Anti-aging rubber material and preparation method thereof

Abstract

The invention discloses an anti-aging rubber material and a preparation method thereof, and relates to the technical field of high polymer materials. When the anti-aging rubber material is prepared, 4, 4 '-diaminodiphenylamine and 3, 5-bis (tert-butyl)-4-hydroxybenzene propionyl chloride are subjected to a reaction to prepare an anti-aging agent; reacting the maleic anhydride grafted ethylene propylene diene monomer with an anti-aging agent to obtain modified ethylene propylene diene monomer; reacting the carboxylated carbon nano tube with 3-(diphenylphosphino) propylamine to prepare a pre-modified carbon nano tube; reacting the pre-modified carbon nano tube with 2-(3-chloropropyl)-4, 6-dimethyl-1, 3, 5-triazine, so as to obtain a modified carbon nano tube; mixing the modified ethylene propylene diene monomer, the modified carbon nanotubes, zinc oxide, stearic acid, carbon black, paraffin oil, sulfur, an accelerant TMTD and an accelerant M, and performing hot pressing to obtain the anti-aging rubber material. The anti-aging rubber material prepared by the invention has good anti-aging, flame-retardant, antistatic and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an aging-resistant rubber material and its preparation method. Background Technology

[0002] Ethylene propylene diene monomer (EPDM) rubber, as a high-quality rubber material, possesses advantages such as aging resistance, corrosion resistance, and good weather resistance, which to some extent meets the material performance requirements of nuclear energy equipment. However, traditional EPDM rubber materials still face significant challenges under high-dose irradiation environments, easily exhibiting irradiation damage and performance degradation, thus limiting its application in the nuclear energy field. Simultaneously, EPDM rubber is also a flammable electrical insulating material with a limiting oxygen index of only about 20%. Due to its high resistivity, once EPDM rubber accumulates static electricity, it is difficult to eliminate. When the accumulated charge reaches a certain amount, it can trigger electrostatic discharge, causing serious hazards. Therefore, the research and development of rubber materials with irradiation aging resistance, flame retardancy, and antistatic properties has become an urgent technical challenge. Summary of the Invention

[0003] The purpose of this invention is to provide an aging-resistant rubber material and its preparation method, so as to solve the problems existing in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An aging-resistant rubber material is obtained by mixing and hot pressing modified EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black, paraffin oil, sulfur, accelerator TMTD, and accelerator M.

[0005] As an optimization, the modified EPDM rubber is prepared by reacting maleic anhydride-grafted EPDM rubber with an antioxidant.

[0006] As an optimization, the antioxidant is prepared by reacting 4,4'-diaminodiphenylamine with 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride.

[0007] As an optimization, the modified carbon nanotubes are prepared by reacting carboxylated carbon nanotubes with 3-(diphenylphosphino)propylamine to obtain pre-modified carbon nanotubes, which are then reacted with 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine.

[0008] As an optimization, the carboxylated carbon nanotubes have a length of 0.5~2μm and a diameter of 20~30nm, and were purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd.

[0009] As an optimization, the grafting rate of the maleic anhydride-grafted EPDM rubber is 1.5%, and it was purchased from Yangzhou Heng Hui Chemical Co., Ltd.

[0010] As an optimization, the zinc oxide has a particle size of 50 nm and was purchased from Chengdu Kelong Reagent Factory.

[0011] As an optimization, the carbon black is of type N330 and was purchased from Longchang Carbon Black Co., Ltd.

[0012] As an optimization, the paraffin oil was purchased from Chengdu Kelong Reagent Factory.

