Preparation method of copper-free and steel-free carbon fiber composite material friction plate applied to electric bicycle

Abstract

The invention relates to a preparation method of a copper-free and steel-free carbon fiber composite material friction plate applied to an electric bicycle. The preparation method comprises the following steps: adding graphite and polyether-ether-ketone powder into impregnation liquid, and uniformly mixing; putting the pretreated carbon fiber cloth into the steeping liquor for ultrasonic steeping, drying, putting into the steeping liquor for repeated steeping, and drying; and putting the dried carbon fiber cloth into a mold, and carrying out compression molding to obtain the copper-free and steel-free carbon fiber composite material friction plate applied to the electric bicycle. The impregnation liquid is prepared from phenol, boric acid / nickel complex modified diphenol, formaldehyde, 1, 8-dialdehyde anthracene, oxalic acid, zinc acetate, cashew nut shell oil, a curing agent and ethanol. The friction coefficient of the prepared carbon fiber composite material friction plate is 0.31, the wear rate is 0.33 * 10 <-6 > g / N.m, and the carbon fiber composite material friction plate has excellent friction resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of friction plate preparation, and in particular to a preparation method of a copper-free and steel-free carbon fiber composite friction plate applied to electric bicycles. Background Art

[0002] In the braking system of an electric bicycle, the most important component is the brake pad, and the braking performance completely depends on the quality of the brake pad. A brake pad with excellent performance can provide a high friction coefficient and a low wear rate. Selecting a suitable brake pad material is crucial for safety. Resin-based carbon fiber composite materials have a stable friction coefficient, a low wear rate, and can resist high temperatures, making them ideal brake pad materials.

[0003] Chinese Patent CN113636853B: provides a preparation method of a carbon fiber composite brake pad, including the following steps: S1, mixing phenolic resin, polyethylene glycol, and acetone to prepare a coating impregnation solution; mixing graphite flakes, short fibers, nano-silicon powder, fumed silica, and phenolic resin solution, and then ball-milling and dispersing them to form an impregnation mixture; S2, oxidizing the surface of carbon fiber fabric, and then coating the carbon fiber fabric with the coating impregnation solution; constructing the brake pad body according to the required shape and then performing carbonization treatment; S3, using the method of air extraction impregnation to impregnate the brake pad body with the impregnation mixture, heating and shaping, and finally performing graphitization in a nitrogen atmosphere to obtain the carbon fiber composite brake pad.

[0004] Chinese Patent CN108662050B: discloses a carbon fiber brake pad material with a porous structure and its preparation method. Using carbon fiber-carbon nanotube (CF-CNTs) composite fibers and fillers as the matrix, and cashew oil-modified phenolic resin as the binder, a porous structure is obtained by adding a pore-forming agent, and a carbon fiber brake pad material is prepared by using a dry hot pressing molding technique.

[0005] Chinese Patent CN117466625A: relates to the technical field of brake discs, specifically regarding a composite process of a carbon-ceramic brake disc with composite carbon fibers; the carbon-ceramic brake disc with composite carbon fibers prepared by the organometallic titanium of diboron group modified ceramic fibers in the present invention promotes the interfacial reaction between carbon fibers and the ceramic matrix; in addition, organometallic titanium can also form a dense titanium carbide protective layer on the surface of carbon fibers by methods such as chemical vapor deposition, improving the antioxidant performance of carbon fibers; mixing the prepared composite carbon fibers with ceramic fibers, and then performing hot pressing molding at a certain temperature and pressure to obtain a carbon-ceramic brake disc.

[0006] The friction plates prepared by the above patents and the prior art have a high wear rate and unsatisfactory friction resistance performance. Summary of the Invention

[0007] To solve the above problems, the present invention provides a method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles, and the operation steps are as follows:

[0008] S1: Add 5-15 parts of graphite and 1-5 parts of polyether ether ketone powder to the impregnating solution, and mix evenly;

[0009] S2: Put the pretreated carbon fiber cloth into the impregnating solution in S1, perform ultrasonic impregnation, then dry it, and then put it into the impregnating solution again for repeated impregnation and drying;

[0010] S3: Put the dried carbon fiber cloth into a mold and press it into shape to obtain a copper-free and steel-free carbon fiber composite friction plate for electric bicycles.

[0011] The impregnation time in S2 is 10-20 min.

