A method for preparing plant-based bio-based plastic particles by modifying and then grinding, and application thereof
By modifying the material before grinding, the problems of reduced polymerization degree of cellulose macromolecules and uneven modification in traditional processes are solved. This method achieves uniform penetration of the modifier and retention of the cellulose aspect ratio, thereby improving the processing smoothness and product quality of plant-based bio-based plastics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU JIZHOU INNOVATION TECH CO LTD
- Filing Date
- 2026-06-05
- Publication Date
- 2026-07-21
AI Technical Summary
In traditional processes, the degree of polymerization of cellulose macromolecules in plant-based and bio-based plastics decreases after pre-crushing, the fiber skeleton is destroyed, and the modifier has difficulty penetrating deeply, resulting in uneven modification. In addition, the ultrafine powder is prone to agglomeration and clumping, which affects the smoothness of processing and product quality.
The method of first modifying and then grinding is adopted. The loose fiber bundles are formed by multi-roller crushing, spreading and opening. Combined with physical and chemical desugaring and degumming, the whole bundle is modified and then graded and ground to ensure that the modifier penetrates and coats evenly, and the degree of polymerization and aspect ratio of cellulose macromolecules are preserved, avoiding irreversible cutting and agglomeration during the crushing process.
It achieves uniform penetration and coating of the modifier, retains the degree of polymerization and aspect ratio of cellulose macromolecules, avoids irreversible cutting and agglomeration during the pulverization process, improves the modification effect and product quality, and meets the needs of high-end applications.
Smart Images
Figure CN122427451A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of bio-based plastics preparation technology, specifically to a method for preparing plant-based bio-based plastic particles by first modifying and then grinding them, and its application. Background Technology
[0002] With the global decline in reliance on fossil resources and the growing awareness of environmental protection, bio-based plastics are increasingly being used in automotive interiors, packaging materials, daily consumer goods, and textile masterbatches due to their combination of renewability, low carbon footprint, and excellent mechanical properties.
[0003] Traditional processes typically involve first crushing the plant material into powder before further processing. This pre-crushing process irreversibly breaks down the plant material, reducing the natural degree of polymerization of cellulose macromolecules, damaging the high aspect ratio of the fiber skeleton, and causing the fiber structure to collapse. Meanwhile, powdered plant materials have a mass transfer barrier that is tight on the outside and dense on the inside, making it difficult for degumming liquid and modifiers to penetrate deeply into the interior of the raw materials. Due to the tight surface and dense internal structure of the powder particles, the modifiers can only stay on the particle surface and cannot effectively modify each fiber, resulting in uneven modification effect. Furthermore, the pre-crushed ultrafine powder will generate hydrogen bond agglomeration due to the exposed hydroxyl groups, and it is also prone to clumping during storage. This not only affects the smoothness of subsequent processing, but also reduces the quality of the final product. During the grinding process, since the fibers have been pre-crushed, the grinding energy will be consumed indiscriminately on the crushed fibers, resulting in a decrease in the aspect ratio of the fiber powder. Therefore, a method for preparing plant-based bio-based plastic particles by first modifying and then grinding is proposed, along with its application. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding, and its application, in order to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing plant-based bio-based plastic particles by first modifying and then grinding, comprising the following steps: S1. Raw material pretreatment: Remove moldy and rotten parts, and cut into regular pieces of 5-20cm; S2. Mechanical rolling and splitting fiber bundles: The regular material is fed into a multi-roller rolling equipment, and through step-by-step rolling, spreading and splitting, the fibers are longitudinally burst and laterally layered to form a fluffy continuous fiber bundle with cracks.
[0006] S3. Physicochemical synergistic desugaring, degumming and impurity removal: The fiber bundles are treated by combining physical field assistance with chemical or biological treatment to open the pores of the fiber cell walls, promote the dissolution and removal of sugars, pectin, starch and hemicellulose; S4. Uniform coating modification of the whole bundle: The dry fiber bundle is fed into the high-speed mixer in the form of a whole bundle, and the modifier is added for overall modification, so that the modifier penetrates along the cracks and uniformly coats the fiber surface.
