Tricresyl phosphate and its preparation and use

Abstract

This invention discloses a conformal coating, its preparation method, and its application, belonging to the field of coatings. The conformal coating comprises the following components by weight percentage: 45%-65% base resin, 25%-50% reactive diluent, 2%-6% initiator, 7%-14% dehydrating agent, and 0%-0.8% additives; wherein the base resin contains NCO groups, and the dehydrating agent includes both chemical and physical dehydrating agents. By ensuring the synergistic effect of the various components in the conformal coating under specific proportions, not only are excellent curing properties guaranteed, resulting in excellent mechanical properties of the coating film, but the conformal coating also has a longer shelf life and service life.

Description

Technical Field

[0001] This invention relates to the field of coatings, and particularly to conformal coatings, their preparation methods, and applications. Background Technology

[0002] Conformal coatings are paints with waterproof, oil-proof, and stain-resistant properties. UV-moisture dual-curing conformal coatings are a common type. They achieve moisture curing by reacting the NCO groups in the coating with a small amount of moisture in the air in areas that cannot be directly cured by ultraviolet light. Because the NCO groups in UV-moisture dual-curing conformal coatings inevitably come into contact with moisture in the air during use and storage, the shelf life of the conformal coating is shortened, and the curing performance of the coating is affected. Therefore, a dehydrating agent is usually added to UV-moisture dual-curing conformal coatings to protect the NCO groups.

[0003] Related technologies incorporate p-methylbenzenesulfonyl isocyanate as a dehydrating agent into conformal coatings. However, when the amount of p-methylbenzenesulfonyl isocyanate added is small, its protective effect on the dehydrating agent is not obvious. If the amount added is large, insoluble substances will precipitate after the reaction, which will adversely affect the weather resistance and mechanical properties of the conformal coating. Therefore, it is difficult to achieve a balance between the amount of p-methylbenzenesulfonyl isocyanate added and the desired performance. Summary of the Invention

[0004] In view of this, the present invention provides a conformal coating, its preparation method and application, which can solve the technical problems existing in related technologies.

[0005] Specifically, the following technical solutions are included:

[0006] On one hand, a conformal coating is provided, the conformal coating comprising the following components in weight percentages: 45%-65% base resin, 25%-50% reactive diluent, 2%-6% initiator, 7%-14% dehydrating agent, and 0%-0.8% additives;

[0007] The matrix resin contains NCO groups, and the dehydrating agent includes chemical dehydrating agents and physical dehydrating agents.

[0008] In some possible implementations, the chemical dehydrating agent accounts for 2%-4% of the mass percentage of the conformal coating, the physical dehydrating agent accounts for 5%-10% of the mass percentage of the conformal coating, and the mass ratio of the chemical dehydrating agent to the physical dehydrating agent is 1:2-3.

[0009] In some possible implementations, the chemical dehydrating agent is p-toluenesulfonyl isocyanate.

[0010] In some possible implementations, the physical dehydrating agent is a molecular sieve dehydrating agent, wherein the static water absorption rate of the molecular sieve dehydrating agent is ≥20%.

[0011] In some possible implementations, the molecular sieve dehydrating agent is selected from at least one of 4A molecular sieve activated powder, 5A molecular sieve activated powder, and 13X molecular sieve activated powder.

[0012] In some possible implementations, the matrix resin is a monofunctional polyurethane acrylate resin.

[0013] In some possible implementations, the reactive diluent is selected from at least one of isoborneol acrylate, isoborneol methacrylate, and hydroxyethyl methacrylate.

[0014] In some possible implementations, the initiator includes at least one of α-hydroxyalkyl ketone photoinitiators and acyl oxide photoinitiators.

[0015] In some possible implementations, the additives include fluorescent whitening agents and leveling agents;

[0016] The fluorescent whitening agent in the conformal coating has a mass percentage greater than 0 and less than or equal to 0.3%.

[0017] The leveling agent has a mass percentage in the conformal coating that is greater than 0 and less than or equal to 0.5%.

