A rapid composite process for thermoset composite and plastic assembly structure

Abstract

This application relates to the field of composite material processing, specifically disclosing a rapid composite process for thermosetting composite materials and plastic assembly structures. The composite process includes the following steps: applying a primer to the composite surface of a thermosetting carbon fiber resin composite material to obtain a preform; placing the preform in a mold and using insert injection molding to composite the plastic onto the preform to obtain a composite structure; the primer comprises the following components by weight: 15-25 parts epoxy resin, 75-85 parts ethyl acetate, 15-20 parts acetone, and 75-80 parts polyisocyanate; the thermosetting carbon fiber composite material is an epoxy resin-based thermosetting carbon fiber composite material; and the plastic is polycarbonate plastic. This application not only improves the bonding strength of the plastic in the thermosetting carbon fiber composite material but also increases production efficiency.

Description

Technical Field

[0001] This application relates to the field of composite material processing, and more specifically, it relates to a rapid composite process and composite structure for thermosetting composite materials and plastic assembly structures. Background Technology

[0002] The manufacturing process of composite products made from thermosetting composite materials and plastics typically involves bonding the thermosetting composite material product and the plastic structure together using adhesives, such as epoxy resin. However, this manufacturing process has the following problems: the curing time of the adhesive is generally long, resulting in low production efficiency. Summary of the Invention

[0003] To improve the production efficiency of combining thermosetting composite materials with plastic assembly structures, this application provides a rapid composite process and composite structure for combining thermosetting composite materials with plastic assembly structures.

[0004] This application provides a rapid composite process for thermosetting composite materials and plastic assembly structures, employing the following technical solution:

[0005] A rapid bonding process for thermosetting composite materials and plastic assembly structures includes the following steps:

[0006] A primer is applied to the composite surface of a thermosetting carbon fiber resin composite material to obtain a preform; the preform is placed in a mold, and plastic is laminated onto the preform using insert injection molding to obtain a composite structure.

[0007] The raw materials of the primer include the following components by weight: 15-25 parts epoxy resin, 75-85 parts ethyl acetate, 15-20 parts acetone, and 75-80 parts polyisocyanate.

[0008] The thermosetting carbon fiber resin composite material is an epoxy resin-based thermosetting carbon fiber resin composite material; the plastic is a polycarbonate plastic.

[0009] By adopting the above technical solution, this application coats the primer onto the composite surface of the thermosetting carbon fiber resin composite material. The primer can cure quickly, and then the thermosetting carbon fiber resin composite material and plastic can be directly bonded together by insert injection molding, which can greatly improve production efficiency.

[0010] In addition, in the primer of this application, epoxy resin and ethyl acetate are the main components of the adhesive. After the primer is applied to the composite material, acetone dissolves the epoxy resin on the surface of the composite material, allowing the epoxy resin in the primer and the epoxy resin in the composite material to fully fuse, preparing for the bonding between the primer and the composite material. Simultaneously, in this application, acetone acts as a solvent, while acetone and polyisocyanate act as curing agents, enabling the primer to cure quickly and bond to the composite material. Furthermore, the polyisocyanate in this application can also improve the bonding strength between the primer and the composite material. Considering that the primer contains acetone and epoxy resin, this application uses polycarbonate as the plastic, which allows for better bonding between the plastic and the composite material. Therefore, this application utilizes a combination of primer and insert injection molding, which not only improves the bonding strength of the plastic in the thermosetting carbon fiber resin composite material but also increases production efficiency.

[0011] Preferably, the curing temperature of the primer on the thermosetting carbon fiber resin composite material is 80±5℃, and the curing time is 30±5min. More preferably, the thickness of the cured primer is 30-50µm. Even more preferably, the thermosetting temperature of the epoxy resin in the thermosetting carbon fiber resin composite material is 160-180℃, and the molding temperature of the plastic is 220-280℃.

