Optimizing Pelletizing in PET Recycling Processes

A method for producing plastic granules suitable for producing extrusion blow molded hollow bodies of recycled PET with high impact toughness and high gloss, and an extrusion process to achieve it. The method involves adjusting the intrinsic viscosity and molecular structure of recycled PET (rPET) to match virgin PET (vPET) in drop test performance and glossiness. The rPET particles are prepared by crystallization in hot air or infrared heat to control branching and molecular structure. The adjusted rPET properties allow comparable drop heights and gloss in blow molded bottles compared to vPET. This allows recycled bottles with similar performance to virgin ones, which is important for sustainability and recyclability.

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A compact and automated plastic pelletizing machine for recycling plastic waste into pellets for further processing. The machine has a fixed housing with an integrated melting extrusion device, pulling cooling device, mechanical conveyance claw, and pellet collection box. The extrusion device melts and forms the plastic into a strip. The pulling cooling device brings the strip into a pool for cooling. The conveyance claw pulls the cooled strip towards the collection box. This integrated design allows efficient and automated pelletizing of recycled plastic with a compact footprint.

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A method to produce PET pellets with improved crystallization and surface texture for injection molding applications. The method involves granulating PET melt into pellets in an underwater granulator using cold process water below the PET glass transition temperature. The pellets are rapidly separated from the cold water and then subjected to post-treatment stages. The first stage involves nucleus formation by heating the pellets with warm gas at a temperature higher than the pellet surface temperature. This promotes uniform crystallization inside the pellets. The second stage is for further post-treatment after drying.

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A plastic raw material conversion method to manufacture recycled pellets from waste plastic. The method involves melting, extruding, cooling, and cutting the waste plastic to form pellets. The extruded plastic is cooled in a bath, then cut into pellet size. This produces high quality recycled pellets with improved properties compared to direct reuse of waste plastic. The process also involves filtering toxic gases during melting/extrusion, replacing hot cooling water, and separating stuck plastic from hoppers.

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A method for producing polyester resin pellets using an underwater cutter that avoids deformation of the pellets into a curved shape. The key is to set the temperature of the cooling water used in the cutter to 35-100°C. This prevents the pellets from being bent when cut in the water. The temperature range allows the pellets to form spherical shapes instead of curved ones.

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A degradable plastic granulation line that can efficiently produce degradable plastic granules. The line has features like a stirring feeder to prevent material bridging, an air-cooled conveying mechanism to cool the extruded strands, and a drying mechanism after screening to further dry the particles. These modifications are specifically tailored to degradable plastics which require proper mixing, cooling, and drying to prevent degradation during granulation.

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A method for granulating polyester resin that avoids adhesion between particles and allows continuous production without long waiting times. The method involves adding a small amount of a sodium lactate salt, like sodium lactate trihydrate, to the melted polyester before granulation. The lactate salt reduces the viscosity of the polyester and prevents adhesion between granules when they cool. This allows immediate granulation without waiting for the polyester to fully cool and become less viscous.

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A pellet manufacturing process for recycling waste vinyl into pellets without operator injury. The process involves using automated equipment to suck, compress, extrude, cool, dry, and cut the vinyl waste inside the machine. This prevents worker injuries from getting caught in the equipment during manual feeding. The machine also has sensors to stop operation if foreign objects are detected in the waste feed.

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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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Method for producing pellets from thermoplastic resin compositions that reduces hollow pellets while keeping moisture content low. The method involves extruding the strand, cooling it in water, and then air cooling it before pelletizing. The water cooling step involves drawing the strand into a tank filled with water to isotropically cool it. This prevents hollow pellets by preventing uneven solidification. The air cooling step further cools the water-cooled strand before pelletizing. The combination of water and air cooling steps provides isotropic cooling and reduces hollow pellets compared to just air cooling.

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Ultra-high intrinsic viscosity (IV) polyester resin suitable for extrusion blow molding applications that can be produced using a novel method. The resin has a final IV of at least 0.9 dL/g, achieved by melting and extruding the resin at a temperature below its crystallization point, followed by solidifying and pelletizing. This avoids the long solid-state polymerization step needed for conventional high IV resins. The lower processing temperature prevents crystallization and results in a clear, amorphous resin. The method provides a faster, energy-efficient, and more cost-effective way to make high IV polyesters for applications like handleware containers.