[0018] On the other hand, a method for preparing a conformal coating is provided, wherein the conformal coating is as described in any of the above descriptions, and the method for preparing the conformal coating includes:

[0019] The reactive diluent, initiator, and optional additives are mixed evenly to form a first mixture;

[0020] The first mixture, the matrix resin, and optional additives are mixed evenly to form a second mixture;

[0021] The second mixture is mixed evenly with the physical dehydrating agent to form a third mixture;

[0022] The third mixture is mixed evenly with a chemical dehydrating agent to obtain the conformal coating.

[0023] On the other hand, it also provides the application of any of the above-mentioned conformal coatings in circuit boards.

[0024] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0025] The conformal coating provided in this invention has a base resin containing NCO groups, making it a UV-moisture dual-curing conformal coating. By including both chemical and physical dehydrating agents, the physical dehydrating agent is suitable for absorbing moisture from the air introduced during production due to stirring, while the chemical dehydrating agent is suitable for absorbing moisture from the air introduced during storage and use due to frequent opening of the packaging, thus extending the service life of the conformal coating. By ensuring the synergistic effect of the various components in the conformal coating under specific proportions, not only are excellent curing properties and the resulting coating film excellent, but the conformal coating also has a longer shelf life and service life. Detailed Implementation

[0026] Unless otherwise defined, all technical terms used in the embodiments of this invention have the same meaning as commonly understood by those skilled in the art. To make the technical solutions and advantages of this invention clearer, the embodiments of this invention will be described in further detail below.

[0027] Related technologies incorporate p-methylbenzenesulfonyl isocyanate as a dehydrating agent into conformal coatings. However, when the amount of p-methylbenzenesulfonyl isocyanate added is small, its protective effect on the dehydrating agent is not obvious. If the amount added is large, insoluble substances will precipitate after the reaction, which will adversely affect the weather resistance and mechanical properties of the conformal coating. Therefore, it is difficult to achieve a balance between the amount of p-methylbenzenesulfonyl isocyanate added and the desired performance.

[0028] To address the technical problems existing in related technologies, embodiments of the present invention provide a conformal coating, which comprises the following components in weight percentage: 45%-65% base resin, 25%-50% reactive diluent, 2%-6% initiator, 7%-14% dehydrating agent, and 0%-0.8% additives; wherein the base resin contains NCO groups, and the dehydrating agent includes chemical dehydrating agents and physical dehydrating agents.

[0029] The conformal coating provided in this invention has a base resin containing NCO groups, making it a UV-moisture dual-curing conformal coating. By including both chemical and physical dehydrating agents, the physical dehydrating agent is suitable for absorbing moisture from the air introduced during production due to stirring, while the chemical dehydrating agent is suitable for absorbing moisture from the air introduced during storage and use due to frequent opening of the packaging, thus extending the service life of the conformal coating. By ensuring the synergistic effect of the various components in the conformal coating under specific proportions, not only are excellent curing properties and the resulting coating film excellent, but the conformal coating also has a longer shelf life and service life.

[0030] Regarding the mass percentage of each component in conformal coatings, some exemplary embodiments include, but are not limited to, the following:

[0031] For base resins containing NCO groups, their mass percentage in the conformal coating can further be 50%-55%. Exemplarily, the mass percentage of the base resin includes, but is not limited to, the following: 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, etc.

[0032] For reactive diluents, their mass percentage in the conformal coating can further be 30%-40%. Exemplarily, the mass percentage of reactive diluents includes, but is not limited to, the following: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, etc.

[0033] The mass percentage of the initiator in the conformal coating includes, but is not limited to, the following: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, etc.

[0034] For dehydrating agents, the mass percentage of chemical dehydrating agents in conformal coatings is 2%-4%, and the mass percentage of physical dehydrating agents in conformal coatings is 5%-10%, and the mass ratio of chemical dehydrating agents to physical dehydrating agents is 1:2-3, including but not limited to 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, etc.

[0035] For example, the mass percentage of chemical dehydrating agents in conformal coatings includes, but is not limited to, 2%, 2.5%, 3%, 3.5%, etc.

[0036] The mass percentage of physical dehydrating agents in conformal coatings includes, but is not limited to, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, and 9%.

[0037] Excessive addition of chemical dehydrating agent can lead to the precipitation of insoluble substances, affecting the performance of conformal coatings; while insufficient addition will not significantly improve storage stability. This invention uses the aforementioned amount of chemical dehydrating agent in combination with a physical dehydrating agent, effectively solving the above-mentioned technical problems.

