Bio-based TPV composite material and preparation method thereof

Abstract

The invention discloses a bio-based TPV composite material and a preparation method thereof, and belongs to the technical field of preparation of TPV composite materials, polylactic acid is used as a plastic phase, bio-based itaconate rubber and a bio-based ethylene-vinyl acetate copolymer are used as a rubber phase, maleic anhydride grafted cardanol and an ethylene-acrylic acid copolymer are used as a composite compatibilizer, and the bio-based TPV composite material is prepared. Titanate coupling agent modified core-shell particles are added to serve as a reinforcing agent, dicumyl peroxide is combined with an electron beam radiation initiation mode, and the bio-based PLA / Bio-ItBR / EVA TPV is prepared through a dynamic vulcanization process. The product has medium hardness, medium tensile strength, excellent ductility and high elasticity, and good elastic memory ability and compressive deformation resistance. The compatibility between a plastic phase and a rubber phase is improved, and the phase separation problem caused by polarity difference is reduced. The dicumyl peroxide is combined with a dynamic vulcanization process initiated by electron beam radiation, so that a uniform cross-linked network can be formed, and the stability of the material performance is improved.

Description

Technical Field

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

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

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

[0004] For example, CN118063972A discloses a bio-based TPV composite material for vehicles and a preparation method thereof, including the following raw materials in parts by mass: 10 - 35 parts of bio-based PP, 25 - 50 parts of bio-based EPDM, 35 - 50 parts of bio-soybean oil, 1 - 10 parts of biomass filler (white carbon black), 1 - 5 parts of color masterbatch, 1 - 10 parts of composite vulcanizing agent, 1 - 5 parts of composite stabilizer, and 1 - 10 parts of lubricant. First, bio-based PP, bio-based EPDM, biomass filler, color masterbatch particles, and bio-soybean oil are fully plasticized in a screw, and then combined with additives such as composite vulcanizing agent and composite stabilizer, and extruded and granulated. A vulcanization system composed of tert-butyl peroxyacetate and di-tert-butyl peroxide is used. First, the vulcanization reaction is carried out step by step by tert-butyl peroxyacetate, and then di-tert-butyl peroxide crosslinks the remaining incompletely vulcanized parts through its own molecular chain, promoting the uniform dispersion of each component inside the material, improving the crosslinking density, and further improving the elastic properties of the bio-based TPV material.

[0005] However, it has the following defects: (1) First, the amount of bio-soybean oil used is high, and its polarity difference from non-polar bio-based PP / EPDM is large. When used at high temperature for a long time, oil bleeding is likely to occur, polluting components and accelerating the aging of the rubber phase.

[0006] (2) Second, the surface of the biomass filler (white carbon black) is rich in silanol groups, which are prone to form aggregates. In the process of first plasticizing and then adding additives, it is difficult for white carbon black to be uniformly dispersed in the high-viscosity melt, resulting in unstable mechanical properties of the bio-based TPV material.

[0007] 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

[0008] In view of the above-mentioned disadvantages of the prior art, the present invention provides a bio-based TPV composite material and a preparation method thereof.

[0009] To achieve the above object, the present invention is realized through the following technical solutions: A preparation method of a bio-based TPV composite material, using polylactic acid as the plastic phase, bio-based itaconic acid ester rubber and bio-based ethylene-vinyl acetate copolymer as the rubber phase, maleic anhydride grafted cardanol and ethylene-acrylic acid copolymer as the composite compatibilizer, adding 6-8.8% of the total mass of the plastic phase and the rubber phase of titanate coupling agent modified core-shell particles as the reinforcing agent, and using dicumyl peroxide combined with electron beam radiation initiation method to prepare bio-based PLA / Bio-ItBR / EVA TPV by dynamic vulcanization process: first, put the rubber phase and the compatibilizer into an open mill at 30-45 °C, slowly add the reinforcing agent that has been pre-irradiated by microwave, mix and knead for 3-5 min until there are no obvious particles, then add 1 / 2-1 / 3 of the total mass of dicumyl peroxide and mix and knead for 1-2 min to obtain a blend; heat the HAAKE torque rheometer to 160.5-162.8 °C, adjust the rotation speed to 80-100 r / min, add the plastic phase and melt for 4.5-6 min, add the remaining dicumyl peroxide and the blend for dynamic vulcanization for 6-7.5 min, and at the same time turn on the electron beam radiation, control the dose rate at 8-10 kGy / min, and control the total dose at 15-20 kGy, and the radiation time is synchronized with the dynamic vulcanization time.

