Preparation method of carbon fiber composite frame

Abstract

The invention relates to a preparation method of a carbon fiber composite frame, and belongs to the field of carbon fiber composites.The carbon fiber composite frame comprises a core material and a carbon fiber sheet located on the surface of the core material.The preparation method comprises the steps that the surface of the core material is modified so as to activate the surface of the core material and increase the surface energy of the core material; attaching microsphere resin to the surface of the core material; wrapping the surface of the core material with a carbon fiber sheet, and extruding the microsphere resin to form a frame blank; and curing the vehicle frame blank to obtain the carbon fiber composite material vehicle frame. According to the carbon fiber composite frame, the carbon fiber sheet and the core material are bonded through the microsphere resin, in the time period from liquidity reduction to complete curing after the microsphere resin is heated, expansion microspheres in the resin begin to be heated and expanded, in this way, a porous structure is formed after the resin is cured, and compared with traditional solid resin, the weight and density are reduced, and the service life of the carbon fiber composite frame is prolonged. And the expanded microspheres which become large are elastic and can absorb vibration impact, so that the toughness of the frame is improved, and the problem of brittle fracture is solved.

Description

Technical Field

[0001] This application relates to the field of carbon fiber composite materials, and in particular to a method for preparing a carbon fiber composite vehicle frame. Background Technology

[0002] Currently, wheelchairs in existing technologies are generally made of stainless steel or aluminum alloy. Stainless steel wheelchairs are heavy and inconvenient to carry, while aluminum alloy wheelchairs are lightweight but more expensive.

[0003] For wheelchair users, choosing a lightweight wheelchair is the most important consideration when purchasing one, and it is the primary requirement for wheelchairs. A lighter wheelchair is obviously a better choice, as it is not only easier to move and use, but it also means that it will be easier to operate.

[0004] The frame is a major component of a wheelchair. Traditional metal wheelchair frames have many welding points and are not aesthetically pleasing, which affects wheelchair sales.

[0005] Although some manufacturers have tried to use carbon fiber composite materials to make frames in order to improve the aesthetics of the frames and further reduce weight, the carbon fiber composite frames produced are prone to brittle fracture and easy peeling of carbon fiber layers during use due to limitations in manufacturing technology. This has resulted in the slow development of carbon fiber composite frames and their inability to replace metal frames as the mainstream in the industry. Summary of the Invention

[0006] In order to address the problems of current carbon fiber composite vehicle frames mentioned in the background art, this application provides a method for preparing a carbon fiber composite vehicle frame.

[0007] The method for preparing a carbon fiber composite vehicle frame provided in this application adopts the following technical solution: A method for preparing a carbon fiber composite vehicle frame, the carbon fiber composite vehicle frame comprising a core material and carbon fiber sheets located on the surface of the core material, the preparation method comprising: The core material surface is modified to activate the core material surface and increase its surface energy; Microsphere resin is attached to the surface of the core material; The core material is wrapped with carbon fiber sheets and microsphere resin is extruded to form a frame preform. The frame preform is cured to obtain a carbon fiber composite frame.

[0008] By adopting the above technical solution, carbon fiber sheets and core materials are bonded together using microsphere resin. During the period from when the fluidity of the microsphere resin begins to decrease after being heated to when it is fully cured, the expanded microspheres in the resin begin to expand due to heat. In this way, the resin forms a porous structure after curing. Compared with traditional solid resin, this not only reduces weight and density, but also makes the larger expanded microspheres more elastic, able to absorb vibration and impact, improve the toughness of the frame, and solve the problem of brittle fracture.

[0009] Preferably, the surface modification treatment of the core material includes: Immerse the core material in a surface treatment agent or apply the surface treatment agent to the surface of the core material; Dry the core material; The surface treatment agent is an ethanol solution containing silica treated with low-temperature plasma or a diluted weakly polar epoxy resin solution. The mass fraction of silica in the ethanol solution is 0.5%-2%; The weakly polar epoxy resin diluent contains a non-polar / weakly polar solvent.

[0010] By adopting the above technical solution, the surface of polyurethane is activated and its surface energy is increased, so that the microsphere resin and polyurethane generate extremely strong mechanical interlocking force and chemical bonding force, ensuring that the interface between the two is firmly bonded and effectively solving the problem of easy peeling of carbon fiber layer.

