Low-temperature melting regeneration preparation method of resin fiber plastic honeycomb composite board

Abstract

The invention relates to the technical field of high polymer material recycling, and discloses a low-temperature melting regeneration preparation method of a resin fiber plastic honeycomb composite board, and the preparation method comprises the following steps: premixing and coating crushed materials, polypropylene wax and N, N '-ethylene bis stearamide; then low-temperature extrusion is performed through a main feeding port, and a liquid-phase carrier formed by melting polypropylene wax is used for wrapping the semi-molten crushed material and conveying the semi-molten crushed material; then adding reactive repair master batches containing a functionalized elastomer and zinc stearate through a side feeding port; under the action of a shear field, zinc ions and an elastomer are induced to be subjected to a coordination reaction to construct an ionic cross-linked network, and finally, regenerated particles are obtained through vacuum devolatilization and granulation. Liquid-phase lubrication protection and in-situ chemical tackifying are realized through a step-by-step feeding process, mechanical crushing of glass fibers in the processing process is effectively reduced, interface bonding of a resin matrix and the fibers is reconstructed, and the tensile strength, flexural modulus and notch impact performance of the regenerated material are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of polymer material recycling technology, specifically a low-temperature melt regeneration method for preparing resin fiber plastic honeycomb composite panels. Background Technology

[0002] Resin fiber plastic honeycomb composite panels are widely used in logistics packaging, automotive interiors, and building materials due to their lightweight, high strength, corrosion resistance, and good cushioning properties. With the continuous growth in the production of these materials, the amount of waste generated during production and processing, as well as the amount of discarded panels at the end of their service life, is increasing daily. Therefore, recycling and reusing these panels has significant environmental and economic value.

[0003] Currently, the recycling of such thermoplastic composites mainly employs physical crushing followed by melt granulation. However, since these sheets are typically composed of a polypropylene matrix and glass fiber reinforcement, they face a significant contradiction between matrix degradation and fiber damage during secondary processing. In conventional melt extrusion processes, increasing the processing temperature is usually necessary to reduce melt viscosity and thus decrease mechanical shear stress on the glass fibers. However, this leads to severe thermo-oxidative degradation of the polypropylene matrix, resulting in a decrease in molecular weight and deterioration of mechanical properties. Conversely, if a low-temperature extrusion process is used to inhibit matrix degradation, the high viscosity of the polypropylene melt generates enormous shear stress, causing the rigid glass fibers to break severely during screw conveying, resulting in a significant reduction in their length and loss of reinforcement.

[0004] Furthermore, after initial processing and long-term use, the interfacial bonding layer between the resin matrix and glass fiber in waste composite boards is often damaged. Traditional recycling granulation processes only involve simple physical mixing, which is insufficient to repair the interfacial defects between the resin and fiber at the microscopic level. This leads to debonding at the interface when the recycled material is subjected to stress, resulting in a significant reduction in notched impact strength and tensile strength, making it difficult to meet the application requirements of high-value-added products. Therefore, how to achieve effective plasticization of the resin at low temperatures while minimizing damage to fiber length, and simultaneously repair the interfacial bonding force in situ during processing, is a pressing technical challenge in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a low-temperature melt regeneration method for preparing resin fiber plastic honeycomb composite panels. This method solves the problems in existing resin fiber plastic honeycomb composite panel recycling processes, such as severe glass fiber breakage due to low-temperature, high-viscosity melt shearing and significant degradation of the mechanical properties of recycled materials due to interfacial bonding failure.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing resin fiber plastic honeycomb composite panels by low-temperature melt regeneration, comprising the following steps: S1. Raw material premixing and liquid film coating: Weigh waste resin fiber plastic honeycomb composite board crushed material, polypropylene wax and N,N'-ethylene bis-stearamide, mix them at room temperature so that the polypropylene wax and N,N'-ethylene bis-stearamide coat the surface of the crushed material to obtain a premix. S2, Low-temperature feeding and carrier phase change: The premixed material is added through the main feed port of the extruder. The temperature of the low-temperature feeding and carrier phase change zone of the extruder is set so that the polypropylene wax melts to form a liquid carrier, which encapsulates the crushed material in a semi-molten state and transports it. S3, Side Feeding Reaction Initiation: Reactive repair masterbatch containing functionalized elastomer and zinc stearate is added through the side feeding port located downstream of the main feed port of the extruder. The temperature of the side feeding mixing and liquid phase penetration zone is set so that the zinc stearate melts and penetrates into the resin and fiber interface. S4. In-situ thickening and rheological reversal: When the material enters the in-situ thickening and reaction control zone, zinc ions are induced to undergo a coordination reaction with the functionalized elastomer under the action of a shear field, thereby constructing an ionic cross-linking network. S5. Deviation and Forming: After the material undergoes vacuum devolatilization in the devolatilization and pressure-stabilized extrusion zone, it is extruded and granulated by the die head to obtain recycled modified particles.

[0007] This invention, through the above-described process steps, utilizes a strategy combining stepwise feeding and quasi-low-temperature chemical modification to achieve high performance in recycled materials. Its specific mechanism of action and beneficial effects are as follows: Physical lubrication and protection of fibers are achieved through a cryogenic liquid-phase carrier. In step S2, the low melting point and low viscosity of polypropylene wax and N,N'-ethylene bis-stearamide are utilized to preferentially melt them within a near-crescent temperature range of 160°C to 165°C. The molten polypropylene wax forms a continuous low-viscosity liquid film within the extruder, suspending and encapsulating the not-yet-fully-melted resin matrix particles and rigid glass fibers. This transforms the dry friction between the solid material and the screw and barrel into liquid-phase lubrication. This measure significantly reduces shear resistance during processing, effectively suppresses the damage to the aspect ratio of glass fibers caused by mechanical shearing, and allows the recycled material to retain a longer fiber skeleton, thereby maintaining a high flexural modulus.

[0008] In-situ ionic coordination reactions are used to achieve melt thickening and interface reinforcement. In steps S3 and S4, reactive repair masterbatch containing zinc stearate and functionalized elastomers is introduced via side feeding. Zinc stearate melts at the processing temperature and penetrates to the microscopic interface between the resin and fiber. The dissociated zinc ions act as coordination centers, reacting with polar groups on the functionalized elastomer chain segments. This reaction constructs a physical ionic cross-linking network within the melt, restricting molecular chain slippage. This structure reconstructs the rheological properties of the melt, achieving a recovery of melt strength in the later stages of processing, and endowing the recycled material with excellent tensile strength and heat deformation resistance.