[0013] A method for preparing an aging-resistant rubber material includes the following preparation steps: (1) Under a nitrogen atmosphere, at 0~4℃, 4,4'-diaminodiphenylamine, triethylamine and tetrahydrofuran are mixed evenly, and a tetrahydrofuran solution of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride is added. The mixture is stirred at 50~60℃ for 10~12h, and then distilled under reduced pressure, washed and dried to obtain an antioxidant. (2) Maleic anhydride-grafted EPDM rubber, antioxidant, and N,N-dimethylformamide are mixed evenly and stirred at 35~45℃ for 10~12h. The mixture is then distilled under reduced pressure, washed, and dried to obtain modified EPDM rubber. (3) Carboxylated carbon nanotubes, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexylcarboimide and tetrahydrofuran are mixed evenly and stirred at 20~30℃ for 4~6h. After centrifugation, washing and drying, pre-modified carbon nanotubes are obtained. Under nitrogen atmosphere, pre-modified carbon nanotubes, 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine and N,N-dimethylformamide are mixed evenly and stirred at 100~120℃ for 70~72h. After cooling to room temperature, modified carbon nanotubes are obtained by centrifugation, washing and drying. (4) Add modified EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black and paraffin oil to a two-roll mill and mix at 50°C for 10-15 min. Add sulfur, accelerator TMTD and accelerator M and continue mixing for 5-10 min. After passing through a thin mill 10 times, roll it out into sheets and leave it at room temperature for 10-12 h. Repeat the thin milling and sheeting 3 times and place it in a mold. Hot press at 150°C and 10 MPa for 20 min to obtain an aging-resistant rubber material.

[0014] As an optimization, the preparation steps of the antioxidant in step (1) are as follows: Under a nitrogen atmosphere, at 0~4℃, 4,4'-diaminodiphenylamine, triethylamine, and tetrahydrofuran are mixed evenly in a mass ratio of 1:(0.35~0.37):(5~10), and a tetrahydrofuran solution of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride is added. The mixture is stirred and reacted at 50~60℃ for 10~12h. The tetrahydrofuran is removed by vacuum distillation, and the mixture is washed 3~5 times with deionized water. The mixture is then vacuum dried at 40~50℃ for 10~12h to obtain the antioxidant.

[0015] As an optimization, the preparation steps of the modified EPDM rubber in step (2) are as follows: maleic anhydride-grafted EPDM rubber, antioxidant, and N,N-dimethylformamide are mixed evenly at a mass ratio of 1:(0.12~0.16):(10~12), stirred and reacted at 35~45℃ for 10~12h, N,N-dimethylformamide is removed by vacuum distillation, washed 3~5 times with anhydrous ethanol, and vacuum dried at 40~50℃ for 10~12h to obtain the modified EPDM rubber.

[0016] As an optimization, the preparation steps of the modified carbon nanotubes in step (3) are as follows: carboxylated carbon nanotubes, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexylcarboimide, and tetrahydrofuran are mixed evenly in a mass ratio of 1:(1.5~2):(0.1~0.2):(10~20), stirred and reacted at 20~30℃ for 4~6h, centrifuged, and the resulting precipitate was washed 3~5 times with anhydrous ethanol and vacuum dried at 50~60℃ for 10~12h to obtain the pre-modified carbon nanotubes. Modified carbon nanotubes were prepared by mixing pre-modified carbon nanotubes, 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine, and N,N-dimethylformamide at a mass ratio of 1:(0.2~0.4):(5~10) under a nitrogen atmosphere, stirring the mixture at 100~120℃ for 70~72h, cooling it to room temperature, centrifuging it, washing the precipitate 3~5 times with anhydrous ethanol, and drying it under vacuum at 50~60℃ for 10~12h.

[0017] As an optimization, the preparation steps of the aging-resistant rubber material in step (4) are as follows: Modified EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black, and paraffin oil are added to a two-roll mill in a mass ratio of 1:(0.1~0.2):(0.04~0.06):(0.01~0.02):(0.3~0.4):(0.15~0.25), and mixed at 50°C for 10~15 min. Then, 0.5 kg of modified EPDM rubber is added. Mix 0.01~0.02 times the amount of sulfur, 0.01~0.02 times the amount of accelerator TMTD (by weight of modified EPDM rubber), and 0.004~0.006 times the amount of accelerator M (by weight of modified EPDM rubber) for 5~10 minutes. After passing through a thin sheet 10 times, roll it out into sheets and let it stand at room temperature for 10~12 hours. Repeat the mixing and thinning process 3 times, then roll it out into sheets again. Place the sheets in a mold and hot press them at 150℃ and 10MPa for 20 minutes to obtain an aging-resistant rubber material.

[0018] As an optimization, the mass ratio of 4,4'-diaminodiphenylamine to 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride is 1:(1~1.2).

[0019] As an optimization, the reaction process of the antioxidant is as follows: .

[0020] As an optimization, the reaction process of the modified EPDM rubber is as follows: .

