Sheet extrusion of VG7213 into cast sheet between 1.2 mm and 2.5 mm thickness is the first unit operation in a plug-assisted pressure-forming line for high-heat PLA food-contact articles. The resin is dried to a residual moisture level below 250 ppm with a desiccant dryer delivering a dew point of −40 °C or lower; hydrolysis in the barrel raises melt flow rate and deposits lactide on forming tool surfaces. Melt temperature at the flat die is held at 200 °C to 220 °C. The sheet is reheated to 95 °C to 120 °C and formed on aluminium tools maintained at 80 °C to 100 °C with plug assist and cavity pressure between 0.4 MPa and 0.8 MPa. Because unannealed PLA sheet has a heat deflection temperature below 60 °C under 0.45 MPa when measured according to ASTM D648-16, formed parts are transferred to a holding jig at 90 °C to 110 °C for 10 min to 30 min to develop crystallinity. The terminal articles are hot-fill condiment cups, portion trays and drink-through lids intended for short contact with media at 85 °C to 90 °C; continuous exposure to boiling water or retort conditions above 100 °C is outside the semi-durable service boundary. Food-contact conformity must be established under EC 10/2011 with an overall migration limit of 10 mg/dm² and, in the United States, a substance-specific Food Contact Notification; PLA does not fall under FDA 21 CFR 177.1520.

Where line speed requires faster crystallization during the forming cycle, a masterbatch of 1.0 wt% to 3.0 wt% high-purity talc or 1.5 wt% to 4.0 wt% poly(D-lactide) stereocomplex can be compounded into the sheet feedstock. The addition raises flexural modulus but reduces notched Izod impact, so the ratio is fixed by the end-of-line crush test for lidding fit. Sheet gauge variation across the web is controlled to ±0.05 mm. The plug-assist speed and plug temperature are set against the crystallization onset temperature determined by differential scanning calorimetry per ISO 11357-3:2018. If the plug is below 70 °C, the contact area chills below the forming window and generates stress whitening in the final lid hinge. If the plug exceeds 120 °C, premature sticking and uneven wall thinning occur. Reclaimed edge trim is reintroduced at no more than 20 wt% without additional drying; higher regrind fractions reduce melt strength and enlarge pinhole counts.

What Distinguishes a Viable Annealing Window for Injection-Moulded High-Heat PLA?

Injection moulding of VG7213 occupies a narrow thermal interval because the crystallization half-time near 100 °C determines whether the frozen skin layer can reach adequate conversion before demoulding. A mould temperature of 95 °C to 105 °C is held with heated water or oil units. If the tool surface drops below 90 °C, the part remains largely amorphous and the heat deflection temperature under 0.45 MPa remains below 60 °C per ASTM D648-16. If the tool surface exceeds 110 °C, cycle time increases and the part can stick in the cavity. The practical mould temperature window is therefore ±5 °C around 100 °C. Melt temperature is set from 190 °C to 210 °C, injection velocity from 50 mm/s to 150 mm/s, packing pressure from 60 MPa to 100 MPa, and barrel residence time below 6 min to prevent lactide regeneration. Part weight stability is monitored over 30 cycles with a tolerance of 0.2% to confirm gate freeze and packing uniformity. After ejection, parts are placed in an annealing jig at 100 °C to 110 °C for 20 min to 40 min. The jig applies 0.1 MPa to 0.3 MPa contact pressure to reduce warpage; parts with wall thickness variation greater than 0.3 mm or unsupported flat sections longer than 40 mm show bowing greater than 1.0 mm after annealing.

The terminal parts are reusable takeaway containers, dry-appliance access panels and snap-fit clips that do not carry continuous hot-water flow. Compliance for electrical enclosure components is limited to UL 94 HB unless a separate flame-retardant masterbatch is used; neat PLA is not rated V-2 and cannot be claimed for glow-wire requirements under IEC 60695-2-11 above 650 °C without testing. Mechanical properties are determined on ISO 294-1 plaques: tensile modulus and yield stress per ISO 527-2:2012, flexural modulus per ISO 178:2019, and notched Izod per ISO 180:2019. For applications with repeated dishwashing, stress-cracking after 50 cycles at 65 °C must be evaluated because PLA undergoes hydrolysis in aqueous detergent media; published data for VG7213 in this specific configuration is limited. A processing modification of 0.5 wt% to 1.5 wt% multifunctional epoxy chain extender is used only when regrind exceeds 30 wt%; higher addition raises melt viscosity and can shift the melt flow rate outside the injection window per ISO 1133-1:2022.

For staple fibre spinning lines processing VG7213, the polymer is dried to below 200 ppm moisture and extruded through a manifold with 40 µm to 60 µm filtration at melt temperatures of 190 °C to 210 °C. The spinneret has hole diameters from 0.3 mm to 0.5 mm, and the filaments are quenched with air at 18 °C to 25 °C before drawing at a ratio of 2.5:1 to 4.5:1. Drawn fibres show a tenacity of 2.0 cN/dtex to 3.5 cN/dtex when tested by ISO 5079, and after heat setting at 110 °C to 125 °C the dry heat shrinkage is held below 5% at 100 °C per ASTM D2259. The terminal products are nonwoven interlinings for shirt collars and shoe linings that must survive ironing at 110 °C without curling; continuous exposure to water above 60 °C combined with mechanical load induces hydrolytic embrittlement. A spin finish of 0.3 wt% to 0.8 wt% antistatic oil is applied before drawing; higher finish levels reduce fibre-to-fibre friction and create drafting instability on carding machines. Compliance for textile contact is based on OEKO-TEX Standard 100 annex four product class I/II, with batch-specific test reports required for pH, extractable antimony and residual lactide.

