Polylactic Acid REVODE193

Thermoformed rigid food-contact packaging from REVODE193 is specified where clarity, surface gloss and compostability are required, while hot-fill resistance remains outside the unmodified resin boundary. The resin must be dried before sheet extrusion because molten PLA undergoes hydrolytic chain scission autocatalytically above the melt threshold. Drying in a desiccant hopper to 250 ppm residual moisture per ISO 15512:2019 is the control point for flat-die residence times below 20 min. A 75 mm single-screw extruder with 30:1 to 36:1 L/D and a low-shear barrier screw produces sheet at melt temperatures from 195°C to 215°C. The extrudate enters a vertical three-roll polishing stack; roll temperatures are held at 25°C to 45°C to suppress spherulitic nucleation and preserve contact clarity. Sheet of 0.3 mm to 0.8 mm is wound with an interleaf where surface blocking is observed during storage.

Thermoforming requires sheet surface reheating to 85°C to 95°C, which is above the PLA glass transition and below the onset of the cold-crystallization exotherm. Plug-assisted vacuum forming with pre-stretch plug temperatures between 60°C and 80°C allows an area draw ratio of approximately 3:1 on shallow trays without web tearing. Crystallinity remains low after forming unless a post-mould annealing step at 100°C to 120°C is added. Annealing raises the heat deflection temperature under 0.455 MPa load, measured by ISO 75-2:2013 Method B, but increases haze above 10% depending on wall thickness. Terminal articles are transparent clamshells, bakery trays, egg cartons, deli cups and produce punnets. Food-contact status is governed by European Regulation (EC) No 10/2011 Annex I; overall migration is limited to 10 mg/dm² under the applicable food simulant. For U.S. distribution, the grade-specific Food Contact Notification must be referenced, because PLA is not covered by 21 CFR 177.1520.

Values in the matrix are representative of PLA sheet-converting conditions; REVODE193-specific values should be confirmed against the grade datasheet and the converter’s line instrumentation.

What Limits Melt-Phase Clarity Retention in Double-Bubble BOPLA Film from REVODE193?

Double-bubble orientation of REVODE193 requires the primary cast web to be quenched into a largely amorphous state before solid-state stretching. The quench roll temperature is maintained at 20°C to 30°C, because slow cooling promotes spherulites that act as stress concentrators during transverse draw. The reheat zone in the orientation oven is limited to 75°C to 85°C; this window sits between the PLA glass transition at approximately 58°C and the onset of cold crystallization near 100°C as detected by differential scanning calorimetry under ISO 11357-2:2020. Machine-direction draw ratios between 3.0 and 4.5 and transverse draw ratios between 3.0 and 4.0 induce strain-hardening and improve tensile modulus, but the internal bubble pressure must be controlled within 0.2 MPa to 0.5 MPa to avoid local thinning in the bubble stalk.

Clarity loss in finished film is controlled more by orientation temperature than by additive chemistry. Haze measured by ISO 14782:2021 remains below 3% for 20 µm film when the orientation temperature is held in the lower half of the range, whereas operation at 90°C triggers haze above 5% due to stress-induced crystallization. The film is corona-treated to surface tension of 38 mN/m to 44 mN/m for flexographic and gravure ink adhesion. Terminal structures include twist-wrap windows, carton overwrap, produce bag laminations and print lamination films. Food-contact BOPLA film from REVODE193 must comply with European Regulation (EC) No 10/2011; migration testing under simulant A for hydrophilic foods and simulant D2 for acidic foods is required depending on contact category. Low coefficient of friction of 0.25 to 0.40 for vertical form-fill-seal machineability is obtained by adding 0.5 wt% to 1.0 wt% erucamide masterbatch, which migrates to the film surface over 24 h to 72 h.

Published data for REVODE193-specific bubble stability at draw ratios above 4.5 is limited. Converters running high-gauge thin film at elevated draw ratios typically co-extrude a thin amorphous PLA skin layer to restrict surface haze while maintaining the bulk mechanical properties of the oriented core.

Injection Moulding Processing Windows for REVODE193 at 3 mm Wall Thickness

Unmodified PLA near REVODE193’s melt-flow range is suitable for cold-runner injection moulding when the part wall is below 3 mm. Melt temperatures are set between 185°C and 210°C; exceeding 230°C accelerates hydrolytic chain scission even at residual moisture below 250 ppm. A two-stage reciprocating screw with a low-compression screw geometry and positive non-return valve is used to minimize adhesive wear at the check ring. Mould temperatures of 25°C to 40°C provide adequate surface finish for cutlery, but crystallization in the core is arrested, leaving the part with heat deflection temperature below 55°C at 0.455 MPa load per ISO 75-2:2013 Method B.

