Mirror leveling UV (ultraviolet) coating as well as preparation method and application thereof

Abstract

The invention discloses a mirror surface leveling UV (ultraviolet) coating as well as a preparation method and application thereof, and the mirror surface leveling UV coating can be used in a preparation process of an electronic product shell. Comprising the following components in parts by weight: 30-45 parts of hydroxyl-containing aliphatic polyurethane acrylate, 8-15 parts of poly-carbon type polyurethane acrylate, 3-5 parts of high-functionality polyurethane acrylate, 3-5 parts of electrosilvering resin, 2-5 parts of a photoinitiator, 1-2 parts of a flatting agent and 35-45 parts of a diluent. The mirror surface leveling UV coating inhibits the generation of surface tension gradient of the edge and the middle part of a workpiece in the flash drying process of a paint film on one hand, effectively improves the edge accumulation phenomenon, obtains other characteristics such as good leveling property, humidity and heat resistance and toughness on the other hand, and is simple in preparation process, low in requirements on production equipment and suitable for large-scale industrial production; the perfect mirror surface edge-accumulation-free coating can be directly obtained on the surface of the electronic equipment shell, and compared with an existing process, the process complexity and the production cost are greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a mirror-leveling UV coating and a preparation method and application thereof. Background Art

[0002] In order to avoid paint accumulation on the edge coating of workpieces such as mobile phone middle frames and obtain mobile phone middle frame products with flawless coatings, our company proposed a new type of easily peelable coating and a process based on the coating, which first performs a vacuum coating process on the PC mobile phone middle frame material, and then performs edge CNC + touch-up and paint stripping. The coating and process have been successfully applied to a certain brand of mobile phone terminals. However, in the actual production process, the coating and process still have the following technical problems: the vacuum plating paint scratch defect rate is high after the workpiece is stripped, and the process cost is high, which is not conducive to product promotion.

[0003] Therefore, it is urgent to develop new products and methods to obtain coatings that meet performance requirements and reduce production costs and improve economic benefits. Summary of the invention

[0004] The present invention provides a mirror-leveling UV coating and a preparation method and application thereof, which are used to solve the technical problems mentioned in the background technology that the coating formed by the existing UV curing coating has a low yield, a complex use process and a high cost.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A mirror-leveling UV coating comprises the following components in parts by weight: 30~45 parts of hydroxyl-containing aliphatic polyurethane acrylate, 8~15 parts of polycarbonate polyurethane acrylate, 3~5 parts of high-functionality polyurethane acrylate, 3~5 parts of electroplating silver resin, 2~5 parts of photoinitiator, 1~2 parts of leveling agent and 35~45 parts of diluent.

[0006] The design idea of ​​the above technical solution is that the present invention studies the phenomenon that paint is easy to accumulate on the edge of the workpiece (such as the right-angle edge of the middle frame of a mobile phone). The phenomenon is caused by the surface tension gradient, and the vapor pressure of the solvent is related to the liquid surface state in which it is located. The vapor pressure of a convex surface is higher than that of a flat surface, and the smaller the radius of curvature of the convex surface, the greater the vapor pressure. At the edge of the right-angled middle frame, the coating film has a relatively large specific surface area and is in a convex surface state with a small radius of curvature. Therefore, the solvent there often evaporates faster. If the surface tension of the solvent is lower than the surface tension of the system resin and pigment, after the solvent in the paint film evaporates, the surface tension at the edge increases more than the inside, and there will be a gradient in which the surface tension gradually decreases from the edge to the inside. The low surface tension part in the middle flows to the high surface tension part at the edge, causing the edge thickening phenomenon. On the one hand, the present invention suppresses the generation of surface tension gradient between the edge and the middle of the workpiece during the flash drying process of the paint film by optimizing the combination of resin and auxiliary agent, and accelerates the flash drying of the solvent in the wet film state of the coating by adding a small amount of high molecular weight electroplating silver resin as a modifier, thereby effectively improving the edge accumulation phenomenon, and uses high-functionality polyurethane acrylate to increase the UV reaction speed and play an auxiliary curing role. Compared with the method of adding high-functional monomers to conventional coatings for curing, the shrinkage is lower, the fluidity is worse, and it is not easy to cause edge accumulation. On the other hand, the performance of the coating in all aspects is improved through resin matching - hydroxyl-containing aliphatic polyurethane acrylate is used as the main component of the resin system, and its advantages of excellent leveling and fullness, good plating properties and medium reaction speed are used to replace the large molecular weight 2-functional plating resin in the existing traditional NCVM primer, so as to solve the problems of poor leveling and slow reaction speed of the existing NCVM primer, and give the coating a mirror leveling effect; at the same time, polycarbonate polyurethane acrylate is added as a supplement to the plating performance without affecting the leveling effect of the coating, and can also provide good moisture and heat resistance and toughness for the coating and the coating, and adjust the overall chemical resistance of the coating; and then matched with a specific amount of high-functionality polyurethane acrylate, it greatly improves the curing reaction rate of the coating without affecting the plating property and hardness of the coating.

