High-strength and high-toughness ABS material and preparation method thereof

Abstract

The invention relates to a high-strength and high-toughness ABS material and a preparation method thereof. The composition is composed of 100 parts by weight of ABS resin, 15 to 25 parts by weight of surface modified needle-like wollastonite, 8 to 12 parts by weight of an ethylene acrylate copolymer containing a maleic anhydride group, and 0.5 to 2 parts by weight of epoxidized soybean oil. The wollastonite and the copolymer are pre-activated through a dry method to form an interface chemical bonding structure, and the epoxidized soybean oil is injected in a side feeding mode to achieve interface selective distribution. Through a space cooperation mechanism of rigid particles and flexible chain segments, the tensile strength is improved to 62 MPa or above, meanwhile, the impact strength reaches 35 kJ / m < 2 > or above, and the problem that strength and toughness are difficult to achieve at the same time in a traditional modification technology is solved. The preparation method adopts conventional twin-screw extrusion equipment, does not need solvent recovery, and is suitable for industrial production. The composition is suitable for application scenes requiring high strength and high toughness, such as automotive upholstery and electronic and electric appliance shells.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a resin composition based on acrylonitrile butadiene styrene copolymer and its preparation method, particularly an ABS resin composition that combines high strength and high toughness. This composition is suitable for automotive interior structural parts and electronic and electrical housing products with stringent mechanical performance requirements. Background Technology

[0002] Acrylonitrile butadiene styrene copolymer, commonly known as ABS resin, is an engineering plastic with excellent comprehensive properties, widely used in the automotive, electronics, and home appliance industries. Ordinary ABS resin has a tensile strength of approximately 45 MPa and an impact strength of approximately 18 kJ per square meter. With increasingly stringent lightweight and safety regulations, automotive parts and electronic housings are placing higher demands on the mechanical properties of materials, requiring improvements in strength and toughness while maintaining processability.

[0003] In existing technologies, adding inorganic rigid fillers to ABS resin can improve strength, but it leads to a significant decrease in toughness. For example, adding 20 wt% ordinary wollastonite can increase tensile strength to 58 MPa, but impact strength will drop to below 10 kJ / m², a decrease of more than 40%. Conversely, adding elastomer toughening agents can improve impact strength, but it reduces tensile strength to below 50 MPa. This inverse relationship between strength and toughness has become a technical bottleneck in ABS modification.

[0004] Some existing technologies attempt to use inorganic fillers and toughening agents simultaneously, but simple physical blending is insufficient to achieve a synergistic effect. Poor interfacial compatibility leads to stress concentration, making the product prone to cracking at the filler-matrix interface under stress. Although silane coupling agent modification can improve the dispersibility of inorganic fillers, it cannot resolve the functional conflict between rigid particles and flexible toughening agents in the interfacial region.

[0005] Therefore, developing an ABS resin composition that simultaneously improves strength and toughness through synergistic effects between components has significant industrial application value. Summary of the Invention

[0006] The technical concept of this invention lies in constructing a multi-scale interface synergistic enhancement system. This system consists of three levels of structural units working synergistically to form a unique force transmission network. The three-level interface synergistic structure of this invention is achieved through precise molecular-level formulation design. The chemical structure parameters and dosage ranges of each component are determined through orthogonal optimization; deviations from these ranges will lead to interface effect mismatch.

[0007] The first layer consists of alpha-wollastonite surface-modified with gamma-aminopropyltriethoxysilane, with the chemical formula CaSiO3 and a molecular weight of 116.16, and its dosage is set at 18 to 22 parts by weight. This dosage is determined based on the nonlinear balance between load transfer efficiency and melt flowability. When the dosage is less than 18 parts, the rigid framework density per unit volume is less than 1.2 × 10⁻⁶. 6 With each particle per cubic millimeter, the tensile strength increase is less than 12%, which is insufficient to meet high-strength requirements. When the dosage exceeds 22 parts, the total area of ​​the interface region exceeds the coverage limit of epoxidized soybean oil, resulting in an interface defect density of over 15 per square millimeter and a toughness decrease of over 25%. 90 The particle size is 8 to 15 micrometers, ensuring that particles form an effective stress transfer path when oriented in the melt. The second layer is an ethylene-butyl acrylate-maleic anhydride terpolymer, which is randomly copolymerized from ethylene segments, butyl acrylate segments, and maleic anhydride segments, with molar fractions of x, y, and z for each segment, and a number-average molecular weight M. n The molecular weight distribution index (PDI) ranges from 25,000 to 35,000, and from 1.8 to 2.3.