[0012] By adopting the above technical solution, the curing and injection molding conditions of this application work in conjunction with the primer components. During the curing process of the primer, the polyisocyanate mainly undergoes a self-polymerization reaction, while the dissolving effect of acetone and the bonding effect of polyisocyanate combine to initially bond the primer to the composite material. During the insert injection molding process, the temperature of the plastic is transferred to the primer and the composite material. Under the action of acetone, the uncured epoxy resin dissolves, allowing the primer, composite material, and plastic to fuse well together. Moreover, during this process, polyisocyanate and epoxy resin undergo a ring-opening reaction, gradually generating oxazolidinone. In addition, isocyanurate generated by the self-polymerization of polyisocyanate also undergoes ring-opening with epoxy resin to gradually generate oxazolidinone. Thus, while the plastic fully wets the surface of the composite material, the plastic is fully bonded to the composite material through the primer, effectively improving the bonding strength between the composite material and the primer. Therefore, this application, while performing normal insert injection molding operations, also ensures that the primer fully bonds the composite material and the plastic together, improving production efficiency.

[0013] Preferably, the raw materials of the primer further include the following components: 10-19 parts of silica sol and 2-5 parts of epoxy silane coupling agent. More preferably, the silica sol has a solid content of 29-31% and an average particle size of 7-16 nm.

[0014] By adopting the above technical solutions, the addition of silica sol to the primer can effectively improve the bonding strength between the primer and the composite material. Furthermore, the silica sol exhibits excellent permeability; after the epoxy resin in the composite material is dissolved in acetone, the silica sol penetrates into the voids of the composite material, fully bonding with it. The epoxy-based silane coupling agent has good compatibility with the epoxy resin, promoting the bonding between the epoxy resin in the primer and the epoxy resin in the composite material. Additionally, this application uses silica sol with a specific solid content. This reduces the impact of moisture in the silica sol on the primer system. Furthermore, the epoxy-based silane coupling agent in this application can undergo hydrolysis to generate silanol groups, consuming the moisture in the silica sol. Moreover, after the epoxy resin on the composite material is dissolved in acetone, the silanol groups can condense with the hydroxyl groups in the composite material to form siloxane bonds. These siloxane bonds have high bond energy, significantly improving the bonding strength between the primer and the composite material.

[0015] Preferably, the preparation method of the thermosetting carbon fiber resin composite material includes the following steps: soaking carbon fiber in concentrated nitric acid for 110-120 minutes, drying and washing to obtain modified carbon fiber; mixing epoxy resin and curing agent evenly, then pouring epoxy resin into a mold containing modified carbon fiber, wherein the mass ratio of epoxy resin to modified carbon fiber is 10-11:9, and after curing, obtaining the thermosetting carbon fiber resin composite material.

[0016] By adopting the above-mentioned technical solutions, surface oxidation of carbon fibers can increase the active groups on the carbon fiber surface, which can effectively improve the dispersibility of carbon fibers in epoxy resin, thereby improving the performance of the composite material. Furthermore, in this application, appropriate oxidation with concentrated nitric acid allows the carbon fiber surface to possess more hydroxyl groups, enabling the silanol groups formed by the epoxy silane coupling agent to bond well with the carbon fibers, further improving the bonding strength between the primer and the composite material. Additionally, excess polyisocyanate in the primer can also react with hydroxyl groups, increasing the bonding strength between the primer and the composite material.

[0017] Preferably, glass fibers are added to the plastic for modification, with the amount of glass fibers added being 20-45 wt% and the length of the glass fibers being 3-5 mm. More preferably, the method for modifying the plastic by adding glass fibers is as follows: a 0.25-0.3 mol / L sulfuric acid solution and a 0.25-0.3 mol / L hydrochloric acid solution are mixed at a volume ratio of 1:1 to obtain an acid etching solution; the glass fibers are placed in the acid etching solution and etched at 55-60°C for 1.3-1.4 hours to obtain modified glass fibers; the modified glass fibers are then mixed with the plastic to modify the plastic.

[0018] By adopting the above technical solutions, adding glass fibers to plastics can improve the strength of the plastics while reducing their shrinkage rate, thus improving product quality. Furthermore, this application controls the acid etching conditions, which on the one hand allows for the formation of microgrooves on the surface of the glass fibers, increasing the number of active groups; on the other hand, it does not excessively affect the mechanical properties of the glass fibers themselves, resulting in more uniform dispersion of the glass fibers in the plastic system and improving plastic performance. In addition, the inventors discovered that after adding silica sol and epoxy silane coupling agent to the primer and curing the primer at approximately 80±5℃, followed by injection molding of the plastic containing glass fibers, the bonding strength between the plastic and the composite material is significantly improved. The inventors speculate that this may be due to the condensation of silanol groups generated by the reaction of residual moisture and remaining epoxy silane coupling agent in the primer with the hydroxyl groups on the glass fibers. Additionally, excess polyisocyanate in the primer can also react with the hydroxyl groups on the glass fibers, increasing the bonding strength between the primer and the plastic.

