A bio-based polyamide resin composition, and a method of preparing and using the same
Patent Information
- Application Number
- CN202611043015.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-14
- Publication Date
- 2026-08-21
AI Technical Summary
但该方案仍存在明显缺陷：石化基阻燃剂的引入会大幅拉低产品整体生物基含量，多数产品生物基含量不足50%；卤系阻燃剂燃烧时释放有毒卤化氢及致癌多溴代副产物，无卤石化磷系阻燃剂易迁移析出，长期使用后阻燃性能衰减，且两类阻燃剂燃烧烟密度均较高，无法满足汽车内饰、电子电器领域的低烟低毒要求；同时阻燃剂与生物基聚酰胺界面相容性差，会显著降低材料抗冲击性能，难以兼顾力学性能与阻燃性能
本发明通过环氧官能化聚(3-羟基丁酸-co-4-羟基丁酸酯)弹性体、环氧化大豆油改性木质素磺酸钠与生物基植酸复配的全生物基阻燃增韧体系，仅需较低添加量即可实现超薄样条的最高等级无卤阻燃，燃烧过程无熔融滴落，烟密度显著降低，同时产品整体生物基占比保持在较高水平，有效解决了现有石化基阻燃剂改性方案生物基占比低、燃烧释放有毒烟气，以及单一生物质阻燃剂改性方案阻燃效率低、需极高添加量才能达到基本阻燃要求的缺陷。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of bio-based polyamide technology, and in particular to a bio-based polyamide resin composition, its preparation method and application. Background Technology
[0002] Bio-based polyamides are widely used in automotive interiors, electronic appliance housings and other fields due to their low carbon and environmental friendliness and excellent mechanical properties. With the implementation of the dual-carbon policy and the upgrading of low smoke and halogen-free fire protection requirements in various industries, the industry's demand for bio-based polyamide materials that combine high bio-based content, high flame retardancy and mechanical stability is becoming increasingly urgent.
[0003] Currently, mainstream bio-based flame-retardant polyamide technologies are mainly divided into two categories. The first category is the petrochemical-based flame retardant modification scheme. This involves adding petrochemical-derived flame retardants such as halogenated and organophosphorus flame retardants to the bio-based polyamide matrix. The flame retardant achieves its effect by capturing combustion free radicals through thermal decomposition and catalyzing char formation in the matrix. This scheme has mature technology and high flame retardant efficiency, and is the mainstream choice for current commercial products. However, this scheme still has significant drawbacks: the introduction of petrochemical-based flame retardants significantly reduces the overall bio-based content of the product, with most products having a bio-based content of less than 50%; halogenated flame retardants release toxic hydrogen halides and carcinogenic polybrominated byproducts during combustion, while halogen-free petrochemical phosphorus flame retardants are prone to migration and precipitation, resulting in a decline in flame retardant performance after long-term use. Furthermore, both types of flame retardants have high smoke densities, which cannot meet the low-smoke and low-toxicity requirements of automotive interiors and electronic appliances; at the same time, the poor interfacial compatibility between flame retardants and bio-based polyamides significantly reduces the material's impact resistance, making it difficult to balance mechanical properties and flame retardant properties.
[0004] The second category involves single-component biomass flame retardant modification schemes. These schemes use unmodified lignin, phytic acid, or other single components as flame retardants, relying on the char formation of biomass itself or acid catalysis to achieve flame retardancy. This approach offers good environmental friendliness. However, its flame retardant efficiency is extremely low, requiring the addition of more than 30 parts of flame retardant to achieve UL94 V-1 rating, which fails to meet the V-0 fire resistance requirement for a 1.6mm thickness. Furthermore, excessively high amounts of flame retardant can significantly reduce the material's mechanical properties, making it unsuitable for structural components. Unmodified biomass flame retardants also exhibit poor compatibility with polyamides, easily leading to agglomeration and resulting in large fluctuations in product performance and poor mass production stability. Currently, the industry urgently needs to address these technical shortcomings and develop bio-based polyamide materials that meet both environmental and performance requirements to satisfy the application needs of downstream sectors. Summary of the Invention
[0005] To address the shortcomings of existing bio-based polyamide modification technologies in simultaneously achieving high bio-based content, high-grade halogen-free flame retardancy, and stable mechanical properties, this invention provides a bio-based polyamide resin composition, its preparation method, and its application.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: A bio-based polyamide resin composition, by weight, comprises the following components: 100 parts of a bio-based polyamide matrix, which is obtained by mixing bio-based polyamide 56 and bio-based polyamide 11 at a mass ratio of 60-80:20-40; 5-12 parts of an epoxy-functionalized poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer, having an epoxy grafting rate of 1.2-2.5% and an elongation at break of not less than 800%; 8-18 parts of sodium lignosulfonate surface-treated with epoxidized soybean oil; 2-6 parts of bio-based phytic acid; and 0.2-1 parts of a processing aid, which is composed of an antioxidant and a lubricant, wherein the antioxidant is selected from at least one of antioxidant 1010 and antioxidant 168, and the lubricant is selected from at least one of calcium stearate and ethylene bis-stearamide.