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Reducing breakage of thermoplastic composite pellets by optimizing strand cooling and guiding during pelletization. The method involves curving the extruded strand before cutting to suppress runout and breakage. The strand is guided through water and air with specific angles and lengths to prevent excessive flexibility. The strand is extruded into air, then drawn into water where it is curved by a guide roller. The angle between strand sections is kept above 90° but below 180°. The strand length in water is calculated based on velocity. After water cooling, the strand is curved again by an air guide roller. This prevents excessive runout and breakage during pelletizing.

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A new material processing granulator that improves the efficiency of granulating degradable plastics like bioplastics. The granulator has features like a vertical screw extruder, a granulation chamber with air flow, and a rotating shear to quickly cool and shape the granules. The vertical screw extrudes the plastic into thin strips that are sheared into small granules by the rotating shear. Air flow inside the chamber cools the granules before discharge. This prevents sticking and clumping. The vertical air flow also prevents agglomeration during discharge. The granulator also has features like a prilling pan, impeller, and exhaust port for efficient granulation and discharge.

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Method for producing PTT (Polytrimethylene Terephthalate) pellets containing inorganic particles like silica, zeolite, and Ag-zeolite. The method involves stirring PTT resin chips with inorganic particles, heating and extruding the mixture in stages, spinning the extruded material, coagulating the spun pellets, and cutting them into final pellet shape. The stages and speeds of the screws in the extruder and spinning machine are optimized to evenly disperse and attach the inorganic particles to the PTT resin. This produces PTT pellets with uniformly dispersed inorganic particles for use in bedding materials as a replacement for down feathers.

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Water-cooled granulation equipment for recycling waste plastics that uses flowing water and swing motion to cool and cut the plastics into pellets. The equipment has a water-cooled forming device, storage tank, and air-drying discharger. The forming device molds the softened plastics, cools them, cuts them, and feeds them to the tank. The tank further cools the pellets. Swinging blocks and a scooping mechanism move in the tank to agitate and aerate the pellets. This enhances cooling and drying. The plastics are then air-dried and discharged. The swing motion and water cooling provide better pelletization compared to just air drying.

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Automatic polyester chip pelletizing equipment that improves production efficiency by providing a fully automated process to make polyester chips from resin. The equipment extrudes the resin, cuts it into pellets, partitions it, demolds the pellets, and cools them all in an automated sequence. Features like sliding parting plates, a demolding assembly, and a cooling system allow continuous, automated processing without manual intervention.

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Recycling method for producing high quality recycled PET granules from contaminated PET flakes. The method involves polycondensation of the flakes at high temperature and low pressure to form intermediate PET granules. This is followed by washing, drying, and sifting to remove contaminants. The resulting recycled PET granules have low contamination levels, stable properties, and can be used in applications like food packaging and yarn production. The key process steps are high temperature polycondensation, washing, and sifting.

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A manufacturing method for resin pellets that reduces defects like double-linked pellets, multi-linked pellets, and deformed pellets. The method involves extracting strands of molten thermoplastic resin at specific diameters and speeds, cooling them with refrigerant at specific spacing, and cutting them into pellets. The strand spacing formula closely matches normal distribution for minimal bonding. This prevents bonding and deformation during cooling, improving pellet quality.

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Manufacturing method and apparatus for liquid crystalline polyester resin pellets that provides stable discharge of the melted resin from the die head, improves productivity, and reduces foreign substances. The method involves supplying the melted resin through a valve to a die head, discharging it through a port with small die holes, and using a perforated plate with larger holes upstream. This prevents blocking, fluttering, and irregular pellets. The perforated plate diameter is 0.1-1.2 times the die hole diameter.

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A method to produce highly polymerized polyester resin with uniform quality pellets that do not have rounded corners at the ends. The method involves melt-extruding the polyester resin using a rectangular nozzle shape instead of a circular shape. This produces pellets with a cylindrical shape with specific ratios of straight portion (c) to radius (b) and end radius (d) to radius (b) in order to avoid rounding corners during cooling and cutting. The ratios are 1.5 ≤ c / b ≤ 3.9 and 0.6 ≤ d / b ≤ 1.4. This prevents issues like tailing, uneven quality, and decreased strength in the final product.

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