Scratch-resistant high-toughness HIPS (High Impact Polystyrene) material and preparation method thereof

Abstract

The invention relates to the technical field of HIPS material processing, in particular to a scratch-resistant and good-toughness HIPS material and a preparation method thereof.The scratch-resistant and good-toughness HIPS material is prepared from, by weight, 60-70 parts of high impact polystyrene, 15-20 parts of polyethylene, 2-3 parts of styrene butadiene rubber, 4-7 parts of polyether-polyamide block copolymer, 20-35 parts of scratch-resistant agent and 3-5 parts of flexibilizer. Wherein the polyethylene is formed by compounding three kinds of polyethylene with the melt flow rates of 0.5-1 g / 10 min, 2-3 g / 10 min and 3-5 g / 10 min respectively. The density of the material is improved through the low-melt-flow-rate polyethylene, the interfacial compatibility is optimized through the medium-melt-flow-rate polyethylene, the processing fluidity is guaranteed through the high-melt-flow-rate polyethylene, and the forming processing performance and the structural stability are improved through the cooperation of the low-melt-flow-rate polyethylene, the medium-melt-flow-rate polyethylene and the high-melt The butadiene styrene rubber, the polyether-polyamide block copolymer and the flexibilizer have a synergistic effect to improve the low-temperature toughness; and the scratch-resistant agent synchronously improves the surface hardness and the scratch resistance. The prepared material has excellent scratch resistance and low-temperature toughness, and can be used in an environment of-20 DEG C to-40 DEG C.

Description

Technical Field

[0001] This application relates to the field of HIPS material processing technology, and more specifically, to a scratch-resistant and tough HIPS material and its preparation method. Background Technology

[0002] High-impact polystyrene (HIPS) is an important thermoplastic resin material, prepared by blending and modifying polystyrene with rubber elastomers. Due to its combination of the good rigidity, easy processability, and low cost of polystyrene with the impact resistance imparted by the rubber phase, HIPS materials have been widely used in automotive interior parts, household appliance housings, office equipment, electronic and electrical products, and packaging materials.

[0003] However, as downstream applications continue to demand higher product performance, the inherent defects of traditional HIPS materials are becoming increasingly apparent, mainly in the following aspects: First, insufficient surface hardness results in poor scratch resistance. Traditional HIPS materials typically have low surface hardness, making them easily scratched by sharp objects during daily use. This scratches not only affect the product's appearance and reduce user experience but can also lead to stress concentration and crack propagation, shortening the product's lifespan. Especially in applications with stringent appearance requirements, such as automotive interiors and high-end appliance casings, scratch resistance has become a key indicator of material quality.

[0004] Secondly, HIPS exhibits poor low-temperature toughness and a significant decrease in impact strength. Although HIPS materials possess good impact resistance at room temperature, their high glass transition temperature restricts molecular chain movement at low temperatures (e.g., -20°C to -40°C), leading to a sharp decline in toughness and a significant increase in brittleness. This defect severely limits the application of HIPS materials in cold regions or low-temperature conditions, such as outdoor electrical equipment, cryogenic transport packaging, and automotive exterior parts.

[0005] The aforementioned technical limitations have significantly restricted the application of HIPS materials in high-end markets and special environments. Therefore, how to effectively improve the surface hardness and low-temperature toughness of HIPS materials while maintaining their original cost advantages and processing performance has become an urgent problem to be solved. Summary of the Invention

[0006] To address the issues of insufficient surface hardness and poor low-temperature toughness of HIPS, this application provides a scratch-resistant and tough HIPS material and its preparation method.

[0007] In a first aspect, this application provides a scratch-resistant and tough HIPS material, employing the following technical solution: A scratch-resistant and tough HIPS material is prepared from the following raw materials in parts by weight: 60-70 parts of high-impact polystyrene 15-20 parts of polyethylene 2-3 parts styrene-butadiene rubber 4-7 parts of polyether-polyamide block copolymer 20-35 parts of scratch-resistant agent 3-5 parts toughening agent The polyethylene is composed of polyethylene I, polyethylene II and polyethylene III; The melt flow rate of polyethylene I at 190℃ / 2.16kg is 0.5-1g / 10min; The melt flow rate of polyethylene II at 190℃ / 2.16kg is 2-3g / 10min; The melt flow rate of polyethylene III at 190℃ / 2.16kg is 3-5g / 10min.