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are: In preparing the aging-resistant rubber material, this invention involves reacting 4,4'-diaminodiphenylamine with 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride to obtain an antioxidant; reacting maleic anhydride-grafted EPDM rubber with the antioxidant to obtain modified EPDM rubber; reacting carboxylated carbon nanotubes with 3-(diphenylphosphino)propylamine to obtain pre-modified carbon nanotubes; reacting the pre-modified carbon nanotubes with 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine to obtain modified carbon nanotubes; and mixing and hot-pressing the modified EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black, paraffin oil, sulfur, accelerator TMTD, and accelerator M to obtain the aging-resistant rubber material.

[0022] First, an antioxidant was prepared by reacting 4,4'-diaminodiphenylamine with 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride. The amino group on 4,4'-diaminodiphenylamine reacted with the acyl chloride group on 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride to generate an antioxidant containing a p-phenylenediamine antioxidant structure and a hindered phenolic structure. The p-phenylenediamine antioxidant structure and the hindered phenolic structure synergistically improved the aging resistance of the aging-resistant rubber material. Next, modified EPDM rubber was prepared by reacting maleic anhydride-grafted EPDM rubber with the antioxidant. The maleic anhydride groups on the grafted EPDM rubber underwent an amidation reaction with the amino group on the antioxidant, fixing the antioxidant onto the EPDM rubber. This resulted in a longer-lasting aging-resistant rubber material. Simultaneously, carboxyl groups were generated on the EPDM rubber, which bonded with the modified carbon nanotubes through electrostatic interactions and hydrogen bonds, improving the mechanical properties of the aging-resistant rubber material.

[0023] Secondly, carbon nanotubes possess excellent mechanical and electrical properties. Pre-modified carbon nanotubes are prepared by reacting carboxylated carbon nanotubes with 3-(diphenylphosphino)propylamine. The carboxyl groups on the carboxylated carbon nanotubes undergo an amidation reaction with the amino groups on the 3-(diphenylphosphino)propylamine, introducing phosphorus into the carbon nanotubes. Phosphorus can capture free radicals during combustion, thereby improving the flame retardant properties of the aging-resistant rubber material. The pre-modified carbon nanotubes undergo a quaternization reaction with 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine to generate modified carbon nanotubes containing quaternary phosphonate salt structures, improving the antistatic properties of the aging-resistant rubber material. Furthermore, the introduction of a large amount of nitrogen into the modified carbon nanotubes results in synergistic flame retardancy from nitrogen and phosphorus, further enhancing the flame retardant properties of the aging-resistant rubber material. Simultaneously, the modified carbon nanotubes and modified EPDM rubber are bonded through electrostatic interactions and hydrogen bonds, improving the mechanical properties of the aging-resistant rubber material. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1: A method for preparing an aging-resistant rubber material, comprising the following preparation steps: (1) Under a nitrogen atmosphere at 0°C, 4,4'-diaminodiphenylamine, triethylamine, and tetrahydrofuran were mixed evenly in a mass ratio of 1:0.35:5. A tetrahydrofuran solution of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride was added. The mixture was stirred and reacted at 50°C for 10 h. The tetrahydrofuran was removed by vacuum distillation. The mixture was washed three times with deionized water and dried under vacuum at 40°C for 10 h to obtain an antioxidant. The mass ratio of 4,4'-diaminodiphenylamine to 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride was 1:1. (2) Maleic anhydride-grafted EPDM rubber, antioxidant, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:0.12:10. The mixture was stirred and reacted at 35°C for 10 h. The N,N-dimethylformamide was removed by vacuum distillation. The mixture was washed three times with anhydrous ethanol and dried under vacuum at 40°C for 10 h to obtain modified EPDM rubber. (3) Carboxylated carbon nanotubes, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexylcarboimide and tetrahydrofuran were mixed evenly in a mass ratio of 1:1.5:0.1:10. The mixture was stirred at 20°C for 4 h, centrifuged, and the resulting precipitate was washed three times with anhydrous ethanol and dried under vacuum at 50°C for 10 h to obtain pre-modified carbon nanotubes. Under a nitrogen atmosphere, pre-modified carbon nanotubes, 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:0.2:5. The mixture was stirred at 100°C for 70 h, cooled to room temperature, centrifuged, and the resulting precipitate was washed three times with anhydrous ethanol and dried under vacuum at 50°C for 10 h to obtain modified carbon nanotubes. (4) Modified EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black and paraffin oil are added to a two-roll mill in a mass ratio of 1:0.1:0.04:0.01:0.3:0.15 and mixed at 50°C for 10 min. Then, sulfur (0.01 times the mass of modified EPDM rubber), accelerator TMTD (0.01 times the mass of modified EPDM rubber), and accelerator M (0.004 times the mass of modified EPDM rubber) are added and mixed for another 5 min. After passing through a thin roll 10 times, the roll is rolled out and placed at room temperature for 10 h. The roll is then passed through a thin roll 3 times and placed in a mold. The roll is then hot-pressed at 150°C and 10 MPa for 20 min to obtain an aging-resistant rubber material.

