Anti-aging sealing material and preparation method thereof

Abstract

The invention relates to the technical field of rubber materials, and discloses an anti-aging sealing material and a preparation method thereof. The anti-aging sealing material prepared by the invention is prepared by taking the nitrile rubber and the chloroprene rubber as main rubber matrixes and then adding the plasticizer, the composite anti-aging agent, the lubricant, the zinc oxide, the silane coupling agent, the sulfur and the vulcanization accelerator, and has excellent anti-aging performance, tensile property and hardness; the method can be widely applied to the fields of automobile manufacturing, electronic devices and the like.

Description

Technical Field

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

[0002] Rubber seals are essential components in industrial equipment, transportation, aerospace, and other fields, with their core function being to prevent media leakage and the intrusion of external contaminants. Nitrile rubber (NBR) is one of the two most commonly used elastomer materials for manufacturing seals due to its excellent oil resistance, while chloroprene rubber (CR) is another due to its good weather resistance, flame retardancy, and moderate oil resistance.

[0003] However, during long-term use, rubber materials are inevitably exposed to complex environments such as heat, oxygen, ozone, light, mechanical stress, and media corrosion, leading to aging. Aging is mainly manifested as molecular chain degradation or excessive cross-linking, which in turn causes the material to harden, become brittle, soften, become sticky, crack, and experience a significant decrease in mechanical properties (such as tensile strength, elongation, and elasticity), ultimately leading to sealing failure, equipment malfunction, energy waste, and even safety accidents. Therefore, developing a sealing material with excellent aging resistance to meet the growing demand for long-term, reliable, and safe operation of equipment has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an aging-resistant sealing material and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An aging-resistant sealing material comprises the following raw materials in parts by weight: 50-70 parts of nitrile rubber, 15-25 parts of chloroprene rubber, 1-3 parts of plasticizer, 8-15 parts of zinc oxide, 2-4 parts of silane coupling agent, 2-4 parts of composite antioxidant, 1.5-2.5 parts of sulfur, 0.3-1 part of vulcanization accelerator, and 1-3 parts of lubricant;

[0007] Furthermore, the plasticizer is one of dioctyl phthalate or epoxidized soybean oil;

[0008] Furthermore, the silane coupling agent is one of KH550, KH560, or KH570;

[0009] Furthermore, the vulcanization accelerator is one of accelerator DM or accelerator TMTD;

[0010] Furthermore, the lubricant is one of zinc stearate or polyethylene wax;

[0011] The composite anti-aging agent is prepared by the following steps:

[0012] Step A1: Under nitrogen protection, 2-chloroethylamine hydrochloride is thoroughly mixed in ethanol, then anhydrous sodium carbonate is added and stirred for 30 min. The mixture is heated to 80 °C and refluxed, then 4,4′-diaminodiphenylamine is added. The mixture is stirred under reflux for 4-6 h and cooled to room temperature. The mixture is then distilled under reduced pressure to obtain the terminal aminodiphenylamine product.

[0013] Further, in step A1, the ratio of 2-chloroethylamine hydrochloride, ethanol, anhydrous sodium carbonate, and 4,4′-diaminodiphenylamine is 0.01-0.03 mol: 100 mL: 0.016-0.048 mol: 0.005-0.015 mol;

[0014] Step A2: Dissolve maleic anhydride in DMF (N,N-dimethylformamide), and label it reaction solution 1; mix the terminal amino diphenylamine product in DMF, and label it reaction solution 2; slowly add reaction solution 2 dropwise to reaction solution 1, react at room temperature for 1.5-3.5 h, then add anhydrous sodium acetate and hydroquinone and stir for 15-30 min, then add acetic anhydride, heat to 50 °C and stir for 2-3 h, cool, pour into crushed ice and let stand for 5 min, filter, wash, dry and recrystallize to obtain the imide-based diphenylamine product;

[0015] Furthermore, in step A2, the molar ratio of maleic anhydride to the terminal aminodiphenylamine product is 2:1;

[0016] Further, in step A2, the molar ratio of anhydrous sodium acetate, hydroquinone, acetic anhydride, and maleic anhydride is 0.23-0.25:0.15-0.18:1.5-1.7:1;

[0017] Step A3: Under nitrogen protection, the imide-based diphenylamine product and DMF are mixed evenly, then triethylamine is added and stirred evenly, then methylimidazolium product is added and stirred evenly, and the temperature is raised to 85℃ and refluxed for 3-5 hours. After cooling to room temperature, the product is purified by rotary evaporation, column chromatography, secondary rotary evaporation, and vacuum drying to obtain the composite antioxidant.