[0012] The pressure for the press molding is 3-6 Mpa, the temperature is 150-170 °C, and the time is 10-30 min.

[0013] The preparation method of the impregnating solution is as follows:

[0014] H1: Weigh 22-34 parts of phenol, 1-4 parts of biphenol modified with boric acid / nickel complex, 14-18 parts of formaldehyde, 0.02-0.2 parts of 1,8-dialdehyde anthracene CAS: 34824-75-4, add them to a reaction kettle, stir and mix, then continue to add 1-5 parts of oxalic acid, 1-3 parts of zinc acetate, 1-3 parts of cashew shell oil, adjust the pH value to 2-3, and raise the temperature for reaction;

[0015] H2: After the reaction is completed, perform vacuum distillation to obtain phenolic resin;

[0016] H3: Add 1-5 parts of curing agent to the phenolic resin, mix evenly, and then add 80-100 parts of ethanol to obtain the impregnating solution.

[0017] The preparation method of the biphenol modified with boric acid / nickel complex is as follows:

[0018] Weigh 10-20 parts of 2,2-diallyl-4,4'-biphenol CAS: 6942-01-4, 0.3-2 parts of 2-amino-5-fluorophenylboric acid / nickel complex, 2-5 parts of triethylamine, 100-120 parts of toluene in a reaction kettle, stir and react at 70-80 °C for 100-120 minutes, distill off toluene to obtain the biphenol modified with boric acid / nickel complex.

[0019] The preparation method of the 2-amino-5-fluorophenylboric acid / nickel complex is as follows:

[0020] By weight parts, 7 - 15 parts of 2 - amino - 5 - fluorophenylboronic acid, 6 - 10 parts of nickel nitrate, and 100 - 150 parts of toluene are mixed, and reacted at 60 - 70 °C for 150 - 200 minutes. Then, toluene is removed by distillation to obtain 2 - amino - 5 - fluorophenylboronic acid / nickel complex.

[0021] The reaction temperature of H1 is 80 - 100 °C and the time is 3 - 5 h.

[0022] The curing agent is hexamethylenetetramine.

[0023] The pretreatment steps of the carbon fiber cloth are as follows:

[0024] A1: The carbon fiber cloth is put into acetone and soaked for 20 - 25 h, then ultrasonically cleaned with distilled water for 20 - 30 min and dried.

[0025] A2: The dried carbon fiber cloth is put into concentrated nitric acid and soaked for 120 - 180 min, then washed with distilled water until neutral and dried.

[0026] A3: The carbon fiber cloth treated with concentrated nitric acid is put into a silane coupling agent solution and soaked for 80 - 120 min, then dried.

[0027] The silane coupling agent is amino - silane, epoxy - silane, mercapto - silane, methacryloxy - silane, vinyl - silane, ureido - silane, and isocyanate - silane.

[0028] Reaction mechanism

[0029] 1. Catalytic action of boric acid / nickel complex:

[0030] Boric acid or its derivatives (such as borate esters) and nickel complexes act as catalysts together to promote the polycondensation reaction; the boric acid / nickel complex accelerates the condensation reaction between formaldehyde and bisphenol, 1,8 - dialdehyde anthracene, and phenol by forming reactive intermediates or reducing the reaction activation energy.

[0031] 2. Polycondensation reaction process:

[0032] Under alkaline conditions (usually using sodium hydroxide or ammonia water as catalysts), formaldehyde undergoes a condensation reaction with bisphenol, 1,8 - dialdehyde anthracene, and phenol to form intermediates containing multiple hydroxymethyl groups; these intermediates further cross - link to form a phenolic resin with a three - dimensional network structure; during this process, the boric acid / nickel complex can participate in forming specific chemical bonds or stabilizing reaction intermediates, thus affecting the structure and properties of the final product.

[0033] Technical effects

[0034] A preparation method of a copper-free and steel-free carbon fiber composite friction plate for electric bicycles. Compared with the prior art, the present invention has the following remarkable effects:

[0035] 1. Improve heat resistance:

[0036] The introduction of boric acid significantly improves the heat resistance of phenolic resin; research shows that the char residue rate of boron-containing phenolic resin at high temperature is much higher than that of traditional phenolic resin, which helps the friction plate maintain structural stability and performance in high-temperature environments.