[0008] By adopting the above technical solution, the resulting scratch-resistant and tough HIPS material has good hardness and scratch resistance, which can reduce the damage to products caused by sharp objects during use. It can meet the use requirements of demanding scenarios such as automotive interiors and high-end home appliance shells. At the same time, the low-temperature toughness of the material is optimized, reducing the tendency of the material to become brittle and minimizing the decrease in impact strength at low temperatures. This allows it to be used in low-temperature environments ranging from -20℃ to -40℃, meeting the application scenarios in cold regions such as outdoor electrical appliances, low-temperature transport packaging, and automotive external parts.

[0009] This application utilizes a blend of three polyethylenes with different melt flow rates. Low melt flow rate polyethylene I improves the density of the material's internal structure; medium melt flow rate polyethylene II optimizes the interfacial compatibility between the matrix and other components; and high melt flow rate polyethylene III ensures the overall processing fluidity of the material. These three components synergistically regulate the material's molding and processing performance and internal structural stability. Styrene-butadiene rubber (SBR), polyether-polyamide block copolymer, and toughening agents work synergistically. SBR supplements the rubber phase's toughness enhancement capabilities, polyether-polyamide block copolymer improves the molecular chain mobility at low temperatures, and the toughening agent further strengthens the material's impact resistance. All three components work together to alleviate the embrittlement problem at low temperatures. A scratch-resistant agent enhances the material's surface hardness and scratch resistance, and helps optimize the material's rigidity without negatively impacting the original processing performance and cost advantages of the matrix material. Ultimately, this achieves a simultaneous improvement in scratch resistance and low-temperature toughness.

[0010] Preferably, the weight ratio of polyethylene I, polyethylene II and polyethylene III is 5:(4-6):(2-4).

[0011] By adopting the above technical solution, polyethylene I, with the highest proportion, is used as the core of the compound, giving full play to its structural compactness brought about by its low melt flow rate, providing a stable internal structural foundation for the material. Polyethylene II, with a proportion in the middle range, can adapt to the interfacial bonding requirements of the matrix and other functional components, optimize the transition effect between polyethylenes with different melt flow rates, and at the same time improve the compatibility of high-impact polystyrene matrix with rubber phase, scratch-resistant agents and other components. Polyethylene III, with a relatively low proportion, can ensure that the material has good processing fluidity without compromising the overall structural compactness. The balance of the proportions of the three can make their respective performance advantages complement each other, making the molding and processing process of the material more stable, the internal components more uniformly dispersed, and thus helping to enhance the scratch resistance of the scratch-resistant agent. At the same time, it optimizes the movement space of molecular chains in low-temperature environments, further improving the low-temperature toughness of the material.

[0012] Preferably, the scratch-resistant agent is prepared by the following method: 1) Disperse nano boron nitride and nano aluminum oxide in anhydrous ethanol, adjust the pH to 4.0-4.5 with hydrochloric acid, reflux and stir at 65-70℃ for 1-2 hours, filter, and dry to obtain hydroxylated nano boron nitride and hydroxylated nano aluminum oxide. 2) Hydroxylated boron nitride nanoparticles and hydroxylated alumina nanoparticles were dispersed in ethanol, ultrasonically dispersed, and 3-aminopropyltriethoxysilane and glacial acetic acid were added dropwise. The mixture was reacted at 60-65℃ for 5-6 hours, filtered, and washed to obtain aminated boron nitride nanoparticles and aminated alumina nanoparticles. 3) Disperse aminated boron nitride nanoparticles and aminated alumina nanoparticles in toluene, sonicate, add octamethylcyclotetrasiloxane and tetramethylammonium hydroxide, heat to 105-110℃, react under nitrogen protection for 6-8h, cool to room temperature, and centrifuge to obtain the product; 4) Mix the product with polyester-modified silicone to obtain a scratch-resistant agent.

[0013] Preferably, the raw materials used to prepare the scratch-resistant agent are in the following weight proportions: 40-50 parts of nano boron nitride 15-25 parts of nano-alumina 10-15 parts of 3-aminopropyltriethoxysilane 1-2 parts glacial acetic acid 15-20 parts of octamethylcyclotetrasiloxane 0.2-0.5 parts of tetramethylammonium hydroxide 20-30 parts of polyester-modified silicone.

