Recycling process for ASR (automotive shredder residue) into blended plastics

Abstract

Disclosed are methods, compositions, and systems for recycling Automotive Shredder Residue (ASR) and post-consumer mixed polymer waste into specification-controlled thermoplastics and molded articles. In certain embodiments, a metal-reduced feed is density-separated to recover a light plastic fraction that is shredded, air-handled, and friction-cleaned to remove moisture, fines, paper, elastomers, and adhered residues. The cleaned fraction is extruded through a screen- changed melt-filtration zone and vacuum-devolatilized, with condensed vapors collected for environmental treatment. During extrusion, one or more coupling agents selected from organic titanates, zirconates, and aluminates are dosed to reactively compatibilize dissimilar polymers and promote adhesion to fillers. Also disclosed is a compatibilized thermoplastic composition comprising PE / PP blends whose interfacial regions include reaction products of the coupling agents and fillers bearing monomolecular coupling-agent layers, and a system integrating flotation, size-reduction, air handling, friction separation, melt filtration, devolatilization with environmental controls, a vented compounding extruder with feeders, and a downstream subsystem with heated accumulator(s) and selectable outlets to a molding press or pelletizer.

Description

Recycling Process for ASR (Automotive Shredder Residue) into Blended PlasticsPRIOR RELATED APPLICATION DATA

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 705,468, filed October 9, 2024, which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] This application relates to methods and systems for recycling Automotive Shredder Residue (ASR) and post-consumer waste containing polymers such as polyethylene (PE), polypropylene (PP), high-impact polystyrene (HIPS), and aciylonitrile-butadiene-styrene (ABS), as well as mixtures thereof. In particular, the application relates to reactive compatibilization and melt-to-mold processing that convert mixed, contaminated polymer streams into specification- controlled compounded materials and molded articles.BACKGROUND

[0003] Automotive Shredder Residue (ASR) is the byproduct of the vehicle recycling process. ASR consists of a mixture of various materials, including plastics, rubber, metals, and other contaminants. Recovering and recycling valuable polymers such as polyethylene (PE) and polypropylene (PP) from ASR is challenging due to the presence of residual automotive fluids, non-melting contaminants, and the mixture of dissimilar polymers. ASR may also contain styrenics (e.g., HIPS, ABS), engineering resins (e.g., polyamides, polyesters), fillers (e.g., talc, CaCCh, glass), elastomers, and fines originating from upstream size-reduction operations, further complicating separation and melt filtration.

[0004] Traditional methods for recycling ASR polymers involve extensive hot water washing with surfactants to remove contaminants such as oils, glycols, and greases, which makes the process costly and water-intensive. Large volumes of wash water drive up energy use for heating and drying and require wastewater treatment to remove emulsified hydrocarbons and surfactant residues. In addition, physically blended polymers without compatibilization from ASR tend to phase-separate, leading to inferior mechanical properties in the final product. Phase separation canmanifest as delamination, embrittlement after thermal aging, and poor impact resistance due to weak interfacial adhesion between immiscible phases.

[0005] There is a need for an efficient, cost-effective method to recycle ASR without extensive washing, while helping to ensure the physical and chemical integrity of the recovered polymers.SUMMARY

[0006] The application provides a process for recycling ASR or post-consumer waste, particularly focusing on the recovery of polyethylene (PE) and polypropylene (PP) polymers. This process reduces the need for extensive washing by utilizing direct extrusion of ASR containing residual fluids. The process also employs catalytic agents during extrusion and polymer hot-melt screening to remove non-melting contaminants and to prevent phase separation in dissimilar polymer blends, and additives for modification of polymer physical properties, allowing for the production of high- quality, uniform blended plastics. In certain embodiments, the melt stream can be routed directly to heated accumulators and then to compression, injection, or structural-foam presses (“melt-to- mold”), eliminating intermediate pelletizing and associated thermal histories. In one aspect, such a method (i) tolerates residual fluids and fines, (ii) continuously removes VOCs during melt processing, (iii) chemically couples dissimilar polymers and fillers to stabilize morphology, and (iv) feeds a continuous molding operation without pelletizing when desired to avoid polymer degradation due to prior heat or molding history.

[0007] Another aspect includes a method having the following steps: (1) Flotation separation at a liquid density of about 1.00 specific gravity (SG) (1.00 ± 0.02 at 23 °C) to separate the light fractions containing plastics. (2) Shredding the floated material to a target size of about 3 / 8 inch (~ 9.5 mm) with ±30% tolerance. (3) Aspirator and friction separation to remove water, paper, rubber, and light contaminants. (4) Direct extrusion with a screen changer for filtering non-melting contaminants. (5) Degassing and vapor collection or devolatilization to remove residual fluids from ASR, such as oils, glycols, and other automotive fluids. (6) Catalytic modification using organic titanates, zirconates, and aluminates during extrusion to chemically repolymerize dissimilar polymers and improve the properties of the blended plastic. (7) Continuous molding using accumulators tied to injectors to ensure continuous polymer feed and accurate placement of temperature-controlled polymer into the compression molds. (8) Optional, electrostatic and / or secondary sink-float separations and / or optical sorters upstream of extrusion to tunePP / PE / HIPS / ABS ratios and filler level. (9) Optional, additive dosing (antioxidants, stabilizers, nucleators, lubricants, odor adsorbers) under loss-in-weight control to maintain specification targets.

[0008] Another aspect includes a method for recycling Automotive Shredder Residue (ASR) or post-consumer mixed polymer waste that includes receiving a feed comprising polymers and contaminants with metals substantially removed; separating the feed by density to obtain a light plastic fraction at a liquid density of about 1.00 specific gravity and, optionally, at about 1.00-1.20 specific gravity; shredding the light plastic fraction to a target size; removing lightweight and heavier contaminants; extruding the separated material through a screen-changed melt filtration zone to remove non-melting contaminants; devolatilizing the melt under vacuum to remove residual automotive fluids and materials; during extrusion, introducing one or more coupling agents selected from organic titanates, zirconates, and aluminates to reactively compatibilize dissimilar polymers and promote adhesion to fillers, and optionally introducing stabilizers, odor adsorbers, nucleators, lubricants, and fillers; and / or delivering the modified melt as a compounded material to molding equipment or to a pelletizer.

