Extrusion in PET Bottle Recycling

A method for recycling waste PET bottle flakes into sheet materials with improved quality and higher waste PET content compared to traditional recycling methods. The method involves a two-step polycondensation process to reduce degradation and color impurities. First, the PET flakes are alcoholysised with ethylene glycol to partially depolymerize and reduce viscosity. Then, the alcoholysis product is homopolymerized and solid-state polycondensation is performed. This produces high-quality sheet materials with lower viscosity and shorter polycondensation times compared to direct recycling. The alcoholysis step allows better molecular weight control and reduces degradation during subsequent polymerization.

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Device to efficiently recycle waste plastic into new synthetic threads using a pretreatment, melting, and spinning process. The device has a pretreatment section for preparing waste like shredded fabric, a melting section to turn the pretreated waste into a plastic melt, and a spinning section to extrude threads from the melt. This allows recycling of textile plastics like PET bottles into new threads without the complex and costly steps of granulation and filtration.

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Recycling PET chips from waste bottles to increase their intrinsic viscosity and purity for reuse in high-quality applications like long fiber textiles, new bottles, and sheets. The process involves heating and rotating the chips in a blender to crystallize them, extruding the crystallized chips, cutting them underwater, separating and sorting the chips, further crystallizing them, drying, and packaging. The extrusion step is done using a vacuum screw to maintain vacuum pressure. This sequence enhances intrinsic viscosity and purity compared to direct melting and reuse.

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Producing thin-walled containers for food storage that can be easily demolded and won't shatter when dropped, using recycled PET (rPET) produced via a specific process. The process involves blending virgin PET with a low viscosity (0.5-0.7 dl/g) and recycled PET (rPET) with higher viscosity (0.01-0.4 dl/g) in a reactive extrusion step. The blended material is then injection molded into thin-walled containers. The reactive extrusion lowers the viscosity of the recycled PET to match the virgin PET for injection molding. The containers have a wall thickness of 0.1-0.5 mm and a smaller bottom area than the opening.

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Recycling process for plastic packaging without separating the printed layer. The recycling involves melting and extruding the laminated packaging material using an extruder. The laminate contains a polyester base and a printed layer with low chlorine content. The chlorine level in the total laminate is 0.4% or less. The extrusion temperature is 260-290°C. This allows producing high-quality recycled plastic with good moldability without removing the printed layer. The low chlorine level prevents halogen gas and acid generation during extrusion. The laminate is also dehydrated to <0.2% moisture before extrusion.

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Method to produce polyester starting material for extrusion blow molding of hollow articles like PET bottles from recycled post-consumer PET. The method involves melting and reactively extruding the recycled PET with chain extenders to increase viscosity for blow molding. The chain extenders can be dianhydrides like pyromellitic dianhydride. The extruded melt is filtered and granulated. This provides a recycled PET with higher viscosity suitable for blow molding without needing additives or long condensation times.

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Producing recycled PET (rPET) for extrusion blow molded bottles that have comparable impact strength and gloss to virgin PET (vPET) bottles. The rPET is produced by crystallizing and granulating recycled PET with an intrinsic viscosity (IV) of 0.9-1.7 dl/g. The rPET bottles have similar drop height and gloss to vPET bottles with the same weight. The rPET's higher elasticity due to branching limits recycling to injection molding applications.

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Using waste plastics containing PET, like colored plastics, PET-containing mixtures, and PET-containing byproducts from recycling facilities, as feedstock for chemical recycling processes like solvolysis. This allows recycling of plastics that cannot be efficiently recycled mechanically, like mixed waste plastics, by extracting the PET. The PET-containing waste is fed directly to the chemical recycling facility without preprocessing, and depolymerization converts the PET back to monomers. This enables closing the loop on hard-to-recycle waste plastics by extracting valuable PET for recycling.

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Recycling post-consumer PET bottles into carpet yarn using a multi-rotating screw (MRS) extruder. The PET bottles are sorted, ground, washed, and dried to remove impurities. The ground flakes are melted and purified in the MRS extruder, which has multiple satellite screws to expand the melt area and remove volatiles. The purified melt is extruded directly into the carpet spinning machine to make recycled carpet yarn. This allows making 100% recycled carpet yarn from bottles without using virgin PET.

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A method to produce PET material with higher viscosity suitable for extrusion blow molding of plastic bottles, using recycled PET as the starting material. The method involves increasing the intrinsic viscosity of recycled PET by solid state polycondensation (SSP) after extrusion. The extruded PET is first mixed with a chain extender, then extruded again. This extruded PET is then subjected to SSP at temperatures below the melting point to further increase viscosity. This allows producing PET with higher viscosity suitable for blow molding from recycled material without requiring high temperatures or long times.