[0014] By adopting the above technical solution, the scratch-resistant agent is uniformly dispersed in the HIPS matrix, and can be well compatible with polyethylene compound system, fillers, etc., improving the surface hardness and scratch resistance of the material, reducing scratch marks from sharp objects, while not affecting the low-temperature toughening effect of toughening components and the material processing fluidity, making the scratch resistance of the final HIPS material more stable and durable.

[0015] Hydroxylation introduces active hydroxyl groups into nano-boron nitride and nano-alumina, providing reaction sites for subsequent modification and initially improving particle dispersibility. Aminoation modification introduces amino groups, building a bridge between the inorganic particles and the HIPS organic matrix, significantly improving the interfacial compatibility between the scratch-resistant agent and the high-impact polystyrene / polyethylene composite system, and preventing particle aggregation. Siloxane grafting modification further optimizes the hydrophobicity and dispersion stability of the particles, while the siloxane segments improve surface lubrication and reduce the scratching force from sharp objects. Finally, when compounded with polyester-modified silicone, the two form a complementary scratch-resistant structure. The polyester-modified silicone fills the gaps between the inorganic particles, further enhancing the surface's wear and scratch resistance.

[0016] Preferably, the average particle size of the nano-boron nitride is 100-300 nm, and the average particle size of the nano-alumina is 400-800 nm.

[0017] By adopting the above technical solution, 100-300nm nano-boron nitride can fill the gaps in 400-800nm ​​nano-alumina, improving the structural density of the scratch-resistant agent. Both can be uniformly dispersed in the HIPS matrix, significantly enhancing the interfacial bonding force with the matrix, thereby strengthening the surface hardness of the material and reducing scratches caused by sharp objects without excessively increasing material brittleness. Furthermore, they can synergistically work with compound toughening agents and polyether-polyamide block copolymers to maintain the molecular chain activity at low temperatures, ensuring low-temperature toughness.

[0018] Preferably, the toughening agent is composed of methyl acrylate-butadiene-styrene copolymer and maleic anhydride-grafted SEBS in a weight ratio of (3-5):1.

[0019] By adopting the above technical solution, methyl acrylate-butadiene-styrene copolymer can maintain good elasticity in low-temperature environments ranging from -20℃ to -40℃, alleviating the problem of restricted molecular chain movement and directly improving low-temperature impact resistance. Maleic anhydride grafted SEBS optimizes the interfacial compatibility between the toughening agent and the high-impact polystyrene matrix and polyethylene composite system, allowing the toughening components to be uniformly dispersed. The 3-5:1 ratio balances the toughening effect and interfacial compatibility, making the toughening effect stable and long-lasting, while not interfering with the scratch resistance of the scratch-resistant agent or damaging the original processing fluidity of the material.

[0020] Preferably, the polyether-polyamide block copolymer has the structural formula PA-b-PEG-b-PA and / or PA-b-PPG-b-PA.

[0021] By adopting the above technical solutions, the PA segments can improve the interfacial compatibility with the high-impact polystyrene matrix and polyethylene compound system, ensuring its uniform dispersion in the material; the PEG or PPG flexible polyether segments can maintain good chain mobility in low-temperature environments ranging from -20℃ to -40℃, alleviating the problem of molecular chain restriction in traditional HIPS materials at low temperatures and effectively improving low-temperature impact resistance. Simultaneously, its block structure can synergistically enhance the toughening effect with the compound toughening agent, assisting in optimizing the dispersion state of the filler without interfering with the scratch resistance of the scratch-resistant agent.

[0022] Preferably, the styrene-butadiene rubber has a styrene content of 22.5-24.5% and a Mooney viscosity of 48-56.

[0023] By adopting the above technical solution, a styrene content of 22.5-24.5% can be adapted to the compositional characteristics of high-impact polystyrene matrix, improving interfacial compatibility with the matrix and polyethylene compound system, and ensuring its uniform dispersion in the material; a Mooney viscosity range of 48-56 can balance processing flowability and the elastic properties of the rubber phase, avoiding excessive viscosity interfering with the overall material processing, or excessively low viscosity leading to insufficient toughening effect. It can synergistically work with compound toughening agents and polyether-polyamide block copolymers to alleviate the problem of restricted molecular chain movement and enhance low-temperature toughness in low-temperature environments ranging from -20℃ to -40℃.

