High and low temperature resistant composite material and preparation process thereof

Abstract

The application discloses a high and low temperature resistant composite material and a preparation process thereof, and belongs to the technical field of water cup preparation. EVA elastomer is used as a basic raw material, modified cardanol is used as a plasticizer, phosphate ester starch subjected to plasma surface treatment is used as a reinforcing and filling material, carboxylated chitosan / surfactant / nano hydrotalcite is used as a composite intercalation agent, and vulcanizing agents, accelerators and anti-aging agents are further included. The modified cardanol is obtained by itaconic acid grafting and esterification modification treatment of cardanol, itaconic acid and ethylene glycol as raw materials. The carboxylated chitosan / surfactant / nano hydrotalcite is used for intercalation treatment of phosphate ester starch, nano hydrotalcite is used as a base material, silane coupling agent KH-550 is used for grafting nano hydrotalcite, then carboxylated chitosan and surfactant are introduced into the interlayer of hydrotalcite, and finally assembled with phosphate ester starch. The application has stable structure, excellent high temperature resistance and low temperature resistance, and can reduce the escape of the plasticizer.

Description

Technical Field

[0001] This invention relates to the field of water cup manufacturing technology, specifically to a high and low temperature resistant composite material and its manufacturing process. Background Technology

[0002] As one of the core components of a cup, the sealing ring's performance determines the cup's leak-proof effect and lifespan, and it is widely used in water cups. With the increasingly diverse usage scenarios for cups, water cups are required to withstand extreme temperature environments such as high-temperature sterilization (e.g., steam sterilization at around 150℃, boiling water) and low-temperature storage (e.g., refrigeration below -20℃, outdoor low-temperature transportation). Therefore, this has led to higher requirements for the sealing ring material's high and low temperature resistance, structural stability, and safety and environmental friendliness.

[0003] Currently, sealing ring materials still have the following problems: Taking commonly used phthalate plasticizers as an example, they tend to leach from the surface of the material during long-term use and aging, leading to a gradual decrease in the material's low-temperature flexibility and structural stability; at the same time, phthalate plasticizers also have biotoxicity, posing a threat to humans and the environment; in addition, the material is prone to softening and deformation under high-temperature conditions, and its high-temperature resistance is insufficient, directly affecting the sealing effect and the service life of the water cup.

[0004] Based on this, the present invention designs a high and low temperature resistant composite material and its preparation process to solve the above problems. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a high and low temperature resistant composite material and its preparation process.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A high- and low-temperature resistant composite material uses EVA elastomer as the base material, modified cashew nut shell powder as a plasticizer, phosphate starch ester treated with plasma as a reinforcing filler, and carboxylated chitosan / surfactant / nano-hydrotalcite as a composite intercalating agent. It also includes a vulcanizing agent, an accelerator, and an antioxidant. The modified cashew nut shell powder is obtained by grafting and esterifying itaconic acid with cashew nut shell powder, itaconic acid, and ethylene glycol. The carboxylated chitosan / surfactant / nano-hydrotalcite is used to intercalate the phosphate starch ester. Nano-hydrotalcite is used as the substrate, and the nano-hydrotalcite is grafted with the silane coupling agent KH-550. Then, carboxylated chitosan and surfactant are introduced into the interlayer of the hydrotalcite, and finally assembled with the phosphate starch ester.

[0008] Furthermore, the vulcanizing agent is DBPH, the accelerator is TBzTD, and the antioxidant is a combination of antioxidant 445 and antioxidant 1010.

[0009] To better achieve the objectives of this invention, the present invention also provides a preparation process for a high and low temperature resistant composite material, comprising the following steps: 105-135 parts by weight of EVA elastomer are fed into an internal mixer and plasticized at 55°C and 100 rpm for 2-4 minutes; then the temperature is raised to 70°C, and 6-8 parts by weight of intercalated phosphate starch are added and mixed for 3-5 minutes; then 5.8-7.5 parts by weight of modified cashew nut shell powder and 1-2 parts by weight of antioxidant are added and mixed for another 2-4 minutes; finally, 0.5-1 parts by weight of vulcanizing agent and 0.5-1 parts by weight of accelerator are added and mixed for 2-3 minutes before discharge, followed by molding, vulcanization, and cooling to obtain the composite material;

[0010] Furthermore, the plasma parameters are set as follows: power 320~350W, air flow rate 18~22 L / min, vacuum degree 400~500Pa, and processing time 100~250s.