[0009] This invention resolves the conflict between flowability and strength by employing a step-by-step side-feeding process. The lubricating and reactive components are added at different times. In the main feeding stage, only lubricant is added, ensuring the material is conveyed and initially plasticized at low viscosity, avoiding premature thickening reactions that could lead to increased viscosity and fiber breakage. The side-feeding stage then triggers the cross-linking reaction. By this time, the fibers are uniformly dispersed and the matrix is ​​plasticized, and the resulting ionic network strengthens the interfacial bonding. This process design protects fiber length, enhances matrix strength, and significantly improves the notched impact resistance of the material.

[0010] Preferably, the weight proportions of the raw materials in steps S1 and S3 are as follows: 100 parts by weight of waste resin fiber plastic honeycomb composite board crushed material; 1.6-2.8 parts by weight of polypropylene wax; 0.4-0.7 parts by weight of N,N'-ethylene bis-stearamide; and 4.5-7.5 parts by weight of reactive repair masterbatch.

[0011] Using this preferred ratio ensures that the liquid carrier is sufficient to form a complete lubricating film, while also ensuring that the zinc ions provided by the reactive masterbatch and the functionalized elastomer can form a cross-linked network of appropriate density, avoiding processing difficulties caused by excessive cross-linking or limited performance improvement caused by insufficient cross-linking.

[0012] Preferably, the temperature of the low-temperature feeding and carrier phase change zone of the extruder is 155℃-170℃, and the screw speed is 220rpm-280rpm; the temperature of the side-feeding mixing and liquid phase penetration zone is 160℃-175℃.

[0013] By using these process parameters, the temperature is strictly controlled near the melting limit of polypropylene crystals, which ensures the complete melting of polypropylene wax and avoids thermal oxidative degradation of the matrix resin. Combined with a specific screw speed, it provides a suitable residence time and shear rate, ensuring uniform plasticization of the material.

[0014] Preferably, the temperature of the in-situ thickening and reaction control zone is 160℃-175℃, the temperature of the devolatilization and pressure stabilization extrusion zone is 165℃-180℃, and the die head temperature is 170℃-180℃.

[0015] This temperature setting allows the temperature control curve to show a gradual, slight increase, which adapts to the gradually increasing melt viscosity as the ion crosslinking network is constructed, ensuring the stability of the extrusion process and the quality of granulation.

[0016] Preferably, the polypropylene wax has a weight-average molecular weight (Mw) of 5000 g / mol to 6000 g / mol and a softening point of 140°C to 145°C; the N,N'-ethylene bis-stearamide has a melting point of 142°C to 146°C.

[0017] To ensure that its melting temperature is highly matched with the semi-melting temperature range of the waste board, an effective liquid phase lubrication layer is formed in the early stage of processing.

[0018] Preferably, the reactive repair masterbatch is made from the following components in parts by weight: 55-65 parts by weight of metallocene polypropylene; 27-33 parts by weight of glycidyl methacrylate-grafted polyolefin elastomer; and 8-12 parts by weight of zinc stearate.

[0019] Using this masterbatch formulation, and with high-flowability metallocene polypropylene as a carrier, pre-dispersion of high-viscosity elastomers and small-molecule zinc salts was achieved. The ratio of zinc stearate to grafted elastomer was optimized to ensure that the stoichiometry of zinc ions to graft groups was close to the reaction equivalence in subsequent reactions, thereby maximizing ionic crosslinking efficiency.

[0020] Preferably, the reactive repair masterbatch is prepared by the following steps: mixing metallocene polypropylene, glycidyl methacrylate-grafted polyolefin elastomer, and zinc stearate in a high-speed mixer to obtain a premix, with the discharge temperature controlled below 60°C; adding the premix to an extruder for melt extrusion, controlling the material temperature to always be below 140°C, and obtaining the final product after air-cooled die hot cutting granulation and drying; wherein, the temperature of each section of the extruder is set to 85°C-140°C.

[0021] The preparation process uses a temperature below 140°C to ensure that zinc stearate is physically dispersed without undergoing chemical decomposition or reaction, while preserving the reactivity of the active groups in the grafted elastomer so that they are activated and react in situ during the final regeneration granulation process.

[0022] Preferably, the glycidyl methacrylate-grafted polyolefin elastomer uses ethylene-octene copolymer as the matrix and has a grafting rate greater than 0.8 wt%; the zinc content in the zinc stearate is 10.5 wt% to 11.5 wt%.

[0023] To ensure sufficient reaction sites and adequate coordination centers, a high-density interface enhancement network is constructed.

[0024] Preferably, the waste resin fiber plastic honeycomb composite board crushed material includes a matrix resin and a reinforcing material, wherein the matrix resin is isotactic polypropylene, the reinforcing material is alkali-free glass fiber, the mass content of the reinforcing material is 40wt%, and the particle size of the crushed material is 10mm to 20mm, and the moisture content is less than 0.5wt%.

[0025] Because for rigid composite materials with high glass fiber content, the method of this invention can better demonstrate its technical advantages in protecting fiber length and reconstructing interfacial bonding force.

[0026] Preferably, the vacuum degree of the vacuum devolatilization is maintained between -0.06 MPa and -0.09 MPa; the granulation method is a water ring hot cutting process.

[0027] Using the above process, the high vacuum effectively removes impurities and volatiles, reducing internal defects in the particles; the water ring hot cutting process is adapted to the characteristics of high-filler melt strength and rapid cooling, ensuring the particle appearance and packing density.

[0028] This invention provides a low-temperature melt-regeneration method for preparing resin fiber plastic honeycomb composite panels. It has the following beneficial effects: 1. This invention introduces polypropylene wax and N,N'-ethylene bis-stearamide during the low-temperature extrusion stage, causing them to preferentially form a low-viscosity liquid phase layer before the resin matrix melts, thus encapsulating the semi-molten crushed material for conveying. This process transforms the strong mechanical friction between the solid material and the screw and barrel into liquid-phase lubrication, effectively suppressing the glass fiber breakage problem caused by high-intensity shearing, and maximizing the preservation of the aspect ratio of the reinforcing fibers, thereby giving the recycled material a higher flexural modulus and notched impact strength. 2. This invention utilizes side-feeding technology to introduce reactive repair masterbatch containing functionalized elastomers and zinc stearate. Under the action of a shear field, zinc ions are induced to undergo in-situ coordination reactions with polar groups on the grafted segments of the elastomer, constructing a physical ionic cross-linking network. This ionic network structure enhances the interfacial compatibility between the non-polar polypropylene matrix and the polar glass fiber, and increases the melt viscosity through the physical anchoring effect between molecular chains. This solves the problem of decreased mechanical properties caused by thermal degradation of conventional recycled materials, and significantly improves the tensile strength of the material. 3. This invention employs a step-by-step feeding process, spatially separating the lubrication and plasticizing process from the reaction and thickening process. In the main feeding stage, only lubricant is added to ensure material transport under low load, avoiding premature thickening reactions that could lead to excessive energy consumption or channel blockage. In the side feeding stage, reaction masterbatch is added, initiating cross-linking enhancement after the matrix has been uniformly plasticized. This process design ensures both the rheological stability of the extrusion process and effective control over the degree of reaction, resulting in regenerated particles with regular appearance and uniform properties. Attached Figure Description

