Impact-resistant composite material for bicycle and preparation method of impact-resistant composite material

Abstract

The invention belongs to the technical field of material engineering, and particularly relates to an impact-resistant composite material for a bicycle and a preparation method of the impact-resistant composite material. Comprising the following components in parts by weight: 40-60 parts of epoxy resin, 20-35 parts of carbon fibers, 8-15 parts of basalt fibers, 5-10 parts of polyethylene fibers, 3-8 parts of bamboo charcoal fibers, 2-5 parts of nano silicon dioxide, 1-4 parts of titanium carbide, 4-9 parts of polyamide fibers, 4-10 parts of a curing agent, 1-3 parts of a dispersing agent and 2-6 parts of a toughening agent. According to the technical scheme, the transverse impact resistance and toughness of the composite material are greatly improved while the light characteristic of the composite material is kept, the defects that a traditional carbon fiber composite material is prone to breakage in the transverse direction and high in brittleness are overcome, and meanwhile the interface bonding force and the structural stability are enhanced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of material engineering, and particularly relates to a bicycle impact-resistant composite material and a preparation method thereof. BACKGROUND

[0002] With the popularization of the concept of green travel and the development of the bicycle movement, the performance requirements of bicycles on the market are increasingly improved, and lightweight, high strength and impact resistance have become the core development direction. Carbon fiber composite materials have gradually replaced traditional metal materials due to their low density, high specific strength and good formability, and are widely used in the manufacture of key components of high-end bicycles.

[0003] However, the existing carbon fiber composite materials have many technical defects in actual application: first, the transverse impact resistance is insufficient, and due to the limitation of the forming process, the material is prone to breakage under external impact, affecting the safety and service life of the bicycle; second, the toughness and strength are difficult to balance, and traditional carbon fiber composite materials are mostly brittle, with low elongation at break, and cannot absorb impact energy through deformation; third, the interfacial bonding force and structural stability are not good, the interfacial compatibility of the single resin matrix and carbon fibers is limited, and the fibers and resin are prone to peeling and delamination after long-term use, and the aging resistance and dimensional stability of the material need to be improved. At the same time, the existing improvement schemes also have limitations, some technical attempts try to improve the transverse performance by adding multiple fibers, but the fibers are simply mixed, the synergistic effect between the fibers is insufficient, and the toughness and interfacial bonding force are not targeted, and some other technologies use a single resin matrix and a conventional curing process, which makes it difficult for the material to meet the requirements of heat resistance and wear resistance in complex use scenarios.

[0004] Therefore, there is an urgent need for a bicycle impact-resistant composite material to solve the above problems. SUMMARY

[0005] To achieve the above-mentioned purpose, the following technical solutions are used: A bicycle impact-resistant composite material, by mass fraction, comprising the following components: epoxy resin 40-60 parts, carbon fiber 20-35 parts, basalt fiber 8-15 parts, polyethylene fiber 5-10 parts, bamboo charcoal fiber 3-8 parts, nano silicon dioxide 2-5 parts, titanium carbide 1-4 parts, polyamide fiber 4-9 parts, curing agent 4-10 parts, dispersing agent 1-3 parts, and toughening agent 2-6 parts.

[0006] Further, the single filament diameter of the basalt fiber is 8-12 microns, and the tensile strength is greater than or equal to 3500 MPa, and the particle size of the nano silicon dioxide is 50-100 nm.

[0007] A preparation method of a bicycle impact-resistant composite material, comprising the following steps: Step 100, raw material pretreatment, carbon fiber, basalt fiber polyethylene fiber is treated by fiber plasma, the bamboo charcoal fiber is treated by drying, and the nano silicon dioxide is modified by silane coupling agent KH-550; Step 200, first mixing, the pretreated carbon fiber, basalt fiber, polyethylene fiber, bamboo charcoal fiber, nano silicon dioxide, titanium carbide, polyamide fiber are put into the ball mill mixer, the dispersing agent is added, and the solid phase mixture is obtained by mixing; Step 300, second mixing, the epoxy resin is added into the reaction kettle, heated to melt, the toughening agent is added, stirred to completely dissolve, then the solid phase mixture is added, transferred to the high-speed mixer, and the initial mixture is obtained; Step 400, third mixing, the initial mixture is cooled, the curing agent is added, and the final mixture is obtained by stirring; Step 500, gradient curing forming treatment, the final mixture is injected into the mold, preheated, first kept warm, then heated, and finally cooled, naturally cooled to room temperature, and demolded, to obtain the composite material.