[0037] 2. Enhance mechanical properties:

[0038] As a binder, phenolic resin can effectively transfer load and disperse stress, thereby improving the overall mechanical properties of the friction plate.

[0039] 3. Improve friction and wear performance:

[0040] Phenolic resin has good self-lubricity and wear resistance, and can form a stable friction film during the friction process, reducing wear and noise; it can further improve the wear resistance and anti-seizure properties of the friction plate and extend its service life. Specific embodiments

[0041] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description in combination with examples and comparative examples:

[0042] Friction coefficient and wear rate test: The composite material was tested using a multi-functional vertical friction and wear testing machine.

[0043] Example 1

[0044] A preparation method of a copper-free and steel-free carbon fiber composite friction plate for electric bicycles, the operation steps of which are as follows:

[0045] S1: Add 5 g of graphite and 1 g of polyether ether ketone powder to the impregnating solution and mix evenly;

[0046] S2: Put the pretreated carbon fiber cloth into the impregnating solution in S1, perform ultrasonic impregnation, dry it, then put it into the impregnating solution again for repeated impregnation and drying;

[0047] S3: Put the dried carbon fiber cloth into a mold and perform molding under pressure to obtain a copper-free and steel-free carbon fiber composite friction plate for electric bicycles.

[0048] The impregnation time in S2 is 10 min.

[0049] The pressure for molding under pressure is 3 Mpa, the temperature is 150 °C, and the time is 10 min.

[0050] The preparation method of the impregnating solution is as follows:

[0051] H1: Weigh 22 g of phenol, 1 g of biphenol modified with boric acid / nickel complex, 14 g of formaldehyde, and 0.02 g of 1,8-dialdehyde anthracene CAS: 34824-75-4. Add them to a reaction kettle. After stirring and mixing, continue to add 1 g of oxalic acid, 1 g of zinc acetate, and 1 g of cashew shell oil. Adjust the pH value to 2 and raise the temperature for reaction;

[0052] H2: After the reaction is completed, perform vacuum distillation to obtain phenolic resin;

[0053] H3: Add 1 g of curing agent to the phenolic resin, mix evenly, and then add 80 g of ethanol to obtain the impregnating solution.

[0054] The preparation method of the biphenol modified with boric acid / nickel complex is as follows:

[0055] Add 10 g of 2,2-diallyl-4,4'-biphenol CAS: 6942-01-4, 0.3 g of 2-amino-5-fluorobenzeneboronic acid / nickel complex, 2 g of triethylamine, and 100 g of toluene to a reaction kettle. Stir and react at 70 °C for 100 minutes. Distill off the toluene to obtain the biphenol modified with boric acid / nickel complex.

[0056] The preparation method of the 2-amino-5-fluorobenzeneboronic acid / nickel complex is as follows:

[0057] Mix 7 g of 2-amino-5-fluorobenzeneboronic acid, 6 g of nickel nitrate, and 100 g of toluene, react at 60 °C for 150 minutes, and distill off the toluene to obtain the 2-amino-5-fluorobenzeneboronic acid / nickel complex.

[0058] The reaction temperature of H1 is 80 °C and the time is 3 h.

[0059] The curing agent is hexamethylenetetramine.

[0060] The pretreatment steps of the carbon fiber cloth are as follows:

[0061] A1: Immerse the carbon fiber cloth in acetone for 20 h, then ultrasonically clean it with distilled water for 20 min, and dry it;

[0062] A2: Immerse the dried carbon fiber cloth in concentrated nitric acid for 120 min, then wash it with distilled water until neutral, and dry it;

[0063] A3: Immerse the carbon fiber cloth treated with concentrated nitric acid in a silane coupling agent solution for 80 min, and then dry it.

[0064] The silane coupling agent is amino silane.

[0065] Example 2

[0066] A preparation method of a copper-free and steel-free carbon fiber composite friction plate for electric bicycles, and its operation steps are as follows:

[0067] S1: Add 8 g of graphite and 2 g of polyether ether ketone powder to the impregnating solution and mix evenly;

[0068] S2: Put the pretreated carbon fiber cloth into the impregnating solution in S1, carry out ultrasonic impregnation, then dry it, and then put it into the impregnating solution again for repeated impregnation and drying;

[0069] S3: Put the dried carbon fiber cloth into a mold and carry out molding under pressure to obtain a copper-free and steel-free carbon fiber composite friction plate for electric bicycles.