[0024] Preferably, the melt flow rate of the polyethylene I at 190°C / 2.16 kg is 0.7 g / 10 min; The melt flow rate of the polyethylene II at 190℃ / 2.16kg is 2.6g / 10min; The melt flow rate of the polyethylene III at 190℃ / 2.16kg is 4.1g / 10min.

[0025] By adopting the above technical solutions, the parameters of polyethylene I, polyethylene II and polyethylene III are further optimized, the scratch resistance and hardness of the materials are further improved, and the movement space of molecular chains at low temperatures is optimized by combining toughening components, thereby stabilizing and improving the low-temperature toughness of the materials.

[0026] Secondly, this application provides a method for preparing a scratch-resistant and tough HIPS material, using the following technical solution: A method for preparing a scratch-resistant and tough HIPS material includes the following preparation steps: S1. Mix dried high-impact polystyrene, polyethylene, styrene-butadiene rubber and polyether-polyamide block copolymer, then add scratch-resistant agent and toughening agent and mix to obtain a mixture; S2. The mixture is then placed in a twin-screw extruder, extruded, and granulated to obtain a scratch-resistant and tough HIPS material.

[0027] By adopting the above technical solution, the combination of staged mixing and twin-screw extrusion can fully ensure the synergistic performance of each component: S1 staged mixing first fully integrates the matrix raw materials to build a stable premixed matrix system, and then adds functional components, which can avoid the agglomeration of scratch-resistant agents and ensure that each component is evenly dispersed in the matrix; S2 twin-screw extrusion's strong shearing and plasticizing effect can enhance the interfacial bonding effect of each component, allowing the structural regulation of the polyethylene compound system, the low-temperature toughening of toughening components, and the hardness improvement of scratch-resistant fillers to be fully released, and finally the scratch resistance and low-temperature toughness of the HIPS material are stably improved.

[0028] In summary, this application has the following beneficial effects: 1. This application optimizes processing fluidity and structural density by blending three polyethylenes with different melt flow rates. Low melt flow rate polyethylene I enhances internal density, medium melt flow rate polyethylene II improves interfacial compatibility, and high melt flow rate polyethylene III ensures molding and processing performance. The synergistic effect of styrene-butadiene rubber, polyether-polyamide block copolymer, and toughening agent further enhances impact strength in low-temperature environments from -20℃ to -40℃, effectively mitigating the material's embrittlement tendency. The scratch-resistant agent significantly improves surface hardness and scratch resistance, meeting the stringent appearance requirements of automotive interiors and high-end appliance casings. This material maintains cost advantages and processing performance while possessing high rigidity, excellent low-temperature toughness, and scratch resistance, making it suitable for extreme conditions such as outdoor electrical appliances in cold regions, low-temperature transport packaging, and automotive exterior parts. Detailed Implementation Example

[0029] The high-impact polystyrene was purchased from Zhenjiang Chimei Chemical Co., Ltd., model number PH-88HT.

[0030] The methyl acrylate-butadiene-styrene copolymer was purchased from Shandong Donglin New Material Co., Ltd., model DL-521S.

[0031] Maleic anhydride-grafted SEBS is a product of Kraton FG1901 from the United States.

[0032] The polyester-modified silicone is silicone-based silicone 5140. Example

[0033] A scratch-resistant and tough HIPS material is prepared by the following method: S1. Mix 600g of dried high-impact polystyrene, 150g of polyethylene, 20g of styrene-butadiene rubber and 40g of polyether-polyamide block copolymer, then add 200g of scratch-resistant agent and 30g of toughening agent and mix to obtain a mixture. Polyethylene is composed of polyethylene I, polyethylene II and polyethylene III in a weight ratio of 5:4:2; The melt flow rate of polyethylene I at 190℃ / 2.16kg is 0.5g / 10min; The melt flow rate of polyethylene II at 190℃ / 2.16kg is 2g / 10min; The melt flow rate of polyethylene III at 190℃ / 2.16kg is 3g / 10min; The toughening agent is composed of methyl acrylate-butadiene-styrene copolymer and maleic anhydride-grafted SEBS in a weight ratio of 3:1; The polyether-polyamide block copolymer has the structural formula PA-b-PEG-b-PA and a molecular weight of 5000. The styrene-butadiene rubber has a styrene content of 22.5% and a Mooney viscosity of 48. The scratch-resistant agent is composed of nano boron nitride and nano aluminum oxide in a weight ratio of 4:3; S2. The mixture is then placed in a twin-screw extruder, extruded, and granulated to obtain a scratch-resistant and tough HIPS material.