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A method for recycling and granulating waste polyester like PET bottles and films to create a reusable product with improved quality and processability compared to directly granulating the waste. The method involves chain extending the waste polyester to increase the molecular weight, reducing the viscosity variability. This involves adding a chain extender like diethylene glycol, ethylene glycol, or diethanolamine to the waste polyester during extrusion. After chain extension, the polymer is filtered to remove impurities and then extruded again at higher temperatures to form thicker filaments for further processing like wire drawing. This results in a recycled polyester with better properties and consistency for downstream applications compared to directly granulating the waste.

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A process to recycle multilayer PET containers with high PET content that can't be recycled due to incompatibility between the layers. The process involves separating the film and labels from the containers to obtain clean multilayer PET. Then, the multilayer PET is fused to homogenize the material. After fusion, the homogenized multilayer PET can be mechanically recycled. The fusion step blends the layers to create a homogeneous material that can be processed like regular PET.

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Method for recycling polyester resin from used PET bottles and other products to make new bottles without degradation. The recycling involves a two-step solid-state polymerization process that regenerates the degraded polyester resin. In step 1, the crushed flakes are heated under reduced pressure above the glass transition but below melting temperature to partially solid-state polymerize. In step 2, the flakes are plasticized, melt-kneaded, and granulated into pellets. Then they are heated under reduced pressure again at higher temperature to fully solid-state polymerize. This regenerates the polyester quality for reuse as a recycled material in new bottles.

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Manufacturing 100% recycled carpet yarn from post-consumer PET bottles using a specialized extrusion process. The method involves preparing the PET flakes from bottles, melting and purifying them in an extruder, and spinning them into carpet filaments. The extruder uses a multi-stage screw design and pressure control to remove impurities and water from the recycled PET. The flakes are first crystallized to remove moisture before extrusion. This allows making high-quality recycled PET filaments for carpet without using virgin PET.

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A method to make recycled PET chips with high viscosity and purity from low-grade recycled PET flakes. The method involves steps like pulverizing low-IV PET flakes, sorting transparent flakes, pre-drying, dehumidifying, extruding, and crystallizing the surface of the chips. By blending thickeners and controlling moisture levels, it converts low-quality PET into higher-viscosity, high-purity chips suitable for making products with added value.

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Twin-screw extruder for efficiently melting and drying polyester chips without pre-drying and steam requirements. The extruder has two parallel screws in a horizontal housing with rhombus-shaped extrusion protrusions on the screw blades. The screw sections have gradually decreasing blade pitches from feed to discharge to increase shearing and extrusion force. This improves melting and drying of the chips. The feeding mechanism conveys chips into a silo that connects to the extruder inlet. The extruder has a drive motor, reducer, and cooling system. The conveyor and silo allow feeding chips without a rotary drum.

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Apparatus for making recycled plastic pellets with improved quality. The process involves sorting, pulverizing, stirring, extruding, cooling, and cutting waste plastic to form pellets. The stirring step with a moving pipe agitator helps mix and homogenize the pulverized waste plastic before extrusion. This improves pellet quality compared to directly extruding the pulverized plastic. The stirring also allows loading the extruder with agitated plastic instead of static powder, further aiding mixing.

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A method for producing high-quality, food-grade recycled PET flakes from used bottles that avoids the energy-intensive, costly depolymerization step. The method involves crushing, cleaning, and drying the PET bottles, melting and extruding them, then vacuum devolatilizing and depolymerizing the melt in a single-screw extruder. The depolymerized low-viscosity PET is mixed with virgin PET resin and polycondensed to form the recycled flakes. This eliminates the need for separate depolymerization and purification steps.

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A production device and process for recycling, granulating and reusing high-quality bottle flakes to improve the quality and stability of recycled materials. The process involves using a specialized device with multiple stages to clean, dry, and screen the bottle flakes before granulation. This removes impurities and provides consistent flake size and weight for pelletizing. The stages include quantitative metal removal, eddy current separator, material separator, fluidized bed, circular vibrating screen, and drying tower. The cleaned flakes are fed to an extruder, melt filter, casting head, pelletizer, spin dryer, and linear screen for granulation.

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A process for making carpet yarn from 100% recycled polyethylene terephthalate (PET) bottles using a specialized extrusion system. The process involves: grinding and washing recycled PET flakes, melting and purifying the flakes using a multi-screw extruder with low pressure regulation, and pelletizing the purified PET into nurdles. The low pressure extrusion removes impurities without melting and cooling multiple times. This allows using lower quality recycled PET like curbside bottles to produce high-quality yarn for carpets.

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