[0029] Figure 1 Figure 1 shows a comparison of the dynamic rheological properties of different recycled materials of the present invention at 170°C; wherein, Figure (a) is a graph showing the trend of storage modulus with angular frequency; and Figure (b) is a graph showing the trend of complex viscosity with angular frequency. Figure 2 Figure 1 shows a comparison of the rheological behavior and thermal history of materials during the mixing process under different feeding conditions according to the present invention; wherein, Figure 2(a) shows the trend of mixing torque over time; and Figure 3(b) shows the trend of material temperature over time. Figure 3 The figures are comparative statistics of the microstructure of glass fibers inside the recycled material of the present invention; wherein, Figure (a) is a comparative figure of the weight-average retained length of glass fibers; and Figure (b) is a comparative figure of the proportion of short fiber fragments with a length of less than 0.2 mm. Figure 4 The figures show a comparison of the physical and mechanical properties of the regenerated modified particles of the present invention; wherein, Figure (a) is a comparison of tensile strength; Figure (b) is a comparison of flexural modulus; and Figure (c) is a comparison of notched impact strength. Figure 5 Figure 1 shows a comparison of the heat deformation resistance and thermo-oxidative aging stability of the recycled material of the present invention; wherein, Figure 2(a) is a comparison of heat deformation temperature; and Figure 3(b) is a comparison of the impact strength retention rate after aging at 110°C for 500 hours. Detailed Implementation

[0030] The technical solutions in 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.

[0031] To achieve the above objectives, the present invention provides the following technical solution: The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0032] Waste resin fiber plastic honeycomb composite board crushed material: The matrix resin is isotactic polypropylene, the reinforcing material is alkali-free glass fiber, the fiber mass content is 40wt%, the board is mechanically crushed and air-separated for dust removal to obtain sheet material with a particle size of 10mm to 20mm, and the moisture content is controlled below 0.5wt%.

[0033] Polypropylene wax: weight average molecular weight Mw is 5000 g / mol to 6000 g / mol, softening point is 140℃ to 145℃, CAS number is 9003-07-0; N,N'-ethylene bis-stearamide (EBS): melting point is 142℃ to 146℃, CAS number is 110-30-5.

[0034] Metallocene polypropylene: Melt flow rate (MFR) (230℃, 2.16kg) is 20g / 10min, CAS number is 9003-07-0; Glycidyl methacrylate grafted polyolefin elastomer (POE-g-GMA): Based on ethylene-octene copolymer, grafting rate is greater than 0.8wt%, melt flow rate (MFR) is 3.5g / 10min; Zinc stearate: Zinc content is 10.5wt% to 11.5wt%, melting point is 120℃, CAS number is 557-05-1.

[0035] Zinc oxide: purity greater than 99.7%, average particle size less than 50nm, CAS number 1314-13-2; stearic acid: CAS number 57-11-4.

[0036] Preparation Example 1: This preparation example provides a method for preparing a reactive repair masterbatch, including the following steps: Raw material weighing: Weigh 60 parts by weight of metallocene polypropylene, 30 parts by weight of glycidyl methacrylate grafted polyolefin elastomer (POE-g-GMA), and 10 parts by weight of zinc stearate. Low-temperature mixing: Put the above raw materials into a high-speed mixer, set the speed to 350 rpm, the mixing time to 4 minutes, and control the discharge temperature below 55℃ to obtain a premix; Low-temperature extrusion granulation: The premixed material is added to a twin-screw extruder for melt extrusion. The temperature of each section is set as follows: feeding section 90℃, plasticizing section 135℃, homogenizing section 135℃, die head temperature 135℃; screw speed is 150 rpm. Post-processing: The extruded strip is granulated by hot cutting through an air-cooled die, dried, and then sealed and packaged to obtain reactive repair masterbatch A. During this preparation process, the material temperature is consistently controlled below 140℃ to ensure complete physical dispersion of zinc stearate and to prevent thermally induced ring-opening reactions of the GMA groups.

[0037] Preparation Example 2: This preparation example provides a method for preparing a reactive repair masterbatch, including the following steps: Raw material weighing: Weigh 55 parts by weight of metallocene polypropylene, 33 parts by weight of glycidyl methacrylate grafted polyolefin elastomer (POE-g-GMA), and 12 parts by weight of zinc stearate. Low-temperature mixing: Put the above raw materials into a high-speed mixer, set the speed to 400 rpm, the mixing time to 3 minutes, and control the discharge temperature at 58℃ to obtain a premix; Low-temperature extrusion granulation: The premixed material is added to a twin-screw extruder for melt extrusion. The temperature of each section is set as follows: feeding section 95℃, plasticizing section 140℃, homogenizing section 140℃, die head temperature 140℃; screw speed is 160 rpm. Post-processing: The extruded strip is granulated by hot cutting through an air-cooled die, dried, and then sealed and packaged to obtain reactive repair masterbatch B.

[0038] Preparation Example 3: This preparation example provides a method for preparing a reactive repair masterbatch, including the following steps: Raw material weighing: Weigh 65 parts by weight of metallocene polypropylene, 27 parts by weight of glycidyl methacrylate grafted polyolefin elastomer (POE-g-GMA), and 8 parts by weight of zinc stearate. Low-temperature mixing: Put the above raw materials into a high-speed mixer, set the speed to 300 rpm, the mixing time to 5 minutes, and control the discharge temperature at 50℃ to obtain a premix; Low-temperature extrusion granulation: The premixed material is added to a twin-screw extruder for melt extrusion. The temperature of each section is set as follows: feeding section 85℃, plasticizing section 130℃, homogenizing section 135℃, die head temperature 135℃; screw speed is 140 rpm. Post-processing: The extruded strip is granulated by hot cutting through an air-cooled die, dried, and then sealed and packaged to obtain reactive repair masterbatch C.