[0034] The difference between Examples 2-3 and Example 1 lies in the types, amounts, and parameters of raw materials used to prepare the scratch-resistant and tough HIPS material. Specific differences are shown in Table 1. Table 1. Raw material types, dosages, and parameters for preparing scratch-resistant and tough HIPS materials.

[0035] In Example 2, the polyethylene is composed of polyethylene I, polyethylene II, and polyethylene III in a weight ratio of 5:5:3; The melt flow rate of polyethylene I at 190℃ / 2.16kg is 0.8g / 10min; The melt flow rate of polyethylene II at 190℃ / 2.16kg is 2.5g / 10min; The melt flow rate of polyethylene III at 190℃ / 2.16kg is 4g / 10min; In Example 3, the polyethylene was composed of polyethylene I, polyethylene II, and polyethylene III in a weight ratio of 5:6:4. The melt flow rate of polyethylene I at 190℃ / 2.16kg is 1g / 10min; The melt flow rate of polyethylene II at 190℃ / 2.16kg is 3g / 10min; The melt flow rate of polyethylene III at 190℃ / 2.16kg is 5g / 10min; Example

[0036] A scratch-resistant and tough HIPS material, the difference between this embodiment and Example 1 is that the scratch-resistant agent is prepared by the following method: 200g of nano boron nitride and 150g of nano aluminum oxide were dispersed in 1500ml of anhydrous ethanol, the pH was adjusted to 4.0 with hydrochloric acid, and the mixture was refluxed and stirred at 65℃ for 1h. After filtration and drying, hydroxylated nano boron nitride and hydroxylated nano aluminum oxide were obtained. The average particle size of the boron nitride nanoparticles is 100 nm, and the average particle size of the alumina nanoparticles is 400 nm. 2) Hydroxylated boron nitride nanoparticles and hydroxylated alumina nanoparticles were dispersed in 1500 ml of ethanol, ultrasonically dispersed, and 50 g of 3-aminopropyltriethoxysilane and 5 g of glacial acetic acid were added dropwise. The mixture was reacted at 60 °C for 5 h, filtered, and washed to obtain aminated boron nitride nanoparticles and aminated alumina nanoparticles. 3) Disperse aminated boron nitride nanoparticles and aminated alumina nanoparticles in 1000 ml of toluene, sonicate, add 75 g of octamethylcyclotetrasiloxane and 1 g of tetramethylammonium hydroxide, heat to 105 °C, react for 6 h under nitrogen protection, cool to room temperature, and centrifuge to obtain the product. 4) Mix the product with 100g of polyester-modified silicone to obtain a scratch-resistant agent.

[0037] Example 5 A scratch-resistant and tough HIPS material, the difference between this embodiment and Example 1 is that the scratch-resistant agent is prepared by the following method: 250g of nano boron nitride and 125g of nano aluminum oxide were dispersed in 2000ml of anhydrous ethanol, the pH was adjusted to 4.5 with hydrochloric acid, and the mixture was refluxed and stirred at 70℃ for 2h. After filtration and drying, hydroxylated nano boron nitride and hydroxylated nano aluminum oxide were obtained. The average particle size of the boron nitride nanoparticles is 300 nm, and the average particle size of the alumina nanoparticles is 800 nm. 2) Hydroxylated boron nitride nanoparticles and hydroxylated alumina nanoparticles were dispersed in 2000 ml of ethanol, ultrasonically dispersed, and 75 g of 3-aminopropyltriethoxysilane and 10 g of glacial acetic acid were added dropwise. The mixture was reacted at 65 °C for 6 h, filtered, and washed to obtain aminated boron nitride nanoparticles and aminated alumina nanoparticles. 3) Aminated boron nitride nanoparticles and aminated alumina nanoparticles were dispersed in 1200 ml of toluene, sonicated, 100 g of octamethylcyclotetrasiloxane and 2.5 g of tetramethylammonium hydroxide were added, the temperature was raised to 110 °C, and the reaction was carried out under nitrogen protection for 8 h. After cooling to room temperature, the product was obtained by centrifugation. 4) Mix the product with 150g of polyester-modified silicone to obtain a scratch-resistant agent.

[0038] Example 6 A scratch-resistant and tough HIPS material, the difference between this embodiment and Example 1 is that the toughening agent is methyl acrylate-butadiene-styrene copolymer.