[0008] The copolymer is used in quantities of 9 to 11 parts by weight. The maleic anhydride grafting rate is 3.0 to 3.5 wt%, corresponding to 0.65 to 0.75 mmol anhydride groups per gram of copolymer. When the amount is less than 9 parts, the grafting rate on the wollastonite surface is less than 22%, the interfacial chemical bond spacing is greater than 50 nm, and debonding easily occurs under stress. When the amount exceeds 11 parts, the excessive flexible segments reduce the material's rigidity, with a flexural modulus loss exceeding 18%. The butyl acrylate segment content is 18 to 22 wt%, a proportion that ensures the copolymer's glass transition temperature To. g It has a temperature range of -25 to -30 degrees Celsius and maintains sufficient chain segment mobility at room temperature to dissipate impact energy.

[0009] The third layer is epoxidized soybean oil, chemically known as epoxidized triglyceride, with an epoxy value controlled between 6.0 and 6.5 and an acid value below 0.5 mg KOH per gram. This component is used in quantities of 0.8 to 1.5 parts by weight. When the amount is less than 0.8 parts, the interfacial coverage is less than 65%, and the stress concentration mitigation effect is weak. When the amount exceeds 1.5 parts, the volume fraction of free small molecules not involved in interfacial construction exceeds 0.8%, which may migrate to the product surface, leading to a decrease in surface energy and affecting coating adhesion and durability. The epoxy equivalent is 180 to 190 g / mol; this parameter ensures that it has moderate reactivity with maleic anhydride groups at melt processing temperatures, but without excessive cross-linking.

[0010] The construction of the aforementioned three-tiered structure also relies on an auxiliary stabilizing system. The antioxidant is pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, used in an amount of 0.3 to 0.5 parts by weight. Its melting point is 110 to 125 degrees Celsius, and it stably releases free radical scavenging capabilities at processing temperatures. The lubricant is ethylene bis-stearamide, used in an amount of 0.2 to 0.4 parts by weight. Its long carbon chain structure can form a secondary adsorption layer on the wollastonite surface, assisting in ESO distribution. The total amount of this auxiliary system does not exceed 1 part by weight to avoid excessive enrichment of small molecules interfering with the main interface structure.

[0011] The construction of the aforementioned three-tiered structure also relies on an auxiliary stabilizing system. Ethylene bis-stearamide is used as the lubricant, at a dosage of 0.2 to 0.4 parts by weight. The total amount of this auxiliary system does not exceed 1 part by weight to avoid excessive accumulation of small molecules interfering with the main interface structure.

[0012] The synergistic effect of component proportions was verified through interfacial stoichiometric equilibrium. When the amount of wollastonite was 20 parts, its surface hydroxyl content was approximately 0.8 mmol / g, and the total amount of hydroxyl groups was 16 mmol. When the amount of copolymer was 10 parts, it provided approximately 7 mmol of anhydride groups. Assuming a reaction conversion rate of 70%, the actual consumption of hydroxyl groups was 4.9 mmol. The remaining hydroxyl groups reacted with the epoxy groups of ESO. When the amount of ESO was 1.2 parts, it provided approximately 3.5 mmol of epoxy groups, which precisely achieved an interfacial chemical bonding saturation greater than 85%. This stoichiometric relationship ensured that there were no excess unreacted functional groups at the interface.

[0013] The invention employs a four-step preparation process, with each step closely linked to achieve the goal of synergistic enhancement of the interface.

[0014] S1 dry pre-activation step: Surface-modified needle-like wollastonite and an ethylene-acrylate copolymer containing maleic anhydride groups were heated and mixed in a high-speed mixer. During mixing, frictional heat raised the material temperature to 60-80 degrees Celsius, inducing a ring-opening esterification reaction between the hydroxyl groups on the wollastonite surface and the maleic anhydride groups, generating a stable SiOC covalent bond structure. The grafting rate of this reaction can reach over 25%. The mixing time was controlled between 5 and 20 minutes to ensure a complete reaction and avoid thermal degradation of the copolymer.