[0008] In step 100, during the fiber plasma treatment, argon atmosphere is used, the power is 300-500W, and the treatment time is 15-25min, and micro-nano holes are etched on the surface of the fiber.

[0009] Further, in step 100, during the drying treatment, it is dried at 120-150℃ for 4-6h; Further, the amount of silane coupling agent KH-550 is 3-5% of the mass of nano silicon dioxide, and the modification treatment is stirring at 60-80℃ for 2-3h.

[0010] Further, in step 200, during the first mixing treatment, the rotating speed is 80-100r / min, and the mixing time is 2-3h.

[0011] Further, in step 300, during the second mixing treatment, it is first heated to 60-80℃ to melt, the toughening agent is added, and then stirred at 300-500r / min for 30-60min until completely dissolved, then the solid phase mixture is added, transferred to the high-speed mixer, the rotating speed is adjusted to 180-220r / min, the temperature is 70-90℃, and the initial mixture is obtained by centrifugal mixing for 3-5h.

[0012] Further, in step 400, during the third mixing treatment, the initial mixture is cooled to 50-60℃, the curing agent is added, and stirred at 100-120r / min for 1-2h to ensure that the curing agent is uniformly dispersed in the initial mixture, and the final mixture is obtained.

[0013] Further, in step 500, during the gradient curing molding process, the final mixture is first injected into a mold preheated to 80-100℃, the mold pressure is controlled at 5-8MPa, first heat preservation at 120-140℃ for 2-3h, then heat to 180-200℃ at a rate of 5-10℃ / min, heat preservation for 4-6h, finally, heat to 80-100℃ at a rate of 3-5℃ / min, heat preservation for 1-2h, natural cooling to room temperature, then demolding, to obtain the composite material.

[0014] Compared with the prior art, the beneficial effects of the present application are: the technical scheme of the present application cooperates through the whole process of pretreatment, step-by-step mixing, gradient curing and post-treatment, so that the composite material greatly improves the transverse impact resistance and toughness while maintaining the lightweight property, solves the defects of traditional carbon fiber composite material, such as easy to break and strong brittleness in transverse direction, and strengthens the interface bonding force and structural stability. BRIEF DESCRIPTION OF DRAWINGS

[0015] Attached Figure 1 is the process flow chart of the preparation method in the present application. DETAILED DESCRIPTION

[0016] The present application will be further described in conjunction with the drawings and specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. In addition, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or modifications to the present application, and these equivalent forms also fall within the scope defined by the present application.

[0017] An impact-resistant composite material for bicycles, comprising the following components by mass fraction: epoxy resin 40-60 parts, carbon fiber 20-35 parts, basalt fiber 8-15 parts, polyethylene fiber 5-10 parts, bamboo charcoal fiber 3-8 parts, nano silicon dioxide 2-5 parts, titanium carbide 1-4 parts, polyamide fiber 4-9 parts, curing agent 4-10 parts, dispersing agent 1-3 parts, toughening agent 2-6 parts.

[0018] The epoxy resin serves as the resin matrix, exhibiting fluidity and heat resistance. This application utilizes a reinforcing fiber system composed of carbon fiber, basalt fiber, polyethylene fiber, and bamboo charcoal fiber. This composite structure forms a three-dimensional support system encompassing longitudinal, transverse, and overall dimensions. The basalt fiber has a single filament diameter of 8-12 μm and a tensile strength ≥3500 MPa to ensure transverse rigidity. Bamboo charcoal fiber improves the material's air permeability and adsorption properties, further enhancing its mechanical properties. Nano-silica and titanium carbide are used as functional fillers. The nano-silica has a particle size of 50-100 nm and, after modification with the silane coupling agent KH-550, exhibits significantly improved dispersion stability, uniformly filling the gaps in the reinforcing fiber system and enhancing the material's density. Furthermore, the synergistic use of nano-silica and titanium carbide improves the material's hardness and wear resistance. The polyamide fiber, curing agent, dispersant, and toughening agent serve as auxiliary additives to enhance stability, toughness, and the uniformity of each component.