[0007] Furthermore, the epoxy-functionalized poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer is prepared by the following method: poly(3-hydroxybutyrate-co-4-hydroxybutyrate), glycidyl methacrylate and dicumyl peroxide are melt-grafted in a twin-screw extruder at a grafting temperature of 160~180℃ and a screw speed of 100~150rpm.
[0008] Furthermore, the sodium lignosulfonate surface-treated with epoxidized soybean oil is prepared by the following steps: dispersing sodium lignosulfonate in anhydrous ethanol to prepare a dispersion system with a solid content of 15-25%; adding epoxidized soybean oil accounting for 3-8% of the mass of sodium lignosulfonate; heating to 60-75℃ and stirring at 200-300 rpm for 2-4 hours; separating the solid product by vacuum filtration; and drying the solid product under vacuum at 60-70℃ for 6-8 hours to obtain the final product.
[0009] Furthermore, the 1.6mm thick standard test specimen of the composition achieves a UL94 V-0 flame retardant rating, exhibits no melting or dripping during combustion, and has a smoke density that is more than 40% lower than that of bio-based polyamide without added flame retardant components; the tensile strength of the composition is not less than 45MPa, and the notched impact strength is not less than 8kJ / m. 2 .
[0010] Furthermore, in accordance with the ASTM D6866-24 standard, "Determination of bio-based content in samples by radiocarbon dating," this indicator is defined as the percentage of bio-based carbon in the total organic carbon of a sample, and the bio-based content of this composition is not less than 80%.
[0011] Furthermore, the following steps are included: S1. Dry each component until the moisture content is no higher than 500 ppm; S2. Add all the dried components to a high-speed mixer and mix at 300-500 rpm for 5-10 minutes to obtain a premix. S3. The premixed material is added to a twin-screw extruder, and after melt extrusion, cooling, and pelletizing, the bio-based polyamide resin composition is obtained. The operating temperature of each section of the twin-screw extruder is 230~260℃, the screw speed is 200~350rpm, the length-to-diameter ratio is 40~48:1, and the vacuum degree during extrusion is not higher than -0.06MPa.
[0012] Furthermore, in step S1, the bio-based polyamide matrix is dried in a forced-air dryer at 80~100℃ for 8~12h, and the remaining components are dried in a vacuum dryer at 60~70℃ for 4~6h; in step S3, the temperatures of each section of the twin-screw extruder from the feeding section to the die head are set sequentially to 230℃, 240℃, 250℃, 255℃, 260℃, 255℃, 250℃, and 245℃, wherein the die head temperature is lower than the melting section temperature to enhance melt strength, prevent strip breakage, and prevent the accumulation of high-temperature degradation products.
[0013] Furthermore, the composition is injection molded to prepare automotive interior parts or electronic appliance housings; during the injection molding process, the barrel temperature is 240~270℃ and the mold temperature is 60~90℃.
[0014] Furthermore, during the injection molding process, the injection pressure is 80~120MPa, the injection speed is 30~50mm / s, the holding pressure is 40~60MPa, the holding time is 10~20s, and the cooling time is 15~30s; the resulting product is tested according to VDA 270 standard and the odor level is ≤3.
[0015] Furthermore, the tensile strength retention rate of the obtained product is ≥85% after heat aging at 150℃ for 1000h, and ≥80% after aging at 85℃ / 85% relative humidity for 1000h.