[0026] Example 2: A method for preparing an aging-resistant rubber material, comprising the following preparation steps: (1) Under a nitrogen atmosphere, at 2°C, 4,4'-diaminodiphenylamine, triethylamine, and tetrahydrofuran were mixed evenly at a mass ratio of 1:0.36):8. A tetrahydrofuran solution of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride was added. The mixture was stirred and reacted at 55°C for 11 h. The tetrahydrofuran was removed by vacuum distillation. The mixture was washed four times with deionized water and dried under vacuum at 45°C for 11 h to obtain an antioxidant. The mass ratio of 4,4'-diaminodiphenylamine to 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride was 1:1.1. (2) Maleic anhydride-grafted EPDM rubber, antioxidant, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:0.14:11. The mixture was stirred and reacted at 40°C for 11 h. The N,N-dimethylformamide was removed by vacuum distillation. The mixture was washed four times with anhydrous ethanol and dried under vacuum at 45°C for 11 h to obtain modified EPDM rubber. (3) Carboxylated carbon nanotubes, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexylcarboimide and tetrahydrofuran were mixed evenly in a mass ratio of 1:1.8:0.15:15. The mixture was stirred at 25°C for 5 h, centrifuged, and the resulting precipitate was washed four times with anhydrous ethanol and dried under vacuum at 55°C for 11 h to obtain pre-modified carbon nanotubes. Under a nitrogen atmosphere, pre-modified carbon nanotubes, 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:0.3:8. The mixture was stirred at 110°C for 71 h, cooled to room temperature, centrifuged, and the resulting precipitate was washed four times with anhydrous ethanol and dried under vacuum at 55°C for 11 h to obtain modified carbon nanotubes. (4) Modified EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black and paraffin oil are added to a two-roll mill in a mass ratio of 1:0.15:0.05:0.015:0.35:0.2 and mixed at 50°C for 12 min. Then, sulfur (0.015 times the mass of modified EPDM rubber), accelerator TMTD (0.015 times the mass of modified EPDM rubber), and accelerator M (0.005 times the mass of modified EPDM rubber) are added and mixed for another 8 min. After passing through a thin roll 10 times, the roll is rolled out and placed at room temperature for 11 h. The roll is then passed through a thin roll 3 times and placed in a mold. The roll is then hot-pressed at 150°C and 10 MPa for 20 min to obtain an aging-resistant rubber material.

