12, and both polyurethane acrylate and silicone-modified acrylate are 100% solid content solvent-free resins.

3. The formulation of the environmentally friendly solvent-free UV battery box coating as described in claim 1, characterized in that, In the compound monomers, the weight ratio of TMPTA:DMAA:IBOA is 10-18:5-7:3-8.

4. The formulation of the environmentally friendly solvent-free UV battery box coating as described in claim 1, characterized in that, In the complex photoinitiator, the weight ratio of acylphosphine oxide: methyl benzoate: phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide is 3-4: 0.8-1.2:1.3-1.6, acylphosphine oxide is TPO / L-TPO.

5. The formulation of the environmentally friendly solvent-free UV battery box coating as described in claim 1, characterized in that, In the compound pigments and fillers, the weight ratio of titanium dioxide:phthalocyanine blue:fumed silica is 2.5-2.8:0.9-1.1:2.8-3.

2.

6. The formulation of the environmentally friendly solvent-free UV battery box coating as described in claim 1, characterized in that, In acrylate phosphate type adhesion promoters containing polymerization inhibitors, the polymerization inhibitor is hydroquinone monomethyl ether; the silane coupling agent containing epoxy functional groups is specifically γ-glycidyl ether propyltrimethoxysilane coupling agent.

7. A method for preparing an environmentally friendly solvent-free UV battery box coating that replaces the blue film, comprising using the formulation of any of the environmentally friendly solvent-free UV battery box coatings that replace the blue film as described in claims 1-6, characterized in that, Specifically, the following steps are included: S1. Mix the oligomer main resin and monomer and stir until homogeneous; S2. After adding functional additives, perform dispersion operations; S3. After the dispersion process is completed, add the compound pigments and fillers, and then perform a sand milling operation. S4. After the sand milling operation is completed, the compound photoinitiator is added after cooling and stirred to dissolve it. S5. After the stirring and dissolving process is completed, the coating is filtered and degassed to obtain the target coating.

8. The preparation method of an environmentally friendly solvent-free UV battery box coating as a substitute for blue film as described in claim 7, characterized in that, In step S3, the grinding fineness is required to be ≤10μm.

9. A method for applying an environmentally friendly, solvent-free UV battery box coating that replaces the blue film, comprising using the environmentally friendly, solvent-free UV battery box coating that replaces the blue film prepared by the method described in claim 7, characterized in that... Specifically, the following steps are included: Application: Apply by spraying, rolling, or curtain coating, with a required dry film thickness of 110-150μm; Curing: A 365nm / 395nm UV-LED curing light source is used, and the curing energy is controlled at 400-2000mJ / cm² to achieve surface drying and curing in seconds.