TPV sealing material and preparation method thereof

Abstract

The invention relates to the technical field of thermoplastic vulcanizates, and discloses a TPV sealing material and a preparation method thereof. The TPV sealing material is prepared from the following raw materials in parts by weight: 10 to 30 parts of PP resin, 40 to 60 parts of EPDM rubber, 10 to 20 parts of polylactic acid, 15 to 25 parts of filler, 0.5 to 1.5 parts of vulcanizing agent, 0.3 to 1.5 parts of vulcanization accelerator, 5 to 10 parts of compatilizer, 1 to 4 parts of modified heat stabilizer and 0.5 to 3 parts of modified anti-aging agent. Through preparation of the modified heat stabilizer, structural damage or sealing failure caused by thermal aging of a system can be reduced, and the service life of the sealing material is greatly prolonged; the preparation of the modified anti-aging agent can effectively resist the corrosion of environmental factors such as thermal oxidation and ozone to the system, and prevent the problems of cracking, hardening, elasticity attenuation, sealing failure and the like of the sealing material after long-term use.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic vulcanized rubber technology, specifically to a TPV sealing material and its preparation method. Background Technology

[0002] Sealing materials, as core materials ensuring the airtightness, watertightness, and oiltightness of equipment systems, are widely used in key fields such as transportation, industrial manufacturing, home appliances and electronics, new energy, and aerospace. Their performance and reliability directly determine the operating efficiency, service life, and safety stability of end products. Thermoplastic vulcanizate (TPV), a novel blended elastomer prepared through dynamic full vulcanization technology, perfectly meets the needs of these industries. Its core structure consists of micron-sized cross-linked rubber particles (mostly EPDM) uniformly dispersed in a continuous phase matrix of thermoplastic plastics (such as PP), achieving an organic integration of the excellent elasticity of rubber and the thermoplastic processing properties of plastics. TPV sealing materials have significant advantages. In terms of processing, they can be formed through efficient processes such as injection molding and extrusion without the need for solvent assistance, and the materials are recyclable, meeting environmental protection and sustainable development requirements. However, there are still technical bottlenecks that need to be overcome in high-end applications, especially in terms of heat resistance and anti-aging systems. In terms of heat resistance, conventional TPV is prone to degradation of the rubber phase cross-linking structure, decrease in elastic modulus, and surface cracking under ultra-high temperature conditions such as automotive engine compartments and industrial high-temperature equipment, leading to seal failure. Regarding aging resistance, TPV is susceptible to synergistic corrosion from oxygen, ozone, ultraviolet radiation, and chemical media during long-term outdoor exposure or in complex media environments, resulting in material hardening and deterioration of sealing performance. Therefore, improving the upper limit of high temperature resistance and optimizing the synergistic effect and long-term effectiveness of the anti-aging agent system have become key technological directions for expanding the high-end application scenarios of TPV sealing materials.

[0003] Patent application number 202211073124.3 discloses a talc-based high-temperature resistant sealing material and its preparation method. It uses talc as the base material, which has a high melting point and its layered structure gives it special lubricity. Glass fiber is used as a reinforcing material, giving the sealing material both high-temperature resistance and mechanical properties. However, long-term exposure to ultraviolet light or humid environments may lead to performance degradation of talc, and it is not suitable for sealing applications requiring high transparency or long-term outdoor use. Patent application number 201710037765.6 discloses a sealing material and its preparation method, using a mixture of various commercially available antioxidants to improve the material's aging resistance. However, the dispersion of multiple antioxidants obtained through physical blending is random in actual production, and their synergistic efficiency is lower than that of combined antioxidants with multifunctional groups. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a TPV sealing material and its preparation method.

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

[0006] A TPV sealing material comprises the following raw materials in parts by weight: 10-30 parts PP resin, 40-60 parts EPDM rubber, 10-20 parts polylactic acid, 15-25 parts filler, 0.5-1.5 parts vulcanizing agent, 0.3-1.5 parts vulcanization accelerator, 5-10 parts compatibilizer, 1-4 parts modified heat stabilizer, and 0.5-3 parts modified antioxidant;

[0007] The filler is one of mica, light calcium carbonate, and barium sulfate;

[0008] The vulcanizing agent is a di-25 vulcanizing agent;

[0009] The vulcanization accelerator is one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and triallyl cyanurate.

[0010] The compatibilizer is maleic anhydride-grafted polyethylene.

[0011] The modified heat stabilizer is prepared by the following steps:

[0012] Step A1: Mix paraformaldehyde and toluene, stir, then add furfural at 60°C dropwise. After the addition is complete, add p-nitrophenol solution, heat to 80°C, reflux for 5 hours. After the reaction is complete, pour the reaction solution into 6wt% sodium hydroxide aqueous solution, stir for 10 minutes, wash with water until neutral, rotary evaporate, and vacuum dry to obtain benzoxazine derivative.