[0019] In some preferred embodiments of this application, the toughening agent is a carboxyl-terminated nitrile butadiene rubber with a number-average molecular weight of 3000-5000 and a carboxyl content of 0.5-1 mmol / g, which can form elastic particles in the resin matrix to absorb impact energy. The curing agent is prepared by compounding 4,4'-diaminodiphenyl sulfone with an imidazole accelerator, which can control the curing rate, ensure complete curing, and avoid excessive internal stress.

[0020] A method for preparing an impact-resistant composite material for bicycles, as shown in the attached figure. Figure 1 As shown, it includes the following steps: Step 100, raw material pretreatment, carbon fiber, basalt fiber, polyethylene fiber are subjected to fiber plasma treatment, that is, argon atmosphere, power 300-500W, treatment time 15-25min, micro-nano pores are etched on the fiber surface to increase surface roughness and the number of active groups, thereby increasing the bonding area between epoxy resin and the above carbon fiber, basalt fiber, polyethylene fiber, and significantly improving interfacial bonding force. The bamboo charcoal fiber is dried at 120-150℃ for 4-6 hours, and the moisture content of the bamboo charcoal fiber is controlled to be ≤0.5% to avoid moisture affecting the curing of epoxy resin and interfacial bonding. Nano-silica is modified with silane coupling agent KH-550 to introduce organic groups on the surface of nanoparticles through chemical bonding and interaction, thus avoiding the problem of easy agglomeration in epoxy resin. The amount of silane coupling agent KH-550 is 3-5% of the mass of nano-silica, and the mixture is stirred at 60-80℃ for 2-3 hours.

[0021] Step 200, first mixing, the pretreated carbon fiber, basalt fiber, polyethylene fiber, bamboo charcoal fiber, nano silicon dioxide, titanium carbide, polyamide fiber are put into the ball mill mixer, and the dispersing agent is added to ensure that the fibers are not entangled, the rotating speed is 80-100 r / min, and the mixing time is 2-3 h, and a uniformly dispersed solid phase mixture is obtained; Step 300, second mixing, the epoxy resin is added to the reaction kettle, heated to 60-80℃ to melt, and the toughening agent is added, stirred at a rotating speed of 300-500 r / min for 30-60 min until completely dissolved, and then the solid phase mixture is added, transferred to a high-speed mixer, the rotating speed is adjusted to 180-220 r / min, the temperature is 70-90℃, and centrifugal mixing is carried out for 3-5 h to obtain a preliminary mixture; Step 400, third mixing, the preliminary mixture is cooled to 50-60℃, the curing agent is added, and stirring is carried out at a rotating speed of 100-120 r / min for 1-2 h to ensure that the curing agent is uniformly dispersed in the preliminary mixture, and a final mixture is obtained; Step 500, gradient curing forming treatment, the final mixture is injected into a mold preheated to 80-100℃, the mold pressure is controlled at 5-8 MPa, first heat preservation at 120-140℃ for 2-3 h, then heat up to 180-200℃ at a rate of 5-10℃ / min, heat preservation for 4-6 h, finally, heat down to 80-100℃ at a rate of 3-5℃ / min, heat preservation for 1-2 h, and demolding after natural cooling to room temperature, to obtain a composite material.

[0022] In this application, gradient temperature curing is adopted, that is, three gradients of low-temperature preheating, high-temperature curing and cooling, which reduces the internal stress of the final composite material, makes the resin matrix flow slowly through low temperature, fills the gap of the mold, ensures complete curing through high temperature, releases internal stress in the cooling stage, and improves the stability of the composite material.

[0023] In some preferred embodiments of the application, after the treatment of step 500, post-processing is also carried out, that is, the demolded composite material is surface polished by sandpaper to remove burrs and overflow, and then dried in a hot air drying oven at 80-100℃ for 2-3 h, and finally the finished product is obtained.

[0024] Example 1 An impact-resistant composite material for bicycles, comprising the following components by mass fraction: epoxy resin 60 parts, carbon fiber 35 parts, basalt fiber 15 parts, polyethylene fiber 10 parts, bamboo charcoal fiber 8 parts, nano silicon dioxide 5 parts, titanium carbide 4 parts, polyamide fiber 9 parts, curing agent 9 parts, dispersing agent 3 parts, and toughening agent 6 parts.