[0070] The impregnation time in S2 is 15 min.

[0071] The pressure for molding under pressure is 4 Mpa, the temperature is 155 °C, and the time is 15 min.

[0072] The preparation method of the impregnating solution is as follows:

[0073] H1: Weigh 28 g of phenol, 2 g of biphenol modified with boric acid / nickel complex, 15 g of formaldehyde, and 0.1 g of 1,8-dialdehyde anthracene CAS: 34824-75-4, add them to the reaction kettle, stir and mix, then continue to add 2 g of oxalic acid, 2 g of zinc acetate, and 2 g of cashew nut shell oil, adjust the pH value to 22, and raise the temperature for reaction;

[0074] H2: After the reaction is completed, carry out vacuum distillation to obtain phenolic resin;

[0075] H3: Add 2 g of curing agent to the phenolic resin, mix evenly, and then add 85 g of ethanol to obtain the impregnating solution.

[0076] The preparation method of the biphenol modified with boric acid / nickel complex is as follows:

[0077] Add 13 g of 2,2-diallyl-4,4'-biphenol CAS: 6942-01-4, 1 g of 2-amino-5-fluorobenzeneboronic acid / nickel complex, 3 g of triethylamine, and 105 g of toluene to the reaction kettle, stir and react at 75 °C for 105 minutes, distill off toluene to obtain biphenol modified with boric acid / nickel complex.

[0078] The preparation method of the 2-amino-5-fluorobenzeneboronic acid / nickel complex is as follows:

[0079] Mix 9 g of 2-amino-5-fluorobenzeneboronic acid, 7 g of nickel nitrate, and 110 toluene, react at 65 °C for 160 minutes, distill off toluene to obtain 2-amino-5-fluorobenzeneboronic acid / nickel complex.

[0080] The reaction temperature of the described H1 is 85 °C and the time is 4 h.

[0081] The described curing agent is hexamethylenetetramine.

[0082] The pretreatment steps of the described carbon fiber cloth are as follows:

[0083] A1: Immerse the carbon fiber cloth in acetone for 22 h, then ultrasonically clean it with distilled water for 25 min and dry it.

[0084] A2: Immerse the dried carbon fiber cloth in concentrated nitric acid for 140 min, then wash it with distilled water until neutral and dry it.

[0085] A3: Immerse the carbon fiber cloth treated with concentrated nitric acid in a silane coupling agent solution for 90 min and then dry it.

[0086] The described silane coupling agent is epoxy-based silane.

[0087] Example 3

[0088] A preparation method of a copper-free and steel-free carbon fiber composite friction plate for electric bicycles, the operation steps are as follows:

[0089] S1: Add 13 g of graphite and 4 g of polyetheretherketone powder to the impregnating solution and mix evenly.

[0090] S2: Put the pretreated carbon fiber cloth into the impregnating solution in S1 for ultrasonic impregnation, then dry it, and then put it into the impregnating solution again for repeated impregnation and drying.

[0091] S3: Put the dried carbon fiber cloth into a mold and press it into shape to obtain a copper-free and steel-free carbon fiber composite friction plate for electric bicycles.

[0092] The impregnation time of the described S2 is 15 min.

[0093] The pressure of the described press molding is 5 Mpa, the temperature is 165 °C, and the time is 25 min.

[0094] The preparation method of the described impregnating solution is as follows:

[0095] H1: Weigh 32 g of phenol, 3 g of biphenol modified with boric acid / nickel complex, 17 g of formaldehyde, 0.15 g of 1,8-dialdehyde anthracene CAS: 34824-75-4, add them to a reaction kettle, stir and mix, then continue to add 4 g of oxalic acid, 2 g of zinc acetate, 2 g of cashew shell oil, adjust the PH value to 3, and raise the temperature for reaction.

[0096] H2: After the reaction is completed, perform vacuum distillation to obtain phenolic resin.

[0097] H3: Add 4 g of curing agent to the phenolic resin, mix evenly, and then add 95 g of ethanol to obtain an impregnating solution.

[0098] The preparation method of the boric acid / nickel complex modified biphenol is as follows:

[0099] Add 18 g of 2,2-diallyl-4,4'-biphenol CAS: 6942-01-4, 1.5 g of 2-amino-5-fluorophenylboric acid / nickel complex, 4 g of triethylamine, and 115 g of toluene to the reaction kettle, stir and react at 75 °C for 115 minutes, and distill off toluene to obtain the boric acid / nickel complex modified biphenol.