[0016] The present invention has the following beneficial effects: This invention utilizes an epoxy-functionalized poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer, epoxidized soybean oil-modified sodium lignin sulfonate, and bio-based phytic acid to create a fully bio-based flame-retardant and toughening system. This system achieves the highest level of halogen-free flame retardancy in ultrathin samples with only a low addition amount. During combustion, there is no melting or dripping, and the smoke density is significantly reduced. At the same time, the overall bio-based content of the product remains at a high level. This effectively solves the shortcomings of existing petrochemical-based flame retardant modification schemes, such as low bio-based content and release of toxic fumes during combustion, as well as single biomass flame retardant modification schemes, which have low flame retardant efficiency and require extremely high addition amounts to meet basic flame retardant requirements.
[0017] This invention introduces epoxy reactive functional groups on the surface of elastomers and sodium lignosulfonate, which can undergo interfacial bonding reactions with the active end groups of the bio-based polyamide matrix, effectively improving the interfacial bonding strength between each functional phase and the matrix. While meeting flame retardant requirements, it maintains the material's excellent rigidity and impact resistance, effectively solving the defects of existing technologies such as significant attenuation of mechanical properties and poor batch stability of product performance caused by poor compatibility between flame retardants and the matrix.
[0018] The fully bio-based functional components used in this invention are free of easily migrating small molecules. The preparation process fully removes residual volatile components through gradient temperature control and vacuum devolatilization, resulting in products with excellent odor levels. The mechanical properties retained after thermo-oxidative aging and damp-heat aging meet the requirements of downstream applications. It can be directly adapted to existing extrusion and injection molding processes without the need for additional dedicated production equipment. It is suitable for fields with high requirements for environmental protection, flame retardancy, and long-term stability, such as automotive interiors and electronic appliance housings, and has good industry promotion value. Attached Figure Description
[0019] Figure 1 This is a flowchart illustrating the preparation process of a bio-based polyamide resin composition proposed in this invention. Figure 2 This is a bar chart showing the comparison of core performance of different samples proposed in this invention. Figure 3 Radar charts showing the comprehensive performance of different samples proposed in this invention; Figure 4 This is a bi-Y-axis line graph showing the relationship between the amount of modified lignin added and the performance proposed in this invention. Detailed Implementation
[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0021] Preparation of epoxy-functionalized poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer Preparation of the elastomer used in Example 1: 100 parts of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a number average molecular weight of 80,000 and a 4HB molar ratio of 10 mol% were taken, 2 parts of glycidyl methacrylate and 0.1 parts of dicumyl peroxide were added, and the mixture was fed into a twin-screw extruder for melt grafting. The grafting temperature was set at 160°C and the screw speed was 100 rpm. The resulting product had an epoxy grafting rate of 1.2% and an elongation at break of 820%.
[0022] Preparation of the elastomer used in Example 2: 100 parts of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a number average molecular weight of 120,000 and a 4HB molar ratio of 30 mol% were taken, 5 parts of glycidyl methacrylate and 0.3 parts of dicumyl peroxide were added, and the mixture was fed into a twin-screw extruder for melt grafting. The grafting temperature was set at 180°C and the screw speed was 150 rpm. The resulting product had an epoxy grafting rate of 2.5% and an elongation at break of 910%.
[0023] Preparation of the elastomer used in Example 3: 100 parts of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with a number average molecular weight of 100,000 and a 4HB molar ratio of 20 mol% were taken, and 3.5 parts of glycidyl methacrylate and 0.2 parts of dicumyl peroxide were added. The mixture was fed into a twin-screw extruder for melt grafting. The grafting temperature was set at 170°C and the screw speed was 125 rpm. The resulting product had an epoxy grafting rate of 1.9% and an elongation at break of 870%.
[0024] The three epoxy-functionalized elastomer products were analyzed by 1H NMR spectroscopy, and the characteristic peaks of epoxy groups appeared at chemical shifts δ=3.1~3.3ppm, confirming that the grafting reaction was effective. Gel permeation chromatography determined that the number-average molecular weights of the elastomers corresponding to Examples 1, 2, and 3 were 79,600, 119,800, and 99,700, respectively, and their molecular weight distribution indices (PDI) were 1.6, 1.9, and 1.7, respectively. No significant degradation occurred during the reaction process. The epoxy functional groups introduced onto the surface of the above elastomers can undergo interfacial bonding reactions with the terminal amino groups of the bio-based polyamides, thus overcoming the defect of poor interfacial compatibility between the flame-retardant functional phase and the matrix.
