A UV-LED curing coating for new energy vehicle coating and its preparation method and application

Abstract

The present invention belongs to the field of coating technology, and specifically relates to a UV-LED curing coating for new energy vehicle coating, its preparation method, and application. The coating comprises the following components by mass: 30-50 parts of modified epoxy acrylate resin, 10-20 parts of polyurethane acrylate resin, 10-20 parts of modified polydimethylsiloxane, 5-10 parts of mixed photoinitiator, 1-3 parts of photosensitizer, 1-3 parts of leveling agent, 1-3 parts of antioxidant, 1-3 parts of defoaming agent, and 10-40 parts of water. The coating combines the advantages of UV-LED light sources and adopts a specially designed resin system and photoinitiator formula. It not only improves the adhesion and mechanical properties of the coating and improves the curing efficiency of the coating, but also has good electrical insulation properties, significantly improving the quality and efficiency of automobile coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and specifically relates to a UV-LED curing coating for new energy vehicle coating, and a preparation method and application thereof. Background Art

[0002] In recent years, ultraviolet (UV) curing technology has been widely adopted in various fields due to its advantages such as high efficiency, rapid speed, energy saving, and low pollution. It has particularly shown great potential in the automotive coating industry. UV-curable coatings cure quickly through ultraviolet radiation of a specific wavelength, significantly shortening production cycles, reducing energy consumption, and producing virtually no VOCs, making them an ideal environmentally friendly coating.

[0003] However, traditional UV-curable coatings have limitations, such as insufficient substrate adhesion and poor weather resistance, which restrict their application in high-end automotive coatings. Furthermore, due to the limitations of UV light sources, traditional UV-curable coatings may not fully cure in shadowed areas during the curing process, affecting coating quality.

[0004] With the development of LED technology, UV-LEDs, as a new light source, offer higher energy efficiency, longer lifespan, and better spectral controllability than traditional mercury lamps, effectively overcoming these issues. UV-LED-cured coatings not only achieve a more uniform and thorough cure, but also further reduce energy consumption and carbon footprint, aligning with future automotive manufacturing trends.

[0005] However, existing UV-LED-cured coatings still have some defects when used for new energy vehicle coatings, which limit their widespread adoption in high-end applications. New energy vehicles use a variety of materials, such as metals, plastics, and composites. Existing UV-LED-cured coatings have poor adhesion to certain substrates, especially on workpieces with complex shapes. Electrical components such as batteries and motors in new energy vehicles have high requirements for the electrical insulation properties of the coating, and existing UV-LED-cured coatings cannot fully meet these requirements. In addition, some UV-LED-cured coatings may become brittle and hard after curing, lacking sufficient flexibility and easily cracking when impacted or bent.

[0006] Therefore, there is an urgent need for a UV-LED curing coating suitable for new energy vehicle coating to solve the above problems. Summary of the Invention

[0007] The present invention aims to provide a UV-LED-curable coating suitable for new energy vehicle coatings, as well as its preparation method and application. This coating combines the advantages of UV-LED light sources with a specially designed resin system and photoinitiator formulation. This coating not only improves the coating's adhesion and mechanical properties, but also enhances its curing efficiency. It also exhibits excellent electrical insulation properties, significantly enhancing the quality and efficiency of automotive coatings.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A UV-LED curing coating suitable for coating new energy vehicles comprises the following components, measured by mass: 30-50 parts of modified epoxy acrylate resin, 10-20 parts of polyurethane acrylate resin, 10-20 parts of modified polydimethylsiloxane, 5-10 parts of mixed photoinitiator, 1-3 parts of photosensitizer, 1-3 parts of leveling agent, 1-3 parts of antioxidant, 1-3 parts of defoaming agent, and 10-40 parts of water.

