Preparation method of PC / ABS luggage plate by recycling plastic waste

Abstract

The application belongs to the technical field of non-metal waste processing and polymer material recycling, and discloses a PC / ABS luggage plate preparation method for plastic waste recycling, which comprises waste sorting and cleaning, deep drying, melt grafting modification, blending and granulation, relaxation aging, static field coupling three-roll cooling extrusion molding, constant temperature stress relaxation, surface coating and cutting in sequence. By constructing interface physical entanglement to reduce interface tension, combining multi-epoxy chain extender to repair molecular weight, and applying ultrasonic and thermal three-dimensional coupling field to accelerate residual stress relaxation, the technical problems of plate warping deformation and mechanical strength attenuation caused by micro-interface separation due to thermodynamic incompatibility and residual stress during extrusion molding in PC / ABS waste recycling are solved.

Description

Technical Field

[0001] This invention belongs to the field of non-metallic waste processing and polymer material recycling technology, specifically relating to a method for preparing PC / ABS bag and luggage sheets from recycled plastic waste. Background Technology

[0002] Polycarbonate (PC) and acrylonitrile-butadiene-styrene copolymer (ABS) alloys are widely used in bag manufacturing due to their combined impact resistance and ease of processing. A large amount of PC / ABS waste is generated from cutting scraps and discarded parts during bag production. Conventional recycling involves mechanically crushing and remelting this waste. After multiple thermomechanical processes, the PC / ABS molecular chains undergo irreversible oxidative degradation and chain breakage, resulting in a significant broadening of the molecular weight distribution. PC and ABS are thermodynamically incompatible systems; the mixed waste melt exhibits extremely high interphase tension, making micro-phase separation highly likely at the interface during cooling and solidification. Under external impact, the phase separation interface becomes a stress concentration point and a source of microcracks, leading to a sharp decline in the macroscopic mechanical strength of the finished sheet material.

[0003] Existing technologies employ multilayer co-extrusion coating processes to mask mechanical degradation. However, multilayer co-extrusion only creates interlayer stacking at the macroscopic physical level and cannot repair phase boundary tension defects at the microscopic molecular level. The broken polymer chains within the waste material exhibit a strong orientation effect under the high shear force of the extrusion die. After detaching from the die lip, these high-shear oriented molecular chains rapidly enter the glassy state during the three-roll calendering stage, freezing a large number of high-energy molecular conformations within the sheet. This frozen internal stress spontaneously relaxes to a lower energy state during storage or use, inducing warping and dimensional shrinkage in the finished sheet. Existing technologies lack methods for coupling and controlling the interfacial compatibility process of the waste material molecules with the relaxation process of macroscopic residual stress during molding. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing PC / ABS bag and luggage sheets from recycled plastic waste, which solves the technical problems of microscopic interface separation caused by thermodynamic incompatibility and warping deformation and mechanical strength reduction of the sheets caused by residual stress from extrusion molding in the recycling of PC / ABS waste.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for preparing PC / ABS bag and luggage sheets from recycled plastic waste includes the following steps: Step 1: The original mixed waste material is processed by optical sorting equipment and density separation device to remove impurities, and the output is sorted pure waste material; the density separation device uses a density of 1.18 g / cm³. 3 A liquid calcium chloride aqueous solution was used as the separation medium; Step 2: Use a surfactant aqueous solution to perform high-temperature stirring and cleaning on the sorted pure waste material, and output moist and clean waste material; Step 3: The tunnel-type hot air equipment dehydrates and dries the moist cleaning waste, outputting dried waste with a moisture content of less than 0.015%. Step 4: The twin-screw extruder performs melt grafting and dispersion of the dried waste and modifying agents, outputting modified waste particles; Step 5: The twin-screw extruder performs melt blending and granulation on modified waste granules, fresh polycarbonate, fresh acrylonitrile-butadiene-styrene copolymer, and foaming nucleating agent to output alloy blend granules; Step 6: Perform relaxation aging on the alloy blend granules in a constant temperature and humidity chamber, and output aged and stable granules; Step 7: A single-screw extruder, a multi-stage filter screen, and an electrostatic field coupled three-roll cooling device melt, filter, and cool the aging-stabilized granules to output primary molded sheets; Step 8: The mechanical stretching device and heat treatment oven perform isothermal stress relaxation on the primary formed sheet material, and output the stress-relieved and cured sheet material; Step 9: Grinding and polishing equipment and coating equipment perform physical grinding and UV curing coating on the stress-relief cured board to output the final bag board; Step 10: The CNC cutting machine performs fixed-length cutting on the final bag material and outputs finished parts.

[0006] Furthermore, step 1 specifically includes: the optical sorting equipment uses a broadband near-infrared spectral sensor matrix to lock onto non-target macromolecular polymers, and uses a high-pressure pulsed air jet to remove them; the density separation device uses a density calibrated to 1.18 g / cm³. 3 The liquid calcium chloride aqueous solution performs suspension enrichment on the optically separated materials, and the dewatering screw feeder mechanically squeezes and removes the free water, outputting sorted pure waste material.

[0007] Furthermore, step 2 specifically includes: A surfactant aqueous solution is compounded with a nonionic alkyl polyglycoside surfactant component and a sodium metasilicate detergent component; a jacketed heating reactor system maintains the temperature of the surfactant aqueous solution at a constant 75°C; a double-layer baffled mechanical agitator applies hydrodynamic peeling stress to the surface of the sorted pure waste material at a constant speed of 120 r / min.

[0008] Furthermore, the hydrodynamic stripping stress satisfies the following energy transfer equation: in, The hydrodynamic stripping stress is applied to the boundary layer of the sorted pure waste by a double-layer baffle mechanical agitator. The dynamic viscosity of the surfactant aqueous solution at 75°C; The variable is the infinitesimal velocity difference of the flow field with high turbulent kinetic energy dissipation rate within the jacketed heating reactor system. The spatial normal gradient of the thickness of the fluid boundary layer adhering to the outer surface of the sorted pure waste material.

[0009] Furthermore, step 3 specifically includes: the tunnel-type hot air equipment outputs 90°C hot air to the wet cleaning waste, maintains constant temperature for 180 minutes for forced convection dehydration, reduces the moisture content of the wet cleaning waste to less than 0.015%, and outputs dry waste.

[0010] Furthermore, step 4 specifically includes: the modified additive components include methyl methacrylate-butadiene-styrene copolymer, acrylate elastomers, hindered phenolic antioxidants, phosphite antioxidants, and fluoropolymers; the twin-screw extruder forcibly peels off and disperses the methyl methacrylate-butadiene-styrene copolymer at the microscopic interface between the polycarbonate phase and the acrylonitrile-butadiene-styrene phase, constructing a physically entangled buffer bridge.

[0011] Furthermore, the decrease in interfacial tension follows the physicochemical equation: in, The modified micro-interfacial tension; The initial total surface free energy of the pure polycarbonate phase; The initial total surface free energy of the pure acrylonitrile-butadiene-styrene phase; The dispersive component of the surface free energy of the pure polycarbonate phase; The dispersive component of the surface free energy of the pure acrylonitrile-butadiene-styrene phase; The polar component of the surface free energy of the pure polycarbonate phase; The polar component of the surface free energy of the pure acrylonitrile-butadiene-styrene phase; This refers to the free energy released when methyl methacrylate-butadiene-styrene copolymer undergoes physical bridging and entanglement.