[0010] Furthermore, the preparation method of the maleic anhydride grafted cardanol is: mix cardanol and maleic anhydride according to a mass ratio of 4-5:1, stir and react at 95-98 °C for 1.8-2 h, add 5-5.8% of the total mass of the raw materials of p-toluenesulfonic acid, and then react at a vacuum degree of -0.08 to -0.085 MPa and 101-105 °C for 3-3.5 h.

[0011] Further, the preparation method of the titanate coupling agent-modified core-shell particles is as follows: Weigh corn starch, ethyl acetate, acryloyl chloride, and stearoyl chloride according to a weight ratio of 75-78:243-248:2.8-3.2:2.8-3.2. Using pyridine at 2.2-3.3% of the total mass of the above raw materials as a catalyst, carry out an esterification reaction for 1.7-2 h to obtain esterified starch. Put 8-10 parts by mass of the esterified starch into 8-10 times the mass of water to obtain a gelatinized solution. Raise the temperature to 82-85 °C, add 22-23 parts by mass of ethyl acrylate and 0.1-0.3 parts by mass of a titanate coupling agent, stir well, then add 0.7-1 part by mass of a 5% aqueous potassium persulfate solution, and stir and react at 200-300 r / min for 6.5-7 h. Then cool down to 55-60 °C, add glycidyl methacrylate at 0.5-0.7% of the total mass of the reactants, first raise the temperature to 70-75 °C and stir and react for 0.5-1 h, then raise the temperature to 78-80 °C and stir and react for 1-1.8 h. The obtained product is subjected to demulsification treatment and drying.

[0012] Further, the microwave radiation parameters are as follows: the microwave power is 400-600 W, the temperature is 85-90 °C, and the time is 30-50 s.

[0013] Further, 0.2-0.3 parts by mass of dicumyl peroxide are added to every 100 parts by mass of the rubber phase.

[0014] Further, 2-3 parts by mass of maleic anhydride-grafted cashew phenol are added to every 100 parts by mass of the rubber phase.

[0015] Further, 1-2 parts by mass of ethylene-acrylic acid copolymer are added to every 100 parts by mass of the rubber phase.

[0016] Further, the mass ratio of the rubber phase to the plastic phase is 40-45:55-60.

[0017] 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 preparation method.

[0018] Further, the Shore hardness of the bio-based TPV composite material is 62-65 A, the tensile strength is 10.5-13.3 MPa, the elongation at break is 459.7-488.6%, and the compression set is 27-29%.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The bio-based PLA / Bio-ItBR / EVA TPV prepared by the present invention has medium hardness, medium to upper tensile strength, excellent ductility and high elasticity, good elastic memory ability and compression set resistance, and can be used for the preparation of products such as seals.

[0020] In the present invention, polylactic acid is used as the plastic phase, bio-based itaconic acid ester rubber and bio-based ethylene-vinyl acetate copolymer are used as the rubber phase, maleic anhydride grafted cardanol and ethylene-acrylic acid copolymer are used as the composite compatibilizer, and titanate coupling agent modified core-shell particles accounting for 6-8.8% of the total mass of the plastic phase and the rubber phase are added as a reinforcing agent. The bio-based PLA / Bio-ItBR / EVA TPV is prepared by using dicumyl peroxide combined with electron beam radiation initiation and adopting a dynamic vulcanization process. The compatibility between the plastic phase and the rubber phase is improved, the phase separation problem caused by the polarity difference is reduced, and the situation similar to the high-temperature precipitation of bio-soybean oil is avoided, so that the components are not polluted and the aging of the rubber phase is not accelerated. The dynamic vulcanization process of the present invention using dicumyl peroxide combined with electron beam radiation initiation can form a uniform crosslinked network and improve the stability of the material properties. Specific Embodiments