[0010] Furthermore, the preparation method of the modified epoxy acrylate resin comprises the following steps:

[0011] (i) mixing methyl acrylate (MMA), butyl acrylate (BA) and hydroxyethyl acrylate (HEA), adding benzoyl peroxide (BPO) while stirring, heating to 60-80° C., and continuing stirring for 2-4 hours to obtain an acrylate polymer;

[0012] (ii) mixing epoxy resin E51 with the acrylate polymer obtained in step (i), stirring, adding dibutyltin dilaurate (DBTDL), heating to 70-90° C., and stirring for 1-2 hours to obtain the modified epoxy acrylate resin.

[0013] Furthermore, in step (i), the mass ratio of methyl acrylate (MMA), butyl acrylate (BA) and hydroxyethyl acrylate (HEA) is 5:(2-4):(1-3), and the mass of benzoyl peroxide (BPO) is 1-1.5% of the total mass of methyl acrylate (MMA), butyl acrylate (BA) and hydroxyethyl acrylate (HEA).

[0014] Furthermore, in step (ii), the mass ratio of epoxy resin E51 to acrylate polymer is 1:(0.8-1.2), and the mass of dibutyltin dilaurate (DBTDL) is 0.2-0.6% of the epoxy resin E51.

[0015] Because epoxy acrylate resin has excellent adhesion, can be firmly attached to a variety of substrates, and it can be quickly cured under UV-LED light source, improve production efficiency, therefore, the present invention attempts to use epoxy acrylate resin as the matrix resin of curing coating, but the inventor finds that unmodified epoxy acrylate resin is relatively brittle, and flexibility is insufficient, and after curing, coating is easily cracked when impacted or bent, therefore, the inventor has modified epoxy acrylate resin. Methyl acrylate, butyl acrylate and hydroxyethyl acrylate undergo free radical polymerization under the action of free radical initiator (BPO) to form acrylate polymer, epoxy group is ring-opened under the action of catalyst (DBTDL) to form active intermediate, these active intermediates can react with the hydroxyl group in acrylate polymer to form covalent bond, further forming a cross-linked network. This modification measure further improves the adhesion and mechanical strength of resin, and the introduction of butyl acrylate increases the flexible segment of resin, making resin difficult to crack or peel off when impacted or bent.

[0016] Furthermore, the preparation method of the modified polydimethylsiloxane comprises the following steps:

[0017] (a) γ-glycidyloxypropyltrimethoxysilane (KH560) and γ-aminopropyltrimethoxysilane (KH792) were added to polydimethylsiloxane in sequence, stirred for 10-15 minutes, dibutyltin dilaurate (DBTDL) was added, stirring was continued for 10-15 minutes, methyltrimethoxysilane (MTMS) was added, and stirring was continued for 10-15 minutes;

[0018] (b) heating the mixture obtained in step (a) to 70-90° C. and stirring the mixture for 2-5 hours to obtain the modified polydimethylsiloxane.

[0019] Furthermore, the mass ratio of the polydimethylsiloxane, γ-glycidyloxypropyltrimethoxysilane (KH560), γ-aminopropyltrimethoxysilane (KH792), and methyltrimethoxysilane (MTMS) is 10: (0.5-1.5): (0.5-1.5): (0.5-1.5), and the mass of the dibutyltin dilaurate (DBTDL) is 0.3-1% of the mass of the polydimethylsiloxane.

[0020] Adding polydimethylsiloxane to the formula of the present invention can improve the electrical insulation of the coating, but the addition of unmodified polydimethylsiloxane will affect the overall adhesion of the coating, which can easily cause the coating to fall off or peel off. The inventors found that after modifying polydimethylsiloxane using the method of the present invention, the adhesion can be significantly improved while maintaining excellent electrical insulation. The amino group in KH792 can react with the epoxy group in KH560 to form a cross-linked structure, and the amino group further reacts with the silanol group in polydimethylsiloxane to form a covalent bond, thereby enhancing the adhesion and mechanical properties of the resin. The trimethoxysilane group in MTMS undergoes a hydrolysis reaction to generate a silanol group, which undergoes a condensation reaction with the silanol group in polydimethylsiloxane, further strengthening the cross-linked network, so that the modified polydimethylsiloxane has excellent adhesion and mechanical properties.