[0027] Example 3: A method for preparing an aging-resistant rubber material, comprising the following preparation steps: (1) Under a nitrogen atmosphere, at 4°C, 4,4'-diaminodiphenylamine, triethylamine, and tetrahydrofuran were mixed evenly in a mass ratio of 1:0.37:10. A tetrahydrofuran solution of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride was added. The mixture was stirred and reacted at 60°C for 12 h. The tetrahydrofuran was removed by vacuum distillation. The mixture was washed 5 times with deionized water and dried under vacuum at 50°C for 12 h to obtain an antioxidant. The mass ratio of 4,4'-diaminodiphenylamine to 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride was 1:1.2. (2) Maleic anhydride-grafted EPDM rubber, antioxidant, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:0.16:12. The mixture was stirred and reacted at 45°C for 12 hours. N,N-dimethylformamide was removed by vacuum distillation. The mixture was washed five times with anhydrous ethanol and dried under vacuum at 50°C for 12 hours to obtain modified EPDM rubber. (3) Carboxylated carbon nanotubes, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexylcarboimide, and tetrahydrofuran were mixed evenly in a mass ratio of 1:2:0.2:20. The mixture was stirred at 30°C for 6 hours, centrifuged, and the resulting precipitate was washed five times with anhydrous ethanol and dried under vacuum at 60°C for 12 hours to obtain pre-modified carbon nanotubes. Under a nitrogen atmosphere, pre-modified carbon nanotubes, 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine, and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:0.4:10. The mixture was stirred at 120°C for 72 hours, cooled to room temperature, centrifuged, and the resulting precipitate was washed five times with anhydrous ethanol and dried under vacuum at 60°C for 12 hours to obtain modified carbon nanotubes. (4) Modified EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black and paraffin oil are added to a two-roll mill in a mass ratio of 1:0.2:0.06:0.02:0.4:0.25 and mixed at 50°C for 15 min. Then, sulfur (0.02 times the mass of modified EPDM rubber), accelerator TMTD (0.02 times the mass of modified EPDM rubber), and accelerator M (0.006 times the mass of modified EPDM rubber) are added and mixed for another 10 min. After passing through a thin roll 10 times, the roll is rolled out and placed at room temperature for 12 h. The roll is then passed through a thin roll 3 times and placed in a mold. The roll is then hot-pressed at 150°C and 10 MPa for 20 min to obtain an aging-resistant rubber material.

[0028] Comparative Example 1 The difference between the preparation method of the aging-resistant rubber material in Comparative Example 1 and Example 2 is that step (1) is omitted, and step (2) is modified as follows: maleic anhydride-grafted EPDM rubber, 4,4'-diaminodiphenylamine, and N,N-dimethylformamide are mixed evenly at a mass ratio of 1:0.14:11, stirred and reacted at 40°C for 11 h, N,N-dimethylformamide is removed by vacuum distillation, washed four times with anhydrous ethanol, and dried under vacuum at 45°C for 11 h to obtain modified EPDM rubber. The remaining steps are the same as in Example 2.

[0029] Comparative Example 2 The preparation method of the aging-resistant rubber material in Comparative Example 2 differs from that in Example 2 in that steps (1) and (2) are omitted, and step (4) is modified as follows: maleic anhydride-grafted EPDM rubber, modified carbon nanotubes, zinc oxide, stearic acid, carbon black, and paraffin oil are added to a two-roll mill in a mass ratio of 1:0.15:0.05:0.015:0.35:0.2 and mixed at 50°C for 12 minutes. Then, sulfur (0.015 times the mass of modified EPDM rubber), accelerator TMTD (0.015 times the mass of modified EPDM rubber), and accelerator M (0.005 times the mass of modified EPDM rubber) are added, and the mixture is mixed for another 8 minutes. After passing through a thin roll 10 times, the mixture is rolled into sheets and left at room temperature for 11 hours. After passing through a thin roll 3 times again, the sheets are placed in a mold and hot-pressed at 150°C and 10 MPa for 20 minutes to obtain the aging-resistant rubber material. The remaining steps are the same as in Example 2.

[0030] Comparative Example 3 The difference between the preparation method of the aging-resistant rubber material in Comparative Example 3 and Example 2 lies in step (3). Step (3) is modified as follows: Carboxylated carbon nanotubes, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexylcarboimide, and tetrahydrofuran are mixed evenly in a mass ratio of 1:1.8:0.15:15, stirred and reacted at 25°C for 5 hours, centrifuged, and the resulting precipitate was washed four times with anhydrous ethanol and dried under vacuum at 55°C for 11 hours to obtain modified carbon nanotubes. The remaining steps are the same as in Example 2.

[0031] Comparative Example 4 The difference between the preparation method of the aging-resistant rubber material in Comparative Example 4 and Example 2 is that step (3) is omitted, and step (4) is modified as follows: Modified EPDM rubber, carboxylated carbon nanotubes, zinc oxide, stearic acid, carbon black, and paraffin oil are added to a two-roll mill in a mass ratio of 1:0.15:0.05:0.015:0.35:0.2 and mixed at 50°C for 12 minutes. Then, sulfur (0.015 times the mass of modified EPDM rubber), accelerator TMTD (0.015 times the mass of modified EPDM rubber), and accelerator M (0.005 times the mass of modified EPDM rubber) are added, and the mixture is mixed for another 8 minutes. After passing through a thin roll 10 times, the mixture is rolled into sheets and left at room temperature for 11 hours. After passing through a thin roll 3 times, the sheets are placed in a mold and hot-pressed at 150°C and 10 MPa for 20 minutes to obtain the aging-resistant rubber material. The remaining steps are the same as in Example 2.

