A coating for the local spraying of carbon fiber composites

Abstract

The present application relates to a kind of coating for the local spraying of carbon fiber composite material, including by weight parts: 56-78 epoxy modified acrylic resin, 11-22 modified fillers, 0.2-0.6 dispersing agent, 0.1-0.5 antifoam agent, 0.1-0.5 leveling agent, 18-26 curing agent and 40-60 solvents.The coating prepared by the present application can be used for the surface of carbon fiber workpiece Local coating, thereby repairing the problem of workpiece surface, will not produce surface unevenness and cover badly etc. Problem in the process of use, it is favorable to improve the overall process efficiency of coating.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber, and more specifically to a coating for localized spraying of carbon fiber composite materials. Background Technology

[0002] With the development of the low-altitude economy, carbon fiber composite pipes, with their lightweight, high strength, high temperature resistance, wear resistance, and corrosion resistance, are increasingly favored by various industries such as aerospace, military, wind power, automotive, medical, and sports. Since carbon fiber composite parts are used in structural components, they require higher wear resistance, impermeability, and corrosion resistance, placing higher demands on the surface properties of carbon fiber materials. Therefore, how to strengthen the surface of carbon fiber composites has become a key research focus for carbon fiber applications. Common surface treatment methods for carbon fiber include surface cleaning, vapor phase oxidation, surface coating, plasma treatment, and liquid phase oxidation. Painting the carbon fiber surface is one of the surface coating methods. Surface roughening and overall grinding are the main pretreatments for painting, followed by paint curing. To address problems encountered in painting large or complex carbon fiber workpieces, such as uneven surfaces, flow marks, exposed substrate, poor coverage, and orange peel, the common approach is to perform overall grinding and repainting to ensure uniform coating. However, spraying after overall grinding not only wastes manpower and time, but may also cause over-grinding of the workpiece, resulting in a reduction in workpiece performance. At the same time, the coated surface often has poor adhesion and paint peeling after a long time. Summary of the Invention

[0003] In view of the problems existing in the prior art, the purpose of the present invention is to provide a coating for local spraying of carbon fiber composite materials.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] In a first aspect, the present invention provides a coating for localized spraying of carbon fiber composite materials, comprising, by weight parts:

[0006] 56-78 parts epoxy-modified acrylic resin, 11-22 parts modified filler, 0.2-0.6 parts dispersant, 0.1-0.5 parts defoamer, 0.1-0.5 parts leveling agent, 18-26 parts curing agent, and 40-60 parts solvent.

[0007] Preferably, the preparation method of the epoxy-modified acrylic resin includes:

[0008] Epoxy resin E-20 and ethylene glycol butyl ether are mixed and heated to 80-100℃ under nitrogen protection. After stirring until completely dissolved, a mixture of acrylic acid and half of the initiator is added dropwise, with the addition time controlled at 2-3 hours. After the addition is complete, the remaining half of the initiator is added dropwise, and the temperature is raised to 110-120℃. The mixture is kept at this temperature and stirred for 2-3 hours. After cooling to room temperature, epoxy-modified acrylic resin is obtained.

[0009] Preferably, in the preparation process of the epoxy-modified acrylic resin, the mass-volume ratio of epoxy resin E-20, acrylic acid and ethylene glycol butyl ether is (1-3)g:(24-48)g:(40-60)mL.

[0010] Preferably, in the preparation process of the epoxy-modified acrylic resin, the total amount of initiator used is 1%-5% of the total mass of acrylic acid, and the initiator is one of benzoic acid peroxide, cumene hydroperoxide, and tert-butyl methyl peroxide.

[0011] Preferably, the dispersant is one of TEGO-670, TEGO-760W, and TEGO-755W.

[0012] Preferably, the defoamer is one of BYK-A525, BYK-A530, BYK-088, or BYK-1615.

[0013] Preferably, the leveling agent is an organosilicon leveling agent, and the model is one of HY-3510, HY-8110, HY-5057, and HY-1484.

[0014] Preferably, the curing agent is an HDI trimer curing agent, with the brand name Wanhua HT-100, Wanhua HT-600, and Tosoh HRX-90B.

[0015] Preferably, the solvent is one of ethyl acetate, butyl acetate, toluene, and xylene.