[0025] Preparation of sodium lignin sulfonate from soybean oil surface treatment after epoxidation Preparation of treated lignin in Example 1: Sodium lignin sulfonate was dispersed in anhydrous ethanol to prepare a dispersion system with a solid content of 15%. Epoxidized soybean oil accounting for 3% of the mass of sodium lignin sulfonate was added. The mixture was heated to 60°C and stirred at 200 rpm for 2 hours. The solid product was separated by filtration and dried under vacuum at 60°C for 6 hours to obtain the final product.
[0026] Preparation of treated lignin in Example 2: Sodium lignin sulfonate was dispersed in anhydrous ethanol to prepare a dispersion system with a solid content of 25%. Epoxidized soybean oil accounting for 8% of the mass of sodium lignin sulfonate was added. The mixture was heated to 75°C and stirred at 300 rpm for 4 hours. The solid product was separated by filtration and dried under vacuum at 70°C for 8 hours to obtain the final product.
[0027] Preparation of treated lignin in Example 3: Sodium lignin sulfonate was dispersed in anhydrous ethanol to prepare a dispersion system with a solid content of 20%. Epoxidized soybean oil accounting for 5.5% of the mass of sodium lignin sulfonate was added. The mixture was heated to 67°C and stirred at 250 rpm for 3 hours. The solid product was separated by filtration and dried under vacuum at 65°C for 7 hours to obtain the final product.
[0028] The above-mentioned processing technology reduces the surface polarity of sodium lignosulfonate, reduces particle agglomeration, and solves the defect of poor dispersibility of unmodified biomass flame retardants.
[0029] Composition Formulation and Preparation The bio-based carbon content of each component used in this embodiment is as follows: approximately 100% bio-based polyamide 56 / polyamide 11, approximately 100% sodium lignosulfonate, approximately 98% phytic acid, approximately 85% epoxidized soybean oil, and approximately 95% poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer. The total bio-based carbon content of all formulations is calculated to be no less than 80% as required.
[0030] Example 1
[0031] The components are as follows by weight: 100 parts of bio-based polyamide matrix, wherein the mass ratio of bio-based polyamide 56 to bio-based polyamide 11 is 60:40; 5 parts of epoxy functionalized elastomer prepared in Example 1 above; 8 parts of prepared treated sodium lignosulfonate; 2 parts of bio-based phytic acid; and 0.3 parts of processing aids, wherein antioxidant 1010 is 0.2 parts and calcium stearate is 0.1 parts.
[0032] Preparation steps: S1 The bio-based polyamide matrix was dried at 80°C for 8 hours by forced air drying, and the remaining components were dried at 60°C under vacuum for 4 hours. The moisture content of all components was controlled at 420 ppm. S2 adds all the dried components to a high-speed mixer and mixes them at 300 rpm for 5 minutes to obtain a premix. S3 adds the premixed material to a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperatures of each section from the feeding section to the die head are set sequentially to 230℃, 240℃, 250℃, 255℃, 260℃, 255℃, 250℃, and 245℃. The die head temperature is lower than the highest temperature of the melting section to enhance melt strength, prevent strip breakage, and avoid the accumulation of high-temperature degradation products. The screw speed is 200 rpm, and the vacuum degree during extrusion is -0.07 MPa. After melt extrusion, cooling, and pelletizing, a bio-based polyamide resin composition is obtained.
[0033] During extrusion, phytic acid undergoes in-situ thermal decomposition within the 230-260℃ range, transforming into small-molecule phosphoric acids such as pyrophosphate and orthophosphate, which serve as the active acid source for catalytic char formation. Sodium lignin sulfonate decomposes, releasing sulfonic acid groups and phenolic hydroxyl groups, acting as a partial acid source. Phytic acid decomposition products serve as a secondary acid source, while the amide groups in bio-based polyamide act as a nitrogen source. Lignin serves as a natural char source. These three components form a three-in-one expansion flame-retardant system, improving flame-retardant efficiency and overcoming the low efficiency of single biomass flame retardants. The dispersion and toughening mechanism involves: epoxidized soybean oil treatment reducing the surface polarity of sodium lignin sulfonate; the epoxy groups react with the terminal amino groups of the polyamide for compatibilization; and the poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer synergistically absorbs impact energy. In this embodiment, the measured notched impact strength is 11.2 kJ / m. 2 .