[0018] Further, in step A3, the ratio of the imide diphenylamine product, DMF, triethylamine, and methylimidazole product is 0.01-0.03 mol: 50 mL: 0.012-0.035 mol: 0.01-0.03 mol;

[0019] Furthermore, the methylimidazole product described in step A3 is specifically prepared by the following steps:

[0020] 4-Methyl-5-hydroxymethylimidazolium hydrochloride, sodium hydroxide, and DMF were mixed and stirred until homogeneous. The precipitate was removed by filtration, and DMF was removed by vacuum distillation. The product was washed and collected. 3-chloropropionic acid and toluene were added to the product. The mixture was stirred in an ice-water bath while 98 wt% concentrated sulfuric acid was added dropwise. The reaction was maintained in an ice-water bath for 2.5-3.5 h. The mixture was then stirred at room temperature for 12-18 h. The mixture was then distilled under vacuum, and saturated sodium bicarbonate solution was added. The mixture was filtered under vacuum and dried to obtain the methylimidazolium product.

[0021] Furthermore, the ratio of 4-methyl-5-hydroxymethylimidazolium hydrochloride, sodium hydroxide, DMF, 3-chloropropionic acid, toluene, concentrated sulfuric acid, and saturated sodium bicarbonate solution in the methylimidazolium product is 0.02-0.03 mol : 0.08-0.12 g : 100 mL : 0.01 mol : 50 mL : 3-4 mL : 200 mL.

[0022] A method for preparing an aging-resistant sealing material includes the following steps:

[0023] Step S1: Weigh the raw materials according to the weight parts, set the starting temperature of the internal mixer to 50-60℃, add zinc oxide, silane coupling agent, composite antioxidant and lubricant into the internal mixer and stir evenly, then add nitrile rubber, chloroprene rubber, plasticizer, sulfur and vulcanization accelerator in sequence and internally mix at 80-90℃ for 5-10 minutes, then raise the temperature to 100-110℃ and stir for 50-70 minutes, and then let it stand and age for 5 hours to obtain the mixture;

[0024] Step S2: The mixture is fed into a twin-screw extruder, melt-extruded, granulated, dried, and then extruded to obtain an aging-resistant sealing material.

[0025] Furthermore, in step S2, the extrusion temperature of the twin-screw extruder is 175-195℃, and the rotation speed is 200 rpm / min.

[0026] The beneficial effects of this invention are:

[0027] The aging-resistant sealing material prepared by this invention is made of nitrile rubber and chloroprene rubber as the main rubber matrix, and then plasticizers, composite antioxidants, lubricants, zinc oxide, silane coupling agents, sulfur and vulcanization accelerators are added. This material has excellent aging resistance, tensile properties and hardness, and can be widely used in automobile manufacturing, electronic devices and other fields.

