Efficient antibacterial photocuring powder paint coating and preparation method thereof

Abstract

The invention belongs to the technical field of powder paint coating preparation, and particularly relates to an efficient antibacterial light-cured powder paint coating and a preparation method thereof.The efficient antibacterial light-cured powder paint coating is composed of, by weight, 100 parts of unsaturated light-cured resin, 3-9 parts of long-chain unsaturated quaternary ammonium salt, 3-5 parts of a photoinitiator, 0.1-0.5 part of a polymerization inhibitor, 3-10 parts of filler and 1-2.5 parts of a flatting agent. The preparation process comprises the following steps: uniformly spraying the powder coating on the surface of the substrate through an electrostatic spray gun, then carrying out hot leveling treatment for 25-30 minutes, and finally curing to form a film through ultraviolet irradiation. The long-chain unsaturated quaternary ammonium salt in the system can migrate and be enriched on the surface layer of the coating in a hot leveling stage, is firmly anchored in a coating matrix after being cured, and is difficult to escape, so that the coating is endowed with a lasting and stable antibacterial function.

Description

Technical Field

[0001] This invention belongs to the field of powder coating preparation technology, specifically relating to a high-efficiency antibacterial photocurable powder coating and its preparation method. Background Technology

[0002] Antibacterial powder coatings refer to functional coatings with antibacterial effects formed by powder coating film formation. When bacteria and other microorganisms adhere to the coated product, the antibacterial components in the coating can disrupt the normal metabolism and reproduction of microorganisms through contact, thus inactivating them and achieving the antibacterial purpose. This type of coating imposes the following core requirements on the antibacterial components: First, the antibacterial components must be uniformly dispersed in the coating to ensure overall antibacterial potential; second, the antibacterial components must have a moderate ability to migrate to the coating surface to effectively contact and kill microorganisms; third, the migration ability of the antibacterial components must be controlled within a reasonable range—excessive migration ability can lead to premature precipitation and inactivation of the antibacterial agent, while insufficient migration ability reduces the surface antibacterial efficiency.

[0003] In existing antibacterial technologies, inorganic antibacterial agents, while exhibiting excellent antibacterial effects, are prone to aggregation in the coating matrix and exhibit significant migration and precipitation phenomena. This not only affects the overall antibacterial durability of the coating but also significantly reduces its mechanical properties. Small-molecule organic antibacterial agents, while reducing aggregation problems, suffer from excessive migration capabilities, causing most antibacterial agents to migrate to the coating surface and become ineffective before fully exerting their effects, resulting in poor antibacterial durability. On the other hand, while chemical grafting can fix antibacterial groups onto polymer macromolecular chains and prevent antibacterial agent migration and precipitation, it also leads to the loss of migration ability of the antibacterial groups, causing them to move away from the coating surface. This results in an overall low utilization rate of the antibacterial agent, making it impossible to effectively exert its antibacterial function. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides an antibacterial modification scheme for a photocurable powder coating that can both provide highly efficient antibacterial intervention on the coating surface and prevent the antibacterial agent from becoming ineffective after migration. The photocurable powder coating, by weight, comprises 100 parts of unsaturated photocurable resin, 3-9 parts of long-chain unsaturated quaternary ammonium salt, 3-5 parts of photoinitiator, 0.1-0.5 parts of polymerization inhibitor, 3-10 parts of filler, and 1-2.5 parts of leveling agent.

[0005] Among them, the unsaturated light-curing resin is a light-curing unsaturated acrylate resin, such as UVECOAT3001, UVECOAT3003, UVECOAT9010, Eternal6071, Eternal6172-1, etc.

[0006] Long-chain unsaturated quaternary ammonium salts are acryloyloxy long-chain alkyl quaternary ammonium salts, with the number of repeating units of the long-chain alkyl group being 10 to 18, such as methacryloyloxyethyl dimethyl dodecyl ammonium bromide, methacryloyloxy dodecyl pyridine bromide, etc.

[0007] In this formulation, long-chain unsaturated quaternary ammonium salts are used as antibacterial components. The positively charged quaternary ammonium salt groups bind to the negatively charged bacterial microbial cells through electrostatic attraction, thereby inactivating them and achieving an antibacterial effect.

[0008] Furthermore, after spraying, UV-cured powder coatings must be kept heated for a sufficient period of time to melt, soften, and fully level before being cured and set by light. Otherwise, problems such as insufficient curing, rough morphology, and poor surface quality will occur. During the heat leveling process before curing, small-molecule antibacterial agents in the coating are easily driven by the heat effect to migrate to the coating surface, thus causing premature failure of the antibacterial active ingredients.