[0016] Preferably, the modified filler is prepared by:

[0017] S1. Mix calcium boride micro powder and sodium hydroxide solution, stir in a water bath at 60-80℃ for 3-5 hours, then filter out the solid product and dry it to obtain activated calcium boride; then disperse the activated calcium boride in ethanol, add γ-glycidyl etheroxypropyltrimethoxysilane (KH-560), reflux at 50-60℃ for 6-10 hours, filter out the solid product and dry it to obtain epoxy-modified calcium boride;

[0018] S2. Tetrahydrofuran acrylate (THFA) and 4,6-diamino-2-mercaptopyrimidine (C4H6N4S) were added sequentially to N,N-dimethylformamide (DMF). After stirring thoroughly until homogeneous, a photoinitiator was added, and the mixture was stirred under ultraviolet light for 1-2 hours. After the treatment was completed, the solvent was removed, and the mixture was dried to obtain the sulfide compound.

[0019] S3. Mix the epoxy-oxidized calcium boride and the sulfide compound into anhydrous ethanol, add a few drops of triethylamine, heat to 70-80℃, reflux for 4-6 hours, remove the solvent after treatment, and dry to obtain the modified filler.

[0020] Preferably, in S1, the calcium boride micro powder has the molecular formula CaB6, a purity higher than 99%, and a particle size of 10-20 μm.

[0021] Preferably, in S1, the mass fraction of sodium hydroxide solution is 10%-20%, and the mass-volume ratio of calcium boride micro powder to sodium hydroxide solution is 1g:(15-25)mL.

[0022] Preferably, in S1, the mass-to-volume ratio of active calcium boride, γ-glycidyl etheroxypropyltrimethoxysilane, and ethanol is 1 g:(0.15-0.35) g:(15-25) mL.

[0023] Preferably, in S2, the mass-to-volume ratio of tetrahydrofuran acrylate, 4,6-diamino-2-mercaptopyrimidine, and N,N-dimethylformamide is (0.26-0.52) g:(0.22-0.44) g:(10-20) mL.

[0024] Preferably, in step S2, the photoinitiator is photoinitiator BDK, and the amount added is 2%-8% of the mass of 4,6-diamino-2-mercaptopyrimidine; the ultraviolet conditions are: ultraviolet lamp power 100-200W, irradiation distance 10-20cm.

[0025] Preferably, in S3, the mass-to-volume ratio of epoxy borate calcium, thioether compound, triethylamine and anhydrous ethanol is 1g:(0.37-0.59)g:(0.003-0.008)g:(20-30)mL.

[0026] Secondly, the present invention provides a method for preparing a coating for localized spraying of carbon fiber composite materials, comprising:

[0027] Step 1: First, mix the epoxy-modified acrylic resin, modified filler, dispersant, and solvent, and stir thoroughly until homogeneous;

[0028] Step 2: Add defoamer and leveling agent to the mixture from Step 1, and stir again until well mixed.

[0029] Step 3: Add curing agent to the mixture from Step 2, stir well, and you will get a coating that can be applied.

[0030] Thirdly, the present invention provides an application of a coating for local spraying of carbon fiber composite materials. After the coating is sprayed onto a local area of ​​the carbon fiber composite material, it is baked at 70±5℃ for 30-60 minutes.

[0031] The beneficial effects of this invention are as follows:

[0032] 1. The coating prepared by this invention can be used for local coating of carbon fiber workpieces to repair surface problems. During use, it will not cause problems such as uneven surface or poor coverage in the adjustment area, which is conducive to improving the overall process efficiency of coating.

[0033] 2. The coating prepared by this invention can be used for localized sanding and painting of carbon fiber workpieces. The sprayed paint film will not have flow marks, exposed substrate, poor coverage, orange peel, etc. It not only has good adhesion, but also high strength and durability, and can be used for a long time without peeling off.

[0034] 3. The coating of the present invention uses epoxy-modified acrylic resin prepared from epoxy resin E-20 and acrylic acid as the main material, and the filler uses modified filler prepared from epoxy-oxidized calcium boride and sulfide compounds. When the coating is applied to the carbon fiber surface, it has the advantages of high strength, strong adhesion and good weather resistance.

[0035] 4. In the preparation of modified fillers, epoxy-oxidized calcium boride is first activated with an alkaline solution, and then grafted with epoxy silane to obtain epoxy-oxidized calcium boride; while the sulfide compound is obtained by combining tetrahydrofuran acrylate containing unsaturated double bonds and 4,6-diamino-2-mercaptopyrimidine containing thiol groups through a click chemistry reaction to obtain an amino-containing sulfide compound; then, through the epoxy-amino binding reaction, the sulfide compound is crosslinked and fixed on the surface of calcium boride to finally obtain a core-shell coated modified filler.