[0013] Furthermore, the ratio of paraformaldehyde, toluene, furfuralamine, p-nitrophenol solution, and sodium hydroxide aqueous solution is 1-1.5 mol: 60-80 mL: 0.5-0.75 mol: 40-60 mL: 70-100 mL;

[0014] Furthermore, the p-nitrophenol solution is prepared by mixing p-nitrophenol and toluene in a volume ratio of 0.5-0.75 mol: 40-60 mL;

[0015] In step A1, paraformaldehyde, p-nitrophenol, and furfurylamine undergo the Mannich reaction. The introduced nitro group provides the reaction conditions for the subsequent nucleophilic substitution reaction. The resulting benzoxazine structure has excellent heat resistance. Introducing the furan ring into the benzoxazine structure increases the char residue of the system and further improves its thermal stability.

[0016] Step A2: Under nitrogen protection, 1-amino-5-naphthol, anhydrous potassium carbonate and N,N-dimethylformamide (DMF) were mixed, heated to 80°C, stirred for 30 min, and then reacted for 1 h. The benzoxazine derivative was added, and the reaction continued for 7 h. The mixture was cooled to room temperature, and 4 wt% sodium hydroxide aqueous solution was added. The mixture was allowed to stand to precipitate and filtered. After washing and vacuum drying, the naphthylbenzoxazine derivative was obtained.

[0017] Furthermore, the ratio of 1-amino-5-naphthol, anhydrous potassium carbonate, DMF, benzoxazine derivative and sodium hydroxide aqueous solution is 0.5-1 mol: 0.5-1 mol: 400-600 mL: 0.5-1 mol: 200-250 mL;

[0018] In step A2, the benzoxazine derivative and 1-amino-5-naphthol undergo a nucleophilic substitution reaction. The introduced amino group provides the reaction conditions for the subsequent amidation reaction. The introduced naphthalene ring structure has a stable conjugated structure, which effectively enhances the thermal decomposition ability of the system and can improve the heat resistance of the system.

[0019] Step A3: Under nitrogen protection, 1,4,5,8-naphthalenetetracarboxylic anhydride and DMF are mixed and stirred at room temperature for 30 min. Naphthylbenzoxazine derivative is added and reacted at room temperature for 12 h. Then triethylamine and acetic anhydride are added and reacted at room temperature for 12 h. After washing and drying, the modified heat stabilizer is obtained.

[0020] Furthermore, the molar ratio of 1,4,5,8-naphthyltetracarboxylic anhydride, DMF, naphthylbenzoxazine derivative, triethylamine, and acetic anhydride is 0.41-0.61 mol: 200-300 mL: 0.4-0.6 mol: 1.2-1.8 mol: 1.2-1.8 mol;

[0021] In step A3, 1,4,5,8-naphthalenetetracarboxylic anhydride and naphthylbenzoxazine derivative undergo an amidation reaction. The introduced imide structure can improve the heat resistance of the system, enabling it to exhibit excellent mechanical properties and thermal stability at high temperatures. At the same time, it works synergistically with the naphthalene ring and benzoxazine structure to further improve the thermal stability of the system.

[0022] The modified antioxidant is prepared by the following steps:

[0023] Step B1: Mix epichlorohydrin and 2-mercaptobenzimidazole, add triethylamine and methanol, react at 45°C for 3.5 h, then rotary evaporate and vacuum dry, then mix with 5 wt% sodium hydroxide aqueous solution, react at 85°C for 4 h, separate the liquid, rotary evaporate and vacuum dry to obtain intermediate product 1;

[0024] Furthermore, the ratio of epichlorohydrin, 2-mercaptobenzimidazole, triethylamine, methanol, and sodium hydroxide aqueous solution is 0.8-1.2 mol: 0.67-1 mol: 0.02-0.03 mol: 300-400 mL: 450-680 mL;

[0025] In step B1, epichlorohydrin and 2-mercaptobenzimidazole first undergo a nucleophilic ring-opening reaction. The generated hydroxyl and chlorine atoms undergo an epoxy cyclization reaction under the action of sodium hydroxide to generate an epoxy group. The introduced benzimidazole can capture free radicals to form a stable compound, prevent the diffusion of the oxidation chain reaction, thereby inhibiting the aging process of the system and extending its service life.

[0026] Step B2: Mix intermediate product 1, N-phenyl-p-phenylenediamine and xylene, add salicylic acid, reflux at 150°C for 8 hours, then wash three times with 3wt% sodium bicarbonate aqueous solution, then wash three times with water, rotary evaporate and vacuum dry to obtain intermediate product 2.

[0027] Furthermore, the ratio of intermediate 1, N-phenyl-p-phenylenediamine, xylene, salicylic acid, sodium bicarbonate aqueous solution, and water is 0.4-0.6 mol: 0.44-0.66 mol: 100-200 mL: 0.01-0.02 mol: 300-400 mL: 400-600 mL;

[0028] In step B2, intermediate 1 and N-phenyl-p-phenylenediamine undergo a nucleophilic ring-opening reaction. The introduced hydroxyl group provides the reaction conditions for the subsequent esterification reaction. The diphenylamine structure can block the oxidation chain reaction and absorb ozone, converting it into a harmless substance. It has excellent resistance to thermo-oxidation and ozone.

[0029] Step B3: Mix intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid and toluene, stir, heat to 140℃, reflux for 5h, add ethyl acetate, wash with 10wt% sodium bicarbonate aqueous solution, then wash with water and saturated sodium chloride solution in sequence, separate the liquid, dry the liquid phase, filter, distill under reduced pressure and dry the solid phase to obtain intermediate product 3.