[0012] Furthermore, step 5 specifically includes: accurately weighing the real-time feed mass of fresh polycarbonate and fresh acrylonitrile-butadiene-styrene copolymer based on the pre-calibrated dynamic proportion mass conservation closed-loop verification equation; the dynamic proportion mass conservation closed-loop verification equation is: in, The quality of fresh polycarbonate that needs to be dynamically replenished to the system; The target value for the total mass percentage of polycarbonate in the alloy blend granules determined by the design; The total mass of all materials fed into the flow field during a single blending and granulation process; For the real-time input quality of modified waste particles; This represents the initial mass fraction of polycarbonate contained within the modified waste particles.

[0013] Furthermore, step 6 specifically includes: a constant temperature and humidity chamber provides a stable environment with a constant thermal field of 303.15K and a water vapor pressure of 50% relative humidity, and performs continuous physical relaxation aging on the alloy blend granules for 48 hours, so that the micro-conformation of macromolecules can spatially backtrack to the lowest potential energy degree of freedom, and output age-stabilized granules.

[0014] Furthermore, step 7 specifically includes: applying thermodynamic heat flow and high-frequency mechanical shear friction to a single-screw extruder to transform the age-stabilized granules into a viscous polymer melt; arranging a multi-stage filter group with a 30-mesh coarse filter, a 50-mesh medium filter, and a 70-mesh fine filter in sequence along the flow direction of the viscous polymer melt; and using a coat hanger-type wide-width extrusion die to extrude a wide-width high-temperature cast film using a streamlined damping flow channel distribution topology.

[0015] Furthermore, the electrostatic field coupling three-roller cooling device integrates a high-voltage electrostatic application plate; a 20kV potential difference is established between the high-voltage electrostatic application plate and the first cooling and calendering roller, and the potential difference applies a normal Maxwell electrostatic attraction stress to the wide-width high-temperature cast film, forcing the wide-width high-temperature cast film to adhere to the metal heat-conducting surface of the first cooling and calendering roller without macroscopic air gaps.

[0016] Furthermore, step 8 specifically includes: the mechanical stretching device is equipped with differential servo traction metal roller groups at the front and rear ends to apply a constant physical prestress of 3MPa to the longitudinal geometric section of the primary forming plate; the heat treatment oven maintains a constant thermodynamic temperature field of 80°C by means of a hot air circulation fan; the primary forming plate undergoes 180 minutes of constant temperature forced physical creep relaxation to output a stress-relieved and cured plate.

[0017] Furthermore, the stress relaxation kinetics of the macromolecular chain segments within the primary molded sheet follows the following polymer constitutive equation: in, The residual tensile stress that decays with absolute time during heat treatment; The initial physical freezing stress of the primary formed sheet material before it enters the front boundary of the heat treatment oven; The absolute residence time of the primary formed sheet material in the heat treatment oven; The characteristic viscoelastic relaxation time constant of the polycarbonate-acrylonitrile-butadiene-styrene copolymer alloy system under an 80°C thermal environment.

[0018] Furthermore, step 9 specifically includes: a grinding and polishing equipment equipped with 400-grit silicon carbide sandpaper belt to perform micro-physical friction cutting on the surface of the stress-relief cured board; a leveling coating equipment using a precision-engraved textured metal roller to physically press a 10μm thick liquid film of a mixture of acrylate monomer and photoinitiator onto the surface of the stress-relief cured board; and a high-intensity ultraviolet irradiation darkroom using a 365nm high-frequency photon stream to excite a chain addition polymerization reaction to generate a three-dimensional network polymer protective film.

[0019] Furthermore, step 10 specifically includes: a large vacuum suction cup pneumatic array moves and grabs the final bag material and locks it onto the CNC cutting machine worktable; a polycrystalline diamond hard cutting milling cutter applies cutting force at a spindle speed of 5000 r / min; a high-pressure low-temperature cold air jet instantly removes the thermodynamic heating, preventing thermal melting and caking, and outputs the finished part.

[0020] Furthermore, the modified auxiliary component in step 4 further includes a styrene-acrylate polyepoxy functional group chain extender; the twin-screw extruder utilizes the highly reactive epoxy groups inside the styrene-acrylate polyepoxy functional group chain extender to perform an in-situ ring-opening addition reaction with the terminal hydroxyl and terminal carboxyl groups of polycarbonate undergoing oxidative degradation and chain scission inside the dried waste, constructing covalent bonds to repair the long-chain backbone; the molecular weight topological repair polymerization kinetics of the in-situ ring-opening addition reaction follows the following partial differential equation: in, For absolute time Axial spatial coordinates of twin-screw extruder Instantaneous weight-average molecular weight of the polycarbonate phase; The axial translational velocity of the viscous polymer melt inside the twin-screw extruder; It is the pre-exponential factor for the ring-opening reaction of epoxy; This represents the intrinsic activation energy for the nucleophilic addition reaction between the terminal hydroxyl group and the epoxy group; The molar constant of an ideal gas; coordinates Real-time thermodynamic temperature of a viscous polymer melt; The epoxy equivalent concentration of styrene-acrylate polyepoxy functional chain extender in the local micro-element; The instantaneous molar concentration of active terminal hydroxyl groups generated during polycarbonate degradation and chain scission. This is the initial weight-average molecular weight baseline value before the dried waste material enters the twin-screw extruder.

[0021] Furthermore, in step 8, the differential servo traction metal roller group configured at both ends of the mechanical stretching device has a coaxially integrated piezoelectric ceramic ultrasonic transducer. The piezoelectric ceramic ultrasonic transducer transmits ultrasonic mechanical vibration energy waves with a frequency calibrated to 20kHz simultaneously in the normal and tangential directions to the primary forming plate through the high-rigidity metal shell of the differential servo traction metal roller group. The ultrasonic mechanical vibration energy waves, together with the constant thermodynamic temperature field of 80°C and the constant physical prestress field of 3MPa, constitute a three-dimensional multi-element energy coupling relaxation physical field. The total dissipated power density absorbed by macromolecules per unit volume within the primary forming plate follows the following acoustic-thermal coupling energy equation: in, The total dissipated power density absorbed per unit volume of the primary molded sheet and used for macromolecular conformation rearrangement and deentanglement. The initial physical freezing stress of the primary formed sheet material; The instantaneous macroscopic creep strain rate under a constant physical prestress field of 3 MPa; The thermal conductivity of the polycarbonate-acrylonitrile-butadiene-styrene copolymer alloy system; The spatial temperature Laplace operator gradient formed within the primary molded sheet material by a constant thermodynamic temperature field of 80°C. The macroscopic physical density of the primary formed sheet material; The speed of sound propagating longitudinal waves inside the polymer matrix; The angular frequency of the output signal of the piezoelectric ceramic ultrasonic transducer; The initial vibration displacement amplitude at the point where the 20kHz ultrasonic wave enters the boundary layer of the plate; It represents the viscoelastic acoustic attenuation absorption coefficient of the polymer matrix for high-frequency sound waves.

[0022] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes optical sorting and density separation to deeply remove heterogeneous impurities, preventing them from causing degradation and defects during subsequent high-temperature melting. High-temperature surfactant cleaning combined with deep drying reduces the moisture content of the waste to extremely low levels, blocking the hydrolysis and chain-severing reaction of polycarbonate at its source and ensuring the integrity of the macromolecular chains. In a twin-screw extruder, methyl methacrylate-butadiene-styrene copolymer is used as the core modifying agent, forcibly dispersed at the microscopic interface between the polycarbonate and acrylonitrile-butadiene-styrene phases to construct a physically entangled buffer bridge, significantly reducing interfacial tension and solving the macroscopic phase separation and mechanical weakness caused by the thermodynamic incompatibility of the two phases, thus rebuilding the interfacial stress transfer capability. The amount of fresh polycarbonate and fresh acrylonitrile-butadiene-styrene copolymer added is controlled in real time using a dynamic ratio mass conservation closed-loop verification equation, precisely compensating for the performance loss of the waste.