[0009] To address this, this solution selects long-chain unsaturated quaternary ammonium salts as monomer molecules for the antibacterial agent. During the heat leveling process after powder coating application, the long-chain unsaturated quaternary ammonium salts dispersed in the coating system tend to migrate towards the coating surface due to continuous heating. Simultaneously, the long alkyl chains in their molecular structure easily form entanglements with the macromolecular chains of the matrix resin (i.e., the unsaturated UV-curable resin), thus exerting a continuous binding effect on the antibacterial agent molecule. During migration under this binding effect, the long-chain unsaturated quaternary ammonium salts exhibit significantly different behavior from small-molecule antibacterial agents—even if sufficient migration is allowed, they ultimately only reach a precise equilibrium state of "migrating as close as possible to the coating surface, but unable to truly detach from the coating matrix." Subsequently, through the UV curing process, these long-chain unsaturated quaternary ammonium salts utilize the carbon-carbon double bonds in their molecules to achieve sufficient chemical bonding with the coating matrix resin, thereby stably anchoring themselves in their current position, effectively preventing subsequent migration and loss, and ultimately achieving long-lasting antibacterial function.

[0010] Furthermore, since the long-chain unsaturated quaternary ammonium salts in the coating undergo photopolymerization while entangled with the matrix polymer, the individual quaternary ammonium salt molecular chains are likely still surrounded and supported by the cross-linked network structure of the matrix polymer chains after curing. Although there is considerable migration and concentration of quaternary ammonium salt molecules near the coating surface during photocuring, the direct polymerization and connection between multiple quaternary ammonium salt molecular chains is still relatively rare. This characteristic helps maintain the structural stability of the coating surface—because the quaternary ammonium salt molecular chain contains only one carbon-carbon double bond, if its molecular chains are directly polymerized and connected, an effective cross-linked network structure cannot be formed; and when the proportion of such non-cross-linked network polymer structures on the coating surface is too high, it will significantly affect the overall stability of the coating in use.

[0011] The photoinitiator is used in an amount of 3-5 parts, which is slightly higher than the proportion of photoinitiators added in many existing photocurable powder coatings. This design is mainly based on the following two considerations: First, the photoinitiator is a small molecule additive, and in the film formation process including the heat leveling step, it also has a potential tendency to migrate to the coating surface; Second, this scheme is based on the structural characteristics of long-chain unsaturated quaternary ammonium salt antibacterial agents (the long alkyl chains in their molecular structure are entangled with the matrix resin, which can limit migration), and is confident that the antibacterial agent will not actually migrate out or detach from the coating matrix during the heat leveling stage. To promote the migration of as much long-chain unsaturated quaternary ammonium salt antibacterial agent in the coating as possible and bring it closer to the coating surface, this scheme achieves this goal by extending the heat leveling time before light irradiation; however, during this extended heat leveling process, the small molecule photoinitiator always faces the risk of migrating out of the coating system and becoming ineffective. Therefore, it is necessary to appropriately increase the initial addition amount of photoinitiator (small molecule additive) to ensure that the photoinitiator content in the subsequent coating is maintained above the minimum threshold required for effective curing, and to avoid the problem of insufficient curing of the coating due to insufficient photoinitiator.

[0012] Among the remaining components, fillers such as talc, titanium dioxide, and hydrophobic fumed silica can be selected; polymerization inhibitors such as p-hydroxyanisole can be used; and leveling agents such as propylene-based dimethyl silicone oil can be used.

[0013] This invention also provides a method for preparing the above-mentioned high-efficiency antibacterial photocurable powder coating.

[0014] First, prepare the powder coating: Mix unsaturated UV-curable resin, long-chain unsaturated quaternary ammonium salt, photoinitiator, polymerization inhibitor, and leveling agent in a high-speed disperser for 5 min to 10 min, then melt-blend and granulate through a twin-screw extruder (so that the long-chain unsaturated quaternary ammonium salt and other components are fully dispersed in the unsaturated UV-curable matrix resin), and then pulverize the resulting granules to 30 µm to 50 µm.

[0015] Next, the film-forming process is performed: the powder coating is evenly sprayed onto the substrate surface using an electrostatic spray gun, with a coating amount of 90 g / m². 2 ~180g / m 2 Then, after heat leveling at 100℃~110℃ for 25min~30min, UV curing is performed for 3min~5min, with an intensity of 80W / cm²~130W / cm².