[0011] Preferably, the microsphere resin is an epoxy resin containing expanded microspheres and a curing agent, wherein the volume percentage of the expanded microspheres in the epoxy resin is 1%-5%, and the particle size of the expanded microspheres is 10-50 μm. During the period from when the flowability of epoxy resin begins to decrease after being heated to when it is fully cured, the expanding microspheres gradually expand due to heat.

[0012] By adopting the above technical solution, carbon fiber sheets and core materials are bonded together using microsphere resin. During the period from when the fluidity of the microsphere resin begins to decrease after being heated to when it is fully cured, the expanded microspheres in the resin begin to expand due to heat. In this way, the resin forms a porous structure after curing. Compared with traditional solid resin, this not only reduces weight and density, but also makes the larger expanded microspheres more elastic, able to absorb vibration and impact, improve the toughness of the frame, and solve the problem of brittle fracture.

[0013] Preferably, the step of wrapping the core material surface with carbon fiber sheets and extruding microsphere resin to form the frame preform includes: A layer of carbon fiber sheet is attached to the surface of the core material, and then the core material is placed in a pre-molded mold for molding to extrude microsphere resin. The components are installed into the core material, and then the core material is placed in the pre-molded mold and the mold is closed again. Several layers of carbon fiber sheets are attached to the surface of the core material. After each layer of carbon fiber sheet is attached, the core material is placed in a pre-molded mold for molding. After molding, the core material is weighed until the weight reaches the set target.

[0014] By adopting the above technical solution, a high-quality vehicle frame blank is obtained.

[0015] Preferably, the step of curing the frame preform to obtain a carbon fiber composite frame includes: A zoned temperature-controlled mold is used to cure the frame blank in different zones at different temperatures. The curing temperature of the high-stress zone of the frame is higher than that of the main beam tube zone. Cool the entire frame to the demolding temperature; The frame undergoes post-processing.

[0016] By adopting the above technical solutions, the internal stress of the frame is reduced, making the frame quality stable and reliable.

[0017] Preferably, the step of using a zoned temperature-controlled mold to perform zoned temperature-controlled curing of the vehicle frame preform includes: The entire frame blank is heated to temperature A and kept at that temperature for a period of time to allow the microspheres to fully expand due to heat, wherein 90℃≤TemperatureA≤113℃; The high-stress area of ​​the frame is heated to temperature B and kept at that temperature for a period of time until the entire frame blank is completely cured, wherein 120.3℃≤Temperature B≤139.1℃.

[0018] By adopting the above technical solution, the higher curing temperature in the high-stress area of ​​the frame results in a higher cross-linking density of the epoxy resin in that area, thereby achieving higher strength and rigidity. Meanwhile, the main beam tube area avoids the problem of poor toughness caused by high cross-linking due to excessive temperature while ensuring full curing. It also reduces internal stress caused by excessive temperature difference.

[0019] Preferably, the partitioned temperature control mold includes: Positioning blocks are used for positioning the vehicle frame blank; The upper mold has an upper frame groove, an upper positioning block groove, and an overflow groove on its lower surface. The upper frame groove is designed to accommodate the upper part of the frame blank, the upper positioning block groove is designed to accommodate the upper part of the positioning block, and the overflow groove is located on both sides of the upper frame groove and extends synchronously with the upper frame groove. The lower mold has a lower frame groove and a lower positioning block groove on its upper surface. The lower frame groove is designed to accommodate the lower part of the frame blank, and the lower positioning block groove is designed to accommodate the lower part of the positioning block.

[0020] By adopting the above technical solution, the vehicle frame blank can be solidified.

[0021] Preferably, the core material is a modified MDI series polyurethane.

[0022] By adopting the above technical solution, it meets the requirements for carbon fiber molding.

[0023] In summary, this application includes at least one of the following beneficial technical effects: The carbon fiber composite frame of this application uses polyurethane as the core material to ensure the frame is lightweight. By modifying the surface of the core material, the surface of the polyurethane is activated and its surface energy is increased, so that the microsphere resin and polyurethane generate extremely strong mechanical interlocking force and chemical bonding force, ensuring that the interface between the two is firmly bonded and effectively solving the problem of easy peeling of carbon fiber layer.

[0024] The carbon fiber composite frame of this application uses microsphere resin to bond carbon fiber sheets and core materials. During the period from when the fluidity of the microsphere resin begins to decrease after being heated to when it is fully cured, the expanded microspheres in the resin begin to expand due to heat. In this way, the resin forms a porous structure after curing. Compared with traditional solid resin, it not only reduces weight and density, but also the larger expanded microspheres are elastic and can absorb vibration and impact, thereby improving the toughness of the frame and solving the problem of brittle fracture. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the partitioned temperature control mold.