[0028] The composite antioxidant introduced in the aging-resistant sealing material of this invention differs from the single, small-molecule antioxidants added to traditional aging-resistant sealing materials. This composite antioxidant imparts superior aging resistance to the sealing material within the matrix. The composite antioxidant utilizes the synergistic effect between diphenylamine, imidazole, and maleimide structures to exert its anti-aging effect. Specifically, the NH bond in the diphenylamine structure has low bond energy and is easily homolytically cleaved. The provided hydrogen atoms can rapidly capture and eliminate these highly reactive free radicals, converting them into stable, inert substances, thereby interrupting the chain oxidation reaction. Meanwhile, the nitrogen atom on the imidazole ring possesses a lone pair of electrons, which can react with catalytically active metal ions on the surface of metal parts. The complex forms a stable complex that encapsulates the metal ions, preventing them from contacting rubber hydrocarbons and oxygen, thus completely eliminating their catalytic activity. This is crucial for sealing materials that may come into contact with metal parts or metalworking oils. The introduction of the maleimide structure not only improves the heat resistance of the material but also utilizes the high electrophilicity of the double bonds that have not participated in the vulcanization reaction to undergo an addition reaction with the carbon center free radicals (R·) generated during rubber aging, directly eliminating the free radicals and preventing them from reacting with oxygen to generate peroxy free radicals. Furthermore, some of the double bond structures can participate in the rubber vulcanization process, anchoring the composite antioxidant to the rubber molecular chain, which can effectively reduce the decline in antioxidant effect caused by migration. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1: The methylimidazole product was prepared by the following steps:

[0031] 0.02 mol of 4-methyl-5-hydroxymethylimidazolium hydrochloride, 0.08 g of sodium hydroxide, and 100 mL of DMF were mixed and stirred until homogeneous. The precipitate was removed by filtration, and DMF was removed by vacuum distillation. The product was washed and collected. 0.01 mol of 3-chloropropionic acid and 50 mL of toluene were added to the product. The mixture was stirred in an ice-water bath, and 3 mL of 98 wt% concentrated sulfuric acid was added dropwise while stirring. The reaction was maintained in an ice-water bath for 2.5 h, and then stirred at room temperature for 12 h. The mixture was then distilled under reduced pressure, and 200 mL of saturated sodium bicarbonate solution was added. The mixture was filtered under reduced pressure and dried to obtain the methylimidazolium product.

[0032] The composite anti-aging agent is prepared by the following steps:

[0033] Step A1: Under nitrogen protection, 0.01 mol of 2-chloroethylamine hydrochloride was thoroughly mixed in 100 mL of ethanol, and then 0.016 mol of anhydrous sodium carbonate was added and stirred for 30 min. The mixture was heated to 80 °C and refluxed, and then 0.005 mol of 4,4′-diaminodiphenylamine was added. The mixture was stirred under reflux for 4 h and cooled to room temperature. The product was then distilled under reduced pressure to obtain the terminal aminodiphenylamine product.

[0034] Step A2: Dissolve 0.2 mol of maleic anhydride in 100 mL of DMF, and label it as reaction solution 1; mix 0.1 mol of the terminal aminodiphenylamine product in 100 mL of DMF, and label it as reaction solution 2; slowly add reaction solution 2 dropwise to reaction solution 1, react at room temperature for 1.5 h, then add 0.046 mol of anhydrous sodium acetate and 0.03 mol of hydroquinone and stir for 15 min, then add 0.3 mol of acetic anhydride, heat to 50 °C and stir for 2 h, cool, pour into crushed ice and let stand for 5 min, filter, wash, dry and recrystallize to obtain the imide-based diphenylamine product;

[0035] Step A3: Under nitrogen protection, mix 0.01 mol of imide-based diphenylamine product with 50 mL of DMF, then add 0.012 mol of triethylamine and stir thoroughly. Next, add 0.01 mol of methylimidazolium product and stir thoroughly. Heat to 85°C and reflux for 3 hours. Cool to room temperature, purify by rotary evaporation and column chromatography, perform secondary rotary evaporation, and vacuum drying to obtain the composite antioxidant.

[0036] Example 2: The methylimidazole product was prepared by the following steps:

[0037] 0.025 mol of 4-methyl-5-hydroxymethylimidazolium hydrochloride, 0.1 g of sodium hydroxide, and 100 mL of DMF were mixed and stirred until homogeneous. The precipitate was removed by filtration, and DMF was removed by vacuum distillation. The product was washed and collected. 0.01 mol of 3-chloropropionic acid and 50 mL of toluene were added to the product. The mixture was stirred in an ice-water bath, and 3.5 mL of 98 wt% concentrated sulfuric acid was added dropwise while stirring. The reaction was maintained in an ice-water bath for 3 h, and then stirred at room temperature for 15 h. The mixture was then distilled under reduced pressure, and 200 mL of saturated sodium bicarbonate solution was added. The mixture was filtered under reduced pressure and dried to obtain the methylimidazolium product.

