A bio-based TPV composite material and preparation method thereof

Abstract

The present invention discloses a bio-based TPV composite material and a preparation method thereof, belonging to the technical field of TPV composite material preparation. The invention uses polylactic acid as the plastic phase, bio-based itaconate rubber and bio-based ethylene-vinyl acetate copolymer as the rubber phase, maleic anhydride grafted cardanol and ethylene-acrylic acid copolymer as a composite compatibilizer, and titanate coupling agent-modified core-shell particles as a reinforcing agent. The bio-based PLA / Bio-ItBR / EVA TPV is prepared by a dynamic vulcanization process using dicumyl peroxide combined with electron beam radiation initiation. The product has medium hardness, medium to high tensile strength, excellent ductility and high elasticity, good elastic memory and resistance to compression deformation. The present invention improves the compatibility between the plastic phase and the rubber phase, reducing the phase separation problem caused by polarity differences. The dynamic vulcanization process using dicumyl peroxide combined with electron beam radiation initiation can form a uniform cross-linked network and improve the stability of material properties.

Description

Technical Field

[0001] The present invention relates to the technical field of TPV composite material preparation, and in particular to a bio-based TPV composite material and a preparation method thereof. Background Art

[0002] TPV composite materials are thermoplastic vulcanizates, which are usually composed of a continuous phase of thermoplastic resin (such as polypropylene (PP)) and a dispersed phase of vulcanized rubber (such as ethylene propylene diene monomer (EPDM)).

[0003] Traditional TPV raw materials are mostly derived from fossil resources or are derivatives of fossil resources. Due to the shortage of fossil resources and severe environmental problems, new ways to reduce dependence on fossil resources are urgently needed. In this context, the application of bio-based materials in the development of bio-based TPV materials has become a key path to reducing dependence on fossil resources due to their advantages such as green, environmentally friendly, biodegradable, and renewable raw materials.

[0004] For example, CN118063972A discloses a bio-based TPV composite material for automotive use and its preparation method. The composite material comprises the following raw materials by weight: 10-35 parts bio-based PP, 25-50 parts bio-based EPDM, 35-50 parts bio-soybean oil, 1-10 parts biomass filler (white carbon black), 1-5 parts masterbatch, 1-10 parts composite vulcanizer, 1-5 parts composite stabilizer, and 1-10 parts lubricant. The bio-based PP, bio-based EPDM, biomass filler, masterbatch, and bio-soybean oil are fully plasticized within a screw before being combined with additives such as the composite vulcanizer and composite stabilizer, and then extruded into pellets. A composite vulcanization system of tert-butyl peroxyacetate and di-tert-butyl peroxide is employed. The vulcanization reaction is initiated with tert-butyl peroxyacetate, followed by cross-linking of any remaining incompletely vulcanized components by di-tert-butyl peroxide through its own molecular chains. This promotes uniform dispersion of the components within the material, increases the crosslinking density, and thus improves the elastic properties of the bio-based TPV material.

[0005] However, it has the following defects:

[0006] (1) First, the amount of bio-soybean oil used is high, and its polarity is very different from that of non-polar bio-based PP / EPDM. When used at high temperature for a long time, oil is easily precipitated, which contaminates the components and accelerates the aging of the rubber phase.

[0007] (2) Secondly, the surface of biomass filler (silica) is rich in silanol groups and is prone to forming agglomerates. The process of plasticizing first and then adding additives is adopted. Silica is difficult to disperse evenly in the high viscosity melt, resulting in unstable mechanical properties of bio-based TPV materials.