[0030] Furthermore, the ratio of intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, toluene, ethyl acetate, sodium bicarbonate aqueous solution, water, and saturated sodium chloride solution is 0.2-0.4 mol: 0.21-0.41 mol: 0.02-0.04 mol: 200-300 mL: 200-250 mL: 200-300 mL: 300 mL: 300 mL;

[0031] In step B3, intermediate 2 and p-aminobenzoic acid undergo esterification, introducing an amino group into the system and providing reaction conditions for the subsequent condensation reaction.

[0032] Step B4: Mix thiourea and distilled water, stir at 500 r / min, heat to 100℃, add intermediate product 3 solution dropwise over 1 hour, react for 5 hours after the addition is complete, then cool to room temperature, filter, wash and dry to obtain modified antioxidant.

[0033] Furthermore, the ratio of thiourea, distilled water, and intermediate product 3 solution is 0.1-0.2 mol: 350-700 mL: 350-700 mL;

[0034] Furthermore, the intermediate product 3 solution is prepared by mixing intermediate product 3 and distilled water at a volume ratio of 0.21-0.42 mol: 350-700 mL;

[0035] In step B4, intermediate product 3 undergoes a condensation reaction with thiourea. The introduced thiourea structure can react with ozone to consume ozone molecules and delay the aging of the system. At the same time, the carbon-sulfur bond can improve the toughness of the system. In synergy with diphenylamine and benzimidazole, it can further improve the mechanical properties and aging resistance of the system.

[0036] A method for preparing a TPV sealing material includes the following steps:

[0037] Step S1: Weigh the raw materials according to the weight proportions, and perform the first plasticizing of PP resin, EPDM rubber, vulcanizing agent, vulcanization accelerator, modified heat stabilizer and modified antioxidant in a twin-screw extruder to obtain a semi-finished product. The screw speed is 500-650 r / min and the plasticizing temperature is 160-200℃.

[0038] Step S2: The semi-finished product, polylactic acid, filler and compatibilizer are subjected to a second plasticizing process in a twin-screw extruder to obtain TPV sealing material. The screw speed is 400-500 r / min and the plasticizing temperature is 160-200℃.

[0039] The beneficial effects of this invention are:

[0040] The TPV sealing material of this invention can be widely used in the production of automotive, construction, electronics, and industrial sealing products. When used in the manufacture of seals, the TPV sealing material of this invention, relying on the highly efficient protective properties of the modified heat stabilizer, possesses excellent thermal stability. Even during high-temperature processing or prolonged exposure to high-temperature conditions, it can stably maintain its appearance integrity and core sealing performance, reducing structural damage or seal failure caused by thermal aging and significantly extending the service life of the seals. Simultaneously, through the synergistic effect of the modified antioxidant, the material's resistance to comprehensive aging is significantly improved, effectively resisting the erosion of the material by environmental factors such as heat, oxygen, and ozone, preventing problems such as cracking, hardening, elasticity loss, and seal failure after long-term use. Compared with existing technologies, the TPV sealing material of this invention not only has more balanced core performance but also good processing fluidity, excellent compatibility with various substrates, and easy control of the production process, thus possessing broad market application prospects.

[0041] The modified heat stabilizer of this invention first undergoes a Mannich reaction with paraformaldehyde, p-nitrophenol, and furfurylamine. The introduced nitro group provides the reaction conditions for subsequent nucleophilic substitution reactions, resulting in a benzoxazine structure with excellent heat resistance. Introducing a furan ring into the benzoxazine structure increases the char residue of the system, further improving its thermal stability. Subsequently, a nucleophilic substitution reaction occurs with 1-amino-5-naphthol. The introduced naphthalene ring structure has a stable conjugated structure, effectively enhancing the system's thermal decomposition ability and improving its heat resistance. Finally, an amidation reaction occurs with 1,4,5,8-naphthalenetetracarboxylic anhydride. The introduced imide structure improves the system's heat resistance, enabling it to exhibit excellent mechanical properties and thermal stability at high temperatures. Simultaneously, the imide structure synergistically enhances the system's thermal stability with the naphthalene ring and benzoxazine structure.

[0042] The modified antioxidant of this invention first undergoes a nucleophilic ring-opening reaction between epichlorohydrin and 2-mercaptobenzimidazole. The resulting hydroxyl and chlorine atoms undergo an epoxy cyclization reaction under the action of sodium hydroxide, generating an epoxy group. The introduced benzimidazole can capture free radicals to form a stable compound, preventing the diffusion of the oxidation chain reaction, thereby inhibiting the aging process of the system and extending its service life. Next, a nucleophilic ring-opening reaction occurs with N-phenyl-p-phenylenediamine. The diphenylamine structure can block the oxidation chain reaction and absorb ozone, converting it into a harmless substance, exhibiting excellent resistance to thermo-oxidation and ozone. Subsequently, an esterification reaction occurs with p-aminobenzoic acid, introducing an amino group into the system and providing reaction conditions for subsequent condensation reactions. Finally, a condensation reaction occurs with thiourea. The introduced thiourea structure can react with ozone, consuming ozone molecules and delaying system aging. Simultaneously, the carbon-sulfur bond can improve the system's toughness, synergistically enhancing the mechanical properties and aging resistance of the system in conjunction with diphenylamine and benzimidazole. Detailed Implementation

[0043] 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.