[0039] Example 1: This example provides a low-temperature melt-regeneration method for preparing resin fiber plastic honeycomb composite panels, including the following steps: (1) Raw material premixing and liquid film coating: Weigh 100 parts by weight of waste resin fiber plastic honeycomb composite board crushed material, add 2.0 parts by weight of polypropylene wax and 0.5 parts by weight of N,N'-ethylene bis-stearamide; put the above raw materials into a low-speed tumbling mixer and mix for 8 minutes at room temperature so that the polypropylene wax and N,N'-ethylene bis-stearamide are evenly coated on the surface of the crushed material to obtain the premix; (2) Low temperature feeding and carrier phase change: The premixed material is added through the main feed port of the co-rotating parallel twin-screw extruder. The temperature of the low temperature feeding and carrier phase change zone of the extruder is set to 160°C to 165°C, and the screw speed is 250 rpm. During this stage, the polypropylene wax melts first to form a liquid carrier, which wraps the crushed material in a semi-molten state and conveys it forward. (3) Side feeding reaction initiation: 6.0 parts by weight of reactive repair masterbatch A obtained in Preparation Example 1 were added quantitatively through the side feed port located in the extruder; the temperature of the side feeding mixing and liquid phase penetration zone was set to 165°C to 170°C; a mixing element was set downstream of the side feed port to melt the zinc stearate in the reactive repair masterbatch A and penetrate into the resin and fiber interface. (4) In-situ thickening and rheological reversal: The material enters the in-situ thickening and reaction control zone, and the temperature is set to 165℃ to 170℃; this section is equipped with a reverse conveying element to establish melt pressure, induce zinc ions and grafts to undergo coordination reaction, and construct an ion cross-linking network. (5) Deviation and molding: The material enters the devolatilization and pressure stabilization extrusion zone, and the temperature is set to 170℃ to 175℃. The die temperature is set to 175℃. The vacuum pump is started to keep the vacuum level between -0.08MPa and -0.09MPa to remove volatiles. The melt is extruded through the die head and granulated by water ring hot cutting process to obtain recycled modified particles.

[0040] Example 2: This example provides a low-temperature melt-regeneration method for preparing resin fiber plastic honeycomb composite panels, including the following steps: (1) Raw material premixing and liquid film coating: Weigh 100 parts by weight of waste resin fiber plastic honeycomb composite board crushed material, add 2.4 parts by weight of polypropylene wax and 0.6 parts by weight of N,N'-ethylene bis-stearamide; put the above raw materials into a low-speed tumbling mixer and mix for 10 minutes at room temperature to obtain premixed material; (2) Low temperature feeding and carrier phase change: The premixed material is added through the main feed port of the co-rotating parallel twin-screw extruder. The temperature of the low temperature feeding and carrier phase change zone of the extruder is set to 155℃ to 160℃, and the screw speed is 220rpm. (3) Side-feeding reaction initiation: 7.5 parts by weight of the reactive repair masterbatch B obtained in Preparation Example 2 were added through the side feed port located in the extruder; the temperature of the side-feeding mixing and liquid phase penetration zone was set to 160°C to 165°C; (4) In-situ thickening and rheological reversal: The material enters the in-situ thickening and reaction control zone, and the temperature is set to 160℃ to 165℃; (5) Deviation and molding: The material enters the devolatilization and pressure stabilization extrusion zone, and the temperature is set to 165℃ to 170℃. The die temperature is set to 170℃. The vacuum degree is maintained at -0.06MPa to -0.08MPa. The melt is extruded through the die head and granulated by water ring hot cutting process to obtain recycled modified particles.

[0041] Example 3: This example provides a low-temperature melt-regeneration method for preparing resin fiber plastic honeycomb composite panels, including the following steps: (1) Raw material premixing and liquid film coating: Weigh 100 parts by weight of waste resin fiber plastic honeycomb composite board crushed material, add 1.6 parts by weight of polypropylene wax and 0.4 parts by weight of N,N'-ethylene bis-stearamide; put the above raw materials into a low-speed tumbling mixer and mix for 5 minutes at room temperature to obtain premixed material; (2) Low temperature feeding and carrier phase change: The premixed material is added through the main feed port of the co-rotating parallel twin-screw extruder. The temperature of the low temperature feeding and carrier phase change zone of the extruder is set to 165℃ to 170℃, and the screw speed is 280rpm. (3) Side-feeding reaction initiation: 5.0 parts by weight of the reactive repair masterbatch C obtained in Preparation Example 3 were added through the side feed port located in the extruder; the temperature of the side-feeding mixing and liquid phase penetration zone was set to 170°C to 175°C; (4) In-situ thickening and rheological reversal: The material enters the in-situ thickening and reaction control zone, and the temperature is set to 170℃ to 175℃; (5) Deviation and molding: The material enters the devolatilization and pressure stabilization extrusion zone, and the temperature is set to 175℃ to 180℃. The die temperature is set to 180℃. The vacuum degree is maintained at -0.07MPa to -0.09MPa. The melt is extruded through the die head and granulated by water ring hot cutting process to obtain recycled modified particles.

[0042] Example 4: This example provides a low-temperature melt-regeneration method for preparing resin fiber plastic honeycomb composite panels, including the following steps: (1) Raw material premixing and liquid film coating: Weigh 100 parts by weight of waste resin fiber plastic honeycomb composite board crushed material, add 2.8 parts by weight of polypropylene wax and 0.7 parts by weight of N,N'-ethylene bis-stearamide; put the above raw materials into a low-speed tumbling mixer and mix for 8 minutes at room temperature to obtain premixed material; (2) Low-temperature feeding and carrier phase change: The process parameters are the same as in Example 1, except that the temperature of the low-temperature feeding and carrier phase change zone is set to 160°C to 165°C and the screw speed is 250 rpm. (3) Side-feeding reaction initiation: 6.0 parts by weight of the reactive repair masterbatch A obtained in Preparation Example 1 were added through the side feed port located in the extruder; the temperature of the side-feeding mixing and liquid phase penetration zone was set to 165°C to 170°C; (4) In-situ thickening and rheological reversal: The material enters the in-situ thickening and reaction control zone, and the temperature is set to 165℃ to 170℃; (5) Deviation and molding: The process parameters are the same as in Example 1, except that the temperature of the devolatilization and pressure stabilization extrusion zone is set to 170°C to 175°C and the die temperature is 175°C. After vacuum devolatilization, the particles are extruded and granulated to obtain the recycled modified particles.