[0023] This invention simultaneously introduces a foaming nucleating agent to form a closed-cell bubble network, effectively passivating stress creasing and absorbing impact energy. The alloy blend granules undergo isothermal and humidity-controlled relaxation aging to release the metastable conformational energy of rapid freezing, providing a thermodynamically stable basis for subsequent molding. During extrusion molding, an electrostatically coupled three-roll cooling device utilizes a high-voltage electrostatic field to generate Maxwellian electrostatic attraction stress, eliminating the air gap thermal resistance between the wide-width high-temperature cast film and the cooling rollers, achieving efficient and uniform heat transfer, significantly reducing extrusion orientation freezing stress, and obtaining a primary molded sheet with excellent flatness. A mechanical stretching device combined with a heat treatment oven applies constant prestress and a thermal field to the primary molded sheet, causing creep and conformational rearrangement of macromolecular chain segments, effectively relaxing residual internal stress and overcoming warping and shrinkage during storage.

[0024] This invention further introduces a styrene-acrylate polyepoxy functional group chain extender, which undergoes an in-situ ring-opening addition reaction with the degraded and broken polycarbonate end groups. This covalently repairs the long-chain backbone and forms a long-branched topology, significantly improving the polycarbonate's weight-average molecular weight and melt elasticity, and fundamentally restoring the product's impact toughness and tensile ductility. In step eight, a piezoelectric ceramic ultrasonic transducer is integrated inside the differential servo traction metal roller assembly. High-frequency ultrasonic mechanical vibration energy waves are transmitted to the sheet material, forming a three-dimensional multi-element energy coupling relaxation physical field with a constant thermal field and prestress. This accelerates the deentanglement of macromolecules in the core layer, significantly shortening stress relaxation time and reducing macroscopic thermal shrinkage and internal residual birefringence, achieving ultimate dimensional stability. Finally, after physical polishing, UV-cured coating, and precision cutting, a high-hardness, scratch-resistant, and geometrically accurate finished bag component is obtained. The entire method organically integrates waste purification, interface physical repair, molecular weight chemical recombination, and multi-physics field stress regulation, resulting in substantial improvements in the mechanical strength, dimensional accuracy, and processing efficiency of PC / ABS waste products. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a flowchart of the method of the present invention.

[0027] Figure 2 The following is a sub-flowchart illustrating the molecular weight repair process using styrene-acrylate polyepoxy functional group chain extenders introduced in this invention.

[0028] Figure 3The flowchart for the three-dimensional multi-element energy coupling stress relaxation using a piezoelectric ceramic ultrasonic transducer introduced in this invention is shown below.

[0029] Figure 4 This is one of the system operation interface diagrams when the method described in this invention is implemented.

[0030] Figure 5 This is the second diagram of the system operation interface when the method described in this invention is implemented. Detailed Implementation

[0031] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0032] The following is in conjunction with the appendix Figures 2-3 The embodiments of the present invention will be described in detail below.

[0033] Example 1: This example provides a method for preparing alloy bag sheet materials from recycled PC / ABS waste. The original mixed waste originates from the cutting edge scraps and end-of-life recycled parts in bag manufacturing. Its physical composition is highly dispersed, containing metal fastener fragments, non-target thermoplastic polymers such as polyvinyl chloride and polypropylene, and inorganic particulate impurities. Directly introducing the unpurified original mixed waste into the subsequent high-temperature melting process will cause interphase cross-linking, carbonization, and black spot deterioration. Impurities are first removed at the molecular vibration level.

[0034] In practice, the raw mixed waste is fed into the detection field of the optical sorting equipment in a single-layer, flat manner by a vibrating feeder. The optical sorting equipment is equipped with a broadband near-infrared spectral sensor matrix, emitting a detection beam with wavelengths covering 400 nm to 2500 nm. When the detection beam irradiates the outer surface of the raw mixed waste, the photon energy resonates with the chemical bonds inside the polymer, causing molecular vibrational overtones and combination absorption. The carbonate groups on the PC macromolecular chain segments, as well as the cyano groups and benzene ring functional groups inside the ABS molecules, exhibit characteristic high-intensity absorption peaks in specific near-infrared bands (e.g., the 1650 nm to 1750 nm range). The optical sorting equipment has a built-in digital signal processor that continuously acquires the energy distribution signal of the unabsorbed diffuse reflectance spectrum, converts it into a continuous mathematical fitting function, and compares it with a pre-stored polymer infrared spectral database through differential calculations.

[0035] When the spectral difference threshold of a piece of raw mixed waste deviates from the target reference range of PC or ABS, the optical sorting equipment determines it to be a heterogeneous macromolecular impurity. This instantaneously triggers the microsecond-level high-frequency pneumatic solenoid valve at the bottom, releasing a high-pressure pulsed air jet. The high-pressure pulsed air jet provides instantaneous momentum, blowing away non-target macromolecular polymers and discolored impurities from the free-fall flow of the raw mixed waste, thus completing spectral-level purification.

[0036] The optically sorted material is introduced into a density separator. The density separator is calibrated to a charge density of 1.18 g / cm³. 3 A liquid calcium chloride aqueous solution. The physical density of PC is normally distributed at 1.14 g / cm³. 3 Up to 1.15 g / cm 3 Within this range, the physical density of ABS is typically distributed at 1.05 g / cm³. 3 Up to 1.08 g / cm 3 Both were below 1.18 g / cm³. 3 The liquid phase boundary value. High-density metallic impurities and some heavy halogen-containing flame-retardant engineering plastics have a density greater than 1.18 g / cm³. 3 The low-density polyolefin fragments settle; they float on the liquid surface; and the target phase components form a stable suspended enrichment layer in a specific liquid depth region. The density separation device is designed with an overflow pipe on the side wall to continuously collect the suspended enrichment layer material.

[0037] The collected material is fed into a dewatering screw conveyor, where the mechanical extrusion stress generated by the rotation of the variable-pitch metal screw blades peels off the free liquid calcium chloride aqueous solution adhering to the material surface. After dual purification by fluid dynamics and gravity field, the sorted and purified waste is output. This physically blocks the reaction pathway of heterogeneous macromolecules in the molten state that promotes degradation and chain scission.

[0038] The surface of the sorted purified waste material is covered with a large number of exogenous organic oil particles and micron-sized silicate dust adsorbed by electrostatics. High-temperature stirring cleaning uses a high-concentration surfactant aqueous solution to disrupt the van der Waals forces between the contaminants and the surface of the sorted purified waste material.

[0039] The surfactant aqueous solution is formulated with a nonionic alkyl polyglycoside surfactant component and a sodium metasilicate detergent component. The sodium metasilicate detergent component hydrolyzes in water, releasing hydroxide ions and maintaining the pH of the aqueous solution stable within the range of 9.5 to 10.5, thus creating suitable conditions for the saponification of animal and vegetable oils, degrading water-insoluble macromolecular lipids into water-soluble sodium fatty acid salts and glycerol. The nonionic alkyl polyglycoside surfactant molecular chain has an asymmetric polar topology: one end is a hydrophilic polyhydroxyl polar head, and the other end is a lipophilic long carbon chain hydrophobic tail. During the washing process, driven by the principle of "like dissolves like," the hydrophobic tail is directionally inserted into the organic oil layer on the surface of the sorted and purified waste; the hydrophilic polyhydroxyl polar head extends towards the bulk aqueous phase. A large number of surfactant molecules three-dimensionally surround the organic oil particles, forming a nanoscale spatial micelle structure.

