Rigid sheet extrusion followed by plug-assisted thermoforming is one of the few downstream routes where the rheological demand for sag resistance and the mechanical demand for hinge-fold durability intersect on the same production line. On sheet lines running 500–700 kg/h, the impact-modified PLA is pre-dried in desiccant dryers at 80°C for 4 h to a residual moisture content below 0.010% (100 ppm) because hydrolysis at melt temperatures above 190°C reduces molecular weight and produces surface splay on polished rolls. The governing food-contact documentation for this application includes FDA Food Contact Notification FCN 178 for polylactic acid, Commission Regulation (EU) No 10/2011 as amended with an overall migration limit of 10 mg/dm², EN 13432:2000 for industrial compostability, and ASTM D6866-21 Method B for bio-based carbon verification. Sheet extrusion is performed on a single-screw extruder with an L/D ratio of 30:1, a barrier screw equipped with a melt pump, flat die temperature 200–210°C, and roll stack temperatures 35–50°C; the sheet gauge is controlled between 0.30 mm and 0.60 mm with transverse gauge variation below ±0.02 mm. The compound is fed at 100% pelleted material, with clean post-industrial regrind limited to 25 wt% of the total melt stream because recycled PLA reduces extensional viscosity and promotes sagging in the thermoforming oven. If a processor blends with unmodified PLA for cost reduction, the impact-modified compound should remain at or above 70 wt% to keep clamshell hinge impact above 40 J/m when measured per ASTM D256-10. The thermoforming step requires sheet surface temperature held at 70–80°C, below the cold-crystallization onset of 95–105°C, and plug temperature maintained at 70–90°C with a low-thermal-conductivity plug material to reduce sticking. Terminal product types include hinged clamshells for refrigerated deli items, fruit punnets, sushi trays, and refrigerated prepared meal bases; draw ratios are kept below 3:1 on multi-cavity rotary tools unless assisted pre-stretch from plug geometry is validated. The impact-modified formulation raises notched Izod impact relative to unmodified PLA from approximately 16 J/m to 40–80 J/m, which is the principal mechanical advantage for clamshell hinges and tray corners at refrigerated temperatures.

What Limits Preform Reheat Stability When Moulding Cold-Chain Bottles from Impact-Modified PLA?

Because impact-modified PLA has low melt strength relative to PET, the injection blow moulding route is constrained by the preform reheat window rather than by injection pressure alone. Preforms are injection moulded from 100% compound on a two-stage injection blow moulding system; qualified regrind from rejected preforms may be incorporated at up to 15 wt% only if the regrind was not exposed to moisture above 0.025% (250 ppm) before re-drying. Melt temperature at the preform injection nozzle is controlled at 200–220°C, the hot runner manifold at 210°C, and the preform mould is chilled to 10–15°C to reduce spherulite formation; injection pressures of 800–1,200 bar are typical for 24–48 cavity preform tools. Reheat is performed in infrared ovens with quartz lamps tuned to 3.0–4.5 µm wavelengths, and surface temperature is held at 85–95°C because a ±5°C deviation measurably shifts the blow-up ratio and sidewall thickness distribution by more than 20%. Blow moulding is completed at 10–12 bar into chilled moulds at 35–40°C. Compliance for food-contact bottles includes FDA Food Contact Notification FCN 178, Commission Regulation (EU) No 10/2011 as amended, and the overall migration limit of 10 mg/dm²; mechanical evaluation includes ASTM D638-14 for tensile yield, ASTM D256-10 for notched Izod impact at 4°C, and ISO 8295 for coefficient of friction on sidewalls. Terminal product types are 250–500 mL single-serve cold-chain juice and dairy beverage bottles filled below 4°C; carbonation is limited to below 2.0 volumes because PLA permeation and creep under pressure are unsuitable for high-carbonation soft drinks. Published data for this exact RTP grade in injection blow moulding is limited, so preform reheating parameters must be verified against the lot certificate and mold-flow simulation using rheological data generated per ISO 1133-1:2022 at 210°C/2.16 kg.