[0025] The basalt fiber has a single filament diameter of 10 μm and a tensile strength of 3800 MPa, and the nano-silica has a particle size of 80 nm. The toughening agent is a carboxyl-terminated nitrile butadiene rubber with a number-average molecular weight of 4000 and a carboxyl content of 0.8 mmol / g. The curing agent is prepared by compounding 4,4'-diaminodiphenyl sulfone with an imidazole accelerator.

[0026] A method for preparing an impact-resistant composite material for bicycles, as shown in the attached figure. Figure 1 As shown, it includes the following steps: Step 100, raw material pretreatment, carbon fiber, basalt fiber and polyethylene fiber are subjected to fiber plasma treatment, that is, argon atmosphere, power 400W, treatment time 25min. The bamboo charcoal fiber was dried at 150℃ for 6 hours. Nano-silica was modified with silane coupling agent KH-550, the amount of which was 3% of the mass of nano-silica, and stirred at 70°C for 2.5 h.

[0027] Step 200, first mixing: the pretreated carbon fiber, basalt fiber, polyethylene fiber, bamboo charcoal fiber, nano silica, titanium carbide and polyamide fiber are put into a ball mill mixer, a dispersant is added, the speed is 100 r / min, the mixing time is 3h, and a uniformly dispersed solid mixture is obtained. Step 300, second mixing: Add epoxy resin to the reactor, heat to 80°C to melt it, add toughening agent, stir at 400 r / min for 45 min until completely dissolved, then add solid mixture, transfer to high speed mixer, adjust speed to 220 r / min and temperature to 90°C, centrifuge and mix for 5 h to obtain initial mixture; Step 400, third mixing: cool the initial mixture to 60°C, add the curing agent, and stir at 120 r / min for 2 hours to ensure that the curing agent is evenly dispersed in the initial mixture to obtain the final mixture; Step 500: Gradient curing molding process. The final mixture is injected into a mold preheated to 100°C, with the mold pressure controlled at 7MPa. It is first held at 140°C for 3 hours, then heated to 200°C at a rate of 10°C / min and held for 6 hours. Finally, it is cooled to 100°C at a rate of 5°C / min and held for 2 hours. After naturally cooling to room temperature, it is demolded to obtain the composite material.

[0028] The final composite material was tested for performance. The tensile strength was 1756 MPa, the fracture toughness was 928 MPa, the transverse impact strength was 8.6 kJ / m², and there was no significant change in the 1000-h aging resistance test. It can be used for the preparation of bicycles.

[0029] Embodiment 2 An impact-resistant composite material for bicycles comprises, by mass fraction, the following components: epoxy resin 40 parts, carbon fiber 20 parts, basalt fiber 8 parts, polyethylene fiber 5 parts, bamboo charcoal fiber 3 parts, nano-silicon dioxide 2 parts, titanium carbide 1 part, polyamide fiber 4 parts, curing agent 4.5 parts, dispersant 1 part, toughening agent 2 parts.

[0030] The single filament diameter of the basalt fiber is 8 μm, and the tensile strength is 3500 MPa, the particle size of the nano-silicon dioxide is 50 nm, The toughening agent is carboxyl-terminated nitrile rubber with a number average molecular weight of 3000 and a carboxyl content of 0.5 mmol / g. The curing agent is prepared by compounding 4,4'-diamino diphenyl sulfone and an imidazole type accelerator.

[0031] A preparation method of an impact-resistant composite material for bicycles, as shown in the accompanying Figure 1 The method comprises the following steps: Step 100, raw material pretreatment, carbon fiber, basalt fiber and polyethylene fiber are subjected to fiber plasma treatment, that is, argon atmosphere is used, the power is 300 W, and the treatment time is 15 min; The bamboo charcoal fiber is subjected to drying treatment at 120℃ for 4h; The nano-silicon dioxide is subjected to modification treatment by silane coupling agent KH-550, the amount of the silane coupling agent KH-550 is 3% of the mass of the nano-silicon dioxide, and stirring is carried out at 60℃ for 2h.