[0038] The composite anti-aging agent is prepared by the following steps:

[0039] Step A1: Under nitrogen protection, 0.02 mol of 2-chloroethylamine hydrochloride was thoroughly mixed in 100 mL of ethanol, then 0.032 mol of anhydrous sodium carbonate was added and stirred for 30 min. The mixture was heated to 80 °C and refluxed, then 0.01 mol of 4,4′-diaminodiphenylamine was added. The mixture was stirred under reflux for 5 h and cooled to room temperature. The product was then distilled under reduced pressure to obtain the terminal aminodiphenylamine product.

[0040] Step A2: Dissolve 0.2 mol of maleic anhydride in 100 mL of DMF, and label this as reaction solution 1; mix 0.1 mol of the terminal aminodiphenylamine product in 100 mL of DMF, and label this as reaction solution 2; slowly add reaction solution 2 dropwise to reaction solution 1, react at room temperature for 1.5-3.5 h, then add 0.048 mol of anhydrous sodium acetate and 0.033 mol of hydroquinone and stir for 25 min, then add 0.32 mol of acetic anhydride, heat to 50 °C and stir for 2.5 h, cool, pour into crushed ice and let stand for 5 min, filter, wash, dry and recrystallize to obtain the imide-based diphenylamine product;

[0041] Step A3: Under nitrogen protection, mix 0.02 mol of imide-based diphenylamine product with 50 mL of DMF, then add 0.025 mol of triethylamine and stir thoroughly. Next, add 0.02 mol of methylimidazolium product and stir thoroughly. Heat to 85°C and reflux for 4 hours. Cool to room temperature, purify by rotary evaporation and column chromatography, perform secondary rotary evaporation, and vacuum drying to obtain the composite antioxidant.

[0042] Example 3: The methylimidazole product was prepared by the following steps:

[0043] 0.03 mol of 4-methyl-5-hydroxymethylimidazolium hydrochloride, 0.12 g of sodium hydroxide, and 100 mL of DMF were mixed and stirred until homogeneous. The precipitate was removed by filtration, and DMF was removed by vacuum distillation. The product was washed and collected. 0.01 mol of 3-chloropropionic acid and 50 mL of toluene were added to the product. The mixture was stirred in an ice-water bath, and 4 mL of 98 wt% concentrated sulfuric acid was added dropwise while stirring. The reaction was maintained in an ice-water bath for 3.5 h, and then stirred at room temperature for 18 h. The mixture was then distilled under reduced pressure, and 200 mL of saturated sodium bicarbonate solution was added. The mixture was filtered under reduced pressure and dried to obtain the methylimidazolium product.

[0044] The composite anti-aging agent is prepared by the following steps:

[0045] Step A1: Under nitrogen protection, 0.03 mol of 2-chloroethylamine hydrochloride was thoroughly mixed in 100 mL of ethanol, and then 0.048 mol of anhydrous sodium carbonate was added and stirred for 30 min. The mixture was heated to 80 °C and refluxed, and then 0.015 mol of 4,4′-diaminodiphenylamine was added. The mixture was stirred under reflux for 6 h and cooled to room temperature. The product was then distilled under reduced pressure to obtain the terminal aminodiphenylamine product.

[0046] Step A2: Dissolve 0.2 mol of maleic anhydride in 100 mL of DMF, and label this as reaction solution 1; mix 0.1 mol of the terminal aminodiphenylamine product in 100 mL of DMF, and label this as reaction solution 2; slowly add reaction solution 2 dropwise to reaction solution 1, react at room temperature for 3.5 h, then add 0.05 mol of anhydrous sodium acetate and 0.036 mol of hydroquinone and stir for 30 min, then add 0.34 mol of acetic anhydride, heat to 50 °C and stir for 3 h, cool, pour into crushed ice and let stand for 5 min, filter, wash, dry and recrystallize to obtain the imide-based diphenylamine product;

[0047] Step A3: Under nitrogen protection, mix 0.03 mol of imide-based diphenylamine product with 50 mL of DMF, then add 0.035 mol of triethylamine and stir thoroughly. Next, add 0.03 mol of methylimidazolium product and stir thoroughly. Heat to 85 °C and reflux for 5 h. Cool to room temperature, purify by rotary evaporation and column chromatography, perform secondary rotary evaporation, and vacuum drying to obtain the composite antioxidant.

