Silicone resin three-proof paint and preparation method thereof

Abstract

The present application relates to the field of protective paint technology, in particular to a silicone three-proof paint and a preparation method thereof, which is prepared by the following components in weight percentage: 30-40% phenyl silicone resin, 5-10% polydimethyl epoxy silane, 8-13% epoxy silane oligomer, 5-9% epoxy resin, 4-8% hydrogen silicone oil, 1-2% crosslinking agent, 0.5-1% catalyst and 3-6% tackifier, and the rest is environmentally friendly solvent. By adopting the above formula, the prepared silicone three-proof paint has good adhesion performance, fluidity and high temperature resistance, the high temperature resistance temperature can reach 200°C, and the curing speed is fast, easy to form a film, and has good transparency and weather resistance after curing.

Description

Technical Field

[0001] The present application relates to the technical field of protective paints, and in particular to a silicone resin three-proof paint and a preparation method thereof. Background Art

[0002] Conformal coating is a kind of coating used to protect circuit boards and related equipment from environmental corrosion, thereby improving and extending their service life and ensuring safety and reliability. At present, the common conformal coatings on the market mainly include polyurethane conformal coating, acrylic conformal coating and silicone conformal coating. Among them, silicone conformal coating has good weather resistance, high and low temperature resistance, excellent solvent resistance and high environmental protection. It is widely used in color TVs, refrigerators, washing machines, microwave ovens, air conditioners, telephones, electric water heaters and other ordinary household electronic products integrated circuits.

[0003] In order to improve the adhesion performance of silicone conformal coatings, silicone resins with large molecular weight are often selected. The reason is that the larger the molecular weight of the silicone resin, the better the adhesion mechanics. The larger the molecular weight means the higher the viscosity of the silicone resin. The higher the viscosity, the worse the fluidity, which is more difficult to apply. For this reason, a large amount of solvent is often selected to dilute the silicone resin to improve the fluidity of the conformal coating, which is beneficial to the construction of the conformal glue. However, the amount of solvent added generally exceeds 60% of the total amount, which will cause the adhesion performance and high temperature resistance of the conformal coating to decrease, affecting the use of the silicone conformal coating. Summary of the invention

[0004] In order to improve the problem that the adhesion and high temperature resistance of silicone conformal coatings decrease after being diluted with a large amount of solvents, the present application provides a silicone resin conformal coating and a preparation method thereof, so that the silicone conformal coating has good fluidity, adhesion and high temperature resistance.

[0005] In the first aspect, the present application provides a silicone conformal coating, which adopts the following technical solution:

[0006] A silicone conformal coating is prepared by including the following components in percentage by weight:

[0007] Phenyl silicone resin 30-40%

[0008] Polydimethyl epoxy silane 5-10%

[0009] Epoxy silane oligomer 8-13%

[0010] Epoxy resin 5-9%

[0011] Hydrogen silicone oil 4-8%

[0012] Crosslinking agent 1-2%

[0013] Catalyst 0.5-1%

[0014] Tackifier 3-6%

[0015] The rest is environmentally friendly solvent.

[0016] By adopting the above technical scheme, the prepared silicone resin three-proof paint has good adhesion performance, fluidity and high temperature resistance, the high temperature resistance can reach 200°C, and it has a fast curing speed and is easy to form a film. After curing, it has good transparency and weather resistance.

[0017] In this application, by using phenyl silicone resin, polydimethyl epoxy silane, epoxy silane oligomer and epoxy resin in a coordinated manner, the adhesion performance, weather resistance and high heat resistance of the three-proof paint are greatly improved. The reason is that the cross-linking density of phenyl silicone resin, polydimethyl epoxy silane, epoxy silane oligomer and epoxy resin after curing is high, and the network structure formed is stable and has strong adhesion, thereby improving the adhesion performance, transparency, weather resistance and high heat resistance of the three-proof paint. Polydimethyloxysilane has good wetting properties and epoxy silane oligomer has low surface activity. Adding polydimethyloxysilane and epoxy silane oligomer in this application can adjust the viscosity of the entire system, ensure that the silicone resin three-proof paint has good fluidity before curing, which is conducive to the use of the three-proof paint. After curing, it has good adhesion and high temperature resistance, and there is no need to add a large amount of solvent to adjust the fluidity of the three-proof paint. The amount of solvent added is less than 50%.