[0009] The degassed polymer can be fed into a secondary vented extruder (single or twin screw) where modifiers, additives, and fillers can be incorporated. The venting in this extruder provides a final “polishing” step to remove any remaining vapors. The modified polymer can be then fed into accumulators (low or high pressure), similar to those used in structural -foam molding machines. These accumulators provide a continuous supply of polymer to the molding process. ASR, being a blend of dissimilar polymers, inherently exhibits reduced physical properties compared to catalytically blended polymers. Physical blends are prone to phase separation over time, leading to product failure. To overcome this, catalytic repolymerization can be employed. Organic titanate, zirconate, or aluminate coupling agents, added during extrusion, copolymerize the different polymers in ASR, creating randomized block copolymer units with improved impact properties, elasticity, and processability (see US Patent No. 4,657,988). In certain embodiments, the vacuum level in one or more vents can be maintained between about 5 and 300 mbar absolute, and the total specific energy input can be controlled to limit thermal degradation while achieving dispersion of additives and fines.

[0010] The titanate, zirconate, and aluminate coupling agents also form a monomolecular layer on fillers present in ASR, enhancing their dispersion and adhesion. The phosphorus moieties in thecoupling agents contribute toward flame retardancy. This bridging effect also binds residual rubber to the polymers, further improving recycling efficiency. This catalyst system can be effective not only for olefinic systems but also for styrenic polymers (HIPS, ABS), and even some engineeringgrade polymers like nylons and polyesters. Reacting olefinic ASR with titanates and metallic hydroxides can create formulations that pass UL-94 flame tests (see US Patents Nos. 4,525,494; 5,753,853; 6,197,135). Polymer modification can include a wide variety of char-enhancing additives such as standard nitrogen / phosphate flame retardants, nanoclays (particularly sepiolitebased), and zinc borate for char-layer stabilization, with diminished smoke and heat release rate (HRR). Admixing ASR with titanates in an extruder can yield ethylene-propylene rubber, useful for increasing the low-temperature flexibility of other polymers (see, US Patent No. 4,657,988). Utilizing multiple accumulators connected via a polymer diverter valve enables continuous extruder operation, even with discontinuous molding processes (compression, injection, structural foam). This maximizes extruder efficiency and molding press time by ensuring a readily available polymer supply. In one embodiment, a three-way heated manifold alternates between two accumulators to maintain constant head pressure at the press.

[0011] Another aspect includes a method that can significantly reduce water use and waste generation, while improving the physical properties of the final molded products by utilizing catalytic repolymerization. Compared with hot-wash processes, the disclosed melt-venting approach reduces reliance on surfactants and dryers, minimizes effluent treatment, and consolidates separation, compounding, and molding into a continuous line.

[0012] Another aspect includes receiving polymer-containing ASR or post-consumer feed with metals substantially removed and separating a light plastic fraction via float media, optionally using water at about 1.00 SG and / or brine at about 1.00-1.10 / 1.20 SG to tune PP / PE versus ABS / HIPS / filled cuts.

[0013] Another aspect includes a flotation module with a density-control loop maintaining fluid density within ±0.02 SG at 23 °C.

[0014] Another aspect includes shredding to about 3 / 8 in (~ 9.5 mm) with ±30% tolerance and removing moisture, fines, paper, and light debris via aspirators / air classification.

[0015] Another aspect includes friction separation (optionally with thermal conditioning at about 150-350 °F) to release elastomers and adhered residues.

[0016] Another aspect includes electrostatic separation to produce PP-rich and PE-rich streams and, in certain cases, styrene-rich streams; optical / NIR / IR sorting or secondary density stages may be substituted or added.

[0017] Another aspect includes extruding through a screen-changed melt-filtration zone (e.g., slide-gate, continuous-belt, bolt-type, laser-screen at about 10-200 mesh) with differential- pressure-triggered indexing.

[0018] Another aspect includes devolatilizing under vacuum (e.g., deep-vac) with staged condensers and routing non-condensables to catalytic or regenerative thermal oxidation as required.

[0019] Another aspect includes dosing coupling agents — organic titanates, zirconates, and aluminates — during extrusion to reactively compatibilize dissimilar polymers and promote filler adhesion, stabilizing morphology across olefinic, styrenic, and selected engineering polymers.

[0020] Another aspect includes additive dosing under loss-in-weight control (stabilizers, odor adsorbers, nucleators, lubricants, fillers, flame-retardants) to meet specification targets.

[0021] Another aspect includes flame-retardant packages such as exfoliated sepiolite nanoclay with zinc borate (targeting at least UL-94 V-2 at 3.2 mm) and / or metallic hydroxides to tailor flame, smoke, and drip performance.

[0022] Another aspect includes accumulator-based melt handling that decouples extruder throughput from press cycles and delivers continuous, metered charges to compression, injection, or structural -foam presses with controlled residence time and outlet static mixing.

[0023] Another aspect includes selective routing via a diverter manifold to molding equipment or to pelletizing (strand-cut or underwater), enabling satellite molding logistics.

[0024] Another aspect includes a compatibilized thermoplastic composition comprising PE / PP blends whose interfacial regions include reaction products of titanate / zirconate / aluminate coupling agents and fillers bearing monomolecular coupling-agent layers, produced via melt filtration and devolatilization.

[0025] Another aspect includes a fire-rated composition variant incorporating sepiolite nanoclay and zinc borate to form stabilized char with diminished smoke and heat-release rate.

[0026] Another aspect includes molded articles formed from the foregoing compositions.

[0027] Another aspect includes an integrated processing system comprising modules for flotation, size reduction, air handling, friction separation, electrostatics, primary extrusion with screenchanger, devolatilization with environmental controls, a secondary vented extruder with feeders, and a downstream subsystem with heated accumulator(s) and a selectable outlet to a molding press or pelletizer.

[0028] Another aspect includes methods that omit extensive hot-water washing and instead sequence separation, shredding / air handling, friction removal of rubber / laminates, melt fdtration and vacuum devolatilization (about 5-300 mbar), reactive compatibilization with titanate / zirconate / aluminate coupling, optional performance additives, and accumulator-fed molding to produce articles.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is a flow diagram illustrating a method and system for processing Automotive Shredder Residue (ASR) material.