[0038] If the amount of physical dehydrating agent added is too small, it will not provide adequate water absorption and protection during the production process, leading to the rapid consumption of the chemical dehydrating agent. Conversely, if the amount of physical dehydrating agent added is too large, it can easily increase the initial viscosity of the conformal coating, resulting in decreased tensile strength and increased brittleness. This invention uses the aforementioned amount of physical dehydrating agent in combination with the chemical dehydrating agent, effectively solving the above-mentioned technical problems.

[0039] Specifically, a mass ratio of chemical dehydrating agent to physical dehydrating agent of 1:2-3 has at least the following effects: excellent water absorption, no additional increase in the viscosity of the conformal coating, less precipitation of dehydrating agent reactants, and no decrease in tensile strength or increase in brittleness. This helps the conformal coating achieve better storage stability and maintain relatively stable properties such as tensile strength, modulus, and brittleness.

[0040] In some examples, a suitable chemical dehydrating agent is p-toluenesulfonyl isocyanate, which can react with residual moisture in the conformal coating and moisture released during physical adsorption during the storage process, thereby protecting the NCO groups of the resin and extending the shelf life of the conformal coating.

[0041] In some examples, some applicable physical dehydrating agents are molecular sieve dehydrating agents with a static water absorption rate ≥20%. The higher the static water absorption rate, the better the water absorption effect of the molecular sieve dehydrating agent.

[0042] During the production of conformal coatings, physical dehydrating agents can adsorb some of the moisture brought in from the air, thereby protecting the NCO groups in the base resin.

[0043] In some examples, the molecular sieve dehydrating agent is selected from at least one of 4A molecular sieve activated powder, 5A molecular sieve activated powder, and 13X molecular sieve activated powder.

[0044] All of the above-mentioned molecular sieve activation powders are fine powders made from zeolite with a particle size ≤50μm. These molecular sieve activation powders have excellent water absorption effects and will not affect the basic performance of conformal coatings.

[0045] In some implementations, the matrix resin is a monofunctional polyurethane acrylate resin containing NCO groups.

[0046] Since the reaction between NCO groups and water requires relatively low conditions and can be carried out at room temperature, the activity of the matrix resin can be reduced by making it a monofunctional resin, thereby improving its storage stability.

[0047] The NCO groups in the matrix resin are 1%-15% by mass, and further 5%-12%, to obtain good moisture curing properties.

[0048] In this embodiment of the invention, polyurethane acrylate resin is selected. Compared with epoxy acrylate or polyester acrylate, polyurethane acrylate resin is more conducive to giving conformal coatings a more balanced overall performance, making them have good flexibility, hardness and weather resistance.

[0049] Polyurethane acrylate resin itself has a high viscosity; excessive content will affect the viscosity of the conformal coating, making application difficult during dispensing, spraying, and brushing. Insufficient polyurethane acrylate resin content will affect the mechanical and chemical properties of the conformal coating, reducing its toughness, making it brittle, and decreasing its chemical resistance. This invention, by maintaining a polyurethane acrylate resin content of 45%-65% by mass, effectively solves the above-mentioned technical problems.

[0050] In some examples, suitable reactive diluents are selected from at least one of isobornyl acrylate (IBOA), isobornyl methacrylate (IBOMA), and hydroxyethyl methacrylate (HEMA).

[0051] By using the above-mentioned types of reactive thinners, and making their mass percentage 25%-50%, the viscosity of the conformal coating is moderate, allowing for smooth application processes such as dispensing, spraying, and brushing.

[0052] In some examples, it is desirable to use low-viscosity, monofunctional acrylate monomers as reactive diluents to reduce viscosity, while minimizing shrinkage. For example, the desired viscosity of the reactive diluent is 5-20 cps (25°C). Isobornyl acrylate (IBOA) and isobornyl methacrylate (IBOMA) can be selected as reactive diluents.

[0053] In some examples, the mass ratio of the functional group resin to the reactive diluent is (50:35)-(55:30), which ensures that the conformal coating has a suitable initial viscosity and a faster UV curing reaction rate so that the curing reaction is complete and the mechanical and chemical properties of the coating film are improved.