[0026] Figure 2 It was an explosion of a temperature-controlled mold. Figure 1 .

[0027] Figure 3 It was an explosion of a temperature-controlled mold. Figure 2 .

[0028] Figure 4 This is a structural diagram of a carbon fiber composite frame.

[0029] Figure 5 This is a schematic diagram of the installation of a carbon fiber composite frame.

[0030] Figure 6 This is a schematic diagram of the lower mold structure.

[0031] Explanation of reference numerals in the attached figures: 1. Lower mold; 11. Lower frame slot; 12. Lower positioning block slot; 2. Upper mold; 21. Upper frame groove; 22. Upper positioning block groove; 23. Grease overflow groove; 3. Frame; 31. Core material; 32. Carbon fiber sheet; 33. Sleeve; 4. Positioning block. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0033] This application discloses a method for preparing a carbon fiber composite vehicle frame, including: S1. Surface modification treatment of core material 31 to activate the surface of core material 31 and increase its surface energy; S2. Attach the microsphere resin to the surface of the core material 31; S3. Wrap the surface of the core material 31 with carbon fiber sheet and extrude microsphere resin to form a frame preform; S4. The frame preform is cured to obtain a carbon fiber composite frame 3.

[0034] Specifically, such as Figure 4 As shown, the carbon fiber composite frame 3 includes a core material 31 and carbon fiber sheets located on the surface of the core material 31. Preferably, the carbon fiber sheets are carbon fiber cloth, and the core material 31 is made of modified MDI series polyurethane. Modified MDI series polyurethane has the following characteristics: 1. High temperature resistance, meeting the requirements for carbon fiber molding under high temperature conditions of 160-180℃.

[0035] 2. Low density and light weight, molded core material with a density of 150kg / cm3-300kg / cm3 can be made according to customer needs 31; 3. It can be formed by shaping mold, which facilitates the 32-layer wrapping operation of carbon fiber sheets, improves production efficiency, and solves the problem of difficult processing and forming of special irregular parts; 4. Made of environmentally friendly materials, complying with RoHS, REACH and other environmental regulations; 5. Can be used for long-term use in environments with temperatures ranging from -30℃ to 70℃.

[0036] As can be seen, in this embodiment, polyurethane is used as the core material 31 to ensure that the frame 3 is lightweight. By modifying the surface of the core material 31, the surface of the polyurethane is activated and its surface energy is increased, so that the microsphere resin and polyurethane generate extremely strong mechanical interlocking force and chemical bonding force, ensuring that the interface between the two is firmly bonded and effectively solving the problem of easy peeling of the carbon fiber layer.

[0037] In addition, by using microsphere resin to bond carbon fiber sheet 32 ​​and core material 31, during the period from when the fluidity of the microsphere resin begins to decrease after being heated to when it is fully cured, the expanded microspheres in the resin begin to expand when heated. In this way, the resin forms a porous structure after curing. Compared with traditional solid resin, it not only reduces weight and density, but also the larger expanded microspheres are elastic and can absorb vibration and impact, improving the toughness of the frame 3 and solving the problem of brittle fracture.

[0038] Specifically, the surface modification treatment of core material 31 in S1 includes: S11. Immerse the core material 31 in the surface treatment agent or apply the surface treatment agent to the surface of the core material 31; S12. Dry the core material 31.

[0039] The surface treatment agent is an ethanol solution containing silica treated with low-temperature plasma or a diluted solution of weakly polar epoxy resin.

[0040] Low-temperature plasma refers to plasma with a low temperature, close to room temperature, so it will not burn the core material 31.

[0041] Silica itself has very small particle size and high surface energy, making it prone to agglomeration into large clumps. When these clumps are poured into an ethanol solution, the silica cannot be evenly dispersed and will either sink or clump together, failing to achieve its intended effect. Therefore, silica is treated with low-temperature plasma, which involves placing the silica in a low-temperature plasma environment. The low-temperature plasma disperses the agglomerated silica and removes dirt and impurities from its surface. The high-energy particles in the plasma break the chemical bonds on the surface of the silica particles, creating numerous defects and active sites. These active sites quickly combine with oxygen or water vapor in the air to generate a large number of -OH hydroxyl groups (i.e., hydrophilic groups), significantly increasing the surface energy of the silica. Subsequently, after the silica comes into contact with the core material 31, it is firmly anchored to the polyurethane surface, increasing the surface roughness of the core material 31. After the microsphere resin adheres to the surface of the core material 31, it undergoes strong chemical bonding with the epoxy groups in the epoxy resin, resulting in extremely strong mechanical interlocking and chemical bonding forces between the microsphere resin and the polyurethane. This ensures a strong interfacial bond between the two and effectively solves the problem of easy peeling of the carbon fiber layer.

