| HS Code | |
| Chemical Name | Polyethylene Terephthalate |
| Abbreviation | PET |
| Polymer Type | Thermoplastic polyester |
| Molecular Formula | (C10H8O4)n |
| Repeat Unit | Ethylene terephthalate |
| Density | 1.33–1.40 g/cm³ |
| Melting Point | 250–260 °C |
| Glass Transition Temperature | 67–81 °C |
| Crystallinity | Amorphous to semi-crystalline, up to about 50% |
| Tensile Strength | 55–75 MPa |
| Tensile Modulus | 2.8–3.1 GPa |
| Elongation At Break | 50–300% |
| Flexural Modulus | 2.8–3.1 GPa |
| Hardness | Rockwell M94–M101 |
| Water Absorption | 0.1–0.2% after 24 hours |
| Thermal Conductivity | 0.15–0.24 W/(m·K) |
| Coefficient Of Thermal Expansion | 6–8 × 10^-5 /K |
| Specific Heat Capacity | 1.0–1.3 J/(g·K) |
| Dielectric Constant | 3.0–3.4 at 1 MHz |
| Volume Resistivity | >10^16 Ω·cm |
| Refractive Index | 1.57–1.64 |
| Oxygen Barrier | Good; low oxygen permeability |
| Carbon Dioxide Barrier | Good; low carbon dioxide permeability |
| Moisture Barrier | Moderate |
| Chemical Resistance | Good resistance to acids, alcohols, and oils; poor resistance to strong alkalis |
| Uv Resistance | Moderate to poor without stabilizers |
| Flammability | Self-extinguishing; UL94 HB |
| Recyclability | Recyclable; resin identification code 1 |
| Transparency | Transparent when amorphous; opaque white when crystalline |
| Odor | Odorless |
| Taste | Tasteless |
As an accredited Polyethylene Terephthalate (PET) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Polyethylene Terephthalate (PET) is supplied in 25 kg polyethylene-lined bags, palletized and shrink-wrapped for industrial transport. |
| Container Loading (20′ FCL) | Chemical Polyethylene Terephthalate (PET) loaded into a 20′ FCL container, palletized or bagged, and secured for safe ocean transport. |
| Shipping | Polyethylene terephthalate (PET) is nonhazardous and typically shipped as solid resin pellets in 25-kg bags, supersacks, bulk trucks, railcars, or containers. Keep dry and protected from heat, sunlight, and contamination. Use sealed liners; standard freight applies, with no dangerous-goods placarding required for ordinary PET resin. |
| Storage | Store PET at ambient temperature in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, and ignition sources. Keep containers tightly closed to prevent moisture absorption and contamination. Avoid strong oxidizers. Use secondary containment, and ground equipment to control static during transfer. Maintain clean, labeled packaging; protect pellets from UV and excessive stacking. |
| Shelf Life | PET resin has a 2–5-year shelf life when stored dry, sealed, and protected from heat, moisture, and UV light. |
On high-cavitation rotary injection stretch blow moulding platforms producing still water preforms, the incoming bottle-grade PET chip is specified at an intrinsic viscosity of 0.78–0.82 dL/g measured in 60/40 phenol/1,1,2,2-tetrachloroethane according to ASTM D4603. Desiccant wheel drying at a dew point of ≤ -40°C and a residence time of 4–5 h at 160–170°C reduces residual moisture to ≤ 50 ppm because PET undergoes hydrolytic chain scission in the melt when moisture exceeds this threshold. The reciprocating screw is typically specified with an L/D of 20:1 to 24:1, a compression ratio of 2.5:1, and barrel zones profiled from 270°C at the feed throat to 280–285°C at the metering section and hot runner tip. Melt residence time is held below 2 minutes to limit intrinsic viscosity loss to ≤ 0.02 dL/g and to suppress thermal generation of acetaldehyde. Preform injection pressures of 700–1,200 bar and holding pressures of 350–600 bar are common, while clamp force per cavity is normally 250–600 kN. The preform cooling water loop is maintained at 8–12°C, and the cycle time for an 18–25 g preform on a high-cavitation platform is typically 12–20 s depending on hot runner balance and cavitation. Food-contact compliance for these preforms is anchored to FDA 21 CFR 177.1630 and EU Regulation No 10/2011, Annex I. Under the EU regime, overall migration is tested by EN 1186-1 and must not exceed 10 mg/dm², while specific migration of ethylene glycol and terephthalic acid is assessed by validated methods when the finished article is tested with food simulants assigned under Annex III.