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] Example 1: A preparation method of a bio-based TPV composite material, the steps are as follows: Step a: Prepare maleic anhydride grafted cardanol: Mix cardanol and maleic anhydride in a mass ratio of 4:1, stir and react at 98 °C for 1.8 h, add p-toluenesulfonic acid accounting for 5.8% of the total mass of the raw materials, and then react at a vacuum degree of -0.08 MPa and 105 °C for 3 h. The preparation method of the titanate coupling agent modified core-shell particles is: Weigh corn starch, ethyl acetate, acryloyl chloride, and stearoyl chloride according to a weight ratio of 75:248:2.8:2.8, use pyridine accounting for 2.2% of the total mass of the above raw materials as a catalyst, and carry out an esterification reaction for 2 h to obtain esterified starch (ES); Put 8 parts by mass of the esterified starch into 10 times the mass of water to obtain a gelatinized solution, raise the temperature to 82 °C, add 23 parts by mass of ethyl acrylate and 0.1 part by mass of the titanate coupling agent, stir evenly, then add 1 part by mass of a 5% aqueous potassium persulfate solution, and stir and react at 200 r / min for 7 h; Then cool down to 55 °C, add glycidyl methacrylate (GMA) accounting for 0.7% of the total mass of the reactants, first raise the temperature to 70 °C and stir and react for 1 h, then raise the temperature to 78 °C and stir and react for 1.8 h, and carry out demulsification treatment and drying on the obtained product.

[0023] Step b: Using 55 parts by mass of polylactic acid (PLA) as the plastic phase, 30 parts by mass of bio-based itaconic acid ester rubber (Bio-ItBR) and 10 parts by mass of bio-based ethylene-vinyl acetate copolymer (EVA) as the rubber phase, maleic anhydride grafted cashew phenol (adding 3 parts by mass of maleic anhydride grafted cashew phenol per 100 parts by mass of the rubber phase) and ethylene-acrylic acid copolymer (EAA) (adding 1 part by mass of EAA per 100 parts by mass of the rubber phase) as the composite compatibilizer, adding titanate coupling agent modified core-shell particles accounting for 8.8% of the total mass of the plastic phase and the rubber phase as the reinforcing agent, and using dicumyl peroxide (DCP initiator) (adding 0.2 parts by mass of the DCP initiator per 100 parts by mass of the rubber phase) combined with electron beam radiation initiation method to prepare bio-based PLA / Bio-ItBR / EVA TPV by dynamic vulcanization process: First, put the rubber phase and the compatibilizer into an open mill at 45°C, slowly add the reinforcing agent that has been pre-irradiated by microwave (microwave power is 400 W, temperature is 90°C, time is 30 s), mix for 5 min until there are no obvious particles, then add half of the total mass of dicumyl peroxide and mix for 2 min to obtain a blend; Heat the HAAKE torque rheometer to 160.5°C, adjust the rotation speed to 100 r / min, add the plastic phase and melt for 4.5 min, then add the remaining dicumyl peroxide and the blend for dynamic vulcanization for 7.5 min, and at the same time turn on the electron beam radiation, control the dose rate at 8 kGy / min, control the total dose at 20 kGy, and make the radiation time synchronous with the dynamic vulcanization time to accelerate the decomposition of DCP to generate free radicals, and at the same time the electron beam initiates the rupture of rubber molecular chains to achieve the synergistic effect of "thermal initiation + radiation initiation".

[0024] Example 2: A preparation method of a bio-based TPV composite material, the steps are as follows: Step a: Preparation of maleic anhydride grafted cardanol: Mix cardanol and maleic anhydride in a mass ratio of 5:1, stir and react at 95 °C for 2 h. After adding p-toluenesulfonic acid accounting for 5% of the total mass of the raw materials, react at a vacuum degree of -0.085 MPa and 101 °C for 3.5 h. The preparation method of the titanate coupling agent modified core-shell particles is as follows: Weigh corn starch, ethyl acetate, acryloyl chloride and stearoyl chloride according to a weight ratio of 78:243:3.2:2.8. Using pyridine accounting for 3.3% of the total mass of the above raw materials as a catalyst, carry out an esterification reaction for 1.7 h to obtain esterified starch (ES); Take 10 parts by mass of the esterified starch and put it into 8 times the mass of water to obtain a gelatinized solution. Raise the temperature to 85 °C, add 22 parts by mass of ethyl acrylate and 0.3 parts by mass of the titanate coupling agent, stir evenly, then add 0.7 parts by mass of a 5% potassium persulfate aqueous solution, and stir and react at 300 r / min for 6.5 h; Then cool down to 60 °C, add glycidyl methacrylate (GMA) accounting for 0.5% of the total mass of the reactants, first raise the temperature to 75 °C and stir and react for 0.5 h, then raise the temperature to 80 °C and stir and react for 1 h. The obtained product is subjected to demulsification treatment and drying.