[0039] Example 7 A scratch-resistant and tough HIPS material, the difference between this embodiment and Example 1 is that the melt flow rate of polyethylene I under the condition of 190℃ / 2.16kg is 0.7g / 10min; The melt flow rate of polyethylene II at 190℃ / 2.16kg is 2.6g / 10min; The melt flow rate of polyethylene III at 190℃ / 2.16kg is 4.1g / 10min.

[0040] Example 8 A scratch-resistant and tough HIPS material, the difference between this embodiment and Embodiment 1 is that the weight ratio of polyethylene I, polyethylene II and polyethylene III is 2:4:2.

[0041] Comparative Example Comparative Example 1 A HIPS material, the difference between this comparative example and Example 1 is that the polyethylene has a melt flow rate of 0.5 g / 10 min at 190 °C / 2.16 kg.

[0042] Comparative Example 2 A HIPS material, the difference between this comparative example and Example 1 is that the polyethylene is composed of polyethylene I and polyethylene II in a weight ratio of 5:4.

[0043] Comparative Example 3 A HIPS material, the difference between this comparative example and Example 1 is that polyphenylene ether resin is used instead of styrene-butadiene rubber.

[0044] The polyphenylene ether resin is 540Z from Asahi Kasei Corporation of Japan.

[0045] Comparative Example 4 A HIPS material, the difference between this comparative example and Example 1 is that K-resin is used instead of polyether-polyamide block copolymer.

[0046] K-resin is KR-03, a product of Phillips Corporation, USA.

[0047] Comparative Example 5 A HIPS material, the difference between this comparative example and Example 1 is that talc is used instead of scratch-resistant agent.

[0048] Detection methods / test methods The scratch-resistant and tough HIPS materials obtained in Examples 1-8 and the HIPS materials obtained in Comparative Examples 1-5 were respectively made into sheets and subjected to the following tests: Hardness test: The surface hardness of the material is tested using a pencil hardness tester according to GB / T 6739 standard; Scratch depth test: The scratch depth was measured using a Taber abrasion tester with a CS-10 grinding wheel, a 1000g load, and 500 revolutions. Cantilever beam impact strength: According to GB / T 1843 standard, the impact strength is tested at three temperatures: -40℃, -20℃, and 23℃. Elongation at break: The tensile elongation at break was tested according to GB / T 1040 standard at -40℃, -20℃, and 23℃. Experimental data are shown in Table 2. Table 2 Experimental data of Examples 1-8 and Comparative Examples 1-5

[0049] The experimental data above show that the scratch-resistant and tough HIPS material prepared by the formulation of this application can simultaneously improve the scratch resistance and low-temperature toughness of HIPS material, effectively solving the problems of easy scratching and low-temperature embrittlement of traditional HIPS surfaces.

[0050] By comparing Example 1 with Comparative Examples 1-5, it is shown that by using a specific combination of polyethylene, styrene-butadiene rubber, polyether-polyamide block copolymer and scratch-resistant agent in synergy, this application can greatly improve the overall performance of HIPS materials, such as hardness, scratch resistance and low-temperature toughness retention.

[0051] A comparison of Examples 1 and 4-5 demonstrates that the nano-boron nitride / alumina composite scratch-resistant agent modified by hydroxylation-amylation-siloxane grafting can significantly improve the scratch resistance of HIPS materials without sacrificing low-temperature toughness.

[0052] Comparing Examples 1 and 6, it is shown that optimizing the type of toughening agent enables HIPS materials to maintain molecular chain activity more effectively in low-temperature environments ranging from -20°C to -40°C, thereby synergistically improving impact strength and elongation at break, overcoming the degradation of the toughening effect of a single methyl acrylate-butadiene-styrene copolymer at extreme low temperatures.

[0053] Examples 1 and 7 illustrate that optimizing the melt flow rate parameters of the three polyethylenes can simultaneously improve surface hardness and low-temperature toughness, achieving a better balance between rigidity and toughness. In Example 8, when the proportion of low melt flow rate polyethylene I was reduced from 5 parts to 2 parts, the hardness decreased to 1H, the scratch depth increased to 5.2μm, and the impact strength at -40℃ decreased to 6.8 kJ / m². This indicates that the low MFR characteristic of polyethylene I plays a key supporting role in maintaining the compactness of the material structure and its comprehensive performance, and its proportion should not be too low.