[0040] High-temperature stirring and cleaning is carried out within a closed jacketed heating reactor system. This system precisely maintains the temperature of the surfactant aqueous solution at 75°C through heat transfer oil circulation, stimulating the Brownian motion of the organic oil macromolecular chains and reducing the internal friction viscosity between fluid layers. A double-layered baffled mechanical agitator forcibly cuts the fluid at a constant speed of 120 r / min, generating a flow field with a high turbulent kinetic energy dissipation rate, applying continuous and intense hydrodynamic stripping stress to the solid surface of the sorted purified waste. This stripping stress follows the aforementioned energy transfer equation.

[0041] Nanoscale micelles encapsulating organic oil particles are detached from the solid phase surface of sorted purified waste and dispersed into the bulk aqueous system under the synergistic effect of a hydrodynamic exfoliation stress field and a 75°C thermodynamic energy field. After exfoliation, the fluid containing the micelles is discharged. The solid material enters a porous drum for countercurrent rinsing with clean water, and deionized water is introduced to perform a three-stage forced concentration gradient diffusion displacement to wash away residual surfactant macromolecules adhering to the material surface. After sufficient displacement, a moistened and cleaned waste is output. The solid phase surface free energy of the moistened and cleaned waste recovers to the level of pure polymer, ensuring that the subsequent melt grafting reaction of modifying agents in the extruder can proceed smoothly.

[0042] Moist cleaning waste carries water molecules in two different thermodynamic energy states: Free water molecules adhere to the surface and macroscopic pores via capillary forces and surface tension; bound water molecules are anchored in the free volume of the amorphous regions of PC and ABS through van der Waals forces and hydrogen bonds. The PC backbone contains polar carbonate groups; trace amounts of bound water molecules can induce irreversible hydrolysis and chain breakage of these carbonate groups under subsequent high-temperature melting and shearing conditions, leading to a sharp decrease in the weight-average molecular weight of PC and a loss of macroscopic impact resistance. A thermodynamic mass and heat transfer gradient field is established to strip away both types of water molecules.

[0043] Moist cleaning waste is continuously conveyed into the tunnel-type hot air equipment. The equipment creates a forced convection thermal field from bottom to top, and the heated tube array outputs a high-speed, dry, hot airflow of 90°C into the inner cavity. This 90°C dry, hot airflow creates a temperature gradient and a water vapor partial pressure gradient on the porous surface of the moist cleaning waste: the temperature gradient forces heat to move from the surface inwards via Fourier conduction; the water vapor partial pressure gradient forces water molecules to undergo reverse Fick mass diffusion from the interior to the exterior boundary layer. The internal diffusion flux of water follows Fick's first law, leading to the introduction of the water diffusion flux equation: in, The macroscopic mass transfer flux for the diffusion of water molecules from the interior of wet cleaning waste to the outside; The effective physical diffusion coefficient of water molecules in the porous PC and ABS matrix; The variation in local water molecule concentration within the micro-space of the wet cleaning waste; This represents the spatial normal depth gradient for water molecules migrating from the core to the outer boundary layer.

[0044] Free water molecules overcome the surface tension of the liquid phase and vaporize under thermodynamic driving force at 90°C; bound water molecules absorb activation energy, break free from the hydrogen bond anchoring of polar groups in the amorphous region, gradually migrate to the surface, and are discharged into the mainstream gas phase field. After 180 minutes of isothermal forced convection dehydration, both free and bound water molecules are completely stripped and extracted from the system by the dehumidification fan. The moisture content of the wet cleaning waste is reduced to below 0.015%, and dried waste is output after meeting the target. This blocks the hydrolysis reaction path in subsequent high-temperature extrusion processing, preserving an anhydrous thermodynamic environment for the integrity of the polymer chain segments.

[0045] Due to significant differences in polarity and solubility parameters, the PC and ABS phases within the dried waste exhibit substantial interfacial tension in the blended melt. This tension easily leads to phase separation during cooling and solidification, forming a weak physical interface lacking stress transfer capability. The dried waste is metered by a loss-in-weight feeder and simultaneously fed into the forced conveying section of a twin-screw extruder along with the modifying agents. The modifying agent composition includes MBS, acrylate elastomers, hindered phenolic antioxidants, phosphite antioxidants, and fluoropolymers. The twin-screw extruder screw configuration integrates multiple sets of staggered kneading blocks and toothed mixing elements, powerfully driving the material across the melting temperature into a viscous flow state.

[0046] MBS exhibits a core-shell microstructure, with the core layer consisting of flexible polybutadiene rubber segments and the shell layer consisting of rigid polymethyl methacrylate segments.

[0047] The shell layer of polymethyl methacrylate (MBS) segments contains a large number of polar ester groups, exhibiting high dipole interaction and thermodynamic compatibility with the PC phase in the dried waste. Simultaneously, the polarity of the shell layer is similar to that of the styrene-acrylonitrile continuous phase within the ABS phase. The toothed mixing element of the twin-screw extruder outputs high normal shear and tensile stresses, forcibly peeling and tearing the aggregated MBS, uniformly dispersing it at the microscopic interface between the PC and ABS phases. The core layer of flexible polybutadiene segments extends in situ at the two-phase interface, constructing a physically entangled buffer bridge across the phase interface. The decrease in microscopic interfacial tension follows the aforementioned physicochemical equations.

[0048] MBS releases free energy through physical bridging at the interface, offsetting the initial surface free energy and forcing the final microscopic interfacial tension to drop to an extremely low level. The thickness of the two-phase interface expands at the nanoscale, the relative slip resistance at the phase interface increases exponentially, and the microscopic stress transmission channels are opened.

[0049] Under the high shear rates of twin-screw extruders, the large molecular segments of dried waste are prone to frictional heat generation and mechanical degradation. Fluoropolymers in the modified additive components possess low surface energy; their molecular chains spontaneously migrate and accumulate at the boundary layer where the blended melt contacts the extruder's metal inner wall under high-temperature viscous flow conditions. This spreads to form an extremely thin dynamic extreme-pressure lubricating film, transforming the dry friction between the large molecular melt and the metal inner wall into internal friction, thus inhibiting excessive shear breakage of the large molecular segments. Hindered phenolic antioxidants provide active hydrogen atoms to terminate the chain oxidation reaction, while phosphite antioxidants reduce harmful hydrogen peroxides to stable alcohol compounds. Through these multiple protections, the twin-screw extruder die head outputs modified waste particles with physically repaired internal microscopic compatibility interfaces via a water-cooled pelletizing system.

[0050] Although the modified waste granules repaired the microscopic physical compatibility interface, their macromolecular chain length distribution was biased towards the low molecular weight range, making them unable to independently support the mechanical requirements of subsequent wide-width luggage panels. Modified waste granules, fresh PC, fresh ABS, and a foaming nucleating agent were jointly introduced into the blending and granulation process. A microcomputer-controlled multi-component loss-in-weight feeding system, based on a dynamic proportioning mass conservation closed-loop verification equation, adjusted and locked the real-time feeding mass of fresh PC and fresh ABS. The dynamic proportioning mass conservation closed-loop verification equation is shown above. Fresh PC introduces an ultra-high molecular weight main chain rigid framework, improving the tensile yield strength and heat distortion temperature of the alloy blend granules; fresh ABS supplements the unoxidized butadiene rubber phase and the highly fluid flexible matrix in the amorphous region, repairing the material's low-temperature impact toughness.

