A bio-based injection molding compound and process for its production

Abstract

This invention relates to the field of bio-based injection molding technology, specifically to a bio-based injection molding compound and its production process, comprising the following raw materials in parts by weight: 80-95 parts matrix resin, 4-6 parts modified reinforcing components, 2-3 parts bio-based crosslinking components, and 2.5 parts bio-based functional additives. The matrix resin is based on polylactic acid (PLA), compounded with polybutylene furanate and polyhydroxyalkanoates to form a ternary bio-based polyester system. This system compensates for the brittleness of PLA at the matrix level, improving elongation at break. The addition of modified reinforcing components enhances the material's rigidity and heat resistance through nanoscale reinforcement. Furthermore, the ionic liquid modification improves the compatibility with the matrix interface, preventing the mechanical properties from decreasing due to reinforcing phase agglomeration. Nanocellulose replaces traditional glass fiber reinforcement, avoiding wear on the screw and mold, and extending equipment lifespan.

Description

Technical Field

[0001] This invention relates to the field of bio-based injection molding technology, specifically to a bio-based injection molding compound and its manufacturing process. Background Technology

[0002] With the deepening of global "dual carbon" initiatives and increasingly stringent regulations on plastic pollution control, the white pollution problem caused by traditional petrochemical-based plastics, which rely on non-renewable petroleum resources and whose products are difficult to degrade naturally, has become a core bottleneck restricting the sustainable development of the polymer materials industry. Against this backdrop, bio-based injection molding plastics, as a thermoplastic injection molding material prepared from renewable biomass such as corn, cassava, and straw through biosynthesis or chemical modification, have become an ideal alternative to petrochemical-based injection molding plastics due to their core advantages of renewable raw materials, high bio-based content, and compostable and biodegradable products. Bio-based injection molding plastics use bio-based polyesters such as polylactic acid and polyhydroxyalkanoates as the core matrix and can be molded into various products such as food packaging, electronic and electrical appliance casings, automotive interiors, and household goods through injection molding processes.

[0003] Pure polylactic acid resin is a typical brittle polymer material with low elongation at break and low notched impact strength. It cracks easily under slight external force. In order to improve the brittleness of pure polylactic acid, it is often modified by compounding a small amount of bio-based toughening polyester. However, there is a common problem of imbalance between toughening and rigidity and heat resistance. After toughening, the tensile strength, flexural strength and other rigidity indicators of the material decrease significantly. Based on this, the present invention provides a bio-based injection molding compound and its production process. Summary of the Invention

[0004] The purpose of this invention is to provide a bio-based injection molding compound and its production process. The bio-based injection molding compound prepared by this invention and its production process have excellent comprehensive performance, and the production process is stable and controllable, making it suitable for industrial mass production requirements.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a bio-based injection molding compound and its production process, comprising the following raw materials in parts by weight: 80-95 parts matrix resin component, 4-6 parts modified reinforcing component, 2-3 parts bio-based crosslinking component, and 2.5 parts bio-based functional additive component; The preparation steps of the bio-based injection molding compound and its manufacturing process are as follows: S1. Raw material pretreatment: Vacuum dry each raw material of the matrix resin component, pre-prepare the modified reinforcing component, activate the bio-based crosslinking component, and pre-mix and homogenize the bio-based functional additive component. S2. Raw material premixing: The dried matrix resin component is added to a high-speed mixer and mixed at high speed. Then, the modified reinforcing component, the activated bio-based crosslinking component and the bio-based functional additive component are added and mixed at low speed. The material temperature is controlled during the mixing process. After mixing, the material is sieved to obtain the premix. S3. Twin-screw extrusion granulation: The premixed material is added to a parallel twin-screw extruder, and after segmented temperature control, three-stage vacuum devolatilization, melt mixing and cross-linking, it is extruded into strips. After the strips are cooled, they are granulated, and the particles are dried in a fluidized bed to obtain bio-based injection molding particles. S4. Pre-injection drying: Vacuum dry the bio-based injection molding particles again to remove trace amounts of moisture adsorbed during storage; S5. Injection Molding: The dried particles are added to a screw injection molding machine, melted in the barrel, injected into the mold, held under pressure and cooled before demolding to obtain the bio-based injection molded plastic product.

