Preparation method of high-carbon / high-alloy composite brake disc for racing car

Abstract

The invention discloses a preparation method of a high-carbon / high-alloy composite material brake disc for a racing car, and belongs to the technical field of brake disc manufacturing. The preparation method of the brake disc comprises the following steps: (1) weighing the following components in parts by weight: 25-30 parts of phenolic resin, 10-15 parts of modified benzoxazine, 8-10 parts of low-carbon steel crushed fibers, 4-6 parts of reduced iron powder, 8-10 parts of brass fibers, 5-8 parts of para-aramid pulp and 8-10 parts of crystalline flake graphite; (2) adding the materials into a mixer, and uniformly mixing to obtain a mixture; (3) preheating a mold, smearing a release agent on the inner wall of the mold, pouring the mixture, and performing hot compression molding; and (4) carrying out heat treatment on the mold filled with the sample, and demolding. The prepared high-carbon / high-alloy composite material brake disc for the racing car has excellent shear strength and impact strength, good friction coefficient and low wear rate.

Description

Technical Field

[0001] The present invention relates to the technical field of brake disc manufacturing, and in particular to a method for preparing a high-carbon / high-alloy composite brake disc for racing cars. Background Art

[0002] Racing car brake discs must maintain high performance under high-speed driving and frequent braking conditions, placing extremely high demands on their materials. Brake discs must possess high wear resistance, high thermal stability, good shear strength, and sufficient impact strength to ensure they maintain excellent braking performance even in high-temperature and high-stress environments, reducing stopping distances and improving the safety and handling of the car. Traditional brake disc materials, such as cast iron and steel, while possessing sufficient strength and wear resistance, are susceptible to thermal fatigue and thermal cracking at high temperatures, resulting in reduced braking performance. Furthermore, the high density of cast iron and steel increases the vehicle's unsprung mass, hindering the car's lightweight design. Brake discs also suffer from issues such as unstable friction coefficients and poor shear strength, impacting the safety and handling of the car.

[0003] Chinese invention patent publication number CN106966751A discloses a high-performance, low-cost C / C-SiC composite brake disc, its preparation method, and application. The preparation method comprises: carbonizing a brake disc preform, densifying the carbonized disc preform using chemical vapor infiltration, heat treating it in an inert atmosphere, machining it, treating it using melt siliconization, and then treating it using chemical vapor infiltration or precursor impregnation and pyrolysis. The resulting product is then machined to the final design dimensions, resulting in the finished composite brake disc. The C / C-SiC composite brake disc and its preparation method provided by this invention can reduce production costs and improve the disc's thermal conductivity and friction and wear performance, but its shear strength is relatively poor. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a high-carbon / high-alloy composite brake disc for racing cars.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions: A method for preparing a high-carbon / high-alloy composite brake disc for racing cars comprises the following steps: (1) Weigh by weight: 25-30 parts of phenolic resin, 10-15 parts of modified benzoxazine, 8-10 parts of low carbon steel crushed fiber, 4-6 parts of reduced iron powder, 8-10 parts of brass fiber, 5-8 parts of para-aramid pulp, and 8-10 parts of flake graphite. (2) Add the above materials into the mixer and mix them evenly to obtain a mixture. (3) Preheat the mold, apply release agent on the inner wall of the mold, pour in the mixture, and hot mold forming. (4) Heat-treating and demoulding the mold containing the sample to obtain the product; The preparation method of the modified benzoxazine comprises the following steps: firstly, 4-aminophenylboronic acid reacts with 1-thioglycerol to generate intermediate 1; then, intermediate 1 reacts with tetramethyltetravinylcyclotetrasiloxane to generate intermediate 2; and finally, intermediate 2 reacts with p-trifluoromethylphenol under the action of paraformaldehyde to obtain the modified benzoxazine.

[0006] The modified benzoxazine is prepared by the following method: S1: Tetrahydrofuran and 4-aminophenylboronic acid were stirred and mixed, 1-thioglycerol was added, and the mixture was reacted at 50-60°C for 20-24 hours to generate intermediate 1. The reaction equation is shown below: .

[0007] S2: Methanol, intermediate 1, tetramethyltetravinylcyclotetrasiloxane, and photoinitiator are stirred and mixed, and reacted under light to generate intermediate 2. The reaction equation is as follows: .

[0008] S3: Toluene, anhydrous ethanol, and paraformaldehyde were stirred and mixed, and intermediate 2 and p-trifluoromethylphenol were added. The mixture was refluxed for 20-24 hours to generate modified benzoxazine. The reaction equation is shown below: .