| PET downstream segment | Intrinsic viscosity window (dL/g) | Residual moisture before melting | Melt processing temperature range | Critical test method |
|---|---|---|---|---|
| Still water preform | 0.78–0.82 | ≤ 50 ppm | 270–285°C | ASTM D4603; ASTM F2013 |
| Carbonated soft drink preform | 0.82–0.86 | ≤ 30 ppm | 275–285°C | ASTM D4603; ASTM F2013 |
| POY/FDY continuous filament | 0.62–0.66 | ≤ 30 ppm | 280–290°C | ASTM D4603; ASTM D3822 |
| Biaxially oriented PET film | 0.63–0.68 | ≤ 50 ppm | 275–285°C | ASTM D4603; ASTM D1003 |
| Thermoformed food tray sheet | 0.60–0.65 | ≤ 50 ppm | 280–300°C | ASTM D4603; EN 1186-1 |
| Glass-reinforced engineering compound | 0.65–0.75 | ≤ 50 ppm | 270–285°C | ASTM D4603; ISO 527-2 |
| High-tenacity strapping | 0.80–0.85 | ≤ 50 ppm | 270–285°C | ASTM D4603; ISO 527-3 |
Reheat-blow moulding of carbonated soft drink preforms is limited less by mechanical blow pressure than by acetaldehyde concentration in the preform wall, because acetaldehyde migrates from the bottle wall into the carbonated beverage and is detected as a fruity off-note. A 0.33 L carbonated soft drink preform is normally controlled to ≤ 3 ppm acetaldehyde, while still water preforms can tolerate ≤ 8 ppm. The acetaldehyde concentration is measured on moulded preforms by headspace gas chromatography according to ASTM F2013. Solid-state polycondensation of bottle-grade chip reduces residual acetaldehyde to ≤ 1 ppm before drying, but subsequent melt processing regenerates acetaldehyde through ester pyrolysis and thermal rearrangement of vinyl ester end groups. Barrel temperatures above 285°C, melt residence times greater than 2 minutes, and excessive shear heating from high screw rotation all increase regeneration. Typical barrel settings for carbonated soft drink preforms are profiled from 270–275°C at the feed throat to 280–285°C at the metering section, while back pressure is maintained at 40–80 bar to keep melt homogeneity without excessive work input. The extruder screw is specified with a compression ratio of 2.2:1 to 2.5:1 for bottle-grade formulations to limit temperature overshoot, and the hot runner and valve-gate tips are separately controlled at 275–280°C. Acetaldehyde concentration also depends on preform wall thickness and injection cooling rate; thicker preforms retain the melt above the glass transition temperature for longer, allowing additional time for degradation. In practice, preform cooling water at 8–12°C and cooling time of 8–14 s reduce the residual degradation window.
Where continuous filament yarn producers run PET with an intrinsic viscosity of 0.62–0.66 dL/g, the dominant stability variable is spin pack pressure rather than absolute molecular weight. Chip is dried at 160–170°C for 4–6 h to reach residual moisture of ≤ 30 ppm, then melted in extruders with L/D ratios of 24:1 to 30:1 at 280–290°C. Melt filtration through 15–25 µm sintered metal or pleated mesh filter media removes gels and agglomerated titanium dioxide before the polymer enters a spinneret with hole diameters of 0.20–0.35 mm for partially oriented yarn and 0.25–0.45 mm for staple or thick denier filament. Spin pack pressure at a spinneret hole count of 3,000–5,000 holes per metre typically operates between 80–180 bar depending on throughput; a progressive pressure rise above 200 bar indicates filter blinding and requires a pack change. Quench air at 18–22°C and 0.30–0.50 m/s crossflow impinges directly beneath the spinneret, and spin finish loading of 0.3–0.5 wt% is applied to running yarn through ceramic kiss rolls or metered finish jets to control electrostatic charge and interfilament cohesion. For POY, draw ratios of 1.5–2.0:1 between godets at 80–100°C produce break elongation suitable for draw texturizing; FDY lines apply total draw ratios of 3.0–4.5:1 with hot roll temperatures from 80–130°C and a separate relaxation stage. Final filament tenacity for apparel-grade FDY is typically 4.0–4.5 cN/dtex at an elongation at break of 20–30% when tested according to ASTM D3822. Published data for spin pack pressure profiles at spinneret hole densities above 5,000 holes/m² are limited; production validation on such configurations is therefore conducted with pressure sensors mounted in the pack top rather than extrapolated from lower-density data.