[0054] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A scratch-resistant and tough HIPS material, characterized in that, It is prepared from the following raw materials in parts by weight: 60-70 parts of high-impact polystyrene 15-20 parts of polyethylene 2-3 parts styrene-butadiene rubber 4-7 parts of polyether-polyamide block copolymer 20-35 parts of scratch-resistant agent 3-5 parts toughening agent The polyethylene is composed of polyethylene I, polyethylene II and polyethylene III; The melt flow rate of the polyethylene I at 190℃ / 2.16kg is 0.5-1g / 10min; The melt flow rate of the polyethylene II at 190℃ / 2.16kg is 2-3g / 10min; The melt flow rate of the polyethylene III at 190℃ / 2.16kg is 3-5g / 10min.

2. The scratch-resistant and tough HIPS material according to claim 1, characterized in that: The weight ratio of polyethylene I, polyethylene II and polyethylene III is 5:(4-6):(2-4).

3. The scratch-resistant and tough HIPS material according to claim 1, characterized in that, The scratch-resistant agent is prepared by the following method: 1) Disperse nano boron nitride and nano aluminum oxide in anhydrous ethanol, adjust the pH to 4.0-4.5 with hydrochloric acid, reflux and stir at 65-70℃ for 1-2 hours, filter, and dry to obtain hydroxylated nano boron nitride and hydroxylated nano aluminum oxide. 2) Hydroxylated boron nitride nanoparticles and hydroxylated alumina nanoparticles were dispersed in ethanol, ultrasonically dispersed, and 3-aminopropyltriethoxysilane and glacial acetic acid were added dropwise. The mixture was reacted at 60-65℃ for 5-6 hours, filtered, and washed to obtain aminated boron nitride nanoparticles and aminated alumina nanoparticles. 3) Disperse aminated boron nitride nanoparticles and aminated alumina nanoparticles in toluene, sonicate, add octamethylcyclotetrasiloxane and tetramethylammonium hydroxide, heat to 105-110℃, react under nitrogen protection for 6-8h, cool to room temperature, and centrifuge to obtain the product; 4) Mix the product with polyester-modified silicone to obtain a scratch-resistant agent.

4. The scratch-resistant and tough HIPS material according to claim 3, characterized in that, The raw materials used to prepare the scratch-resistant agent are as follows by weight: 40-50 parts of nano boron nitride 15-25 parts of nano-alumina 10-15 parts of aminopropyltriethoxysilane 1-2 parts glacial acetic acid 15-20 parts of octamethylcyclotetrasiloxane 0.2-0.5 parts of tetramethylammonium hydroxide 20-30 parts of polyester-modified silicone.

5. The scratch-resistant and tough HIPS material according to claim 1, characterized in that: The toughening agent is composed of methyl acrylate-butadiene-styrene copolymer and maleic anhydride-grafted SEBS in a weight ratio of (3-5):

1.

6. The scratch-resistant and tough HIPS material according to claim 1, characterized in that: The average particle size of the nano-boron nitride is 100-300 nm, and the average particle size of the nano-alumina is 400-800 nm.

7. The scratch-resistant and tough HIPS material according to claim 1, characterized in that: The polyether-polyamide block copolymer has the structural formula PA-b-PEG-b-PA and / or PA-b-PPG-b-PA.

8. The scratch-resistant and tough HIPS material according to claim 1, characterized in that: The styrene-butadiene rubber has a styrene content of 22.5-24.5% and a Mooney viscosity of 48-56.

9. The scratch-resistant and tough HIPS material according to claim 1, characterized in that: The melt flow rate of the polyethylene I at 190℃ / 2.16kg is 0.7g / 10min; The melt flow rate of the polyethylene II at 190℃ / 2.16kg is 2.6g / 10min; The melt flow rate of the polyethylene III at 190℃ / 2.16kg is 4.1g / 10min.

10. A method for preparing a scratch-resistant and tough HIPS material as described in any one of claims 1-9, characterized in that, The preparation steps include the following: S1. Mix dried high-impact polystyrene, polyethylene, styrene-butadiene rubber and polyether-polyamide block copolymer, then add scratch-resistant agent and toughening agent and mix to obtain a mixture; S2. The mixture is then placed in a twin-screw extruder, extruded, and granulated to obtain a scratch-resistant and tough HIPS material.

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