[0030] FIG. 2 is a schematic diagram of a compounding and melt-handling system that receives polymer fractions from the electrostatic separator.

[0031] FIG. 3 depicts a method (300) for recycling ASR or post-consumer mixed polymer waste.DEFINITIONS

[0032] The term “post-consumer waste” refers to a type of waste produced by the end consumer of a material stream.

[0033] The term “recycle” refers to processing an item so that its constituent materials can be recovered and reused in the manufacture of new products. When post-consumer waste is converted into raw materials rather than being disposed of as solid waste, the resulting material is referred to as “post-consumer recycled” material.

[0034] The term “flame retardants” means agents that inhibit or delay the combustion of thermoplastics by chemical and physical processes. Flame retardants are additives that are mixed into thermoplastics to make them more resistant to burning by increasing ignition resistance, reducing flame spread, or suppressing smoke and dripping. Common flame retardants include phosphorus-based systems (e.g., phosphates, phosphonates), inorganic systems (e.g., aluminum and magnesium hydroxides), and intumescent systems (e.g., glass-forming additives, zinc borate, and nanoclays), which work through different mechanisms such as forming an insulating char layer or releasing water to cool the material. The choice of flame retardant depends on the specificthermoplastic, application, economic factors, and regulatory compliance. Specific flame retardants include zinc borate, glass-forming agents, and nanoclays.

[0035] The term “impact modifiers” means additives that increase the toughness and durability of thermoplastic materials, particularly at low temperatures. The modifiers, which are elastomeric or rubbery, work by absorbing and dissipating the energy from an impact, which prevents cracks from propagating through the material. These impact modifiers include SEBS (styrene-ethylene- butylene-styrene) and polyolefin elastomers and plastomers, including ethylene-propylene rubbers.

[0036] The term “polymer” means a macromolecular compound prepared by polymerizing monomers of the same or different type. The term “polymer” includes homopolymers, copolymers (including block and random), polymers with three or more monomers, interpolymers, and so on.DETAILED DESCRIPTION

[0037] This application provides methods for processing Automotive Shredder Residue (ASR) or post-consumer waste into high-quality, uniform blended plastics such as polyethylene (PE) and polypropylene (PP). The process includes flotation separation, shredding, direct extrusion, catalytic modification, and continuous molding, all while minimizing environmental impact by reducing water consumption and eliminating the need for extensive washing. Through catalytic repolymerization, the application enhances the physical properties of dissimilar polymer blends recovered from ASR. Unless indicated otherwise, percentages are by weight, temperatures are in °C, and “about” encompasses typical industrial tolerances.

[0038] In specific embodiments, ASR with residual fluids can be directly extruded and molded. Trace amounts of these fluids, often miscible in olefinic resins, do not significantly impact the final product’s properties. Moreover, many residual fluids have boiling points below the melting point of polyethylene and polypropylene. This allows for their volatilization and safe collection using standard extruder vapor-collection techniques during the extrusion process. To accommodate the non-meltable components in ASR, extruders (single or twin screw) are equipped with standard screen changers (slide gate, continuous belt, bolt type, laser screen, etc.). Unwashed ASR requires extensive vapor removal. After passing through the screen changer, the molten polymer is forced through a breaker plate with multiple non-plugging holes. This maximizes the polymer’s surface area, facilitating volatilization. The molten strands then can enter a vacuumchamber positioned above the feed throat of a secondary extruder. In other examples, there can be a single extruder. As the polymer falls into the secondary extruder, volatilized fluids are stripped and evacuated to a collection device for condensation and responsible disposal. FIGs. 1 to 3 show an illustrative process. In certain cases, a vent-stuffer or side-feeder can be used to prevent air entrainment at the vent and to meter regrind, fillers, or odor-adsorbent masterbatches.

[0039] The process can begin with flotation separation, where ASR or post-consumer waste can be introduced into a flotation system. Materials with a specific gravity less than about 1.00 SG (water) or, when brine can be used, about 1.00-1.20 SG or 1.0-1.1 or 1.05 to 1.1 — which typically include plastics like filled olefins (and certain HIPS and ABS fractions) — are separated from denser materials that settle at the bottom. The lighter materials float to the top, allowing for the separation of valuable low-density polymers from unwanted waste. Heavier cuts (e.g., ABS-rich) can be recovered using elevated-density media or secondary sink / float cells.

[0040] Once the lighter fractions have been separated, they are shredded to a particle size of approximately 3 / 8 inch. Tolerances of ±30% can generally be acceptable, depending on the requirements for downstream processing. Shredding optimizes the material for further handling, ensuring uniformity and ease of separation. In one example, shredding the particles to 3 / 8 inch produced better-quality products. Where fines generation is problematic, screens and air sorters may be used to produce cleanly fractured edges that reduce stringers and fuzz.

[0041] The shredded material size, specified as approximately 3 / 8 inch, may vary depending on the specific requirements of the process. This size can range from about 1 / 8 to 1-1 / 2 inches (3-38 mm), providing flexibility based on the type of ASR or consumable waste being processed, as well as the capabilities of the downstream equipment. This range allows for optimized shredding to accommodate different material properties and extruder properties (e.g., diameter), while ensuring that the polymer fractions are appropriately sized for subsequent separation and extrusion steps. The ability to adjust the shred size enhances the efficiency and adaptability of the overall recycling process. Preferred feed for 90 mm to 120 mm extruders can be 6 to 12 mm regrind to balance feed stability and filtration load.

[0042] The shredded material, now containing moisture and lightweight contaminants such as paper or fuzz or foam or fiber, can be then processed to remove these impurities. One method of removing water and light contaminants can be through the use of an aspirator, which effectively separates out moisture and lightweight debris from the shredded polymers. Alternatively, othermethods such as air classifiers or cyclonic separators can be used to achieve similar results by utilizing airflow to separate lighter contaminants based on density and particle size. Where moisture exceeds about 1%, a pre-dryer or heated silo can be employed to avoid vent flooding during extrusion.