[0048] Example 4: A method for preparing an aging-resistant sealing material includes the following steps:

[0049] 50 parts of nitrile rubber, 15 parts of chloroprene rubber, 1 part of dioctyl phthalate, 8 parts of zinc oxide, 2 parts of silane coupling agent KH550, 2 parts of the composite antioxidant prepared in Example 1, 1.5 parts of sulfur, 0.3 parts of accelerator DM, and 1 part of zinc stearate.

[0050] Step S1: Weigh the raw materials according to the weight parts, set the starting temperature of the internal mixer to 50°C, add zinc oxide, silane coupling agent KH550, the composite antioxidant prepared in Example 1 and zinc stearate into the internal mixer and stir evenly, then add nitrile rubber, chloroprene rubber, dioctyl phthalate, sulfur and accelerator DM in sequence and internally mix at 80°C for 5 minutes, then raise the temperature to 100°C and stir for 50 minutes, and then let it stand and age for 5 hours to obtain the mixture;

[0051] Step S2: The mixture is fed into a twin-screw extruder, melt-extruded, granulated, dried, and then extruded to obtain an aging-resistant sealing material. The extrusion temperature of the twin-screw extruder is 175℃ and the speed is 200rpm / min.

[0052] Example 5: A method for preparing an aging-resistant sealing material includes the following steps:

[0053] 60 parts of nitrile rubber, 20 parts of chloroprene rubber, 2 parts of epoxidized soybean oil, 12 parts of zinc oxide, 3 parts of silane coupling agent KH560, 3 parts of the composite antioxidant prepared in Example 2, 2 parts of sulfur, 0.6 parts of accelerator TMTD, and 2 parts of polyethylene wax.

[0054] Step S1: Weigh the raw materials according to the weight parts, set the starting temperature of the internal mixer to 55°C, add zinc oxide, silane coupling agent KH560, the composite antioxidant prepared in Example 2 and polyethylene wax into the internal mixer and stir evenly, then add nitrile rubber, chloroprene rubber, epoxidized soybean oil, sulfur and accelerator TMTD in sequence and internally mix at 85°C for 8 minutes, then raise the temperature to 105°C and stir for 60 minutes, and then let it stand and age for 5 hours to obtain the mixture.

[0055] Step S2: The mixture is fed into a twin-screw extruder, melt-extruded, granulated, dried, and then extruded to obtain an aging-resistant sealing material. The extrusion temperature of the twin-screw extruder is 185℃ and the speed is 200rpm / min.

[0056] Example 6: A method for preparing an aging-resistant sealing material includes the following steps:

[0057] 70 parts of nitrile rubber, 25 parts of chloroprene rubber, 3 parts of dioctyl phthalate, 15 parts of zinc oxide, 4 parts of silane coupling agent KH570, 4 parts of the composite antioxidant prepared in Example 3, 2.5 parts of sulfur, 1 part of accelerator DM, and 3 parts of zinc stearate.

[0058] Step S1: Weigh the raw materials according to the weight parts, set the starting temperature of the internal mixer to 60°C, add zinc oxide, silane coupling agent KH570, the composite antioxidant prepared in Example 3 and zinc stearate into the internal mixer and stir evenly, then add nitrile rubber, chloroprene rubber, dioctyl phthalate, sulfur and accelerator DM in sequence and internally mix at 90°C for 10 min, then raise the temperature to 110°C and stir for 70 min, and then let it stand and age for 5 h to obtain the mixture;

[0059] Step S2: The mixture is fed into a twin-screw extruder, melt-extruded, granulated, dried, and then extruded to obtain an aging-resistant sealing material. The extrusion temperature of the twin-screw extruder is 195℃ and the speed is 200rpm / min.