[0042] The mass fraction of silica in the ethanol solution is 0.5%-2%, and preferably, the ethanol solution is anhydrous ethanol.

[0043] The weakly polar epoxy resin diluent contains non-polar / weakly polar solvents, such as toluene and xylene as non-polar solvents, and MIBK, DIBK, and isophorone as weakly polar solvents.

[0044] Specifically, the immersion time of the core material 31 in the surface treatment agent in S11 depends on the shape of the core material 31. When the core material 31 is as follows... Figure 4 As shown, the immersion time shall not be less than 1 minute. If the surface treatment agent is applied to the surface of the core material 31, the coating thickness shall not be less than 2 mm.

[0045] To shorten the drying time, the S12 core material 31 can be placed in a high-temperature environment, such as 80°C, for rapid drying.

[0046] In this embodiment, in S2, attaching the microsphere resin to the surface of the core material 31 can be done by immersing the core material 31, which has been dried in S12, into the microsphere resin, or by brushing the microsphere resin onto the surface of the core material 31 with a coating thickness of not less than 5 mm.

[0047] Specifically, the microsphere resin is an epoxy resin containing expanded microspheres and a curing agent. The expanded microspheres are thermoplastic hollow polymer microspheres composed of a thermoplastic polymer shell encapsulating liquid alkane gas. The volume percentage of the expanded microspheres in the epoxy resin is 1%-5%, and the particle size of the expanded microspheres is 10-50 μm. During the period from when the flowability of the epoxy resin begins to decrease after heating to when it is fully cured, the expanded microspheres gradually expand due to heating. That is, the expanded microspheres have already undergone significant expansion even before the epoxy resin has cured.

[0048] By using microsphere resin to bond carbon fiber sheet 32 ​​and core material 31, during the period from when the fluidity of the microsphere resin begins to decrease after being heated to when it is fully cured, the expanded microspheres in the resin begin to expand due to heat. In this way, the resin forms a porous structure after curing. Compared with traditional solid resin, this not only reduces weight and density, but also makes the larger expanded microspheres more elastic, able to absorb vibration and impact, improve the toughness of the frame 3, and solve the problem of brittle fracture.

[0049] In this embodiment, S3 wraps the surface of the core material 31 with carbon fiber sheet and extrudes microsphere resin to form a frame preform, including: S31. A layer of carbon fiber sheet is attached to the surface of the core material 31, and then the core material 31 is placed in a pre-molded mold for molding to extrude microsphere resin. S32. Install the accessories into the core material 31, and then place the core material 31 in the preform mold and close the mold again; S33. Several layers of carbon fiber sheets are attached to the surface of the core material 31. After each layer of carbon fiber sheet is attached, the core material 31 is placed in a pre-molded mold for molding. After molding, the weight is weighed until the weight reaches the set target.

[0050] Specifically, when attaching carbon fiber sheets to the surface of core material 31, S31 must ensure that the carbon fiber sheets are firmly attached. During the attachment process, the positioning must be accurate and no sheets should be missed. After attachment, the sheets are placed in a pre-molded mold for molding to compress the microsphere resin and ensure that the carbon fiber sheets are firmly attached.

[0051] Specifically, the components in S32 include metal parts for the upper and lower cross tubes, metal parts for the handlebar tubes and front wheel rims, metal parts for the upper and lower cross tube coils, and sleeve 33, such as... Figure 4 As shown, the above-mentioned components are located at the connection between the carbon fiber composite frame 3 and other parts. They are easily worn parts, so they are made of lightweight metals such as aluminum alloys. This can minimize the weight of the frame 3 and ensure the service life of the frame 3.

[0052] Specifically, in S33, after each layer of carbon fiber sheet is attached to the surface of the core material 31, the mold is closed and shaped to ensure the attachment quality of each layer of carbon fiber sheet, thereby obtaining a high-quality frame blank. The specific number of attachment layers depends on the design requirements of the frame 3.