[0043] After water and lightweight contaminants have been removed, the material can be further refined through a friction separator. This device uses mechanical agitation to dislodge contaminants that are adhered to the polymers. In some cases, a trommel or rotary screen separator may be used as an alternative to the friction separator, especially when the material can be more prone to sticking to contaminants. These alternatives provide mechanical means of separating materials based on particle size, density, and adhesive properties, ensuring that the polymers are sufficiently cleaned for further processing. Delamination mills can also be used to peel apart coextruded laminates common in automotive trim components.

[0044] In the process, rubber contaminants present in ASR are effectively removed using a friction separator. This device operates by mechanically agitating the material, creating friction that dislodges any rubber particles or residues adhered to the polyethylene (PE) and polypropylene (PP) polymers. The friction separator generates a high-energy environment where the lighter, non- rigid rubber materials separate from the more rigid plastics. This method removes rubber without damaging the valuable polymer fractions, ensuring a cleaner, higher-quality feedstock for further processing and improving performance in subsequent extrusion and molding. Additional rubber removal can be achieved with heated nip-roll capture or electrostatic detachment following preheat.

[0045] Once the polymers have been cleaned, the remaining material, now consisting primarily of PE and PP, can be prepared for direct extrusion. The material can be fed into an extruder — singlescrew or twin-screw — depending on the specific processing requirements. The extruder can be equipped with a screen changer to filter any non-melting contaminants that may still be present. The screen changer can be a slide gate, continuous belt, bolt type, or laser screen, depending on the level of filtration required and the processing conditions. Typical screen-pack equivalents of about 10 to 200 mesh can be used, with differential -pressure monitoring to trigger automatic indexing of continuous belts.

[0046] During extrusion, the material undergoes a degassing process to remove residual automotive fluids such as oils, glycols, greases, and other volatile contaminants. These fluidsvolatilize during extrusion because their boiling points are lower than the melting points of polyethylene and polypropylene. Vapors are collected using standard vapor-collection techniques, then condensed and directed to storage for environmentally responsible disposal or recovery. For enhanced vapor removal, the molten polymer can be directed through a breaker plate with multiple non-plugging holes to maximize surface area for vapor evacuation, followed by a vacuum chamber where additional volatiles are stripped before the melt enters a secondary extruder. In some embodiments, two or more vent sections are employed: a first devolatilization vent immediately after the melting zone and a second deep-vacuum vent after distributive mixing. Condensers may be staged (knock-out pot followed by chilled condenser and carbon polishing filter).

[0047] Referring to FIG. 1, ASR-derived feedstock (100) — preferably a light fraction with metals substantially removed by upstream processing — is received and metered into the line. In certain embodiments, coarse metal separation using magnetic and / or eddy-current devices can be provided at the line infeed to capture fugitive ferrous and non-ferrous particles. The feed passes to a primary water float (110) operated at about 1.00 specific gravity (SG) to float low-density polymers (e.g., PP, or PE) and to sink higher-density contaminants (glass, grit, metal fines, filled foams). When separation of ABS / HIPS or filled PP can be desired, a brine cell at about 1.00 to 1.20 SG or about 1.0 SG selectively sinks those polymers while PP / PE continue to float. Alternatively, in water-limited settings, the line can bypass the initial wet float and employ air-only pre-classification, ballistic separation, and / or cyclonic separation to remove fuzz and paper before any wet step.

[0048] The floated material can be dewatered as needed and shredded (130) to a target nominal size of ~3 / 8 in (~ 10 mm) with allowable variation to match downstream screens. An aspirator / air classifier (140) removes fuzz, paper, and fines; heavier debris such as dirt and filled foam can be rejected to waste. Alternatively, after shredding, a tuned-density cell may be used to split fractions by density windows (e.g., 0.85-1.20 g / mL) to stabilize composition prior to final separation.

[0049] As can be seen, a friction separator (1 0) (with optional preheat) dislodges elastomers and adhered residues; delamination mills can be included for co-extruded laminates. Light rubbery material exits with the light fraction, while denser, filled foams are captured as heavies.

[0050] An electrostatic separator (160) (e.g., tribo-charging with high-tension roll) creates a PP- rich and a PE-rich fraction. For styrenic / heavier cuts, ABS / HIPS may be directed to a separate bin. Alternatively, optical / NIR sorters, color / FTIR sorters, UV sorters, MWIR / SWIR / LWIR sorters, oran additional density stage may be substituted or added to tune PP / PE ratios or to separate filled from unfilled polymers.

[0051] Referring to FIG. 2, a polymer stream enriched in polyethylene (PE) or polypropylene (PP) exits the electrostatic separator and enters a blending system (210). The blending system (200) may include one or more surge bins, gravimetric feeders, a tumble blender, a continuous loss-in- weight blender, or combinations thereof sized to provide a well-mixed, specification-controlled feed. Optionally, separate PE-rich and PP-rich streams are blended under feedback control to achieve a target composition before melt processing. Cameras may be used to identify polymer composition in real time to allow improvement of the blending and properties of the final product.

[0052] The blended feed can be conveyed to a primary extruder (220) where it can be melted and filtered to remove non-melting contaminants (e.g., glass fines, paint chips, residual metals). A screen-changer (slide gate, bolt type, or continuous belt) provides on-line filtration; differential-pressure monitoring may trigger automatic indexing. Representative screen equivalents are about 10-200 mesh, selected according to contamination load and desired surface quality.

[0053] Downstream of the melting and filtration sections, a devolatilization module (230) removes residual automotive fluids and volatile organic compounds (VOCs) such as oils and glycols. One or more vacuum vents (e.g., 5-300 mbar absolute) may be employed, with staged condensers to collect vapors. Condensed vapors and non-condensables are directed to environmental controls (280), which can include a knock-out pot, chilled condenser, activated-carbon polishing unit, and — in certain jurisdictions — regenerative thermal oxidation (RTO) or catalytic oxidation. Condensate can be routed to suitable storage for compliant recycling or disposal.