[0006] Furthermore, the matrix resin component is composed of polylactic acid, polybutylene furanate, and polyhydroxyalkanoate, wherein the mass ratio of polylactic acid, polybutylene furanate, and polyhydroxyalkanoate is 24:8:5.

[0007] Furthermore, the preparation method of the matrix resin component is as follows: polylactic acid, polybutylene furanate, and polyhydroxy fatty acid ester are placed in a vacuum oven for independent drying. After drying, each raw material is cooled to room temperature, sealed and stored to obtain the matrix resin component.

[0008] Furthermore, the modified reinforcing component is composed of modified nanocellulose.

[0009] Furthermore, the preparation method of the modified reinforcing component is as follows: using modified nanocellulose prepared from agricultural waste as a base, adding nanocellulose aqueous dispersion and 1-butyl-3-methylimidazolium acetate ionic liquid and stirring, followed by spray drying treatment to obtain the modified reinforcing component.

[0010] Furthermore, the bio-based crosslinking component is composed of cashew phenol glycidyl ether-maleic anhydride copolymer.

[0011] Furthermore, the preparation method of the bio-based crosslinking component is as follows: take cashew phenol glycidyl ether-maleic anhydride copolymer, add dibutyltin dilaurate crosslinking catalyst, mix and preheat, and stir slightly during the process to ensure uniform mixing. After preheating, quickly cool to room temperature, seal and store, and obtain the bio-based crosslinking component after activation treatment.

[0012] Furthermore, the bio-based functional additive component is composed of a bio-based compound antioxidant, a bio-based lubricant, and a bio-based nucleating agent, wherein the mass ratio of the bio-based compound antioxidant, the bio-based lubricant, and the bio-based nucleating agent is 0.8:0.7:1.

[0013] Furthermore, the preparation method of the bio-based functional additive component is as follows: bio-based compound antioxidant, bio-based lubricant and bio-based nucleating agent are put into a small mixer, stirred and mixed, and then sieved to remove agglomerated materials to obtain a homogeneous bio-based functional additive component.

[0014] Furthermore, the bio-based compound antioxidant is a mixture of vitamin E and rosemary extract in a mass ratio of 1:1, the bio-based lubricant is erucamide, and the bio-based nucleating agent is polylactic acid oligomer grafted starch.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, the matrix resin component is polylactic acid as the core, compounded with polybutylene furanate and polyhydroxyalkanoate to form a ternary bio-based polyester system. This system compensates for the brittleness of polylactic acid at the matrix level and improves the elongation at break. By adding modified reinforcing components, the rigidity and heat resistance of the material are improved through nanoscale reinforcement. Furthermore, the compatibility between the ionic liquid and the matrix interface is improved after modification, avoiding the decrease in mechanical properties caused by the agglomeration of the reinforcing phase. The bio-based crosslinking components construct a three-dimensional network structure through dynamic crosslinking, further strengthening the interfacial bonding force between the components and improving the cohesive energy of the material. The three factors work synergistically to enable the bio-based injection molding compound to maintain high rigidity while achieving high toughness.

[0016] 2. In this invention, the matrix resin component undergoes a dedicated vacuum drying pretreatment to prevent hydrolysis and degradation during processing from the source. The dynamic cross-linking characteristics of the bio-based cross-linking component achieve a balance between processing flowability and product heat resistance. The bio-based functional additives specifically address processing pain points, with compounded antioxidants preventing high-temperature thermo-oxidative degradation, lubricants reducing processing torque and mold sticking risk, and nucleating agents accelerating crystallization and improving product dimensional stability. The modified reinforcing component is nanocellulose, which replaces traditional glass fiber reinforcement, avoiding wear on the screw and mold and extending the service life of the equipment.