[0032] Comparative Example 5 The preparation method of the aging-resistant rubber material in Comparative Example 5 differs from that in Example 2 in that step (3) is omitted, and step (4) is modified as follows: Modified EPDM rubber, zinc oxide, stearic acid, carbon black, and paraffin oil are added to a two-roll mill in a mass ratio of 1:0.05:0.015:0.35:0.2 and mixed at 50°C for 12 minutes. Then, sulfur (0.015 times the mass of modified EPDM rubber), accelerator TMTD (0.015 times the mass of modified EPDM rubber), and accelerator M (0.005 times the mass of modified EPDM rubber) are added, and the mixture is mixed for another 8 minutes. After passing through a thin roll 10 times, the mixture is rolled into sheets and left at room temperature for 11 hours. After passing through a thin roll 3 times again, the sheets are placed in a mold and hot-pressed at 150°C and 10 MPa for 20 minutes to obtain the aging-resistant rubber material. The remaining steps are the same as in Example 2.

[0033] Test Example 1 Aging resistance and mechanical property testing: Mechanical property testing: The aging-resistant rubber materials prepared in each example and comparative example were cut into dumbbell-shaped strips and subjected to tensile strength testing in accordance with GB / T528-2009 on a universal testing machine. The tensile rate was 500 mm / min, and each group of samples was repeated five times. The average value was calculated and recorded as M.

[0034] Aging resistance test: The aging-resistant rubber materials prepared in each example and comparative example were cut into dumbbell-shaped strips and exposed to a 60Co γ-ray source. The cumulative irradiation was 200kGy at a dose rate of 7Gy / min. The irradiation test was carried out in an air atmosphere at room temperature. After the irradiation was completed, the tensile strength was measured again and recorded as N. The performance degradation rate was calculated as 1-N / M×100%.

[0035] The results are shown in Table 1.

[0036] Table 1

[0037] A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-5 in Table 1 shows that the aging-resistant rubber material prepared by the present invention has good mechanical properties and aging resistance.

[0038] By comparison, the tensile strength of Examples 1-3 is greater than that of Comparative Examples 2-5, indicating that carbon nanotubes have good mechanical properties. After modification, they are combined with modified EPDM rubber through electrostatic interaction, hydrogen bonding and other means, which improves the mechanical properties of the aging-resistant rubber material.

[0039] By comparison, the performance degradation rate of Examples 1-3 was less than that of Comparative Examples 1-2, indicating that the amino group on 4,4'-diaminodiphenylamine reacts with the acyl chloride group on 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride to generate an anti-aging agent containing a p-phenylenediamine antioxidant structure and a hindered phenolic structure. The p-phenylenediamine antioxidant structure and the hindered phenol work synergistically to improve the aging resistance of the aging-resistant rubber material.

[0040] Test Example 2 Flame retardant performance test: The aging-resistant rubber materials obtained from each embodiment and comparative example were made into 100mm×6.5mm×3mm specimens, and the limiting oxygen index was tested using an HC-2 oxygen index meter according to ASTM D2863 standard.

[0041] The results are shown in Table 2.

[0042] Table 2

[0043] A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 2 reveals that the aging-resistant rubber material prepared by this invention has good flame-retardant properties.

[0044] By comparison, the limiting oxygen index of Examples 1-3 was greater than that of Comparative Examples 3-5, indicating that the carboxyl groups on the carboxylated carbon nanotubes underwent an amidation reaction with the amino groups on 3-(diphenylphosphino)propylamine, introducing phosphorus into the carbon nanotubes. Phosphorus can capture free radicals during combustion, thereby improving the flame retardant properties of the aging-resistant rubber material. Furthermore, the pre-modified carbon nanotubes underwent a quaternization reaction with 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine, introducing a large amount of nitrogen into the modified carbon nanotubes. The synergistic flame retardancy of N and P further improved the flame retardant properties of the aging-resistant rubber material.

[0045] Test Example 3 Antistatic performance test: The aging-resistant rubber materials prepared in each embodiment and comparative example were made into strips of equal size and 1 mm thickness. The volume resistivity was tested using an EST121 digital ultra-high resistance tester according to ASTM D257 standard.