[0007] As a further preferred embodiment of the above technical solution, the functionality of the hydroxyl-containing aliphatic polyurethane acrylate is 2-4, the hydroxyl value is 80-110 mgKOH / g, and the viscosity is 10000-35000 mPa·s / 25° C. The hydroxyl-containing aliphatic polyurethane acrylate having the above parameters has the characteristics of high solid, low viscosity and high leveling, and is more suitable for the coating system of the present invention.

[0008] As a further preferred embodiment of the above technical solution, the functionality of the high-functionality polyurethane acrylate is 6 or 9, and the viscosity is 1000 Pa·s / 25°C. The functional polyurethane acrylate with the above parameters can increase the UV reaction speed, better play an auxiliary curing role, and has lower shrinkage and worse fluidity than the conventional coating curing method of adding high-functional monomers, and is not easy to cause edge accumulation.

[0009] As a further preferred embodiment of the above technical solution, the functionality of the polycarbon type polyurethane acrylate is 2. Polycarbon type polyurethane acrylate with a functionality of 2 has better plating properties when used as a primer resin, and too high a functionality will result in a hard paint film.

[0010] As a further preferred embodiment of the above technical solution, the TG point of the electroplating silver resin is 85-105° C. The components of the electroplating silver resin are generally cellulose, and the TG point itself is generally high. When used in the UV system of the present invention, the characteristics of its large molecular weight can be utilized to achieve rapid surface drying of the coating and reduce edge accumulation.

[0011] As a further preferred embodiment of the above technical solution, the leveling agent is polydimethylsiloxane / polyether modified polyacrylate. The leveling agent has both leveling and wetting functions, and can adjust long and short wave leveling. Compared with the commonly used leveling agents, the auxiliary ingredients are polyacrylate modified with silicone and polyether macromolecular monomers. The polyether modified structure will increase the surface tension, while the silicone modified structure will slightly reduce the surface tension. The combination of the two will not affect the surface tension of the coating. Therefore, the coating film is not easy to form a surface tension gradient during the solvent volatilization process, which can effectively inhibit the edge accumulation phenomenon.

[0012] As a further preferred embodiment of the above technical solution, the photoinitiator includes at least one of 1-hydroxycyclohexyl phenyl ketone and benzophenone.

[0013] As a further preferred embodiment of the above technical solution, the diluent is composed of the following components in parts by mass: 10-15 parts of ethyl acetate, 5-8 parts of butyl acetate, 5-8 parts of propylene glycol methyl ether acetate and 3-5 parts of diacetone alcohol. Through the composition of the above diluent, the surface tension of the diluent is greater than the surface tension of other components, and the generation of the surface tension gradient can be significantly reduced when the solvent evaporates, thereby improving the edge accumulation phenomenon. At the same time, the diluent needs to have a volatilization gradient. Too fast or too slow will cause paint film defects. The combination of the above diluents ensures that the volatilization will not be too fast or too slow.

[0014] Based on the same technical concept, the present invention also provides a method for preparing the above-mentioned mirror leveling UV coating, comprising the following steps: S1, mixing the photoinitiator with the first part of the diluent to obtain system A; S2, mixing the hydroxyl-containing aliphatic polyurethane acrylate, polycarbonate polyurethane acrylate, high-functionality polyurethane acrylate and electroplating silver resin with the second part of the diluent to obtain system B; S3, adding the system A into the system B, mixing evenly, then adding the leveling agent and the remaining diluent, and mixing evenly to obtain the mirror leveling UV coating.