[0008] Based on this, the present invention designs a bio-based TPV composite material and a preparation method thereof to solve the above problems. Summary of the Invention

[0009] In view of the above-mentioned shortcomings of the prior art, the present invention provides a bio-based TPV composite material and a preparation method thereof.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0011] A method for preparing a bio-based TPV composite material, comprising: using polylactic acid as a plastic phase, bio-based itaconate rubber and bio-based ethylene-vinyl acetate copolymer as a rubber phase, maleic anhydride-grafted cardanol and ethylene-acrylic acid copolymer as a composite compatibilizer, adding 6-8.8% of the total mass of the plastic phase and rubber phase to titanate coupling agent-modified core-shell particles as a reinforcing agent, and using dicumyl peroxide combined with electron beam radiation initiation to prepare bio-based PLA / Bio-ItBR / EVA through a dynamic vulcanization process. TPV: First, place the rubber phase and compatibilizer in an open mill at 30-45°C, slowly add the reinforcing agent that has been microwaved in advance, and mix for 3-5 minutes until there are no obvious particles. Then, add 1 / 2-1 / 3 of the total mass of dicumyl peroxide and mix for 1-2 minutes to obtain a blended rubber; heat the HAAKE torque rheometer to 160.5-162.8°C, adjust the speed to 80-100 r / min, add the plastic phase and melt it for 4.5-6 minutes, add the remaining dicumyl peroxide and the blended rubber and perform dynamic vulcanization for 6-7.5 minutes. At the same time, turn on the electron beam radiation, control the dose rate at 8-10 kGy / min, and the total dose at 15-20 kGy. The radiation time is synchronized with the dynamic vulcanization time.

[0012] Furthermore, the preparation method of the maleic anhydride grafted cardanol is as follows: cardanol and maleic anhydride are mixed in a mass ratio of 4 to 5:1, stirred and reacted at 95 to 98°C for 1.8 to 2 hours, 5 to 5.8% of the total mass of the raw materials is added with p-toluenesulfonic acid, and then placed in a vacuum degree of -0.08 to -0.085 MPa and 101 to 105°C for 3 to 3.5 hours.

[0013] Furthermore, the preparation method of the titanate coupling agent modified core-shell particles is as follows: corn starch, ethyl acetate, acryloyl chloride and stearyl chloride are weighed in a weight ratio of 75-78: 243-248: 2.8-3.2: 2.8-3.2, pyridine (2.2-3.3% of the total weight of the above raw materials) is used as a catalyst, and the esterification reaction is carried out for 1.7-2 hours to obtain esterified starch; 8-10 parts by weight of the esterified starch is added into 8-10 times the weight of water to obtain a gelatinized solution, the temperature is increased to 82-85°C, and 22-23 parts by weight of propylene glycol are added. Parts of ethyl acrylate and 0.1-0.3 parts by mass of titanate coupling agent are fully stirred, and then 0.7-1 parts by mass of 5% potassium persulfate aqueous solution are added, and the reaction is stirred at 200-300 r / min for 6.5-7 hours; then the temperature is lowered to 55-60°C, and 0.5-0.7% by mass of glycidyl methacrylate of the total mass of the reactants is added, and the temperature is first raised to 70-75°C and stirred for 0.5-1 hour, and then raised to 78-80°C and stirred for 1-1.8 hours. The obtained product is subjected to demulsification treatment and dried.

[0014] Furthermore, the microwave radiation parameters are: microwave power of 400~600W, temperature of 85~90℃, and time of 30~50s.

[0015] Furthermore, 0.2 to 0.3 parts by mass of dicumyl peroxide is added to every 100 parts by mass of the rubber phase.

[0016] Furthermore, 2 to 3 parts by mass of maleic anhydride-grafted cardanol is added to every 100 parts by mass of the rubber phase.

[0017] Furthermore, 1 to 2 parts by mass of ethylene-acrylic acid copolymer is added to every 100 parts by mass of the rubber phase.

[0018] Furthermore, the mass ratio of the rubber phase to the plastic phase is 40~45:55~60.

[0019] In order to better achieve the purpose of the present invention, the present invention also provides a bio-based TPV composite material prepared by the above-mentioned preparation method.

[0020] Furthermore, the bio-based TPV composite material has a Shore hardness of 62~65 A, a tensile strength of 10.5~13.3 MPa, an elongation at break of 459.7~488.6%, and a compression set of 27~29%.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the bio-based PLA / Bio-ItBR / EVATPV prepared by the present invention has medium hardness, medium to high tensile strength, excellent ductility and high elasticity, good elastic memory and resistance to compression deformation, and can be used for the preparation of sealing products.