[0053] In this embodiment, S4 involves curing the frame preform to obtain the carbon fiber composite frame 3, including: S41. The frame blank is cured in different zones using a zoned temperature-controlled mold. The curing temperature of the high-stress zone of the frame 3 is greater than that of the main beam tube zone. S42. Cool the entire frame 3 to the demolding temperature; S43. Perform post-processing on frame 3.

[0054] The zoned temperature curing process has the advantage of reducing the internal stress of the frame 3, making the frame 3 stable and reliable in quality.

[0055] Specifically, S41 describes the use of a zoned temperature-controlled mold for zoned temperature-controlled curing of the vehicle frame preform, which includes: S411. The entire frame preform is heated to temperature A and held at that temperature for a period of time to allow the microspheres to fully expand under heat. Within this temperature range, the microspheres can be heated and expanded quickly, while the resin is kept at a low curing rate to prevent the resin from curing rapidly before the microspheres have fully expanded. Moreover, at this temperature, the resin viscosity is reduced, allowing it to flow fully and impregnate the carbon fibers, thus completing the defoaming process. During the holding period, the resin system will undergo preliminary cross-linking (pre-gelling), which will basically stabilize the preform and minimize internal stress. Preferably, temperature A is 111℃, and the holding time is not less than 24 minutes. 111℃ provides the optimal expansion temperature for the expandable microspheres at the lowest cost, resulting in high expansion efficiency and good expansion effect. At the same time, the resin also has a curing rate adapted to the expansion of the microspheres. After the expandable microspheres have fully expanded, the resin begins to gradually cure. The minimum sufficient holding time ensures that the resin system is fully cross-linked, thus significantly reducing the stress within the preform.

[0056] S412. The high-stress area of ​​frame 3 is heated to temperature B and held at this temperature for a period of time until the entire frame preform is completely cured. Within this temperature range, 120.3℃ ≤ temperature B ≤ 139.1℃. In this range, the resin in the high-stress area of ​​frame 3 cures rapidly and completely at a higher curing temperature. This higher curing temperature maximizes the resin crosslinking density, resulting in higher strength, modulus, and glass transition temperature. Meanwhile, other areas outside the high-stress area of ​​frame 3, such as the main beam tube area, continue to be cured at a lower temperature (A) until the entire frame preform is completely cured. The relatively lower temperature at which other areas outside the high-stress area of ​​frame 3 cure avoids the brittleness that may result from excessive crosslinking and, most importantly, prevents the generation of large internal stresses due to temperature differences with the high-stress area.

[0057] Preferably, temperature B is 135℃, and the holding time is not less than 50 hours. The high temperature of 135℃ allows the resin in the high-stress area to cure rapidly, and the high-stress area of ​​the frame 3 obtains optimal strength, modulus and glass transition temperature, perfectly matching its high stress requirements. The minimum sufficient holding time avoids the brittleness caused by excessive cross-linking and avoids huge internal stress due to temperature difference.

[0058] In the specific implementation of S41, the entire frame preform is first heated to a relatively low temperature A and held at this temperature for a period of time. At this temperature, the expandable microspheres begin to expand due to heat, the flowability of the epoxy resin begins to decrease, and it slowly begins to cure. The slow and prolonged curing of the main beam tube area at temperature A ensures full curing while avoiding the problem of poor toughness caused by high cross-linking due to excessively high temperatures. At the same time, it reduces internal stress caused by excessive temperature differences, improving the stability and durability of the frame 3. After the expandable microspheres have fully expanded due to heat, the high-stress area of ​​the frame 3 is raised from temperature A to temperature B. This allows the epoxy resin in the high-stress area of ​​the frame 3 to have a higher cross-linking density at a higher curing temperature, thereby obtaining higher strength and rigidity.

[0059] In this embodiment, zoned temperature curing is achieved through a zoned temperature-controlled mold, such as... Figures 1-3 , Figure 5 and Figure 6As shown, the partitioned temperature control mold includes: a positioning block 4, an upper mold 2, and a lower mold 1. The positioning block 4 is used for positioning the frame blank to ensure that the frame blank is firmly fixed in the upper mold 2 and the lower mold 1. The lower surface of the upper mold 2 is constructed with an upper frame groove 21, an upper positioning block groove 22, and an overflow groove 23. The upper frame groove 21 is constructed to accommodate the upper part of the frame blank, and the upper positioning block groove 22 is constructed to accommodate the upper part of the positioning block 4. The overflow groove 23 is located on both sides of the upper frame groove 21 and extends synchronously with the upper frame groove 21. The overflow groove 23 is used for resin that is squeezed out of the frame blank after mold closing to flow into it. The upper surface of the lower mold 1 is constructed with a lower frame groove 11 and a lower positioning block groove 12. The lower frame groove 11 is constructed to accommodate the lower part of the frame blank, and the lower positioning block groove 12 is constructed to accommodate the lower part of the positioning block 4.