[0043] Example 5: This example provides a low-temperature melt-regeneration method for preparing resin fiber plastic honeycomb composite panels, including the following steps: (1) Raw material premixing and liquid film coating: Weigh 100 parts by weight of waste resin fiber plastic honeycomb composite board crushed material, add 2.0 parts by weight of polypropylene wax and 0.5 parts by weight of N,N'-ethylene bis-stearamide; the mixing process is the same as in Example 1; (2) Low-temperature feed and carrier phase change: The process parameters are the same as in Example 1, and the temperature of the low-temperature feed and carrier phase change zone is set to 160°C to 165°C; (3) Side-feeding reaction initiation: 4.5 parts by weight of the reactive repair masterbatch A obtained in Preparation Example 1 were added through the side feed port located in the extruder; the temperature of the side-feeding mixing and liquid phase penetration zone was set to 165°C to 170°C. (4) In-situ thickening and rheological reversal: The material enters the in-situ thickening and reaction control zone, and the temperature is set to 165℃ to 170℃; (5) Deviation and molding: The process parameters are the same as in Example 1, except that the temperature of the devolatilization and pressure stabilization extrusion zone is set to 170°C to 175°C and the die temperature is 175°C. After vacuum devolatilization, the particles are extruded and granulated to obtain the recycled modified particles.

[0044] Comparative Example 1: Compared with Example 1, the difference is that the reactive repair masterbatch used in step (3) was not prepared with zinc stearate. Specifically, the raw materials were changed to 70 parts by weight of metallocene polypropylene and 30 parts by weight of glycidyl methacrylate grafted polyolefin elastomer, without zinc stearate. The remaining steps and parameters were the same as in Example 1.

[0045] Comparative Example 2: Compared with Example 1, the difference is that the reactive repair masterbatch used in step (3) was prepared with an equal weight of zinc oxide instead of zinc stearate. Specifically, referring to the process of Preparation Example 1, the raw materials were changed to 60 parts by weight of metallocene polypropylene, 30 parts by weight of glycidyl methacrylate grafted polyolefin elastomer, and 10 parts by weight of zinc oxide. The remaining steps and parameters were the same as in Example 1.

[0046] Comparative Example 3: Compared with Example 1, the difference is that in step (1), polypropylene wax and N,N'-ethylene bis-stearamide were not added, and the crushed material was directly fed into the extruder. The other steps and parameters were the same.

[0047] Comparative Example 4: Compared with Example 1, the difference is that the temperature of each section of the extruder is set to 220°C to 230°C, and the other steps and raw material ratios are the same.

[0048] Comparative Example 5: Compared with Example 1, the difference is that the side feeding operation was cancelled, and the reactive repair masterbatch A (6.0 parts by weight) was mixed with the crushed material, polypropylene wax and N,N'-ethylene bis-stearamide in step (1) and added through the main feed port. All other parameters were the same.

[0049] Test Example 1: This test case aims to verify, through dynamic rheological testing, whether an ionic cross-linked network has been successfully constructed within the recycled material, and the effectiveness of liquid zinc salts compared to solid zinc sources in constructing this network.

[0050] The regenerated modified particles prepared in Examples 1, 4, 1, 2 and 4 were placed in a vacuum oven and dried at 80°C for 4 hours to remove moisture.

[0051] A rotational rheometer was used, equipped with a parallel plate fixture with a diameter of 25 mm, and the plate spacing was set to 1.0 mm.

[0052] Set the test temperature to 170℃, load the sample after the fixture temperature stabilizes, and scrape off the excess melt overflowing from the edge after the sample melts. Let it stand for 3 minutes to eliminate thermal history and loading stress.

[0053] Strain scanning was performed within the strain range of 0.1% to 100% to determine the linear viscoelastic region of each sample, and then dynamic frequency scanning was performed at 1.0% strain value.

[0054] The frequency scan range was set from 0.1 rad / s to 100 rad / s, and the energy storage modulus (G) at different angular frequencies was recorded. ' ) and complex viscosity (η) * )data.

[0055] The experimental data are shown in Table 1. Table 1: Dynamic rheological test data of each group of recycled materials at 170℃.

[0056] in conclusion:

[0057] According to Table 1 and Figure 1 The data shows that in the low-frequency region, the energy storage modulus G in Example 1... ' Reaching 4256.3 Pa, complex viscosity η * The value reached as high as 45210.5 Pa·s. In comparison, the G in Comparative Example 1 (zinc-free system) was... ' The Pa is only 124.5 Pa, and the complex viscosity is only 8450.6 Pa·s. This order-of-magnitude difference indicates a significant rheological property shift in Example 1. In Comparative Example 1, due to the lack of a zinc ion source, the system exhibits only physical entanglement of molecular chains, displaying typical liquid-like behavior (G...' ∝ω 2 In Example 1, the liquid support formed by the melting of zinc stearate transports zinc ions to the graft interface, inducing the ring-opening of the GMA groups and their reaction with Zn. 2+ Coordination bonds are formed. This ionic cluster structure acts as a physical cross-linking point, restricting the movement of molecular chains during long relaxation times, endowing the melt with significant solid-like characteristics and high melt strength, and verifying the successful construction of the ionic cross-linking network.

[0058] Comparative Example 2 G ' Although slightly higher than Comparative Example 1, it was far lower than Example 1. This confirms the crucial role of the liquid-phase permeation mechanism. Zinc oxide is a solid phase at the processing temperature and cannot melt and wet the micro-interface like zinc stearate. This makes it difficult for zinc ions to access the GMA groups encapsulated at the phase interface, limiting reaction efficiency and preventing the formation of an effective global cross-linked network.

[0059] Example 4 increased the amount of rheological carrier, and its rheological data were similar to but slightly lower than those of Example 1. This indicates that, provided the ion source is sufficient, appropriately increasing the amount of lubricant did not damage the main structure of the crosslinked network, and the system still maintained high melt strength, verifying the stability of the process under high carrier content.

[0060] Comparative Example 4 (high-temperature process) showed the lowest levels of all rheological properties, especially at low frequency G. ' Only 85.2 Pa. This is because although high temperature (220℃-230℃) reduces physical viscosity, it also leads to thermal degradation of the polypropylene matrix and a decrease in molecular weight. Furthermore, at high temperature, the dissociation rate of ionic coordination bonds is greater than the association rate, making it impossible to maintain an effective network structure.

[0061] In summary, Example 1 constructs a reversible ionic cross-linking network inside the melt through liquid-phase carrier delivery and in-situ reaction at near-low temperature, solving the problem of weak interfacial bonding that is usually associated with low-temperature processing, and achieving a balance between melt strength and processing fluidity.