[0032] Step 200, first mixing, the pretreated carbon fiber, basalt fiber, polyethylene fiber, bamboo charcoal fiber, nano-silicon dioxide, titanium carbide and polyamide fiber are put into a ball mill mixer, the dispersant is added, the rotating speed is 80 r / min, and the mixing time is 2h, so that a uniformly dispersed solid phase mixture is obtained; Step 300, second mixing, the epoxy resin is added into a reaction kettle, heated to 60℃ to melt, the toughening agent is added, stirring is carried out at a rotating speed of 300 r / min for 30 min until complete dissolution, then the solid phase mixture is added, transferred to a high-speed mixer, the rotating speed is adjusted to 180 r / min, the temperature is 70℃, and centrifugal mixing is carried out for 3h, so that a preliminary mixture is obtained; Step 400, third mixing, the preliminary mixture is cooled to 50℃, the curing agent is added, stirring is carried out at a rotating speed of 100 r / min for 1h, so that the curing agent is uniformly dispersed in the preliminary mixture, and a final mixture is obtained; Step 500, gradient curing forming process, the final mixture is injected into a mold preheated to 80℃, the mold pressure is controlled at 5MPa, first heat preservation at 120℃ for 2h, then increase to 180℃ at a heating rate of 5℃ / min, heat preservation for 4h, finally decrease to 80℃ at a cooling rate of 3℃ / min, heat preservation for 1h, demoulding after natural cooling to room temperature, to obtain the composite material.

[0033] The final generated composite material is tested for performance, the tensile strength is 1512MPa, the fracture toughness is 795MPa, the transverse impact strength is 6.8kJ / m², and there is no obvious change in 1000h aging resistance experiment, which can be used for the preparation of bicycles.

[0034] Example 3 An impact-resistant composite material for bicycles, by mass fraction, comprising the following components: epoxy resin 48 parts, carbon fiber 28 parts, basalt fiber 12 parts, polyethylene fiber 8 parts, bamboo charcoal fiber 6 parts, nano silicon dioxide 3.5 parts, titanium carbide 2.5 parts, polyamide fiber 6 parts, curing agent 6.7 parts, dispersing agent 2 parts, toughening agent 4 parts.

[0035] The single filament diameter of the basalt fiber is 11μm, the tensile strength is 3600MPa, the particle size of the nano silicon dioxide is 70 nm, The toughening agent is carboxyl-terminated nitrile rubber, the number average molecular weight is 4500, and the carboxyl content is 0.9mmol / g. The curing agent is prepared by compounding 4,4'-diamino diphenyl sulfone and imidazole type accelerant.

[0036] A preparation method of an impact-resistant composite material for bicycles, as shown in the accompanying Figure 1 The preparation method comprises the following steps: Step 100, raw material pretreatment, the carbon fiber, basalt fiber and polyethylene fiber are subjected to fiber plasma treatment, that is, argon atmosphere is adopted, the power is 400W, and the treatment time is 20min; The bamboo charcoal fiber is subjected to drying treatment at 130℃ for 5h; The nano silicon dioxide is subjected to modification treatment by silane coupling agent KH-550, the amount of the silane coupling agent KH-550 is 4% of the mass of the nano silicon dioxide, and stirring is carried out at 70℃ for 2.5h.

[0037] Step 200, first mixing, the pretreated carbon fiber, basalt fiber, polyethylene fiber, bamboo charcoal fiber, nano silicon dioxide, titanium carbide and polyamide fiber are put into a ball mill mixer, the dispersing agent is added, the rotating speed is 90r / min, and the mixing time is 2.5h, to obtain a uniformly dispersed solid phase mixture; Step 300, second mixing, epoxy resin is added into the reaction kettle, heated to 70℃ to melt, and the toughening agent is added, stirred at a speed of 400r / min for 45min until completely dissolved, then the solid phase mixture is added, transferred to a high-speed mixer, the speed is adjusted to 200r / min, the temperature is 80℃, and centrifugal mixing is carried out for 4h to obtain the primary mixture; Step 400, third mixing, the primary mixture is cooled to 55℃, the curing agent is added, and stirred at a speed of 110r / min for 1.5h to ensure uniform dispersion of the curing agent in the primary mixture to obtain the final mixture; Step 500, gradient curing forming treatment, the final mixture is injected into a mold preheated to 90℃, the mold pressure is controlled at 7MPa, first kept at 130℃ for 2.5h, then raised to 190℃ at a rate of 7℃ / min, kept for 5h, finally reduced to 90℃ at a rate of 4℃ / min, kept for 1.5h, and demolded after natural cooling to room temperature to obtain the composite material.