[0018] Among them, phenyl silicone resin contains phenyl, which greatly improves the high temperature resistance and weather resistance of the three-proof paint. However, the film-forming property is poor, and the required curing time is long and the temperature is high, which is not conducive to the coating of the three-proof paint. In this regard, the film-forming property of the three-proof paint is improved by adding epoxy resin in this application. Epoxy resin is a high molecular polymer with good film-forming property, which can improve the film-forming property of phenyl silicone. Polydimethylsiloxane can promote the compatibility of phenyl silicone resin and epoxy resin, increase the crosslinking density of phenyl silicone resin and epoxy resin, and then improve the adhesion performance of the three-proof paint. At the same time, polydimethylsiloxane also has good insulation and high temperature resistance. It is used to prepare three-proof paint, which can further improve the insulation and high temperature resistance of the three-proof paint.

[0019] After the phenyl silicone resin and the epoxy resin are cured, the surface of the cured layer formed is hard and not soft. The epoxy silane oligomer in the present application is used to improve the softness of the three-conformal paint after curing, which is beneficial to the use of the three-conformal paint.

[0020] Preferably, the catalyst is a platinum catalyst, wherein the platinum content is 3000ppm-5000ppm.

[0021] Preferably, the degree of polymerization of epoxysilane oligomer is 5-9, and its structure is

[0022]

[0023] By adopting the above-mentioned epoxy silane oligomer, the fluidity and high temperature resistance of the silicone resin conformal coating can be improved in one step.

[0024] Preferably, the phenyl silicone resin is prepared by mixing phenyl vinyl resin and polymethylphenyl silicone resin in a weight ratio of (6-15):5.

[0025] By adopting the above technical solution, phenyl vinyl resin and polymethylphenyl silicone resin are mixed in a specific ratio to further improve the adhesion and high temperature resistance of the three-proof adhesive. By using phenyl vinyl resin and polymethylphenyl silicone resin in a specific ratio, the silicone three-proof paint forms a strong adhesive cured layer when it is cured. The phenyl vinyl resin contains vinyl, which can increase the cross-linking points of the silicone three-proof paint, thereby increasing the cross-linking density, and further improving the adhesion and high temperature resistance of the silicone three-proof paint.

[0026] Preferably, the viscosity of the phenyl vinyl resin at 25°C is 2000-20000 mPa.s, the ethylene content (wt%) is 2.5-5.5%, and the degree of polymerization is 1000-1500; the viscosity of the polymethylphenyl silicone resin at 25°C is 400-600 cSt, and the degree of polymerization is 300-900.

[0027] By adopting the above technical solution, the parameters of phenyl vinyl resin and polymethylphenyl silicone resin are optimized, so that the three-proof paint has good adhesion and high temperature resistance while also having good fluidity and is easy to construct.

[0028] Preferably, the epoxy resin has a viscosity of 500-5000 Pa.s at 25° C. and an epoxy value of 35-100 eq / 100 g.

[0029] By adopting the above technical solution, the parameters of the epoxy resin are optimized, the adhesion performance and film-forming property of the three-proof paint are improved, the fluidity of the three-proof paint is adjusted, and the construction performance of the three-proof paint is improved.

[0030] Preferably, the environmentally friendly solvent includes at least one of ethyl acetate, cyclohexane, acetone, 1,4-butanediol, 1,3-propylene glycol, 1,4-cyclohexanol, neopentyl glycol, 1,6-hexanediol, and methyl propanediol.

[0031] By adopting the above technical solution, the fluidity of the three-proof paint is adjusted, and at the same time, the pollution of the solvent to the environment is reduced, which meets the environmental protection requirements.

[0032] Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.02-0.3 mol%, and the viscosity at 25° C. is 1000-5000 mPa.s.

[0033] By adopting the above technical scheme, the cross-linking of phenyl silicone resin, epoxy resin, epoxy silane oligomer and polydimethylsiloxane is promoted, which is conducive to forming a network structure with strong adhesion ability, thereby improving the adhesion performance of the three-proof paint.

[0034] Preferably, the viscosity of the polydimethyl epoxy silane is 1000-10000 dPa.s and the degree of polymerization is 100-300.

[0035] By adopting the above technical solution, the parameters of polydimethyl epoxy silane are optimized, so that the cross-linking of phenyl silicone resin, epoxy resin, epoxy silane oligomer and polydimethyl siloxane forms a silicone resin three-conformal paint cured layer with stronger adhesion, and at the same time, the fluidity of the silicone resin three-conformal paint is adjusted for easy use.