[0034] Example 2
[0035] Example 2: Components by weight: 100 parts of bio-based polyamide matrix, wherein the mass ratio of bio-based polyamide 56 to bio-based polyamide 11 is 80:20; The above Example 2 contains 12 parts of epoxy-functionalized elastomer, 18 parts of treated sodium lignosulfonate, 6 parts of bio-based phytic acid, and 1 part of processing aid, of which antioxidant 168 is 0.4 parts and ethylene bis-stearamide is 0.6 parts.
[0036] Preparation steps: S1 The bio-based polyamide matrix was dried at 100℃ for 12 hours by forced air drying, and the remaining components were dried at 70℃ under vacuum for 6 hours. The moisture content of all components was controlled at 380 ppm. S2 adds all the dried components to a high-speed mixer and mixes them at 500 rpm for 10 minutes to obtain a premix. S3 adds the premixed material to a twin-screw extruder with a length-to-diameter ratio of 48:1. The temperatures of each section from the feed section to the die head are set sequentially to 230℃, 240℃, 250℃, 255℃, 260℃, 255℃, 250℃, and 245℃. The die head temperature is lower than the highest temperature of the melting section to enhance melt strength, prevent strip breakage, and avoid the accumulation of high-temperature degradation products. The screw speed is 350 rpm, and the vacuum degree during extrusion is -0.08 MPa. After melt extrusion, cooling, and pelletizing, a bio-based polyamide resin composition is obtained. The measured notched impact strength in this embodiment is 8.3 kJ / m. 2 .
[0037] Example 3
[0038] Example 3: Components by weight: 100 parts of bio-based polyamide matrix, wherein the mass ratio of bio-based polyamide 56 to bio-based polyamide 11 is 70:30; The above Example 3 contains 8.5 parts of epoxy-functionalized elastomer, 12 parts of treated sodium lignosulfonate, 4 parts of bio-based phytic acid, and 0.6 parts of processing aids, including 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, and 0.2 parts of calcium stearate.
[0039] Preparation steps: S1 The bio-based polyamide matrix was dried at 90°C for 10 hours by forced air drying, and the remaining components were dried at 65°C under vacuum for 5 hours. The moisture content of all components was controlled at 400 ppm. S2 adds all the dried components into a high-speed mixer and mixes them at 400 rpm for 7.5 minutes to obtain a premix. S3 adds the premixed material to a twin-screw extruder with a length-to-diameter ratio of 44:1. The temperatures of each section from the feed section to the die head are set sequentially to 230℃, 240℃, 250℃, 255℃, 260℃, 255℃, 250℃, and 245℃. The die head temperature is lower than the highest temperature of the melting section to enhance melt strength, prevent strip breakage, and avoid the accumulation of high-temperature degradation products. The screw speed is 275 rpm, and the vacuum degree during extrusion is -0.07 MPa. After melt extrusion, cooling, and pelletizing, a bio-based polyamide resin composition is obtained. The measured notched impact strength in this embodiment is 9.7 kJ / m. 2 .
[0040] Comparative Example 1: An existing petrochemical-based flame retardant modification scheme, comprising the following components by weight: 100 parts of bio-based polyamide matrix, wherein the mass ratio of bio-based polyamide 56 to bio-based polyamide 11 is 70:30; 12 parts of petrochemical-based red phosphorus masterbatch; and 0.6 parts of processing aids, including 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, and 0.2 parts of calcium stearate. The preparation steps are the same as in Example 3.
[0041] Comparative Example 2: An existing single biomass flame retardant modification scheme, comprising the following components by weight: 100 parts of bio-based polyamide matrix, wherein the mass ratio of bio-based polyamide 56 to bio-based polyamide 11 is 70:30; 28 parts of unmodified lignin; and 0.6 parts of processing aids, including 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, and 0.2 parts of calcium stearate. The preparation steps are the same as in Example 3.
[0042] Comparative Example 2 uses the principle of equal addition of flame retardant components. 28 parts of unmodified lignin, which are equivalent to the median value of 10-24 parts of sodium lignosulfonate + phytic acid in Examples 1, 2 and 3, are selected as flame retardants to eliminate the interference of the difference in addition amount on the comparison of flame retardant effects.
[0043] Because lignin itself has a brown base color, this composition is suitable for the production of dark-colored parts; the hygroscopicity of the polyamide matrix can be solved by fully drying before processing, or by adding 0.1 to 0.3 parts of polycarbodiimide moisture scavenger during the premixing stage, without affecting the performance of the product.