[0025] Step b: Using 60 parts by mass of polylactic acid (PLA) as the plastic phase, 25 parts by mass of bio-based itaconic acid ester rubber (Bio-ItBR) and 20 parts by mass of bio-based ethylene-vinyl acetate copolymer (EVA) as the rubber phase, using maleic anhydride grafted cardanol (add 2 parts by mass of maleic anhydride grafted cardanol per 100 parts by mass of the rubber phase) and ethylene-acrylic acid copolymer (EAA) (add 2 parts by mass of EAA per 100 parts by mass of the rubber phase) as the composite compatibilizer, adding titanate coupling agent modified core-shell particles accounting for 6% of the total mass of the plastic phase and the rubber phase as the reinforcing agent, using dicumyl peroxide (DCP initiator) (add 0.3 parts by mass of the DCP initiator per 100 parts by mass of the rubber phase) combined with electron beam radiation initiation method, and using a dynamic vulcanization process to prepare bio-based PLA / Bio-ItBR / EVA TPV: First, put the rubber phase and the compatibilizer into an open mill at 30 °C, slowly add the reinforcing agent that has been pre-irradiated by microwave (microwave power is 600 W, temperature is 85 °C, time is 50 s), and mix for 3 min until there are no obvious particles, then add 1 / 3 of the total mass of dicumyl peroxide and mix for 1 min to obtain a blend; Heat the HAAKE torque rheometer to 162.8 °C, adjust the rotation speed to 80 r / min, add the plastic phase and melt for 6 min, add the remaining dicumyl peroxide and the blend for dynamic vulcanization for 6 min, and at the same time turn on the electron beam radiation, control the dose rate at 10 kGy / min, control the total dose at 15 kGy, and the radiation time is synchronized with the dynamic vulcanization time to accelerate the decomposition of DCP to generate free radicals, and at the same time the electron beam initiates the rupture of the rubber molecular chain to achieve the synergistic effect of "thermal initiation + radiation initiation".

[0026] Example 3: A preparation method of a bio-based TPV composite material, the steps are as follows: Step a: Prepare maleic anhydride-grafted cardanol: Mix cardanol and maleic anhydride according to a mass ratio of 4.5:1, stir and react at 96 °C for 1.9 h. After adding p-toluenesulfonic acid accounting for 5.5% of the total mass of the raw materials, place it under a vacuum of -0.082 MPa and react at 103.5 °C for 3.2 h. The preparation method of the titanate coupling agent-modified core-shell particles is as follows: Weigh corn starch, ethyl acetate, acryloyl chloride, and stearoyl chloride according to a weight ratio of 76:245:3.2:3.2. Using pyridine accounting for 2.8% of the total mass of the above raw materials as a catalyst, carry out an esterification reaction for 1.8 h to obtain esterified starch (ES); put 9 parts by mass of the esterified starch into 9 times the mass of water to obtain a gelatinized solution, raise the temperature to 83 °C, add 22.5 parts by mass of ethyl acrylate and 0.2 part by mass of titanate coupling agent, stir evenly, then add 0.8 part by mass of a 5% aqueous solution of potassium persulfate, and stir and react at 250 r / min for 6.7 h; then cool down to 58 °C, add glycidyl methacrylate (GMA) accounting for 0.6% of the total mass of the reactants, first raise the temperature to 72 °C and stir and react for 0.7 h, then raise the temperature to 79.5 °C and stir and react for 1.5 h. The obtained product is subjected to demulsification treatment and drying.