[0054] In some examples, the initiator includes at least one of α-hydroxyalkyl ketone photoinitiators and acyl oxide photoinitiators.

[0055] α-Hydroxyalkylone photoinitiators include, but are not limited to, photoinitiator 1173, photoinitiator 184, and photoinitiator 2959, which can help prevent yellowing.

[0056] Acyl oxide initiators include, but are not limited to: photoinitiator 819 and photoinitiator TPO-L, which are capable of deep curing.

[0057] In some examples, the initiator may be selected from α-hydroxyalkyl ketone photoinitiators or acyl oxide photoinitiators.

[0058] In some examples, the initiator may be selected from a combination of α-hydroxyalkyl ketone photoinitiators and acyl oxide photoinitiators, wherein the mass ratio of α-hydroxyalkyl ketone photoinitiators to acyl oxide photoinitiators is (2-4):1.

[0059] Alpha-hydroxyalkyl ketone photoinitiators are typically used for surface curing and exhibit excellent resistance to yellowing, while alkyl oxide photoinitiators are effective for deep curing. By combining the two in the aforementioned ratio, ultraviolet light penetration into the paint film is ensured, resulting in more complete and thorough curing. This leads to improvements in the mechanical properties of the paint film, such as modulus, and its chemical properties.

[0060] In some examples, the conformal coating provided in this embodiment of the invention further includes additives, wherein the additives include optical brighteners and leveling agents. The mass percentage of the optical brightener in the conformal coating is greater than 0 and less than or equal to 0.3%; the mass percentage of the leveling agent in the conformal coating is greater than 0 and less than or equal to 0.5%.

[0061] The purpose of fluorescent whitening agents is to allow devices coated with conformal coatings, such as circuit boards, to be inspected for omissions or missed areas during later repairs. If a blue fluorescence is detected, it indicates that the area is covered with conformal coating, facilitating later inspection and repair.

[0062] The function of leveling agents is to provide leveling and partial slipping of the paint film. For example, leveling agents can be silicone-based leveling agents, such as at least one of BYK 331, BYK 306, and TEGO 450.

[0063] On the other hand, embodiments of the present invention also provide a method for preparing a conformal coating, wherein the conformal coating is as described in any of the above descriptions, and the method for preparing the conformal coating includes:

[0064] The reactive diluent, initiator, and optional additives are mixed evenly to form a first mixture.

[0065] The first mixture, the matrix resin, and optional additives are mixed evenly to form the second mixture.

[0066] The second mixture is then thoroughly mixed with the physical dehydrating agent to form the third mixture.

[0067] Mix the third mixture with the chemical dehydrating agent until homogeneous to obtain the conformal coating.

[0068] Through the above operations, a uniform conformal coating can be prepared.

[0069] In some examples, the stirring speed can be 500 rpm to 600 rpm and the stirring time can be 10 minutes to 15 minutes when the first mixture is formed.

[0070] In some examples, the stirring speed can be 500 rpm to 600 rpm and the stirring time can be 10 minutes to 15 minutes when the second mixture is formed.

[0071] In some examples, the stirring speed can be 1000 rpm to 1500 rpm and the stirring time can be 10 minutes to 30 minutes when forming the third mixture.

[0072] In some examples, when mixing the third mixture with the chemical dehydrating agent, the stirring speed can be 500 rpm to 600 rpm and the stirring time can be 5 minutes to 10 minutes.

[0073] In some examples, after the various components in the conformal coating are thoroughly mixed, they are filtered through a 300-mesh filter and then sealed for storage.

[0074] An exemplary preparation process for conformal coating is shown below:

[0075] Mix the reactive diluent, initiator, and fluorescent whitening agent at 500-600 rpm for 10-15 minutes until homogeneous, forming the first mixture. Mix the first mixture, base resin, and leveling agent at 500-600 rpm for 10-15 minutes until homogeneous, forming the second mixture. Mix the second mixture with a physical dehydrating agent at 1000-1500 rpm for 10-30 minutes until homogeneous, forming the third mixture. Mix the third mixture with a chemical dehydrating agent at 500-600 rpm for 5-10 minutes until homogeneous, and filter through a 300-mesh filter to obtain the conformal coating.