[0022] The present invention uses polylactic acid as the plastic phase, bio-based itaconate rubber and bio-based ethylene-vinyl acetate copolymer as the rubber phase, maleic anhydride-grafted cardanol and ethylene-acrylic acid copolymer as a composite compatibilizer, and titanate coupling agent-modified core-shell particles as a reinforcing agent, adding 6-8.8% of the total mass of the plastic and rubber phases. The bio-based PLA / Bio-ItBR / EVA TPV is prepared using a dynamic vulcanization process using dicumyl peroxide combined with electron beam radiation initiation. This improves the compatibility between the plastic and rubber phases, reduces phase separation problems caused by polarity differences, and avoids high-temperature precipitation similar to bio-soybean oil, thereby preventing component contamination and accelerating rubber phase aging. The present invention uses dicumyl peroxide combined with an electron beam radiation-induced dynamic vulcanization process to form a uniform cross-linked network, improving the stability of material properties. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in 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 part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Example 1: A method for preparing a bio-based TPV composite material, comprising the following steps:

[0025] Step a: Preparation of maleic anhydride-grafted cardanol: Cardanol and maleic anhydride were mixed in a mass ratio of 4:1, stirred and reacted at 98°C for 1.8h, p-toluenesulfonic acid (5.8% of the total mass of the raw materials) was added, and the mixture was placed in a vacuum of -0.08MPa and 105°C for 3h. The preparation method of titanate coupling agent modified core-shell particles is as follows: corn starch, ethyl acetate, acryloyl chloride and stearyl chloride are weighed in a weight ratio of 75:248:2.8:2.8, pyridine (2.2% of the total weight of the above raw materials) is used as a catalyst, and an esterification reaction is carried out for 2 hours to obtain esterified starch (ES); 8 parts by weight of the esterified starch is added into 10 times the weight of water to obtain a gelatinized liquid, the temperature is increased to 82°C, 23 parts by weight of ethyl acrylate and 0.1 parts by weight of a titanate coupling agent are added, and the mixture is thoroughly stirred, and then 1 part by weight of a 5% potassium persulfate aqueous solution is added, and the mixture is stirred at 200 r / min for 7 hours; then the temperature is lowered to 55°C, and glycidyl methacrylate (GMA) (0.7% of the total weight of the reactants) is added, the temperature is first raised to 70°C and stirred for 1 hour, and then the temperature is raised to 78°C and stirred for 1.8 hours, and the obtained product is subjected to demulsification treatment and dried.

[0026] Step b: 55 parts by mass of polylactic acid (PLA) was used as the plastic phase, 30 parts by mass of bio-based itaconate rubber (Bio-ItBR) and 10 parts by mass of bio-based ethylene-vinyl acetate copolymer (EVA) were used as the rubber phase, maleic anhydride grafted cardanol (3 parts by mass of maleic anhydride grafted cardanol was added to every 100 parts by mass of the rubber phase) and ethylene-acrylic acid copolymer (EAA) (1 part by mass of EAA was added to every 100 parts by mass of the rubber phase) were used as composite compatibilizers, 8.8% of the total mass of the plastic phase and the rubber phase was added as a titanate coupling agent-modified core-shell particles as a reinforcing agent, and dicumyl peroxide (DCP initiator) (0.2 parts by mass of DCP initiator was added to every 100 parts by mass of the rubber phase) was used in combination with electron beam radiation initiation to prepare bio-based PLA / Bio-ItBR / EVA by a dynamic vulcanization process. TPV: First, the rubber phase and compatibilizer were placed in an open mill at 45°C, and the reinforcing agent that had been microwave-irradiated (microwave power of 400W, temperature of 90°C, time of 30s) was slowly added and mixed for 5 minutes until no obvious particles were present. Then, 1 / 2 of the total mass of dicumyl peroxide was added and mixed for 2 minutes to obtain a blended rubber. The HAAKE torque rheometer was heated to 160.5°C and the speed was adjusted to 100r / min. After adding the plastic phase, it was melted for 4.5 minutes. The remaining dicumyl peroxide and the blended rubber were added and dynamically vulcanized for 7.5 minutes. At the same time, electron beam radiation was turned on, the dose rate was controlled at 8 kGy / min, and the total dose was controlled at 20 kGy. The radiation time was synchronized with the dynamic vulcanization time to accelerate the decomposition of DCP to produce free radicals. At the same time, the electron beam triggered the breakage of the rubber molecular chain, realizing the synergistic effect of "thermal initiation + radiation initiation".