[0007] S5. Graded grinding into powder: The modified fluffy fiber bundles are ground into fiber powder of 20 mesh to 1200 mesh according to the target particle size; S6. Blending and granulation: The obtained fiber powder is blended with thermoplastic matrix resin at a fiber addition rate of 15-65%, and then melt-extruded and granulated using a twin-screw extruder.
[0008] Preferably, in S1, the raw material includes one or more of bamboo, fast-growing timber, herbaceous plants, or vines.
[0009] Preferably, in S2, the rolling pressure is 0.5–3 MPa, the rolling speed is 3–10 m / min, and the thickness of the bundle fragments after splitting is 0.2–2 mm.
[0010] Preferably, in S3, the physicochemical synergistic desugaring, degumming and impurity removal adopts one or more combinations of hot water extraction, ultrasonic synergy, micro-airflow assistance, microwave assistance and enzymatic hydrolysis.
[0011] Preferably, the physicochemical synergistic desugaring, degumming and impurity removal process is carried out at a temperature of 40-95°C for 20-120 minutes, with a desugaring rate of 92%, a degumming rate of 88%, and drying to a moisture content of 3-8%.
[0012] Preferably, in S4, the modifier includes coupling agents, lubricants, dispersants, toughening agents, heat stabilizers, and antioxidants.
[0013] Preferably, the modification temperature is 75–115°C, the rotation speed is 600–1500 r / min, the time is 10–35 min, and the coating uniformity is 95%.
[0014] Preferably, in S6, the extrusion temperature of the twin-screw extruder is 160-260°C, the main engine speed is 200-450 r / min, and the resulting granules have a moisture content of 0.8%.
[0015] Preferably, the thermoplastic matrix resin is at least one of PP, PE, ABS, PA, PLA, and PBAT.
[0016] This invention also provides an application of a method for preparing plant-based bio-based plastic particles by first modifying and then grinding them, wherein the particles are used in automotive interior and exterior trim parts, lightweight structural parts, robot parts, sports equipment, furniture, building materials, kitchen and bathroom products, daily necessities, food packaging, tableware, food preservation containers, clothing and textile accessories, shoe materials and masterbatches for functional fabrics.
[0017] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects: This invention completely overturns the traditional process of first pulverizing into powder and then processing it. It creatively employs multi-roller progressive crushing, spreading, and fiber opening, causing the plant material to selectively burst along the longitudinal weak interfaces and stratify laterally, without any pre-grinding. The fluffy fiber bundles retain the natural degree of polymerization of cellulose macromolecules and the high aspect ratio of the fiber skeleton, avoiding irreversible cutting and structural collapse caused by pre-pulverization. The dense network of fissures, micropores, and interlayer channels within the bundles pre-forms high-speed transport paths, allowing subsequent degumming liquids and modifiers to deeply penetrate. This physically breaks down the traditional method of powder being dense on the outside and tight on the inside. The mass transfer barrier allows the modifier to reach the surface of each individual fiber directly under dynamic shear dispersion and capillary action. The bundle shape prevents irreversible adhesion caused by premature fiber crushing. At the same time, when the fiber bundle with the surface wrapped with organic modification layer and toughening layer enters the grinding mill, the modification layer plays a lubricating, buffering and elastic protection role. The grinding energy is preferentially consumed in further cleavage along the original cracks rather than indiscriminate fragmentation, resulting in a high aspect ratio of fiber powder. The surface of each crushed fragment is still exposed with the modified organic interface layer, which fundamentally eliminates hydrogen bond agglomeration and storage clumping caused by exposed hydroxyl groups in ultrafine powder.