[0011] Furthermore, the specific preparation steps of the modified cashew phenol are as follows:

[0012] (1) Preparation of itaconic acid grafted with cashew phenol: Cashew phenol and itaconic acid are mixed at a molar ratio of 1:1 and stirred at 110~115℃ for 2~2.2h. Then, 3~3.5% of p-toluenesulfonic acid of the total mass of the raw materials is added and the mixture is placed under a vacuum of -0.08~-0.085MPa and at 110~115℃ for 4~4.3h.

[0013] (2) Esterification modification of itaconic acid grafted with cashew phenol: Itaconic acid grafted with cashew phenol and ethylene glycol are mixed at a molar ratio of 1:0.5~0.6, and 0.5~0.8% of p-toluenesulfonic acid is added. First, the mixture is stirred and reacted at atmospheric pressure and 105~110℃ for 0.8~1h, with microwave assistance during the process. Then, the mixture is placed under a vacuum of -0.09~-0.095MPa and 115~120℃ for 3~4h. Finally, nitrogen gas is introduced and 0.3~0.5% of triethylamine is added to terminate the reaction, thus obtaining the modified cashew phenol plasticizer.

[0014] Furthermore, the microwave power is 250~450W.

[0015] Furthermore, the specific preparation steps for intercalated phosphate starch are as follows:

[0016] (1) Silane coupling agent KH-550 grafted nano-hydrotalcite: 5-8 parts by weight of nano-hydrotalcite were added to 100 ml of anhydrous ethanol solution of KH-550 in multiple portions and stirred at 30-32℃ for 20-30 min; then the temperature was raised to 60-65℃, and a mixture of ethanol and water was added and stirred for 2.2-3 h. After centrifugation, washing with ethanol and drying, KH-550-LDHs were obtained.

[0017] (2) Surfactant pre-intercalation: Take 5-8 parts by weight of KH-550-LDHs and put them into 100 mL of deionized water to form a KH-550-LDHs dispersion. Dissolve 1.2-2 parts by weight of sodium stearoyl lactylate in hot water to obtain an SSL solution. Slowly add the SSL solution to the KH-550-LDHs dispersion and stir at 55-60℃ for 1-2 h. After centrifugation, washing with deionized water until neutral, and drying, SSL-KH-550-LDHs is obtained.

[0018] (3) Carboxylated chitosan intercalation: Take 2-4 parts by weight of SSL-KH-550-LDHs and put them into deionized water to form an SSL-KH-550-LDHs dispersion. Dissolve 1.3-2.6 parts by weight of carboxylated chitosan in 50 mL of water to obtain a carboxylated chitosan solution.

[0019] The carboxylated chitosan solution was slowly added to the SSL-KH-550-LDHs dispersion. After the addition was complete, the pH was adjusted to 5.0-6.0, and the mixture was stirred at 50-52℃ for 3-4 hours. After centrifugation and washing with deionized water until neutral, the carboxylated chitosan-intercalated SSL-KH-550-LDHs were obtained.

[0020] (4) Assembly: Take 10-15 parts by weight of phosphate starch and put it into 200 mL of deionized water. Add 0.6-0.9 parts by weight of carboxylated chitosan-intercalated SSL-KH-550-LDHs, stir at 50-55℃ for 0.5-1 h, freeze dry at -40--50℃, then press into a sheet with a thickness of 1-2 mm, irradiate with an electron beam, and finally crush and sieve the sheet to obtain the intercalated phosphate starch.

[0021] Furthermore, the nano-hydrotalcite particles have a diameter of 50~100nm.

[0022] Furthermore, the electron beam irradiation dose is controlled at 65~80kGy, and the dose rate is 10~20kGy / h.

[0023] Compared with the prior art, the beneficial effects of this invention are as follows: structural stability: the modified cashew phenol plasticizer can be inserted into the gaps between the EVA elastomer molecular chains, and combined with the "bridging effect" of the phosphate starch treated with the composite intercalating agent, it forms a stable chemical bond connection with the EVA elastomer molecules, thereby enhancing the structural stability of the material.

[0024] High temperature resistance: Through the combined action of vulcanizing agent and accelerator, EVA elastomer molecules form a three-dimensional cross-linked network, which restricts the free movement of molecular chains at high temperatures and prevents the material from softening; the phosphate starch treated with composite intercalating agent further enhances the network density of the cross-linked structure, improving the material's high temperature resistance and stability.