[0015] S2 main melt blending steps: ABS resin, the surface-activated compound prepared from S1, and processing aids are added through the main feed port of a twin-screw extruder. The twin-screw has an aspect ratio of not less than 32, and a high-shear mixing section is included in the screw assembly, with a shear rate of 1500 to 2500 rpm to ensure uniform dispersion of wollastonite in the matrix. The temperature gradient of the first to ninth zones of the extruder is set to 190 to 230 degrees Celsius. The screw speed is 250 to 350 rpm, controlling the material residence time in the extruder to 2 to 3 minutes.

[0016] S3 Interface Precise Adjustment Steps: Epoxidized soybean oil is injected into the melting section of the extruder via a side-feeding device. The side-feeding position is selected in the third to sixth temperature control zones, where the melt viscosity is 2000 to 3000 Pascals, creating a suitable viscosity difference with the epoxidized soybean oil viscosity of 50 to 80 millipascals.

[0017] Under the shear flow field of the screw, low-viscosity ESO migrates to the high-shear region and selectively accumulates on the surface of wollastonite particles. An injection pressure of 0.2 to 0.6 MPa ensures that the ESO stably enters the melt without disrupting the existing chemical bonds.

[0018] S4 devolatilization granulation steps: The melt passes through a vacuum devolatilization zone to remove residual small-molecule volatiles. The vacuum level is no higher than -0.06 MPa. After devolatilization, the melt is hot-cut into pellets using a die or by pulling strips to obtain the granules of the composition of this invention. Attached Figure Description

[0019] Figure 1 This is a complete process flow diagram of the present invention, from raw material pretreatment to finished product granulation. Detailed Implementation Example 1

[0020] 20 parts by weight of alpha-wollastonite surface-modified with gamma-aminopropyltriethoxysilane and 10 parts by weight of ethylene-butyl acrylate-maleic anhydride terpolymer were added to a high-speed mixer. Wollastonite has the chemical formula CaSiO3, an aspect ratio of 14:1, and a D... 90 The copolymer contains 3.2 wt% maleic anhydride, 20 wt% butyl acrylate, and M... n The PDI was 2.0 and the mixer speed was set to 800 rpm. The mixing temperature was raised to 70 degrees Celsius, and the mixing time was 12 minutes to obtain the surface-activated composite. 100 parts by weight of ABS resin, the surface-activated composite, 0.4 parts by weight of antioxidant pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 0.3 parts by weight of lubricant ethylene bis-stearamide were added to a twin-screw extruder through the main feed port. The extruder length-to-diameter ratio was 36, the screw speed was 300 rpm, and the temperatures of zones one through nine were set to 190 degrees Celsius, 200 degrees Celsius, 210 degrees Celsius, 220 degrees Celsius, 220 degrees Celsius, 215 degrees Celsius, 210 degrees Celsius, 200 degrees Celsius, and 190 degrees Celsius, respectively. In zone five, 1.2 parts by weight of epoxidized soybean oil with an epoxy value of 6.2 and an epoxy equivalent of 185 g / mol was injected through a side feeder. The injection pressure is 0.35 MPa. A vacuum devolatilization device is installed in zone eight, with a vacuum degree of -0.07 MPa. The melt is then pelletized using a stranding process to obtain granules of the composition of this invention.

[0021] The granules were dried at 80°C for 4 hours and then injection molded into standard samples. The injection molding machine barrel temperature was 210-230°C, and the mold temperature was 60°C. The samples were conditioned at 23°C and 50% relative humidity for 48 hours before performance testing. Tensile strength testing was conducted according to GB / T1040.2, impact strength testing according to GB / T1843, flexural modulus testing according to GB / T9341, and heat distortion temperature testing according to GB / T1634.2. Interface coverage was determined by X-ray photoelectron spectroscopy, and grafting rate was determined by Fourier transform infrared spectroscopy. The test results were: tensile strength 62 MPa, impact strength 35 kJ / m², flexural modulus 2500 MPa, heat distortion temperature 96°C, interface coverage 87%, and grafting rate 28%. Example 2