[0027] Example 2: A method for preparing a bio-based TPV composite material, comprising the following steps:

[0028] Step a: Preparation of maleic anhydride-grafted cardanol: Cardanol and maleic anhydride were mixed in a mass ratio of 5:1, stirred and reacted at 95°C for 2 hours, and p-toluenesulfonic acid (5% by mass of the total raw material) was added, followed by reaction at a vacuum degree of -0.085 MPa and 101°C for 3.5 hours. The preparation method of titanate coupling agent modified core-shell particles is as follows: corn starch, ethyl acetate, acryloyl chloride and stearyl chloride are weighed in a weight ratio of 78:243:3.2:2.8, pyridine (3.3% of the total weight of the above raw materials) is used as a catalyst, and an esterification reaction is carried out for 1.7 hours to obtain esterified starch (ES); 10 parts by weight of the esterified starch is added into 8 times the weight of water to obtain a gelatinized liquid, the temperature is increased to 85°C, 22 parts by weight of ethyl acrylate and 0.3 parts by weight of a titanate coupling agent are added, and the mixture is thoroughly stirred, and then 0.7 parts by weight of a 5% potassium persulfate aqueous solution is added, and the mixture is stirred at 300 r / min for 6.5 hours; then the temperature is lowered to 60°C, glycidyl methacrylate (GMA) (0.5% of the total weight of the reactants) is added, the temperature is first increased to 75°C and stirred for 0.5 hours, and then increased to 80°C and stirred for 1 hour, and the obtained product is subjected to demulsification treatment and dried.

[0029] Step b: 60 parts by mass of polylactic acid (PLA) was used as the plastic phase, 25 parts by mass of bio-based itaconate rubber (Bio-ItBR) and 20 parts by mass of bio-based ethylene-vinyl acetate copolymer (EVA) were used as the rubber phase, maleic anhydride grafted cardanol (2 parts by mass of maleic anhydride grafted cardanol was added to every 100 parts by mass of the rubber phase) and ethylene-acrylic acid copolymer (EAA) (2 parts by mass of EAA was added to every 100 parts by mass of the rubber phase) were used as composite compatibilizers, 6% of the total mass of the plastic phase and the rubber phase was added as a titanate coupling agent-modified core-shell particles as a reinforcing agent, and dicumyl peroxide (DCP initiator) (0.3 parts by mass of DCP initiator was added to every 100 parts by mass of the rubber phase) was used in combination with electron beam radiation initiation to prepare bio-based PLA / Bio-ItBR / EVA by a dynamic vulcanization process. TPV: First, the rubber phase and the compatibilizer were placed in an open mill at 30°C, and the reinforcing agent that had been irradiated with microwaves (microwave power of 600W, temperature of 85°C, time of 50s) was slowly added and mixed for 3 minutes until no obvious particles were present. Then, 1 / 3 of the total mass of dicumyl peroxide was added and mixed for 1 minute to obtain a rubber blend. The HAAKE torque rheometer was heated to 162.8°C and the speed was adjusted to 80r / min. After the plastic phase was added, it was melted for 6 minutes. The remaining dicumyl peroxide and the rubber blend were added and dynamically vulcanized for 6 minutes. At the same time, electron beam radiation was turned on, the dose rate was controlled at 10kGy / min, and the total dose was controlled at 15 kGy. The radiation time was synchronized with the dynamic vulcanization time to accelerate the decomposition of DCP to produce free radicals. At the same time, the electron beam triggered the breakage of the rubber molecular chain, realizing the synergistic effect of "thermal initiation + radiation initiation".