[0044] Example 1: The modified heat stabilizer was prepared by the following steps:

[0045] Step A1: Mix paraformaldehyde and toluene, stir, then add furfurylamine dropwise at 60°C. After the addition is complete, add p-nitrophenol solution, heat to 80°C, and reflux for 5 hours. After the reaction is complete, pour the reaction solution into a 6wt% sodium hydroxide aqueous solution, stir for 10 minutes, wash with water until neutral, rotary evaporate, and vacuum dry to obtain benzoxazine derivative. The ratio of paraformaldehyde, toluene, furfurylamine, p-nitrophenol solution, and sodium hydroxide aqueous solution is 1 mol: 60 mL: 0.5 mol: 40 mL: 70 mL. The p-nitrophenol solution is prepared by mixing p-nitrophenol and toluene in a ratio of 0.5 mol: 40 mL.

[0046] Step A2: Under nitrogen protection, 1-amino-5-naphthol, anhydrous potassium carbonate, and DMF were mixed, heated to 80°C, stirred for 30 min, and then reacted for 1 h. The benzoxazine derivative was added, and the reaction continued for 7 h. After cooling to room temperature, 4 wt% sodium hydroxide aqueous solution was added, the mixture was allowed to stand to precipitate, filtered, washed, and vacuum dried to obtain naphthylbenzoxazine derivative. The ratio of 1-amino-5-naphthol, anhydrous potassium carbonate, DMF, benzoxazine derivative, and sodium hydroxide aqueous solution was 0.5 mol: 0.5 mol: 400 mL: 0.5 mol: 200 mL.

[0047] Step A3: Under nitrogen protection, 1,4,5,8-naphthyltetracarboxylic anhydride and DMF were mixed and stirred at room temperature for 30 min. Naphthylbenzoxazine derivative was added and reacted at room temperature for 12 h. Then triethylamine and acetic anhydride were added and reacted at room temperature for 12 h. The mixture was washed and dried to obtain the modified heat stabilizer. The ratio of 1,4,5,8-naphthyltetracarboxylic anhydride, DMF, naphthylbenzoxazine derivative, triethylamine and acetic anhydride was 0.41 mol: 200 mL: 0.4 mol: 1.2 mol: 1.2 mol.

[0048] The modified antioxidant is prepared by the following steps:

[0049] Step B1: Epichlorohydrin and 2-mercaptobenzimidazole were mixed, and triethylamine and methanol were added. The mixture was reacted at 45°C for 3.5 h, then rotary evaporated and vacuum dried. The mixture was then mixed with a 5 wt% sodium hydroxide aqueous solution and reacted at 85°C for 4 h. The mixture was separated, rotary evaporated, and vacuum dried to obtain intermediate product 1. The ratio of epichlorohydrin, 2-mercaptobenzimidazole, triethylamine, methanol, and sodium hydroxide aqueous solution was 0.8 mol: 0.67 mol: 0.02 mol: 300 mL: 450 mL.

[0050] Step B2: Mix intermediate product 1, N-phenyl-p-phenylenediamine and xylene, add salicylic acid, reflux at 150℃ for 8 hours, then wash three times with 3wt% sodium bicarbonate aqueous solution, then wash three times with water, rotary evaporate and vacuum dry to obtain intermediate product 2. The ratio of intermediate product 1, N-phenyl-p-phenylenediamine, xylene, salicylic acid, sodium bicarbonate aqueous solution and water is 0.4mol:0.44mol:100mL:0.01mol:300mL:400mL;

[0051] Step B3: Mix intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, and toluene, stir, heat to 140℃, reflux for 5 hours, add ethyl acetate, wash with 10wt% sodium bicarbonate aqueous solution, then wash successively with water and saturated sodium chloride solution, separate the liquid phase, dry the liquid phase, filter, distill under reduced pressure, and dry the solid phase to obtain intermediate product 3. The ratio of intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, toluene, ethyl acetate, sodium bicarbonate aqueous solution, water, and saturated sodium chloride solution is 0.2mol:0.21mol:0.02mol:200mL:200mL:300mL:300mL;

[0052] Step B4: Mix thiourea and distilled water, stir at 500 r / min, heat to 100℃, add intermediate product 3 solution dropwise over 1 hour, react for 5 hours after the addition is complete, then cool to room temperature, filter, wash, and dry to obtain the modified antioxidant. The ratio of thiourea, distilled water, and intermediate product 3 solution is 0.1 mol: 350 mL: 350 mL. Intermediate product 3 solution is prepared by mixing intermediate product 3 and distilled water at a ratio of 0.21 mol: 350 mL.

[0053] Example 2: The modified heat stabilizer was prepared by the following steps:

[0054] Step A1: Mix paraformaldehyde and toluene, stir, then add furfurylamine dropwise at 60°C. After the addition is complete, add p-nitrophenol solution, heat to 80°C, and reflux for 5 hours. After the reaction is complete, pour the reaction solution into a 6wt% sodium hydroxide aqueous solution, stir for 10 minutes, wash with water until neutral, rotary evaporate, and vacuum dry to obtain benzoxazine derivative. The ratio of paraformaldehyde, toluene, furfurylamine, p-nitrophenol solution, and sodium hydroxide aqueous solution is 1.25mol:70mL:0.62mol:50mL:85mL. The p-nitrophenol solution is prepared by mixing p-nitrophenol and toluene in a ratio of 0.62mol:50mL.