[0018] The fiber bundle's slit network is further activated by the synergistic effects of ultrasonic cavitation microjets, microwave dielectric heating, and micro-airflow. This allows mild reagents such as hot water, dilute alkali, or biological enzymes to enter the intercellular spaces of the fiber cells through activation channels, specifically hydrolyzing pectin, hemicellulose, starch, and sugars. This avoids etching the cellulose backbone, resulting in near-complete removal of pectin and sugars. This fundamentally eliminates the caramelization and yellowing of sugars and the off-odors caused by the thermal decomposition of pectin during subsequent high-temperature processing. The product meets the stringent requirements for automotive interiors and food contact applications, while the inherent strength of the fiber is fully preserved.
[0019] In a high-speed mixer, loose fiber bundles are dispersed by shearing and their own elasticity, allowing the modifier microdroplets to capillarily penetrate along the pore network to the surface of each individual fiber. One end of the coupling agent is chemically bonded to the hydroxyl groups of the fiber or strongly physically adsorbed, while the other end has a chain segment with good compatibility with the target plastic matrix. The toughening agent forms a flexible transition layer on the fiber surface. The lubricant and dispersant weaken the friction between fibers, so that the fibers in the bundle are fully coated and can slide and separate from each other. The overall bundle shape avoids irreversible adhesion caused by premature crushing, and each fiber is endowed with an integrated interface modification layer.
[0020] When modified fiber powder is blended with matrices such as PP, PE, ABS, PA, PLA, and PBAT in a twin-screw extruder at 160–260°C, the pre-set modified layer on the fiber surface undergoes melt diffusion, chain entanglement, or co-crystallization with the matrix molecular chains, forming a continuous and dense interfacial transition zone. Coarse-particle-size fibers provide structural reinforcement in a high aspect ratio skeleton morphology; medium and ultrafine-particle-size fibers can be directly used in high-appearance thin-walled parts or textile masterbatches, with a smooth surface and no exposed fibers. Thanks to the complete interface formed by whole-bundle modification, even with a fiber filling amount as high as 15–65%, the composite material does not crack, delaminate, or absorb water and swell. The reinforcement effect is improved by 30–50% compared to traditional powder processes, and there is no yellowing or odor throughout the process, fully meeting the needs of high-end applications. Attached Figure Description
[0021] Figure 1 This is a flowchart of the particle preparation method of the present invention. Detailed Implementation
[0022] Example 1 Please see Figure 1 This invention provides a technical solution: a method for preparing plant-based bio-based plastic particles by first modifying and then grinding, comprising the following steps: S1. Raw material pretreatment: Remove moldy and rotten parts, and cut into regular pieces of 5-20cm; Raw materials include one or more of bamboo, fast-growing wood, herbaceous plants or vines; wood, herbs or vines are peeled and nodes are removed to obtain the pure fiber layer; bamboo is cleaned of green and yellow. Bamboo materials include moso bamboo, nan bamboo or ci bamboo, etc.; fast-growing timber includes paulownia, poplar, pine, eucalyptus or fir, etc.; herbaceous plants include reed, reed or miscanthus, etc.; vines include natural vines or vine cores, etc. S2. Mechanical rolling and splitting fiber bundles: The regular material is fed into a multi-roller rolling equipment, and through step-by-step rolling, spreading and splitting, the fibers are longitudinally burst and laterally layered to form a loose and continuous fiber bundle with cracks; the fiber skeleton and aspect ratio are completely preserved, and the looseness is increased by 60%, making subsequent degumming, modification and grinding very easy.
[0023] The compaction pressure is 0.5–3 MPa, the compaction speed is 3–10 m / min, and the thickness of the split bundles is 0.2–2 mm.
[0024] S3. Physicochemical synergistic desugaring, degumming and impurity removal: The fiber bundles are treated by combining physical field assistance with chemical or biological treatment to open the pores of the fiber cell walls, promote the dissolution and removal of sugars, pectin, starch and hemicellulose; Physicochemical synergistic desugaring, degumming and impurity removal employs one or more combinations of hot water extraction, ultrasonic synergy, micro-airflow assistance, microwave assistance, and enzymatic hydrolysis.