Injection-moulded disposable cutlery produced from this compound runs on high-speed cells with 180–250 t clamp force and 32–64 cavity hot-runner tools. The material is processed at 100% pellet feed; if a cost-reduction blend with unmodified PLA regrind is used in the same melt stream, the regrind fraction is limited to 20 wt% because higher fractions reduce spoon bowl stiffness and fork tine fracture resistance when tested per ASTM D790-17. Colour masterbatch or processing aid addition is kept at 1–2 wt% and the carrier resin must be PLA-based to preserve EN 13432:2000 compostability. Melt temperature is maintained at 190–210°C, mould temperature 25–40°C, injection speed 150–250 mm/s, holding pressure 600–1,000 bar, back pressure 5–10 bar, and cooling time 10–18 s depending on wall thickness. The compliance file includes FDA Food Contact Notification FCN 178, Commission Regulation (EU) No 10/2011 as amended, EN 13432:2000, and ASTM D6866-21 Method B for bio-based carbon content. Terminal finished product types are 4–6 g forks, spoons, knives, and sporks for cold and warm foodservice up to 80°C, with the caveat that exposure to boiling water or microwaves is outside the operational boundary because heat deflection temperature under 0.455 MPa is typically 52–58°C per ASTM D648-18. The impact-modified grade is selected over conventional PLA because cutlery under bending load at tine roots shows improved resistance to crack initiation; notched Izod values are typically 40–80 J/m per ASTM D256-10, while flexural modulus remains in the 2.5–3.5 GPa range.

Extruded Rollstock for Foodservice Cup Lids and Tamper-Evident Portion Cups

Rollstock extrusion of impact-modified PLA for foodservice cup lids uses a flat die at 800–1,200 mm effective width with die gap set to 0.5 mm and air knife polishing rolls at 40–55°C. The compound is run at 100% pellets, with edge trim and reject rollstock reintroduced at a maximum of 20 wt% through a closed-loop granulator and desiccant re-dryer because moisture uptake above 0.010% (100 ppm) reduces heat-seal strength and produces die-lip buildup. Addition of antiblock masterbatch is limited to 1–2 wt% using a PLA carrier; the masterbatch must carry the same FDA Food Contact Notification FCN 178 and Commission Regulation (EU) No 10/2011 migration documentation. Sheet thickness is controlled between 0.20 mm and 0.40 mm, and post-extrusion corona treatment is set to 38–42 dyn/cm for printing and heat-seal lacquers. Compliance for this application includes FDA Food Contact Notification FCN 178, Commission Regulation (EU) No 10/2011 as amended, EN 13432:2000, and ASTM F88/F88M-21 for seal strength on finished lidding pairs. The downstream process consists of in-line thermoforming of lid skirts and scoring; punch-and-die sets are heated to 60–70°C to prevent micro-cracking at score lines. Terminal product types are 80 mm and 95 mm rigid cup lids for PLA-lined cold beverage cups, portion cup lids for dairy desserts, and tamper-evident dairy sleeve lids. The operational boundary is cold-chain use; exposure above 55°C under load causes creep and lid doming.

When Single-Serve Capsule Walls Drop Below 0.5 mm, Melt Flow and Gate Freeze Compete

Single-serve coffee capsule bodies and lids manufactured from impact-modified PLA are moulded in 16–32 cavity hot-runner tools with wall thicknesses of 0.4–0.8 mm. The material is processed at 100% pellets; hot-runner purgings and short shots are re-introduced as regrind at up to 15 wt% only after sorting to eliminate charred resin and moisture exposure above 0.015% (150 ppm). Melt temperature is set at 210–230°C, mould temperature 30–45°C, injection pressure 1,000–1,500 bar, holding pressure 600–900 bar, and cooling time 6–10 s. The gate must freeze before holding pressure is released; otherwise, voids occur at the capsule rim seal, reducing burst resistance. Compliance documentation includes FDA Food Contact Notification FCN 178, Commission Regulation (EU) No 10/2011 as amended, EN 13432:2000 for compostable capsule systems, and ASTM D1238-20 for melt flow rate measured at 210°C/2.16 kg. Terminal product types are 5–7 g coffee capsule bodies and lidding rings for compostable pod systems; brewing temperatures of 85–95°C are tolerated only for short contact times because the PLA compound softens above 55°C. The application is structurally feasible only when the capsule body is supported by an outer shell or brew chamber; published data for this specific RTP grade in capsule geometry is limited, so mold-flow analysis must be calibrated against capillary rheometry data rather than generic PLA values.

Dry-Food Jar Extrusion Blow Moulding with a 10 Wt% Regrind Loop

For dry-food jars below 500 mL, extrusion blow moulding of impact-modified PLA is run on a 20:1 L/D extruder with 40–60 mm screw diameter and an accumulator head set to 190–215°C. The compound is fed at 100%; post-consumer regrind is not used in the food-contact layer, and post-industrial regrind is limited to 10 wt% because die swell consistency and parison sag become variable at higher recycled content. Blow moulding is performed at 6–9 bar into moulds maintained at 30–40°C, with drop time 2–5 s depending on jar height. Compliance includes FDA Food Contact Notification FCN 178, Commission Regulation (EU) No 10/2011 as amended, and EN 13432:2000. Terminal product types are 150–500 mL dry-food jars for tea, spices, and powdered beverage mixes; hot fill is restricted to below 55°C because sustained wall load at higher temperatures causes creep and thread deformation.