[0027] Step b: Using 58 parts by mass of polylactic acid (PLA) as the plastic phase, 28 parts by mass of bio-based itaconic acid ester rubber (Bio-ItBR) and 15 parts by mass of bio-based ethylene-vinyl acetate copolymer (EVA) as the rubber phase, maleic anhydride grafted cardanol (2.5 parts by mass of maleic anhydride grafted cardanol is added to every 100 parts by mass of the rubber phase) and ethylene-acrylic acid copolymer (EAA) (1.6 parts by mass of EAA is added to every 100 parts by mass of the rubber phase) as the composite compatibilizer, adding titanate coupling agent modified core-shell particles accounting for 7.2% of the total mass of the plastic phase and the rubber phase as the reinforcing agent, and using dicumyl peroxide (DCP initiator) (0.25 parts by mass of DCP initiator is added to every 100 parts by mass of the rubber phase) combined with electron beam radiation initiation method, and preparing bio-based PLA / Bio-ItBR / EVA TPV by dynamic vulcanization process: First, put the rubber phase and the compatibilizer into an open mill at 35°C, slowly add the reinforcing agent that has been pre-microwave irradiated (microwave power is 500 W, temperature is 88°C, time is 40 s), mix for 4 min until there are no obvious particles, then add 1 / 3 of the total mass of dicumyl peroxide and mix for 1.5 min to obtain a blend; Heat the HAAKE torque rheometer to 161.5°C, adjust the rotation speed to 90 r / min, add the plastic phase and melt for 5 min, add the remaining dicumyl peroxide and the blend for dynamic vulcanization for 6.5 min, and at the same time turn on the electron beam radiation, control the dose rate at 9 kGy / min, control the total dose at 18 kGy, and make the radiation time synchronous with the dynamic vulcanization time to accelerate the decomposition of DCP to generate free radicals, and at the same time the electron beam initiates the rupture of the rubber molecular chain to achieve the synergistic effect of "thermal initiation + radiation initiation".

[0028] Comparative Example 1: The difference from Example 3 is that the addition of dicumyl peroxide is carried out in one step after the plastic phase is melted: Prepare bio-based PLA / Bio-ItBR / EVA TPV by dynamic vulcanization process: First, put the rubber phase and the compatibilizer into an open mill at 35°C, slowly add the reinforcing agent that has been pre-microwave irradiated (microwave power is 500 W, temperature is 88°C, time is 40 s), mix for 4 min until there are no obvious particles to obtain a blend; Heat the HAAKE torque rheometer to 161.5°C, adjust the rotation speed to 90 r / min, add the plastic phase and melt for 5 min, add dicumyl peroxide and the blend for dynamic vulcanization for 8 min, and at the same time turn on the electron beam radiation, control the dose rate at 9 kGy / min, control the total dose at 18 kGy, and make the radiation time synchronous with the dynamic vulcanization time.

[0029] Comparative Example 2: Different from Example 3, only the dicumyl peroxide initiation method is used without combining the electron beam radiation initiation method: A bio-based PLA / Bio-ItBR / EVA TPV is prepared by a dynamic vulcanization process. First, the rubber phase and the compatibilizer are put into an open mill at 35°C, and the reinforcing agent that has been pre-radiated by microwave (microwave power is 500 W, temperature is 88°C, time is 40 s) is slowly added, and mixed for 4 min until there are no obvious particles. Then, an amount equal to 1 / 3 of the total mass of dicumyl peroxide is added and mixed for 1.5 min to obtain a blend rubber. The HAAKE torque rheometer is heated to 161.5°C, the rotation speed is adjusted to 90 r / min, the plastic phase is added and melted for 5 min, and the remaining dicumyl peroxide and the blend rubber are added for dynamic vulcanization for 6.5 min.

[0030] Comparative Example 3: Different from Example 3, the reinforcing agent is not subjected to microwave radiation: A bio-based PLA / Bio-ItBR / EVA TPV is prepared by a dynamic vulcanization process. First, the rubber phase and the compatibilizer are put into an open mill at 35°C, the reinforcing agent is slowly added, and mixed for 4 min until there are no obvious particles. Then, an amount equal to 1 / 3 of the total mass of dicumyl peroxide is added and mixed for 1.5 min to obtain a blend rubber. The HAAKE torque rheometer is heated to 161.5°C, the rotation speed is adjusted to 90 r / min, the plastic phase is added and melted for 5 min, and the remaining dicumyl peroxide and the blend rubber are added for dynamic vulcanization for 6.5 min. 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 radiation time is synchronized with the dynamic vulcanization time.