[0030] Example 3: A method for preparing a bio-based TPV composite material, comprising the following steps:

[0031] Step a: Preparation of maleic anhydride-grafted cardanol: Cardanol and maleic anhydride were mixed in a mass ratio of 4.5:1, stirred and reacted at 96°C for 1.9 hours, and p-toluenesulfonic acid (5.5% of the total mass of the raw materials) was added, followed by reaction at a vacuum degree of -0.082 MPa and 103.5°C for 3.2 hours. The preparation method of titanate coupling agent modified core-shell particles is as follows: corn starch, ethyl acetate, acryloyl chloride and stearyl chloride are weighed in a weight ratio of 76:245:3.2:3.2, pyridine (2.8% of the total weight of the above raw materials) is used as a catalyst, and an esterification reaction is carried out for 1.8 hours to obtain esterified starch (ES); 9 parts by weight of the esterified starch is added into 9 times the weight of water to obtain a gelatinized liquid, the temperature is increased to 83°C, 22.5 parts by weight of ethyl acrylate and 0.2 parts by weight of titanate coupling agent are added, and the mixture is thoroughly stirred, and then 0.8 parts by weight of a 5% potassium persulfate aqueous solution is added, and the mixture is stirred at 250 r / min for 6.7 hours; then the temperature is lowered to 58°C, glycidyl methacrylate (GMA) (0.6% of the total weight of the reactants) is added, the temperature is first increased to 72°C and stirred for 0.7 hours, and then increased to 79.5°C and stirred for 1.5 hours, and the obtained product is subjected to demulsification treatment and dried.

[0032] Step b: 58 parts by mass of polylactic acid (PLA) was used as the plastic phase, 28 parts by mass of bio-based itaconate rubber (Bio-ItBR) and 15 parts by mass of bio-based ethylene-vinyl acetate copolymer (EVA) were used as the rubber phase, maleic anhydride grafted cardanol (2.5 parts by mass of maleic anhydride grafted cardanol was added to every 100 parts by mass of the rubber phase) and ethylene-acrylic acid copolymer (EAA) (1.6 parts by mass of EAA was added to every 100 parts by mass of the rubber phase) were used as composite compatibilizers, 7.2% of the total mass of the plastic phase and the rubber phase was added as a titanate coupling agent-modified core-shell particles as a reinforcing agent, and dicumyl peroxide (DCP initiator) (0.25 parts by mass of DCP initiator was added to every 100 parts by mass of the rubber phase) was used in combination with electron beam radiation initiation to prepare bio-based PLA / Bio-ItBR / EVA by a dynamic vulcanization process. TPV: First, the rubber phase and compatibilizer were placed in an open mill at 35°C, and the reinforcing agent that had been previously irradiated with microwaves (microwave power of 500W, temperature of 88°C, time of 40s) was slowly added and mixed for 4 minutes until no obvious particles were present. Then, 1 / 3 of the total mass of dicumyl peroxide was added and mixed for 1.5 minutes to obtain a blended rubber. The HAAKE torque rheometer was heated to 161.5°C and the speed was adjusted to 90r / min. After the plastic phase was added and melted for 5 minutes, the remaining dicumyl peroxide and the blended rubber were added and dynamically vulcanized for 6.5 minutes. At the same time, electron beam radiation was turned on, the dose rate was controlled at 9 kGy / min, and the total dose was controlled at 18 kGy. The radiation time was synchronized with the dynamic vulcanization time to accelerate the decomposition of DCP to produce free radicals. At the same time, the electron beam triggered the breakage of the rubber molecular chain, realizing the synergistic effect of "thermal initiation + radiation initiation".