Cast film lines running biaxially oriented PET sheet begin with a chip whose intrinsic viscosity is 0.63–0.68 dL/g and whose moisture content after drying is ≤ 50 ppm. Melt is delivered to the flat die at 275–285°C, with the die gap set at 1.5–3.0 mm for film thicknesses between 10–50 µm after orientation. Electrostatic pinning, with a wire voltage of 6–10 kV, holds the melt to a chilled cast roll at 25–45°C to stabilize quench and reduce air entrapment. The primary machine-direction draw ratio is 3.0–3.5:1 at preheat temperatures of 95–105°C, followed by transverse stretching in a tenter oven at 3.2–3.8:1 with clip chain speed matched to line tension. Die lip build-up from cyclic trimer and low-molecular oligomer is a continuous operational constraint; oligomer deposits cause local flow disturbances and film thickness defects unless the die lips are cleaned periodically or the die design incorporates a purge zone. Optical quality is verified by haze measurements below 2.0% under ASTM D1003 and gloss above 100 GU at 60° under ASTM D523. Food-contact film must meet FDA 21 CFR 177.1630 and EU Regulation No 10/2011, with overall migration below 10 mg/dm² by EN 1186-1. Published data for ultra-thin capacitor-grade PET film below 3 µm thickness are limited, and process validation on such configurations is usually performed on pilot cast-film lines rather than transferred directly from packaging-grade parameters.
Injection moulding of glass-reinforced PET electrical connectors begins with an unreinforced IV of 0.65–0.75 dL/g and a chopped E-glass strand of 10–13 µm diameter coated with an aminosilane coupling agent. The compound is dried to ≤ 50 ppm residual moisture before melt mixing and injection at 270–285°C. Reinforcement loading between 15–30 wt% raises tensile strength to 120–140 MPa according to ISO 527-2 and flexural modulus to 8–10 GPa according to ISO 178. Notched Izod impact measured by ISO 180/A is typically 6–8 kJ/m² depending on fibre length retention in the screw and mold fill pattern. The critical process requirement is that the mold temperature be held at 120–140°C so that the part crystallizes in the tool; below 100°C, the surface freezes before adequate crystallization and the part exhibits post-mold dimensional movement and reduced chemical resistance. Flame-retarded grades formulated to meet UL 94 V-0 at 0.4–0.8 mm are tested under IEC 60695-11-10, and RoHS compliance is verified by IEC 62321-3-1 for lead, mercury, chromium(VI), and cadmium. Dielectric strength is tested by IEC 60243-1, and comparative tracking index is measured by IEC 60112 for creepage distance calculations. Polyester compounds used in electrical parts must avoid prolonged contact with amine-based epoxy hardeners and alkaline cleaning media above pH 9 because hydrolysis accelerates at high pH and sustained temperatures above 85°C.
Thermoformed food trays incorporating post-consumer rPET above 30% require a supply chain operating under a validated recycling process, because direct food-contact use of recycled plastic in the EU is controlled by Regulation (EC) No 282/2008 and in the United States by an FDA letter of no objection or an applicable food-contact regulation. The incoming washed flake is usually solid-state polycondensed to an intrinsic viscosity of 0.70–0.75 dL/g to compensate for hydrolytic and thermal chain scission during subsequent sheet extrusion. On a coextruded sheet line, a virgin PET skin with an IV of 0.60–0.65 dL/g may be combined with an rPET core in an ABA structure, and the extruders are specified with L/D ratios of 33:1 to 36:1 and vacuum venting of -0.8 bar to strip residual volatiles. Melt temperatures are held at 280–300°C for sheet with thickness 0.25–1.2 mm, and the roll stack temperature is controlled at 30–60°C to minimize sag and control sheet thickness. The formed article is plug-assist processed in matched metal or aluminium tools at 100–110°C with forming air pressures of 4–7 bar for thin-wall trays, and cycle times are typically 4–8 s. Compliance for the final tray is verified by overall migration using EN 1186-1 and specific migration testing for constituents listed in EU Regulation No 10/2011, Annex I. Published data for exact surrogate removal on any given flake source are limited; validation is therefore carried out on the specific recycling process rather than generalized from virgin PET migration data.