[0025] Low temperature resistance: On the other hand, the long-chain alkyl groups of modified cashew phenol are inserted into the gaps between EVA elastomer molecular chains, reducing intermolecular forces; by treating phosphate starch with a composite intercalating agent, the gaps between EVA elastomer molecular chains are further increased, providing space for chain segment movement at low temperatures and maintaining low-temperature flexibility.

[0026] Reduce plasticizer release: The cross-linked structure of phosphate starch treated with composite intercalating agent is beneficial for adsorbing modified cashew phenol plasticizer, increasing the stability of modified cashew phenol plasticizer, and combined with the cross-linked network formed after vulcanization, it can effectively reduce the release of plasticizer during long-term aging. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Example 1: In some embodiments, a method for preparing a high and low temperature resistant composite material includes the following steps:

[0029] Preparation of modified cashew nut shells: (1) Preparation of itaconic acid-grafted cashew nut shells: Cashew nut shells and itaconic acid were mixed at a molar ratio of 1:1 and stirred at 110°C for 2.2 h. 3% of the total mass of the raw materials was added to p-toluenesulfonic acid and the mixture was placed under vacuum of -0.085 MPa and at 110°C for 4.3 h. (2) Esterification modification of itaconic acid-grafted cashew nut shells: Itaconic acid-grafted cashew nut shells and ethylene glycol were mixed at a molar ratio of 1:0.5. 0.8% of the total mass of the raw materials was added to p-toluenesulfonic acid and the mixture was stirred at atmospheric pressure and 105°C for 1 h. Microwave assistance (microwave power of 250 W) was used during this process. The mixture was then placed under vacuum of -0.095 MPa and at 115°C for 4 h. Finally, nitrogen gas was introduced and 0.3% of the total mass of the raw materials was added to terminate the reaction, thus obtaining the modified cashew nut shell plasticizer.

[0030] The carboxylated chitosan / surfactant / nano-hydrotalcite is used for the intercalation treatment of phosphate starch, and the specific steps are as follows:

[0031] (1) Silane coupling agent KH-550 grafted nano-hydrotalcite: 8 parts by weight of nano-hydrotalcite (particle size 50nm) were added in multiple portions to 100ml of KH-550 anhydrous ethanol solution (concentration 8%), and stirred at 30℃ for 30min; then the temperature was raised to 60℃, and 50ml of ethanol-water mixture (volume ratio of deionized water to anhydrous ethanol = 1:1) was added, and stirring was continued for 3h. After centrifugation, washing with ethanol, and drying, KH-550-LDHs were obtained.

[0032] (2) Surfactant pre-intercalation: Take 5 parts by weight of KH-550-LDHs and put them into 100 mL of deionized water to form a KH-550-LDHs dispersion. Dissolve 2 parts by weight of sodium stearoyl lactylate in 50 mL of hot water (60℃) to obtain an SSL solution. Slowly add the SSL solution to the KH-550-LDHs dispersion and stir at 55℃ for 2 h. After centrifugation, washing with deionized water until neutral and drying, SSL-KH-550-LDHs is obtained.

[0033] (3) Carboxylated chitosan intercalation: Take 2 parts by weight of SSL-KH-550-LDHs and put them into 100mL of deionized water to form an SSL-KH-550-LDHs dispersion. Dissolve 2.6 parts by weight of carboxylated chitosan in 50mL of water to obtain a carboxylated chitosan solution.

[0034] The carboxylated chitosan solution was slowly added to the SSL-KH-550-LDHs dispersion. After the addition was complete, the pH was adjusted to 5.0, and the mixture was stirred at 52°C for 3 hours. After centrifugation and washing with deionized water until neutral, the carboxylated chitosan-intercalated SSL-KH-550-LDHs were obtained.

[0035] (4) Assembly: Take 10 parts by weight of phosphate starch and put it into 200 mL of deionized water. Add 0.9 parts by weight of carboxylated chitosan-intercalated SSL-KH-550-LDHs, stir at 50℃ for 1 h, freeze dry at -40℃, and then press it into a sheet with a thickness of 2 mm. Irradiate it with an electron beam, with the irradiation dose controlled at 65 kGy and the dose rate at 20 kGy / h. Finally, crush the sheet and sieve it through 200 mesh to obtain the intercalated phosphate starch.