[0036] Preferably, the tackifier is prepared by mixing hydrogenated rosin, terpene resin and turpentine oil in a weight ratio of (10-15): (3-7): 30.

[0037] By adopting the above technical scheme, the adhesion performance of silicone three-proof paint is further improved. The tackifier is prepared by mixing hydrogenated rosin, terpene resin and turpentine in a specific proportion, and has good fluidity and tackifying effect. Terpene resin has high adhesion, heat resistance, oxidation resistance and weather resistance, and is used to prepare silicone three-proof paint, which can improve the adhesion performance, heat resistance, oxidation resistance and weather resistance of silicone three-proof paint. However, after curing, terpene resin will make the hardness of the cured layer of silicone three-proof paint harder and easy to crack. In contrast, the addition of hydrogenated rosin in this application increases the softness of the silicone three-proof paint after curing, and it is not easy to crack.

[0038] Preferably, the terpene resin has a purity of ≥99.9%, a viscosity of 600-1200 cps, and a softening point of 70-100°C.

[0039] By adopting the above technical solution, the parameters of terpene resin are optimized to further improve the adhesion and fluidity of silicone resin conformal coating.

[0040] In a second aspect, the present application provides a method for preparing a silicone conformal coating, using the following technical solution:

[0041] A method for preparing a silicone conformal coating comprises the following steps:

[0042] S1, stirring phenyl silicone resin, polydimethyl epoxy silane, epoxy silane oligomer and epoxy resin to obtain a mixture;

[0043] S2. Place the mixture in an environment with a vacuum degree of -0.09-0.1MPa and a temperature of 40-50°C, add hydrogenated silicone oil, a crosslinking agent, a catalyst, a tackifier and an environmentally friendly solvent while stirring, and obtain a silicone resin conformal coating.

[0044] By adopting the above technical scheme, the prepared silicone resin three-proof paint has good fluidity, strong adhesion performance, good aging resistance and good temperature resistance. In this application, the phenyl silicone resin with high viscosity, polydimethyl epoxy silane, epoxy silane oligomer and epoxy resin are first mixed evenly to form a stable system to prevent subsequent stratification. Under specific conditions, hydrogen-containing silicone oil, cross-linking agent, catalyst, tackifier and environmentally friendly solvent are added to ensure that the silicone resin three-proof paint does not bubble, which is conducive to subsequent curing and forms a smooth and flat film layer.

[0045] In summary, this application has the following beneficial effects:

[0046] 1. In the present application, a silicone conformal paint is prepared by mixing a specific proportion of phenyl silicone resin, polydimethyl epoxy silane, epoxy silane oligomer, epoxy resin, hydrogenated silicone oil, crosslinking agent, catalyst, tackifier and environmentally friendly solvent to improve the fluidity and adhesion performance of the silicone conformal paint. Among them, phenyl silicone resin, polydimethyl epoxy silane, epoxy silane oligomer and epoxy resin are cross-linked during curing to form a tight network structure with strong adhesion, thereby improving the adhesion performance and high temperature resistance of the silicone resin. Through the action of polydimethyl epoxy silane, epoxy silane oligomer and environmentally friendly solvent, the fluidity of the silicone resin conformal paint is adjusted without affecting the high temperature resistance and adhesion performance of the silicone resin conformal paint. DETAILED DESCRIPTION

[0047] Example

[0048] Example 1

[0049] A silicone resin conformal coating is prepared by the following method:

[0050] S1, 300 g of phenyl silicone resin, 50 g of polydimethyl epoxy silane, 80 g of epoxy silane oligomer and 50 g of epoxy resin were stirred to obtain a mixture;

[0051] S2. Place the mixture in an environment with a vacuum degree of -0.09 MPa and a temperature of 40°C, add 40 g of hydrogenated silicone oil, 10 g of a cross-linking agent (methyltrimethoxysilane), 5 g of a catalyst (platinum catalyst), 30 g of a tackifier and 435 g of an environmentally friendly solvent (ethyl acetate) while stirring, and obtain a silicone resin conformal coating.

[0052] The phenyl silicone resin is a phenyl vinyl resin having a viscosity of 2000 mPa.s at 25° C. and an ethylene content (wt %) of 2.5%.

[0053] The viscosity of polydimethyl epoxy silane is 1000 dPa.s and the degree of polymerization is 100.