| Region or application | Regulation or directive | Critical test or specification | Numerical limit |
|---|---|---|---|
| EU food contact virgin PET | EU Regulation No 10/2011, Annex I | EN 1186-1 overall migration | ≤ 10 mg/dm² |
| US food contact PET | FDA 21 CFR 177.1630 | 21 CFR extraction testing | food-type dependent extraction limits |
| EU recycled PET food contact | Regulation (EC) No 282/2008 | EFSA recycling process opinion | surrogate contamination removed below modelled threshold |
| EU RoHS for electrical compounds | Directive 2011/65/EU, Annex II | IEC 62321-3-1 | Pb ≤ 1000 ppm; Hg ≤ 1000 ppm; Cd ≤ 100 ppm |
| Flame retardancy | UL 94 | IEC 60695-11-10 | V-0 at 0.4–0.8 mm |
A high-tenacity PET strapping line operates with a chip intrinsic viscosity of 0.80–0.85 dL/g and requires drying to ≤ 50 ppm because the molten web is immediately water-quenched, and any residual moisture before extrusion lowers molecular weight before orientation can develop tensile strength. Extrusion is performed through a slot die at 270–285°C, followed by cold water quenching at 15–25°C and reheating in a hot-air or hot-water stretch zone. The orientation ratio is commonly 5.0–6.0:1 for high-tenacity strap, producing a tensile strength of 400–500 MPa and an elongation at break of 12–15% measured by ISO 527-3 or ASTM D638. The operational boundary is hydrolytic attack at high humidity and elevated temperature; PET strapping exposed to 85% relative humidity at 23°C undergoes stress relaxation and tensile-strength loss if stored in contact with water or alkaline surface contamination. Contact with concentrated acidic media such as 10% hydrochloric acid is outside the normal specification, and field data published for such configurations is limited.
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Polyethylene terephthalate (PET) is a semicrystalline thermoplastic polyester formed from ethylene glycol and purified terephthalic acid or dimethyl terephthalate. Its repeat unit is –OCH₂–CH₂–OCO–C₆H₄–CO– and its CAS registration number is 25038-59-9. ISO 1043-1 designates the material as PET. Commercial product lines are not a uniform material; they are segmented by intrinsic viscosity, comonomer content, crystallinity, carboxyl end-group concentration, residual acetaldehyde, color coordinates, and fines level. Product models are therefore specified by these analytical properties rather than by a single resin name.
Continuous melt-phase polymerization is followed by solid-state polymerization for high-viscosity grades. Melt-phase lines operate under high vacuum to remove ethylene glycol and water; antimony, germanium, or titanium catalysts are commonly used. Solid-state polymerization raises intrinsic viscosity by continuing esterification and transesterification in the solid state at 200–235 °C under vacuum or purified nitrogen for 12–24 h, depending on target molecular weight. This two-stage route is standard for bottle resin because it increases molecular weight while simultaneously reducing residual acetaldehyde and homogenizing crystallinity.
Intrinsic viscosity is measured according to ASTM D4603-18 or ISO 1628-5:2015 using a 60/40 phenol/1,1,2,2-tetrachloroethane solvent mixture at 30 °C. Typical unfilled product specifications are 0.58–0.68 dL/g for biaxially oriented film, 0.60–0.65 dL/g for staple fiber, 0.74–0.80 dL/g for water-bottle preforms, 0.78–0.84 dL/g for carbonated soft-drink preforms, and 0.90–1.05 dL/g for injection-molded engineering articles compounded with glass fiber or mineral fillers.
However, intrinsic viscosity alone does not define processability. Isophthalic acid and diethylene glycol comonomer concentrations, typically in the 1–3 mol% and 0.8–2.0 mol% ranges respectively for bottle grades, suppress melt crystallization and alter preform reheat performance. Carboxyl end-group concentration controls hydrolysis kinetics and is specified at ≤ 35 mmol/kg for many bottle resins. Solid-state polymerization does not simply increase molecular weight; it also reduces volatile organic by-products and narrows the carboxyl end-group distribution.
Biaxially oriented PET film is produced by flat-die extrusion onto a chilled roll at 20–30 °C, followed by sequential or simultaneous stretching. Oriented film reaches tensile modulus values of 4000–6000 MPa in the stretch direction as measured by ISO 527-3:2018. Clear film haze is commonly 1–3%. Film-grade PET is specified for capacitor films, flexible packaging, labels, and solar backsheets where dimensional stability and optical clarity are required.