[0021] Furthermore, the mixed photoinitiator is a mixture of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), 1-hydroxycyclohexyl phenyl ketone (184), and 2-isopropylthioxanthone (ITX), and the mass ratio of the three is (3-5): (1-2): (1-2).

[0022] The present invention uses three photoinitiators in a specific ratio, which can increase the spectral response range, increase the curing depth and speed, and improve the coating performance. 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO) mainly absorbs long-wave ultraviolet light, 1-hydroxycyclohexyl phenyl ketone (184) mainly absorbs medium-wave ultraviolet light, and 2-isopropylthioxanthone (ITX) mainly absorbs short-wave ultraviolet light. By compounding and using, it can be ensured that there is an efficient photoinitiation effect in different wavelength ranges, thereby improving the overall curing efficiency. The compounded photoinitiators can work synergistically to ensure that the polymerization reaction can be effectively initiated from the surface layer to the deep layer, thereby achieving uniform curing. In addition, the compounded photoinitiator can accelerate the generation and transfer of free radicals, increase the curing speed, and shorten the production cycle. The compounded photoinitiator can reduce the occurrence of side reactions and improve the comprehensive performance of the coating. Among them, the synergistic effect of TPO and 184 can reduce yellowing, and the addition of ITX can improve the weather resistance and chemical resistance of the coating. In addition, the compound photoinitiator can optimize the cross-linking density of the coating and improve the hardness, wear resistance and adhesion of the coating.

[0023] Furthermore, the photosensitizer is 2-hydroxy-2-methyl-1-phenylpropanone or 2,2-dimethoxy-2-phenylacetophenone.

[0024] Furthermore, the leveling agent is an acrylate leveling agent.

[0025] Furthermore, the antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(nonylphenyl)phosphite, and 2,2,6,6-tetramethylpiperidinol.

[0026] Furthermore, the defoaming agent is fatty acid ester or polyacrylate.

[0027] The present invention also provides a method for preparing the above-mentioned UV-LED curing coating, comprising the following steps:

[0028] (1) mixing modified epoxy acrylate resin, polyurethane acrylate resin and modified polydimethylsiloxane and stirring for 10-20 minutes;

[0029] (2) Add the mixed photoinitiator and photosensitizer and continue stirring for 10-20 minutes to evenly disperse;

[0030] (3) Add leveling agent, antioxidant and defoamer, continue stirring for 10-20 minutes and evenly disperse;

[0031] (4) Add water, adjust the viscosity, and stir for 10-20 minutes to obtain the UV-LED curing coating.

[0032] The present invention also provides the application of the above-mentioned UV-LED curing coating in the painting of new energy vehicles.

[0033] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0034] The UV-LED curing coating provided by the present invention significantly improves the adhesion and mechanical properties of the coating by using modified epoxy acrylate resin as the base resin, reducing the risk of the coating falling off or peeling off; the addition of modified polydimethylsiloxane significantly improves the electrical insulation of the coating, so that it exhibits good insulation effect under high voltage and high frequency environments; the compound photoinitiator improves the photoinitiation effect and improves the curing efficiency, allowing the use of lower power light sources, further saving energy and costs, thereby significantly improving the quality and efficiency of new energy vehicle coating. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Unless otherwise specified, the raw materials in the examples are all common commercially available products. The following is an exemplary description:

[0037] Epoxy resin E51 was purchased from Nan Ya Plastics Industrial Co., Ltd.;

[0038] Polydimethylsiloxane was purchased from Dow Corning (China) Co., Ltd., DC200;

[0039] Polyurethane acrylate resin was purchased from Covestro (Shanghai) Co., Ltd., Bayhydro l UH 2245;

[0040] Epoxy acrylate resin was purchased from Eastman Chemical, EBECRYL 8200;