[0051] The foaming nucleating agent selected is sodium benzoate powder with a particle size distribution concentrated in the range of 2μm to 5μm. The twin-screw extruder barrel for blending is set with multiple heating temperature stages, ranging from 210°C to 250°C. In the viscous flow blending system, deep three-dimensional interweaving of macromolecular chain segments occurs in the strong mixing region. The sodium benzoate powder is uniformly dispersed in the melt as rigid microparticles, forming a massive number of heterogeneous physical nucleation centers. Trace amounts of volatile gas molecules entrained within the polymer raw material and small molecules precipitated during high-temperature mixing spontaneously diffuse and accumulate towards the nucleation center interface under the coupled drive of concentration gradient and pressure fluctuations, expanding and developing a micron-scale closed-cell bubble network with a scale of 5μm to 15μm around the surface of the sodium benzoate powder.

[0052] Micron-level closed-cell bubble networks act as damping and passivation agents. When the product is subjected to external dynamic impact and stress crazes occur, the craze tips extend to the bubble boundaries, forcibly compressing the bubbles from a spherical shape into a flattened ellipsoid. This deformation process absorbs and dissipates a large amount of impact mechanical energy. The geometric passivation effect of the bubble walls disperses the highly concentrated stress field, blocking the dynamic path of stress craze propagation into destructive cracks. After the blended macromolecular melt undergoes sufficient shear homogenization and three-dimensional bubble shaping, it is rapidly cooled and solidified by an underwater pelletizer, locking in the three-dimensional microscopic dispersion phase of the multiphase macromolecules and outputting alloy blended pellets.

[0053] During the rapid cooling process of extrusion pelletizing, the large molecular chains inside the alloy blend granules undergo a large temperature gradient and cannot retract to the lowest potential energy random coil form through thermal motion. Instead, they are forcibly frozen in a highly extended, non-equilibrium, high-energy conformation. If the alloy blend granules in this state are directly subjected to subsequent wide-width sheet secondary casting extrusion, the secondary orientation stress during the extrusion process will be linearly superimposed with the original freezing stress of the material, causing severe dimensional shrinkage and warping.

[0054] The constant temperature and humidity chamber provides a stable environment with a constant thermal field of 303.15K and a water vapor pressure of 50% relative humidity for isothermal relaxation aging of the alloy blend granules. The thermodynamic energy of 303.15K is slightly higher than the reference temperature for the secondary relaxation (β-relaxation) transformation of the flexible polybutadiene segments in MBS. The frozen PC side groups and flexible short polybutadiene segments within the alloy blend granules continuously acquire microscopic thermal activation energy in the constant thermal field, overcoming the conformational transformation barrier and undergoing local cranking rotation and microscopic conformational rearrangement. These movements cause the macroscopic residual stress stored within the molecular segments to dissipate to the environmental system. The 50% relative humidity water vapor pressure environment provides moderately plasticized water molecules to the micropores on the surface of the macromolecular matrix, further reducing the steric hindrance of the chain segment conformational rearrangement.

[0055] After 48 hours of continuous physical relaxation aging, the microstructure of the macromolecules inside the alloy blend granules reverts from a metastable high-energy state to the lowest global potential energy degree of freedom, completing local stress homogenization and outputting age-stable granules. This eliminates the potential source of stress concentration.

[0056] The aged and stabilized granules are continuously fed into the feed throat of the single-screw extruder by gravity. The single-screw extruder features a gradually varying screw depth and a specific physical compression ratio. It relies on external resistance heating of the barrel to transfer thermodynamic heat flow, which, combined with the high-frequency mechanical shearing friction applied to the granules by the internal rotating screw, drives the material through the glassy and elastic states, transforming it into a viscous polymer melt. The screw speed is locked at 45 r / min to prevent excessive shear rate from causing excessive shear stress that could cut off long segments of the PC main chain.

[0057] The viscous polymer melt is pushed to the inlet of the die head, where a multi-stage filter group is sealed and encapsulated. Along the flow direction, there are a 30-mesh coarse metal filter, a 50-mesh medium metal filter, and a 70-mesh fine metal filter. The physical pore size is used to intercept the micron-sized inorganic impurity particles and incompletely thermoplasticized cross-linked polymer gel particles trapped inside the melt.

[0058] The filtered viscous polymer melt enters a coat hanger-type wide extrusion die. The inner cavity of the die has a streamlined damping flow channel distribution, which forces the transverse and longitudinal flow fields to establish a pressure balance, ensuring that the melt is stably extruded along a uniform velocity field and thickness field at the die lip gap, forming a wide high-temperature cast film.

[0059] At the instant the wide-width, high-temperature cast film detaches from the die lip, the macromolecular main chain segments undergo a high degree of axial orientation due to the extrusion convergence and stretching field. The cast film then adheres to the electrostatically coupled three-roll cooling device. The device integrates high-voltage electrostatic application plates, which excite local corona discharge in the air dielectric, injecting a large number of free electrons and negative ions into the boundary layer of the upper surface of the cast film. The lower surface of the cast film is in close contact with the grounded first cooling and calendering roller, establishing a 20kV potential difference between the upper and lower surfaces of the cast film. This potential difference induces Maxwellian electrostatic attraction stress within the normal thickness space of the cast film, and the calculation equation is defined as follows: in, The normal Maxwell electrostatic attraction stress applied to a wide-width high-temperature cast film; It is the vacuum permittivity; The relative permittivity of the wide-width high-temperature cast film body; The potential difference is 20kV. This refers to the normal thickness of the wide-width high-temperature cast film.

[0060] The normal Maxwell electrostatic attraction stress uniformly and seamlessly presses a wide-width, high-temperature cast film onto the thermally conductive metal surface of the first cooling and calendering roller, eliminating the thermal resistance layer caused by air gaps. This facilitates the transfer of the high enthalpy of fusion and sensible heat within the cast film to the circulating cooling medium within the roller via maximum Fourier heat transfer flux. The cast film sequentially wraps around the first cooling and calendering roller, the second cooling and shaping roller, and the third cooling and shaping roller, causing its body temperature to plummet from 240°C to 50°C. This achieves thermodynamic freezing of the microscopic movement of the macromolecular chain segments, resulting in phase change solidification and transformation into a primary molded sheet. The electrostatically coupled three-roller cooling device outputs a primary molded sheet with extremely high flatness.

[0061] The primary molded sheet contains a large number of highly oriented macromolecular chain segments and residual tensile stress, which are deeply frozen inside. Under the influence of slight thermal fluctuations during storage at room temperature, this residual tensile stress spontaneously causes irreversible macroscopic strain retraction, leading to sheet warping. The primary molded sheet is continuously drawn into a mechanical stretching device. Differential servo traction metal roller sets are configured at the front and rear ends of the device. By controlling the difference in linear speed between the front and rear rollers, a constant physical prestress of 3 MPa is applied to the longitudinal geometric cross-section of the sheet. Under this pre-stretched state, the sheet simultaneously passes through a heat treatment oven. Inside the oven, a constant thermodynamic temperature field of 80°C is maintained by a hot air circulation fan. 80°C crosses the glass transition reference temperature of the butadiene rubber phase in ABS and simultaneously provides the sub-glass transition thermal activation energy for the rigid main chain segments of PC.

[0062] Driven by both 3MPa longitudinal prestress and a constant thermal field of 80°C, the macromolecular chains inside the primary molded sheet undergo physical creep and microscopic conformational rearrangement kinetics. High-energy oriented conformational segments undergo intense Brownian motion to untangle their physical entanglements and seek the lowest potential energy distribution point along the direction of the tensile force field. The stress relaxation kinetic evolution follows the aforementioned polymer constitutive equations.