[0046] The results are shown in Table 3.

[0047] Table 3

[0048] A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 3 reveals that the aging-resistant rubber material prepared by this invention has good antistatic properties.

[0049] By comparison, the volume resistivity of Examples 1-3 is less than that of Comparative Examples 3-5, indicating that carbon nanotubes have good electrical properties. The pre-modified carbon nanotubes undergo a quaternization reaction with 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine to generate modified carbon nanotubes containing quaternary phosphonium salt structures, which improves the antistatic properties of aging-resistant rubber materials.

[0050] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An aging resistant rubber material, characterized by, The anti-aging rubber material is prepared by mixing modified ethylene-propylene-diene rubber, modified carbon nanotube, zinc oxide, stearic acid, carbon black, paraffin oil, sulfur, accelerator TMTD, accelerator M, hot pressing; The modified ethylene-propylene-diene rubber is prepared by reacting maleic anhydride grafted ethylene-propylene-diene rubber with an antioxidant; The antioxidant is prepared by reacting 4,4'-diaminodiphenylamine with 3,5-bis(tert-butyl)-4-hydroxybenzene propionyl chloride; The modified carbon nanotube is prepared by reacting carboxylated carbon nanotube with 3-(diphenylphosphino)propylamine to obtain pre-modified carbon nanotube, and then reacting the pre-modified carbon nanotube with 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine.

2. The weatherable rubber material of claim 1, wherein, The carboxylated carbon nanotube has a length of 0.5-2 μm and a diameter of 20-30 nm.

3. The weatherable rubber material of claim 1, wherein, The maleic anhydride grafted ethylene-propylene-diene rubber has a grafting rate of 1.5%.

4. A method for producing an aging-resistant rubber material, characterized by, The preparation comprises the following steps: (1) Under a nitrogen atmosphere, 4,4'-diaminodiphenylamine, triethylamine and tetrahydrofuran are uniformly mixed at 0-4°C, and a tetrahydrofuran solution of 3,5-bis(tert-butyl)-4-hydroxybenzene propionyl chloride is added. Stirring is performed at 50-60°C for 10-12 hours. Vacuum distillation, washing and drying are performed to obtain the antioxidant. (2) The maleic anhydride grafted ethylene-propylene-diene rubber, the antioxidant and N,N-dimethylformamide are uniformly mixed, and stirring is performed at 35-45°C for 10-12 hours. Vacuum distillation, washing and drying are performed to obtain the modified ethylene-propylene-diene rubber. (3) The carboxylated carbon nanotube, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexylcarbodiimide and tetrahydrofuran are uniformly mixed, and stirring is performed at 20-30°C for 4-6 hours. Centrifugal separation, washing and drying are performed to obtain the pre-modified carbon nanotube. Under a nitrogen atmosphere, the pre-modified carbon nanotube, 2-(3-chloropropyl)-4,6-dimethyl-1,3,5-triazine and N,N-dimethylformamide are uniformly mixed, and stirring is performed at 100-120°C for 70-72 hours. Cooling to room temperature, centrifugal separation, washing and drying are performed to obtain the modified carbon nanotube. (4) The modified ethylene-propylene-diene rubber, the modified carbon nanotube, zinc oxide, stearic acid, carbon black and paraffin oil are added to an open mill, and mixing is performed at 50°C for 10-15 minutes. Sulfur, accelerator TMTD and accelerator M are added, and mixing is continuously performed for 5-10 minutes. After 10 times of thin passing, the rubber is rolled and sheeted. The rubber is placed at room temperature for 10-12 hours. The rubber is returned to the mill, thin passed for 3 times and sheeted. The rubber is placed in a mold, hot pressed at 150°C and 10 MPa for 20 minutes to obtain the anti-aging rubber material.

5. The method of claim 4, wherein the antioxidant is added in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the rubber component. In step (1), the preparation of the antioxidant is performed as follows: under a nitrogen atmosphere, 4,4'-diaminodiphenylamine, triethylamine and tetrahydrofuran are uniformly mixed at 0-4°C in a mass ratio of 1:(0.35-0.37):(5-10). A tetrahydrofuran solution of 3,5-bis(tert-butyl)-4-hydroxybenzene propionyl chloride is added. Stirring is performed at 50-60°C for 10-12 hours. Tetrahydrofuran is removed by vacuum distillation. Deionized water is used for washing 3-5 times. Vacuum drying is performed at 40-50°C for 10-12 hours to obtain the antioxidant.