[0060] Comparative Example 1: This comparative example is an aging-resistant sealing material. The difference between this example and Example 6 is that IPPD is used instead of the composite antioxidant prepared in Example 3. All other aspects are the same.

[0061] Comparative Example 2: This comparative example is an aging-resistant sealing material. The difference between this example and Example 6 is that antioxidant 264 is used instead of the composite antioxidant prepared in Example 3. All other aspects are the same.

[0062] Comparative Example 3: This comparative example is an aging-resistant sealing material. The difference between this example and Example 6 is that antioxidant 445 is used instead of the composite antioxidant prepared in Example 3. All other aspects are the same.

[0063] Comparative Example 4: This comparative example is an aging-resistant sealing material. The difference between this example and Example 6 is that the composite antioxidant prepared in Example 3 was not added. All other aspects are the same.

[0064] The aging resistance properties of the aging-resistant sealing materials prepared in Examples 4-6 and Comparative Examples 1-4 were tested:

[0065] Hot air aging performance test: In accordance with GB / T 3512-2014 standard, the hot air aging performance test was carried out in a hot air aging chamber at a test temperature of 100℃ for 48 hours. The tensile strength of the sealing material before and after aging was tested (in accordance with GB / T 528-2009).

[0066] Compression set test: The compression set test was carried out in a hot air aging chamber in accordance with GB / T 7759.1-2015. The specimen was a cylinder with a diameter of (29±0.5mm) and a height of (12.5±0.5mm). The test temperature was 120℃ and the test time was 24h. The test environment was hot air.

[0067] Hardness testing: The Shore A hardness test was conducted in accordance with standard GB / T531.1-2008;

[0068] The test results are shown in Table 1:

[0069] Table 1: Performance Test Results

[0070]

[0071] As can be seen from Table 1, the aging-resistant sealing material prepared by this invention has excellent aging resistance and can be widely used in automobiles, electronics, industrial manufacturing and other fields.

[0072] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. An age resistant sealant material characterized by, The raw materials include the following components in parts by weight: butyronitrile rubber 50-70 parts, chlorobutyl rubber 15-25 parts, plasticizer 1-3 parts, zinc oxide 8-15 parts, silane coupling agent 2-4 parts, composite antioxidant 2-4 parts, sulfur 1.5-2.5 parts, vulcanization accelerator 0.3-1 part, lubricant 1-3 parts; The composite antioxidant is prepared by refluxing a methyl imidazole product and an imido diphenylamine product at 85℃ for 3-5 hours; the imido diphenylamine product is prepared by reacting maleic anhydride and an amino-terminated diphenylamine product at room temperature for 1.5-3.5 hours, then adding anhydrous sodium acetate, hydroquinone and acetic anhydride, and stirring at 50℃ for 2-3 hours; the amino-terminated diphenylamine product is prepared by refluxing 2-chloroethylamine hydrochloride and 4,4'-diaminodiphenylamine at 80℃ for 4-6 hours; The methyl imidazole product is prepared by esterification of 4-methyl-5-hydroxymethyl imidazole hydrochloride and 3-chloropropionic acid.

2. The weatherable encapsulant of claim 1, wherein, The composite antioxidant is prepared by the following steps: Step A1, under nitrogen protection, 2-chloroethylamine hydrochloride is mixed with ethanol, then anhydrous sodium carbonate is added and stirred for 30 minutes, heated to 80℃ and refluxed, then 4,4'-diaminodiphenylamine is added, the temperature is maintained and stirred for 4-6 hours, then cooled to room temperature, and distilled under reduced pressure to obtain the amino-terminated diphenylamine product; Step A2, maleic anhydride is dissolved in DMF, denoted as reaction liquid 1; the amino-terminated diphenylamine product is mixed in DMF, denoted as reaction liquid 2; reaction liquid 2 is slowly added to reaction liquid 1, and reacted at room temperature for 1.5-3.5 hours, then anhydrous sodium acetate and hydroquinone are added and stirred for 15-30 minutes, then acetic anhydride is added, and the temperature is raised to 50℃ and stirred for 2-3 hours, then cooled and poured into crushed ice, and left to stand for 5 minutes, then filtered, washed, dried, recrystallized to obtain the imido diphenylamine product; Step A3, under nitrogen protection, the imido diphenylamine product and DMF are mixed, then triethylamine is added and stirred until uniform, then the methyl imidazole product is added and stirred until uniform, and the temperature is raised to 85℃ and refluxed for 3-5 hours, then cooled to room temperature, rotary evaporated, purified by chromatographic column, twice rotary evaporated, and vacuum dried to obtain the composite antioxidant.