[0062] Test Example 2: This test example uses a torque rheometer to simulate the extrusion process. By monitoring the torque changes of the material at different time points, it verifies the stepwise control mechanism of lubrication before reaction and the phase change behavior of the liquid carrier in this invention.

[0063] Prepare experimental raw materials. The raw material components corresponding to Example 1 (crushed material, polypropylene wax, EBS, masterbatch A) and the fully mixed raw material corresponding to Comparative Example 5 were dried in an 80°C forced-air drying oven for 4 hours and then cooled to room temperature in a desiccator for later use.

[0064] A Hack torque rheometer was selected, a Banbury type internal mixer rotor was installed, the chamber temperature was set to 160℃, the rotor speed was set to 60rpm, and the data sampling frequency was 1Hz.

[0065] For the step-by-step feeding process of simulated Example 1: After the program is started, the mixed crushed material, polypropylene wax and EBS are first added, and the cavity is compacted and sealed by the feeding pusher; at time t=180s (simulated material reaches the side feed port), the feeding port is quickly opened to add reactive repair masterbatch A, and then compacted and mixed until 600s is completed.

[0066] For the simulated comparative example 5 full mixing process: after the program starts, the crushed material, polypropylene wax, EBS and reactive repair masterbatch A are all added to the mixing chamber at one time, and compacted using the feeding pusher. The mixing is continued for 600 seconds under the same temperature and speed conditions.

[0067] During the experiment, the changes in material temperature and torque over time were recorded in real time. Each experiment was repeated three times, and the median value was taken after removing outliers with obvious operational errors.

[0068] The experimental data are shown in Table 1: Table 2. Data record of torque and temperature evolution during the mixing process of materials at 160℃.

[0069] in conclusion: According to Table 2 and Figure 2 According to the data, in the first 180 seconds of the experiment, the torque of Example 1 rapidly decreased from the peak feed rate of 42.5 N·m to 12.8 N·m, and the material temperature remained at 162.1 °C, only slightly higher than the set temperature. This indicates that the polypropylene wax undergoes a rapid phase change at 160 °C, forming a liquid-phase carrier that encapsulates the solid resin and fibers, establishing an effective hydrodynamic lubrication layer and significantly reducing the dry friction resistance between particles. In contrast, the torque of Comparative Example 5 remained above 30 N·m during the same period, and the material temperature rose more rapidly. This is because the fully mixed feed caused premature contact between zinc stearate and POE-g-GMA in the reactive masterbatch, initiating an interfacial cross-linking reaction before the material was fully plasticized, increasing the system viscosity and leading to severe shear heat generation.

[0070] After 180 seconds, the reactive masterbatch from Example 1 was added, and the torque began to show a reversal upward trend, gradually climbing from 12.8 N·m to 26.5 N·m at 600 s. This data change confirms the occurrence of the in-situ thickening mechanism: as zinc stearate melts and penetrates, zinc ions and grafts undergo coordination reactions at the liquid interface, constructing an ion cluster network, which significantly improves the melt strength in the latter half. This process not only restores the mechanical properties of the material, but also, due to sufficient lubrication in the early stage, the final material temperature (165.8 °C) is still controlled within the near-low temperature range, avoiding thermal degradation of the matrix.

[0071] In contrast, Comparative Example 5 showed a decreasing torque trend in the later stages, dropping from 26.2 N·m at 300 s to 21.9 N·m at 600 s, while the material temperature soared to 177.1 °C. This indicates that the shear heat generated by the premature reaction led to the thermal degradation of the polypropylene matrix, or that the high shear in the early stages damaged the fiber structure, resulting in a decrease in the support strength of the melt structure. Experimental data shows that only through spatiotemporal separation process control can the desired effect of first protecting the fibers with low viscosity and then strengthening the matrix with high viscosity be achieved.

[0072] Test Example 3: This test case aims to evaluate the impact of different process conditions on the energy consumption of the extruder and the protective effect on the microstructure of glass fibers in recycled materials, and to verify the practical effectiveness of quasi-low temperature liquid phase carrier technology in reducing shear damage.

[0073] In the extrusion granulation production process of Examples 1-5 and Comparative Examples 3-4, the control system (DCS) built into the extruder was used to continuously record the main machine current and melt pressure data after the production reached a steady state. The sampling time was 10 minutes, and the arithmetic mean was calculated.

[0074] 20g of particles were randomly selected from each of the above-mentioned granulated products and placed in a ceramic crucible for calcination in a muffle furnace. The heating program was set as follows: the temperature was increased to 600℃ at a rate of 10℃ / min and held at a constant temperature for 4 hours until the matrix resin was completely decomposed and carbonized, leaving only inorganic glass fibers.

[0075] After the crucible has cooled to room temperature, the remaining glass fiber ash is removed, deionized water is added to make a suspension, and the suspension is placed in an ultrasonic cleaner for 30 seconds to prevent fiber agglomeration. Then the suspension is dropped onto a glass slide.

[0076] The fiber morphology was observed at 50x magnification using an optical microscope equipped with an image analysis system. Five fields of view were randomly selected for each sample group, and the length data of no less than 500 glass fibers in each field of view were statistically analyzed using ImageJ software.

[0077] The weight-average fiber retention length of each group of samples was calculated based on statistical data. The calculation formula is: ,in For length is The number of fibers.

[0078] The experimental data are shown in Table 3: Table 3. Statistical data on extrusion processing energy consumption parameters and glass fiber morphology

[0079] in conclusion: According to Table 3 and Figure 3 According to the data, the average current of the main unit in Example 1 was 142.5A, significantly lower than the 215.8A in Comparative Example 3. In the absence of polypropylene wax and EBS, Comparative Example 3 experienced direct solid dry friction between the rigid glass fibers in the crushed material and the screw and barrel, resulting in a surge in torque and increased energy consumption. This high-intensity mechanical shearing directly led to severe fiber breakage, with a weight-average fiber retention length of only 0.34mm and fragments shorter than 0.2mm accounting for as much as 68.5%.

[0080] In contrast, Example 1, by introducing a liquid-phase rheological carrier in the 160°C-165°C range, suspends the semi-molten resin matrix and glass fiber in a low-viscosity liquid film, significantly reducing the interfacial friction coefficient. This hydrodynamic lubrication effect not only reduces the main engine current by approximately 34%, but also effectively buffers the impact of shear force on the fibers, resulting in a final product with a weight-average fiber retention length of 0.98 mm, nearly three times that of Comparative Example 3.