[0063] After 180 minutes of isothermal forced physical creep relaxation, the macroscopic stress parameters inside the primary molded sheet approached zero. The microscopic free volume inside the polymer was densified. The sheet was continuously removed from the heat treatment oven and the 3MPa prestress was removed. It was then cooled to room temperature by ambient cold air and output as a stress-relieved cured sheet. The stress-relieved cured sheet achieved macroscopic physical geometric dimensional stability at the thermodynamic equilibrium level.

[0064] The stress-relief cured sheet's upper and lower surfaces are affected by microscopic scratches on the extrusion die lip and roughness transfer from the cooling roller surface, resulting in micron-level die lip drag scratches and minute gloss troughs. The sheet is fed into a grinding and polishing equipment via conveyor belt. The equipment is equipped with 400-grit silicon carbide abrasive belts, which apply uniform contact pressure to the surface of the stress-relief cured sheet at high linear speed, performing microscopic physical friction cutting to peel off the outermost heterogeneous micro-protrusion structure and reduce the surface roughness to 0.5μm. Subsequent stations use cotton cloth wheels and nano-alumina polishing paste to perform flexible physical rheological polishing on the sheet surface, eliminating the micron-level brittle scratches left by the previous silicon carbide abrasive particles.

[0065] After polishing and stress-relief curing, the sheet material enters a leveling coating device. The device uses precision-engraved textured metal rollers to physically coat the sheet surface with a 10μm thick liquid film of a mixture of acrylate monomers and a photoinitiator. The acrylate monomer molecules are rich in double-bonded carbon-carbon functional groups.

[0066] After coating, the board is continuously passed through a high-intensity ultraviolet irradiation dark chamber, where a built-in light-emitting diode array emits a high-frequency photon energy stream with a peak wavelength of 365nm. The photoinitiator in the liquid mixed film absorbs the 365nm photon energy, causing homolytic cleavage of the weak covalent bonds within the initiator molecules, instantly generating a large number of primary high-energy free radicals. These primary free radicals attack the π bonds in the carbon-carbon functional groups of the acrylate monomer double bonds, initiating a chain addition polymerization reaction. Within milliseconds, the liquid acrylate monomers crosslink and solidify into a three-dimensional network polymer protective film. The film is anchored to the solid-phase interface of the stress-relieved board through secondary intermolecular forces, isolating the board's polymer matrix from external atmospheric oxygen and short-wave ultraviolet radiation, while simultaneously imparting scratch resistance to the board surface exceeding the 3H pencil hardness test level. After optical crosslinking and surface encapsulation, the final bag material is produced.

[0067] Finally, the bag material is grasped and positioned on the CNC cutting machine's worktable by a large vacuum suction cup pneumatic array. The suction cup array evacuates the air gap at the bottom of the material, creating a negative pressure environment to lock the material onto the worktable. The CNC cutting machine reads the pre-input digital program for the geometric dimensions of the bag shell's two-dimensional plane. A servo motor drives a polycrystalline diamond cutting cutter at a spindle speed of 5000 rpm to cut into the thickness interface of the material, applying high shear cutting force to break the polymer backbone and complete physical separation. The thermodynamic temperature rise generated by friction is instantly carried away by a high-pressure, low-temperature jet of cold air, preventing the cut edges from exceeding the melting temperature threshold and causing smudging. The material is precisely divided into standard-sized finished components according to the digital program instructions and output to the final assembly line.

[0068] To facilitate a better understanding of the present invention by those skilled in the art, the present invention will be further described below with reference to specific implementation examples; Material balance calculations were performed on 1000kg of raw mixed waste from a single batch.

[0069] 1000 kg of raw mixed waste material was processed by optical sorting equipment and density separation device to remove 50 kg of heterogeneous impurities such as polyvinyl chloride, 10 kg of metallic impurities were removed by gravity sedimentation, and 15 kg of light polypropylene impurities were removed by liquid surface suspension, resulting in 925 kg of sorted pure waste material. This 925 kg of pure waste material was then physically stripped in a jacketed heated reactor system using a surfactant aqueous solution to wash away 5 kg of organic grease impurities, yielding 920 kg of moist clean waste material. This 920 kg of moist clean waste material was then dehydrated in a tunnel-type hot air device using a 90°C dry hot air stream, removing 20 kg of moisture, resulting in 900 kg of dry waste material with a moisture content of less than 0.015%. This 900 kg of dry waste material, combined with 45 kg of composite modifying agent, was then extruded through a twin-screw extruder to produce 945 kg of modified waste material particles. During the modification process, the interfacial tension decreased according to the aforementioned physicochemical equation.

[0070] Substitute 945 kg of modified waste particles into the dynamic proportioning mass conservation closed-loop verification equation. Assume the total mass of a single operation... For 1500kg, alloy target The value is 0.7, within the modified waste particles. It is 0.6. According to the equation kg, the system was replenished with 483 kg of fresh polycarbonate, and the remaining 72 kg was fresh acrylonitrile-butadiene-styrene copolymer and foaming nucleating agent.

[0071] The blending and granulation process yields 1500 kg of alloy blended granules. These 1500 kg granules are then subjected to a 303.15 K constant temperature and humidity chamber for heat treatment to release high-energy stress, resulting in 1500 kg of age-stabilized granules. This 1500 kg age-stabilized granules are extruded using a single-screw extruder and an electrostatically coupled three-roll cooling device. A 20 kV potential difference provides Maxwellian attraction stress, yielding 1500 kg of wide-width primary molded sheets. The primary molded sheets undergo 3 MPa tensile prestressing and baking at 80°C, causing residual stress to decrease exponentially. After cooling, stress-relieved cured sheets are produced. These stress-relieved cured sheets are then subjected to silicon carbide cutting and 365 nm photo-initiated free radical polymerization, with a 10 μm protective film covering the surface, resulting in the final bag / bag sheet material. Finally, the final bag / bag sheet material is CNC-cut to produce dimensionally locked finished components.

[0072] Example 2: Based on Example 1, the density separation operation in step 1 is further specified. The density separation device uses a density calibration of 1.18 g / cm³. 3 A liquid calcium chloride aqueous solution was used to perform suspension enrichment of the optically separated materials. The density calibration of the liquid calcium chloride aqueous solution was performed using a precision densitometer under constant temperature conditions of 20°C to ensure the stability and accuracy of the separation interface.

[0073] Example 3: The difference from Example 1 is that specific parameters are defined for the drying operation in step 3. A tunnel-type hot air device outputs 90°C hot air to the moist clean waste and maintains a constant temperature for 180 minutes for forced convection dehydration. The 180-minute duration is calculated using the Fick diffusion kinetics model of bound moisture within the material, serving as the minimum process window to ensure that the moisture content is reduced to below 0.015%.

[0074] Example 4: Based on Example 1, the application scenarios of the dynamic proportion mass conservation closed-loop verification equation in step 5 are explained in detail.

[0075] When the system detects the initial mass fraction of polycarbonate in the modified waste particles When changes occur due to fluctuations in upstream processes, the data processing unit automatically adjusts the data according to the real-time input. and Value, recalculate the required quantity of fresh polycarbonate to be added. This enables real-time closed-loop control of the final composition of alloy blend granules.

[0076] Example 5: Based on Example 1, this example addresses the irreversible damage to the polymer backbone caused by repeated thermomechanical processing of the original mixed waste, as well as the physical bottleneck of low stress relaxation efficiency of thick-walled plates inside the static heat treatment oven. It substantially supplements the twin-screw extruder melt grafting reaction system in step 4 and the stress relaxation physical field in step 8, establishing a path for molecular weight covalent bond repair and accelerated relaxation by a three-dimensional coupling energy field of acoustic, thermo, and mechanical forces.