Fiber-grade PET is melt-spun at 280–295 °C through spinnerets, then drawn to partially oriented yarn or fully drawn yarn. Drawn fiber tenacity is typically 4.0–8.0 cN/dtex with elongation at break of 15–35% under ISO 2062:2009. In staple fiber and continuous filament production, molecular weight uniformity is critical because periodic draw breaks on high-speed lines are associated with intrinsic viscosity fluctuation exceeding ± 0.02 dL/g.
Residual moisture in dried PET is the principal independent variable controlling melt-phase hydrolysis. Pellets equilibrated at 50% relative humidity may contain 0.2–0.4 wt% water; conversion without drying reduces molecular weight through ester bond scission and produces surface splay and preform haze. Desiccant wheel dryers with a dew point of ≤ −40 °C are specified. Drying at 160–180 °C for 4–6 h lowers moisture to ≤ 0.005 wt% (50 ppm) for general molding and ≤ 0.003 wt% (30 ppm) for bottle-grade preform molding. Hopper residence above 190 °C causes surface thermal oxidation and yellowing.
Melt processing is constrained by a narrow thermal window. Barrel temperatures of 270–290 °C are common for preform injection; prolonged residence above 5 min at 285 °C accelerates chain scission and acetaldehyde formation. Compounding lines using twin-screw extruders with 28:1–40:1 L/D ratios apply vacuum venting to strip residual volatiles. Mold surface temperatures for amorphous preforms are held at 10–15 °C to prevent premature crystallization, whereas heat-set bottle molds operate at 120–140 °C to promote stress-relaxed crystallinity.
Acetaldehyde is a thermal degradation product generated by β-scission of vinyl ester end-groups and by melt-phase oxidation. Bottle-grade resin is routinely specified at ≤ 3 µg/g for carbonated soft drinks and ≤ 2 µg/g for water packaging, measured by headspace gas chromatography according to ASTM F2013-10. Preform limits are higher because molding adds acetaldehyde; many converters specify ≤ 8 µg/g in the finished preform. The compound partitions into package headspace and alters beverage flavor at concentrations that are not toxicologically significant.
The processing window is therefore governed by the balance between temperature, residence time, and intrinsic viscosity. Melt temperature should remain at 270–280 °C for bottles where flavor neutrality is critical. Hot-runner manifold temperatures are offset no more than 5–10 °C above the barrel set-point. Screw recovery time, cushion, and decompression are adjusted to keep melt residence time near 2–3 min. High-velocity valve-gated hot runners reduce shear heating and are preferred on 96–192 cavity preform lines. Acetaldehyde generation is also reduced by high-vacuum solid-state polymerization, which strips acetaldehyde to <1 µg/g before drying and melt conversion.
Injection stretch blow molding converts the preform into a biaxially oriented hollow container by reheating to 95–110 °C and stretching with a mechanical stretch rod while high-pressure air forms the vessel. Axial stretch ratios of 2.5–3.0 and hoop stretch ratios of 2.0–2.5 are typical for 500 mL carbonated soft drink bottles. Sidewall crystallinity after orientation is 20–30% as measured by differential scanning calorimetry per ISO 11357-3:2018. Oriented crystallinity plus molecular alignment raises tensile modulus in the hoop direction above the isotropic value, which permits lightweighting while retaining top-load and burst strength.
Heat-set blow molding for hot-fill and pasteurization uses mold temperatures of 120–140 °C to raise effective crystallinity and reduce shrinkage. Standard cold-fill bottles are not specified for continuous service above 60 °C; heat-set PET can tolerate fill temperatures up to 85 °C without unacceptable panel deformation. Blow molding equipment with servo-controlled stretch rods and pressure profiling is required for repeatable material distribution in lightweight preforms.