[0081] A comparison with the conventional high-temperature process in Comparative Example 4 further reveals the advantages of the quasi-low-temperature process. Although high temperatures (220℃-230℃) can reduce the viscosity of the matrix resin, in the initial stages of the solid transport and melting sections, the lack of a liquid-phase carrier means that the breakage process of the rigid honeycomb panels is still accompanied by significant mechanical shearing. Furthermore, the polymer thermal degradation caused by high temperatures reduces the melt's ability to encapsulate and protect the fibers. Data from Example 4 further confirms that appropriately increasing the rheology carrier content can further reduce processing resistance, thereby maximizing the preservation of the fiber aspect ratio.

[0082] In summary, the quasi-low temperature liquid phase carrier process of the present invention reduces processing energy consumption while effectively preserving the length of glass fibers, laying a microstructural foundation for improving the mechanical properties of recycled materials.

[0083] Test Example 4: This test case, based on internationally accepted standards, involves injection molding and mechanical property testing of the recycled modified particles prepared in each embodiment and comparative example. The aim is to comprehensively evaluate the synergistic strengthening effect of interfacial ionic thickening and long fiber retention mechanisms on the tensile, bending, and impact properties of the final material.

[0084] The recycled granules obtained in Examples 1-5 and Comparative Examples 1-5 were placed in a forced-air drying oven and dried at 90°C for 4 hours to remove absorbed moisture. The dried granules were then used to prepare standard mechanical test specimens using an injection molding machine. The injection molding process parameters were set as follows: barrel temperature 175°C-185°C-190°C-190°C, mold temperature 40°C, injection pressure 80 MPa, holding pressure 65 MPa, and cooling time 20 seconds.

[0085] The prepared dumbbell-shaped tensile specimens and long strip-shaped bending / impact specimens were placed in a constant temperature and humidity laboratory at 23±2℃ and 50±5% relative humidity for 48 hours to eliminate internal stress and reach moisture absorption equilibrium.

[0086] Using a universal testing machine, the tensile rate was set to 50 mm / min, and the tensile strength and elongation at break were recorded. Five parallel samples were tested in each group, and the arithmetic mean was taken.

[0087] Replace the three-point bending fixture and conduct bending performance tests according to ISO178 standard. Set the span to 64mm and the test rate to 2mm / min. Record the bending modulus and bending strength. Test 5 parallel samples in each group.

[0088] The notched impact strength was tested using a cantilever beam impact testing machine. A type A notch with a radius of 0.25 mm was pre-machined on the specimen using a notching machine. The test temperature was 23℃, and the energy absorbed per unit area at fracture was recorded. Ten parallel specimens were tested in each group, and the maximum and minimum values ​​were discarded before taking the average.

[0089] The experimental data are shown in Table 4: Table 4 Summary of Test Results of Physical and Mechanical Properties of Recycled Materials

[0090] in conclusion: According to Table 4 and Figure 4 Comparative analysis of the data shows that the flexural modulus is mainly affected by the retained length of the glass fibers. The flexural modulus of Example 1 is as high as 3450 MPa, significantly higher than that of Comparative Examples 3 and 4. Combined with the conclusions of Test Example 3, it can be seen that Comparative Example 3, due to the lack of liquid-phase carrier lubrication, resulted in a large number of fiber breakages during processing; while Comparative Example 4, although reducing viscosity, caused matrix degradation, leading to a decrease in the ability of the fibers to transfer stress to the matrix. Example 1, through quasi-low temperature liquid-phase lubrication technology, effectively preserved the long fiber structure, thereby endowing the material with excellent flexural rigidity.

[0091] Notched impact strength and tensile strength are mainly affected by the interfacial bonding state and ionic cross-linking network. The impact strength of Example 1 is 2.3 times that of Comparative Example 1. In Comparative Example 1, although the elastomer POE-g-GMA is present, due to the lack of zinc ion coordination, only physical adsorption or weak hydrogen bonding exists at the interface. When subjected to impact, cracks easily propagate rapidly along the phase interface. In Example 1, however, the Zn introduced by liquid phase infiltration... 2+ It forms a high-density ionic complex with the GMA group. This ionic bond can dissipate a large amount of energy when subjected to external impact, and at the same time induces the formation of crazes, which significantly improves the toughness of the material.

[0092] Furthermore, the impact strength of Comparative Example 2 was between that of Example 1 and Comparative Example 1, indicating that although partial reaction could occur in the solid-phase mixture, the limited contact area prevented the formation of a cross-linked network covering the entire interface. In Comparative Example 5, the reaction occurred too early, leading to an premature increase in system viscosity, which affected subsequent plasticization and fiber dispersion, resulting in greater fluctuations in mechanical properties and an overall performance lower than that of Example 1.

[0093] In summary, this invention solves the performance inversion problem commonly faced by recycled waste composite board materials, namely, high rigidity accompanied by high brittleness or high toughness accompanied by low modulus, through a dual reinforcement mechanism of long fiber skeleton and ionic bond interface.

[0094] Test Example 5: This test case aims to evaluate the effect of ion crosslinking networks on improving the heat deformation resistance of recycled materials, and to verify the performance retention rate of the materials under long-term heat load through high-temperature aging experiments, thereby determining their applicability under high-temperature conditions.

[0095] Injection-molded specimens from Examples 1, 4, and 5, as well as Comparative Examples 1, 3, and 4, were selected. The specimens conformed to ISO 75 standards, measuring 80mm × 10mm × 4mm, with 20 specimens prepared for each group. The specimens were conditioned in a standard laboratory environment for 48 hours.

[0096] The heat distortion temperature was tested using a Vicat thermometer. The sample was placed flat on a support with a span of 64 mm. A bending stress of 1.82 MPa was applied, and the heating rate was 120 °C / h. The temperature at which the center deflection of the sample reached 0.34 mm was recorded. Three samples were tested in each group, and the average value was taken.

[0097] Long-term thermo-oxidative aging tests were conducted. The remaining samples were vertically suspended in a precision forced-air drying oven, and the aging temperature was set to 110℃ (simulating the environment of an automobile engine compartment or high-temperature components), while maintaining forced air convection inside the oven.

[0098] After 500 hours of continuous aging, the sample strip was removed, cooled at room temperature, and conditioned for 24 hours.

[0099] The aged specimens were subjected to notched impact strength tests, and the impact strength values ​​after aging were recorded. The performance retention rate was calculated using the formula: (Aging impact strength / Initial impact strength) × 100%.