[0036] 105 parts by weight of EVA elastomer were added to an internal mixer and plasticized at 55°C and 100 rpm for 4 minutes. Then, the temperature was raised to 70°C, and 6 parts by weight of intercalated phosphate starch were added and mixed for 5 minutes. Then, 5.8 parts by weight of plasticizer and 2 parts by weight of antioxidant (weight ratio: antioxidant 445: antioxidant 1010 = 3:1) were added and mixed for another 2 minutes. Finally, 0.5 parts by weight of vulcanizing agent (DBPH) and 0.5 parts by weight of accelerator (TBzTD) were added and mixed for 3 minutes before being discharged. The mixture was then molded, vulcanized (150°C × 10MPa × 18 minutes), and cooled to obtain the composite material.

[0037] Example 2: In some embodiments, a method for preparing a high and low temperature resistant composite material includes the following steps:

[0038] Preparation of modified cashew nut shell: (1) Preparation of itaconic acid grafted cashew nut shell: Cashew nut shell and itaconic acid are mixed at a molar ratio of 1:1 and stirred at 115°C for 2 hours. Then, 3.5% of the total mass of the raw materials is added to p-toluenesulfonic acid and the mixture is placed under vacuum of -0.08MPa and at 115°C for 4 hours. (2) Esterification modification of itaconic acid grafted cashew nut shell: Itaconic acid grafted cashew nut shell and ethylene glycol are mixed at a molar ratio of 1:0.6 and 0.5% of the total mass of the raw materials is added to p-toluenesulfonic acid. The mixture is first stirred at atmospheric pressure and 110°C for 0.8 hours. Microwave assistance (microwave power of 450W) is used during this process. Then, the mixture is placed under vacuum of -0.09MPa and at 120°C for 3 hours. Finally, nitrogen gas is introduced and 0.5% of the total mass of the raw materials is added to terminate the reaction, thus obtaining the modified cashew nut shell plasticizer.

[0039] The carboxylated chitosan / surfactant / nano-hydrotalcite is used for the intercalation treatment of phosphate starch, and the specific steps are as follows:

[0040] (1) Silane coupling agent KH-550 grafted nano-hydrotalcite: 5 parts by weight of nano-hydrotalcite (particle size 100nm) were added in multiple portions to 100ml of KH-550 anhydrous ethanol solution (concentration 5%), and stirred at 32℃ for 20min; then the temperature was raised to 65℃, and 50ml of ethanol-water mixture (volume ratio of deionized water to anhydrous ethanol = 1:1) was added, and stirring was continued for 2.2h. After centrifugation, washing with ethanol, and drying, KH-550-LDHs were obtained.

[0041] (2) Surfactant pre-intercalation: Take 8 parts by weight of KH-550-LDHs and put them into 100 mL of deionized water to form a KH-550-LDHs dispersion. Dissolve 1.2 parts by weight of sodium stearoyl lactylate in 50 mL of hot water (60 °C) to obtain an SSL solution. Slowly add the SSL solution to the KH-550-LDHs dispersion and stir at 60 °C for 1 h. After centrifugation, washing with deionized water until neutral and drying, SSL-KH-550-LDHs is obtained.

[0042] (3) Carboxylated chitosan intercalation: Take 4 parts by weight of SSL-KH-550-LDHs and put them into 100mL of deionized water to form an SSL-KH-550-LDHs dispersion. Dissolve 1.3 parts by weight of carboxylated chitosan in 50mL of water to obtain a carboxylated chitosan solution.

[0043] The carboxylated chitosan solution was slowly added to the SSL-KH-550-LDHs dispersion. After the addition was complete, the pH was adjusted to 6.0, and the mixture was stirred at 50°C for 4 hours. After centrifugation and washing with deionized water until neutral, the SSL-KH-550-LDHs with carboxylated chitosan intercalation were obtained.

[0044] (4) Assembly: Take 15 parts by weight of phosphate starch and put it into 200 mL of deionized water. Add 0.6 parts by weight of carboxylated chitosan-intercalated SSL-KH-550-LDHs, stir at 55℃ for 0.5 h, freeze dry at -50℃, and then press it into a sheet with a thickness of 1 mm. Irradiate it with an electron beam, with the irradiation dose controlled at 80 kGy and the dose rate at 10 kGy / h. Finally, crush the sheet and sieve it through 200 mesh to obtain the intercalated phosphate starch.