[0100] The preparation method of the 2-amino-5-fluorophenylboric acid / nickel complex is as follows:

[0101] Mix 13 g of 2-amino-5-fluorophenylboric acid, 9 g of nickel nitrate, and 140 toluene, react at 65 °C for 180 minutes, and distill off toluene to obtain the 2-amino-5-fluorophenylboric acid / nickel complex.

[0102] The reaction temperature of the described H1 is 95 °C and the time is 4 h.

[0103] The curing agent is hexamethylenetetramine.

[0104] The pretreatment steps of the carbon fiber cloth are as follows:

[0105] A1: Immerse the carbon fiber cloth in acetone for 24 h, then ultrasonically clean it with distilled water for 25 min, and dry it.

[0106] A2: Immerse the dried carbon fiber cloth in concentrated nitric acid for 160 min, then wash it with distilled water until neutral, and dry it.

[0107] A3: Immerse the carbon fiber cloth treated with concentrated nitric acid in the silane coupling agent solution for 110 min, and then dry it.

[0108] The silane coupling agent is sulfhydryl silane.

[0109] Example 4

[0110] A preparation method of a copper-free and steel-free carbon fiber composite friction plate for electric bicycles, the operation steps are as follows:

[0111] S1: Add 15 g of graphite and 5 g of polyetheretherketone powder to the impregnating solution and mix evenly.

[0112] S2: Put the pretreated carbon fiber cloth into the impregnating solution in S1 for ultrasonic impregnation, then dry it, and then put it into the impregnating solution for repeated impregnation and drying.

[0113] S3: Put the dried carbon fiber cloth into a mold and form it by molding to obtain a copper-free and steel-free carbon fiber composite friction plate for electric bicycles.

[0114] The impregnation time in S2 is 20 min.

[0115] The pressure for the molding is 6 Mpa, the temperature is 170 °C, and the time is 30 min.

[0116] The preparation method of the impregnating solution is as follows:

[0117] H1: Weigh 34 g of phenol, 4 g of biphenol modified with boric acid / nickel complex, 18 g of formaldehyde, and 0.2 g of 1,8-dialdehyde anthracene CAS: 34824-75-4, add them to a reaction kettle, after stirring and mixing, continue to add 5 g of oxalic acid, 3 g of zinc acetate, and 3 g of cashew shell oil, adjust the pH value to 3, and raise the temperature for reaction;

[0118] H2: After the reaction ends, perform vacuum distillation to obtain phenolic resin;

[0119] H3: Add 5 g of curing agent to the phenolic resin, mix evenly, and then add 100 g of ethanol to obtain the impregnating solution.

[0120] The preparation method of the biphenol modified with boric acid / nickel complex is as follows:

[0121] Add 20 g of 2,2-diallyl-4,4'-biphenol CAS: 6942-01-4, 2 g of 2-amino-5-fluorophenylboric acid / nickel complex, 5 g of triethylamine, and 120 g of toluene to a reaction kettle, stir and react at 80 °C for 120 minutes, distill off toluene to obtain the biphenol modified with boric acid / nickel complex.

[0122] The preparation method of the 2-amino-5-fluorophenylboric acid / nickel complex is as follows:

[0123] Mix 15 g of 2-amino-5-fluorophenylboric acid, 10 g of nickel nitrate, and 150 toluene, react at 70 °C for 200 minutes, distill off toluene to obtain the 2-amino-5-fluorophenylboric acid / nickel complex.

[0124] The reaction temperature in H1 is 100 °C and the time is 5 h.

[0125] The curing agent is hexamethylenetetramine.

[0126] The pretreatment steps of the carbon fiber cloth are as follows:

[0127] A1: Put the carbon fiber cloth into acetone and soak it for 25 h, then ultrasonically clean it with distilled water for 30 min and dry it.

[0128] A2: After the dried carbon fiber cloth is immersed in concentrated nitric acid for 180 min, it is washed with distilled water until neutral and then dried.

[0129] A3: After the carbon fiber cloth treated with concentrated nitric acid is immersed in a silane coupling agent solution for 120 min, it is dried.

[0130] The silane coupling agent described is isocyanate group silane.