[0054] The viscosity of epoxy resin at 25°C is 500mPa.s, and the epoxy value is 35eq / 100g.

[0055] The hydrogen content of hydrogen-containing silicone oil is 0.02 mol%, and the viscosity at 25°C is 1000 mPa.s.

[0056] The catalyst is a platinum catalyst, wherein the platinum content is 3000 ppm.

[0057] The tackifier is a terpene resin with a purity of 99.9%, a viscosity of 1200 cps and a softening point of 70°C.

[0058] The difference between Example 2-3 and Example 1 is that the types, amounts and experimental parameters of some raw materials for preparing the silicone resin conformal coating are different. The specific differences are shown in Table 1:

[0059] Table 1 Types, amounts and experimental parameters of raw materials used to prepare silicone conformal coatings in Examples 1-3

[0060]

[0061]

[0062] Example 4

[0063] A silicone conformal coating. The difference between this embodiment and embodiment 1 is that the phenyl silicone resin is a polymethylphenyl silicone resin, the viscosity of the methylphenyl silicone resin at 25° C. is 400 cSt, and the degree of polymerization is 300. The remaining experimental raw material types, amounts, and experimental parameters are consistent with those in embodiment 1.

[0064] Example 5

[0065] A silicone conformal paint. The difference between this embodiment and embodiment 1 is that the phenyl silicone resin is prepared by mixing 163.6 g of phenyl vinyl resin and 136.4 g of polymethylphenyl silicone resin in a weight ratio of 6:5, wherein the viscosity of the methylphenyl silicone resin at 25° C. is 400 cSt, and the degree of polymerization is 300. The remaining experimental raw material types, amounts, and experimental parameters are consistent with those in embodiment 1.

[0066] Example 6

[0067] A silicone conformal coating, the difference between this embodiment and embodiment 1 is that the phenyl silicone resin is prepared by mixing 225g of phenyl vinyl resin and 75g of polymethylphenyl silicone resin in a weight ratio of 15:5, wherein the viscosity of the methylphenyl silicone resin at 25°C is 400cSt and the degree of polymerization is 300, and the remaining experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 1.

[0068] Example 7

[0069] A silicone resin conformal paint. The difference between this embodiment and embodiment 5 is that the phenyl silicone resin is prepared by mixing 150g of phenyl vinyl resin and 150g of polymethylphenyl silicone resin in a weight ratio of 1:1, and the remaining experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 5.

[0070] Example 8

[0071] A silicone conformal coating. The difference between this embodiment and embodiment 5 is that the phenyl silicone resin is prepared by mixing 136.4 g of phenyl vinyl resin and 163.6 g of polymethylphenyl silicone resin in a weight ratio of 5:6, and the remaining experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 5.

[0072] Example 9

[0073] A silicone resin conformal coating. The difference between this embodiment and embodiment 5 is that the viscosity of the phenyl vinyl resin at 25° C. is 20000 mPa.s, the ethylene content (wt %) is 5.5%, and the remaining experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 5.

[0074] Example 10

[0075] A silicone conformal coating. The difference between this embodiment and embodiment 5 is that the phenyl silicone resin is a polymethylphenyl silicone resin, the viscosity of the methylphenyl silicone resin at 25° C. is 600 cSt, and the degree of polymerization is 900. The remaining experimental raw material types, amounts, and experimental parameters are consistent with those in embodiment 5.

[0076] Embodiment 11

[0077] A silicone conformal coating, the difference between this embodiment and embodiment 1 is that: the tackifier is prepared by mixing hydrogenated rosin, terpene resin and turpentine in a weight ratio of 10:3:30, and the other experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 1.

[0078] Example 12

[0079] A silicone conformal coating. The difference between this embodiment and embodiment 5 is that the tackifier is prepared by mixing hydrogenated rosin, terpene resin and turpentine in a weight ratio of 15:7:30, and the remaining experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 5.

[0080] Embodiment 13

[0081] A silicone resin conformal coating. The difference between this embodiment and embodiment 1 is that the viscosity of the epoxy resin at 25° C. is 6000 mPa.s, the epoxy value is 35 eq / 100 g, and the other experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 1.

[0082] Embodiment 14

[0083] A silicone conformal coating. The difference between this embodiment and embodiment 1 is that the viscosity of polydimethyl epoxy silane is 11000 dPa.s, the degree of polymerization is 100, and the other experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 1.