[0036] 5. Because the surface coating of the modified filler contains not only sulfide groups, but also tetrahydrofuran ester groups and pyrimidine groups, it not only makes the modified filler more compatible with the resin, but also has a significant impact on improving the performance of the coating. Detailed Implementation

[0037] The technical solution of the present invention is illustrated below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or defining the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0038] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0039] The present invention will be further described below with reference to the following embodiments.

[0040] Example 1

[0041] A coating for localized spraying of carbon fiber composite materials, comprising, by weight parts:

[0042] 67 parts epoxy-modified acrylic resin, 16 parts modified filler, 0.4 parts dispersant, 0.3 parts defoamer, 0.2 parts leveling agent, 22 parts curing agent and 50 parts solvent.

[0043] The preparation methods for epoxy-modified acrylic resin include:

[0044] Epoxy resin E-20 and ethylene glycol butyl ether were mixed and heated to 90°C under nitrogen protection. After stirring until completely dissolved, a mixture of acrylic acid and 1.5% (by weight) benzoic acid peroxide was added dropwise over a period of 2.5 hours. After the addition was complete, the remaining 1.5% (by weight) benzoic acid peroxide was added dropwise. The mass-to-volume ratio of epoxy resin E-20, acrylic acid, and ethylene glycol butyl ether was 2 g:36 g:50 mL. The mixture was heated to 115°C and stirred for 2.5 hours. After cooling to room temperature, epoxy-modified acrylic resin was obtained.

[0045] The dispersant is TEGO-670; the defoamer is BYK-A525; the leveling agent is silicone leveling agent HY-3510; the curing agent is Wanhua HT-100HDI trimer curing agent; and the solvent is butyl acetate.

[0046] The preparation method of the modified filler is as follows:

[0047] S1. Calcium boride micro powder (CaB6, purity higher than 99%, particle size 10-20μm) and 15wt% sodium hydroxide solution were mixed, with a mass-to-volume ratio of 1g:20mL. The mixture was stirred in a 70℃ water bath for 4 hours, and then the solid product was filtered out and dried to obtain activated calcium boride. Then, the activated calcium boride was dispersed in ethanol, and γ-glycidoxypropyltrimethoxysilane (KH-560) was added, with a mass-to-volume ratio of 1g:0.25g:20mL for activated calcium boride. The mixture was refluxed at 55℃ for 8 hours, and the solid product was filtered out and dried to obtain epoxy-modified calcium boride.

[0048] S2. Tetrahydrofuran acrylate (THFA) and 4,6-diamino-2-mercaptopyrimidine (C4H6N4S) were sequentially added to N,N-dimethylformamide (DMF). The mass-to-volume ratio of tetrahydrofuran acrylate, 4,6-diamino-2-mercaptopyrimidine, and N,N-dimethylformamide was 0.39 g:0.33 g:15 mL. After stirring thoroughly until homogeneous, photoinitiator BDK was added at 5% of the mass of 4,6-diamino-2-mercaptopyrimidine. The mixture was stirred under UV conditions for 1.5 h with a UV lamp power of 150 W and an irradiation distance of 15 cm. After the treatment was completed, the solvent was removed, and the mixture was dried to obtain a sulfide compound.

[0049] S3. Epoxylated calcium boride and sulfide compound were mixed into anhydrous ethanol, and a few drops of triethylamine were added. The mass-volume ratio of epoxylated calcium boride, sulfide compound, triethylamine and anhydrous ethanol was 1 g: 0.48 g: 0.005 g: 25 mL. The mixture was heated to 75 °C and refluxed for 5 h. After the treatment, the solvent was removed and the mixture was dried to obtain the modified filler.

[0050] The preparation method of the coating for localized spraying of carbon fiber composite materials as described above includes:

[0051] Step 1: First, mix the epoxy-modified acrylic resin, modified filler, dispersant, and solvent, and stir thoroughly until homogeneous;

[0052] Step 2: Add defoamer and leveling agent to the mixture from Step 1, and stir again until well mixed.

[0053] Step 3: Add curing agent to the mixture from Step 2, stir well, and you will get a coating that can be applied.

[0054] Example 2

[0055] A coating for localized spraying of carbon fiber composite materials, comprising, by weight parts:

[0056] 56 parts epoxy-modified acrylic resin, 11 parts modified filler, 0.2 parts dispersant, 0.1 parts defoamer, 0.1 parts leveling agent, 18 parts curing agent and 40 parts solvent.