[0076] In some examples, conformal coatings can be applied using the following steps:

[0077] Dilute the conformal coating and butyl acetate at a mass ratio of 100:50-70 to a suitable spraying viscosity. Determine the appropriate viscosity by allowing the coating to flow from a No. 2 cup (25℃) for 10-12 seconds. Apply the coating to the circuit board using a spray gun with a nozzle diameter of 1.0mm-1.5mm. Bake at 50℃-60℃ for 5-8 minutes. Then, use a UV curing machine with a 350nm-370nm mercury lamp at a speed of 2000mJ / cm². 2 -3000mj / cm 2 Energy is used to irradiate and cure the material, resulting in a paint film.

[0078] Furthermore, embodiments of the present invention also provide the application of any of the above-mentioned conformal coatings in circuit boards.

[0079] The conformal coating provided in this invention can be used on circuit boards, that is, as a conformal coating for circuit boards to protect them from environmental corrosion, thereby improving their service life and ensuring safety and reliability. It is understood that by using the conformal coating provided in this invention to form a protective film on the circuit board, the circuit board possesses at least all the advantages of the aforementioned conformal coating.

[0080] In some examples, conformal coating can be applied to the surface of the circuit board by various methods such as brushing, spraying, dipping, or spraying.

[0081] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. In the following embodiments, unless otherwise specified, "%" refers to weight percentage.

[0082] This invention discloses Examples 1-10, and Comparative Examples 1-7, to provide a conformal coating. The formulations of Examples 1-10 are shown in Table 1 below, and the formulations of Comparative Examples 1-7 are shown in Table 2 below. In the tables, " / " indicates "none".

[0083] The types of components involved in the above-mentioned conformal coatings are as follows:

[0084] Matrix resin

[0085] Resin A: Sartoma CN1073NS, a monofunctional polyurethane acrylate with an NCO group content of 9% by mass;

[0086] Resin B: Changxing DR-U227, monofunctional polyurethane acrylate, with NCO groups accounting for 1% by mass;

[0087] Resin C: Sartoma CN9001NS, a monofunctional polyurethane acrylate, free of NCO groups.

[0088] Reactive diluent

[0089] Isobornyl acrylate (IBOA).

[0090] Initiator

[0091] Initiator A: Photoinitiator 1173;

[0092] Initiator B: Photoinitiator 819;

[0093] Initiator C: Photoinitiator TPO-L.

[0094] Dehydrating agent

[0095] Dehydrating agent A, chemical dehydrating agent, p-methylbenzenesulfonyl isocyanate;

[0096] Dehydrating agent B, molecular sieve activation powder 13X, is supplied by Jiangxi Xintao Technology Co., Ltd.

[0097] Additives

[0098] Fluorescent whitening agent, Henan Ruichite OB-1;

[0099] Leveling agent, TEGO 450.

[0100] The preparation steps for each of the above conformal coatings are as follows:

[0101] The reactive diluent, initiator, and fluorescent whitening agent are mixed and stirred at 550 rpm for 15 minutes until homogeneous, forming the first mixture. The first mixture, base resin, and leveling agent are then mixed and stirred at 550 rpm for 15 minutes until homogeneous, forming the second mixture. The second mixture is then mixed with dehydrating agent B and stirred at 1300 rpm for 20 minutes until homogeneous, forming the third mixture. The third mixture is then mixed with dehydrating agent A and stirred at 550 rpm for 10 minutes until homogeneous. The mixture is then filtered through a 300-mesh filter to obtain the various conformal coatings.

[0102] The formulations for Examples 1-10 can be found in Table 1 below.

[0103] Table 1

[0104]

[0105] The formulations for Comparative Examples 1-7 can be found in Table 2 below.