3. The weatherable encapsulant of claim 2, wherein, In step A1, the amount ratio of 2-chloroethylamine hydrochloride, ethanol, anhydrous sodium carbonate and 4,4'-diaminodiphenylamine is 0.01-0.03 mol: 100 mL: 0.016-0.048 mol: 0.005-0.015 mol.

4. The weatherable encapsulant of claim 2, wherein, In step A2, the molar ratio of maleic anhydride and the amino-terminated diphenylamine product is 2:

1.

5. The weatherable encapsulant of claim 2, wherein, In step A2, the molar ratio of anhydrous sodium acetate, hydroquinone, acetic anhydride and maleic anhydride is 0.23-0.25: 0.15-0.18: 1.5-1.7:

1.

6. The weatherable encapsulant of claim 2, wherein, In step A3, the amount ratio of the imido diphenylamine product, DMF, triethylamine and the methyl imidazole product is 0.01-0.03 mol: 50 mL: 0.012-0.035 mol: 0.01-0.03 mol.

7. The weatherable encapsulant of claim 2, wherein, The methyl imidazole product in step A3 is prepared by the following steps: The 4-methyl-5-hydroxymethyl imidazole hydrochloride, sodium hydroxide and DMF are mixed and stirred uniformly, the precipitate is filtered, the DMF is distilled off under reduced pressure, washed, the product is collected, 3-chloropropionic acid and toluene are added to the product, stirred under ice water bath, 98wt% concentrated sulfuric acid is added dropwise while stirring, the ice water bath is maintained for 2.5-3.5h, and then stirred at room temperature for 12-18h, distilled under reduced pressure, saturated sodium bicarbonate solution is added, and then filtered and dried under reduced pressure to obtain the methyl imidazole product.

8. The weatherable encapsulant of claim 7, wherein, The amount ratio of the 4-methyl-5-hydroxymethyl imidazole hydrochloride, sodium hydroxide, DMF, 3-chloropropionic acid, toluene, concentrated sulfuric acid and saturated sodium bicarbonate solution in the methyl imidazole product is 0.02-0.03mol:0.08-0.12g:100mL:0.01mol:50mL:3-4mL:200mL.

9. The weatherable encapsulant of claim 1, wherein, The plasticizer is one of dioctyl phthalate or epoxy soybean oil, the silane coupling agent is one of KH550, KH560 or KH570, the vulcanization accelerator is one of accelerator DM or accelerator TMTD, and the lubricant is one of zinc stearate or polyethylene wax.

10. A process for the preparation of the weatherable sealing material according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: In step S1, the raw materials are weighed, the initial temperature of the internal mixer is set to 50-60℃, the zinc oxide, silane coupling agent, composite antioxidant and lubricant are added into the internal mixer and stirred uniformly, then the butyl nitrile rubber, chlorobutyl rubber, plasticizer, sulfur and vulcanization accelerator are added in sequence and mixed at 80-90℃ for 5-10min, then the temperature is increased to 100-110℃ and stirred for 50-70min, and then the mixture is aged for 5h to obtain the mixed material. In step S2, the mixed material is put into a double screw extruder, melted, extruded, granulated, dried, and then extruded and molded to obtain the aging-resistant sealing material, the extrusion temperature of the double screw extruder is 175-195℃, and the rotating speed is 200rpm / min.

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