[0041] 2,4,6-Trimethylbenzoyldiphenylphosphine oxide (TPO) was purchased from BASF (China) Co., Ltd.;

[0042] 1-Hydroxycyclohexylphenyl ketone (184) was purchased from Eastman Chemical (China) Co., Ltd.;

[0043] 2-Isopropylthioxanthone (I TX) was purchased from LANXESS Chemical (China) Co., Ltd.;

[0044] 2-Hydroxy-2-methyl-1-phenylpropanone was purchased from Clariant (China) Co., Ltd.;

[0045] Polyacrylate copolymer was purchased from BYK Chemical (China) Co., Ltd., BYK-354;

[0046] Butyl stearate was purchased from Nanjing Chemical Reagent Co., Ltd.

[0047] Polytetrafluoroethylene emulsion was purchased from Shanghai Sanaifu New Materials Co., Ltd., F-101.

[0048] Example 1

[0049] This embodiment provides a method for preparing a modified epoxy acrylate resin, comprising the following steps:

[0050] (i) Methyl acrylate (MMA), butyl acrylate (BA), and hydroxyethyl acrylate (HEA) are mixed in a clean reaction flask. The reaction flask is placed on a magnetic stirrer and stirred at 600 rpm. Benzoyl peroxide (BPO) is slowly added while stirring. Stirring is continued for 5 minutes. The reaction flask is transferred to a thermostatic water bath set at 70° C. and heated with continuous stirring for 3 hours to complete a free radical polymerization reaction. After the reaction is completed, the reaction flask is removed from the water bath and naturally cooled to room temperature to obtain an acrylate polymer.

[0051] The mass ratio of methyl acrylate (MMA), butyl acrylate (BA) and hydroxyethyl acrylate (HEA) is 5:3:2, and the amount of benzoyl peroxide (BPO) added is 1% of the total mass of the monomers (the total mass of MMA, BA and HEA);

[0052] (ii) Epoxy resin E51 was weighed and placed in a clean reaction flask. The reaction flask was placed on a magnetic stirrer, and the stirrer was started and stirred at 600 rpm. The acrylate polymer obtained in step (i) was added with stirring, and stirring was continued for 10 minutes. Dibutyltin dilaurate (DBTDL) was added and stirring was continued for 10 minutes. The reaction flask was moved to a thermostatic water bath set at 80° C. and heated with continuous stirring for 1.5 hours to complete the reaction between the epoxy groups and the hydroxyl groups. After the reaction was completed, the reaction flask was removed from the water bath and naturally cooled to room temperature to obtain a modified epoxy acrylate resin;

[0053] The mass ratio of epoxy resin E51 to acrylate polymer is 1:1, and the added mass of dibutyltin dilaurate (DBTDL) is 0.5% of the epoxy resin E51.

[0054] Example 2

[0055] This embodiment provides a method for preparing modified polydimethylsiloxane, comprising the following steps:

[0056] (1) Add polydimethylsiloxane to a clean reaction bottle, place the reaction bottle on a magnetic stirrer, start the stirrer, stir at 600 rpm, add KH560 and KH792, continue stirring for 10 minutes, add dibutyltin dilaurate (DBTDL), continue stirring for 10 minutes, add MTMS, and continue stirring for 10 minutes;

[0057] The mass ratio of polydimethylsiloxane, KH560, KH792, and MTMS is 10:1:1:1, and the mass of dibutyltin dilaurate (DBTDL) is 0.5% of the mass of polydimethylsiloxane;

[0058] (2) The reaction flask was moved to a constant temperature water bath, the temperature was set at 80°C, and the mixture was heated and stirred continuously for 3 hours. After the reaction was completed, the reaction flask was removed from the water bath and naturally cooled to room temperature to obtain modified polydimethylsiloxane.