[0033] Comparative Example 1: The difference from Example 3 is that dicumyl peroxide is added once after the plastic phase is melted: Bio-based PLA / Bio-ItBR / EVA TPV is prepared by dynamic vulcanization process: first, the rubber phase and the compatibilizer are placed in an open mill at 35°C, and the reinforcing agent that has been microwave-irradiated in advance (microwave power of 500W, temperature of 88°C, time of 40s) is slowly added, and mixed for 4 minutes until there are no obvious particles to obtain a blended rubber; the HAAKE torque rheometer is heated to 161.5°C, the speed is adjusted to 90r / min, and the plastic phase is added and melted for 5 minutes, dicumyl peroxide and the blended rubber are added and dynamically vulcanized for 8 minutes, and electron beam radiation is turned on at the same time, the dose rate is controlled at 9 kGy / min, the total dose is controlled at 18 kGy, and the irradiation time is synchronized with the dynamic vulcanization time.

[0034] Comparative Example 2: The difference from Example 3 is that only dicumyl peroxide initiation is used, and electron beam radiation initiation is not combined: bio-based PLA / Bio-ItBR / EVA TPV is prepared by dynamic vulcanization process: first, the rubber phase and the compatibilizer are placed in an open mill at 35°C, and the reinforcing agent that has been pre-irradiated with microwaves (microwave power of 500W, temperature of 88°C, time of 40s) is slowly added, and mixed for 4 minutes until there are no obvious particles. Then, 1 / 3 of the total mass of dicumyl peroxide is added and mixed for 1.5 minutes to obtain a blended rubber; the HAAKE torque rheometer is heated to 161.5°C, the speed is adjusted to 90r / min, and after adding the plastic phase, it is melted for 5 minutes, and the remaining dicumyl peroxide and the blended rubber are added for dynamic vulcanization for 6.5 minutes.

[0035] Comparative Example 3: The difference from Example 3 is that the reinforcing agent is not subjected to microwave irradiation: a bio-based PLA / Bio-ItBR / EVA TPV is prepared by a dynamic vulcanization process: the rubber phase and the compatibilizer are first placed in an open mill at 35°C, the reinforcing agent is slowly added, and the mixture is mixed for 4 minutes until there are no obvious particles. Then, 1 / 3 of the total mass of dicumyl peroxide is added and mixed for 1.5 minutes to obtain a blended rubber; the HAAKE torque rheometer is heated to 161.5°C, the speed is adjusted to 90 r / min, and the plastic phase is added and melted for 5 minutes. The remaining dicumyl peroxide and the blended rubber are added and dynamically vulcanized for 6.5 minutes. At the same time, electron beam radiation is turned on, the dose rate is controlled at 9 kGy / min, the total dose is controlled at 18 kGy, and the irradiation time is synchronized with the dynamic vulcanization time.

[0036] Comparative Example 4: The difference from Example 3 is that the process parameters of the dynamic vulcanization process are adjusted after the blended rubber is obtained: the bio-based PLA / Bio-ItBR / EVA TPV is prepared by the dynamic vulcanization process: the rubber phase and the compatibilizer are first placed in an open mill at 35°C, and the reinforcing agent that has been previously irradiated with microwaves (microwave power of 500W, temperature of 88°C, time of 40s) is slowly added, and mixed for 4 minutes until there are no obvious particles. Then, 1 / 3 of the total mass of diisopropyl peroxide is added and mixed for 1.5 minutes to obtain a blended rubber; the HAAKE torque rheometer is heated to 167.5°C, the speed is adjusted to 120r / min, and the plastic phase is added and melted for 7 minutes. The remaining diisopropyl peroxide and the blended rubber are added and dynamically vulcanized for 8 minutes. At the same time, the electron beam radiation is turned on, the dose rate is controlled at 5 kGy / min, the total dose is controlled at 25 kGy, and the irradiation time is synchronized with the dynamic vulcanization time.

[0037] Experimental Example: The following performance tests were performed on the bio-based PLA / Bio-ItBR / EVA TPVs prepared in Examples 1 to 3 and Comparative Examples 1 to 4. The results are shown in Table 1.