[0016] In existing powder coating UV curing processes, the purpose of heat leveling is primarily to achieve a smooth surface after the coating melts. Therefore, the heat leveling duration in conventional processes is usually short, generally controlled within 10 minutes, and in some cases, even as short as 5 minutes to achieve sufficient leveling and surface smoothness. However, in this solution, the heat leveling time is specifically set to 20-30 minutes, significantly longer than the settings in existing conventional processes. This design is based on the following technical judgment: This solution is based on the mechanism that "long-chain unsaturated quaternary ammonium salts do not actually migrate, overflow, and detach from the coating matrix during heat leveling, thus preventing failure." By specifically extending the heat leveling time, this promotes the migration of as many long-chain unsaturated quaternary ammonium salts as possible to the coating surface, thereby improving the utilization rate of the antibacterial agent in the coating.

[0017] The heat leveling time is 25-30 minutes. This duration is designed to ensure that the long-chain unsaturated quaternary ammonium salt can migrate and accumulate near the coating surface, while preventing it from overflowing the system due to excessive diffusion, thus laying the foundation for surface orientation anchoring in the subsequent UV curing process.

[0018] Therefore, it is necessary to introduce a polymerization inhibitor into the formulation. This inhibitor can effectively suppress the prepolymerization reaction of unsaturated bonds caused by high temperatures during the heat leveling stage, preventing the quaternary ammonium salt antibacterial agent from being prematurely embedded or fixed within the coating, thus preventing the molecular chain segments from losing their ability to migrate to the surface. Correspondingly, to overcome the inhibitory effect of the polymerization inhibitor on the photocuring reaction, the duration of subsequent photocuring needs to be appropriately extended to ensure that the coating system achieves sufficient cross-linking and curing. Detailed Implementation

[0019] Example 1

[0020] Based on weight parts, 75 parts by weight of UVECOAT3003, 25 parts by weight of UVECOAT9010, 5 parts by weight of methacryloyloxyethyl dimethyl dodecyl ammonium bromide (structure shown below), 4.5 parts by weight of photoinitiator Irgacure184, 0.3 parts by weight of polymerization inhibitor p-hydroxyanisole, 3 parts by weight of rutile titanium dioxide pigment, and 1.2 parts by weight of leveling agent BYK3576 were dispersed and mixed in a high-speed disperser for 10 minutes. The mixture was then melt-blended and extruded through a twin-screw extruder at 85℃~90℃, cooled, and granulated into particles with a diameter of 500µm. The resulting particles were pulverized, sieved, and powder with a particle size of 30µm~50µm was retained, which is the powder coating. This powder coating was then uniformly sprayed onto the surface of medium-density fiberboard (MDF) (the surface of the board is flat and clean) using an electrostatic spray gun, with a spraying amount of 120g / m². 2 Then, after heat leveling at 105℃ for 25 minutes, the coating is further cured by ultraviolet irradiation with a mercury lamp for 3.5 minutes, with an irradiation intensity of 90W / cm² and a vertical irradiation distance of 10cm.

[0021]

[0022] Example 2

[0023] Based on parts by weight, 70 parts by weight of UVECOAT3001, 30 parts by weight of UVECOAT9010, 6 parts by weight of methacryloyloxyethyl dimethyl dodecyl ammonium bromide, and 5 parts by weight of photoinitiator Irgacure are included. 184. 0.5 parts by weight of polymerization inhibitor p-hydroxyanisole, 2.5 parts by weight of rutile titanium dioxide pigment, 2 parts by weight of talc, 0.25 parts by weight of hydrophobic fumed silica, and 2 parts by weight of leveling agent BYK3576 were dispersed and mixed in a high-speed disperser for 10 minutes. The mixture was then melt-blended and extruded through a twin-screw extruder at 85℃~90℃, cooled, and granulated into granules with a particle size of 500µm. The resulting granules were pulverized, sieved, and powder with a particle size of 30µm~50µm was retained, which is the powder coating. This powder coating was then uniformly sprayed onto the surface of medium-density fiberboard (MDF) (the surface of the board is flat and clean) using an electrostatic spray gun, with a spraying amount of 130g / m². 2 Then, after heat leveling at 100℃ for 30 minutes, the coating is further cured by ultraviolet irradiation with a mercury lamp for 5 minutes, with an irradiation intensity of 90W / cm² and a vertical irradiation distance of 10cm.