[0015] As a further preferred embodiment of the above technical solution, in S1, the mass ratio of the photoinitiator to the first part of the diluent is 1:3; in S2, the mass of the second part of the diluent accounts for 1 / 4 to 1 / 3 of the total mass of the diluent.

[0016] As a further preferred embodiment of the above technical solution, in S1, the photoinitiator is added to the diluent, immersed for 20 minutes, and then stirred and mixed for 10 to 15 minutes to obtain a mixed system A.

[0017] As a further preferred embodiment of the above technical solution, in S2, the hydroxyl-containing aliphatic polyurethane acrylate, polycarbonate polyurethane acrylate, high-functionality polyurethane acrylate and electroplating silver resin A are preheated and then mixed with the diluent, the preheating temperature is 60~70°C, and the preheating time is 3~4h; the mixing temperature is 40~50°C, the mixing stirring speed is 950~1050r / min, and the mixing time is 25~30min.

[0018] As a further preferred embodiment of the above technical solution, in S3, the mixing stirring speed of system A and system B is 500-600 r / min, and the mixing time is 25-30 min; after adding the leveling agent and the diluent, the mixing speed is 500-600 r / min, and the mixing time is 15-20 min.

[0019] Based on the same technical concept, the present invention also provides an application of the mirror-leveling UV coating described in the above technical solution, wherein the mirror-leveling UV coating is used to form a coating on the surface of an electronic product housing.

[0020] As a further preferred embodiment of the above technical solution, the mirror-leveling UV coating is applied to the surface of the electronic product housing by vertical spraying. During the coating, the electronic product housing is placed vertically to the ground.

[0021] The present invention has the following beneficial effects: (1) The mirror-leveling UV coating of the present invention suppresses the generation of a surface tension gradient between the edge and the middle of the workpiece during the flash-drying process of the paint film by optimizing the combination of resin, diluent, and additives, thereby effectively improving the edge accumulation phenomenon. On the other hand, it obtains other properties such as good leveling, moisture and heat resistance, and toughness, thereby obtaining a UV coating with a mirror-leveling effect, good tolerance, and toughness, which is not prone to edge accumulation at the edge of the workpiece. (2) The mirror-leveling UV coating of the present invention has a simple preparation process, low requirements on production equipment, and is suitable for large-scale industrial production; (3) The mirror-leveling UV coating of the present invention can be directly used for coating the housing of electronic equipment. By combining the coating with the vertical spray coating process, a perfect mirror-like coating without edge accumulation can be directly obtained on the surface of the housing of the electronic equipment. Compared with the existing process, the complexity of the process and the production cost of this application are greatly reduced. DETAILED DESCRIPTION

[0022] The present invention is described in detail below in conjunction with the embodiments thereof, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0023] In some preferred embodiments of the present invention, the functionality of the hydroxyl-containing aliphatic polyurethane acrylate is 2-4, the hydroxyl value is 80-110 mgKOH / g, and it has the characteristics of fast curing speed, good leveling and fullness, excellent water boiling resistance and weather resistance, etc. When the addition amount is 30-45 parts by weight, as the main resin of the system, the paint film can have a mirror leveling effect. The hydroxyl-containing aliphatic polyurethane acrylate is selected from one or more of BW8214 of Bahe New Materials and W2815 of Wuxing New Materials (BW8214 is selected in each embodiment).

[0024] In some preferred embodiments of the present invention, the high-functionality polyurethane acrylate resin has a viscosity of 1000-2000 mPa.s (25°C), a functionality of 6 or 9, and an addition amount of 3-5 parts. It has little effect on the surface hardness of the paint film after curing, does not affect the plating property of the primer, but greatly improves the curing reaction rate of the primer. The high-functionality polyurethane acrylate resin is selected from one or more of 6145-100 of Changxing Chemical and CN9010NS of Sartomer of the United States (CN9010NS is selected in each embodiment).