[0025] The physicochemical synergistic desugaring, degumming and impurity removal process is carried out at a temperature of 40-95℃ for 20-120 min, with a desugaring rate of 92% and a degumming rate of 88%, and is dried to a moisture content of 3-8%.
[0026] By using physical fields to open the pores of fiber cell walls, sugars, pectin, starch, hemicellulose and other substances are dissolved. Then, a mild reagent is used to complete the deep impurity removal without damaging the fiber body. It is environmentally friendly and efficient. S4. Uniform coating modification of the whole bundle: The dry fiber bundle is fed into the high-speed mixer in the form of a whole bundle, and the modifier is added for overall modification, so that the modifier penetrates along the cracks and uniformly coats the fiber surface. Modifiers include coupling agents, lubricants, dispersants, toughening agents, heat stabilizers, and antioxidants.
[0027] According to parts by weight, the modifier contains 0.4-2.5% coupling agent, 0.3-1.8% lubricant and dispersant, 3-18% toughening agent, and 0.15-0.8% heat stabilizer and antioxidant; the coupling agent includes one or more of silane, titanate, aluminate or MAH grafting, and the toughening agent includes one or more of POE, EPDM, MBS or TPU; The modification temperature is 75–115℃, the rotation speed is 600–1500 r / min, the time is 10–35 min, and the coating uniformity is 95%.
[0028] S5. Graded grinding into powder: The modified fluffy fiber bundles are ground into fiber powder of 20 mesh to 1200 mesh according to the target particle size; Because the fibers are pre-broken and loose, grinding is extremely smooth, and the particle size of the powder produced by graded grinding is well controlled. Coarse particle size is controlled at 2080 mesh, used for structural reinforcement materials; The particle size is controlled at 100-300 mesh, and it is used for general mass production materials; The ultrafine particle size is controlled at 400-1200 mesh, and it is used for high-appearance fine parts or textile masterbatches. The grinding process yields a 75% output and a 25% loss rate, and the fiber powder exhibits no agglomeration or coking.
[0029] S6. Blending and granulation: The obtained fiber powder is blended with thermoplastic matrix resin at a fiber addition rate of 15-65%, and then melt-extruded and granulated using a twin-screw extruder to obtain plant-based bio-based plastic granules.
[0030] The extrusion temperature of the twin-screw extruder is 160-260℃, the main machine speed is 200-450 r / min, the moisture content of the resulting granules is 0.8%, and the thermoplastic matrix resin is at least one of PP, PE, ABS, PA, PLA, and PBAT.
[0031] Working principle or structural principle: This invention employs multi-roller progressive crushing, spreading, and fiber opening, causing plant raw materials to selectively burst along the longitudinal weak interface under a pressure of 0.5–3 MPa and a speed of 3–10 m / min, and to separate into transverse layers, forming continuous and fluffy fiber bundles with a thickness of 0.2–2 mm and a 60% increase in looseness. This process preserves the natural degree of polymerization of cellulose macromolecules and the aspect ratio of the fiber skeleton. At the same time, a dense network of cracks, micropores, and interlayer channels is constructed inside and on the surface of the fiber bundles. The pre-formed pores provide a high-speed transport path for the deep penetration of subsequent degumming liquid and modifiers. This physical structure breaks through the mass transfer barrier of traditional powdered state with a tight outer layer and dense inner layer, which is a prerequisite for achieving overall high-efficiency processing.
[0032] The slit network of the fiber bundle is further activated under the action of the physical field: the ultrasonic cavitation effect generates instantaneous high-pressure microjets in the micropores, tearing apart the remaining cell wall pores; microwave dielectric heating causes polar sugars, pectin, and hemicellulose molecules to vibrate violently and peel off from the inside of the fiber; micro-airflow assists in enhancing convection and accelerates the diffusion of dissolved substances into the main solution.