[0054] The partially compounded melt can be transferred to a secondary vented extruder (or a single extruder or a single vented extruder) with additive feeders (240). Coupling / compatibilizing agents (e.g., organic titanates, zirconates, aluminates), stabilizers (primary / secondary antioxidants, UV packages), odor adsorbers, FR fillers and optional fillers (e.g., talc, CaCCh, glass, nanoclays) are incorporated. Representative use levels include about 0.05-2.0 phr for coupling agents and 0.1-1.0 phr for antioxidant packages, with filler levels tailored (e.g., 1-40 wt %) to application requirements. The extruder may employ distributive and dispersive mixing elements and a second vacuum vent to “polish” residual volatiles.

[0055] Sensors and controls (250) — including on-line near-infrared (NIR) composition measurement and periodic DSC / FTIR checks — may drive closed-loop dosing of additives and coupling agents. Additional process signals (melt pressure, torque, melt index correlations) can be used to maintain rheology and morphology targets within predefined control bands and to record material genealogy.

[0056] The compounded melt can be routed to one or more heated accumulators (260) and a diverter manifold (not shown) for continuous delivery to compression, injection, or structural -foam presses. Accumulator capacity and outlet static mixers provide temperature and composition uniformity, minimize thermal histories, and maximize press uptime by decoupling extruder throughput from intermittent press cycles.

[0057] In another embodiment, the compounded melt can be pelletized (270) — for example, by strand-cut or underwater pelletizing — and supplied as pellets to satellite molders. Downstream equipment may include centrifugal dryers, classifiers, and conveying to silos or bags (272). The pellet path can originate upstream or downstream of the secondary vented extruder, depending on formulation complexity and devolatilization needs.

[0058] Valved bypasses may route melt directly from the primary extruder (220) to accumulators (260) for simple formulations, or from the secondary extruder (240) to pelletizing (270) when remote molding can be preferred. The modules (210, 220, 230, 240, 250, 260, 270, 280) are scalable and may be rearranged without departing from the scope of the system. Compounding and melt handling (optional but preferred for melt-to-mold). A primary extruder with melt filtration (180) and a devolatilization module (184) remove non-melting contaminants and residual automotive fluids (oils, glycols). Condensed vapors are directed to environmental controls (220) (e.g., knock-out pot, chilled condenser, carbon polish, and in some jurisdictions, RTO or catalytic oxidizer). A secondary vented extruder with additive feeders (188) incorporates coupling agents (e.g., titanates / zirconates / aluminates), stabilizers, and optional fillers. Sensors and controls (210) (e.g., MWIR or NIR composition, DSC / FTIR checks) may drive closed-loop dosing.

[0059] In another embodiment, the compounded melt can be pelletized and supplied as pellets to satellite molders.

[0060] To help prevent phase separation in the blended polymers, the process can include catalytic modification. During extrusion, organic titanates or zirconates or aluminates are introduced into the molten polymer. These catalysts induce catalytic repolymerization, converting the dissimilarpolymers into randomized block copolymers that exhibit improved elasticity, impact resistance, and processability. Representative use levels are about 0.05-2.0 phr of titanate / zirconate coupling agent, optionally with aluminates and acid scavengers. Reactive dosing can be synchronized with on-line composition estimates (e.g., NIR, optical, or hyperspectral sensors) to maintain morphology targets.

[0061] In addition to catalytic modification, titanates, zirconates and aluminates improve the dispersion and adhesion of fillers present in ASR. These catalysts create a chemical bridge between the polymers and any residual materials, such as rubber or engineering-grade polymers, allowing efficient recycling of mixed waste streams. This coupling works for olefinic polymers such as PE and PP and for styrenic systems like HIPS and ABS. Other optional additives include sepiolite nanoclays, zinc borate, and metal hydroxides (e.g., Mg(0H)2, Al(OH)s) to tailor flame, smoke, and drip performance.

[0062] The process may further employ exfoliated clays, particularly nanoclays derived from exfoliated sepiolite clays, which are fibrous in nature and act to stabilize the char in fire-retarded polymers. These clays help minimize cracks that can form in a char layer, which could otherwise expose unburned polymer to decomposition forces. The clay may also minimize dripping of unburned polymer.

[0063] There can be a zinc borate synergy in conjunction with nanoclays to form a stable char layer that protects any unbumed polymer, with the zinc borate forming its own glassy layer strengthened by the presence of the nanoclay. Such packages may be tuned to meet UL-94 V-2, V-l, or V-0 classifications depending on article thickness and formulation.

[0064] Once the polymers have been degassed and catalytically modified, and blended with additives as required, they are fed into accumulators that store large volumes of molten polymer, ensuring a consistent supply to the molding process. The accumulators are similar to those used in structural -foam molding machines and allow for continuous extruder operation, maximizing efficiency. The continuous supply ensures that molding presses remain operational without interruption, improving productivity. Accumulator capacity may range from about 5 to 200 kg; in one embodiment, an accumulator-to-press residence time of less than 10 minutes limits thermal aging. Static mixers in accumulator outlets improve temperature and composition homogeneity.

[0065] EP rubber can be purchased as virgin or wide-spec additive or fabricated within the extruder by use of the previously mentioned catalysts to create random or block copolymers viacarbon-carbon bond formation between different polymer types being recycled. Suitable elastomer modifiers include EPM / EPR and EPDM; in-situ formation of ethyl ene-propylene segments can arise from catalytic grafting and trans-reaction among olefinic phases under shear. Different- diameter extruders are optimally fed with raw materials sized to flow within the extruder as per commonly accepted standards. Feed constancy can be enhanced by gravimetric feeders and surge bins with live bottoms.

[0066] The resulting polymer blend can be then molded into finished products, which may include automotive parts, packaging materials, construction components, or flame-retardant products. For certain applications, metallic hydroxides or other flame-retardant additives can be added to meet standards such as UL-94. The process can be adjusted to produce low-temperature olefinic polymers by incorporating ethyl ene-propylene rubber, which enhances flexibility and lowers the ductile-brittle transition point. Large-scale continuous pre-blending of feedstocks and additives (e g., in agitated silos) further minimizes fluctuations in composition and rheology.

[0067] During extrusion and degassing, various volatile organic compounds (VOCs) and other residual automotive fluids may be released as gases. To ensure environmental compliance and minimize emissions, the process may integrate environmental equipment such as scrubbers, filters, condensation systems, and, in some jurisdictions, regenerative thermal oxidizers (RTOs) or catalytic oxidizers downstream of condensers. Continuous monitoring (e.g., total hydrocarbon analyzers) can document compliance.