[0059] Example 3

[0060] This embodiment provides a UV-LED curing coating suitable for new energy vehicle coating, which includes the following components, by mass: 40 parts of modified epoxy acrylate resin, 12 parts of polyurethane acrylate resin, 15 parts of modified polydimethylsiloxane, 8 parts of mixed photoinitiator, 2 parts of photosensitizer (2-hydroxy-2-methyl-1-phenylpropanone), 2 parts of leveling agent (polyacrylate copolymer), 1 part of antioxidant (2,6-di-tert-butyl-p-cresol), 1 part of defoaming agent (butyl stearate), and 20 parts of water.

[0061] The modified epoxy acrylate resin was prepared according to the method of Example 1.

[0062] The modified polydimethylsiloxane was prepared according to the method of Example 2.

[0063] The mixed photoinitiator is a mixture of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), 1-hydroxycyclohexyl phenyl ketone (184), and 2-isopropylthioxanthone (ITX), with a mass ratio of the three being 4:1:1.5.

[0064] The preparation method of the above-mentioned UV-LED curing coating comprises the following steps:

[0065] (1) mixing modified epoxy acrylate resin, polyurethane acrylate resin and modified polydimethylsiloxane and stirring for 15 minutes;

[0066] (2) Add the mixed photoinitiator and photosensitizer and continue stirring for 15 minutes to ensure uniform dispersion;

[0067] (3) Add leveling agent, antioxidant and defoamer and continue stirring for 15 minutes to ensure uniform dispersion;

[0068] (4) Add water to adjust the viscosity of the coating, and stir for 15 minutes to obtain the UV-LED curing coating.

[0069] Example 4

[0070] This embodiment provides a UV-LED curing coating suitable for new energy vehicle coating, which includes the following components in parts by mass: 35 parts of modified epoxy acrylate resin, 20 parts of polyurethane acrylate resin, 12 parts of modified polydimethylsiloxane, 6 parts of mixed photoinitiator, 2 parts of photosensitizer (2-hydroxy-2-methyl-1-phenylpropanone), 2 parts of leveling agent (polyacrylate copolymer), 1 part of antioxidant (2,6-di-tert-butyl-p-cresol), 1 part of defoaming agent (butyl stearate), and 20 parts of water; the rest is the same as Example 3.

[0071] Comparative Example 1

[0072] This comparative example provides a UV-LED curing coating suitable for coating new energy vehicles, which differs from Example 3 in that the modified epoxy acrylate resin is replaced by an unmodified epoxy acrylate resin.

[0073] Comparative Example 2

[0074] This comparative example provides a UV-LED curing coating suitable for coating new energy vehicles. The difference from Example 3 is that butyl acrylate is not added during the preparation of the modified epoxy acrylate resin.

[0075] Comparative Example 3

[0076] This comparative example provides a UV-LED curing coating suitable for coating new energy vehicles, which differs from Example 3 in that the modified polydimethylsiloxane is replaced by unmodified polydimethylsiloxane.

[0077] Comparative Example 4

[0078] This comparative example provides a UV-LED curing coating suitable for coating new energy vehicles. The difference from Example 3 is that KH792 is not added during the preparation of the modified polydimethylsiloxane.

[0079] Comparative Example 5

[0080] This comparative example provides a UV-LED curing coating suitable for new energy vehicle coating, which differs from Example 3 in that the mixed photoinitiator is 2,4,6-trimethylbenzoyldiphenylphosphine oxide and methyl benzoylformate, with a mass ratio of 2:1.

[0081] Comparative Example 6

[0082] This comparative example provides a UV-LED curing coating suitable for new energy vehicle coating. The difference from Example 3 is that the mass ratio of TPO, 184, and I TX in the mixed photoinitiator is 1:1:1.

[0083] Comparative Example 7

[0084] This comparative example provides a UV-LED curing coating suitable for coating new energy vehicles. The difference from Example 3 is that the modified polydimethylsiloxane is replaced by polytetrafluoroethylene emulsion.