[0017] 3. In this invention, all components are bio-based or bio-based modified materials, without petrochemical-based matrix resins or core functional components, and all components are free of heavy metals and toxic additives, meeting the national standards for food contact plastics. The ionic liquid nanocellulose of the modified reinforcing component is prepared from agricultural waste, and the bio-based crosslinking components and functional additives are mostly natural plant oil derivatives or microbial synthetic products, with readily available and inexpensive raw materials. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0020] Example 1: A bio-based injection molding compound and its production process, comprising the following raw materials in parts by weight: 80 parts matrix resin component, 4 parts modified reinforcing component, 2 parts bio-based crosslinking component, and 2.5 parts bio-based functional additive component. The preparation steps of bio-based injection molding compounds and their manufacturing process are as follows: S1. Raw material pretreatment: Vacuum dry each raw material of the matrix resin component to a moisture content ≤0.05%, pre-preparation of modified reinforcing components is completed, bio-based crosslinking components are activated, and bio-based functional additive components are pre-mixed and homogenized. S2. Raw material premixing: Add the dried matrix resin component to a high-speed mixer and mix at 1200 rpm for 3 minutes. Then add the modified reinforcing component, the activated bio-based crosslinking component and the bio-based functional additive component and mix at 800 rpm for 5 minutes for low-speed mixing. During the mixing process, control the material temperature to ≤45℃. After mixing, sieve through a 60-mesh sieve to obtain the premix. S3. Twin-screw extrusion granulation: The premixed material is added to a parallel twin-screw extruder with an L / D ratio of 40. The temperature is controlled in stages, with a range of 140 to 185°C. Three-stage vacuum devolatilization is performed with a vacuum degree of -0.085 to -0.095 MPa. After melt mixing and crosslinking, the material is extruded into strips. The strips are cooled in a 25°C water bath and then granulated. The granules are dried in a fluidized bed at 60°C for 4 hours until the moisture content is ≤0.03%, thus obtaining bio-based injection molding granules. S4. Pre-injection molding drying: The bio-based injection molding particles are vacuum dried again at 80℃ / 4h to remove trace amounts of moisture adsorbed during storage. The moisture content of the particles after drying is ≤0.03%. S5. Injection molding: The dried particles are added to a screw injection molding machine, melted in the barrel at 170-185°C, injected into the mold at 40-60°C, and demolded after holding pressure and cooling to obtain the bio-based injection molded product.

[0021] The matrix resin component consists of polylactic acid (PLA), polybutylene furanate (PBF), and polyhydroxyalkanoates (PHA), with a mass ratio of 24:8:5. The preparation method is as follows: PLA, PBF, and PHA are individually dried in a vacuum oven. The drying parameters for PLA are 85℃ / 8h and -0.09MPa, for PBF 75℃ / 6h and -0.09MPa, and for PHA 60℃ / 12h and -0.08MPa. After drying, each raw material is cooled to room temperature (≤25℃), sealed, and stored, yielding a product with a moisture content ≤0.05%. The matrix resin components include polylactic acid (PLA), a resin with a weight-average molecular weight of 120,000 and a D-type content of 4.5%. It has a linear polymer structure with high molecular chain regularity. Polybutylene furanate has an elongation at break of ≥300% and a glass transition temperature Tg=35℃. Its molecular chain contains a furan ring structure, combining the biodegradability of aliphatic polyesters with the high toughness and high heat resistance of aromatic polyesters. It has excellent thermoplastic processing performance and good compatibility with PLA. Polyhydroxy fatty acid ester is a microbially synthesized polyester, belonging to intracellular polymers. Its molecular chain is an oligomer of aliphatic hydroxy fatty acids, with strong structural flexibility, excellent low-temperature toughness, and degradation performance that can be regulated by microorganisms.

[0022] The modified reinforcing component is composed of modified nanocellulose. The preparation method of the modified reinforcing component is as follows: using nanocellulose prepared from agricultural waste as a base, a 2% concentration of nanocellulose aqueous dispersion is prepared, and 1-butyl-3-methylimidazolium acetate ionic liquid is added at 1.2% of the dispersion mass. The mixture is stirred in a constant temperature water bath at 60℃ and 300 rpm for 2 hours, and then ultrasonically dispersed at 300W power and 20kHz frequency for 30 minutes. Subsequently, it is spray-dried with an inlet air temperature of 160℃, an outlet air temperature of 80℃, and a feed rate of 5mL / min to obtain white modified nanocellulose powder. The powder has a bulk density of 0.32g / cm³ and a moisture content of ≤0.04%. The modified reinforcing component is prepared by weighing according to the weight parts. The modified nanocellulose is prepared by surface chemical modification with ionic liquid based on natural nanocellulose, and has both the high specific surface area enhancement characteristics of nanomaterials and the interface modification characteristics of ionic liquids.