[0022] 18 parts by weight of surface-modified alpha-wollastonite and 9 parts by weight of ethylene-butyl acrylate-maleic anhydride copolymer were added to a high-speed mixer. The wollastonite had an aspect ratio of 12:1, D 90 The size is 8 micrometers. The copolymer contains 3.0 wt% maleic anhydride and 18 wt% butyl acrylate. n The PDI was 1.8 and the ABS resin content was 25000. The mixing temperature was 65 degrees Celsius, and the mixing time was 10 minutes. The mixture contained 100 parts ABS resin, 0.3 parts antioxidant, and 0.2 parts lubricant. The extrusion process was the same as in Example 1, with 0.8 parts ESO, an epoxy value of 6.0, an epoxy equivalent of 180 g / mol, and an injection pressure of 0.25 MPa. The resulting composition had a tensile strength of 58 MPa, an impact strength of 32 kJ / m², a flexural modulus of 2320 MPa, a heat distortion temperature of 93 degrees Celsius, an interface coverage of 65%, and a grafting rate of 22%. Example 3

[0023] 22 parts by weight of alpha-wollastonite surface-modified with gamma-aminopropyltriethoxysilane and 11 parts by weight of ethylene-butyl acrylate-maleic anhydride terpolymer were added to a high-speed mixer. The wollastonite used had the chemical formula CaSiO3, with an aspect ratio strictly controlled at 15:1 and a particle size distribution D. 90 The surface hydroxyl content, measured by titration, is 0.82 mmol / g, with a micrometer diameter of 15 micrometers. The copolymer contains 3.5 wt% maleic anhydride grafting and 22 wt% butyl acrylate segments, with a number-average molecular weight M... nThe molecular weight distribution index (PDI) was 2.3, and the characteristic peak of the anhydride was located at 1780 cm⁻¹, with a value of 35,000. The mixing temperature was set to 75 degrees Celsius, and the mixing time was extended to 15 minutes to ensure sufficient frictional heat to initiate the interfacial reaction. 100 parts by weight of ABS resin, a surface-activated compound, 0.5 parts by weight of the antioxidant pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 0.4 parts by weight of the lubricant ethylene bis-stearamide were added to a twin-screw extruder through the main feed port. The extruder had an aspect ratio of 36, a screw speed of 350 rpm, and a shear rate increased to 2500 rpm. The temperature gradients for zones one through nine were set to 195 degrees Celsius, 205 degrees Celsius, 215 degrees Celsius, 225 degrees Celsius, 225 degrees Celsius, 220 degrees Celsius, 215 degrees Celsius, 205 degrees Celsius, and 195 degrees Celsius. In zone six, 1.5 parts by weight of epoxidized soybean oil with an epoxy value of 6.5 and an epoxy equivalent of 190 g / mol was injected via a side-feeding device at an injection pressure of 0.55 MPa. Zone eight had a vacuum of -0.075 MPa. The resulting granular composition was tested by injection molding and showed the following results: tensile strength 64 MPa, impact strength 33 kJ / m², flexural modulus 2680 MPa, heat distortion temperature 98°C, interface coverage 92%, grafting rate 32%, melt flow index 22 g / 10 min, surface gloss 92 GU, and no flow marks or defects. Example 4

[0024] 20 parts by weight of surface-modified alpha-wollastonite and 10 parts by weight of ethylene-butyl acrylate-maleic anhydride copolymer were added to a high-speed mixer. The raw material specifications and pre-activation process parameters were the same as in Example 1. This example focuses on the effect of the side feed position on the interface control effect. After the surface-activated compound, ABS resin, antioxidant, and lubricant were added to the twin-screw extruder through the main feed port, the side feed position of the epoxidized soybean oil was adjusted from the preferred fifth zone to the third zone. The melt temperature in the third zone was set to 210 degrees Celsius, the viscosity to approximately 2500 Pa·s, and the injection pressure was reduced to 0.3 MPa to match the lower melt pressure in this zone. Other process parameters, such as screw speed of 300 rpm, vacuum degree of -0.07 MPa, and temperature gradient, remained consistent with Example 1. Due to the relatively low shear rate in the third zone, the ESO migration efficiency decreased, the interface coverage decreased to 75%, and the grafting rate was 25%. The injection-molded sample test results showed a tensile strength of 61 MPa, an impact strength of 31 kJ / m², a flexural modulus of 2480 MPa, a heat distortion temperature of 94 degrees Celsius, and a melt flow index of 19 g / 10 min. Compared with Example 1, the impact strength decreased by 6%, proving that the fifth zone side feeding position is the optimal position. This comparative data indicates that the choice of side feeding position directly affects the distribution behavior of ESO in the melt flow field. Premature injection causes ESO to be sheared and dispersed into the matrix in the subsequent mixing stage, failing to achieve targeted enrichment at the interface, thus weakening the construction effect of the interface transition layer.