[0068] Referring to FIG. 3, a method (300) for recycling Automotive Shredder Residue (ASR) or post-consumer mixed polymer waste can be shown. A pre-demetallized feed can be first subjected to density separation (310), for example a water float at about 1.00 specific gravity (SG), to recover a light plastic fraction; in certain embodiments an optional brine float at about 1.00 to 1.20 SG can be employed. The light fraction can be then shredded (320) to a target size and processed to remove lightweight and heavier contaminants (330), such as via aspirating / air classification and friction separation. The cleaned material can be introduced to a primary extruder with a screen-changed melt filtration zone to remove non-melting contaminants, and the resulting melt can be devolatilized under vacuum (350) to strip residual automotive fluids including oils and glycols; condensed vapors are collected and routed for environmental treatment. During extrusion, one or more coupling agents (360) selected from organic titanates, zirconates, and aluminates are dosed to reactively compatibilize dissimilar polymers and promote adhesion to fillers, with optionalimpact modifiers, FR (flame retardant) agents, stabilizers, odor adsorbers, nucleators, lubricants, and fillers added as needed. The modified, compounded melt can be then delivered (370) to molding equipment (372) for melt-to-mold processing, or alternatively discharged to a pelletizer (380) to produce pellets for downstream use.

[0069] Different polymers must be adequately separated to ensure high-quality feedstocks for molding. Polymers in ASR are often intermingled due to co-extrusion in original parts and physical interlocking during size reduction, where one polymer becomes folded over another and mechanically locked together. Mechanical unlocking via attrition or delamination improves subsequent electrostatic or density-based separations.

[0070] Achieving optimal polymer size reduction can be essential. An exemplary 3 / 8-inch particle size can be suitable for regrind. Larger particles do not adequately release intermingled polymers, hindering separation. Smaller particles, while extrudable, tend to produce excessive fines that cause extruder screw slippage and yield loss due to screening. A staged grind with screening limits fines recirculation and balances energy use with liberation efficiency.

[0071] Size-reduction technologies include grinders, shredders, hammermills, and other well- known methods, operated at ambient or cryogenic temperatures depending on the material and application. The chosen method and temperature ensure efficient particle breakdown without damaging polymers or generating excessive yield loss. Blade metallurgy and screen geometry are selected to resist abrasion from residual metals and glass.

[0072] Because ASR contains significant quantities of fine metallic wire, secondary fine-metal separation can be performed after final size reduction to 3 / 8 inch and before extrusion. This additional step minimizes wear on the extruder screw and barrel and reduces the risk of screenpack plugging. Supplemental devices can include high-intensity rare-earth magnets, eddy-current separators for non-ferrous fines, and zig-zag air columns for light-fraction removal.

[0073] Secondary sink / float operations can be conducted at various fluid densities depending on the polymers being separated. Densities may range from about 0.80-1.40 g / mL, allowing precise separation based on density. For example, PP0.90-0.92 g / mL) and PE (~ 0.92-0.96 g / mL) can be floated in water, while ABS / HIPS (« 1.03-1.06 g / mL) sink and are recovered separately in water or mildly salted media.

[0074] ASR contains thermoset and thermoplastic rubber contaminants that can accompany polymers during sink / float. These rubber materials must be removed to ensure proper purity, asexcess rubber can create surface imperfections and cause variations in melt viscosity, adversely affecting extrusion and molding. Elastomer over-levels can also impair flame performance and dimensional stability.

[0075] To remove rubber contaminants, friction separators can be employed. The rubber can be first heated to about 100-350 °F or about 150 to 300 °F using hot air or microwave energy to ensure thorough heating. The heated particles are then passed across friction rollers, where the rubber adheres to the rollers and can be pulled from the polymer stream. Process parameters are adjusted to avoid polymer softening that would otherwise increase plastics capture on the rolls.

[0076] To ensure product consistency, polymer composition variations must be minimized. ASR contains variable percentages of different polymers depending on the source, and these percentages can fluctuate daily, weekly, or monthly. Maintaining consistent end-product properties can be crucial to avoid client rejections for non-compliance. Feed-forward control using on-line spectroscopy (e.g., NIR) and periodic DSC / FTIR / TGA checks supports closed-loop adjustment of additive and catalyst dosing.

[0077] One example to maintain composition consistency can be the use of hyperspectral or NIR cameras to estimate relative percentages of various polymers in a blend. This allows accurate calculation of necessary additives and enables belt-fed air separation to remove unwanted polymers or contaminants. When coupled with gravimetric feeders, these measurements maintain melt-index, density, and impact targets within predefined control bands.

[0078] Further separation by polymer type and filler content is required to create consistent feedstreams. Standard sink / float can be insufficient for controlling properties. High-capacitance electrostatic separation can separate polypropylene from polyethylene and ABS from polystyrene (and filled PP or PP with more than 10% filler), including both crystal and high-impact types. Electrostatics can also differentiate polymers filled with glass, talc, or calcium carbonate. Multiple electrostatic stages may be used. Tribo-charging conditions (humidity, conditioning time, and surface treatment) are tuned to maximize differential charging.

[0079] Once separated, the polymers are reblended into controlled formulations to meet desired product specifications. Additives may be introduced to enhance properties and control quality. Representative packages include primary / secondary antioxidants, HALS / UV absorbers, nucleators, lubricants, process aids, odor-adsorbing carbons, and color concentrates.

[0080] To protect extrusion and downstream equipment, all feedstocks can be passed through high-energy magnets prior to extrusion. This step captures any fugitive tramp metals that may have escaped earlier separation processes. Pressure-based interlocks can divert the melt stream upon sudden differential-pressure spikes at the screen changer to prevent downstream contamination.

[0081] As can be seen, specific embodiments provide a highly efficient method for recycling ASR into high-quality, uniform blended plastics by leveraging flotation separation, shredding, direct extrusion, and catalytic modification. The process significantly reduces water-intensive washing while ensuring that the final product can be free of contaminants and exhibits superior mechanical properties due to catalytic repolymerization. The use of accumulators and injectors to control placement and temperature of the polymer charge ensures continuous molding operations, maximizing productivity and enabling a wide range of industrial end products. Quality assurance may be demonstrated through routine rheology (MFR), mechanical (tensile / impact), and odor / VOC testing on molded plaques taken at defined intervals.