[0009] In step S1, the molar ratio of 4-aminophenylboronic acid to 1-thioglycerol is 1:(1.1-1.3).

[0010] In step S2, the molar ratio of the intermediate 1 to tetramethyltetravinylcyclotetrasiloxane is (4.05-4.2):1.

[0011] In step S3, the molar ratio of p-trifluoromethylphenol to intermediate 2 is (4.1-4.2):1.

[0012] In step S2 , the photoinitiator is photoinitiator 184 .

[0013] In step (3), the preheating temperature is 140-160°C.

[0014] In step (3), the release agent is zinc stearate.

[0015] In step (3), the pressure of the hot compression molding is 20-25 MPa, and the holding time is 20-30 min.

[0016] In step (4), the heat treatment process is as follows: keeping the temperature at 140-160°C for 1-2 hours, heating to 160-180°C for 1-2 hours, and heating to 200-220°C for 3-5 hours.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: The modified benzoxazine prepared by the present invention contains siloxane, dynamic borate bonds, and fluorocarbon. When added to the components for preparing brake discs, the strength of the material can be improved by increasing the crosslinking density and absorbing energy, and the friction coefficient of the material can be reduced. This allows the high-carbon / high-alloy composite brake disc for racing cars to have excellent shear strength and impact strength, a good friction coefficient, and a low wear rate. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0019] Example 1 Preparation of modified benzoxazine: S1: Add 800 ml of tetrahydrofuran and 1.1 mol of 1-thioglycerol to a reaction kettle and stir to mix. At room temperature, add 1 mol of 4-aminophenylboronic acid in batches (10 equal batches, 15 min between each batch). Stir at 60°C for 20 h, distill under reduced pressure at 45°C for 2 h, add 500 ml of n-hexane, stir and precipitate, filter, and vacuum dry at 60°C for 24 h to obtain intermediate 1. Its H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d ) δ 7.59 - 7.47 (m, 2H), 6.79 - 6.69 (m, 2H), 4.71 - 4.10 (m, 5H), 2.64 (dddd, J = 76.1, 12.2, 6.2, 4.2 Hz, 2H), 1.73 (d, J= 12.4 Hz, 1H); S2: 600 ml of methanol, 0.405 mol of intermediate 1, 0.1 mol of tetramethyltetravinylcyclotetrasiloxane, and 1 g of photoinitiator 184 were added to a reaction kettle, stirred for 10 min, irradiated under 300 W UV light for 10 min under stirring at room temperature, and distilled under reduced pressure at 45°C for 3 h to obtain intermediate 2; its H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d) δ 7.65 -7.47 (m, 8H), 6.79 - 6.69 (m, 8H), 4.62 - 4.21 (m, 20H), 2.93 - 2.44 (m,16H), 0.95 (t, J = 8.5 Hz, 8H), 0.06 (s, 12H); S3: 600 ml of toluene, 100 ml of anhydrous ethanol, and 25 g of paraformaldehyde were added to a reaction kettle and stirred for 30 min. 0.1 mol of intermediate 2 and 0.41 mol of p-trifluoromethylphenol were added in sequence. Under nitrogen protection, the temperature was raised to reflux and the reaction was carried out for 20 h. The mixture was cooled to 60°C and distilled under reduced pressure for 3 h. The mixture was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V = 5:1) and rotary evaporated at 50°C for 3 h to obtain the modified benzoxazine. Its H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d ) δ 7.64 -7.51 (m, 16H), 7.02 - 6.90 (m, 12H), 5.38 (s, 8H), 4.65 (d, J = 0.8 Hz, 8H), 4.61 - 4.19 (m, 12H), 2.94 - 2.44 (m, 16H), 0.95 (t, J = 8.5 Hz, 8H), 0.06 (s, 12H).