[0045] 135 parts by weight of EVA elastomer were added to an internal mixer and plasticized at 55°C and 100 rpm for 2 minutes. Then, the temperature was raised to 70°C, and 8 parts by weight of intercalated phosphate starch were added and mixed for 3 minutes. Then, 7.5 parts by weight of plasticizer and 1 part by weight of antioxidant (weight ratio: antioxidant 445: antioxidant 1010 = 3:1) were added and mixed for another 4 minutes. Finally, 1 part by weight of vulcanizing agent (DBPH) and 1 part by weight of accelerator (TBzTD) were added and mixed for 2 minutes before discharge. The mixture was then molded, vulcanized (150°C × 10MPa × 18 minutes), and cooled to obtain the composite material.

[0046] Example 3: In some embodiments, a method for preparing a high and low temperature resistant composite material includes the following steps:

[0047] Preparation of modified cashew nut shell: (1) Preparation of itaconic acid grafted cashew nut shell: Cashew nut shell and itaconic acid are mixed at a molar ratio of 1:1 and stirred at 112°C for 2 hours. Then, 3.1% of the total mass of the raw materials is added to p-toluenesulfonic acid and the mixture is placed under vacuum of -0.082 MPa and at 112°C for 4.1 hours. (2) Esterification modification of itaconic acid grafted cashew nut shell: Itaconic acid grafted cashew nut shell and ethylene glycol are mixed at a molar ratio of 1:0.55 and 0.6% of the total mass of the raw materials is added to p-toluenesulfonic acid. The mixture is first stirred at atmospheric pressure and 108°C for 0.9 hours. Microwave assistance (microwave power of 300W) is used during this process. Then, the mixture is placed under vacuum of -0.091 MPa and at 117°C for 3.2 hours. Finally, nitrogen gas is introduced and 0.4% of the total mass of the raw materials is added to terminate the reaction, thus obtaining the modified cashew nut shell plasticizer.

[0048] The carboxylated chitosan / surfactant / nano-hydrotalcite is used for the intercalation treatment of phosphate starch, and the specific steps are as follows:

[0049] (1) Silane coupling agent KH-550 grafted nano-hydrotalcite: 5 parts by weight of nano-hydrotalcite (particle size 60nm) were added in multiple portions to 100ml of KH-550 anhydrous ethanol solution (concentration 7%), and stirred at 31℃ for 23min; then the temperature was raised to 62℃, and 50ml of ethanol-water mixture (volume ratio of deionized water to anhydrous ethanol = 1:1) was added, and stirring was continued for 2.5h. After centrifugation, washing with ethanol, and drying, KH-550-LDHs were obtained.

[0050] (2) Surfactant pre-intercalation: Take 6 parts by weight of KH-550-LDHs and put them into 100 mL of deionized water to form a KH-550-LDHs dispersion. Dissolve 1.3 parts by weight of sodium stearoyl lactylate in 50 mL of hot water (60℃) to obtain an SSL solution. Slowly add the SSL solution to the KH-550-LDHs dispersion and stir at 58℃ for 1.2 h. After centrifugation, washing with deionized water until neutral and drying, SSL-KH-550-LDHs is obtained.

[0051] (3) Carboxylated chitosan intercalation: Take 3 parts by weight of SSL-KH-550-LDHs and put them into 100mL of deionized water to form SSL-KH-550-LDHs dispersion. Dissolve 2 parts by weight of carboxylated chitosan in 50mL of water to obtain carboxylated chitosan solution.

[0052] The carboxylated chitosan solution was slowly added to the SSL-KH-550-LDHs dispersion. After the addition was complete, the pH was adjusted to 5.5, and the mixture was stirred at 51.5℃ for 3.3 h. After centrifugation and washing with deionized water until neutral, the carboxylated chitosan-intercalated SSL-KH-550-LDHs were obtained.

[0053] (4) Assembly: Take 13 parts by weight of phosphate starch and put it into 200 mL of deionized water. Add 0.7 parts by weight of carboxylated chitosan-intercalated SSL-KH-550-LDHs, stir at 52℃ for 0.6 h, freeze dry at -45℃, and then press it into a sheet with a thickness of 1.6 mm. Irradiate it with an electron beam, with the irradiation dose controlled at 70 kGy and the dose rate at 15 kGy / h. Finally, crush the sheet and sieve it through 200 mesh to obtain the intercalated phosphate starch.