[0038] Shore hardness: GB / T 531.1-2008;

[0039] Tensile strength: GB / T 1040.2-2022;

[0040] Elongation at break: GB / T 1040.2-2022;

[0041] Compression set: GB / T 7759.1-2015.

[0042] Table 1 Performance test results

[0043]

[0044] From Table 1 we can see that:

[0045] The Shore hardness of Examples 1 to 3 is 62 to 65A, which is higher than that of Comparative Example 1 (60A) and Comparative Example 3 (60A). The hardness distribution of the present invention is concentrated, indicating that the two-batch addition of diisopropylbenzene peroxide and the advance microwave irradiation of the reinforcing agent are beneficial to enhancing the hardness of the material.

[0046] The tensile strengths of Examples 1-3 ranged from 10.5 to 13.3 MPa. The tensile strength of Example 3 (12.8 MPa) was higher than that of Comparative Examples 1 (11.0 MPa), 2 (12.1 MPa), and 4 (10.1 MPa). This indicates that the two-step addition of dicumyl peroxide, the use of dicumyl peroxide combined with electron beam radiation initiation, and the rational configuration of dynamic vulcanization process parameters are beneficial for increasing the crosslink density of the material's molecular chains and enhancing its tensile strength.

[0047] The elongations at break of Examples 1-3 ranged from 459.7% to 488.6%. The elongation at break of Example 3 (472.1%) was higher than that of Comparative Example 1 (438.5%), Comparative Example 2 (461.2%), and Comparative Example 4 (429.1%). This indicates that the two-step addition of dicumyl peroxide, the use of dicumyl peroxide combined with electron beam radiation initiation, and the rational configuration of dynamic vulcanization process parameters ensure that the material possesses excellent flexibility and deformation resistance.

[0048] The compression set (27°C, 24 h) of Examples 1-3 was only 27-29%. The compression set of Example 3 (27%) was lower than that of Comparative Example 1 (31%), Comparative Example 3 (29%), and Comparative Example 4 (33%). This indicates that the two-step addition of dicumyl peroxide, the advance microwave irradiation of the reinforcing agent, and the rational configuration of dynamic vulcanization process parameters are beneficial for improving the material's elastic recovery and reducing irreversible deformation.

[0049] In summary, the present invention achieves the bio-based PLA / Bio-ItBR / EVA TPVs prepared in Examples 1 to 3 of the present invention by adding dicumyl peroxide in two batches, subjecting the reinforcing agent to microwave radiation in advance, using dicumyl peroxide combined with electron beam radiation initiation, and rationally configuring dynamic vulcanization process parameters. The PLA / Bio-ItBR / EVA TPVs have medium hardness, above-medium tensile strength, excellent ductility and high elasticity, good elastic memory and compression deformation resistance, and can be used in the preparation of products such as seals.