[0020] Example 2 Preparation of modified benzoxazine: S1: Add 800 ml of tetrahydrofuran and 1.2 mol of 1-thioglycerol to a reactor and stir to mix. At room temperature, add 1 mol of 4-aminophenylboronic acid in batches (10 equal batches, with an interval of 15 min between each batch). Stir at 55°C for 22 h, and distill under reduced pressure at 45°C for 2 h. Add 500 ml of n-hexane and stir to precipitate. Filter and dry in a vacuum at 60°C for 24 h to obtain intermediate 1. S2: 600 ml of methanol, 0.41 mol of intermediate 1, 0.1 mol of tetramethyltetravinylcyclotetrasiloxane, and 1 g of photoinitiator 184 were added to a reaction kettle, stirred for 10 min, irradiated under 300 W UV light for 15 min under stirring at room temperature, and distilled under reduced pressure at 45 °C for 3 h to obtain intermediate 2; S3: 600 ml of toluene, 100 ml of anhydrous ethanol, and 25 g of paraformaldehyde were added to a reactor and stirred for 30 min. 0.1 mol of intermediate 2 and 0.415 mol of p-trifluoromethylphenol were added in sequence. Under nitrogen protection, the temperature was raised to reflux and the reaction was carried out for 22 h. The mixture was cooled to 60 °C and distilled under reduced pressure for 3 h. The mixture was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V = 5:1) and rotary evaporated at 50 °C for 3 h to obtain the modified benzoxazine.

[0021] Example 3 Preparation of modified benzoxazine: S1: Add 800 ml of tetrahydrofuran and 1.3 mol of 1-thioglycerol to a reactor and stir to mix. At room temperature, add 1 mol of 4-aminophenylboronic acid in batches (10 equal batches, with an interval of 15 min between each batch). Stir at 50°C for 24 h, and distill under reduced pressure at 45°C for 2 h. Add 500 ml of n-hexane and stir to precipitate. Filter and dry in a vacuum at 60°C for 24 h to obtain intermediate 1. S2: 600 ml of methanol, 0.42 mol of intermediate 1, 0.1 mol of tetramethyltetravinylcyclotetrasiloxane, and 1 g of photoinitiator 184 were added to a reaction kettle, stirred for 10 min, irradiated under 300 W UV light for 20 min under stirring at room temperature, and distilled under reduced pressure at 45 °C for 3 h to obtain intermediate 2; S3: 600 ml of toluene, 100 ml of anhydrous ethanol, and 25 g of paraformaldehyde were added to a reactor and stirred for 30 min. 0.1 mol of intermediate 2 and 0.42 mol of trifluoromethylphenol were added in sequence. Under nitrogen protection, the temperature was raised to reflux and the reaction was carried out for 24 h. The mixture was cooled to 60 °C and distilled under reduced pressure for 3 h. The mixture was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V = 5:1) and rotary evaporated at 50 °C for 3 h to obtain the modified benzoxazine.

[0022] Example 4 Preparation of high carbon / high alloy composite brake disc for racing car: (1) Weigh: 25 kg of phenolic resin, 10 kg of modified benzoxazine (prepared in Example 1), 8 kg of pulverized mild steel fiber, 4 kg of reduced iron powder, 8 kg of brass fiber, 5 kg of para-aramid pulp, and 8 kg of flake graphite; (2) Add the above materials into a high-speed mixer and mix at a speed of 300 rpm for 25 minutes; (3) Preheat the mold to 140°C and evenly apply zinc stearate release agent on the inner wall of the mold; then pour the mixture into the mold and perform hot molding. Set the pressure to 20 MPa, vent once every 10 seconds, vent three times in total, and then maintain the pressure for 30 minutes; (4) Place the mold containing the sample in a drying oven, set the temperature to 140°C, keep it warm for 2 hours, increase the temperature to 160°C, keep it warm for 2 hours, increase the temperature to 200°C, keep it warm for 5 hours, cool it naturally to room temperature, demold, and obtain a high-carbon / high-alloy composite brake disc for racing.

[0023] Example 5 Preparation of high carbon / high alloy composite brake disc for racing car: (1) Weigh: 28 kg of phenolic resin, 12 kg of modified benzoxazine (prepared in Example 2), 9 kg of pulverized mild steel fiber, 5 kg of reduced iron powder, 9 kg of brass fiber, 6 kg of para-aramid pulp, and 9 kg of flake graphite; (2) Add the above materials into a high-speed mixer and mix at a speed of 300 rpm for 30 minutes; (3) Preheat the mold to 150°C and evenly apply zinc stearate release agent on the inner wall of the mold; then pour the mixture into the mold and perform hot molding. Set the pressure to 23 MPa, vent once every 10 seconds, vent three times in total, and then maintain the pressure for 25 minutes; (4) Place the mold containing the sample in a drying oven, set the temperature to 150°C, keep it warm for 1.5 hours, increase the temperature to 170°C, keep it warm for 1.5 hours, increase the temperature to 210°C, keep it warm for 4 hours, cool it naturally to room temperature, demold it, and obtain a high-carbon / high-alloy composite brake disc for racing.