[0025] In some preferred embodiments of the present invention, polycarbon type polyurethane acrylate has the characteristics of resistance to moisture, heat and water boiling, has a functionality of 2, good flexibility, can assist the main resin to improve the plating performance of the system, and when added in an amount of 8 to 15 parts by weight, it can well adjust the toughness of the coating without affecting the mirror leveling effect of the coating, while improving the environmental performance of the coating. The polycarbon type polyurethane acrylate is selected from one or more of Shanghai Difeng DF6372, Zhanxin 1114, Dongguan Fengjin FJ228, and American Sartomer CN9001NS (CN9001NS is selected in each embodiment).

[0026] In some preferred embodiments of the present invention, the electroplating silver resin has a large molecular weight, and its main component is resin cellulose, which has the characteristics of accelerating the release of solvents in the paint film, good compatibility with the UV system, and utilizing its large molecular weight and poor fluidity to well inhibit the occurrence of edge accumulation. The electroplating silver resin is selected from Shenzhen Xiyu A-308W.

[0027] In some embodiments of the present invention, the leveling agent is a polyether and silicone double modified polyacrylate, which has both leveling and wetting properties, and can adjust long and short wave leveling without affecting the surface tension of the coating. Therefore, the coating does not form a surface tension gradient during the solvent volatilization process, and the edge accumulation phenomenon can be effectively suppressed. The leveling agent is purchased from BYK, Germany, and the model is BYK-3558.

[0028] Embodiment 1: The mirror-leveling UV coating of this embodiment includes the components in parts by weight shown in Table 1.

[0029] The mirror-leveling UV coating of this embodiment is prepared by the following method: S1. Add the photoinitiator to the first part of the diluent (mass ratio of 1:3) and soak for 20 minutes, then stir and mix for 15 minutes to obtain system A for standby use; S2. Preheat the hydroxyl-containing aliphatic polyurethane acrylate, polycarbonate polyurethane acrylate, high-functionality polyurethane acrylate, and electroplated silver resin to 70°C, keep warm for 3-4 hours, and then stir and mix with the second part of the diluent (accounting for 1 / 3 of the total mass of the diluent) at 50°C and 1000 r / min for 30 minutes to obtain system B; S3. Add system A to system B and mix at 600 r / min for 30 min; S4. Add the leveling agent and the remaining diluent to the system obtained in step S3, and mix at 600 r / min for 20 min to obtain the mirror-leveling UV coating of this embodiment.

[0030] The mirror-leveling UV coating of this embodiment can be used to form a coating on the surface of an electronic product housing. The specific application method includes the following steps: D1. Primer is sprayed on the surface of electronic products (SP100-00053 produced by Matsui Chemical is selected in each embodiment), the coating method is vertical spraying (the material is perpendicular to the ground), the coating film thickness is 10μm, and leveling is performed at 55°C for 6 minutes; D2. Spray the mirror-leveling UV coating of this embodiment on the surface of the Primer after leveling. The coating method is vertical spraying (the material is vertical to the ground), the coating film thickness is 35μm, and leveling is carried out at 60℃ for 8min; then spray at 800mJ / cm 2 Curing and drying under energy-efficient UV light; D3. A vacuum coating process is performed on the vacuum coating primer after solidification and drying, the coating material is indium, and the coating thickness is about 30 nanometers; D4. Spray vacuum coating intermediate paint (SP120-20013-1 produced by Songjing Chemical Co., Ltd. is used in all examples) on the surface of vacuum coating primer after coating. The coating method is flat spraying (the material is parallel to the ground), the coating film thickness is 7μm, and it is leveled at 65℃ for 8min; then spray at 500mJ / cm 2 Curing and drying under energy-efficient UV light; D5. Spray vacuum coating topcoat (SP130-30070 produced by Songjing Chemical Co., Ltd. is used in all embodiments) on the vacuum coating midcoat after solidification and drying. The coating method is flat spraying (the material is parallel to the ground). The coating film thickness is 25 μm. First, leveling at 70°C for 8 minutes, and then at 1200 mJ / cm 2 Curing under high energy UV light.

[0031] Embodiment 2: The mirror-leveling UV coating of this embodiment includes the components in parts by weight shown in Table 1.

[0032] The preparation method of the mirror-leveling UV coating of this embodiment is the same as that of Embodiment 1.

[0033] The mirror-leveling UV coating of this embodiment can be used to form a coating on the surface of the housing of an electronic product, and the specific application method is the same as that of Embodiment 1.