[0057] The preparation methods for epoxy-modified acrylic resin include:

[0058] Epoxy resin E-20 and ethylene glycol butyl ether were mixed and heated to 80°C under nitrogen protection. After stirring until completely dissolved, a mixture of acrylic acid and half of the initiator was added dropwise over a period of 2 hours. After the addition was complete, the remaining half of the initiator was added. The temperature was raised to 110°C and stirred for 2 hours. After cooling to room temperature, epoxy-modified acrylic resin was obtained. The mass-volume ratio of epoxy resin E-20, acrylic acid, and ethylene glycol butyl ether was 1 g:24 g:40 mL. The total amount of initiator used was 1% of the total mass of acrylic acid, and the initiator was cumene hydroperoxide.

[0059] The dispersant is TEGO-760W; the defoamer is BYK-A530; the leveling agent is silicone leveling agent, model HY-8110; the curing agent is HDI trimer curing agent, brand Wanhua HT-600; and the solvent is ethyl acetate.

[0060] The preparation method of the modified filler is as follows:

[0061] S1. Calcium boride micro powder (CaB6, purity higher than 99%, particle size 10-20μm) and 10wt% sodium hydroxide solution are mixed, with a mass-to-volume ratio of 1g:15mL. The mixture is stirred in a water bath at 60℃ for 3h, then the solid product is filtered out and dried to obtain activated calcium boride. Then, the activated calcium boride is dispersed in ethanol, and γ-glycidoxypropyltrimethoxysilane (KH-560) is added, with a mass-to-volume ratio of 1g:0.15g:15mL. The mixture is refluxed at 50℃ for 6h, the solid product is filtered out, and dried to obtain epoxy-oxidized calcium boride.

[0062] S2. Tetrahydrofuran acrylate (THFA) and 4,6-diamino-2-mercaptopyrimidine (C4H6N4S) were sequentially added to N,N-dimethylformamide (DMF). The mass-to-volume ratio of tetrahydrofuran acrylate, 4,6-diamino-2-mercaptopyrimidine, and N,N-dimethylformamide was 0.26 g:0.22 g:10 mL. After stirring thoroughly until homogeneous, photoinitiator BDK was added at 2% of the mass of 4,6-diamino-2-mercaptopyrimidine. The mixture was stirred under UV conditions for 1 h with a UV lamp power of 100 W and an irradiation distance of 10 cm. After the treatment was completed, the solvent was removed, and the mixture was dried to obtain a sulfide compound.

[0063] S3. Epoxylated calcium boride and sulfide compound were mixed into anhydrous ethanol, and a few drops of triethylamine were added. The mass-volume ratio of epoxylated calcium boride, sulfide compound, triethylamine and anhydrous ethanol was 1 g: 0.37 g: 0.003 g: 20 mL. The mixture was heated to 70 °C and refluxed for 4 h. After the treatment, the solvent was removed and the mixture was dried to obtain the modified filler.

[0064] The preparation method of the coating for localized spraying of carbon fiber composite materials as described above includes:

[0065] Step 1: First, mix the epoxy-modified acrylic resin, modified filler, dispersant, and solvent, and stir thoroughly until homogeneous;

[0066] Step 2: Add defoamer and leveling agent to the mixture from Step 1, and stir again until well mixed.

[0067] Step 3: Add curing agent to the mixture from Step 2, stir well, and you will get a coating that can be applied.

[0068] Example 3

[0069] A coating for localized spraying of carbon fiber composite materials, comprising, by weight parts:

[0070] 78 parts epoxy-modified acrylic resin, 22 parts modified filler, 0.6 parts dispersant, 0.5 parts defoamer, 0.5 parts leveling agent, 26 parts curing agent and 60 parts solvent.

[0071] The preparation methods for epoxy-modified acrylic resin include:

[0072] Epoxy resin E-20 and ethylene glycol butyl ether were mixed and heated to 100°C under nitrogen protection. After stirring until completely dissolved, a mixture of acrylic acid and half of the initiator was added dropwise over a period of 2-3 hours. After the addition was complete, the remaining half of the initiator was added. The temperature was raised to 120°C and stirred for 3 hours. After cooling to room temperature, epoxy-modified acrylic resin was obtained. The mass-volume ratio of epoxy resin E-20, acrylic acid, and ethylene glycol butyl ether was 3g:48g:60mL. The total amount of initiator used was 5% of the total mass of acrylic acid, and the initiator was tert-butyl benzoate peroxide.