Comparative property measurements separate PET from polycarbonate, polybutylene terephthalate, and polyolefins in transparent packaging and engineering applications. Unfilled PET provides tensile yield strength of 55–75 MPa and tensile modulus of 2800–3100 MPa under ISO 527-2:2012. These values exceed unfilled polypropylene and are comparable to polycarbonate; however, PET is notched-impact limited at 2–4 kJ/m² and heat-deflection limited at 70–80 °C at 1.82 MPa per ISO 75-2/A:2020. Polycarbonate retains notched Izod values of 60–80 kJ/m² and is therefore selected where impact performance dominates.
| Property and test method | PET | PBT | PETG | PC |
|---|---|---|---|---|
| Density, g/cm³ (ISO 1183-1:2019) | 1.38–1.40 | 1.30–1.32 | 1.27 | 1.20 |
| Tensile strength at yield, MPa (ISO 527-2:2012) | 55–75 | 50–60 | 48–53 | 60–70 |
| Tensile modulus, MPa (ISO 527-2:2012) | 2800–3100 | 2500–2800 | 1900–2100 | 2300–2400 |
| Notched Izod impact at 23 °C, kJ/m² (ISO 180/A:2019) | 2–4 | 4–7 | 9–12 | 60–80 |
| Heat deflection temperature at 1.82 MPa, °C (ISO 75-2/A:2020) | 70–80 | 50–60 | 63–70 | 125–135 |
| Water absorption 24 h, % (ISO 62:2008) | 0.2–0.3 | 0.1 | 0.2 | 0.2 |
In barrier performance, biaxially oriented PET film transmits far less oxygen than polyolefins at equivalent thickness. Oxygen transmission rates measured by ASTM D3985-17 at 23 °C and 50% relative humidity are commonly reported in the range 50–150 cm³/(m²·day·bar) for 25 µm oriented PET film; polyethylene and polypropylene films of equal thickness transmit oxygen at magnitudes of 1000–2000 cm³/(m²·day·bar). Polycarbonate is also a poor oxygen barrier under these conditions. This differential makes PET suitable for carbonated soft drink and oxygen-sensitive food packaging. Water-vapor barrier remains moderate, and aluminum oxide or silicon oxide coatings are applied when high moisture-barrier is required.
Polybutylene terephthalate crystallizes far more rapidly than PET; mold temperatures of 80–120 °C are used for PBT, while PET preform molds must remain cold to avoid haze. PBT offers better notch toughness and lower moisture absorption, but lower oxygen barrier and lower glass transition. Polyethylene naphthalate is a higher-barrier polyester with a glass transition near 120 °C and a melt temperature of 265–270 °C, used where oxygen barrier and thermal stability justify cost; it is outside standard PET mechanical recycling streams.
PETG is an amorphous copolyester in which 1,4-cyclohexanedimethanol replaces a portion of ethylene glycol. ISO 1043-1 classifies these copolyesters separately from homopolymer PET. PETG is selected for thick-wall extruded sheet and thermoformed trays because it does not crystallize during cooling and offers notched Izod impact of 9–12 kJ/m². Its tensile modulus is lower, 1900–2100 MPa compared with 2800–3100 MPa for PET, and its heat deflection temperature at 1.82 MPa is 63–70 °C. The material is therefore unsuitable for hot-fill applications above 65 °C, where heat-set PET or polycarbonate may be required.
Barrier data for PETG show higher oxygen and carbon dioxide transmission than oriented PET at equal thickness. This restricts PETG use in long-shelf-life oxygen-sensitive packaging. PETG extruded sheet is processed at lower melt temperatures than PET, but drying remains necessary; typical desiccant drying conditions are 65–70 °C for 4 h to <0.01 wt% moisture. Thermoforming of PETG sheet requires lower infrared heating intensity because amorphous sheet softens without crystallization, and edge-trim regrind can be incorporated at 20–50 wt% without loss of optical clarity.
Post-consumer recycling streams expose PET to polyvinyl chloride and other chlorinated polymers. PVC degrades at PET melt-processing temperatures above 260 °C, liberating hydrogen chloride that catalyzes PET hydrolysis and discoloration. Near-infrared sorting equipment separates PVC from PET bottles, and many bottle-to-bottle recycling operations reject flake with PVC contamination above 100 ppm. Metal contamination from aluminum caps must also be removed before melt filtration.
Unfilled PET is not recommended for continuous load-bearing service above 120 °C unless crystallized or heat-set. Amine-based additives, certain nucleating agents, and halogen-containing flame retardants can accelerate ester cleavage or corrode melt converting equipment; such additives require qualification before compounding. Food-contact PET is specified under FDA 21 CFR 177.1630 and European Commission Regulation 10/2011. Recycled PET intended for food contact in the European Union must meet the decontamination requirements of Regulation 2022/1616. Polyvinyl chloride contamination is considered a critical contaminant in mechanical recycling because of hydrogen chloride release during extrusion.