[0055] Step A2: Under nitrogen protection, 1-amino-5-naphthol, anhydrous potassium carbonate, and DMF were mixed, heated to 80°C, stirred for 30 min, and then reacted for 1 h. The benzoxazine derivative was added, and the reaction continued for 7 h. After cooling to room temperature, 4 wt% sodium hydroxide aqueous solution was added, the mixture was allowed to stand to precipitate, filtered, washed, and vacuum dried to obtain naphthylbenzoxazine derivative. The ratio of 1-amino-5-naphthol, anhydrous potassium carbonate, DMF, benzoxazine derivative, and sodium hydroxide aqueous solution was 0.75 mol: 0.75 mol: 500 mL: 0.75 mol: 225 mL.

[0056] Step A3: Under nitrogen protection, 1,4,5,8-naphthyltetracarboxylic anhydride and DMF were mixed and stirred at room temperature for 30 min. Naphthylbenzoxazine derivative was added and reacted at room temperature for 12 h. Then triethylamine and acetic anhydride were added and reacted at room temperature for 12 h. The mixture was washed and dried to obtain the modified heat stabilizer. The ratio of 1,4,5,8-naphthyltetracarboxylic anhydride, DMF, naphthylbenzoxazine derivative, triethylamine and acetic anhydride was 0.51 mol: 250 mL: 0.5 mol: 1.5 mol: 1.5 mol.

[0057] The modified antioxidant is prepared by the following steps:

[0058] Step B1: Epichlorohydrin and 2-mercaptobenzimidazole were mixed, and triethylamine and methanol were added. The mixture was reacted at 45°C for 3.5 h, then rotary evaporated and vacuum dried. The mixture was then mixed with a 5 wt% sodium hydroxide aqueous solution and reacted at 85°C for 4 h. The mixture was separated, rotary evaporated, and vacuum dried to obtain intermediate product 1. The ratio of epichlorohydrin, 2-mercaptobenzimidazole, triethylamine, methanol, and sodium hydroxide aqueous solution was 1.0 mol: 0.84 mol: 0.025 mol: 350 mL: 565 mL.

[0059] Step B2: Mix intermediate product 1, N-phenyl-p-phenylenediamine and xylene, add salicylic acid, reflux at 150℃ for 8 hours, then wash three times with 3wt% sodium bicarbonate aqueous solution, then wash three times with water, rotary evaporate and vacuum dry to obtain intermediate product 2. The ratio of intermediate product 1, N-phenyl-p-phenylenediamine, xylene, salicylic acid, sodium bicarbonate aqueous solution and water is 0.5mol:0.55mol:150mL:0.015mol:350mL:500mL;

[0060] Step B3: Mix intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, and toluene, stir, heat to 140℃, reflux for 5 hours, add ethyl acetate, wash with 10wt% sodium bicarbonate aqueous solution, then wash successively with water and saturated sodium chloride solution, separate the liquid, dry the liquid phase, filter, distill under reduced pressure, and dry the solid phase to obtain intermediate product 3. The ratio of intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, toluene, ethyl acetate, sodium bicarbonate aqueous solution, water, and saturated sodium chloride solution is 0.3mol:0.31mol:0.03mol:250mL:225mL:250mL:300mL:300mL;

[0061] Step B4: Mix thiourea and distilled water, stir at 500 r / min, heat to 100℃, add intermediate product 3 solution dropwise over 1 hour, react for 5 hours after the addition is complete, then cool to room temperature, filter, wash, and dry to obtain the modified antioxidant. The ratio of thiourea, distilled water, and intermediate product 3 solution is 0.15 mol: 525 mL: 525 mL. Intermediate product 3 solution is prepared by mixing intermediate product 3 and distilled water at a ratio of 0.315 mol: 525 mL.

[0062] Example 3: The modified heat stabilizer was prepared by the following steps:

[0063] Step A1: Mix paraformaldehyde and toluene, stir, then add furfurylamine dropwise at 60°C. After the addition is complete, add p-nitrophenol solution, heat to 80°C, and reflux for 5 hours. After the reaction is complete, pour the reaction solution into a 6wt% sodium hydroxide aqueous solution, stir for 10 minutes, wash with water until neutral, rotary evaporate, and vacuum dry to obtain benzoxazine derivative. The ratio of paraformaldehyde, toluene, furfurylamine, p-nitrophenol solution, and sodium hydroxide aqueous solution is 1.5mol:80mL:0.75mol:60mL:100mL. The p-nitrophenol solution is prepared by mixing p-nitrophenol and toluene in a ratio of 0.75mol:60mL.

[0064] Step A2: Under nitrogen protection, 1-amino-5-naphthol, anhydrous potassium carbonate, and DMF were mixed, heated to 80°C, stirred for 30 min, and then reacted for 1 h. The benzoxazine derivative was added, and the reaction continued for 7 h. After cooling to room temperature, 4 wt% sodium hydroxide aqueous solution was added, the mixture was allowed to stand to precipitate, filtered, washed, and vacuum dried to obtain naphthylbenzoxazine derivative. The ratio of 1-amino-5-naphthol, anhydrous potassium carbonate, DMF, benzoxazine derivative, and sodium hydroxide aqueous solution was 1 mol: 1 mol: 600 mL: 1 mol: 250 mL.