[0100] The experimental data are shown in Table 5: Table 5 Test data on heat distortion temperature and thermo-oxidative aging performance retention rate

[0101] in conclusion: According to Table 5 and Figure 5 Regarding the heat distortion temperature (HDT), Example 1 reached 138.4℃, which is 13.8℃ and 25.6℃ higher than Comparative Example 1 and Comparative Example 3, respectively. HDT mainly reflects the rigidity of the material under load and the ability of molecular chain segments to move. Comparative Example 3, due to the lack of rheological carrier protection, had extremely short glass fiber retention lengths, failing to form an effective skeletal support, resulting in a significant decrease in heat resistance. Although Comparative Example 1 retained a certain fiber length, the lack of zinc ion crosslinking meant that the matrix resin and elastomer were only physically blended, making it prone to molecular chain segment slippage at high temperatures. The ion cluster structure introduced by Example 1 through in-situ reaction acts as a physical crosslinking point at high temperatures, restricting the large-scale thermal movement of polymer molecular chain segments, thereby improving the material's heat distortion resistance under load.

[0102] Regarding thermo-oxidative aging stability, Example 1 exhibited a performance retention rate as high as 87.1% after aging, while Comparative Example 1 only retained 59.6%, and Comparative Example 4 even dropped to 47.6%. Comparative Example 4, having undergone high-temperature processing at 220-230°C, had numerous thermo-oxidative degradation initiation points in its matrix resin molecular chains. This accelerated chain-splitting reactions during the subsequent aging process at 110°C, leading to a sharp decline in mechanical properties. In Comparative Example 1, due to weak interfacial bonding, microcracks and debonding easily formed at the resin-glass fiber interface during prolonged thermal expansion and contraction cycles, resulting in a significant decrease in impact strength after aging.

[0103] Conversely, the quasi-low temperature process in Example 1, at 160-175°C, maximized the preservation of the molecular weight and chemical structure integrity of the matrix resin. Simultaneously, the ionic crosslinking network formed a stable compatibility layer at the interface, effectively blocking oxygen penetration into the deeper layers and inhibiting the propagation of microcracks. Even with the increased content of low molecular weight polypropylene wax in Example 4, due to the strong binding effect of the ionic crosslinking network, its HDT and retention rate did not show a significant decrease, indicating that this chemical modification method is sufficient to offset the plasticizing effect of the lubricant, ensuring the reliability of the recycled material under high-temperature conditions.

[0104] 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 method for preparing resin fiber plastic honeycomb composite panels by low-temperature melt regeneration, characterized in that, Includes the following steps: S1. Weigh the waste resin fiber plastic honeycomb composite board crushed material, polypropylene wax and N,N'-ethylene bis-stearamide, and mix them at room temperature so that the polypropylene wax and N,N'-ethylene bis-stearamide coat the surface of the crushed material to obtain a premix. S2. The premixed material is added through the main feed port of the extruder. The temperature of the low-temperature feed and carrier phase change zone of the extruder is set so that the polypropylene wax melts to form a liquid carrier, which encapsulates the crushed material in a semi-molten state and transports it. S3. Add reactive repair masterbatch containing functionalized elastomer and zinc stearate through the side feed port located downstream of the main feed port of the extruder, set the temperature of the side feed mixing and liquid phase penetration zone, so that the zinc stearate melts and penetrates into the resin and fiber interface. S4. The material enters the in-situ thickening and reaction control zone, where zinc ions are induced to coordinate with the functionalized elastomer under the action of a shear field, thereby constructing an ionic cross-linking network. S5. After the material undergoes vacuum devolatilization in the devolatilization and pressure-stabilized extrusion zone, it is extruded and granulated by the die head to obtain recycled modified particles.

2. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 1, characterized in that, The weight proportions of the raw materials in steps S1 and S3 are as follows: 100 parts by weight of crushed waste resin fiber plastic honeycomb composite board; 1.6-2.8 parts by weight of polypropylene wax; 0.4-0.7 parts by weight of N,N'-ethylene bis-stearamide; 4.5-7.5 parts by weight of reactive repair masterbatch.

3. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 1, characterized in that, The temperature of the low-temperature feed and carrier phase change zone is 155℃-170℃, and the screw speed is 220rpm-280rpm. The temperature of the side-feeding mixing and liquid phase permeation zone is 160℃-175℃.

4. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 1, characterized in that, The temperature of the in-situ thickening and reaction control zone is 160℃-175℃, the temperature of the devolatilization and pressure stabilization extrusion zone is 165℃-180℃, and the die head temperature is 170℃-180℃.

5. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 1, characterized in that, The polypropylene wax has a weight-average molecular weight (Mw) of 5000 g / mol to 6000 g / mol and a softening point of 140°C to 145°C; the N,N'-ethylene bis-stearamide has a melting point of 142°C to 146°C.

6. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 1, characterized in that, The reactive repair masterbatch is made from components comprising the following parts by weight: Metallocene polypropylene: 55-65 parts by weight; Glycidyl methacrylate grafted polyolefin elastomer: 27-33 parts by weight; Zinc stearate: 8-12 parts by weight.

7. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 6, characterized in that, The reactive repair masterbatch is prepared through the following steps: Metallocene polypropylene, glycidyl methacrylate-grafted polyolefin elastomer and zinc stearate are mixed in a high-speed mixer to obtain a premix, and the discharge temperature is controlled below 60℃. The premixed material is added to an extruder for melt extrusion, and the material temperature is controlled to always be below 140℃. After air-cooled die hot cutting granulation and drying, the product is obtained. The temperature of each section of the extruder is set to 85℃-140℃.

8. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 6, characterized in that, The glycidyl methacrylate-grafted polyolefin elastomer uses ethylene-octene copolymer as the matrix and has a grafting rate greater than 0.8 wt%; the zinc content in the zinc stearate is 10.5 wt% to 11.5 wt%.

9. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 1, characterized in that, The waste resin fiber plastic honeycomb composite board crushed material includes a matrix resin and a reinforcing material, wherein the matrix resin is isotactic polypropylene, the reinforcing material is alkali-free glass fiber, the mass content of the reinforcing material is 40wt%, and the particle size of the crushed material is 10mm to 20mm, and the moisture content is less than 0.5wt%.

10. The method for preparing a resin fiber plastic honeycomb composite board by low-temperature melt regeneration according to claim 1, characterized in that, The vacuum degree of the vacuum devolatilization is maintained between -0.06 MPa and -0.09 MPa; the granulation method is a water ring hot cutting process.

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