[0024] Example 3

[0025] Based on parts by weight, 70 parts by weight of UVECOAT3003, 30 parts by weight of UVECOAT9010, 4.5 parts by weight of methacryloyloxyethyl dimethyl dodecyl ammonium bromide, and 3.5 parts by weight of the photoinitiator Irgacure are included. 184 parts by weight of polymerization inhibitor p-hydroxyanisole, 4.75 parts by weight of rutile titanium dioxide pigment, 0.25 parts by weight of hydrophobic fumed silica, and 1.7 parts by weight of leveling agent BYK3576 were dispersed and mixed in a high-speed disperser for 10 minutes. The mixture was then melt-blended and extruded through a twin-screw extruder at 85℃~90℃, cooled, and granulated into granules with a particle size of 500µm. The resulting granules were pulverized, sieved, and powder with a particle size of 30µm~50µm was retained, which is the powder coating. This powder coating was then uniformly sprayed onto the surface of medium-density fiberboard (MDF) (the surface of the board should be flat and clean) using an electrostatic spray gun at a coating amount of 120g / m². 2 After being heat-flowed at 100℃ for 28 minutes, the coating was further cured by ultraviolet irradiation with a mercury lamp for 4 minutes, with an irradiation intensity of 90W / cm² and a vertical irradiation distance of 10cm.

[0026] Blank comparison example

[0027] The powder coating does not contain antibacterial agents; all other components and procedures are the same as in Example 1.

[0028] Based on weight parts, 75 parts by weight of UVECOAT3003, 25 parts by weight of UVECOAT9010, 4.5 parts by weight of photoinitiator Irgacure 184, 0.3 parts by weight of polymerization inhibitor p-hydroxyanisole, 3 parts by weight of rutile titanium dioxide pigment, and 1.2 parts by weight of leveling agent BYK3576 were dispersed and mixed in a high-speed disperser for 10 minutes. The mixture was then melt-blended and extruded through a twin-screw extruder at 85℃~90℃, cooled, and granulated into particles with a diameter of 500µm. The resulting particles were pulverized, sieved, and powder with a particle size of 30µm~50µm was retained, which is the powder coating. This powder coating was then uniformly sprayed onto the surface of medium-density fiberboard (MDF) (the surface of the board is flat and clean) using an electrostatic spray gun, with a spraying amount of 120g / m². 2 Then, after heat leveling at 105℃ for 25 minutes, the coating is further cured by ultraviolet irradiation with a mercury lamp for 3.5 minutes, with an irradiation intensity of 90W / cm² and a vertical irradiation distance of 10cm.

[0029] Comparative Example 1

[0030] The "methacryloyloxyethyl dimethyl dodecyl ammonium bromide" in the powder coating was replaced with an equimolar amount of "methacryloyloxyethyl trimethyl ammonium chloride," and the heat leveling time after powder coating application was shortened to 10 minutes. All other components and operations remained the same as in Example 1.

[0031] Based on weight parts, 75 parts by weight of UVECOAT3003, 25 parts by weight of UVECOAT9010, 2.5 parts by weight of methacryloyloxyethyltrimethylammonium chloride (structure shown below), 4.5 parts by weight of photoinitiator Irgacure 184, 0.3 parts by weight of polymerization inhibitor p-hydroxyanisole, 3 parts by weight of rutile titanium dioxide pigment, and 1.2 parts by weight of leveling agent BYK3576 were dispersed and mixed in a high-speed disperser for 10 minutes. The mixture was then melt-blended and extruded through a twin-screw extruder at 85℃~90℃, cooled, and granulated into granules with a particle size of 500µm. The resulting granules were pulverized, sieved, and powder with a particle size of 30µm~50µm was retained, which is the powder coating. This powder coating was then uniformly sprayed onto the surface of medium-density fiberboard (MDF) (the surface of the board is flat and clean) using an electrostatic spray gun, with a spraying amount of 120g / m². 2 Then, after heat leveling at 105℃ for 10 minutes, the coating is further cured by ultraviolet irradiation with a mercury lamp for 3.5 minutes, with an irradiation intensity of 90W / cm² and a vertical irradiation distance of 10cm.

[0032]

[0033] Comparative Example 2

[0034] The only difference is that the "methacryloyloxyethyl dimethyl dodecyl ammonium bromide" in the powder coating is replaced with an equimolar amount of "methacryloyloxyethyl trimethyl ammonium chloride," while the other components and operations are the same as in Example 1.