[0065] Step A3: Under nitrogen protection, 1,4,5,8-naphthyltetracarboxylic anhydride and DMF were mixed and stirred at room temperature for 30 min. Naphthylbenzoxazine derivative was added and reacted at room temperature for 12 h. Then triethylamine and acetic anhydride were added and reacted at room temperature for 12 h. The mixture was washed and dried to obtain the modified heat stabilizer. The ratio of 1,4,5,8-naphthyltetracarboxylic anhydride, DMF, naphthylbenzoxazine derivative, triethylamine and acetic anhydride was 0.61 mol: 300 mL: 0.6 mol: 1.8 mol: 1.8 mol.

[0066] The modified antioxidant is prepared by the following steps:

[0067] Step B1: Epichlorohydrin and 2-mercaptobenzimidazole were mixed, and triethylamine and methanol were added. The mixture was reacted at 45°C for 3.5 h, then rotary evaporated and vacuum dried. The mixture was then mixed with a 5 wt% sodium hydroxide aqueous solution and reacted at 85°C for 4 h. The mixture was separated, rotary evaporated, and vacuum dried to obtain intermediate product 1. The ratio of epichlorohydrin, 2-mercaptobenzimidazole, triethylamine, methanol, and sodium hydroxide aqueous solution was 1.2 mol: 1 mol: 0.03 mol: 400 mL: 680 mL.

[0068] Step B2: Mix intermediate product 1, N-phenyl-p-phenylenediamine and xylene, add salicylic acid, reflux at 150℃ for 8 hours, then wash three times with 3wt% sodium bicarbonate aqueous solution, then wash three times with water, rotary evaporate and vacuum dry to obtain intermediate product 2. The ratio of intermediate product 1, N-phenyl-p-phenylenediamine, xylene, salicylic acid, sodium bicarbonate aqueous solution and water is 0.6mol:0.66mol:200mL:0.02mol:400mL:600mL;

[0069] Step B3: Mix intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, and toluene, stir, heat to 140℃, reflux for 5 hours, add ethyl acetate, wash with 10wt% sodium bicarbonate aqueous solution, then wash successively with water and saturated sodium chloride solution, separate the liquid phase, dry the liquid phase, filter, distill under reduced pressure, and dry the solid phase to obtain intermediate product 3. The ratio of intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, toluene, ethyl acetate, sodium bicarbonate aqueous solution, water, and saturated sodium chloride solution is 0.4mol:0.41mol:0.04mol:300mL:250mL:300mL:300mL:300mL;

[0070] Step B4: Mix thiourea and distilled water, stir at 500 r / min, heat to 100℃, add intermediate product 3 solution dropwise over 1 hour, react for 5 hours after the addition is complete, then cool to room temperature, filter, wash, and dry to obtain the modified antioxidant. The ratio of thiourea, distilled water, and intermediate product 3 solution is 0.2 mol: 700 mL: 700 mL. Intermediate product 3 solution is prepared by mixing intermediate product 3 and distilled water at a ratio of 0.42 mol: 700 mL.

[0071] Example 4: A method for preparing a TPV sealing material, comprising the following steps:

[0072] 10 parts PP resin, 40 parts EPDM rubber, 10 parts polylactic acid, 15 parts mica, 0.5 parts bis(2,5)-5-sulfurizing agent, 0.3 parts trimethylolpropane triacrylate, 5 parts maleic anhydride-grafted polyethylene, 1 part modified heat stabilizer prepared in Example 1, and 0.5 parts modified antioxidant prepared in Example 1.

[0073] Step S1: Weigh the raw materials according to the weight proportions, and perform the first plasticizing of PP resin, EPDM rubber, bis(2,5-dimethylolpropane) vulcanizing agent, trimethylolpropane triacrylate, modified heat stabilizer prepared in Example 1 and modified antioxidant prepared in Example 1 in a twin-screw extruder to obtain a semi-finished product. The screw speed is 500 r / min and the plasticizing temperature is 160℃.

[0074] Step S2: The semi-finished product, polylactic acid, mica, and maleic anhydride-grafted polyethylene are subjected to a second plasticizing process in a twin-screw extruder to obtain TPV sealing material. The screw speed is 400 r / min and the plasticizing temperature is 160℃.

[0075] Example 5: A method for preparing a TPV sealing material, comprising the following steps:

[0076] 20 parts PP resin, 50 parts EPDM rubber, 15 parts polylactic acid, 20 parts light calcium carbonate, 1 part bis(2,5) sulfide, 1 part trimethylolpropane trimethacrylate, 7 parts maleic anhydride grafted polyethylene, 2 parts modified heat stabilizer prepared in Example 2, and 1 part modified antioxidant prepared in Example 2.