[0031] Comparative Example 4: Different from Example 3, the process parameters after obtaining the blend rubber are adjusted in the dynamic vulcanization process: A bio-based PLA / Bio-ItBR / EVA TPV is prepared by a dynamic vulcanization process. First, the rubber phase and the compatibilizer are put into an open mill at 35°C, and the reinforcing agent that has been pre-radiated by microwave (microwave power is 500 W, temperature is 88°C, time is 40 s) is slowly added, and mixed for 4 min until there are no obvious particles. Then, an amount equal to 1 / 3 of the total mass of dicumyl peroxide is added and mixed for 1.5 min to obtain a blend rubber. The HAAKE torque rheometer is heated to 167.5°C, the rotation speed is adjusted to 120 r / min, the plastic phase is added and melted for 7 min, and the remaining dicumyl peroxide and the blend rubber are added for dynamic vulcanization for 8 min. At the same time, 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 radiation time is synchronized with the dynamic vulcanization time.

[0032] Experimental Example: The following performance tests are carried out 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.

[0033] Shore hardness: GB / T 531.1-2008; Tensile strength: GB / T 1040.2-2022; Elongation at break: GB / T 1040.2-2022; Compression set: GB / T 7759.1-2015.

[0034] Table 1 Performance test results

[0035] It can be seen from Table 1 that: The Shore hardness of Examples 1-3 is 62-65A, 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 method of dicumyl peroxide and the prior microwave radiation of the reinforcing agent are beneficial to enhancing the hardness of the material.

[0036] The tensile strength of Examples 1-3 is 10.5-13.3 MPa. The tensile strength of Example 3 (12.8 MPa) is higher than that of Comparative Example 1 (11.0 MPa), Comparative Example 2 (12.1 MPa) and Comparative Example 4 (10.1 MPa). It shows that the two-batch addition method of dicumyl peroxide, the method of combining dicumyl peroxide with electron beam radiation initiation, and the reasonable configuration of dynamic vulcanization process parameters are beneficial to improving the crosslinking density of the molecular chain of the material and enhancing the tensile strength of the material.

[0037] The elongation at break of Examples 1-3 is 459.7-488.6%. The elongation at break of Example 3 (472.1%) is higher than that of Comparative Example 1 (438.5%), Comparative Example 2 (461.2%) and Comparative Example 4 (429.1%). It shows that the two-batch addition method of dicumyl peroxide, the method of combining dicumyl peroxide with electron beam radiation initiation, and the reasonable configuration of dynamic vulcanization process parameters can ensure that the material has good flexibility and anti-deformation ability.

[0038] The compression set of Examples 1-3 (27 °C, 24 h) is only 27-29%. The compression set of Example 3 (27%) is lower than that of Comparative Example 1 (31%), Comparative Example 3 (29%) and Comparative Example 4 (33%), indicating that the two-batch addition method of dicumyl peroxide, the prior microwave radiation of the reinforcing agent, and the reasonable configuration of dynamic vulcanization process parameters are beneficial to improving the elastic recovery performance of the material and reducing irreversible deformation.

[0039] In summary, through the two-batch addition method of dicumyl peroxide, the early microwave radiation of the reinforcing agent, the use of the combination of dicumyl peroxide and electron beam radiation initiation method, and the reasonable configuration of the dynamic vulcanization process parameters, the bio-based PLA / Bio-ItBR / EVA TPV prepared in Examples 1 to 3 of the present invention has medium hardness, medium to high tensile strength, excellent ductility and high elasticity, good elastic memory ability and compression set resistance, and can be used for the preparation of products such as seals.