[0035] Based on weight parts, 75 parts by weight of UVECOAT3003, 25 parts by weight of UVECOAT9010, 2.5 parts by weight of methacryloyloxyethyltrimethylammonium chloride, 4.5 parts by weight of photoinitiator Irgacure 184, 0.3 parts by weight of polymerization inhibitor p-hydroxyanisole, 3 parts by weight of rutile titanium dioxide pigment, and 1.2 parts by weight of leveling agent BYK3576 were dispersed and mixed in a high-speed disperser for 10 minutes. The mixture was then melt-blended and extruded through a twin-screw extruder at 85℃~90℃, cooled, and granulated into granules with a particle size of 500µm. The resulting granules were pulverized, sieved, and powder with a particle size of 30µm~50µm was retained, which is the powder coating. This powder coating was then uniformly sprayed onto the surface of medium-density fiberboard (MDF) (the surface of the board is flat and clean) using an electrostatic spray gun, with a spraying amount of 120g / m². 2 Then, after heat leveling at 105℃ for 25 minutes, the coating is further cured by ultraviolet irradiation with a mercury lamp for 3.5 minutes, with an irradiation intensity of 90W / cm² and a vertical irradiation distance of 10cm.

[0036] Comparative Example 3

[0037] The only difference is that the heat leveling time after powder coating is shortened to 10 minutes; all other components and operations are the same as in Example 1.

[0038] By weight, 75 parts UVECOAT3003, 25 parts UVECOAT9010, 5 parts methacryloyloxyethyl dimethyl dodecyl ammonium bromide, 4.5 parts photoinitiator Irgacure 184, 0.3 parts polymerization inhibitor p-hydroxyanisole, 3 parts rutile titanium dioxide pigment, and 1.2 parts leveling agent BYK3576 were dispersed and mixed in a high-speed disperser for 10 minutes. The mixture was then melt-blended and extruded through a twin-screw extruder at 85℃~90℃, cooled, and granulated into particles with a diameter of 500µm. The resulting particles were pulverized, sieved, and powder with a particle size of 30µm~50µm was retained, which is the powder coating. This powder coating was then uniformly sprayed onto the surface of medium-density fiberboard (MDF) (the surface of the board is flat and clean) using an electrostatic spray gun at a coating amount of 120g / m². 2Then, after heat leveling at 105℃ for 10 minutes, the coating is further cured by ultraviolet irradiation with a mercury lamp for 3.5 minutes, with an irradiation intensity of 90W / cm² and a vertical irradiation distance of 10cm.

[0039] After the coatings obtained in each embodiment, blank control, and comparative embodiment were left to stand indoors for 24 hours, antibacterial durability tests were conducted according to the provisions of 6.6 and Appendix A of "HG / T 3950-2007 Antibacterial Coatings". The sample size was 50mm × 50mm. Before inoculation with the bacterial agent, the sample surface was wiped and cleaned with alcohol, rinsed with water, dried with filter paper, and then irradiated under a UV sterilizing lamp for 5 minutes. The amount of test bacterial solution dripped onto the surface of each sample was 0.4mL (concentration of 8 × 10⁻⁶). 5 (CUF / mL approximately), the washed solution after incubation was then inoculated into nutrient agar (NA) medium, and the incubation time was 48 h. The results are shown in Table 1 (average of three parallel samples):

[0040] Table 1

[0041] As shown in Table 1, the molecular size and thermal flux length of the organic antibacterial agent in Comparative Example 1 are close to those of the prior art. In comparison, this solution ultimately demonstrates more ideal antibacterial durability because the organic antibacterial agent methacryloyloxyethyl dimethyl dodecyl ammonium bromide selected in this solution has a long chain structure that is always entangled with the matrix resin chain segment, thereby effectively inhibiting the antibacterial agent from easily detaching from the coating matrix after migrating to the coating surface, so as to better maintain the antibacterial properties of the coating.

[0042] Even though Comparative Example 1 (including subsequent Comparative Example 3) also subjected the coating to photocuring treatment, causing the carbon-carbon double bonds on these small molecule antibacterial agents to polymerize, the binding between the small antibacterial agent molecules and the coating matrix is ​​relatively weak. As a result, the detachment of the migrated small antibacterial agent molecules from the matrix is ​​more obvious. Therefore, during photocuring, these small antibacterial agent molecules will more directly polymerize together to form a linear structure, rather than further chemically crosslinking with the matrix. The small antibacterial agent molecules that polymerize together on the coating surface are also prone to detach from the matrix coating as a whole during the pretreatment stage of antibacterial testing.