[0019] Preferably, the composite surface of the thermosetting carbon fiber resin composite material is roughened before a primer is applied to the composite surface of the thermosetting carbon fiber resin composite material.

[0020] By adopting the above technical solution, the bonding strength of the primer on the composite material can be further improved.

[0021] In summary, this application has the following beneficial effects:

[0022] 1. The primer of this application has a fast curing time. It can be cured in 30±5 minutes at 80±5℃, resulting in high production efficiency. Moreover, the bonding strength between the thermosetting carbon fiber resin composite material and the plastic is excellent.

[0023] 2. This application uses a primer with a thickness of only 30-50um, resulting in low material costs.

[0024] 3. The plastic structure is injection molded, eliminating the need for bonding tooling, which further reduces costs and improves production efficiency.

[0025] 4. This application optimizes the composition of the primer, modifies the plastic using glass fiber, and optimizes the preparation process of the thermosetting carbon fiber resin composite material, so that the glass fiber, carbon fiber, polyisocyanate, silica sol, epoxy silane coupling agent, etc. interact with each other, effectively improving the bonding strength between the primer and the plastic and the composite material. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the sample fixation structure used in the performance testing of this application.

[0027] Explanation of reference numerals in the attached drawings: 1. Sample; 2. Tooling; Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] Unless otherwise specified, all materials used in the preparation examples are commercially available, including T700 carbon fiber and E51 epoxy resin with an epoxy value of 0.52 mol / 100g and a density of 1.2 g / cm³. 3 The curing agent is diethyltoluenediamine.

[0030] Preparation Example 1

[0031] Preparation Example 1 provides a method for preparing a thermosetting carbon fiber resin composite material, comprising the following steps:

[0032] The surface of the carbon fiber was cleaned with acetone to remove impurities. After drying, the carbon fiber was soaked in concentrated nitric acid for 110 minutes, then dried at 120±5℃ for 2.1 hours, and finally cleaned with water to obtain modified carbon fiber.

[0033] Epoxy resin and modified carbon fiber were mixed in a mass ratio of 10:9. The modified carbon fiber was laid flat in a mold and dried at 100℃ for 30 min. Epoxy resin and ethyl toluene diamine curing agent were mixed in a mass ratio of 20:3.1 and then thoroughly mixed. The epoxy resin was then poured into the mold containing the modified carbon fiber. The temperature was raised to 100℃ and held for 1 h at a rate of 2.5℃ / min. The temperature was then raised to 160℃ and held for 1.6 h at a rate of 2.5℃ / min. Finally, the temperature was raised to 180℃ and held for 2 h at a rate of 1.6℃ / min. The mixture was then allowed to cool naturally to room temperature before demolding to obtain the thermosetting carbon fiber resin composite material.

[0034] Preparation Example 2

[0035] Preparation Example 2 provides a method for preparing a thermosetting carbon fiber resin composite material, comprising the following steps:

[0036] The surface of the carbon fiber was cleaned with acetone to remove impurities. After drying, the carbon fiber was soaked in concentrated nitric acid for 120 minutes, then dried at 120±5℃ for 2.1 hours, and finally cleaned with water to obtain modified carbon fiber.

[0037] Epoxy resin and modified carbon fiber were mixed in a mass ratio of 11:9. The modified carbon fiber was spread evenly in a mold and dried at 100℃ for 30 min. Epoxy resin and ethyl toluene diamine curing agent were mixed in a mass ratio of 20:3.1 and then thoroughly mixed. The epoxy resin was then poured into the mold containing the modified carbon fiber. The temperature was raised to 100℃ and held for 1 h at a heating rate of 2.5℃ / min. The temperature was then raised to 160℃ and held for 1.6 h at a heating rate of 2.5℃ / min. Finally, the temperature was raised to 180℃ and held for 2 h at a heating rate of 1.6℃ / min. The mixture was then allowed to cool naturally to room temperature before demolding to obtain the thermosetting carbon fiber resin composite material.

[0038] Preparation Example 3

[0039] Preparation Example 3 provides a method for preparing a thermosetting carbon fiber resin composite material, comprising the following steps:

[0040] The carbon fiber surface is cleaned with acetone to remove impurities, and then dried to obtain carbon fiber.

