A method for manufacturing a high-carbon / high-alloy composite brake disc for a racing car

Abstract

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

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of brake disc manufacturing, in particular to a preparation method of a high-carbon / high-alloy composite brake disc for racing cars. BACKGROUND

[0002] Since a racing car brake disc needs to maintain high performance under the conditions of high-speed driving and frequent braking, high requirements are put forward for the material of the brake disc, the brake disc must have high wear resistance, high thermal stability, good shear strength and sufficient impact strength, so that the brake disc can still maintain good braking performance under high temperature and high stress environment, the braking distance is reduced, and the safety and maneuverability of the racing car are improved. Although the traditional brake disc materials such as cast iron and steel have certain strength and wear resistance, they are prone to thermal fatigue and thermal cracks at high temperatures, which leads to a decrease in braking performance. In addition, the density of cast iron and steel is relatively large, which increases the non-suspended mass of the vehicle, which is not conducive to the lightweight design of the racing car. The brake disc also has problems such as unstable friction coefficient and poor shear strength, which affect the safety and maneuverability of the racing car.

[0003] A Chinese patent with the publication number CN106966751A discloses a high-performance low-cost C / C-SiC composite brake disc and a preparation method and application thereof. The preparation method comprises: carbonizing the brake disc preform, densifying the carbonized brake disc preform by using a chemical vapor deposition method; then performing heat treatment in an inert atmosphere; then performing mechanical processing; then performing treatment by using a molten silicon infiltration method; then performing treatment by using a chemical vapor deposition method or a precursor impregnation and pyrolysis method; and finally mechanically processing the obtained product into the final design size to obtain the composite brake disc finished product. The C / C-SiC composite brake disc and the preparation method thereof provided by the application can reduce the preparation cost, improve the heat conduction performance and friction and wear performance of the brake disc, but the shear strength is poor. SUMMARY

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

[0005] To achieve the above-mentioned purpose, the present application realizes the following technical scheme:

[0006] A preparation method of a high-carbon / high-alloy composite brake disc for racing cars, comprising the following steps:

[0007] (1) weigh the following components: phenolic resin 25-30 parts, modified benzoxazine 10-15 parts, low-carbon steel crushed fiber 8-10 parts, reduced iron powder 4-6 parts, brass fiber 8-10 parts, para-aramid pulp 5-8 parts, and flake graphite 8-10 parts,

[0008] (2) The above materials are added into a mixer to mix uniformly to obtain a mixture,

[0009] (3) The mold is preheated, the inner wall of the mold is smeared with a release agent, the mixture is poured into the mold, and hot mold pressing is performed,

[0010] (4) The mold with the sample is subjected to heat treatment and demolding, and thus the modified benzoxazine is obtained.

[0011] The preparation method of the modified benzoxazine is as follows: first, 4-aminobenzene boronic acid is reacted with 1-thioglycerol to generate an intermediate 1, then the intermediate 1 is reacted with tetramethyltetra-vinylcyclotetrasiloxane to generate an intermediate 2, and finally the intermediate 2 is reacted with p-trifluoromethyl phenol under the action of paraformaldehyde to obtain the modified benzoxazine.

[0012] The modified benzoxazine is prepared by the following method:

[0013] S1: Tetrahydrofuran, 4-aminobenzene boronic acid are stirred and uniformly mixed, 1-thioglycerol is added, and intermediate 1 is generated by reacting at 50-60°C for 20-24h, and the reaction equation is as follows:

[0014] .

[0015] S2: Methanol, intermediate 1, tetramethyltetra-vinylcyclotetrasiloxane, and a photoinitiator are stirred and uniformly mixed, and intermediate 2 is generated by reacting under light, and the reaction equation is as follows:

[0016] .

[0017] S3: Toluene, anhydrous ethanol, and paraformaldehyde are stirred and uniformly mixed, intermediate 2 and p-trifluoromethyl phenol are added, and the modified benzoxazine is generated by refluxing for 20-24h, and the reaction equation is as follows:

[0018] .

[0019] In step S1, the molar ratio of 4-aminobenzene boronic acid to 1-thioglycerol is 1:(1.1-1.3).