[0077] Step S1: Weigh the raw materials according to the weight proportions, and perform the first plasticizing of PP resin, EPDM rubber, bis(2,5)-pentasulfurizing agent, trimethylolpropane trimethacrylate, modified heat stabilizer prepared in Example 2 and modified antioxidant prepared in Example 2 in a twin-screw extruder to obtain a semi-finished product. The screw speed is 600 r / min and the plasticizing temperature is 180℃.

[0078] Step S2: The semi-finished product, polylactic acid, light calcium carbonate, and maleic anhydride-grafted polyethylene are subjected to a second plasticizing process in a twin-screw extruder to obtain TPV sealing material. The screw speed is 450 r / min and the plasticizing temperature is 180℃.

[0079] Example 6: A method for preparing a TPV sealing material, comprising the following steps:

[0080] 30 parts PP resin, 60 parts EPDM rubber, 20 parts polylactic acid, 25 parts barium sulfate, 1.5 parts di(2,5) sulfide, 1.5 parts triallyl cyanurate, 10 parts maleic anhydride-grafted polyethylene, 4 parts modified heat stabilizer prepared in Example 3, and 3 parts modified antioxidant prepared in Example 3.

[0081] Step S1: Weigh the raw materials according to the weight proportions, and perform the first plasticizing of PP resin, EPDM rubber, bis(2,5)-pentasulfurizing agent, triallyl cyanurate, modified heat stabilizer prepared in Example 3 and modified antioxidant prepared in Example 3 in a twin-screw extruder to obtain a semi-finished product. The screw speed is 650 r / min and the plasticizing temperature is 200℃.

[0082] Step S2: The semi-finished product, polylactic acid, barium sulfate, and maleic anhydride-grafted polyethylene are subjected to a second plasticizing process in a twin-screw extruder to obtain TPV sealing material. The screw speed is 500 r / min and the plasticizing temperature is 200℃.

[0083] Comparative Example 1: This comparative example is a sealing material, which differs from Example 6 in that calcium stearate is used instead of the modified heat stabilizer prepared in Example 3.

[0084] Comparative Example 2: This comparative example is a sealing material, which differs from Example 6 in that antioxidant 1010 is used instead of the modified antioxidant prepared in Example 3.

[0085] Comparative Example 3: This comparative example is a sealing material. The difference between this example and Example 6 is that calcium stearate is used instead of the modified heat stabilizer prepared in Example 3, and antioxidant 1010 is used instead of the modified antioxidant prepared in Example 3.

[0086] The sealing materials prepared in Examples 4-6 and Comparative Examples 1-3 were subjected to performance tests:

[0087] Hardness test: Tested according to GB / T 531.1-2008;

[0088] Tensile strength and elongation at break tests: conducted in accordance with GB / T 528-2009;

[0089] Ozone resistance test: After treating the material with an ozone concentration of 0.025% at 26℃ for 50 hours, observe the changes on the material surface;

[0090] Hot air aging: According to GB / T 3512-2014, the material is aged in an aging chamber at 175℃ for 72 hours to test its heat resistance, which is expressed by changes in tensile strength and elongation at break.

[0091] The test results are shown in Table 1:

[0092] Table 1: Performance Test Results

[0093]

[0094] As shown in Table 1, the TPV sealing material prepared by this invention has good mechanical properties, with a hardness of over 67D, a tensile strength of over 15.9 MPa, and an elongation at break of over 308%. Comparing the data of Example 6, Comparative Example 1, and Comparative Example 2, it can be seen that after hot air aging treatment, the sealing material of Example 6 has the lowest rate of change in mechanical properties, indicating that the modified heat stabilizer and modified antioxidant prepared by this invention can improve the heat resistance and aging resistance of the system. After ozone resistance testing, the material of Example 6 is better than that of Comparative Example 2, indicating that the modified antioxidant prepared by this invention can effectively absorb ozone and has excellent ozone resistance. This proves that the sealing material prepared by this invention has excellent mechanical properties, heat resistance, and aging resistance.

[0095] 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. A TPV encapsulant material characterized in that, The raw materials include the following components in parts by weight: 10-30 parts of PP resin, 40-60 parts of EPDM rubber, 10-20 parts of polylactic acid, 15-25 parts of filler, 0.5-1.5 parts of vulcanizing agent, 0.3-1.5 parts of vulcanization accelerator, 5-10 parts of compatibilizer, 1-4 parts of modified heat stabilizer, and 0.5-3 parts of modified antioxidant. The modified heat stabilizer is prepared by the following steps: Step A1, polyformaldehyde and toluene are mixed and stirred, then furfurylamine is added dropwise at 60℃, after the dropwise addition is completed, p-nitrophenol solution is added, the temperature is raised to 80℃, and reflux reaction is carried out for 5h, after the reaction is completed, the reaction liquid is poured into 6wt% sodium hydroxide aqueous solution, stirred for 10min, then washed with water until neutral, rotary evaporation, vacuum drying, to obtain a benzoxazine derivative; Step A2, 1-amino-5-naphthol, anhydrous potassium carbonate and DMF are mixed under nitrogen protection, the temperature is raised to 80℃, and stirred for 30min, then reacted for 1h, then the benzoxazine derivative is added, and the reaction is continued for 7h, then the temperature is cooled to room temperature, 4wt% sodium hydroxide aqueous solution is added, the precipitate is allowed to settle and suction filtered, washed, and vacuum dried to obtain a naphthyl benzoxazine derivative; Step A3, 1,4,5,8-naphthalene tetracarboxylic anhydride and DMF are mixed under nitrogen protection, stirred at room temperature for 30min, then the naphthyl benzoxazine derivative is added, and the reaction is carried out at room temperature for 12h, then triethylamine and acetic anhydride are added, and the reaction is carried out at room temperature for 12h, then washed and dried to obtain the modified heat stabilizer.