[0023] The bio-based crosslinking component is composed of cashew phenol glycidyl ether-maleic anhydride copolymer. The preparation method of the bio-based crosslinking component is as follows: weigh a portion of cashew phenol glycidyl ether-maleic anhydride copolymer, add 0.1% of its mass of dibutyltin dilaurate crosslinking catalyst, mix, and place in a forced-air drying oven to preheat at 100℃ for 15 min, stirring slightly during the process to ensure uniform mixing. After preheating, quickly cool to room temperature ≤25℃, seal and store, and obtain the bio-based crosslinking component after activation treatment. The cashew phenol glycidyl ether-maleic anhydride copolymer is a functional copolymer made by grafting glycidyl ether and maleic anhydride with natural cashew phenol as the core raw material. The molecular chain contains active groups such as epoxy groups and maleic anhydride groups, and has dynamic reversible crosslinking bonds, combining crosslinking properties and processing fluidity.

[0024] The bio-based functional additive component consists of a bio-based compound antioxidant, a bio-based lubricant, and a bio-based nucleating agent, with a mass ratio of 0.8:0.7:1. The preparation method is as follows: the bio-based compound antioxidant, bio-based lubricant, and bio-based nucleating agent are stirred and mixed at 100 rpm for 10 minutes. After mixing, the mixture is sieved through an 80-mesh standard sieve to remove agglomerated materials, thus obtaining a homogeneous bio-based functional additive component. The bio-based compound antioxidant is a vitamin... The product is formulated with vitamin E and rosemary extract in a 1:1 mass ratio. The bio-based lubricant is erucamide, a long-chain aliphatic amide lubricant that is a nonionic surfactant with good thermal stability, high lubrication efficiency, and excellent compatibility with thermoplastic polyesters. It does not plasticize or migrate. The bio-based nucleating agent is polylactic acid oligomer grafted starch, a composite nucleating agent that modifies natural starch with PLA oligomer grafting. It combines the natural nucleating characteristics of starch with the matrix compatibility of PLA oligomers. It is a crystalline nucleating agent with high nucleation efficiency and no side effects.

[0025] Example 2, a bio-based injection molding compound and its production process, is composed of the following raw materials in parts by weight: 90 parts matrix resin component, 5 parts modified reinforcing component, 2.5 parts bio-based crosslinking component, and 2.5 parts bio-based functional additive component. The preparation steps of bio-based injection molding compounds and their manufacturing process are as follows: S1. Raw material pretreatment: Vacuum dry each raw material of the matrix resin component to a moisture content ≤0.05%, pre-preparation of modified reinforcing components is completed, bio-based crosslinking components are activated, and bio-based functional additive components are pre-mixed and homogenized. S2. Raw material premixing: Add the dried matrix resin component to a high-speed mixer and mix at 1200 rpm for 3 minutes. Then add the modified reinforcing component, the activated bio-based crosslinking component and the bio-based functional additive component and mix at 800 rpm for 5 minutes for low-speed mixing. During the mixing process, control the material temperature to ≤45℃. After mixing, sieve through a 60-mesh sieve to obtain the premix. S3. Twin-screw extrusion granulation: The premixed material is added to a parallel twin-screw extruder with an L / D ratio of 40. The temperature is controlled in stages, with a range of 140 to 185°C. Three-stage vacuum devolatilization is performed with a vacuum degree of -0.085 to -0.095 MPa. After melt mixing and crosslinking, the material is extruded into strips. The strips are cooled in a 25°C water bath and then granulated. The granules are dried in a fluidized bed at 60°C for 4 hours until the moisture content is ≤0.03%, thus obtaining bio-based injection molding granules. S4. Pre-injection molding drying: The bio-based injection molding particles are vacuum dried again at 80℃ / 4h to remove trace amounts of moisture adsorbed during storage. The moisture content of the particles after drying is ≤0.03%. S5. Injection molding: The dried particles are added to a screw injection molding machine, melted in the barrel at 170-185°C, injected into the mold at 40-60°C, and demolded after holding pressure and cooling to obtain the bio-based injection molded product.