[0082] In some embodiments, the compounded melt can be strand-cut or underwater-pelletized after the secondary vented extruder. Pellets are then reheated and molded at satellite facilities. The melt-to-mold and pellet pathways are interchangeable and may be selected based on logistics.Examples

[0083] Exemplary Processing Parameters (Non-Limiting). Primary extruder L / D: about 30-40; barrel temperatures: about 170-230 °C depending on composition; screen-pack differentialpressure alarm: about 25-40 bar; vacuum at second vent: about 10-80 mbar; residence time from last vent to accumulator discharge: less than about 5 minutes.

[0084] Example 1. A mixed PP / PE / HIPS ASR stream (float at 1.00 SG) can be shredded to ~10 mm, aspirated, friction-cleaned, and compounded with 0.5 phr titanate and 0.3 phr antioxidant in a 90 mm vented twin-screw at 210 °C with two vacuum vents (150 mbar and 20 mbar). The melt can be filtered (120-mesh equivalent) and fed to a 50 kg accumulator, then compression-molded into 4 mm plaques. Expected properties include increased notched Izod impact versus an uncoupled physical blend, reduced delamination after 7-day 80 °C aging, and acceptable odor per internal panel scoring.

[0085] Example 2 (Flame-Retarded). A sink fraction enriched in ABS / HIPS can be compounded with magnesium hydroxide, zinc borate, and sepiolite nanoclay plus zirconate coupling. Compression-molded bars at 3.2 mm are expected to achieve at least UL-94 V-2; optimization may achieve V-0 depending on total loading and article design.

[0086] While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions, and subcombinations thereof. It is therefore intended that the following appended claims and claims hereafter are interpreted to include all such modifications, permutations, additions, and subcombinations as are within their true spirit and scope.

Claims

Claims1. A method for recycling Automotive Shredder Residue (ASR) or post-consumer mixed polymer waste, comprising: receiving a feed comprising polymers and contaminants with metals substantially removed; separating the feed by density to obtain a light plastic fraction at a liquid density of about 1.0-1.20 specific gravity; shredding the light plastic fraction to a target size; removing lightweight and heavier contaminants; extruding the separated material through a screen-changed melt filtration zone to remove non-melting contaminants; devolatilizing the melt under vacuum to remove residual automotive fluids and collecting condensed vapors for environmental treatment; during extrusion, introducing one or more coupling agents to reactively compatibilize dissimilar polymers and promote adhesion to fillers; and delivering the modified melt as a compounded material to molding equipment or to a pelletizer.

2. The method of claim 1, wherein the separating by density comprises a water float at about 1.00 specific gravity at 23 °C to float polyethylene and polypropylene and sink higher-density contaminants.

3. The method of claim 1, wherein the separating by density further comprises a float operated at about 1.00-1.10 specific gravity to selectively sink ABS / HIPS and highly filled polyolefins while allowing unfilled PP / PE to float.

4. The method of claim 1, wherein the shredding produces a nominal particle size of about 3 / 8 inch (~ 9.5 mm) with a tolerance of ±30%.

5. The method of claim 1, wherein removing lightweight and heavier contaminants comprises aspirating or air classification followed by friction separation, the friction separationbeing conducted after preheating the feed to about 150 to 350 °F to aid removal of elastomeric residues.

6. The method of claim 1, further comprising, prior to extruding, electrostatically separating the cleaned polymer fraction to produce polypropylene-rich and polyethylene-rich streams.

7. The method of claim 1, wherein coupling agents are selected from organic titanates, zirconates, aluminates, and combinations thereof.

8. The method of claim 1, further comprising, prior to extruding, electrostatically separating the cleaned polymer fraction to produce styrene-rich streams.

9. The method of claim 1, wherein the melt filtration employs a screen-changer selected from slide-gate, bolt-type, laser-screen and continuous-belt screen changers, with a screen equivalent of about 10-200 mesh, and automatic indexing triggered by a differential-pressure threshold.

10. The method of claim 1, wherein devolatilizing the melt comprises at least one vacuum vent including a final deep-vacuum vent, and staged condensers comprising a knock-out pot and a chilled condenser followed by activated-carbon polishing, with non-condensables routed to catalytic or regenerative thermal oxidation.

11. The method of claim 1, wherein the optional additives include a flame-retardant package comprising exfoliated sepiolite nanoclay and zinc borate effective to form a stabilized char with diminished smoke and heat-release rate, whereby molded articles achieve at least UL-94 V-2 at 3.2 mm.

12. The method of claim 1, wherein the optional additives include stabilizers, odor adsorbers, nucleators, lubricants, fillers, flame-retardants, and combinations thereof.

13. The method of claim 1, wherein delivering the modified melt comprises routing the melt to one or more heated accumulators and a diverter manifold for continuous charges tocompression, injection, or structural -foam presses, with an accumulator residence time of less than about 10 minutes and an outlet static mixer to improve temperature and composition uniformity.

14. A method for recycling Automotive Shredder Residue (ASR) or post-consumer waste into uniform blended plastics, comprising: separating materials with a specific gravity less 0.8 to 1.1 using a flotation process to recover low-density polymers; shredding the separated materials to a size of approximately 3 / 8 inch within a 30% size variation; removing water and lightweight contaminants from the shredded material; passing the cleaned material through a friction separator or equivalent alternative such as a trommel or rotary screen separator to refine the polymer fractions; extruding the polyethylene (PE) and polypropylene (PP) materials using an extruder equipped with a screen changer to filter non-melting contaminants; degassing the filter polymers to remove residual automotive fluids, including oils, glycols, and other volatile compounds, and collecting the volatilized fluids for disposal or recovery.

15. The method of claim 14, wherein the volatilized fluids are removed during the extrusion process by using a vacuum chamber and a breaker plate with non-plugging holes, which maximizes surface area for vapor evacuation.

16. The method of claim 14, wherein organic titanates or zirconates are introduced during extrusion to catalytically repolymerize dissimilar polymers, preventing phase separation and improving the elasticity, impact resistance, and processability of the final polymer product. Add another claimed Alumninates as dependant claim.