[0033] At this point, mild reagents such as hot water, dilute alkali, or biological enzymes at temperatures of 40–95°C enter the intercellular spaces of the fiber cells through activated pores, specifically hydrolyzing pectin, hemicellulose, starch, and sugars while avoiding etching of the cellulose backbone. The desugaring rate is 92%, and the degumming rate is 88%, eliminating the sources of caramelization and yellowing of sugars and the off-odors produced by pectin thermal decomposition during subsequent high-temperature processing, while fully preserving the inherent strength of the fiber. Drying to a moisture content of 3–8% balances the fiber's flexibility with the control of subsequent hydrolytic side reactions of the modifiers. In traditional powder modification, microfibers agglomerate severely due to their high specific surface area and hydrogen bonding, blocking the modifier. In this invention, the dry, fluffy fiber bundles are fed into a high-speed mixer as a whole. Using the shearing and dispersion at 600-1500 r / min and the elasticity of the fiber bundles themselves, the microdroplets of modifier are allowed to capillarily penetrate along the constructed pore network and reach the surface of each individual fiber.
[0034] At 75–115°C, one end of the coupling agent chemically bonds or strongly physically adsorbs with the hydroxyl groups on the fiber surface, while the other end has a well-compatible chain segment with the target plastic matrix; the toughening agent forms a flexible transition layer on the fiber surface; the lubricant and dispersant weaken the friction between fibers, ensuring that the fibers in the bundle are fully coated and can slide and separate from each other. The overall bundle shape prevents irreversible adhesion between fibers due to premature crushing, resulting in a final coating uniformity of 95%. Each fiber is endowed with an integrated interface modification layer, laying the molecular-level connection foundation for subsequent grinding and reinforcement.
[0035] When the modified fibers that have been bundled but not cut into short enter the grinding mill, their surface is already covered with an organic modification layer and a toughening layer, which play a role in lubrication, buffering and elastic protection. This significantly reduces the collision and breakage between fibers and the direct impact damage to the fibers by the grinding media. The grinding energy is preferentially consumed in further cleavage along the existing cracks in the fibers, rather than indiscriminately breaking them down. Therefore, the fiber powder can still retain a high aspect ratio.
[0036] The surface of each pulverized fiber fragment is still exposed as a modified organic interface layer, rather than bare cellulose hydroxyl groups. This fundamentally eliminates the problem of secondary agglomeration and storage clumping caused by hydrogen bonds in ultrafine powder. Therefore, even when ground to 400-1200 mesh, the powder remains loose and free from agglomeration and local overheating and coking. The yield is 75% and the loss rate is 25%, achieving safe and low-cost mass production of ultrafine plant fiber powder.
[0037] When the obtained fiber powder is blended with thermoplastic matrices such as PP, PE, ABS, PA, PLA, and PBAT in a twin-screw extruder, the pre-prepared modified layer on the fiber surface and the matrix molecular chains undergo melting diffusion, chain entanglement, or co-crystallization at 160–260°C, forming a continuous and dense interfacial transition zone.
[0038] Coarse-grained fibers (20–80 mesh) provide structural reinforcement with a high aspect ratio skeleton; medium-grained (100–300 mesh) and ultrafine-grained (400–1200 mesh) fibers can be directly used in high-appearance thin-walled parts or textile masterbatches, with smooth surfaces and no exposed fibers. Thanks to the integrity interface formed by whole-bundle modification, even with a fiber filling content as high as 15–65%, the material still exhibits stability without cracking, delamination, or water absorption and swelling, and the reinforcement effect is 30–50% higher than that of traditional powder processing. At the same time, since heat-labile substances such as sugars and pectins have been completely removed, there is no yellowing or odor during processing and use, meeting the stringent requirements for automotive interiors and food contact applications.