[0024] Example 6 Preparation of high carbon / high alloy composite brake disc for racing car: (1) Weigh: 30 kg of phenolic resin, 15 kg of modified benzoxazine (prepared in Example 3), 10 kg of pulverized mild steel fiber, 6 kg of reduced iron powder, 10 kg of brass fiber, 8 kg of para-aramid pulp, and 10 kg of flake graphite; (2) Add the above materials into a high-speed mixer and mix at a speed of 300 rpm for 35 minutes; (3) Preheat the mold to 160°C and evenly apply zinc stearate release agent on the inner wall of the mold; then pour the mixture into the mold and perform hot molding. Set the pressure to 25 MPa, vent once every 10 seconds, vent three times in total, and then maintain the pressure for 20 minutes; (4) Place the mold containing the sample in a drying oven, set the temperature to 160°C, keep it warm for 1 hour, increase the temperature to 180°C, keep it warm for 1 hour, increase the temperature to 220°C, keep it warm for 3 hours, cool it naturally to room temperature, demold, and obtain a high-carbon / high-alloy composite brake disc for racing.

[0025] Comparative Example 1 The preparation method of the high carbon / high alloy composite brake disc for racing car is basically the same as that of Example 5, except that the modified benzoxazine is not added to the components.

[0026] Comparative Example 2 The preparation method of the high carbon / high alloy composite brake disc for racing cars is basically the same as that of Example 5, except that the modified benzoxazine (prepared in Example 2) is replaced by an equal weight of modified benzoxazine prepared by the following method: S1: Add 600 ml of methanol, 0.41 mol of 4-aminothiophenol, 0.1 mol of tetramethyltetravinylcyclotetrasiloxane, and 1 g of photoinitiator 184 into a reactor, stir at room temperature for 10 min, irradiate under 300 W UV light for 15 min under stirring, and distill under reduced pressure at 45°C for 3 h to obtain an intermediate; S2: Add 600 ml of toluene, 100 ml of anhydrous ethanol, and 25 g of paraformaldehyde into a reactor and stir for 30 minutes. Then, add 0.1 mol of the intermediate and 0.415 mol of trifluoromethylphenol in sequence. Under nitrogen protection, heat to reflux and react for 22 hours. Cool to 60°C and distill under reduced pressure for 3 hours. Purify using silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V=5:1) and rotary evaporate at 50°C for 3 hours to obtain the modified benzoxazine.

[0027] Comparative Example 3 The preparation method of the high carbon / high alloy composite brake disc for racing cars is basically the same as that of Example 5, except that the modified benzoxazine (prepared in Example 2) is replaced by an equal weight of modified benzoxazine prepared by the following method: The preparation method of the modified benzoxazine is substantially the same as that of Example 2, except that the tetramethyltetravinylcyclotetrasiloxane in step S2 is replaced by an equal molar amount of 1,3-diallyltetramethyldisilane.

[0028] Comparative Example 4 The preparation method of the high carbon / high alloy composite brake disc for racing cars is basically the same as that of Example 5, except that the modified benzoxazine (prepared in Example 2) is replaced by an equal weight of modified benzoxazine prepared by the following method: The preparation method of the modified benzoxazine is substantially the same as that of Example 2, except that the p-trifluoromethylphenol in step S3 is replaced by an equimolar amount of phenol.

[0029] The phenolic resin model used in this application is PF-214, produced by Shandong Chenghui New Materials Co., Ltd.; the reduced iron powder model is FRH100.27, produced by Gongyi Renhe Metallurgical Materials Co., Ltd.; the low-carbon steel crushed fiber model is SS-1110, and the brass fiber model is SVB-6030, produced by Zhangjiagang Xinli Metal Co., Ltd.; the para-aramid pulp model is F1128, produced by Yantai Taihexing Materials Technology Co., Ltd.; the flake graphite model is 595, produced by Qingdao Jinhui Graphite Co., Ltd.

[0030] The brake discs prepared in Examples 4-6 and the comparative example were subjected to shear strength, friction coefficient and impact strength tests. The shear strength test was conducted in accordance with GB / T 22309-2008, the test fixture was a 6.2.3 disc brake pad fixture, and the sample size was 50 mm × 20 mm × 10 mm. The friction coefficient, wear rate and impact strength tests were conducted in accordance with GB 5763-2008. The sample sizes for the friction coefficient and wear rate tests were 25 mm × 25 mm × 5 mm, the test temperature was 350°C, and the sample size for the impact strength test was 55 mm × 10 mm × 6 mm.