When an Annealed PLA Tool Is Used in Low-Temperature Vacuum Forming

Filament made from VG7213 is extruded through a single-screw line with L/D 24:1 to 36:1, a melt pump, and a laser diameter gauge controlling filament diameter at 1.75 mm ±0.03 mm or 2.85 mm ±0.05 mm. The feedstock is dried to 200 ppm moisture or lower; wet filament generates surface bubbles and diameter spikes above 0.08 mm. In fused deposition modelling, the melt temperature is set between 200 °C and 220 °C, the build plate at 60 °C to 80 °C, and the chamber is kept below 45 °C to avoid thermal warping. Printed parts are then annealed in a convection oven at 80 °C to 100 °C for 2 h to 6 h inside a packed powder bed or constrained fixture to maintain flatness; annealing raises the usable tool surface temperature but also produces anisotropic shrinkage of 0.3% to 0.8% along the print axes. The terminal tooling is limited to low-temperature vacuum forming against thin-gauge PETG or polystyrene sheet with surface temperatures below 90 °C; published data for VG7213 used as a tool surface against heated sheet above this limit is limited. The formulation for this route may include 0.2 wt% to 0.5 wt% internal release or processing aid, but addition above 0.5 wt% lowers interlayer adhesion and reduces tensile strength through the Z axis. Compliance is derived from REACH (EC) No 1907/2006 and RoHS 2011/65/EU as amended by (EU) 2015/863; no SVHC is expected above 0.1 wt% in the neat grade, but pigmented masterbatches must be screened separately for lead, cadmium and phthalate plasticizers.

Where aqueous dispersion coatings show slow heat-seal set times on unprimed board, VG7213 can be extrusion-coated directly onto paperboard in coating weights from 25 g/m² to 45 g/m². The melt temperature at the slot die is held at 210 °C to 240 °C, the air gap is set between 100 mm and 200 mm, and the chill roll is maintained at 15 °C to 25 °C to freeze the coating before penetration into the fibre. The paperboard surface is corona-treated to 38 mN/m to 42 mN/m immediately before contact; a lower surface energy reduces adhesion and creates pinholes at crease points. Line speed is typically 80 m/min to 200 m/min for board from 350 g/m² to 500 g/m²; higher speeds demand higher melt temperature and increase lactide fuming. The coated board can be converted into hot-beverage cups and portion packets that are filled at 80 °C to 90 °C and consumed within 30 min to 60 min. The terminal package is not intended for boiling water, retort, or alcohol above 15 vol%. The structure must meet EC 10/2011 overall migration ≤10 mg/dm², and the cup seams are tested for leakage by ASTM F2096 modified for paperboard. Compostability claims for the total package require separate certification under EN 13432 or ASTM D6400 because the paper fibre, adhesives and printing layers must also disintegrate within 12 weeks.

For extrusion coating, a tie layer of 5 wt% to 10 wt% maleated PLA or ethylene copolymer is used only when board release strength drops below 2 N/15 mm in a 180° peel test according to ISO 8510-2; the tie layer must not compromise the overall migration limit. Process stabilizer at 0.1 wt% to 0.4 wt% is added to suppress lactide reformation during long runs exceeding 4 h. This addition is withheld when the coated board enters food-contact compliance because the stabilizer must be covered by the same Food Contact Notification or positive list.

Thick-Wall Jar Moulding and Crystallisation Annealing for Personal-Care Closures

Thick-wall cosmetic jars require packing-pressure profiles that delay gate freeze until volumetric shrinkage reaches 0.5% to 1.2% of cavity volume. For wall thicknesses of 2.5 mm to 5.0 mm, VG7213 is injected at 190 °C to 205 °C with a mould temperature of 90 °C to 105 °C, a filling time of 0.8 s to 2.5 s, and a holding time of 10 s to 30 s. The thick section creates a low cooling rate near the core; without annealing, the core remains amorphous and the jar can soften at 55 °C to 60 °C. Post-moulding annealing at 100 °C to 110 °C for 30 min to 60 min in a constrained nest raises the heat deflection temperature under 0.45 MPa to 90 °C to 120 °C for short peaks. The terminal articles are cream jars and snap-fit caps for dry personal-care formulations; they are not recommended for continuous contact with low-pH exfoliating acids above 45 °C because acidic hydrolysis accelerates molecular weight loss. A formulation modification of 1.0 wt% to 3.0 wt% talc nucleant or 1.5 wt% to 4.0 wt% PDLA masterbatch is used to shorten cycle time; the talc variant raises flexural modulus and reduces gloss, while the PDLA variant preserves clarity but increases viscosity.

Compliance for personal-care packaging is based on EC 1907/2006 REACH for SVHC below 0.1 wt% and EC 1223/2009 for the final cosmetic product responsibility; the jar itself is not a cosmetic product, but extractables testing in simulant D1 per EC 10/2011 is applied when the package is marketed for dual food/cosmetic use. Compatibility screening at 40 °C for 7 days in filled jars is required for formulations containing limonene, geraniol, or benzyl alcohol because these terpenes and aromatic alcohols can plasticize PLA and reduce drop height at failure by more than 30% when tested by ASTM D5276-19. The empty jar wall thickness tolerance is maintained at ±0.1 mm to avoid sink marks and annealing distortion.