[0050] The present invention uses polylactic acid as the plastic phase, bio-based itaconate rubber and bio-based ethylene-vinyl acetate copolymer as the rubber phase, maleic anhydride-grafted cardanol and ethylene-acrylic acid copolymer as a composite compatibilizer, and titanate coupling agent-modified core-shell particles as a reinforcing agent, adding 6-8.8% of the total mass of the plastic and rubber phases. The bio-based PLA / Bio-ItBR / EVA TPV is prepared using a dynamic vulcanization process using dicumyl peroxide combined with electron beam radiation initiation. This improves the compatibility between the plastic and rubber phases, reduces phase separation problems caused by polarity differences, and avoids high-temperature precipitation similar to bio-soybean oil, thereby preventing component contamination and accelerating rubber phase aging. The present invention uses dicumyl peroxide combined with an electron beam radiation-induced dynamic vulcanization process to form a uniform cross-linked network, improving the stability of material properties.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a bio-based TPV composite material, characterized in that: Bio-based PLA / Bio-ItBR / EVA was prepared by dynamic vulcanization process using polylactic acid as plastic phase, bio-based itaconate rubber and bio-based ethylene-vinyl acetate copolymer as rubber phase, maleic anhydride grafted cardanol and ethylene-acrylic acid copolymer as composite compatibilizer, and titanate coupling agent modified core-shell particles as reinforcing agent with a total weight of 6-8.8% of the total weight of the plastic phase and rubber phase. Dicumyl peroxide combined with electron beam radiation initiation was used. TPV: First, place the rubber phase and compatibilizer in an open mill at 30-45°C, slowly add the reinforcing agent that has been microwaved in advance, and mix for 3-5 minutes. Then, add 1 / 2-1 / 3 of the total mass of dicumyl peroxide and mix for 1-2 minutes to obtain a blended rubber. Heat the HAAKE torque rheometer to 160.5-162.8°C and adjust the speed to 80-100 rpm. After adding the plastic phase, melt it for 4.5-6 minutes. Add the remaining dicumyl peroxide and the blended rubber and perform dynamic vulcanization for 6-7.5 minutes. At the same time, start electron beam radiation with a dose rate of 8-10 kGy / min and a total dose of 15-20 kGy. The radiation time is synchronized with the dynamic vulcanization time. The preparation method of the titanate coupling agent modified core-shell particles is as follows: corn starch, ethyl acetate, acryloyl chloride and stearyl chloride are weighed in a weight ratio of 75-78: 243-248: 2.8-3.2: 2.8-3.2, pyridine (2.2-3.3% of the total weight of the above raw materials) is used as a catalyst, and an esterification reaction is carried out for 1.7-2 hours to obtain esterified starch; 8-10 parts by weight of the esterified starch is added into 8-10 times the weight of water to obtain a gelatinized liquid, the temperature is increased to 82-85°C, and 22-23 parts by weight of acryloyl chloride are added. Ethyl acetate and 0.1-0.3 parts by mass of titanate coupling agent are fully stirred, and then 0.7-1 parts by mass of 5% potassium persulfate aqueous solution are added, and the reaction is stirred at 200-300 r / min for 6.5-7 hours; then the temperature is lowered to 55-60°C, and 0.5-0.7% of the total mass of the reactants of glycidyl methacrylate are added, and the temperature is first raised to 70-75°C and stirred for 0.5-1 hour, and then raised to 78-80°C and stirred for 1-1.8 hours. The obtained product is subjected to demulsification treatment and dried.

2. The method for preparing the bio-based TPV composite material according to claim 1, characterized in that: The preparation method of the maleic anhydride-grafted cardanol is as follows: cardanol and maleic anhydride are mixed in a mass ratio of 4 to 5:1, stirred and reacted at 95 to 98° C. for 1.8 to 2 hours, p-toluenesulfonic acid is added in an amount of 5 to 5.8% of the total mass of the raw materials, and then placed in a vacuum degree of -0.08 to -0.085 MPa and 101 to 105° C. for reaction for 3 to 3.5 hours.

3. The method for preparing the bio-based TPV composite material according to claim 1, characterized in that: Microwave radiation parameters: microwave power 400~600W, temperature 85~90℃, time 30~50s.

4. The method for preparing the bio-based TPV composite material according to claim 1, characterized in that: 0.2 to 0.3 parts by mass of dicumyl peroxide is added to every 100 parts by mass of the rubber phase.

5. The method for preparing the bio-based TPV composite material according to claim 1, characterized in that: 2 to 3 parts by mass of maleic anhydride-grafted cardanol are added to every 100 parts by mass of the rubber phase.

6. The method for preparing the bio-based TPV composite material according to claim 1, characterized in that: 1 to 2 parts by mass of ethylene-acrylic acid copolymer is added to every 100 parts by mass of the rubber phase.

7. The method for preparing a bio-based TPV composite material according to any one of claims 1 to 6, characterized in that: The mass ratio of rubber phase to plastic phase is 40~45:55~60.

8. A bio-based TPV composite material prepared according to the preparation method according to any one of claims 1 to 6.

9. The bio-based TPV composite material according to claim 8, characterized in that The bio-based TPV composite material has a Shore hardness of 62-65 A, a tensile strength of 10.5-13.3 MPa, an elongation at break of 459.7-488.6%, and a compression set of 27-29%.

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