[0077] The polycarbonate phase contained within the dried waste is susceptible to hydrolysis and thermo-oxidative degradation during its previous life cycle and crushing process, due to the combined effects of trace moisture and high-temperature shear stress. This results in irregular breakage of the long-chain backbone, exposing numerous terminal bisphenol A structures, namely terminal phenolic hydroxyl and carboxyl groups. The geometric length of the macromolecular chains is drastically shortened, reflected in a sharp decrease in macroscopic physical properties, specifically a loss of weight-average molecular weight and impact ductility. Simply relying on MBS (Metal-Based Stress Barrier) to perform interfacial physical bridging can only reduce microscopic interfacial tension and cannot compensate for the loss of intrinsic strength of the polycarbonate phase.

[0078] A styrene-acrylate polyepoxy functional group chain extender was further introduced into the modified additive component. The main chain of this chain extender is a flexible carbon-carbon single-bond skeleton formed by the copolymerization of styrene and acrylate, with high-density epoxy resin functional groups suspended in the side chains. The epoxy equivalent is specified to be in the range of 280 g / eq to 310 g / eq. The dried waste material and the modified additive were fed into a twin-screw extruder. In the high-shear mixing zone of the extruder, the material temperature exceeded 240°C and entered a viscous flow state.

[0079] Styrene-acrylate polyepoxy functional group chain extenders spread three-dimensionally within viscous polymer melts. Highly active side-chain epoxy groups, in Brownian motion, contact the terminal phenolic hydroxyl or carboxyl groups generated from polycarbonate chain scission, overcoming the activation energy barrier. Due to ring strain, the epoxy three-membered ring undergoes an asymmetric ring-opening isomerization reaction. The oxygen atom on the epoxy group combines with the active hydrogen atom on the polycarbonate terminal group to form a secondary alcohol structure. The oxygen anion or carboxylate anion of the polycarbonate chain scission residues performs a nucleophilic attack on the carbocation after ring opening, generating covalent ether or covalent ester bonds. Two or more low-molecular-weight polycarbonate chain fragments are thus connected into high-molecular-weight long chains by the styrene-acrylate polyepoxy functional group chain extender as chemical linking nodes. Due to the topological properties of the polyepoxy functional groups, some linear long chains further evolve into star-shaped or dendritic macromolecular topologies with long branches. The molecular weight topology repair polymerization kinetics are characterized by a combined computational fluid dynamics and reaction kinetics mathematical model. The evolution equations are locked as follows: The left side of the equation characterizes the effects of spatial convection and time accumulation on molecular weight growth, while the right side reveals the nonlinear control of the reaction rate by Arrhenius's thermodynamic law and the molar concentration of reactants. To match the residence time requirements of in-situ ring-opening addition reactions, the aspect ratio of the twin-screw extruder was increased to 48:1, and three sets of large-lead reverse kneading block elements were added to the middle and rear sections, forcing the viscous polymer melt to form local axial backflow in a high-temperature, high-shear field. The residence time of the melt in the extruder was forcibly extended to 120 s, and the epoxy group conversion rate exceeded 95%. The repaired modified waste particles not only restored the microscopic interfacial compatibility, but also increased the weight-average molecular weight of its bulk polycarbonate phase to near the level of virgin polycarbonate resin.

[0080] For the primary molded sheet output in step 7, with a geometric thickness ranging from 2.5mm to 4.0mm, the PC / ABS alloy system possesses an extremely low intrinsic thermal conductivity. If relying solely on a constant 80°C thermal field and a constant 3MPa prestress within the heat treatment oven, the Fourier conduction of heat from the sheet surface to the core layer is slow. The macromolecular chains in the core layer lack sufficient activation energy, making it difficult to complete Brownian motion and conformational disentanglement within a finite time. As a result, while the surface stress has relaxed, the core layer still retains high-energy orientation residual stress, making it prone to warping deformation during its service life.

[0081] Inside the high-rigidity metal alloy cavity of the differential servo traction metal roller assembly of the mechanical stretching device, several sets of piezoelectric ceramic ultrasonic transducers are coaxially and equally spaced. The piezoelectric ceramic ultrasonic transducers receive external high-frequency sinusoidal alternating current signals for excitation, and induce high-frequency mechanical deformation of the crystal lattice through the inverse piezoelectric effect. The hard aluminum alloy rollers, after acoustic impedance matching, simultaneously transmit 20kHz ultrasonic mechanical vibration energy waves in both the normal and tangential directions to the tightly bonded primary forming plate.

[0082] High-frequency sound waves of 20kHz induce periodic microscopic compressive and tensile acoustic stress fields within the solid matrix of the primary molded sheet, directly acting on the macromolecular backbone and massive side groups. Due to the viscoelastic damping properties of the polymer material, its loss modulus dissipates irreversibly mechanical energy from high-frequency strain. Part of the ultrasonic mechanical vibration energy is converted into internal energy through molecular chain segment friction, triggering uniform microscopic self-heating. This acoustic self-heating penetrates the limitations of low macroscopic thermal conductivity, enabling the core layer of the sheet to rapidly transition to the sub-glass transition temperature range required for macromolecular conformational rearrangement.

[0083] In addition, the micron-sized closed-cell bubble network introduced by the foaming nucleating agent in step 5 undergoes acoustic cavitation resonance under the driving force of 20kHz ultrasonic alternating sound pressure. The bubble walls alternately expand and contract at high frequency, radiating microscopic shear force and transient local high temperature to the surrounding polymer matrix.

[0084] The ultrasonic mechanical vibration energy wave, the constant thermodynamic temperature field of 80°C, and the constant physical prestress field of 3MPa together constitute a three-dimensional multi-element energy-coupled relaxation physical field. The total relaxation power dissipation density absorbed by macromolecules per unit volume within the primary molded sheet is defined by the acoustic-thermal coupling energy equation: The first two terms in the equation characterize the energy contributions of traditional macroscopic mechanical work and macroscopic heat conduction, while the third term quantifies the high-frequency acoustic energy density injected by the piezoelectric ceramic ultrasonic transducer. The three-dimensional multi-element energy coupling physical field significantly shortens the characteristic viscoelastic relaxation time constant. The primary molded sheet only needs to remain in the heat treatment oven for 45 minutes to bring the macroscopic residual stress parameter close to zero. The stress-relieved cured sheet achieves extremely low residual stress while significantly reducing system space and thermodynamic energy consumption.

[0085] To corroborate the gain of molecular weight topological repair and three-dimensional multi-element energy coupling relaxation physical field, industrial-grade parallel preparation comparison tests were conducted on Example 1 (basic process) and Example 5 (polyepoxy chain extension and ultrasonic field coupling process) under equivalent boundary conditions. The test items included the weight-average molecular weight (MAM) determined by gel permeation chromatography (GPC). The cross frequency of the storage modulus and loss modulus obtained by the rotational rheometer ( The parameters include the macroscopic dimensional shrinkage rate measured by a thermomechanical analyzer (TMA). Relevant parameters are compiled in Tables 1 and 2.

[0086] Table 1. Comparison of molecular weight evolution and interfacial rheological parameters during the extrusion granulation stage; Table 2 Comparison of Macroscopic Mechanical and Dimensional Shrinkage Physical Constants of Final Bag Material Data shows that, in Example 5, after introducing a styrene-acrylate polyepoxy functional group chain extender in step 4, the weight-average molecular weight of PC was restored from 28,500 g / mol at the initial stage of waste to 54,300 g / mol, and the notched impact strength increased from 45.2 kJ / m. 2 Increased to 78.6 kJ / m 2 The material transitioned from a brittle fracture mode to a ductile fracture eigenstate. The rheological crossover frequency decreased to 12.8 rad / s, demonstrating that the in-situ ring-opening addition reaction induced a long-branched topology, endowing the melt with high bulk strength.