[0034] Embodiment 3: The mirror-leveling UV coating of this embodiment includes the components in parts by weight shown in Table 1.

[0035] The preparation method of the mirror-leveling UV coating of this embodiment is the same as that of Embodiment 1.

[0036] The mirror-leveling UV coating of this embodiment can be used to form a coating on the surface of the housing of an electronic product, and the specific application method is the same as that of Embodiment 1.

[0037] Embodiment 4: The mirror-leveling UV coating of this embodiment includes the components in parts by weight shown in Table 1.

[0038] The preparation method of the mirror-leveling UV coating of this embodiment is the same as that of Embodiment 1.

[0039] The mirror-leveling UV coating of this embodiment can be used to form a coating on the surface of the housing of an electronic product, and the specific application method is the same as that of Embodiment 1.

[0040] Embodiment 5: The mirror-leveling UV coating of this embodiment includes the components in parts by weight shown in Table 1.

[0041] The preparation method of the mirror-leveling UV coating of this embodiment is the same as that of Embodiment 1.

[0042] The mirror-leveling UV coating of this embodiment can be used to form a coating on the surface of the housing of an electronic product, and the specific application method is the same as that of Embodiment 1.

[0043] Embodiment 6: The mirror-leveling UV coating of this embodiment includes the components in parts by weight shown in Table 1.

[0044] The preparation method of the mirror-leveling UV coating of this embodiment is the same as that of Embodiment 1.

[0045] The mirror-leveling UV coating of this embodiment can be used to form a coating on the surface of the housing of an electronic product, and the specific application method is the same as that of Embodiment 1.

[0046] Table 1. Component ratios of the mirror leveling UV coatings of Examples 1 to 6 (parts by mass)

[0047] Comparative Example 1: The coating of this comparative example is different from that of Example 6 only in that 10 parts by weight of a conventional 2-functionality coatable polyurethane acrylic resin (trade name: Japan Synthetic UV-3000B) is used to replace 10 parts by weight of aliphatic polyurethane acrylate with hydroxyl groups in Example 6; the proportions of other components, preparation methods, and application methods are the same as those in Example 6.

[0048] Comparative Example 2: The coating of this comparative example is different from that of Example 6 only in that 5 parts by mass of the high-functionality polyurethane acrylate in Example 6 are replaced by 5 parts by mass of a high-functional monomer (trade name: Sadomar SR399), and the proportions, preparation methods, and application methods of the remaining components are the same as those of Example 6.

[0049] Comparative Example 3: The coating of this comparative example is different from that of Example 6 only in that 2 parts by weight of polyether and silicone dual-modified polyacrylate additives in Example 6 are replaced by 2 parts by weight of polyacrylate solution (trade name BYK358N) in this comparative example, and the proportions, preparation methods and application methods of the remaining components are the same as those of Example 6.

[0050] The coatings of the embodiments and comparative examples were tested for their appearance leveling and edge accumulation effects, high temperature and high humidity resistance, and cylindrical bending performance when applied to the middle frame of a smartphone. The test method is shown below, and the specific results are shown in Table 2.

[0051] The leveling and edge accumulation effects are judged and compared visually.

[0052] High temperature and high humidity resistance performance test method: The product is placed in a 65°C, 95%RH environment for 168 hours. It is qualified if there is no obvious discoloration or blistering and the adhesion reaches 4B or above.

[0053] Cylindrical bending test method: Cut the workpiece to be tested into flat samples, test the cracking size of the paint film, and the diameters of the cylindrical shafts are 40mm and 50mm respectively.

[0054] Table 2. Performance test results of the paint films formed by various embodiments and comparative examples

[0055] Table 3 Results: The leveling and edge accumulation effects of the paint films obtained in Examples 1 to 6 are balanced, thanks to the adjustment of the high-solid low-viscosity system and the optimization of the surface tension gradient combined with the vertical spraying process. Under the optimization of multiple factors, the expected goal was achieved. The reason why the cylindrical bending of Example 6 is relatively poor is that the paint film is too hard due to excessive high-functional resin.

[0056] Compared with Example 6, Comparative Example 1 uses a conventional 2-functionality coating polyurethane acrylic resin (trade name Japan Synthetic UV-3000B) to partially replace the hydroxyl-containing aliphatic polyurethane acrylate in Example 6. The introduction of high molecular weight polyurethane affects the surface leveling effect of the primer and causes fine orange lines, which proves that the conventional vacuum coating primer system cannot meet the high leveling requirements.