6. The method of claim 4, wherein the antioxidant is selected from the group consisting of phenolic antioxidants, aminic antioxidants, phosphorous antioxidants, thio antioxidants, and mixtures thereof. The preparation step of the modified EPDM rubber in step (2) is as follows: maleic anhydride grafted EPDM rubber, antioxidant, N,N-dimethylformamide are uniformly mixed in a mass ratio of 1:(0.12-0.16):(10-12), stirred and reacted at 35-45 DEG C for 10-12 h, N,N-dimethylformamide is removed by distillation under reduced pressure, washed with anhydrous ethanol for 3-5 times, and vacuum dried at 40-50 DEG C for 10-12 h to obtain the modified EPDM rubber.

7. The method of claim 4, wherein the antioxidant is selected from the group consisting of phenolic antioxidants, aminic antioxidants, phosphorous antioxidants, thio antioxidants, and mixtures thereof. The preparation step of the modified carbon nanotube in step (3) is as follows: carboxylated carbon nanotube, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexyl carbodiimide, tetrahydrofuran are uniformly mixed in a mass ratio of 1:(1.5-2):(0.1-0.2):(10-20), stirred and reacted at 20-30 DEG C for 4-6 h, centrifuged, the obtained precipitate is washed with anhydrous ethanol for 3-5 times, and vacuum dried at 50-60 DEG C for 10-12 h to obtain the pre-modified carbon nanotube. The preparation step of the modified carbon nanotube in step (3) is as follows: carboxylated carbon nanotube, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexyl carbodiimide, tetrahydrofuran are uniformly mixed in a mass ratio of 1:(1.5-2):(0.1-0.2):(10-20), stirred and reacted at 20-30 DEG C for 4-6 h, centrifuged, the obtained precipitate is washed with anhydrous ethanol for 3-5 times, and vacuum dried at 50-60 DEG C for 10-12 h to obtain the pre-modified carbon nanotube.

8. The method of claim 4, wherein the antioxidant is selected from the group consisting of phenolic antioxidants, aminic antioxidants, phosphorous antioxidants, thio antioxidants, and mixtures thereof. The preparation step of the modified carbon nanotube in step (3) is as follows: carboxylated carbon nanotube, 3-(diphenylphosphino)propylamine, N,N'-dicyclohexyl carbodiimide, tetrahydrofuran are uniformly mixed in a mass ratio of 1:(1.5-2):(0.1-0.2):(10-20), stirred and reacted at 20-30 DEG C for 4-6 h, centrifuged, the obtained precipitate is washed with anhydrous ethanol for 3-5 times, and vacuum dried at 50-60 DEG C for 10-12 h to obtain the pre-modified carbon nanotube.

9. The method of claim 5, wherein the antioxidant is selected from the group consisting of phenolic antioxidants, aminic antioxidants, phosphorous antioxidants, thio antioxidants, and mixtures thereof. The preparation step of the aging-resistant rubber material in step (4) is as follows: the modified EPDM rubber, the modified carbon nanotube, zinc oxide, stearic acid, carbon black, paraffin oil are added into an open mill in a mass ratio of 1:(0.1-0.2):(0.04-0.06):(0.01-0.02):(0.3-0.4):(0.15-0.25), mixed at 50 DEG C for 10-15 min, sulfur in an amount of 0.01-0.02 times of the modified EPDM rubber, accelerator TMTD in an amount of 0.01-0.02 times of the modified EPDM rubber, and accelerator M in an amount of 0.004-0.006 times of the modified EPDM rubber are added, and mixed for another 5-10 min, then thin passed for 10 times, rolled and sheeted, placed at room temperature for 10-12 h, re-mixed and thin passed for 3 times, sheeted, and placed in a mold, hot pressed at 150 DEG C and 10 MPa for 20 min to obtain the aging-resistant rubber material. The mass ratio of the 4,4'-diaminodiphenylamine and 3,5-bis(tert-butyl)-4-hydroxybenzaldehyde chloride is 1:(1-1.2).

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