[0031] Table 1 Performance test data table

[0032] It can be seen from Examples 4, 5 and 6 in Table 1 that the high carbon / high alloy composite brake disc for racing cars prepared by the present invention has excellent shear strength and impact strength, a good friction coefficient and a low wear rate.

[0033] The high-carbon / high-alloy composite brake disc for racing cars prepared by the present invention exhibits excellent shear strength, friction coefficient, and impact strength. This is due to the modified benzoxazine containing a benzoxazine structure, siloxane, dynamic borate bonds, and fluorocarbon. The benzoxazine structure undergoes ring opening upon heating, reacting with the ortho-hydroxyl groups in the phenolic resin to form a curing reaction. The four-arm structure of the modified benzoxazine provides more crosslinking sites, effectively resisting interchain slip and improving the material's strength. The siloxane within the rigid crosslinked network induces plastic deformation (such as crazing and shear yielding) in the phenolic resin, absorbing impact energy and enhancing the material's impact strength. The borate bonds undergo reversible rupture and reformation under stress, effectively dissipating energy and preventing rapid crack propagation, thereby maintaining and potentially improving the material's effective mechanical properties under cyclic loading or damage. The fluorocarbon has extremely low surface energy and excellent lubricity, preventing a sharp drop in the friction coefficient under high-speed and high-temperature conditions. It also effectively reduces adhesion and interaction between friction components, thereby reducing material wear.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a high-carbon / high-alloy composite brake disc for racing, characterized in that: The following steps are involved: (1) Weigh by weight: 25-30 parts of phenolic resin, 10-15 parts of modified benzoxazine, 8-10 parts of low carbon steel crushed fiber, 4-6 parts of reduced iron powder, 8-10 parts of brass fiber, 5-8 parts of para-aramid pulp, and 8-10 parts of flake graphite. (2) Add the above materials into the mixer and mix them evenly to obtain a mixture. (3) Preheat the mold, apply release agent on the inner wall of the mold, pour in the mixture, and hot mold forming. (4) Heat-treating and demoulding the mold containing the sample to obtain the product; The preparation method of the modified benzoxazine comprises the following steps: firstly, 4-aminophenylboronic acid reacts with 1-thioglycerol to generate intermediate 1; then, intermediate 1 reacts with tetramethyltetravinylcyclotetrasiloxane to generate intermediate 2; and finally, intermediate 2 reacts with p-trifluoromethylphenol under the action of paraformaldehyde to obtain the modified benzoxazine.

2. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 1, characterized in that: The modified benzoxazine is prepared by the following method: S1: Tetrahydrofuran and 4-aminophenylboronic acid were stirred and mixed, 1-thioglycerol was added, and the mixture was reacted at 50-60°C for 20-24 hours to generate intermediate 1; S2: Methanol, intermediate 1, tetramethyltetravinylcyclotetrasiloxane, and a photoinitiator are stirred and mixed, and reacted under light to generate intermediate 2; S3: Toluene, anhydrous ethanol, and paraformaldehyde were stirred and mixed, and intermediate 2 and p-trifluoromethylphenol were added, and the mixture was refluxed for 20-24 hours to generate modified benzoxazine.

3. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 2, characterized in that: In step S1, the molar ratio of 4-aminophenylboronic acid to 1-thioglycerol is 1:(1.1-1.3).

4. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 2, characterized in that: In step S2, the molar ratio of the intermediate 1 to tetramethyltetravinylcyclotetrasiloxane is (4.05-4.2):

1.

5. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 2, characterized in that: In step S3, the molar ratio of p-trifluoromethylphenol to intermediate 2 is (4.1-4.2):

1.

6. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 2, characterized in that: In step S2 , the photoinitiator is photoinitiator 184 .

7. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 1, characterized in that: In step (3), the preheating temperature is 140-160°C.

8. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 1, characterized in that: In step (3), the release agent is zinc stearate.

9. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 1, characterized in that: In step (3), the pressure of the hot compression molding is 20-25 MPa, and the holding time is 20-30 min.

10. The method for preparing a high-carbon / high-alloy composite brake disc for racing car according to claim 1, characterized in that: In step (4), the heat treatment process is as follows: keeping the temperature at 140-160°C for 1-2 hours, heating to 160-180°C for 1-2 hours, and heating to 200-220°C for 3-5 hours.

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