2. The TPV sealing material of claim 1, wherein, In step A1, the amount ratio of polyformaldehyde, toluene, furfurylamine, p-nitrophenol solution and sodium hydroxide aqueous solution is 1-1.5mol:60-80mL:0.5-0.75mol:40-60mL:70-100mL, and the p-nitrophenol solution is prepared by mixing p-nitrophenol and toluene in an amount ratio of 0.5-0.75mol:40-60mL.

3. The TPV sealing material of claim 1, wherein, In step A2, the amount ratio of 1-amino-5-naphthol, anhydrous potassium carbonate, DMF, benzoxazine derivative and sodium hydroxide aqueous solution is 0.5-1mol:0.5-1mol:400-600mL:0.5-1mol:200-250mL.

4. The TPV sealing material of claim 1, wherein, In step A3, the amount ratio of 1,4,5,8-naphthalene tetracarboxylic anhydride, DMF, naphthyl benzoxazine derivative, triethylamine and acetic anhydride is 0.41-0.61mol:200-300mL:0.4-0.6mol:1.2-1.8mol:1.2-1.8mol.

5. The TPV sealing material of claim 1, wherein, The modified antioxidant is prepared by the following steps: Step B1, epoxy chloropropane and 2-mercaptobenzimidazole are mixed, then triethylamine and methanol are added, and the reaction is carried out at 45℃ for 3.5h, then rotary evaporation, vacuum drying, then mixed with 5wt% sodium hydroxide aqueous solution, and the reaction is carried out at 85℃ for 4h, then liquid separation, rotary evaporation, vacuum drying to obtain intermediate product 1, and the amount ratio of epoxy chloropropane, 2-mercaptobenzimidazole, triethylamine, methanol and sodium hydroxide aqueous solution is 0.8-1.2mol:0.67-1mol:0.02-0.03mol:300-400mL:450-680mL; Step B2, mixing intermediate product 1, N-phenyl-p-phenylenediamine and xylene, adding salicylic acid, refluxing at 150℃ for 8h, then washing with 3wt% sodium bicarbonate solution for three times, then washing with water for three times, rotary evaporation, vacuum drying, to obtain intermediate product 2; Step B3, mixing intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid and toluene, stirring, heating to 140℃, refluxing for 5h, adding ethyl acetate, washing with 10wt% sodium bicarbonate solution, then washing with water and saturated sodium chloride solution in turn, separating, liquid phase drying, filtering, reduced pressure distillation, solid phase drying, to obtain intermediate product 3; Step B4, mixing thiourea and distilled water, stirring at 500r / min, heating to 100℃, adding intermediate product 3 solution dropwise within 1h, after dropwise addition, reacting for 5h, then cooling to room temperature, filtering, washing, drying, to obtain modified antioxidant.

6. The TPV sealing material of claim 5, wherein, The intermediate product 1, N-phenyl-p-phenylenediamine, xylene, salicylic acid, sodium bicarbonate solution and water in step B2 are used in a ratio of 0.4-0.6mol:0.44-0.66mol:100-200mL:0.01-0.02mol:300-400mL:400-600mL.

7. The TPV sealing material of claim 5, wherein, The intermediate product 2, p-aminobenzoic acid, p-toluenesulfonic acid, toluene, ethyl acetate, sodium bicarbonate solution, water and saturated sodium chloride solution in step B3 are used in a ratio of 0.2-0.4mol:0.21-0.41mol:0.02-0.04mol:200-300mL:200-250mL:200-300mL:300mL:300mL.

8. The TPV sealing material of claim 5, wherein, The thiourea, distilled water and intermediate product 3 solution in step B4 are used in a ratio of 0.1-0.2mol:350-700mL:350-700mL, and the intermediate product 3 solution is obtained by mixing intermediate product 3 and distilled water in a ratio of 0.21-0.42mol:350-700mL.

9. The TPV sealing material of claim 1, wherein, The filler is one of mica, light calcium carbonate and barium sulfate, the vulcanizing agent is bis-dipentasulfide, the vulcanization accelerator is one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate and triallyl cyanurate, and the compatibilizer is maleic anhydride grafted polyethylene.

10. A process for the preparation of the TPV sealing material according to any one of claims 1 to 9, characterized in that, The TPV sealing material is prepared by the following steps: Step S1, taking raw materials according to weight fraction, performing first plasticizing of PP resin, EPDM rubber, vulcanizing agent, vulcanization accelerator, modified heat stabilizer and modified antioxidant in a double screw extruder, to obtain semi-finished product, screw rotation speed is 500-650r / min, plasticizing temperature is 160-200℃; Step S2, performing second plasticizing of semi-finished product, polylactic acid, filler and compatibilizer in a double screw extruder, to obtain TPV sealing material, wherein, screw rotation speed is 400-500r / min, plasticizing temperature is 160-200℃.

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