[0040] The present invention uses polylactic acid as the plastic phase, bio-based itaconic acid ester rubber and bio-based ethylene-vinyl acetate copolymer as the rubber phase, maleic anhydride grafted cashew phenol and ethylene-acrylic acid copolymer as the composite compatibilizer, adds titanate coupling agent modified core-shell particles accounting for 6-8.8% of the total mass of the plastic phase and the rubber phase as the reinforcing agent, and uses the combination of dicumyl peroxide and electron beam radiation initiation method to prepare bio-based PLA / Bio-ItBR / EVA TPV by means of dynamic vulcanization process. It improves the compatibility between the plastic phase and the rubber phase, reduces the phase separation problem caused by polarity difference, and avoids the situation similar to the high-temperature precipitation of bio-soybean oil, thus not polluting the components and accelerating the aging of the rubber phase. The dynamic vulcanization process of the present invention using the combination of dicumyl peroxide and electron beam radiation initiation can form a uniform crosslinking network and improve the stability of material properties.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a bio-based TPV composite material, characterized in that, Using polylactic acid as the plastic phase, bio-based itaconic acid ester rubber and bio-based ethylene-vinyl acetate copolymer as the rubber phase, maleic anhydride grafted cardanol and ethylene-acrylic acid copolymer as the composite compatibilizer, adding 6-8.8% of the total mass of the plastic phase and the rubber phase of titanate coupling agent modified core-shell particles as the reinforcing agent, and using dicumyl peroxide combined with electron beam radiation initiation method, a bio-based PLA / Bio-ItBR / EVA TPV is prepared by a dynamic vulcanization process: first, put the rubber phase and the compatibilizer into an open mill at 30-45 °C, slowly add the reinforcing agent that has been irradiated by microwave in advance, mix for 3-5 min, then add 1 / 2-1 / 3 of the total mass of dicumyl peroxide and mix for 1-2 min to obtain a blend; heat the HAAKE torque rheometer to 160.5-162.8 °C, adjust the rotation speed to 80-100 r / min, add the plastic phase and melt for 4.5-6 min, add the remaining dicumyl peroxide and the blend for dynamic vulcanization for 6-7.5 min, and at the same time turn on the electron beam radiation, control the dose rate at 8-10 kGy / min, and control the total dose at 15-20 kGy, and the radiation time is synchronized with the dynamic vulcanization time.

2. The preparation method of 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: mix cardanol and maleic anhydride according to a mass ratio of 4-5:1, stir and react at 95-98 °C for 1.8-2 h, add 5-5.8% of the total mass of the raw materials of p-toluenesulfonic acid, and then react at a vacuum degree of -0.08~-0.085 MPa and 101-105 °C for 3-3.5 h.

3. The preparation method of the bio-based TPV composite material according to claim 2, wherein The preparation method of the titanate coupling agent modified core-shell particles is as follows: weigh corn starch, ethyl acetate, acryloyl chloride and stearoyl chloride according to a weight ratio of 75-78:243-248:2.8-3.2:2.8-3.2, use 2.2-3.3% of the total mass of the above raw materials of pyridine as the catalyst, and carry out an esterification reaction for 1.7-2 h to obtain esterified starch; take 8-10 parts by mass of the esterified starch and put it into 8-10 times the mass of water to obtain a gelatinized solution, raise the temperature to 82-85 °C, add 22-23 parts by mass of ethyl acrylate and 0.1-0.3 parts by mass of the titanate coupling agent, stir evenly, then add 0.7-1 part by mass of 5% potassium persulfate aqueous solution, and stir and react at 200-300 r / min for 6.5-7 h; then cool down to 55-60 °C, add 0.5-0.7% of the total mass of the reactants of glycidyl methacrylate, first raise the temperature to 70-75 °C and stir and react for 0.5-1 h, then raise the temperature to 78-80 °C and stir and react for 1-1.8 h, and carry out demulsification treatment and drying on the obtained product.

4. The preparation method of the bio-based TPV composite material according to claim 1, wherein Microwave radiation parameters: the microwave power is 400-600 W, the temperature is 85-90 °C, and the time is 30-50 s.

5. The preparation method of the bio-based TPV composite material according to claim 1, characterized in that, Add 0.2-0.3 parts by mass of dicumyl peroxide to every 100 parts by mass of the rubber phase.

6. The preparation method of the bio-based TPV composite material according to claim 1, wherein, Add 2-3 parts by mass of maleic anhydride grafted cardanol to every 100 parts by mass of the rubber phase.

7. The preparation method of the bio-based TPV composite material according to claim 1, wherein Add 1-2 parts by mass of ethylene-acrylic acid copolymer to every 100 parts by mass of the rubber phase.

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

9. A bio-based TPV composite material prepared by the preparation method according to any one of claims 1 - 7.

10. The bio-based TPV composite material according to claim 9, wherein The Shore hardness of the bio-based TPV composite material is 62 - 65 A, the tensile strength is 10.5 - 13.3 MPa, the elongation at break is 459.7 - 488.6%, and the compression set is 27 - 29%.

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