[0020] In step S2, the molar ratio of intermediate 1 to tetramethyltetra-vinylcyclotetrasiloxane is (4.05-4.2):1.

[0021] In step S3, the molar ratio of p-trifluoromethyl phenol to intermediate 2 is (4.1-4.2):1.

[0022] In step S2, the photoinitiator is photoinitiator 184.

[0023] In step (3), the preheating temperature is 140-160°C.

[0024] In step (3), the release agent is zinc stearate.

[0025] In step (3), the pressure of the hot die forming is 20-25 MPa, and the pressure holding time is 20-30 min.

[0026] In step (4), the heat treatment process is as follows: temperature 140-160℃, holding for 1-2h, temperature 160-180℃, holding for 1-2h, temperature 200-220℃, holding for 3-5h.

[0027] By adopting the above technical solutions, the application has the following beneficial effects:

[0028] The modified benzoxazine prepared by the application contains siloxane, dynamic borate bond and fluorocarbon. When the modified benzoxazine is added to the brake disc preparation components, 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, so that the high-carbon / high-alloy composite brake disc for racing cars has excellent shear strength and impact strength, good friction coefficient and low wear rate. DETAILED DESCRIPTION

[0029] The application will be further described below in combination with examples, but the application is not limited to these examples.

[0030] Example 1: Preparation of modified benzoxazine

[0031] S1: 800ml of tetrahydrofuran and 1.1mol of 1-thioglycerol were added to a reaction kettle, stirred and uniformly mixed, 1mol of 4-aminobenzene boronic acid was added in batches at room temperature (divided into 10 batches, with an interval of 15min), stirred at 60℃ for 20h, distilled at 45℃ under reduced pressure for 2h, 500ml of n-hexane was added and stirred to precipitate, filtered, and vacuum dried at 60℃ for 24h to obtain intermediate 1; the nuclear magnetic resonance hydrogen spectrum data of intermediate 1 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);

[0032] S2: 600ml of methanol, 0.405mol of intermediate 1, 0.1mol of tetramethyltetra-vinylcyclotetrasiloxane and 1g of photoinitiator 184 were added to a reaction kettle, stirred for 10min, and then irradiated for 10min under the condition of room temperature stirring and 300W ultraviolet light. Then, 45℃ reduced pressure distillation was performed for 3h to obtain intermediate 2; the nuclear magnetic resonance hydrogen spectrum data of intermediate 2 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);

[0033] S3: 600 ml of toluene, 100 ml of anhydrous ethanol, 25 g of paraformaldehyde were added to the reaction kettle, stirred for 30 min, 0.1 mol of intermediate 2 and 0.41 mol of p-trifluoromethyl phenol were added in turn, under nitrogen protection, the temperature was raised to reflux, and the reaction was carried out for 20 h. After cooling to 60°C, it was distilled under reduced pressure for 3 h, 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. The nuclear magnetic resonance hydrogen 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).

[0034] Example 2 Preparation of modified benzoxazine:

[0035] S1: 800 ml of tetrahydrofuran, 1.2 mol of 1-thioglycerol were added to the reaction kettle, stirred and mixed uniformly, 1 mol of 4-aminobenzene boronic acid was added in batches at room temperature (divided into 10 batches, each batch interval 15 min), stirred at 55°C for 22 h, distilled under reduced pressure at 45°C for 2 h, added 500 ml of n-hexane and stirred to precipitate, filtered, and vacuum dried at 60°C for 24 h to obtain intermediate 1;

[0036] S2: 600 ml of methanol, 0.41 mol of intermediate 1, 0.1 mol of tetramethyltetra vinyl cyclosiloxane, and 1 g of photoinitiator 184 were added to the reaction kettle, stirred for 10 min, and irradiated under 300 W ultraviolet light for 15 min under room temperature stirring conditions. Distilled under reduced pressure at 45°C for 3 h to obtain intermediate 2;

[0037] S3: Add 600 ml toluene, 100 ml anhydrous ethanol, and 25 g paraformaldehyde to a reaction vessel and stir for 30 min. Then add 0.1 mol intermediate 2 and 0.415 mol p-trifluoromethylphenol sequentially. Under nitrogen protection, heat to reflux and react for 22 h. Cool to 60 °C and distill under reduced pressure for 3 h. Purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V=5:1). Rotary distill at 50 °C for 3 h to obtain modified benzoxazine.