[0041] Epoxy resin and carbon fiber were mixed in a mass ratio of 10:9. The carbon fiber was laid flat in a mold and dried at 100℃ for 30 min. Epoxy resin and ethyl toluene diamine curing agent were mixed in a mass ratio of 20:3.1 and then thoroughly mixed. The epoxy resin was then poured into the mold containing the carbon fiber. The temperature was raised to 100℃ and held for 1 h at a rate of 2.5℃ / min. The temperature was then raised to 160℃ and held for 1.6 h at a rate of 2.5℃ / min. Finally, the temperature was raised to 180℃ and held for 2 h at a rate of 1.6℃ / min. The mixture was then allowed to cool naturally to room temperature before demolding to obtain the thermosetting carbon fiber resin composite material.

[0042] Preparation Example 4

[0043] The difference between Preparation Example 4 and Preparation Example 1 is that the carbon fiber was soaked in concentrated nitric acid for 100 minutes.

[0044] Unless otherwise specified, all materials used in the preparation examples are commercially available. The glass fiber is alkali-free glass fiber with a nominal diameter of 14 micrometers and a length of 5 mm.

[0045] Preparation Example 5

[0046] Preparation Example 5 provides a method for preparing a plastic by adding glass fibers to modify the plastic. The operation method is as follows:

[0047] A 0.3 mol / L sulfuric acid solution and a 0.3 mol / L hydrochloric acid solution were mixed in a 1:1 volume ratio to obtain an acid etching solution. Glass fibers were placed in the acid etching solution and etched at 60°C for 1.4 hours. Then, the fibers were ultrasonically cleaned with acetone and dried at 60°C for 9 hours to obtain modified glass fibers.

[0048] The modified glass fiber is added to the plastic and mixed evenly to modify the plastic. The amount of modified glass fiber added is 45wt%, and the amount of plastic added is 55wt%.

[0049] Preparation Example 6

[0050] Preparation Example 6 provides a method for preparing a plastic by adding glass fibers to modify the plastic. The operation method is as follows:

[0051] A 0.25 mol / L sulfuric acid solution and a 0.25 mol / L hydrochloric acid solution were mixed in a 1:1 volume ratio to obtain an acid etching solution. Glass fibers were placed in the acid etching solution and etched at 55°C for 1.3 hours. Then, the fibers were ultrasonically cleaned with acetone and dried at 60°C for 9 hours to obtain modified glass fibers.

[0052] The modified glass fiber is added to the plastic and mixed evenly to modify the plastic. The amount of modified glass fiber added is 20 wt%, and the amount of plastic added is 80 wt%.

[0053] Preparation Example 7

[0054] Preparation Example 7 provides a method for preparing a plastic by adding glass fiber to modify the plastic. The operation method is as follows: glass fiber is added to the plastic and mixed evenly to modify the plastic. The amount of glass fiber added is 20 wt%, and the amount of plastic added is 80 wt%.

[0055] Preparation Example 8

[0056] The difference between Preparation Example 8 and Preparation Example 6 is that: 0.2 mol / L sulfuric acid solution and 0.2 mol / L hydrochloric acid solution were mixed in a volume ratio of 1:1 to obtain an acid etching solution. Glass fiber was placed in the acid etching solution and etched at 60°C for 1.6 hours. Then, it was ultrasonically cleaned with acetone and dried at 60°C for 9 hours to obtain modified glass fiber. Example

[0057] Example 1

[0058] Embodiment 1 of this application provides a rapid composite process for thermosetting composite materials and plastic assembly structures, including the following steps:

[0059] Primer formulation: The primer raw materials include the following components by weight: 20g epoxy resin, 80g ethyl acetate, 17g acetone, and 78g polyisocyanate; the polyisocyanate is isocyanate XH-L245 sold by Jining Huakai Resin Co., Ltd. The epoxy resin is E51 epoxy resin with an epoxy value of 0.52mol / 100g and a density of 1.2g / cm³. 3 .

[0060] Composite Process: The composite surface of the thermosetting carbon fiber resin composite material was roughened by sandblasting. A primer was applied to the roughened composite surface of the thermosetting carbon fiber resin composite material, and after curing, a preform was obtained. The curing temperature was 80℃, the curing time was 30 min, and the cured thickness was 30-50 μm. Then, the preform was placed in a mold, and the plastic was composited onto the preform using insert injection molding to obtain a composite structure. The molding temperature of the plastic was 280℃. The thermosetting carbon fiber resin composite material was from Preparation Example 1, and the plastic was from Preparation Example 6.