Thin-wall containers benefit from fast injection velocities of 100 mm/s to 250 mm/s to avoid premature freeze-off at the gate. Hold pressure is set at 50% to 70% of injection peak to reduce gate stress. Notched Izod impact by ISO 180:2023/1A for unmodified PLA is typically below 3 kJ/m²; therefore cutlery must include ribbing at the handle transition. If regrind content exceeds 30%, tensile strength retention drops unless the regrind is dried to below 150 ppm and blended with 0.2 wt% chain extender to restore melt viscosity. Terminal products include cafeteria trays, soup spoons, portion cups, condiment containers and single-use medical trays. Compliance includes EU Regulation (EC) No 10/2011 for food-contact cups and cutlery; for U.S. distribution, grade-specific FCN should be referenced because PLA does not fall under 21 CFR 177.1520.

For fused filament fabrication feedstocks, REVODE193 is compounded into round monofilament through a single-screw extruder fitted with a melt pump and a two-axis laser diameter gauge. The target diameter is 1.75 mm with tolerance ±0.05 mm; ovality is limited to 0.03 mm across the spool. Water content before extrusion must be below 250 ppm; dried pellets are fed under dry air with dew point below -40°C. Melt temperature at the die is 190°C to 210°C, and the water bath is set at 40°C to 60°C to control diameter variation. The filament is spooled at 10 m/min to 30 m/min; line speed and extruder screw speed are linked through diameter feedback to maintain dimensional tolerance.

Printing with REVODE193-based monofilament uses a nozzle temperature of 200°C to 220°C and a bed temperature of 50°C to 60°C. Print speed is held at 40 mm/s to 60 mm/s for 0.4 mm to 0.8 mm layer heights. Internal stress and moisture cause bubbling at the nozzle; filament should be dried at 45°C for 4 h before use. Tensile properties of printed specimens per ISO 527-2:2012 are lower than injection-moulded samples because interlayer adhesion is the limiting plane. Terminal products include orthotic trial models, assembly jigs, educational prototypes and lost-pattern molds where compostability is not the primary requirement but solvent-free processing is preferred.

When CO₂-Laden Melt Exits the Foaming Die Below the Solubility Pressure Threshold

Foam extrusion of REVODE193 uses a tandem line with a primary 50 mm extruder at 32:1 L/D for plastication and a secondary 90 mm extruder at 24:1 L/D for cooling. The first extruder melts the resin at 190°C to 210°C; supercritical or liquid carbon dioxide is injected at 5 wt% to 7 wt% through a high-pressure port at 15 MPa to 20 MPa. Dissolution requires a static mixer or segmented screw elements; if pressure drops below 7 MPa before the die, premature nucleation creates large cells, surface defects and collapsed foam ribs.

Nucleation is controlled with talc at 0.5 wt% to 1.5 wt% with particle size below 5 µm. Die temperature is reduced to 140°C to 160°C to increase melt strength, but die pressure must remain above gas saturation pressure during the entire run. The resulting foam sheet typically has density of 200 kg/m³ to 600 kg/m³, cell size 100 µm to 400 µm, and open-cell content below 10%. Published data for REVODE193-specific foam densities below 150 kg/m³ is limited; chain extension is generally required to achieve stable low-density structures because linear PLA has insufficient melt elasticity to resist cell coalescence at high expansion ratios.

Terminal products include cushioning inserts, non-food logistics foam, void-fill sheet and structural packaging corners. Compliance with EU Regulation (EC) No 10/2011 is required for direct food use; for non-food logistics foam, the principal requirement is absence of residual blowing agent above permissible exposure limits and conformance to the packaging waste directive EN 13432 where compostability is claimed.

Spunbond nonwoven converting of REVODE193 requires tighter thermal control than polypropylene because PLA solidifies rapidly and the calender bonding window is narrow. Melt spinning uses extruder zones from 200°C at the feed throat to 230°C to 240°C at the spin beam. The spinneret holes are 0.3 mm to 0.5 mm in diameter with length-to-diameter ratio of 4:1 to 8:1. Quench air at 18°C to 22°C and velocity 0.3 m/s to 0.6 m/s produces filament diameters of 15 µm to 25 µm. The web is bonded on a heated engraved calender at 130°C to 145°C with bond area 15% to 25% and nip pressure 60 N/mm to 120 N/mm.

Bond strength is sensitive to calender temperature; below 130°C the bond points remain weak, while above 145°C the filaments collapse into brittle film-like zones. Web tensile strength measured by ISO 9073-3:2023 for 30 g/m² fabric typically reaches 25 N/5 cm to 50 N/5 cm in the machine direction and 10 N/5 cm to 30 N/5 cm cross direction. This anisotropy is suitable for hygiene top sheets and agricultural mulching. For hygiene applications, migration of additives must comply with EU Regulation (EC) No 10/2011 and REACH; any intentionally added substance above 0.1% w/w must be declared and substantiated.

Agricultural mulching webs are produced on the same beam configuration with wider die and reduced calender pressure to preserve open area for water penetration. The nonwoven degrades under composting conditions according to EN 13432:2000 if the full article is certified. Terminal products include spunbond mulching film, hygiene acquisition layers, filtration support layers and crop cover fabric.