[0038] Example 3 Preparation of modified benzoxazine:

[0039] S1: Add 800 ml of tetrahydrofuran and 1.3 mol of 1-thioglycerol to the reaction vessel, stir and mix well. At room temperature, add 1 mol of 4-aminophenylboronic acid in batches (divided into 10 batches, with an interval of 15 min between each batch). Stir at 50 °C for 24 h, distill under reduced pressure at 45 °C for 2 h, add 500 ml of n-hexane and stir to precipitate, filter, and dry under vacuum at 60 °C for 24 h to obtain intermediate 1.

[0040] S2: Add 600 ml of methanol, 0.42 mol of intermediate 1, 0.1 mol of tetramethyltetravinylcyclotetrasiloxane, and 1 g of photoinitiator 184 to a reaction vessel, stir for 10 min, irradiate under 300 W ultraviolet light for 20 min under stirring at room temperature, and distill under reduced pressure at 45 °C for 3 h to obtain intermediate 2.

[0041] S3: Add 600ml toluene, 100ml anhydrous ethanol, and 25g paraformaldehyde to a reaction vessel and stir for 30min. Then add 0.1mol intermediate 2 and 0.42mol p-trifluoromethylphenol sequentially. Under nitrogen protection, heat to reflux and react for 24h. Cool to 60℃ and distill under reduced pressure for 3h. Purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V=5:1). Rotary distill at 50℃ for 3h to obtain modified benzoxazine.

[0042] Example 4: Preparation of high-carbon / high-alloy composite brake discs for racing cars:

[0043] (1) Weigh out: 25 kg of phenolic resin, 10 kg of modified benzoxazine (prepared in Example 1), 8 kg of low carbon steel crushed fiber, 4 kg of reduced iron powder, 8 kg of brass fiber, 5 kg of para-aramid pulp, and 8 kg of flake graphite.

[0044] (2) Add the above materials into a high-speed mixer and mix at 300 rpm for 25 minutes;

[0045] (3) Preheat the mold to 140°C, and apply zinc stearate release agent evenly to the inner wall of the mold; then pour in the mixture, hot mold molding, set the pressure to 20MPa, vent once every 10s, vent three times in total, and then hold the pressure for 30min;

[0046] (4) Place the mold containing the sample into a drying oven, set the temperature to 140℃, keep it warm for 2 hours, raise the temperature to 160℃, keep it warm for 2 hours, raise the temperature to 200℃, 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 cars.

[0047] Example 5: Preparation of high-carbon / high-alloy composite brake discs for racing cars:

[0048] (1) Weigh out: 28 kg of phenolic resin, 12 kg of modified benzoxazine (prepared in Example 2), 9 kg of low carbon steel crushed fiber, 5 kg of reduced iron powder, 9 kg of brass fiber, 6 kg of para-aramid pulp, and 9 kg of flake graphite;

[0049] (2) Add the above materials into a high-speed mixer and mix at 300 rpm for 30 minutes;

[0050] (3) Preheat the mold to 150°C, and apply zinc stearate release agent evenly to the inner wall of the mold; then pour in the mixture, hot mold molding, set the pressure to 23MPa, vent once every 10s, vent three times in total, and then hold the pressure for 25min;

[0051] (4) Place the mold containing the sample into a drying oven, set the temperature to 150℃, keep it at that temperature for 1.5h, raise the temperature to 170℃, keep it at that temperature for 1.5h, raise the temperature to 210℃, keep it at that temperature for 4h, let it cool naturally to room temperature, demold, and obtain a high carbon / high alloy composite brake disc for racing cars.

[0052] Example 6: Preparation of high-carbon / high-alloy composite brake discs for racing cars:

[0053] (1) Weigh out: 30 kg of phenolic resin, 15 kg of modified benzoxazine (prepared in Example 3), 10 kg of low carbon steel crushed fiber, 6 kg of reduced iron powder, 10 kg of brass fiber, 8 kg of para-aramid pulp, and 10 kg of flake graphite.