[0039] Example 2 The difference between this embodiment and Embodiment 1 is that this invention also provides an application of a method for preparing plant-based bio-based plastic particles by first modifying and then grinding them. The particles are used in automotive interior and exterior trim parts, lightweight structural parts, robot parts, sports equipment, furniture, building materials, kitchen and bathroom products, daily necessities, food packaging, tableware, food preservation containers, clothing and textile accessories, shoe materials, and masterbatches for functional fabrics.
[0040] Example 3 The difference between this embodiment and Embodiments 1 and 2 is that it involves the preparation of bamboo-based PP automotive structural components granules. A1. Take bamboo, remove the green and yellow parts, and cut it into 10cm strips; A2. Rolling and splitting the fiber bundles: Three rollers are used for step-by-step rolling at a pressure of 1.8 MPa and a speed of 5 m / min to obtain loose and continuous fiber bundles. A3. Ultrasonic-Hot Water Synergistic Desugaring and Degumming: The fiber bundle is immersed in an 85℃ hot water bath and simultaneously subjected to 40kHz ultrasonic treatment for 60 minutes, achieving a desugaring rate of 94% and a degumming rate of 92%. The fiber bundle is then dried to a moisture content of 5%. A4. Bundle Modification: The formulation, based on fiber bundle weight, contains 1.2% silane coupling agent KH-550, 0.6% zinc stearate, 8% POE, and 0.3% antioxidant. It is treated in a high-speed mixer at 95℃ and 1200r / min for 20min, with a coating uniformity of 97%. A5. Grinding: Grind and sieve using a disc grinder to obtain 80-mesh fiber powder, with a yield of 96%; A6. Mixed granulation: 55 parts PP, 40 parts bamboo fiber powder, 5 parts compatibilizer and other additives are extruded and granulated by twin-screw extruder at 175-190℃; The resulting particles have a tensile strength of 38 MPa, a flexural strength of 45 MPa, and a VOC content of 10 g / g, making them suitable for automotive door panels, seat frames, and robot structural components.
[0041] Example 4 The difference between this embodiment and Embodiments 1, 2 and 3 is that: poplar-reed composite ABS household appliance exterior parts granules are prepared; B1. Mix poplar wood and reed in a 1:1 mass ratio, remove the bark and extract the fibers, and cut them. B2, rolling and splitting pressure 1.2MPa, speed 8m / min; B3. Micro-airflow-enzymatic hydrolysis synergistic degumming: Micro-airflow is introduced into the enzymatic hydrolysate at 55℃ and treated for 90 min, with a degumming rate of 90%. After washing with water, the product is dried. B4. Bundle modification: 0.9% titanate coupling agent, 0.5% PE wax, and 5% MBS are mixed at 100°C for 15 minutes. B5. Grind to 200 mesh, yield 92%; B6. Blending and granulation: 62 parts ABS, 35 parts fiber powder, 3 parts additives, extrusion temperature 190~220℃.
[0042] The resulting particle impact strength is 8.5 kJ / m. 2 After injection molding, the surface roughness is Ra0.8μm, and it is used for appliance housings, furniture, lighting fixtures, etc.
[0043] Example 5 The difference between this embodiment and Embodiments 1, 2, 3, and 4 is that it involves preparing food-grade biodegradable tableware granules made from paulownia wood PLA. C1. Take the bark and core of the paulownia wood, gently split the bundles, and crush it with a pressure of 0.8 MPa; C2. Microwave-hot water desugaring: Microwave-assisted treatment in 90℃ hot water for 45 minutes, desugaring rate of 95%, followed by thorough water washing to remove impurities; C3, food-grade modified, using coupling agents and additives with food contact certification; C4. Grind to 400 mesh; C5. Blending and granulation: 60 parts PLA, 38 parts wood flour, 2 parts food-grade additives, extrusion temperature 160-180℃.
[0044] The resulting granules pass food contact safety tests, are completely degradable, and are heat resistant up to 110℃, making them suitable for lunch boxes, trays, bottle caps, and fresh food packaging.