[0054] 125 parts by weight of EVA elastomer were added to an internal mixer and plasticized at 55°C and 100 rpm for 3 minutes. Then, the temperature was raised to 70°C, and 7 parts by weight of intercalated phosphate starch were added and mixed for 4 minutes. Then, 6 parts by weight of plasticizer and 1.2 parts by weight of antioxidant (weight ratio: antioxidant 445: antioxidant 1010 = 3:1) were added and mixed for another 2.5 minutes. Finally, 0.6 parts by weight of vulcanizing agent (DBPH) and 0.7 parts by weight of accelerator (TBzTD) were added and mixed for another 2.5 minutes before discharge. The mixture was then molded, vulcanized (150°C × 10MPa × 18 minutes), and cooled to obtain the composite material.

[0055] Comparative Example 1: The difference from Example 1 is that the modified cashew phenol was replaced with an equal amount of prepared cashew phenol, that is, the prepared cashew phenol was not modified.

[0056] Comparative Example 2: The difference from Example 1 is that the surfactant / nano-hydrotalcite is used for intercalation treatment of phosphate starch, and the specific steps are as follows:

[0057] (1) Silane coupling agent KH-550 grafted nano-hydrotalcite: 8 parts by weight of nano-hydrotalcite (particle size 50nm) were added in multiple portions to 100ml of KH-550 anhydrous ethanol solution (concentration 8%), and stirred at 30℃ for 30min; then the temperature was raised to 60℃, and 50ml of ethanol-water mixture (volume ratio of deionized water to anhydrous ethanol = 1:1) was added, and stirring was continued for 3h. After centrifugation, washing with ethanol, and drying, KH-550-LDHs were obtained.

[0058] (2) Surfactant pre-intercalation: Take 5 parts by weight of KH-550-LDHs and put them into 100 mL of deionized water to form a KH-550-LDHs dispersion. Dissolve 2 parts by weight of sodium stearoyl lactylate in 50 mL of hot water (60℃) to obtain an SSL solution. Slowly add the SSL solution to the KH-550-LDHs dispersion and stir at 55℃ for 2 h. After centrifugation, washing with deionized water until neutral and drying, SSL-KH-550-LDHs is obtained.

[0059] (3) Assembly: Take 10 parts by weight of phosphate starch and put it into 200 mL of deionized water. Add 0.9 parts by weight of SSL-KH-550-LDHs, stir at 50℃ for 1 h, freeze dry at -40℃, and then press it into a sheet with a thickness of 2 mm. Irradiate it with an electron beam, with the irradiation dose controlled at 65 kGy and the dose rate at 20 kGy / h. Finally, crush the sheet and sieve it through 200 mesh to obtain the intercalated phosphate starch.

[0060] Comparative Example 3: The difference from Example 1 is that the carboxylated chitosan / nano-hydrotalcite is used for intercalation treatment of phosphate starch, and the specific steps are as follows:

[0061] (1) Silane coupling agent KH-550 grafted nano-hydrotalcite: 8 parts by weight of nano-hydrotalcite (particle size 50nm) were added in multiple portions to 100ml of KH-550 anhydrous ethanol solution (concentration 8%), and stirred at 30℃ for 30min; then the temperature was raised to 60℃, and 50ml of ethanol-water mixture (volume ratio of deionized water to anhydrous ethanol = 1:1) was added, and stirring was continued for 3h. After centrifugation, washing with ethanol, and drying, KH-550-LDHs were obtained.

[0062] (2) Carboxylated chitosan intercalation: Take 2 parts by weight of KH-550-LDHs and put them into 100 mL of deionized water to form a KH-550-LDHs dispersion. Dissolve 2.6 parts by weight of carboxylated chitosan in 50 mL of water to obtain a carboxylated chitosan solution.

[0063] The carboxylated chitosan solution was slowly added to the KH-550-LDHs dispersion. After the addition was complete, the pH was adjusted to 5.0, and the mixture was stirred at 52°C for 3 hours. After centrifugation and washing with deionized water until neutral, the carboxylated chitosan-intercalated KH-550-LDHs were obtained.