[0057] Compared with Example 6, Comparative Example 2 uses a high-functional monomer (trade name Sadomar SR399) to replace the high-functionality polyurethane acrylate in Example 6, so that the fluidity of the vacuum plating primer is increased, and the flow of the paint film is accelerated during the baking process, resulting in edge accumulation.

[0058] Compared with Example 6, Comparative Example 3 uses a conventional polyacrylate solution (trademark number BYK358N) to replace the polyether and silicone dual-modified polyacrylate additives in Example 6. There is no effect on the short-wave leveling of the paint film, there are small waves as a whole, and the compatibility with the system is poor. After the high temperature and high humidity test, the whitening is poor.

[0059] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and changes obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

[0060] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A mirror leveling UV coating, characterized in that: The composition comprises the following components in parts by weight: 30~45 parts of hydroxyl-containing aliphatic polyurethane acrylate, 8~15 parts of polycarbonate polyurethane acrylate, 3~5 parts of high-functionality polyurethane acrylate, 3~5 parts of electroplating silver resin, 2~5 parts of photoinitiator, 1~2 parts of leveling agent and 35~45 parts of diluent.

2. The mirror-leveling UV coating according to claim 1, characterized in that: The functionality of the hydroxyl-containing aliphatic polyurethane acrylate is 2-4, the hydroxyl value is 80-110 mgKOH / g, and the viscosity is 10000-35000 mPa·s / 25°C.

3. The mirror-leveling UV coating according to claim 1, characterized in that: The high-functionality polyurethane acrylate has a functionality of 6 or 9 and a viscosity of 1000 Pa·s / 25°C.

4. The mirror-leveling UV coating according to claim 1, characterized in that: The functionality of the polycarbonate type polyurethane acrylate is 2.

5. The mirror-leveling UV coating according to claim 1, characterized in that: The TG point of the electroplated silver resin is 85-105°C.

6. The mirror-leveling UV coating according to any one of claims 1 to 5, characterized in that: The leveling agent is polydimethylsiloxane / polyether modified polyacrylate; the photoinitiator includes at least one of 1-hydroxycyclohexyl phenyl ketone and benzophenone; the diluent is composed of the following components in parts by mass: 10 to 15 parts of ethyl acetate, 5 to 8 parts of butyl acetate, 5 to 8 parts of propylene glycol methyl ether acetate and 3 to 5 parts of diacetone alcohol.

7. A method for preparing the mirror-leveling UV coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, mixing the photoinitiator with the first part of the diluent to obtain system A; S2, mixing the hydroxyl-containing aliphatic polyurethane acrylate, polycarbonate polyurethane acrylate, high-functionality polyurethane acrylate and electroplating silver resin with the second part of the diluent to obtain system B; S3, adding the system A into the system B, mixing evenly, then adding the leveling agent and the remaining diluent, and mixing evenly to obtain the mirror leveling UV coating.

8. The method for preparing the mirror-leveling UV coating according to claim 7, characterized in that: In S1, the mass ratio of the photoinitiator to the first part of the diluent is 1:3; in S2, the mass of the second part of the diluent accounts for 1 / 4 to 1 / 3 of the total mass of the diluent.

9. The method for preparing the mirror-leveling UV coating according to claim 7, characterized in that: In S2, the hydroxyl-containing aliphatic polyurethane acrylate, polycarbonate polyurethane acrylate, high-functionality polyurethane acrylate and electroplating silver resin A are preheated and then mixed with the diluent, the preheating temperature is 60-70°C, and the preheating time is 3-4h; the mixing temperature is 40-50°C, the mixing stirring speed is 950-1050r / min, and the mixing time is 25-30min.

10. An application of the mirror-leveling UV coating according to any one of claims 1 to 6 or the mirror-leveling UV coating prepared by the preparation method according to any one of claims 7 to 9, characterized in that: The mirror-leveling UV coating is used to form a coating on the surface of the electronic product housing; The mirror-leveling UV coating is applied to the surface of the electronic product housing by vertical spraying. During the coating, the electronic product housing is placed vertically to the ground.

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