[0045] Example 6 The difference between this embodiment and Embodiments 1, 2, 3, 4, and 5 is that it involves the preparation of ultrafine bamboo powder TPU textile and apparel functional particles. D1. Finely split bamboo fibers to obtain fully fluffy microfiber bundles; D2. Ultrasonic micro-airflow deep impurity removal, with extremely low impurity residue; D3. After whole-bundle modification, the powder is ground to 1000 mesh, and there is no agglomeration of the powder, resulting in good flowability. D4. Blend with TPU for modification and granulation.
[0046] The resulting granules are soft, skin-friendly, antibacterial, and breathable, and can be used in clothing accessories, shoe materials, and functional fabric masterbatches. In summary, this invention completely overturns the traditional process of first pulverizing into powder and then processing it. It creatively employs multi-roller progressive crushing, spreading, and fiber opening, causing the plant material to selectively burst along the longitudinal weak interfaces and stratify laterally, without any pre-grinding. The fluffy fiber bundles retain the natural degree of polymerization of cellulose macromolecules and the high aspect ratio of the fiber skeleton, avoiding irreversible cutting and structural collapse caused by pre-pulverization. The dense network of fissures, micropores, and interlayer channels within the bundles pre-forms high-speed transport paths, allowing subsequent degumming liquid and modifiers to deeply penetrate. This physically breaks down the traditional powder state of being dense on the outside and tight on the inside. The mass transfer barrier allows the modifier to reach the surface of each individual fiber directly under dynamic shear dispersion and capillary action. The bundle shape prevents irreversible adhesion caused by premature fiber crushing. At the same time, when the fiber bundle with the surface wrapped with organic modification layer and toughening layer enters the grinding mill, the modification layer plays a lubricating, buffering and elastic protection role. The grinding energy is preferentially consumed in further cleavage along the original cracks rather than indiscriminate fragmentation, resulting in a high aspect ratio of fiber powder. The surface of each crushed fragment is still exposed with the modified organic interface layer, which fundamentally eliminates the hydrogen bond agglomeration and storage agglomeration caused by exposed hydroxyl groups in ultrafine powder.
[0047] The fiber bundle's slit network is further activated by the synergistic effects of ultrasonic cavitation microjets, microwave dielectric heating, and micro-airflow. This allows mild reagents such as hot water, dilute alkali, or biological enzymes to enter the intercellular spaces of the fiber cells through activation channels, specifically hydrolyzing pectin, hemicellulose, starch, and sugars. This avoids etching the cellulose backbone, resulting in near-complete removal of pectin and sugars. This fundamentally eliminates the caramelization and yellowing of sugars and the off-odors caused by the thermal decomposition of pectin during subsequent high-temperature processing. The product meets the stringent requirements for automotive interiors and food contact applications, while the inherent strength of the fiber is fully preserved.
[0048] In a high-speed mixer, loose fiber bundles are dispersed by shearing and their own elasticity, allowing the modifier microdroplets to capillarily penetrate along the pore network to the surface of each individual fiber. One end of the coupling agent is chemically bonded to the hydroxyl groups of the fiber or strongly physically adsorbed, while the other end has a chain segment with good compatibility with the target plastic matrix. The toughening agent forms a flexible transition layer on the fiber surface. The lubricant and dispersant weaken the friction between fibers, so that the fibers in the bundle are fully coated and can slide and separate from each other. The overall bundle shape avoids irreversible adhesion caused by premature crushing, and each fiber is endowed with an integrated interface modification layer.