17. The method of claim 17, wherein the organic titanates or zirconates create a chemical bridge between the polymers and any fillers present in the ASR, improving filler dispersion and adhesion, and allowing for the efficient recycling of mixed waste streams.

18. The method of claim 14, wherein the extruder is equipped with a screen changer, selected from the group consisting of a slide gate, continuous belt, bolt type, or laser screen, to fdter out non-melting contaminants.

19. The method of claim 14, wherein the degassing process volatilizes residual fluids with boiling points below the melting points of polyethylene and polypropylene, and the vapors are collected using standard vapor collection techniques and condensed for environmentally responsible disposal or recovery.

20. The method of claim 16, wherein the catalyst system allows for the effective coupling of residual polymers, including olefinic systems such as PE and PP, styrenic systems such as HIPS and ABS, and engineering-grade polymers such as nylons and polyesters.

21. The method of claim 14, wherein accumulators are used to store molten polymer after degassing, enabling continuous operation of the extruder and uninterrupted supply of polymer to molding presses for compression molding, injection molding, or structural foam molding.

22. The method of claim 4, wherein metallic hydroxides or other flame retardant addatives are introduced during the extrusion process to create a flame-retardant formulation, enabling the polymer to pass the UL-94 flame test.

23. The method of claim 14, wherein the recycled ASR is formulated into a low- temperature olefinic polymer by mixing ethyl ene-propylene rubber into the extruded polymer blend, resulting in a material with improved low-temperature flexibility and a reduced ductile- brittle transition point.

24. A method for producing molded articles from ASR-derived polymers without extensive hot-water washing, comprising: separating an ASR feed to obtain a polymer fraction; shredding and air-handling the polymer fraction;friction-separating to dislodge residues; separating to adjust polyethylene and polypropylene ratios; directly extruding the polymer fraction through a melt filtration zone and devolatilizing the melt at an absolute pressure of about 5-300 mbar while collecting vapors for environmental treatment; reactively compatibilizing immiscible polymer phases by adding one or more coupling agents selected from organic titanates, zirconates, and aluminates, and optionally additives selected from impact stabilizers, FR agents, odor adsorbers, nucleators, lubricants, and fillers; and charging the compatibilized melt to one or more heated accumulators and continuously delivering metered charges to compression, injection, or structural -foam presses to form molded articles.

25. A method for producing molded articles from ASR-derived polymers without extensive hot-water washing, comprising: separating an ASR feed to obtain a polymer fraction; shredding and air-handling the polymer fraction to remove fuzz, paper, fines, dirt, and filled foams; friction-separating to dislodge rubber and laminate residues; directly extruding the polymer fraction through a melt filtration zone and devolatilizing the melt at an absolute pressure of about 5-300 mbar while collecting vapors for environmental treatment; reactively compatibilizing immiscible polymer phases by adding one or more coupling agents selected from organic titanates, zirconates, and aluminates, and optionally additives selected from stabilizers, odor adsorbers, nucleators, lubricants, and fillers; and charging the compatibilized melt to one or more heated accumulators and continuously delivering metered charges to compression, injection, or structural -foam presses to form molded articles.

26. A thermoplastic composition obtainable from ASR or post-consumer mixed polymer waste, the composition comprising:a compatibilized blend of polyethylene and polypropylene in which interfacial regions include reaction products of a coupling agent selected from organic titanates, zirconates, and aluminates; filler particles bearing a monomolecular coupling-agent layer that enhances adhesion to the blend; and wherein the composition is produced by melt filtration and devolatilization that remove non-melting contaminants and residual automotive fluids, and wherein the composition is moldable directly from a heated accumulator to form articles having stabilized morphology relative to a physical blend of the same polymers without the coupling agent.

27. The composition of claim 26, further comprising a flame-retardant package including exfoliated sepiolite nanoclay and zinc borate effective to form a stabilized char with diminished smoke and heat-release rate, wherein molded articles of the composition achieve at least a UL-94 V-2 classification at 3.2 mm thickness.

28. An article formed form the composition of claim 26.

29. A system for processing ASR-derived polymers, comprising: a flotation module configured to separate low-density plastics at about 1.00 specific gravity and, optionally, at about 1.00-1.10 specific gravity; a size-reduction module configured to produce regrind having a nominal size of about 3 / 8 inch; an air handling module comprising at least one of an aspirator, air classifier, or cyclone; a friction separator configured to remove elastomeric residues and adhered contaminants; an electrostatic separator configured to partition polyethylene-rich and polypropylene-rich fractions; a primary extruder including a screen-changer melt filtration assembly; a devolatilization module fluidly coupled to the primary extruder and to an environmental control unit selected from a knock-out pot, chilled condenser, activated-carbon polisher, catalytic oxidizer, and regenerative thermal oxidizer;a secondary vented extruder having additive feeders for introducing coupling agents and other additives; and a downstream delivery subsystem comprising at least one heated accumulator with an outlet to a molding press and an alternative outlet to a pelletizer.

30. The system of claim 29, wherein the flotation module comprises a first water cell at about 1.00 specific gravity (SG) and an optional brine cell at about 1.00-1.20 SG, the module including a density-control loop configured to maintain fluid density within ±0.02 SG at 23 °C.

31. The system of claim 29, wherein the friction separator is preceded by a thermal conditioner configured to heat the feed to 150-350 °F to promote release of elastomeric residues and adhered contaminants.

32. The system of claim 29, wherein the primary extruder includes a continuous-belt screen-changer loaded with screens having an effective mesh of about 10-200, and an automatic indexing control triggered by a differential-pressure threshold of about 25-40 bar.

33. The system of claim 29, wherein the devolatilization module comprises at least one vacuum vent, and the environmental control unit comprises, in series, a knock-out pot, a chilled condenser, and an activated-carbon polisher, with non-condensable gases routed to a catalytic oxidizer or regenerative thermal oxidizer.

34. The system of claim 29, wherein the downstream delivery subsystem comprises at least one heated accumulator having a capacity of 5 to 200 kg, an outlet static mixer, and a diverter manifold configured to selectively supply a molding press and a pelletizer.

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