[0054] (2) Add the above materials into a high-speed mixer and mix at 300 rpm for 35 minutes;

[0055] (3) Preheat the mold to 160°C, and apply zinc stearate release agent evenly to the inner wall of the mold; then pour in the mixture, hot mold molding, set the pressure to 25MPa, vent once every 10s, vent three times in total, and then hold the pressure for 20min;

[0056] (4) Place the mold containing the sample into a drying oven, set the temperature to 160℃, keep it at that temperature for 1 hour, raise the temperature to 180℃, keep it at that temperature for 1 hour, raise the temperature to 220℃, keep it at that temperature for 3 hours, let it cool naturally to room temperature, demold, and obtain a high carbon / high alloy composite brake disc for racing cars.

[0057] Comparative Example 1

[0058] The preparation method of the high carbon / high alloy composite brake disc for racing cars is basically the same as that in Example 5, except that modified benzoxazine is not added to the components.

[0059] Comparative Example 2

[0060] The preparation method of the high-carbon / high-alloy composite brake disc for racing cars is basically the same as that in Example 5, except that the modified benzoxazine (prepared in Example 2) is replaced with an equal weight of the modified benzoxazine prepared by the following method:

[0061] S1: Add 600 ml of methanol, 0.41 mol of 4-aminobenzylthiophenol, 0.1 mol of tetramethyltetravinylcyclotetrasiloxane, and 1 g of photoinitiator 184 to a reaction vessel, stir at room temperature for 10 min, irradiate under 300 W ultraviolet light for 15 min under stirring conditions, and distill under reduced pressure at 45 °C for 3 h to obtain the intermediate.

[0062] S2: Add 600 ml toluene, 100 ml anhydrous ethanol, and 25 g paraformaldehyde to a reaction vessel and stir for 30 min. Then add 0.1 mol of intermediate and 0.415 mol of p-trifluoromethylphenol sequentially. Under nitrogen protection, heat to reflux and react for 22 h. Cool to 60 °C and distill under reduced pressure for 3 h. Purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V=5:1). Rotary distill at 50 °C for 3 h to obtain modified benzoxazine.

[0063] Comparative Example 3

[0064] The preparation method of the high-carbon / high-alloy composite brake disc for racing cars is basically the same as that in Example 5, except that the modified benzoxazine (prepared in Example 2) is replaced with an equal weight of the modified benzoxazine prepared by the following method:

[0065] The preparation method of modified benzoxazine is basically the same as that in Example 2, except that tetramethyltetravinylcyclotetrasiloxane in step S2 is replaced with an equimolar amount of 1,3-diallyltetramethyldisilane.

[0066] Comparative Example 4

[0067] The preparation method of the high-carbon / high-alloy composite brake disc for racing cars is basically the same as that in Example 5, except that the modified benzoxazine (prepared in Example 2) is replaced with an equal weight of the modified benzoxazine prepared by the following method:

[0068] The preparation method of modified benzoxazine is basically the same as that in Example 2, except that p-trifluoromethylphenol in step S3 is replaced with an equimolar amount of phenol.

[0069] The phenolic resin used in this application is PF-214, produced by Shandong Chenghui New Materials Co., Ltd.; the reduced iron powder is FRH100.27, produced by Gongyi Renhe Metallurgical Materials Co., Ltd.; the low-carbon steel crushed fiber is SS-1110, the brass fiber is SVB-6030, produced by Zhangjiagang Xinli Metal Co., Ltd.; the para-aramid pulp is F1128, produced by Yantai Taihexing Materials Technology Co., Ltd.; and the flake graphite is 595, produced by Qingdao Jinhui Graphite Co., Ltd.

[0070] The brake discs prepared in Examples 4-6 and the comparative examples were subjected to shear strength, coefficient of friction, and impact strength tests. The shear strength test was conducted according to GB / T 22309-2008, using the 6.2.3 disc brake block fixture, with a sample size of 50mm×20mm×10mm. The coefficient of friction, wear rate, and impact strength tests were conducted according to GB 5763-2008. The sample size for the coefficient of friction and wear rate tests was 25mm×25mm×5mm, and the test temperature was 350℃. The sample size for the impact strength test was 55mm×10mm×6mm.