[0061] Example 2

[0062] The difference between Example 2 and Example 1 is that the raw materials of the primer include the following components by weight: 25g epoxy resin, 85g ethyl acetate, 20g acetone, and 80g polyisocyanate.

[0063] Example 3

[0064] The difference between Example 3 and Example 1 is that the raw materials of the primer include the following components by weight: 15g epoxy resin, 75g ethyl acetate, 15g acetone, and 75g polyisocyanate.

[0065] Example 4

[0066] The difference between Example 4 and Example 1 is that the raw materials for the primer also include 15g of silica sol and 3g of epoxy silane coupling agent. The silica sol has a solid content of 29-31% and an average particle size of 7-16nm, and is neutral AZN-830 silica sol purchased from Guangzhou Yangmei Chemical Co., Ltd.; the epoxy silane coupling agent is epoxy silane coupling agent KH-560.

[0067] Example 5

[0068] The difference between Example 5 and Example 1 is that the raw materials of the primer also include 10g of silica sol and 2g of epoxy silane coupling agent.

[0069] Example 6

[0070] The difference between Example 6 and Example 1 is that the raw materials of the primer also include 19g of silica sol and 5g of epoxy silane coupling agent.

[0071] Example 7

[0072] The difference between Example 7 and Example 4 is that the thermosetting carbon fiber resin composite material is derived from Preparation Example 2, and the plastic is derived from Preparation Example 7.

[0073] Example 8

[0074] The difference between Example 8 and Example 1 is that the thermosetting carbon fiber resin composite material is derived from Preparation Example 3.

[0075] Example 9

[0076] The difference between Example 9 and Example 4 is that the thermosetting carbon fiber resin composite material is derived from Preparation Example 3.

[0077] Example 10

[0078] The difference between Example 10 and Example 1 is that the thermosetting carbon fiber resin composite material is derived from Preparation Example 4.

[0079] Example 11

[0080] The difference between Example 11 and Example 4 is that the thermosetting carbon fiber resin composite material is derived from Preparation Example 4.

[0081] Example 12

[0082] The difference between Example 12 and Example 1 is that the plastic is derived from Preparation Example 7.

[0083] Example 13

[0084] The difference between Example 13 and Example 4 is that the plastic is derived from Preparation Example 7.

[0085] Example 14

[0086] The difference between Example 14 and Example 4 is that the plastic is derived from Preparation Example 8.

[0087] Example 15

[0088] The difference between Example 15 and Example 4 is that the curing temperature of the primer is 105°C.

[0089] Comparative Example 1

[0090] The difference between Comparative Example 1 and Example 1 is that an equal amount of ethyltoluene diamine is used to replace polyisocyanate in the primer.

[0091] Pull-out force test: Take sample 1 of the composite structure from the examples and comparative examples. After pretreatment, fix sample 1 between two test fixtures 2 using AB glue. The installation method is as follows: Figure 1 As shown in the figure, a pull-out test was then performed, and the test force when sample 1 peeled off was recorded. The test results are shown in Table 1.

[0092] The sample pretreatment method is as follows:

[0093] 1. High temperature resistance: After (90±2)℃*4H, the pull-out force is tested under normal temperature conditions.

[0094] 2. Heat aging: After (85±2)℃*240H, place at room temperature for 30 minutes and then perform a pull-out force test.

[0095] 3. Moisture resistance: (55±20)℃, relative humidity above 95%, 95H, after being placed at room temperature for 30 minutes, pull-out force test is performed.

[0096] Table 1. Test table of structural pull-out force performance for examples and comparative examples.

[0097]

[0098] As can be seen from the performance test results of Examples 1-3, the composite structure of this application has good bonding strength. Furthermore, the test results of Comparative Example 1 show that this is because polyisocyanate can improve the bonding strength between the primer and the composite material. Additionally, as shown in Example 15, with the processing technology of this application, polyisocyanate undergoes a self-polymerization reaction during the curing stage of the primer, initially bonding the primer to the composite material. Further, during insert injection molding, polyisocyanate can undergo a ring-opening reaction with epoxy resin, gradually generating oxazolidinone. Additionally, isocyanurate, generated by the self-polymerization of polyisocyanate, also undergoes ring-opening with epoxy resin to gradually generate oxazolidinone; effectively improving the bonding strength between the composite material and the primer.