[0064] (3) Assembly: Take 10 parts by weight of phosphate starch and put it into 200 mL of deionized water. Add 0.9 parts by weight of carboxylated chitosan-intercalated KH-550-LDHs, stir at 50℃ for 1 h, freeze dry at -40℃, and then press it into a sheet with a thickness of 2 mm. Irradiate it with an electron beam, with the irradiation dose controlled at 65 kGy and the dose rate at 20 kGy / h. Finally, crush the sheet and sieve it through 200 mesh to obtain the intercalated phosphate starch.

[0065] Comparative Example 4: Phosphate starch without plasma surface treatment was used as a reinforcing filler.

[0066] Verification experiments: The composite materials of Examples 1-3 and Comparative Examples 1-4 were subjected to the following tests, and the results are shown in Table 1:

[0067] Tensile strength (MPa) and elongation at break (%) of composite materials (ASTM D412-06a).

[0068] Glass transition temperature Tg (GB / T 19466.2-2004), ℃.

[0069] Low-temperature compression set (GB / T 7759.2-2014), -40℃×24h, 25% compression set.

[0070] Tensile property retention rate after high-temperature heat aging: The tensile strength of the specimens before and after aging (hot air aging at 150℃ for 72h) was determined according to GB / T 3512-2014 (GB / T528-2009), and the tensile strength retention rate was calculated.

[0071] Plasticizer leaching at 150℃ (GB 4806.11-2016), mg / dm³ 2 .

[0072] Table 1 Test Results

[0073] experiment Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Tensile strength 13.8 12.9 13.3 9.9 10.8 11.6 12.3 Elongation at break 575 510 558 360 425 437 465 Glass transition temperature Tg -45 -44 -42 -38 -41 -42 -44 Low temperature compression set 7.5 8.8 7.9 16.3 13.5 12.1 7.4 Tensile property retention rate after high temperature heat aging 91 89 92 62.3 71.5 77.9 90 Plasticizer release at 150℃ 0.045 0.041 0.050 0.26 0.13 0.10 0.053

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite material resistant to high and low temperatures, characterized in that, Using EVA elastomer as the base material, modified cashew nut shell powder as the plasticizer, plasma-treated phosphate starch as the reinforcing filler, and carboxylated chitosan / surfactant / nano-hydrotalcite as the composite intercalating agent, the product also includes vulcanizing agents, accelerators, and antioxidants. The modified cashew nut shell powder is obtained by grafting and esterifying itaconic acid with cashew nut shell powder, itaconic acid, and ethylene glycol. The carboxylated chitosan / surfactant / nano-hydrotalcite is used to intercalate the phosphate starch. Using nano-hydrotalcite as the substrate, the nano-hydrotalcite is grafted with the silane coupling agent KH-550, then the carboxylated chitosan and surfactant are introduced into the interlayer of the hydrotalcite, and finally assembled with the phosphate starch. 105-135 parts by weight of EVA elastomer were put into an internal mixer and plasticized at 55°C and 100 / min for 2-4 min. The temperature is then raised to 70°C, and 6-8 parts by weight of intercalated phosphate starch are added and mixed for 3-5 minutes. Then, 5.8-7.5 parts by weight of modified cashew phenol and 1-2 parts by weight of antioxidant are added and mixed for another 2-4 minutes. Finally, 0.5-1 parts by weight of vulcanizing agent and 0.5-1 parts by weight of accelerator are added and mixed for 2-3 minutes before being discharged. The mixture is then molded, vulcanized, and cooled to obtain the composite material.

2. The high and low temperature resistant composite material according to claim 1, characterized in that, The vulcanizing agent is DBPH, the accelerator is TBzTD, and the antioxidant is a combination of antioxidant 445 and antioxidant 1010.

3. A preparation process for a high and low temperature resistant composite material according to claim 1 or 2, characterized in that, The process includes the following steps: 105-135 parts by weight of EVA elastomer are fed into an internal mixer and plasticized at 55°C and 100 rpm for 2-4 minutes; The temperature is then raised to 70°C, and 6-8 parts by weight of intercalated phosphate starch are added and mixed for 3-5 minutes. Then, 5.8-7.5 parts by weight of modified cashew phenol and antioxidant are added and mixed for another 2-4 minutes. Finally, 0.5-1 parts by weight of vulcanizing agent and 0.5-1 parts by weight of accelerator are added and mixed for 2-3 minutes before being discharged. The mixture is then molded, vulcanized, and cooled to obtain the composite material.