[0026] The matrix resin component consists of polylactic acid (PLA), polybutylene furanate (PBF), and polyhydroxyalkanoates (PHA), with a mass ratio of 24:8:5. The preparation method is as follows: PLA, PBF, and PHA are individually dried in a vacuum oven. The drying parameters for PLA are 85℃ / 8h and -0.09MPa, for PBF 75℃ / 6h and -0.09MPa, and for PHA 60℃ / 12h and -0.08MPa. After drying, each raw material is cooled to room temperature (≤25℃), sealed, and stored, yielding a product with a moisture content ≤0.05%. The matrix resin components include polylactic acid (PLA), a resin with a weight-average molecular weight of 120,000 and a D-type content of 4.5%. It has a linear polymer structure with high molecular chain regularity. Polybutylene furanate has an elongation at break of ≥300% and a glass transition temperature Tg=35℃. Its molecular chain contains a furan ring structure, combining the biodegradability of aliphatic polyesters with the high toughness and high heat resistance of aromatic polyesters. It has excellent thermoplastic processing performance and good compatibility with PLA. Polyhydroxy fatty acid ester is a microbially synthesized polyester, belonging to intracellular polymers. Its molecular chain is an oligomer of aliphatic hydroxy fatty acids, with strong structural flexibility, excellent low-temperature toughness, and degradation performance that can be regulated by microorganisms.

[0027] The modified reinforcing component is composed of modified nanocellulose. The preparation method of the modified reinforcing component is as follows: using nanocellulose prepared from agricultural waste as a base, a 2% concentration of nanocellulose aqueous dispersion is prepared, and 1-butyl-3-methylimidazolium acetate ionic liquid is added at 1.2% of the dispersion mass. The mixture is stirred in a constant temperature water bath at 60℃ and 300 rpm for 2 hours, and then ultrasonically dispersed at 300W power and 20kHz frequency for 30 minutes. Subsequently, it is spray-dried with an inlet air temperature of 160℃, an outlet air temperature of 80℃, and a feed rate of 5mL / min to obtain white modified nanocellulose powder. The powder has a bulk density of 0.32g / cm³ and a moisture content of ≤0.04%. The modified reinforcing component is prepared by weighing according to the weight parts. The modified nanocellulose is prepared by surface chemical modification with ionic liquid based on natural nanocellulose, and has both the high specific surface area enhancement characteristics of nanomaterials and the interface modification characteristics of ionic liquids.

[0028] The bio-based crosslinking component is composed of cashew phenol glycidyl ether-maleic anhydride copolymer. The preparation method of the bio-based crosslinking component is as follows: weigh a portion of cashew phenol glycidyl ether-maleic anhydride copolymer, add 0.1% of its mass of dibutyltin dilaurate crosslinking catalyst, mix, and place in a forced-air drying oven to preheat at 100℃ for 15 min, stirring slightly during the process to ensure uniform mixing. After preheating, quickly cool to room temperature ≤25℃, seal and store, and obtain the bio-based crosslinking component after activation treatment. The cashew phenol glycidyl ether-maleic anhydride copolymer is a functional copolymer made by grafting glycidyl ether and maleic anhydride with natural cashew phenol as the core raw material. The molecular chain contains active groups such as epoxy groups and maleic anhydride groups, and has dynamic reversible crosslinking bonds, combining crosslinking properties and processing fluidity.

[0029] The bio-based functional additive component consists of a bio-based compound antioxidant, a bio-based lubricant, and a bio-based nucleating agent, with a mass ratio of 0.8:0.7:1. The preparation method is as follows: the bio-based compound antioxidant, bio-based lubricant, and bio-based nucleating agent are stirred and mixed at 100 rpm for 10 minutes. After mixing, the mixture is sieved through an 80-mesh standard sieve to remove agglomerated materials, thus obtaining a homogeneous bio-based functional additive component. The bio-based compound antioxidant is a vitamin... The product is formulated with vitamin E and rosemary extract in a 1:1 mass ratio. The bio-based lubricant is erucamide, a long-chain aliphatic amide lubricant that is a nonionic surfactant with good thermal stability, high lubrication efficiency, and excellent compatibility with thermoplastic polyesters. It does not plasticize or migrate. The bio-based nucleating agent is polylactic acid oligomer grafted starch, a composite nucleating agent that modifies natural starch with PLA oligomer grafting. It combines the natural nucleating characteristics of starch with the matrix compatibility of PLA oligomers. It is a crystalline nucleating agent with high nucleation efficiency and no side effects.