[0085] Comparative Example 8

[0086] This comparative example provides a UV-LED curing coating suitable for new energy vehicle coating, which differs from Example 3 in that it includes the following components, in parts by mass: 55 parts of modified epoxy acrylate resin, 5 parts of polyurethane acrylate resin, 7 parts of modified polydimethylsiloxane, 8 parts of mixed photoinitiator, 2 parts of photosensitizer (2-hydroxy-2-methyl-1-phenylpropanone), 2 parts of leveling agent (polyacrylate copolymer), 1 part of antioxidant (2,6-di-tert-butyl-p-cresol), 1 part of defoaming agent (butyl stearate), and 20 parts of water.

[0087] Performance Testing

[0088] The cured coatings prepared in Example 3 and Comparative Examples 1-8 were coated on a substrate, cured using a UV-LED light source, and then the performance was tested.

[0089] Hardness was tested according to GB / T 6739-2006 "Determination of coating film hardness by pencil method"; adhesion was tested according to GB / T 9286-1998 "Paints and varnishes - Cross-cut test for paint films"; flexibility was tested according to GB / T 1731-1993 "Determination of flexibility of paint films"; impact strength was tested according to GB / T 1732-1993 "Test method for impact resistance of paint films"; abrasion resistance was tested according to GB / T 1768-2006 "Paints and varnishes - Determination of abrasion resistance (rotating rubber wheel)"; the complete drying time of the coating was tested according to GB T37362.1-2019 "Paints and varnishes - Drying tests - Part 1: Determination of the completely dried state and complete drying time"; and electrical insulation was tested according to GB / T 1410-2006 "Determination of volume resistivity and surface resistivity of solid insulating materials".

[0090] The test results are shown in Table 1.

[0091] Table 1 Performance test results

[0092]

[0093]

[0094] According to the above results, it can be seen that the UV-LED curing coating prepared by the present invention has excellent adhesion, mechanical strength, curing performance and electrical insulation performance. In Comparative Example 1, the modified epoxy acrylate resin is replaced by the unmodified epoxy acrylate resin. The unmodified epoxy acrylate resin lacks flexible segments and has strong intermolecular forces, which leads to increased brittleness of the coating and decreased hardness. The unmodified epoxy acrylate resin has fewer functional groups and weak chemical bonding with the substrate, so the adhesion is reduced. In Comparative Example 2, butyl acrylate is not added during the preparation of the modified epoxy acrylate resin. Similarly, due to the lack of flexible segments, the intermolecular forces are strong, resulting in increased brittleness of the coating and decreased hardness. In Comparative Example 3, the modified polydimethylsiloxane is replaced by the unmodified polydimethylsiloxane. The unmodified polydimethylsiloxane is mainly physically mixed in the resin system and lacks effective chemical bonding, resulting in decreased adhesion and other properties. In Comparative Example 4, the modified polydimethylsiloxane was prepared without the addition of KH792, and the cross-linked structure formed by the prepared polydimethylsiloxane was weak, so the mechanical properties were reduced. In Comparative Examples 5 and 6, the types or ratios of the mixed photoinitiators were changed, and the complementary advantages of the various photoinitiators could not be brought into play, resulting in a decrease in curing efficiency and a decrease in mechanical properties. In Comparative Example 7, the modified polydimethylsiloxane was replaced with polytetrafluoroethylene emulsion. Although polytetrafluoroethylene emulsion has excellent electrical insulation properties, after being added to the coating system, it may affect the distribution and interaction of other components, resulting in a decrease in overall electrical insulation performance. In addition, the molecular chain of polytetrafluoroethylene emulsion is relatively rigid and lacks sufficient flexible segments, which causes the coating to crack easily when bent or impacted. In Comparative Example 8, the ratio of the components was changed, especially the proportion of modified epoxy acrylate resin was increased, while the proportions of polyurethane acrylate resin and modified polydimethylsiloxane were reduced, resulting in a decrease in the overall performance of the coating. Although the modified epoxy acrylate resin has good adhesion, excessive use will increase the brittleness of the coating and reduce its flexibility and adhesion.