[0073] The dispersant is TEGO-755W; the defoamer is BYK-1615; the leveling agent is silicone leveling agent, model HY-1484; the curing agent is HDI trimer curing agent, brand Tosoh HRX-90B; and the solvent is xylene.

[0074] The preparation method of the modified filler is as follows:

[0075] S1. Calcium boride micro powder (CaB6, purity higher than 99%, particle size 10-20μm) and 20wt% sodium hydroxide solution are mixed, with a mass-to-volume ratio of 1g:25mL. The mixture is stirred in an 80℃ water bath for 5h, then the solid product is filtered out and dried to obtain activated calcium boride. Then, the activated calcium boride is dispersed in ethanol, and γ-glycidoxypropyltrimethoxysilane (KH-560) is added, with a mass-to-volume ratio of 1g:(0.15-0.35)g:(15-25)mL. The mixture is refluxed at 50-60℃ for 6-10h, the solid product is filtered out, and dried to obtain epoxy-modified calcium boride.

[0076] S2. Tetrahydrofuran acrylate (THFA) and 4,6-diamino-2-mercaptopyrimidine (C4H6N4S) were sequentially added to N,N-dimethylformamide (DMF). The mass-to-volume ratio of tetrahydrofuran acrylate, 4,6-diamino-2-mercaptopyrimidine, and N,N-dimethylformamide was (0.26-0.52) g:(0.22-0.44) g:(10-20) mL. After stirring thoroughly until homogeneous, photoinitiator BDK was added. The amount added was 2%-8% of the mass of 4,6-diamino-2-mercaptopyrimidine. The mixture was stirred under ultraviolet light for 1-2 hours. The ultraviolet lamp power was 100-200 W and the irradiation distance was 10-20 cm. After the treatment was completed, the solvent was removed and the mixture was dried to obtain the sulfide compound.

[0077] S3. Mix the epoxy-oxidized calcium boride and the sulfide compound into anhydrous ethanol, and add a few drops of triethylamine. The mass-volume ratio of epoxy-oxidized calcium boride, sulfide compound, triethylamine and anhydrous ethanol is 1g:(0.37-0.59)g:(0.003-0.008)g:(20-30)mL. Heat to 70-80℃ and reflux for 4-6 hours. After treatment, remove the solvent and dry to obtain the modified filler.

[0078] The preparation method of the coating for localized spraying of carbon fiber composite materials as described above includes:

[0079] Step 1: First, mix the epoxy-modified acrylic resin, modified filler, dispersant, and solvent, and stir thoroughly until homogeneous;

[0080] Step 2: Add defoamer and leveling agent to the mixture from Step 1, and stir again until well mixed.

[0081] Step 3: Add curing agent to the mixture from Step 2, stir well, and you will get a coating that can be applied.

[0082] Comparative Example 1

[0083] A coating for local spraying of carbon fiber composite materials differs from Example 1 in that the modified filler is replaced with calcium boride micro powder.

[0084] Comparative Example 2

[0085] A coating for localized spraying of carbon fiber composite materials differs from Example 1 in that the modified filler is replaced with a mixture of calcium boride micro powder and tetrahydrofuran acrylate, with a mass ratio of calcium boride micro powder to tetrahydrofuran acrylate of 1:0.37.

[0086] Comparative Example 3

[0087] A coating for localized spraying of carbon fiber composite materials differs from Example 1 in that the modified filler is replaced with a mixture of calcium boride micro powder and 4,6-diamino-2-mercaptopyrimidine, with a mass ratio of calcium boride micro powder to 4,6-diamino-2-mercaptopyrimidine of 1:0.37.

[0088] Experimental Example

[0089] The coatings prepared in Examples 1-3 were applied as follows: the surface of the carbon fiber board (Shenzhen Albis Technology Co., Ltd.) was sanded with #1000-2000 sandpaper, wiped with blown dust, and a 100μm thick coating was sprayed on. Then, it was baked at 70±5℃ for 45 minutes. The performance of the sprayed coating was tested. The surface condition was observed visually based on the dried paint film. The impact resistance test was conducted according to GB / T 1732-1993, the adhesion test according to GB / T 9286-1998, the hardness test according to GB / T6739-2006, and the weather resistance test according to the QUV-A method of GB / T 1865-1997. The gloss loss rate and color difference (ΔE) after 1000h treatment were tested.

[0090] The test results are shown in the table below:

[0091] Table 1 Performance test results of different coatings

[0092]

[0093] As can be seen from Table 1 above, when the coating prepared in Example 1 is used in carbon fiber composite material, it has a good surface morphology, no orange peel, no exposed substrate, and high adhesion and hardness, good impact resistance, and excellent weather resistance.