[0025] Comparative Example 1 20 parts by weight of surface-modified alpha-wollastonite, 10 parts by weight of copolymer, 100 parts by weight of ABS resin, 0.4 parts by weight of antioxidant, and 0.3 parts by weight of lubricant were all added through the main feed port; ESO was not added. The extrusion temperature and screw parameters were the same as in Example 1. The resulting composition had a tensile strength of 58 MPa, an impact strength of 22 kJ / m², and an interface coverage of 40%. Compared with Example 1, the impact strength decreased by 37%, demonstrating the necessity of ESO interface control.

[0026] Comparative Example 2 20 parts by weight of surface-modified alpha-wollastonite, 100 parts of ABS resin, 5 parts of conventional ABS grafted maleic anhydride compatibilizer, 0.4 parts of antioxidant, and 0.3 parts of lubricant were added via the main feed, and 1.2 parts of ESO were injected via the side feed. Extrusion parameters were the same as in Example 1. The resulting composition had a tensile strength of 57 MPa, an impact strength of 26 kJ / m², and an interface coverage of 55%. Compared to Example 1, the impact strength was 26% lower, demonstrating the additional toughening contribution of the flexible segments of the ethylene acrylate copolymer.

[0027] Comparative Example 3 100 parts ABS resin, 10 parts copolymer, 1.2 parts ESO, 0.4 parts antioxidant, and 0.3 parts lubricant were added via the main feedstock, without adding wollastonite. The remaining processes were the same as in Example 1. The resulting composition had a tensile strength of 45 MPa and an impact strength of 28 kJ per square meter. Compared to Example 1, the tensile strength was 27% lower, demonstrating the indispensable reinforcing effect of the acicular wollastonite rigid framework.

[0028] Comparative Example 4 Twenty parts of unmodified ordinary alpha-wollastonite were mixed with 10 parts of the copolymer at high speed, with the mixing temperature and time the same as in Example 1. One hundred parts of ABS resin, the mixture, 1.2 parts of ESO, 0.4 parts of antioxidant, and 0.3 parts of lubricant were added via the main feed of an extruder, with the remaining processes the same as in Example 1. The resulting composition had a tensile strength of 56 MPa, an impact strength of 20 kJ / m², and an interfacial coverage of 35%. Compared to Example 1, the impact strength was 43% lower, demonstrating the importance of the pre-activation reaction of the hydroxyl groups on the silane-modified wollastonite surface for interfacial strength.

[0029] Comparative Example 5 A surface-activated composite was obtained by high-speed mixing of 20 parts of surface-modified alpha-wollastonite and 10 parts of copolymer. 100 parts of ABS resin, the surface-activated composite, 0.4 parts of antioxidant, and 0.3 parts of lubricant were added via a main feedstock, without adding ESO. The remaining processes were the same as in Example 1. The resulting composition had a tensile strength of 60 MPa, an impact strength of 22 kJ / m², and an interface coverage of 45%. Compared to Example 1, the impact strength was 37% lower, demonstrating that the flexible interfacial transition layer constructed from epoxidized soybean oil is crucial for improving toughness.

[0030] The compositions of this invention have significant advantages over existing technologies. Comparative Example 1, using ESO added to the main feedstock, achieved an impact strength of only 24 kJ / m², a 31% reduction compared to Example 1, demonstrating the necessity of interface control in the side-feeding process. Comparative Example 2, using conventional ABS grafted with maleic anhydride compatibilizer, achieved an impact strength of 26 kJ / m², 26% lower than Example 1, demonstrating the additional toughening contribution of the flexible segments of the ethylene-acrylate copolymer. Comparative Example 3, without the addition of wollastonite, achieved a tensile strength of 45 MPa, 27% lower than Example 1, demonstrating the reinforcing effect of the rigid skeleton. Comparative Example 4, using unactivated ordinary wollastonite, achieved an impact strength of 20 kJ / m², 43% lower than Example 1, demonstrating the crucial role of interfacial chemical bonding. Comparative Example 5, without the addition of ESO, achieved an impact strength of 22 kJ / m², 37% lower than Example 1, demonstrating the indispensability of a complete interfacial transition layer.