[0049] When modified fiber powder is blended with matrices such as PP, PE, ABS, PA, PLA, and PBAT in a twin-screw extruder at 160–260°C, the pre-set modified layer on the fiber surface undergoes melt diffusion, chain entanglement, or co-crystallization with the matrix molecular chains, forming a continuous and dense interfacial transition zone. Coarse-particle-size fibers provide structural reinforcement in a high aspect ratio skeleton morphology; medium and ultrafine-particle-size fibers can be directly used in high-appearance thin-walled parts or textile masterbatches, with a smooth surface and no exposed fibers. Thanks to the complete interface formed by whole-bundle modification, even with a fiber filling amount as high as 15–65%, the composite material does not crack, delaminate, or absorb water and swell. The reinforcement effect is improved by 30–50% compared to traditional powder processes, and there is no yellowing or odor throughout the process, fully meeting the needs of high-end applications.
[0050] Those skilled in the art will understand that the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.
Claims
1. A method for preparing plant-based bio-based plastic particles by first modifying and then grinding them, characterized in that, Includes the following steps: S1. Raw material pretreatment: Remove moldy and rotten parts, and cut into regular pieces of 5-20cm; S2. Mechanical rolling and splitting fiber bundles: The regular material is fed into a multi-roller rolling equipment, and through step-by-step rolling, spreading and splitting, the fibers are longitudinally burst and laterally layered to form a fluffy continuous fiber bundle with cracks. S3. Physicochemical synergistic desugaring, degumming and impurity removal: The fiber bundles are treated by combining physical field assistance with chemical or biological treatment to open the pores of the fiber cell walls, promote the dissolution and removal of sugars, pectin, starch and hemicellulose; S4. Uniform coating modification of the whole bundle: The dry fiber bundle is fed into the high-speed mixer in the form of a whole bundle, and the modifier is added for overall modification, so that the modifier penetrates along the cracks and uniformly coats the fiber surface. S5. Graded grinding into powder: The modified fluffy fiber bundles are ground into fiber powder of 20 mesh to 1200 mesh according to the target particle size; S6. Blending and granulation: The obtained fiber powder is blended with thermoplastic matrix resin at a fiber addition rate of 15-65%, and then melt-extruded and granulated using a twin-screw extruder.
2. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 1, characterized in that, In S1, the raw materials include one or more of bamboo, fast-growing timber, herbaceous plants, or vines.
3. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 1, characterized in that, In S2, the rolling pressure is 0.5–3 MPa, the rolling speed is 3–10 m / min, and the thickness of the bundle fragments after splitting is 0.2–2 mm.
4. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 1, characterized in that, In S3, the physicochemical synergistic desugaring, degumming and impurity removal adopts one or more combinations of hot water extraction, ultrasonic synergy, micro-airflow assistance, microwave assistance and enzymatic hydrolysis.
5. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 4, characterized in that, The physicochemical synergistic desugaring, degumming and impurity removal process is carried out at a temperature of 40-95℃ for 20-120 minutes, with a desugaring rate of 92% and a degumming rate of 88%, and is dried to a moisture content of 3-8%.
6. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 1, characterized in that, In S4, the modifier includes coupling agents, lubricants, dispersants, toughening agents, heat stabilizers, and antioxidants.
7. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 6, characterized in that, The modification temperature is 75–115℃, the rotation speed is 600–1500 r / min, the time is 10–35 min, and the coating uniformity is 95%.
8. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 1, characterized in that, In S6, the extrusion temperature of the twin-screw extruder is 160-260°C, the main machine speed is 200-450 r / min, and the resulting granules have a moisture content of 0.8%.
9. The method for preparing plant-based bio-based plastic particles by pre-modification and subsequent grinding according to claim 8, characterized in that, The thermoplastic matrix resin is at least one of PP, PE, ABS, PA, PLA, and PBAT.
10. An application of a method for preparing plant-based bio-based plastic particles according to claims 1-9, characterized in that, Applications of the particles in masterbatches for automotive interior and exterior trim parts, lightweight structural parts, robot parts, sports equipment, furniture, building materials, kitchen and bathroom products, daily necessities, food packaging, tableware, food preservation containers, clothing and textile accessories, footwear materials, and functional fabrics.