[0106] Table 2

[0107] raw material Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Reactive diluent 53.7 18.7 33.7 30.7 30.7 36.7 25.7 Initiator A 3 3 3 3 3 3 3 Initiator B 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Initiator C 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Dehydrating agent A 2 2 3 10 / 1 5 Dehydrating agent B 5 5 7 / 10 3 15 Resin A 35 70 / 55 55 55 50 Resin B / / / / / / / Resin C / / 52 / / / / Fluorescent whitening agent 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Additives 0.2 0.2 0.2 0.2 0.2 0.2 0.2 total 100 100 100 100 100 100 100

[0108] The performance of the above-mentioned conformal coatings was tested, and the spraying and coating film formation operations involved in the tests are shown below:

[0109] Dilute the conformal coating and butyl acetate to a suitable spraying viscosity in a certain ratio. Using a No. 2 cup (25℃), spray the coating onto the circuit board for 12 seconds with a 1.5mm nozzle. Bake at 60℃ for 6 minutes. Then, use a UV curing machine with a 360nm mercury lamp at 2500mJ / cm². 2 The paint film is cured by irradiation with energy and then placed in an environment with 60% humidity for 7 days to obtain a test paint film.

[0110] The various performance categories and performance standards to be tested for the coating film can be found in Table 3 below.

[0111] Table 3

[0112]

[0113] The performance test results of each conformal coating provided in Examples 1-10 can be found in Table 4 below.

[0114] Table 4

[0115]

[0116] The performance test results of each conformal coating provided in Comparative Examples 1-7 can be found in Table 5 below.

[0117] Table 5

[0118]

[0119] The performance test results of the conformal coatings provided in Examples 3, 7 and 6 were compared after being stored at 60°C for one month, as shown in Table 6 below.

[0120] Table 6

[0121]

[0122] It can be seen that the conformal coating prepared using the formulation of the conformal coating provided in the embodiments of the present invention can meet the test standards in terms of modulus, thermal shock, acid and alkali resistance, salt spray resistance, and damp heat resistance. Furthermore, after one month of storage, the viscosity of the conformal coating increases only slightly, for example, less than 3.5 times, and the loss of NCO groups is also relatively small, for example, less than 30%.

[0123] In embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0124] The above description is merely for the purpose of enabling those skilled in the art to understand the technical solutions of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-proof paint, characterized in that, The conformal coating comprises the following components by weight percentage: base resin 45%-65%, reactive diluent 25%-50%, initiator 2%-6%, dehydrating agent 7%-14%, and additives 0%-0.8%; The base resin contains NCO groups, and the dehydrating agent includes a chemical dehydrating agent and a physical dehydrating agent. The chemical dehydrating agent has a mass percentage of 2%-4% in the conformal coating, and the physical dehydrating agent has a mass percentage of 5%-10% in the conformal coating, and the mass ratio of the chemical dehydrating agent to the physical dehydrating agent is 1:2-3. The chemical dehydrating agent is p-methylbenzenesulfonyl isocyanate; The physical dehydrating agent is a molecular sieve dehydrating agent, and the static water absorption rate of the molecular sieve dehydrating agent is ≥20%. The matrix resin is a monofunctional polyurethane acrylate resin.

2. The conformal coating according to claim 1, characterized in that, The molecular sieve dehydrating agent is selected from at least one of 4A molecular sieve activation powder, 5A molecular sieve activation powder, and 13X molecular sieve activation powder.

3. The conformal coating according to claim 1, characterized in that, The active diluent is selected from at least one of isoborneol acrylate, isoborneol methacrylate, and hydroxyethyl methacrylate.

4. The conformal coating according to claim 1, characterized in that, The initiator includes at least one of α-hydroxyalkyl ketone photoinitiators and acyl oxide photoinitiators.

5. The conformal coating according to any one of claims 1-4, characterized in that, The additives include fluorescent whitening agents and leveling agents; The fluorescent whitening agent in the conformal coating has a mass percentage greater than 0 and less than or equal to 0.3%. The leveling agent has a mass percentage in the conformal coating that is greater than 0 and less than or equal to 0.5%.

6. A method for preparing a conformal coating, characterized in that, The conformal coating is as described in any one of claims 1-5, and the method for preparing the conformal coating includes: The reactive diluent, initiator, and optional additives are mixed evenly to form a first mixture; The first mixture, the matrix resin, and optional additives are mixed evenly to form a second mixture; The second mixture is mixed evenly with the physical dehydrating agent to form a third mixture; The third mixture is mixed evenly with a chemical dehydrating agent to obtain the conformal coating.

7. The application of the conformal coating according to any one of claims 1-5 on a circuit board.

Images