[0095] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A UV-LED curing coating suitable for coating new energy vehicles, comprising the following components, by mass: 30-50 parts of modified epoxy acrylate resin, 10-20 parts of polyurethane acrylate resin, 10-20 parts of modified polydimethylsiloxane, 5-10 parts of mixed photoinitiator, 1-3 parts of photosensitizer, 1-3 parts of leveling agent, 1-3 parts of antioxidant, 1-3 parts of defoaming agent, and 10-40 parts of water; The mixed photoinitiator is a mixture of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, and 2-isopropylthioxanthone, with a mass ratio of the three being (3-5): (1-2): (1-2); The preparation method of the modified epoxy acrylate resin comprises the following steps: (i) mixing methyl acrylate, butyl acrylate, and hydroxyethyl acrylate, adding benzoyl peroxide while stirring, heating to 60-80° C., and continuing stirring for 2-4 hours to obtain an acrylate polymer; (ii) epoxy resin E51 and the acrylate polymer obtained in step (i) are mixed, stirred, dibutyltin dilaurate is added, heated to 70-90° C., and stirred for 1-2 hours to obtain the modified epoxy acrylate resin.

2. The UV-LED curing coating according to claim 1, characterized in that In step (i), the mass ratio of methyl acrylate, butyl acrylate and hydroxyethyl acrylate is 5:(2-4):(1-3), and the mass of benzoyl peroxide is 1-1.5% of the total mass of methyl acrylate, butyl acrylate and hydroxyethyl acrylate.

3. The UV-LED curing coating according to claim 1, characterized in that In step (ii), the mass ratio of epoxy resin E51 to acrylate polymer is 1:(0.8-1.2), and the mass of dibutyltin dilaurate is 0.2-0.6% of the epoxy resin E51.

4. The UV-LED curing coating according to claim 1, characterized in that The preparation method of the modified polydimethylsiloxane comprises the following steps: (a) adding γ-glycidyloxypropyltrimethoxysilane and γ-aminopropyltrimethoxysilane to polydimethylsiloxane in sequence, stirring for 10-15 minutes, adding dibutyltin dilaurate, continuing stirring for 10-15 minutes, adding methyltrimethoxysilane, and continuing stirring for 10-15 minutes; (b) heating the mixture obtained in step (a) to 70-90° C. and stirring the mixture for 2-5 hours to obtain the modified polydimethylsiloxane.

5. The UV-LED curing coating according to claim 4, characterized in that: The mass ratio of the polydimethylsiloxane, γ-glycidyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane and methyltrimethoxysilane is 10:(0.5-1.5):(0.5-1.5):(0.5-1.5), and the mass of the dibutyltin dilaurate is 0.3-1% of the mass of the polydimethylsiloxane.

6. The UV-LED curing coating according to claim 1, characterized in that The photosensitizer is 2-hydroxy-2-methyl-1-phenylpropanone or 2,2-dimethoxy-2-phenylacetophenone, the leveling agent is an acrylate leveling agent, the antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(nonylphenyl)phosphite, and 2,2,6,6-tetramethylpiperidinol, and the defoaming agent is a fatty acid ester or a polyacrylate.

7. A method for preparing the UV-LED curing coating according to any one of claims 1 to 6, comprising the following steps: (1) mixing modified epoxy acrylate resin, polyurethane acrylate resin and modified polydimethylsiloxane and stirring for 10-20 minutes; (2) Add the mixed photoinitiator and photosensitizer and continue stirring for 10-20 minutes to evenly disperse; (3) Add leveling agent, antioxidant and defoamer, continue stirring for 10-20 minutes and evenly disperse; (4) Add water, adjust the viscosity, and stir for 10-20 minutes to obtain the UV-LED curing coating.

8. Use of the UV-LED curing coating according to any one of claims 1 to 6 in the coating of new energy vehicles.

9. Application of the UV-LED curing coating prepared by the preparation method according to claim 7 in the coating of new energy vehicles.

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