[0030] Example 3: A bio-based injection molding compound and its production process, comprising the following raw materials in parts by weight: 95 parts matrix resin, 6 parts modified reinforcing component, 3 parts bio-based crosslinking component, and 2.5 parts bio-based functional additive component. The preparation steps of bio-based injection molding compounds and their manufacturing process are as follows: S1. Raw material pretreatment: Vacuum dry each raw material of the matrix resin component to a moisture content ≤0.05%, pre-preparation of modified reinforcing components is completed, bio-based crosslinking components are activated, and bio-based functional additive components are pre-mixed and homogenized. S2. Raw material premixing: Add the dried matrix resin component to a high-speed mixer and mix at 1200 rpm for 3 minutes. Then add the modified reinforcing component, the activated bio-based crosslinking component and the bio-based functional additive component and mix at 800 rpm for 5 minutes for low-speed mixing. During the mixing process, control the material temperature to ≤45℃. After mixing, sieve through a 60-mesh sieve to obtain the premix. S3. Twin-screw extrusion granulation: The premixed material is added to a parallel twin-screw extruder with an L / D ratio of 40. The temperature is controlled in stages, with a range of 140 to 185°C. Three-stage vacuum devolatilization is performed with a vacuum degree of -0.085 to -0.095 MPa. After melt mixing and crosslinking, the material is extruded into strips. The strips are cooled in a 25°C water bath and then granulated. The granules are dried in a fluidized bed at 60°C for 4 hours until the moisture content is ≤0.03%, thus obtaining bio-based injection molding granules. S4. Pre-injection molding drying: The bio-based injection molding particles are vacuum dried again at 80℃ / 4h to remove trace amounts of moisture adsorbed during storage. The moisture content of the particles after drying is ≤0.03%. S5. Injection molding: The dried particles are added to a screw injection molding machine, melted in the barrel at 170-185°C, injected into the mold at 40-60°C, and demolded after holding pressure and cooling to obtain the bio-based injection molded product.

[0031] The matrix resin component consists of polylactic acid (PLA), polybutylene furanate (PBF), and polyhydroxyalkanoates (PHA), with a mass ratio of 24:8:5. The preparation method is as follows: PLA, PBF, and PHA are individually dried in a vacuum oven. The drying parameters for PLA are 85℃ / 8h and -0.09MPa, for PBF 75℃ / 6h and -0.09MPa, and for PHA 60℃ / 12h and -0.08MPa. After drying, each raw material is cooled to room temperature (≤25℃), sealed, and stored, yielding a product with a moisture content ≤0.05%. The matrix resin components include polylactic acid (PLA), a resin with a weight-average molecular weight of 120,000 and a D-type content of 4.5%. It has a linear polymer structure with high molecular chain regularity. Polybutylene furanate has an elongation at break of ≥300% and a glass transition temperature Tg=35℃. Its molecular chain contains a furan ring structure, combining the biodegradability of aliphatic polyesters with the high toughness and high heat resistance of aromatic polyesters. It has excellent thermoplastic processing performance and good compatibility with PLA. Polyhydroxy fatty acid ester is a microbially synthesized polyester, belonging to intracellular polymers. Its molecular chain is an oligomer of aliphatic hydroxy fatty acids, with strong structural flexibility, excellent low-temperature toughness, and degradation performance that can be regulated by microorganisms.

[0032] The modified reinforcing component is composed of modified nanocellulose. The preparation method of the modified reinforcing component is as follows: using nanocellulose prepared from agricultural waste as a base, a 2% concentration of nanocellulose aqueous dispersion is prepared, and 1-butyl-3-methylimidazolium acetate ionic liquid is added at 1.2% of the dispersion mass. The mixture is stirred in a constant temperature water bath at 60℃ and 300 rpm for 2 hours, and then ultrasonically dispersed at 300W power and 20kHz frequency for 30 minutes. Subsequently, it is spray-dried with an inlet air temperature of 160℃, an outlet air temperature of 80℃, and a feed rate of 5mL / min to obtain white modified nanocellulose powder. The powder has a bulk density of 0.32g / cm³ and a moisture content of ≤0.04%. The modified reinforcing component is prepared by weighing according to the weight parts. The modified nanocellulose is prepared by surface chemical modification with ionic liquid based on natural nanocellulose, and has both the high specific surface area enhancement characteristics of nanomaterials and the interface modification characteristics of ionic liquids.