[0131] Comparative Example 1

[0132] Do not add the biphenol modified with boric acid / nickel complex, and the others are the same as in Example 1.

[0133] Comparative Example 2

[0134] Do not add 2-amino-5-fluorophenylboronic acid / nickel complex, and the others are the same as in Example 1.

[0135] Comparative Example 3

[0136] Do not add 2,2-diallyl-4,4'-biphenol, and the others are the same as in Example 1.

[0137] Coefficient of friction <![CDATA[Wear rate / ×10 -6 g / N·m]]> Example 1 0.26 0.45 Example 2 0.28 0.41 Example 3 0.30 0.37 Example 4 0.31 0.33 Comparative Example 1 0.16 0.85 Comparative Example 2 0.19 0.69 Comparative Example 3 0.20 0.58

[0138] Through the data analysis of the above examples and comparative examples, the carbon fiber composite friction plate prepared by the present invention has good wear resistance.

[0139] The above is only the preferred embodiments of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed as above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles, the operating steps of which are as follows: S1: Add 5-15 parts of graphite and 1-5 parts of polyetheretherketone powder to the impregnation solution and mix well; S2: placing the pretreated carbon fiber cloth into the impregnation solution of S1, ultrasonically impregnating it, drying it, and then placing it into the impregnation solution again, and repeatedly impregnating it, and drying it; S3: placing the dried carbon fiber cloth into a mold and performing compression molding to obtain a copper-free and steel-free carbon fiber composite friction plate for electric bicycles.

2. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 1, characterized in that: The immersion time of S2 is 10-20 minutes.

3. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 1, characterized in that: The compression molding process has a pressure of 3-6 MPa, a temperature of 150-170° C., and a time of 10-30 min.

4. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 1, characterized in that: The preparation method of the impregnation solution is: H1: Weigh 22-34 parts of phenol, 1-4 parts of biphenol modified with boric acid / nickel complex, 14-18 parts of formaldehyde, and 0.02-0.2 parts of 1,8-dialdehyde anthracene by weight, add them to a reactor, stir and mix, then continue to add 1-5 parts of oxalic acid, 1-3 parts of zinc acetate, and 1-3 parts of cashew nut shell oil, adjust the pH value to 2-3, and heat the reaction; H2: After the reaction is completed, phenolic resin is obtained by vacuum distillation; H3: Add 1-5 parts of curing agent to phenolic resin, mix well, and then add 80-100 parts of ethanol to obtain an impregnation solution.

5. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 4, characterized in that: The preparation method of the biphenol modified by the boric acid / nickel complex is as follows: In parts by weight, 10-20 parts of 2,2-diallyl-4,4'-biphenol, 0.3-2 parts of 2-amino-5-fluorophenylboric acid / nickel complex, 2-5 parts of triethylamine and 100-120 parts of toluene are added into a reaction kettle, stirred and reacted at 70-80° C. for 100-120 minutes, and toluene is removed by distillation to obtain biphenol modified with the boric acid / nickel complex.

6. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 5, characterized in that: The preparation method of the 2-amino-5-fluorophenylboronic acid / nickel complex is: According to weight, 7-15 parts of 2-amino-5-fluorophenylboric acid, 6-10 parts of nickel nitrate and 100-150 parts of toluene are mixed, reacted at 60-70° C. for 150-200 minutes, and toluene is removed by distillation to obtain a 2-amino-5-fluorophenylboric acid / nickel complex.

7. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 4, characterized in that: The reaction temperature of H1 is 80-100°C and the reaction time is 3-5h.

8. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 4, characterized in that: The curing agent is hexamethylenetetramine.

9. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 1, characterized in that: The pretreatment steps of the carbon fiber cloth are: A1: Soak the carbon fiber cloth in acetone for 20-25 hours, then ultrasonically clean it with distilled water for 20-30 minutes and dry it; A2: Soak the dried carbon fiber cloth in concentrated nitric acid for 120-180 minutes, wash with distilled water until neutral, and dry; A3: Soak the carbon fiber cloth treated with concentrated nitric acid in a silane coupling agent solution for 80-120 minutes and then dry it.

10. The method for preparing a copper-free and steel-free carbon fiber composite friction plate for electric bicycles according to claim 1, characterized in that: The silane coupling agent is aminosilane, epoxysilane, thiosilane, methacryloxysilane, vinylsilane, ureasilane and isocyanatesilane.