[0094] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0095] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A coating for localized spraying of carbon fiber composite materials, characterized in that, Calculated by weight, including: 56-78 parts epoxy-modified acrylic resin, 11-22 parts modified filler, 0.2-0.6 parts dispersant, 0.1-0.5 parts defoamer, 0.1-0.5 parts leveling agent, 18-26 parts curing agent, and 40-60 parts solvent; The modified filler is prepared by: S1. Mix calcium boride micro powder and sodium hydroxide solution, stir in a water bath at 60-80℃ for 3-5 hours, then filter out the solid product and dry it to obtain activated calcium boride; then disperse the activated calcium boride in ethanol, add γ-glycidyl etheroxypropyltrimethoxysilane, reflux at 50-60℃ for 6-10 hours, filter out the solid product and dry it to obtain epoxy-modified calcium boride. S2. Tetrahydrofuran acrylate and 4,6-diamino-2-mercaptopyrimidine were added sequentially to N,N-dimethylformamide and stirred thoroughly until homogeneous. Then, a photoinitiator was added and stirred under UV conditions for 1-2 hours. After the treatment was completed, the solvent was removed and the mixture was dried to obtain the sulfide compound. S3. Mix the epoxy-oxidized calcium boride and the sulfide compound into anhydrous ethanol, add a few drops of triethylamine, heat to 70-80℃, reflux for 4-6 hours, remove the solvent after treatment, and dry to obtain the modified filler.

2. The coating for localized spraying of carbon fiber composite materials according to claim 1, characterized in that, The preparation method of the epoxy-modified acrylic resin includes: Epoxy resin E-20 and ethylene glycol butyl ether are mixed and heated to 80-100℃ under nitrogen protection. After stirring until completely dissolved, a mixture of acrylic acid and half of the initiator is added dropwise, with the addition time controlled at 2-3 hours. After the addition is complete, the remaining half of the initiator is added dropwise, and the temperature is raised to 110-120℃. The mixture is kept at this temperature and stirred for 2-3 hours. After cooling to room temperature, epoxy-modified acrylic resin is obtained.

3. The coating for localized spraying of carbon fiber composite materials according to claim 2, characterized in that, In the preparation process of the epoxy-modified acrylic resin, the mass-volume ratio of epoxy resin E-20, acrylic acid and ethylene glycol butyl ether is (1-3)g:(24-48)g:(40-60)mL.

4. The coating for localized spraying of carbon fiber composite materials according to claim 2, characterized in that, In the preparation process of the epoxy-modified acrylic resin, the total amount of initiator used is 1%-5% of the total mass of acrylic acid, and the initiator is one of benzoic acid peroxide, cumene hydroperoxide, and tert-butyl methyl peroxide.

5. The coating for localized spraying of carbon fiber composite materials according to claim 1, characterized in that, The dispersant is one of TEGO-670, TEGO-760W, and TEGO-755W; the defoamer is one of BYK-A525, BYK-A530, BYK-088, and BYK-1615; and the leveling agent is an organosilicon leveling agent, model HY-3510, HY-8110, HY-5057, and HY-1484.

6. The coating for localized spraying of carbon fiber composite materials according to claim 1, characterized in that, The curing agent is an HDI trimer curing agent, with the brand name Wanhua HT-100, Wanhua HT-600, and Tosoh HRX-90B; the solvent is one of ethyl acetate, butyl acetate, toluene, and xylene.

7. The coating for localized spraying of carbon fiber composite materials according to claim 1, characterized in that, In S1, the mass-to-volume ratio of calcium boride micro powder to sodium hydroxide solution is 1 g:(15-25) mL; the mass-to-volume ratio of active calcium boride, γ-glycidyl etheroxypropyltrimethoxysilane and ethanol is 1 g:(0.15-0.35) g:(15-25) mL.

8. The coating for localized spraying of carbon fiber composite materials according to claim 1, characterized in that, In S2, the mass-to-volume ratio of tetrahydrofuran acrylate, 4,6-diamino-2-mercaptopyrimidine, and N,N-dimethylformamide is (0.26-0.52) g:(0.22-0.44) g:(10-20) mL.

9. The coating for localized spraying of carbon fiber composite materials according to claim 1, characterized in that, In S3, the mass-to-volume ratio of epoxy borate calcium, thioether compound, triethylamine and anhydrous ethanol is 1 g:(0.37-0.59) g:(0.003-0.008) g:(20-30) mL.

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