[0084] Embodiment 15

[0085] A silicone conformal coating. The difference between this embodiment and embodiment 1 is that the viscosity of polydimethyl epoxy silane is 9000 dPa.s, the degree of polymerization is 100, and the other experimental raw material types, amounts and experimental parameters are consistent with those in embodiment 1.

[0086] Comparative Example

[0087] Comparative Example 1

[0088] A silicone resin conformal coating. The difference between this comparative example and Example 1 is that methyl silicone resin is used instead of phenyl silicone resin, and the other experimental raw material types, amounts and experimental parameters are consistent with those in Example 1.

[0089] The viscosity of the methyl silicone resin at 25°C is 2000 mPa.s and the molecular weight is 4000.

[0090] Comparative Example 2

[0091] A silicone resin conformal coating. The difference between this comparative example and Example 1 is that polyether polyol is used instead of polydimethyl epoxy silane, and the other experimental raw material types, amounts and experimental parameters are consistent with those in Example 1.

[0092] The molecular weight of the polyether polyol is 3000, and the viscosity at 25°C is 2000 mPa.s.

[0093] Comparative Example 3

[0094] A silicone resin conformal coating. The difference between this comparative example and Example 1 is that stearic acid is used instead of epoxy silane oligomer, and the other experimental raw material types, amounts and experimental parameters are consistent with those in Example 1.

[0095] Comparative Example 4

[0096] A silicone resin conformal coating. The difference between this comparative example and Example 1 is that polyurethane resin is used instead of epoxy resin, and the other experimental raw material types, amounts and experimental parameters are consistent with those in Example 1.

[0097] The viscosity of the polyurethane resin at 25° C. is 500 mPa.s, and the weight average molecular weight of the polyurethane resin is 2,000.

[0098] Performance testing

[0099] The silicone resin conformal coatings prepared in Examples 1-15 and the silicone resin conformal coatings prepared in Comparative Examples 1-4 were subjected to viscosity tests, adhesion tests, constant temperature and humidity weathering tests, thermal shock weathering tests, and salt spray resistance tests.

[0100] Detection method / test method

[0101] Viscosity test: Test conditions: 25±3℃, 45-55% humidity, measured using a rotational viscometer;

[0102] Adhesion test: refer to GB / T9286-1998;

[0103] Constant temperature and humidity weathering test: The paint film is cured on the titanium electrode plate, the dry film thickness is controlled to be 60μm, and placed in a constant temperature and humidity chamber at 200℃ and 85%RH for 720h;

[0104] Thermal shock weathering test: The paint film is cured on the titanium electrode plate, the dry film thickness is controlled to be 60μm, and placed in an environmental test box with a high temperature of 200℃ and a low temperature of -40℃, the high and low temperature holding time is 30 minutes each, and the high and low temperature conversion time is 2 minutes, and 1000 cycles are performed;

[0105] Salt spray resistance test: The paint film is cured on the titanium electrode plate, the dry film thickness is controlled to 60μm, and a neutral salt spray test is performed. The test method refers to GB / T 2423.17-2008.

[0106] In the constant temperature and humidity weathering test, thermal shock weathering test and salt spray resistance test, observe whether the paint film has white spots, bubbles, pinholes, cracks, fine cracks, wrinkles, shedding, separation, discoloration and other surface phenomena. The experimental data are shown in Table 2:

[0107] Table 2 Experimental data of Examples 1-15 and Comparative Examples 1-4

[0108]

[0109] It can be seen from Examples 1-15, Comparative Examples 1-4 and Table 2 that the silicone resin triple-proof adhesive prepared in the present application has good adhesion performance, fluidity, temperature resistance and aging resistance.

[0110] Compared with Example 1 and Comparative Example 1, the viscosity in Comparative Example 1 is greater than that in Example 1, the adhesion performance is less than that in Example 1, and blistering occurs in the thermal shock weathering test, and pinholes occur in the salt spray resistance test, indicating that the use of phenyl silicone resin in this application can further improve the comprehensive performance of the three-proof paint, such as flow performance, adhesion performance and temperature resistance.

[0111] Compared with Example 1 and Comparative Example 2, the viscosity in Comparative Example 2 is greater than that in Example 1, the adhesion performance is less than that in Example 1, and blistering occurs in the thermal shock weathering test, and discoloration occurs in the salt spray resistance test, indicating that the preparation of the conformal coating by adding polydimethoxysilane is beneficial to improving the comprehensive performance of the conformal coating, such as fluidity, adhesion performance and temperature resistance.