[0099] The performance test results of Examples 4-6 show that the addition of silica sol and epoxy silane coupling agent allows the primer to better improve the bonding strength of the composite structure. Furthermore, combining the test results of Examples 8 and 9, it was found that when the carbon fiber was not oxidized, the performance of Examples 8 and 9 decreased. However, careful comparison revealed that the decrease in Example 8 compared to Example 1 was less than the decrease in Example 9 compared to Example 4. Therefore, the test results of Example 8 indicate that the increased surface activity of oxidized carbon fiber can improve the performance of thermosetting carbon fiber resin composites, thereby improving the performance of the composite structure. The performance test results of Example 9 show that the increased hydroxyl groups on the carbon fiber surface allow the silanol groups formed by the epoxy silane coupling agent to bond well with the carbon fiber. Additionally, excess polyisocyanate in the primer can also react with the hydroxyl groups, further improving the bonding strength between the primer and the composite material.

[0100] Furthermore, the test results of Examples 10 and 11 also show that the carbon fiber of Example 10 was oxidized, and therefore its performance was better than that of Example 8. However, the carbon fiber of Example 11 was also oxidized, but the performance of Example 11 and Example 9 was similar. This is because the carbon fiber of Examples 10 and 11 was poorly oxidized and did not have enough hydroxyl groups to provide for the action of epoxy silane coupling agent and polyisocyanate.

[0101] Similarly, as can be seen from the test results of Examples 12-14, after the glass fiber is oxidized, the hydroxyl and epoxy silane coupling agents and polyisocyanates can also act to better improve the bonding strength of the composite structure.

[0102] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A rapid composite process for thermosetting composite materials and plastic assembly structures, characterized in that: Includes the following steps: A primer is applied to the composite surface of a thermosetting carbon fiber resin composite material to obtain a preform. The pre-product is placed in a mold, and the plastic is laminated onto the pre-product using insert injection molding to obtain a composite structure. The raw materials of the primer include the following components by weight: 15-25 parts epoxy resin, 75-85 parts ethyl acetate, 15-20 parts acetone, and 75-80 parts polyisocyanate. The thermosetting carbon fiber resin composite material is an epoxy resin-based thermosetting carbon fiber resin composite material; the plastic is a polycarbonate plastic. The raw materials of the primer also include the following components: 10-19 parts of silica sol and 2-5 parts of epoxy silane coupling agent.

2. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 1, characterized in that: The curing temperature of the primer on the thermosetting carbon fiber resin composite material is 80±5℃, and the curing time is 30±5min.

3. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 2, characterized in that: The epoxy resin in the thermosetting carbon fiber resin composite material has a thermosetting temperature of 160-180℃, and the molding temperature of the plastic is 220-280℃.

4. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 2, characterized in that: The thickness of the cured primer is 30-50 μm.

5. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 1, characterized in that: The solid content of the silica sol is 29-31%, and the average particle size is 7-16 nm.

6. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 5, characterized in that: The preparation method of the thermosetting carbon fiber resin composite material includes the following steps: soaking carbon fiber in concentrated nitric acid for 110-120 minutes, drying and washing to obtain modified carbon fiber; mixing epoxy resin and curing agent evenly, then pouring epoxy resin into a mold containing modified carbon fiber, wherein the mass ratio of epoxy resin to modified carbon fiber is 10-11:9, and after curing, obtaining thermosetting carbon fiber resin composite material.

7. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 1, characterized in that: The plastic is modified by adding glass fiber, with the amount of glass fiber added being 20-45 wt% and the length of the glass fiber being 3-5 mm.

8. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 7, characterized in that: The method for modifying the plastic by adding glass fiber is as follows: a 0.25-0.3 mol / L sulfuric acid solution and a 0.25-0.3 mol / L hydrochloric acid solution are mixed at a volume ratio of 1:1 to obtain an acid etching solution. The glass fiber is placed in the acid etching solution and etched at 55-60°C for 1.3-1.4 hours to obtain modified glass fiber. The modified glass fiber is then mixed with the plastic to modify the plastic.

9. The rapid composite process for thermosetting composite materials and plastic assembly structures according to claim 1, characterized in that: The composite surface of the thermosetting carbon fiber resin composite material is roughened, and then a primer is applied to the composite surface of the thermosetting carbon fiber resin composite material.

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