[0033] The bio-based crosslinking component is composed of cashew phenol glycidyl ether-maleic anhydride copolymer. The preparation method of the bio-based crosslinking component is as follows: weigh a portion of cashew phenol glycidyl ether-maleic anhydride copolymer, add 0.1% of its mass of dibutyltin dilaurate crosslinking catalyst, mix, and place in a forced-air drying oven to preheat at 100℃ for 15 min, stirring slightly during the process to ensure uniform mixing. After preheating, quickly cool to room temperature ≤25℃, seal and store, and obtain the bio-based crosslinking component after activation treatment. The cashew phenol glycidyl ether-maleic anhydride copolymer is a functional copolymer made by grafting glycidyl ether and maleic anhydride with natural cashew phenol as the core raw material. The molecular chain contains active groups such as epoxy groups and maleic anhydride groups, and has dynamic reversible crosslinking bonds, combining crosslinking properties and processing fluidity.

[0034] The bio-based functional additive component consists of a bio-based compound antioxidant, a bio-based lubricant, and a bio-based nucleating agent, with a mass ratio of 0.8:0.7:1. The preparation method is as follows: the bio-based compound antioxidant, bio-based lubricant, and bio-based nucleating agent are stirred and mixed at 100 rpm for 10 minutes. After mixing, the mixture is sieved through an 80-mesh standard sieve to remove agglomerated materials, thus obtaining a homogeneous bio-based functional additive component. The bio-based compound antioxidant is a vitamin... The product is formulated with vitamin E and rosemary extract in a 1:1 mass ratio. The bio-based lubricant is erucamide, a long-chain aliphatic amide lubricant that is a nonionic surfactant with good thermal stability, high lubrication efficiency, and excellent compatibility with thermoplastic polyesters. It does not plasticize or migrate. The bio-based nucleating agent is polylactic acid oligomer grafted starch, a composite nucleating agent that modifies natural starch with PLA oligomer grafting. It combines the natural nucleating characteristics of starch with the matrix compatibility of PLA oligomers. It is a crystalline nucleating agent with high nucleation efficiency and no side effects.

[0035] Comparative Example 1: The difference between this comparative example and Example 1 is that polybutylene furanate was not added in this comparative example.

[0036] Comparative Example 2 differs from Example 1 in that no modified nanocellulose was added in this comparative example.

[0037] Comparative Example 3 differs from Example 1 in that cashew phenol glycidyl ether-maleic anhydride copolymer was not added in this comparative example.

[0038] Performance testing: The relevant properties of the bio-based injection molding compounds and their manufacturing processes provided in Examples 1-3 and Comparative Examples 1-3 were tested respectively, and the test data are recorded in the table below:

[0039] Among them, the bio-based content of bio-based injection molding plastics prepared using the test methods in GB / T 39264-2020 were tested in Examples 1, 2, and 3, as well as Comparative Examples 1, 2, and 3. The tensile strength of bio-based injection molding compounds prepared according to the test methods in GB / T 1040.2-2006 (Examples 1, 2, 3, Comparative Examples 1, 2, and 3) was tested. The elongation at break of bio-based injection molding materials prepared according to the test methods in GB / T 1040.2-2006 were tested in Examples 1, 2, 3, Comparative Examples 1, 2, and 3.

[0040] By comparing and analyzing the relevant data in the table, it can be seen that the bio-based injection molding compound prepared by this invention significantly improves the overall mechanical properties of bio-based injection molding compounds, achieving a synergistic balance between high rigidity and high toughness. This indicates that the bio-based injection molding compound and its manufacturing process provided by this invention have broader market prospects and are more suitable for widespread application.