[0044] Performance test data table and description Table 1. Basic performance parameters of the examples and comparative examples
[0045] The blank matrix was pure bio-based polyamide with a PA56 / PA11 mass ratio of 70:30. Under the same test conditions, the specific extinction area (SEA) was 1280 μm. 2 / kg, the reduction rate of smoke density is calculated based on the blank matrix.
[0046] Table 1 Explanation: Data shows that all three examples meet the UL94 V-0 halogen-free flame retardant requirements, with a bio-based carbon content of over 80%, and a smoke density that is more than 40% lower than that of the same matrix bio-based polyamide without added flame retardant components. The mechanical properties retention rate is close to that of the pure matrix. Comparative Example 1 has a bio-based content of less than 50%, poor smoke density reduction effect, and significant mechanical property degradation. Comparative Example 2 can only achieve V-1 flame retardancy, with severe mechanical property degradation. This verifies the effectiveness of this invention in solving the three core defects of the prior art.
[0047] Table 2 Aging and environmental performance parameters of the examples and comparative examples
[0048] Table 2 explains: The data shows that the tensile strength retention rate under thermal aging and damp heat aging in the three examples is higher than 80%, the VOC emission is lower than the requirements of the automotive interior industry standard, and the odor level is ≤3. Comparative Example 1 has poor aging performance and high VOC emission, and Comparative Example 2 has aging performance far lower than the examples. This verifies that the long-term stability and environmental protection of the material of the present invention are superior to the existing technical solutions.
[0049] refer to Figure 2This figure visually presents the differences in core performance among different samples. All three examples meet the UL94 V-0 flame retardant requirements corresponding to quantification value 3. The tensile strength and notched impact strength show only a slight decrease compared to the blank matrix, which are far higher than the mechanical properties of the two comparative examples. The smoke density reduction rate exceeds 40%, which is far better than the 12% of comparative example 1 and the 27% of comparative example 2. The data in this figure verifies that the three-source integrated intumescent flame retardant system constructed in this invention has the advantages of high flame retardant efficiency, low mechanical property loss, and low smoke release. At the same time, the bio-based content of the examples is higher than 80%, which solves the core defects of existing petrochemical-based flame retardant modification schemes, such as low bio-based content and high smoke toxicity, and single biomass flame retardant modification schemes, such as insufficient flame retardant efficiency and severe mechanical property degradation. The performance balance is better than the existing technology.
[0050] refer to Figure 3 This figure visually presents the differences in the overall performance of different samples. The radar map coverage area of Example 3 is much larger than that of the two comparative examples, and only slightly smaller than that of the blank matrix, indicating its excellent overall performance balance. The thermal aging and damp heat aging retention rates of the example are both higher than 80%, far superior to the aging performance of the two comparative examples. The VOC emission is far below the limits required by the automotive interior industry, the bio-based content meets the requirements for low-carbon materials, and the odor level meets the standards for use in vehicles. This figure verifies that the interface compatibilization design of this invention effectively improves the bonding strength between the functional phase and the matrix, solves the defects of poor long-term stability and insufficient environmental protection of existing modification schemes, and is suitable for the stringent use requirements in the fields of automotive interiors and electronic appliances.
[0051] refer to Figure 4 This figure visually illustrates the influence of modified lignin addition on the two core properties. With increasing modified lignin addition, the smoke density reduction rate shows a linear upward trend, indicating that the synergistic flame-retardant effect of lignin as a char source and phytic acid source gradually strengthens with increasing addition. Meanwhile, the notched impact strength only shows a gradual downward trend, consistently remaining at 8 kJ / m². 2 The above structural components meet the usage requirements. This figure verifies the synergistic toughening scheme of epoxidized soybean oil surface treatment and epoxy functionalized elastomer adopted in this invention, which effectively alleviates the mechanical property degradation problem caused by increasing the amount of flame retardant added. It solves the defect of the sharp drop in mechanical properties under high addition of existing biomass flame retardants, and the flame retardant addition ratio can be flexibly adjusted according to the performance requirements of different application scenarios, making it more adaptable.