[0060] In addition, both the upper mold 2 and the lower mold 1 are provided with flow channels (not shown in the figure). The flow channel inside the upper mold 2 is used to introduce liquid at temperature B to perform high-temperature curing on the high-stress area of ​​the frame 3. Of course, liquid at temperature A can also be introduced at the beginning of the curing process. After the microspheres are fully heated and expanded, liquid at temperature B can be introduced. The flow channel inside the lower mold 1 is used to introduce liquid at temperature A to perform low-temperature long-term full curing on the remaining main beam tube area of ​​the frame 3, except for the high-stress area.

[0061] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0062] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for producing a carbon fiber composite material frame, the carbon fiber composite material frame comprising a core material and a carbon fiber sheet material on the surface of the core material, characterized by, The preparation method comprises: surface modification treatment of the core material to activate the surface of the core material and increase the surface energy thereof; attaching microsphere resin to the surface of the core material; wrapping the surface of the core material with carbon fiber sheet and extruding the microsphere resin to form a frame blank; curing the frame blank to obtain a carbon fiber composite frame.

2. The method of claim 1, wherein: The surface modification treatment of the core material comprises: immersing the core material in a surface treatment agent or applying the surface treatment agent to the surface of the core material; drying the core material; the surface treatment agent is an ethanol solution containing white carbon black treated by low-temperature plasma or a dilute solution of weakly polar epoxy resin; the mass fraction of white carbon black in the ethanol solution is 0.5%-2%; the dilute solution of weakly polar epoxy resin contains non-polar / weakly polar solvent.

3. The method of claim 1, wherein: The microsphere resin is epoxy resin containing expanded microspheres and curing agent, the volume fraction of the expanded microspheres in the epoxy resin is 1%-5%, and the particle size of the expanded microspheres is 10-50μm; the expanded microspheres gradually expand under heat within the time period from the start of the decrease in the flowability of the epoxy resin to complete curing.

4. The method of claim 1, wherein: The wrapping of the surface of the core material with carbon fiber sheet and the extrusion of the microsphere resin to form a frame blank comprises: attaching a layer of carbon fiber sheet to the surface of the core material, and then placing the core material in a preform mold for molding to extrude the microsphere resin; mounting accessories to the core material, and then placing the core material in the preform mold for molding again; attaching several layers of carbon fiber sheet to the surface of the core material, and then placing the core material in the preform mold for molding after attaching each layer of carbon fiber sheet, and weighing after molding until the weight reaches the set target.

5. The method of claim 1, wherein: The curing of the frame blank to obtain a carbon fiber composite frame comprises: adopting a partition temperature control mold to cure the frame blank in partitions and at different temperatures, wherein the curing temperature of the high stress area of the frame is higher than the curing temperature of the main beam tube area; cooling the frame as a whole to demolding temperature; post-processing the frame.

6. The method of claim 5, wherein: The curing of the frame blank in partitions and at different temperatures by using the partition temperature control mold comprises: heating the frame blank as a whole to temperature A and keeping the temperature for a period of time to make the expanded microspheres fully expand under heat, wherein 90℃≤temperature A≤113℃; heating the high stress area of the frame to temperature B and keeping the temperature for a period of time until the frame blank is completely cured, wherein 120.3℃≤temperature B≤139.1℃.

7. The method for preparing a carbon fiber composite vehicle frame according to claim 5, characterized in that: The partition temperature control mold comprises: a positioning block for positioning the frame blank; an upper mold, the lower surface of which is configured with an upper frame groove, an upper positioning block groove and a grease overflow groove, the upper frame groove is configured to accommodate the upper part of the frame blank, the upper positioning block groove is configured to accommodate the upper part of the positioning block, and the grease overflow groove is located at the two side groove edges of the upper frame groove and extends synchronously with the upper frame groove; a lower mold, the upper surface of which is configured with a lower frame groove and a lower positioning block groove, the lower frame groove is configured to accommodate the lower part of the frame blank, and the lower positioning block groove is configured to accommodate the lower part of the positioning block.

8. The method of claim 1, wherein: The core material is modified MDI series polyurethane.

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