[0041] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A bio-based injection molding compound and its manufacturing process, characterized in that, It is composed of the following raw materials in parts by weight: 80-95 parts matrix resin component, 4-6 parts modified reinforcing component, 2-3 parts bio-based crosslinking component, and 2.5 parts bio-based functional additive component; The preparation steps of the bio-based injection molding compound and its manufacturing process are as follows: S1. Raw material pretreatment: Vacuum dry each raw material of the matrix resin component, pre-prepare the modified reinforcing component, activate the bio-based crosslinking component, and pre-mix and homogenize the bio-based functional additive component. S2. Raw material premixing: The dried matrix resin component is added to a high-speed mixer and mixed at high speed. Then, the modified reinforcing component, the activated bio-based crosslinking component and the bio-based functional additive component are added and mixed at low speed. The material temperature is controlled during the mixing process. After mixing, the material is sieved to obtain the premix. S3. Twin-screw extrusion granulation: The premixed material is added to a parallel twin-screw extruder, and after segmented temperature control, three-stage vacuum devolatilization, melt mixing and cross-linking, it is extruded into strips. After the strips are cooled, they are granulated, and the particles are dried in a fluidized bed to obtain bio-based injection molding particles. S4. Pre-injection drying: Vacuum dry the bio-based injection molding particles again to remove trace amounts of moisture adsorbed during storage; S5. Injection Molding: The dried particles are added to a screw injection molding machine, melted in the barrel, injected into the mold, held under pressure and cooled before demolding to obtain the bio-based injection molded plastic product.

2. The bio-based injection molding compound and its manufacturing process according to claim 1, characterized in that, The matrix resin component is composed of polylactic acid, polybutylene furanate, and polyhydroxyalkanoate, and the mass ratio of polylactic acid, polybutylene furanate, and polyhydroxyalkanoate is 24:8:

5.

3. The bio-based injection molding compound and its manufacturing process according to claim 2, characterized in that, The preparation method of the matrix resin component is as follows: polylactic acid, polybutylene furanate, and polyhydroxy fatty acid ester are placed in a vacuum oven and dried independently. After drying, each raw material is cooled to room temperature, sealed and stored to obtain the matrix resin component.

4. The bio-based injection molding compound and its manufacturing process according to claim 1, characterized in that, The modified reinforcing component is composed of modified nanocellulose.

5. The bio-based injection molding compound and its manufacturing process according to claim 4, characterized in that, The modified reinforcing component is prepared by using modified nanocellulose prepared from agricultural waste as a base, adding nanocellulose aqueous dispersion and 1-butyl-3-methylimidazolium acetate ionic liquid and stirring, followed by spray drying to obtain the modified reinforcing component.

6. The bio-based injection molding compound and its manufacturing process according to claim 1, characterized in that, The bio-based crosslinking component is composed of cashew phenol glycidyl ether-maleic anhydride copolymer.

7. The bio-based injection molding compound and its manufacturing process according to claim 6, characterized in that, The preparation method of the bio-based crosslinking component is as follows: take cashew phenol glycidyl ether-maleic anhydride copolymer, add dibutyltin dilaurate crosslinking catalyst, mix and preheat, and stir slightly during the process to ensure uniform mixing. After preheating, quickly cool to room temperature, seal and store, and obtain the bio-based crosslinking component after activation treatment.

8. The bio-based injection molding compound and its manufacturing process according to claim 1, characterized in that, The bio-based functional additive component consists of a bio-based compound antioxidant, a bio-based lubricant, and a bio-based nucleating agent, wherein the mass ratio of the bio-based compound antioxidant, the bio-based lubricant, and the bio-based nucleating agent is 0.8:0.7:

1.

9. The bio-based injection molding compound and its manufacturing process according to claim 8, characterized in that, The preparation method of the bio-based functional additive component is as follows: bio-based compound antioxidant, bio-based lubricant and bio-based nucleating agent are put into a small mixer, stirred and mixed, and then sieved to remove agglomerated materials to obtain a homogeneous bio-based functional additive component.

10. The bio-based injection molding compound and its manufacturing process according to claim 9, characterized in that, The bio-based compound antioxidant is a mixture of vitamin E and rosemary extract in a mass ratio of 1:

1. The bio-based lubricant is erucamide, and the bio-based nucleating agent is polylactic acid oligomer grafted starch.

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