[0112] Compared with Example 1 and Comparative Example 3, the viscosity in Comparative Example 3 is greater than that in Example 1, the adhesion performance is less than that of Example 1, and shedding phenomenon occurs in the constant temperature and humidity weathering test, blistering phenomenon occurs in the thermal shock weathering test, and blistering phenomenon occurs in the salt spray resistance test, indicating that the epoxy silane oligomer improves the fluidity, adhesion performance, temperature resistance and weather resistance of the three-proof paint.

[0113] Compared with Example 1 and Comparative Example 4, the viscosity in Comparative Example 4 is greater than that in Example 1, the adhesion performance is less than that in Example 1, and shedding phenomenon occurs in the constant temperature and humidity weathering test, pinhole phenomenon occurs in the thermal shock weathering test, and discoloration phenomenon occurs in the salt spray resistance test. This shows that the use of epoxy resin to prepare the three-proof paint in this application can further improve the comprehensive performance of the three-proof paint, such as flow performance, adhesion performance and temperature resistance.

[0114] Compared with Example 1 and Examples 4-10, Examples 5-6 and 9-10 have the lowest viscosity, the highest fluidity, and the best adhesion performance; followed by Examples 7-8, which indicates that the use of phenyl vinyl resin and polymethylphenyl silicone resin in a specific proportion has a positive effect on improving the fluidity and adhesion performance of the three-proof adhesive.

[0115] Compared with Example 1 and Example 11, and compared with Example 5 and Example 12, the fluidity in Example 11 is lower than that in Example 1, and the adhesion performance is higher than that in Example 1, indicating that the fluidity and adhesion performance of the three-proof adhesive can be further improved by applying the preparation of the tackifier.

[0116] Compared with Example 1 and Examples 14-15, Example 14 has a large viscosity, and Example 15 exhibits bubbling in the thermal shock weathering test, indicating that optimizing the parameters of polydimethylsiloxane is beneficial to improving the fluidity, adhesion, temperature resistance, and weather resistance of the conformal coating.

[0117] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A silicone conformal coating, characterized in that: The preparation comprises the following components in weight percentage: Phenyl silicone resin 30-40% Polydimethyl epoxy silane 5-10% Epoxy silane oligomer 8-13% Epoxy resin 5-9% Hydrogen silicone oil 4-8% Crosslinking agent 1-2% Catalyst 0.5-1% Thickener 3-6% The remaining amount is environmentally friendly solvent; The phenyl silicone resin is prepared by mixing phenyl vinyl resin and polymethylphenyl silicone resin in a weight ratio of (6-15):5; The viscosity of the phenyl vinyl resin at 25°C is 2000-20000 mPa.s, the ethylene content wt% is 2.5-5.5%, and the degree of polymerization is 1000-1500; the viscosity of the polymethylphenyl silicone resin at 25°C is 400-600 cSt, and the degree of polymerization is 300-900; The epoxy resin has a viscosity of 500-5000 mPa.s at 25°C and an epoxy value of 35-100 eq / 100g; The environmentally friendly solvent includes at least one of ethyl acetate, cyclohexane, acetone, 1,4-butanediol, 1,3-propylene glycol, 1,4-cyclohexanol, neopentyl glycol, 1,6-hexanediol, and methyl propanediol; The hydrogen content of the hydrogen-containing silicone oil is 0.02-0.3 mol%, and the viscosity at 25° C. is 1000-5000 mPa.s; The viscosity of the polydimethyl epoxy silane at 25° C. is 1000-10000 dPa.s, and the degree of polymerization is 100-300; The tackifier is prepared by mixing hydrogenated rosin, terpene resin and turpentine oil in a weight ratio of (10-15): (3-7): 30; The terpene resin has a purity of ≥99.9%, a viscosity of 600-1200 cps, and a softening point of 70-100°C; The preparation method of the silicone resin conformal coating comprises the following preparation steps: S1, stirring phenyl silicone resin, polydimethyl epoxy silane, epoxy silane oligomer and epoxy resin to obtain a mixture; S2. Place the mixture in an environment with a vacuum degree of -0.09-0.1MPa and a temperature of 40-50°C, add hydrogenated silicone oil, a crosslinking agent, a catalyst, a tackifier and an environmentally friendly solvent while stirring, and obtain a silicone resin conformal coating.

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