[0071] Table 1 Performance Test Data

[0072]

[0073] As can be seen from Examples 4, 5, and 6 in Table 1, the high-carbon / high-alloy composite brake disc for racing cars prepared by the present invention has excellent shear strength and impact strength, good coefficient of friction, and low wear rate.

[0074] The high-carbon / high-alloy composite brake disc for racing cars prepared by this invention exhibits excellent shear strength, coefficient of friction, and impact strength. This is because the modified benzoxazine contains a benzoxazine structure, siloxane, dynamic borate ester bonds, and fluorocarbon. Under heating conditions, the benzoxazine structure undergoes ring-opening and a curing reaction with the ortho-position of the phenolic hydroxyl groups in the phenolic resin. The four-arm structure of the modified benzoxazine provides more crosslinking sites, effectively resisting slippage between molecular chains and improving the material's strength. Siloxane, within a rigid crosslinking network, can induce plastic deformation (such as crimping and shear yielding) in the phenolic resin, absorbing impact energy and improving the material's impact strength. Borate ester bonds, under stress, can undergo reversible fracture and recombination, effectively dissipating energy and preventing rapid crack propagation, thereby maintaining and potentially enhancing the material's effective mechanical properties under cyclic loading or damage conditions. Fluorocarbon possesses extremely low surface energy and excellent lubricity, preventing a sharp decrease in the coefficient of friction under high-speed and high-temperature conditions, and effectively reducing adhesion and interaction forces between friction components, thus lowering the material's wear rate.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a high-carbon / high-alloy composite brake disc for racing cars, characterized in that, Includes the following steps: (1) Weigh out the following by weight: 25-30 parts of phenolic resin, 10-15 parts of modified benzoxazine, 8-10 parts of low-carbon steel pulverized 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 to the mixer and mix evenly to obtain a mixture. (3) Preheat the mold, apply release agent to the inner wall of the mold, pour in the mixture, and hot-press to form. (4) Heat-treat and demold the mold containing the sample to obtain the final product; The modified benzoxazine is prepared by reacting 4-aminophenylboronic acid with 1-thioglycerol to generate intermediate 1, then reacting intermediate 1 with tetramethyltetravinylcyclotetrasiloxane to generate intermediate 2, and finally reacting intermediate 2 with p-trifluoromethylphenol in the presence of paraformaldehyde. The structural formula of intermediate 1 is shown below: ； The structural formula of intermediate 2 is shown below: ； The structural formula of the modified benzoxazine is shown below: 。 2. The method for preparing a high-carbon / high-alloy composite brake disc for racing cars according to claim 1, characterized in that, The modified benzoxazine was prepared by the following method: S1: Tetrahydrofuran and 4-aminophenylboronic acid are stirred and mixed, then 1-thioglycerol is added and reacted at 50-60℃ for 20-24h to generate intermediate 1; S2: Methanol, intermediate 1, tetramethyltetravinylcyclotetrasiloxane and photoinitiator are stirred and mixed, and reacted under light to generate intermediate 2; S3: Mix toluene, anhydrous ethanol, and paraformaldehyde thoroughly, add intermediate 2 and p-trifluoromethylphenol, and reflux for 20-24 hours to generate modified benzoxazine.

3. The method for preparing a high-carbon / high-alloy composite brake disc for racing cars 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 cars according to claim 2, characterized in that, In step S2, the molar ratio of 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 cars 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 cars 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 cars according to claim 1, characterized in that, In step (3), the preheating temperature is 140-160℃.

8. The method for preparing a high-carbon / high-alloy composite brake disc for racing cars 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 cars according to claim 1, characterized in that, In step (3), the pressure of hot 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 cars according to claim 1, characterized in that, In step (4), the heat treatment process is as follows: temperature 140-160℃, hold for 1-2 hours, temperature rise to 160-180℃, hold for 1-2 hours, temperature rise to 200-220℃, hold for 3-5 hours.

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