[0031] The performance test data of the above embodiments and comparative examples show that Embodiment 1 is the preferred embodiment of the present invention, with its tensile strength and impact strength reaching the highest values ​​simultaneously. Embodiments 2 to 4, with adjustments to component content or process parameters, have slightly lower performance than Embodiment 1, but are still significantly better than all comparative examples. Comparative Examples 1 to 5 each exclude a key technical feature of the present invention, and their performance all show a significant decrease, proving that there is a synergistic effect among the components and process steps described in the present invention, and none can be omitted.

Claims

1. A high-strength, high-toughness ABS resin composition, characterized in that, Composed of the following components in parts by weight: 100 parts of ABS resin; 18 to 22 parts of alpha-wollastonite surface-modified with gamma-aminopropyltriethoxysilane; 9 to 11 parts of ethylene butyl acrylate maleic anhydride terpolymer; 0.8 to 1.5 parts of epoxidized soybean oil; 0.3 to 0.5 parts of antioxidant; 0.2 to 0.4 parts of lubricant; wherein the wollastonite and copolymer are pre-activated by dry process to form an interfacial chemical bond structure, and the epoxidized soybean oil is selectively distributed in the interfacial region between the wollastonite and the ABS matrix to form a flexible transition layer with a thickness of 30 to 80 nanometers.

2. The ABS resin composition according to claim 1, characterized in that, The surface-modified alpha-wollastonite has the chemical formula CaSiO3, an aspect ratio of 12:1 to 15:1, and a particle size distribution D. 90 It is 8 to 15 micrometers in size.

3. The ABS resin composition according to claim 1, characterized in that, The number-average molecular weight M of the ethylene butyl acrylate maleic anhydride terpolymer n The molecular weight distribution index (PDI) is 1.8 to 2.3, with a maleic anhydride grafting rate of 3.0 to 3.5 wt% and a butyl acrylate segment content of 18 to 22 wt%.

4. The ABS resin composition according to claim 1, characterized in that, The epoxidized soybean oil has an epoxy value of 6.0 to 6.5, an acid value of less than 0.5 mg KOH per gram, and an epoxy equivalent of 180 to 190 g per mole; the composition has a tensile strength of not less than 62 MPa, an impact strength of not less than 35 kJ per square meter, a flexural modulus of not less than 2500 MPa, and an interfacial chemical bonding saturation of greater than 85%.

5. A method for preparing the ABS resin composition according to any one of claims 1 to 4, characterized in that... Includes the following steps: In the S1 dry pre-activation step, surface-modified alpha-wollastonite and ethylene butyl acrylate maleic anhydride terpolymer are mixed in a high-speed mixer at 60 to 80 degrees Celsius for 5 to 20 minutes. The surface-activated composite is obtained by inducing interfacial chemical reaction through frictional heat. In the S2 main melt blending step, ABS resin, the surface-activating compound and processing aids are added through the main feed port of a twin-screw extruder and melt blended at 190 to 230 degrees Celsius. S3 interface precise control steps, epoxidized soybean oil is injected into the melting section of the extruder through a side feeding device; In the S4 devolatilization and granulation step, the ABS resin composition is obtained by vacuum devolatilization at a vacuum degree not exceeding -0.06 MPa followed by pelletizing.

6. The preparation method according to claim 5, characterized in that, The high-speed mixer in step S1 operates at a speed of 800 revolutions per minute, a mixing temperature of 70 degrees Celsius, and a mixing time of 12 minutes. The grafting rate of the interfacial chemical reaction is above 25%.

7. The preparation method according to claim 5, characterized in that, The twin-screw extruder described in step S2 has an aspect ratio of not less than 32, a screw speed of 250 to 350 revolutions per minute, a shear rate of 1500 to 2500 per second, and a material residence time in the extruder of 2 to 3 minutes.

8. The preparation method according to claim 5, characterized in that, In step S3, the side-feeding device is located in the third to sixth temperature control zones of the twin-screw extruder. The epoxidized soybean oil injection pressure is 0.2 to 0.6 MPa. Under the action of the melt shear flow field, the epoxidized soybean oil is selectively enriched on the surface of wollastonite particles.

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