[0038] The final composite material is tested for performance, the tensile strength is 1635MPa, the fracture toughness is 862MPa, the transverse impact strength is 7.5kJ / m², and there is no obvious change in 1000h aging resistance test, which can be used for the preparation of bicycles.

[0039] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An impact-resistant composite material for bicycles, characterized in that it comprises, by mass fraction: 40-60 parts of epoxy resin, 20-35 parts of carbon fiber, 8-15 parts of basalt fiber, 5-10 parts of polyethylene fiber, 3-8 parts of bamboo charcoal fiber, 2-5 parts of nano-silicon dioxide, 1-4 parts of titanium carbide, 4-9 parts of polyamide fiber, 4-10 parts of curing agent, 1-3 parts of dispersing agent, and 2-6 parts of toughening agent.

2. The impact-resistant composite material for bicycles according to claim 1, characterized in that: the basalt fiber has a single-filament diameter of 8-12 μm and a tensile strength of ≥3500 MPa, and the nano-silicon dioxide has a particle size of 50-100 nm.

3. A method for preparing the impact-resistant composite material for bicycles according to any one of claims 1-2, characterized in that it comprises the following steps: Step 100, raw material pretreatment, wherein the carbon fiber, basalt fiber and polyethylene fiber are subjected to fiber plasma treatment, the bamboo charcoal fiber is subjected to drying treatment, and the nano-silicon dioxide is subjected to modification treatment by silane coupling agent KH-550; Step 200, first mixing, wherein the pretreated carbon fiber, basalt fiber, polyethylene fiber, bamboo charcoal fiber, nano-silicon dioxide, titanium carbide and polyamide fiber are put into a ball mill mixer, and a dispersing agent is added to obtain a solid-phase mixture; Step 300, second mixing, wherein the epoxy resin is added to a reaction kettle, heated to melt, and then the toughening agent is added and stirred until completely dissolved, followed by adding the solid-phase mixture and transferring to a high-speed mixer to obtain a preliminary mixture; Step 400, third mixing, wherein the preliminary mixture is cooled, and the curing agent is added and stirred to obtain a final mixture; and Step 500, gradient curing and molding treatment, wherein the final mixture is injected into a preheated mold, first kept warm, then heated, and finally cooled, naturally cooled to room temperature, and then demolded to obtain the composite material.

4. The method for preparing the impact-resistant composite material for bicycles according to claim 3, characterized in that, in Step 100, during the fiber plasma treatment, an argon atmosphere is used, the power is 300-500 W, and the treatment time is 15-25 min to etch micro-nano pores on the fiber surface.

5. The method for preparing the impact-resistant composite material for bicycles according to claim 3, characterized in that, in Step 100, during the drying treatment, the drying is performed at 120-150 °C for 4-6 h; and the amount of the silane coupling agent KH-550 used is 3-5% of the mass of the nano-silicon dioxide, and the modification treatment is performed by stirring at 60-80 °C for 2-3 h.

6. The method for preparing the impact-resistant composite material for bicycles according to claim 3, characterized in that, in Step 200, during the first mixing treatment, the rotation speed is 80-100 r / min, and the mixing time is 2-3 h.

7. The method for preparing the impact-resistant composite material for bicycles according to claim 3, characterized in that: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In step 300, the second mixing process, first heated to 60-80℃ to melt, after adding toughening agent, stirring at 300-500r / min for 30-60min to completely dissolved, then add solid phase mixture, transfer to high speed mixer, adjust the speed to 180-220r / min, temperature 70-90℃, centrifugal mixing 3-5h, get the initial mixture.

8. The preparation method of the shock-resistant composite material for bicycles according to claim 3, characterized in that: In step 400, the third mixing process, the initial mixture is cooled to 50-60℃, add curing agent, stirring at 100-120r / min for 1-2h, ensure the curing agent evenly dispersed in the initial mixture, get the final mixture.

9. The preparation method of the shock-resistant composite material for bicycles according to claim 3, characterized in that: In step 500, the gradient curing forming process, first inject the final mixture into the mold preheated to 80-100℃, the mold pressure control in 5-8MPa, first at 120-140℃ for 2-3h, then with the heating rate of 5-10℃ / min to 180-200℃, 4-6h, finally with the cooling rate of 3-5℃ / min to 80-100℃, 1-2h, natural cooling to room temperature, demoulding, get the composite material.

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