[0043] In Comparative Example 2, when using a small molecule antibacterial agent, the excessively long heat leveling time resulted in a significant amount of the small molecule antibacterial agent migrating to the coating surface. As it could not maintain effective bonding with the coating matrix resin, a large amount of it detached during the pretreatment stages of the antibacterial test, leading to a significant further deficiency in the antibacterial effect.

[0044] Compared with this solution, in Comparative Example 3, the long-chain antibacterial agent molecules inside the coating did not migrate sufficiently to the surface of the coating before entering the photocuring stage due to the short heat leveling time. This resulted in a small number of antibacterial agent molecules near the surface of the coating and a decrease in antibacterial ability. Of course, this also shows that the long-chain antibacterial agent molecules selected in this solution are indeed hindered during the migration process to the surface of the molten coating when heated, resulting in a slower migration rate. Therefore, a longer heat leveling time is required for sufficient migration.

[0045] The coatings obtained in each embodiment, blank control, and comparative embodiment were subjected to basic performance tests after being left to stand indoors for 24 hours. The results are shown in Table 2 (average of three parallel samples):

[0046] Table 2

[0047] In Table 2, compared to Example 2, due to the excessively long heat leveling time, significantly more small-molecule antibacterial agents migrated to the coating surface. However, because they could not maintain effective bonding with the coating matrix resin, after photocuring, these small antibacterial agent molecules aggregated individually in large quantities instead of further effectively chemically bonding with the matrix. Furthermore, they existed on the coating surface as non-crosslinked linear polymers, making the coating surface significantly more susceptible to damage after salt spray erosion. This experimental phenomenon is consistent with the previous antibacterial results and analysis.

Claims

1. A high-efficiency antibacterial photocurable powder coating, characterized in that: The coating, by weight, comprises: 100 parts of unsaturated photocurable resin, 3-9 parts of long-chain unsaturated quaternary ammonium salt, 3-5 parts of photoinitiator, 0.1-0.5 parts of polymerization inhibitor, 3-10 parts of filler, and 1-2.5 parts of leveling agent.

2. The high-efficiency antibacterial photocurable powder coating as described in claim 1, characterized in that: The unsaturated photocurable resin is one or a combination of several of UVECOAT3001, UVECOAT3003, UVECOAT9010, Eternal6071, and Eternal6172-1.

3. The high-efficiency antibacterial photocurable powder coating as described in claim 1, characterized in that: The long-chain unsaturated quaternary ammonium salts include methacryloyloxyethyl dimethyl dodecyl ammonium bromide and methacryloyloxy dodecyl pyridine bromide.

4. The high-efficiency antibacterial photocurable powder coating as described in claim 1, characterized in that: The filler is one or a combination of several of talc, titanium dioxide, and hydrophobic fumed silica; the polymerization inhibitor is p-hydroxyanisole; and the leveling agent is dimethyl silicone oil containing propylene groups.

5. A method for preparing a high-efficiency antibacterial photocurable powder coating as described in any one of claims 1 to 4, characterized in that: The high-efficiency antibacterial photocurable powder coating is uniformly sprayed onto the substrate surface using an electrostatic spray gun, and then heat-flowed at 100℃~110℃ for 25min~30min before being cured by ultraviolet light.

6. The method for preparing the high-efficiency antibacterial photocurable powder coating as described in claim 5, characterized in that: The spraying amount during spraying is 90g / m². 2 ~180g / m 2 .

7. The method for preparing the high-efficiency antibacterial photocurable powder coating as described in claim 5, characterized in that: The intensity of the UV curing is 80W / cm² to 130W / cm², and the irradiation time is 3min to 5min.

8. The method for preparing the high-efficiency antibacterial photocurable powder coating as described in claim 5, characterized in that: The preparation and processing operation of the high-efficiency antibacterial photocurable powder coating is as follows: after fully mixing and dispersing the unsaturated photocurable resin, the long-chain unsaturated quaternary ammonium salt, the photoinitiator, the polymerization inhibitor, and the leveling agent, the mixture is melt-blended and extruded into granules through a twin-screw extruder, and the resulting granules are then crushed.

9. The method for preparing the high-efficiency antibacterial photocurable powder coating as described in claim 8, characterized in that: The granules are crushed to 30µm to 50µm.

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