4. The preparation process of the high and low temperature resistant composite material according to claim 3, characterized in that, Plasma parameter settings: power 320~350W, air flow rate 18~22 L / min, vacuum degree 400~500Pa, processing time 100~250s.

5. The preparation process of the high and low temperature resistant composite material according to claim 3, characterized in that, The amount of antioxidant added is 1-2 parts by weight, the amount of vulcanizing agent added is 1-2 parts by weight, and the amount of accelerator added is 0.5-1 parts by weight.

6. The preparation process of the high and low temperature resistant composite material according to claim 3, characterized in that, The specific preparation steps of the modified cashew phenol are as follows: (1) Preparation of itaconic acid grafted with cashew phenol: Cashew phenol and itaconic acid are mixed at a molar ratio of 1:1 and stirred at 110~115℃ for 2~2.2h. Then, 3~3.5% of p-toluenesulfonic acid of the total mass of the raw materials is added and the mixture is placed under a vacuum of -0.08~-0.085MPa and at 110~115℃ for 4~4.3h. (2) Esterification modification of itaconic acid grafted with cashew phenol: Itaconic acid grafted with cashew phenol and ethylene glycol are mixed at a molar ratio of 1:0.5~0.6, and 0.5~0.8% of p-toluenesulfonic acid is added. First, the mixture is stirred and reacted at atmospheric pressure and 105~110℃ for 0.8~1h, with microwave assistance during the process. Then, the mixture is placed under a vacuum of -0.09~-0.095MPa and 115~120℃ for 3~4h. Finally, nitrogen gas is introduced and 0.3~0.5% of triethylamine is added to terminate the reaction, thus obtaining the modified cashew phenol plasticizer.

7. The preparation process of the high and low temperature resistant composite material according to claim 6, characterized in that, The microwave power is 250~450W.

8. The preparation process of the high and low temperature resistant composite material according to claim 3, characterized in that, The specific preparation steps of intercalated phosphate starch are as follows: (1) Silane coupling agent KH-550 grafted nano-hydrotalcite: 5-8 parts by weight of nano-hydrotalcite were added to an anhydrous ethanol solution of KH-550 in multiple portions and stirred at 30-32℃ for 20-30 min; then the temperature was raised to 60-65℃, and a mixture of ethanol and water was added. The mixture was stirred for 2.2-3 h. After centrifugation, washing with ethanol and drying, KH-550-LDHs were obtained. (2) Surfactant pre-intercalation: Take 5-8 parts by weight of KH-550-LDHs and put them into deionized water to form a KH-550-LDHs dispersion. Dissolve 1.2-2 parts by weight of sodium stearoyl lactylate in hot water to obtain an SSL solution. Slowly add the SSL solution to the KH-550-LDHs dispersion and stir at 55-60℃ for 1-2 hours. After centrifugation, washing with deionized water until neutral, and drying, SSL-KH-550-LDHs is obtained. (3) Carboxylated chitosan intercalation: Take 2-4 parts by weight of SSL-KH-550-LDHs and put them into deionized water to form an SSL-KH-550-LDHs dispersion. Dissolve 1.3-2.6 parts by weight of carboxylated chitosan in water to obtain a carboxylated chitosan solution. The carboxylated chitosan solution was slowly added to the SSL-KH-550-LDHs dispersion. After the addition was complete, the pH was adjusted to 5.0-6.0, and the mixture was stirred at 50-52℃ for 3-4 hours. After centrifugation and washing with deionized water until neutral, the carboxylated chitosan-intercalated SSL-KH-550-LDHs were obtained. (4) Assembly: Take 10-15 parts by weight of phosphate starch and put it into deionized water. Add 0.6-0.9 parts by weight of carboxylated chitosan-intercalated SSL-KH-550-LDHs, stir at 50-55℃ for 0.5-1h, freeze dry at -40--50℃, then press into a sheet with a thickness of 1-2mm, irradiate with an electron beam, and finally crush and sieve the sheet to obtain the intercalated phosphate starch.

9. The preparation process of the high and low temperature resistant composite material according to claim 8, characterized in that, The nano-hydrotalcite has a particle size of 50~100nm.

10. The preparation process of the high and low temperature resistant composite material according to claim 9, characterized in that, The electron beam irradiation dose is controlled at 65~80kGy, and the dose rate is 10~20kGy / h.