[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A bio-based polyamide resin composition, characterized in that, The product comprises, by weight, the following components: 100 parts of a bio-based polyamide matrix, which is obtained by mixing bio-based polyamide 56 and bio-based polyamide 11 at a mass ratio of 60-80:20-40; 5-12 parts of an epoxy-functionalized poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer with an epoxy grafting rate of 1.2-2.5% and an elongation at break of not less than 800%; 8-18 parts of sodium lignosulfonate treated with epoxidized soybean oil; 2-6 parts of bio-based phytic acid; and 0.2-1 parts of a processing aid, which is composed of an antioxidant and a lubricant, wherein the antioxidant is selected from at least one of antioxidant 1010 and antioxidant 168, and the lubricant is selected from at least one of calcium stearate and ethylene bis-stearamide.
2. The bio-based polyamide resin composition according to claim 1, characterized in that, The epoxy-functionalized poly(3-hydroxybutyrate-co-4-hydroxybutyrate) elastomer is prepared by the following method: poly(3-hydroxybutyrate-co-4-hydroxybutyrate), glycidyl methacrylate and dicumyl peroxide are melt-grafted in a twin-screw extruder at a grafting temperature of 160~180℃ and a screw speed of 100~150rpm.
3. The bio-based polyamide resin composition according to claim 1, characterized in that, The sodium lignosulfonate surface-treated with epoxidized soybean oil is prepared by the following steps: dispersing sodium lignosulfonate in anhydrous ethanol to prepare a dispersion system with a solid content of 15-25%; adding epoxidized soybean oil at a mass of 3-8% of sodium lignosulfonate; heating to 60-75℃ and stirring at 200-300 rpm for 2-4 hours; and separating the solid product by vacuum filtration. The solid product is dried under vacuum at 60-70℃ for 6-8 hours to obtain the product.
4. The bio-based polyamide resin composition according to claim 1, characterized in that, The composition achieves a UL94 V-0 flame retardant rating on a 1.6mm thick standard test specimen, exhibits no melting or dripping during combustion, and has a smoke density that is more than 40% lower than that of bio-based polyamide without added flame retardant components. The composition also possesses a tensile strength of not less than 45MPa and a notched impact strength of not less than 8kJ / m². 2 .
5. The bio-based polyamide resin composition according to claim 1, characterized in that, The bio-based content of the composition is determined according to ASTM D6866-24 standard as the percentage of bio-based carbon in total organic carbon, and is not less than 80%.
6. A method for preparing a bio-based polyamide resin composition, used to prepare the bio-based polyamide resin composition according to any one of claims 1 to 5, characterized in that, The steps include the following: S1. Dry each component until the moisture content is no higher than 500 ppm; S2. Add all the dried components to a high-speed mixer and mix at 300-500 rpm for 5-10 minutes to obtain a premix. S3. The premixed material is added to a twin-screw extruder, and after melt extrusion, cooling, and pelletizing, the bio-based polyamide resin composition is obtained. The operating temperature of each section of the twin-screw extruder is 230~260℃, the screw speed is 200~350rpm, the length-to-diameter ratio is 40~48:1, and the vacuum degree during extrusion is not higher than -0.06MPa.
7. The preparation method according to claim 6, characterized in that, In step S1, the bio-based polyamide matrix is dried in a forced-air dryer at 80~100℃ for 8~12h, and the remaining components are dried in a vacuum dryer at 60~70℃ for 4~6h. In step S3, the temperatures of each section of the twin-screw extruder from the feeding section to the die head are set sequentially to 230℃, 240℃, 250℃, 255℃, 260℃, 255℃, 250℃, and 245℃, wherein the die head temperature is lower than the melting section temperature.
8. The use of a bio-based polyamide resin composition for use with the bio-based polyamide resin composition as described in any one of claims 1 to 5, characterized in that, The composition is injection molded to prepare automotive interior parts or electronic appliance housings; the barrel temperature during injection molding is 240~270℃, and the mold temperature is 60~90℃.
9. The application according to claim 8, characterized in that, During injection molding, the injection pressure is 80~120MPa, the injection speed is 30~50mm / s, the holding pressure is 40~60MPa, the holding time is 10~20s, and the cooling time is 15~30s; the resulting product has an odor level of ≤3 according to VDA 270 standard testing.
10. The application according to claim 8, characterized in that, The tensile strength retention rate of the obtained product is ≥85% after heat aging at 150℃ for 1000h, and ≥80% after aging at 85℃ / 85% relative humidity for 1000h.