[0087] Regarding the introduction of the ultrasonic field in step 8, the birefringence optical path difference data in Table 2 reveals the change in internal stress distribution. In Example 1, relying solely on thermodynamic relaxation, the core layer of the board still retains an optical path difference of 215 nm (corresponding to a region of high residual stress concentration); in Example 5, under the alternating sound pressure of a 20 kHz ultrasonic mechanical vibration energy wave, the free volume of macromolecules in the core layer becomes denser, and the birefringence optical path difference decreases to 12 nm. The final longitudinal thermal shrinkage rate of the bag board is 0.08%.

[0088] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing PC / ABS bag and luggage sheet material from recycled plastic waste, characterized in that, Includes the following steps: Step 1: The original mixed waste is subjected to impurity removal by optical sorting equipment and density separation device, and sorted pure waste is output; liquid calcium chloride aqueous solution is used as the separation medium in the density separation device; Step 2: Use a surfactant aqueous solution to perform high-temperature stirring and cleaning on the sorted pure waste material, and output moist and clean waste material; Step 3: The tunnel-type hot air equipment dehydrates and dries the moist cleaning waste, outputting dried waste with a moisture content of less than 0.015%. Step 4: The twin-screw extruder performs melt grafting and dispersion of the dried waste and modifying agents, outputting modified waste particles; Step 5: The twin-screw extruder performs melt blending and granulation on modified waste granules, fresh polycarbonate, fresh acrylonitrile-butadiene-styrene copolymer, and foaming nucleating agent to output alloy blend granules; Step 6: Perform relaxation aging on the alloy blend granules in a constant temperature and humidity chamber, and output aged and stable granules; Step 7: A single-screw extruder, a multi-stage filter screen, and an electrostatic field coupled three-roll cooling device melt, filter, and cool the aging-stabilized granules to output primary molded sheets; Step 8: The mechanical stretching device and heat treatment oven perform isothermal stress relaxation on the primary formed sheet material, and output the stress-relieved and cured sheet material; Step 9: Grinding and polishing equipment and coating equipment perform physical grinding and UV curing coating on the stress-relief cured board to output the final bag board; Step 10: The CNC cutting machine performs fixed-length cutting on the final bag material and outputs finished parts.

2. The method for preparing PC / ABS bag and luggage sheet from recycled plastic waste according to claim 1, characterized in that, Step 1 specifically includes: the optical sorting equipment uses a broadband near-infrared spectral sensor matrix to locate non-target macromolecular polymers, and uses a high-pressure pulsed air jet to remove them; the density separation device uses a density calibrated to 1.18 g / cm³. 3 The liquid calcium chloride aqueous solution performs suspension enrichment on the optically separated materials, and the dewatering screw feeder mechanically squeezes and removes the free water, outputting sorted pure waste material.

3. The method for preparing PC / ABS bag and luggage sheet from recycled plastic waste according to claim 1, characterized in that, Step 2 specifically includes: A surfactant aqueous solution is compounded with a nonionic alkyl polyglycoside surfactant component and a sodium metasilicate detergent component; a jacketed heating reactor system maintains the temperature of the surfactant aqueous solution at a constant 75°C; a double-layer baffled mechanical agitator applies hydrodynamic peeling stress to the surface of the sorted pure waste material at a constant speed of 120 r / min.

4. The method for preparing PC / ABS bag and luggage sheet material from recycled plastic waste according to claim 3, characterized in that, The hydrodynamic stripping stress satisfies the following energy transfer equation: in, The hydrodynamic stripping stress is applied to the boundary layer of the sorted pure waste by a double-layer baffle mechanical agitator. The dynamic viscosity of the surfactant aqueous solution at 75°C; The variable is the infinitesimal velocity difference of the flow field with high turbulent kinetic energy dissipation rate within the jacketed heating reactor system. The spatial normal gradient of the thickness of the fluid boundary layer adhering to the outer surface of the sorted pure waste material.

5. The method for preparing PC / ABS bag and luggage sheet from recycled plastic waste according to claim 1, characterized in that, Step 3 specifically includes: the tunnel-type hot air equipment outputs 90°C hot air to the wet cleaning waste, maintains constant temperature for 180 minutes for forced convection dehydration, reduces the moisture content of the wet cleaning waste to less than 0.015%, and outputs dry waste.

6. The method for preparing PC / ABS bag and luggage sheet from recycled plastic waste according to claim 1, characterized in that, Step 4 specifically includes: the modified additive components include methyl methacrylate-butadiene-styrene copolymer, acrylate elastomers, hindered phenolic antioxidants, phosphite antioxidants, and fluoropolymers; the twin-screw extruder forcibly peels off and disperses the methyl methacrylate-butadiene-styrene copolymer at the microscopic interface between the polycarbonate phase and the acrylonitrile-butadiene-styrene phase, constructing a physically entangled buffer bridge.

7. The method for preparing PC / ABS bag and luggage sheet material from recycled plastic waste according to claim 6, characterized in that, The decrease in interfacial tension follows the physicochemical equation: in, The modified micro-interfacial tension; The initial total surface free energy of the pure polycarbonate phase; The initial total surface free energy of the pure acrylonitrile-butadiene-styrene phase; The dispersive component of the surface free energy of the pure polycarbonate phase; The dispersive component of the surface free energy of the pure acrylonitrile-butadiene-styrene phase; The polar component of the surface free energy of the pure polycarbonate phase; The polar component of the surface free energy of the pure acrylonitrile-butadiene-styrene phase; This refers to the free energy released when methyl methacrylate-butadiene-styrene copolymers undergo physical bridging and entanglement.

8. The method for preparing PC / ABS bag and luggage sheet from recycled plastic waste according to claim 1, characterized in that, Step 5 specifically includes: accurately weighing the real-time feed mass of fresh polycarbonate and fresh acrylonitrile-butadiene-styrene copolymer based on the pre-calibrated dynamic proportion mass conservation closed-loop verification equation; the dynamic proportion mass conservation closed-loop verification equation is: in, The quality of fresh polycarbonate that needs to be dynamically replenished to the system; The target value for the total mass percentage of polycarbonate in the alloy blend granules determined by the design; The total mass of all materials fed into the flow field during a single blending and granulation process; For the real-time input quality of modified waste particles; This represents the initial mass fraction of polycarbonate contained within the modified waste particles.

9. The method for preparing PC / ABS bag and luggage sheet from recycled plastic waste according to claim 1, characterized in that, Step 6 specifically includes: The constant temperature and humidity chamber provides a stable environment with a constant thermal field of 303.15K and a water vapor pressure of 50% relative humidity, and performs continuous physical relaxation aging on the alloy blend granules for 48 hours, so that the micro-conformation of macromolecules will spatially backtrack to the lowest potential energy degree of freedom, and output the aged and stable granules.

10. The method for preparing PC / ABS bag and luggage sheet from recycled plastic waste according to claim 1, characterized in that, Step 9 specifically includes: a grinding and polishing equipment equipped with 400-grit silicon carbide sandpaper belt to perform micro-physical friction cutting on the surface of the stress-relief cured board; a leveling coating equipment using a precision-engraved textured metal roller to physically press a 10μm thick liquid film of acrylate monomer and photoinitiator onto the surface of the stress-relief cured board; and a high-intensity ultraviolet irradiation darkroom using a 365nm high-frequency photon stream to excite a chain addition polymerization reaction to generate a three-dimensional network polymer protective film.

Images