ECOPLAN -DURA EN100 Flexible Heat Resistant Microwavable Polylactic Acid is a poly(lactic acid)-based thermoplastic compound supplied for injection moulding, sheet extrusion, and thermoforming of food-contact packaging that must tolerate short microwave reheating. The grade is formulated to reduce the brittleness of standard PLA and to shift the thermal service limit above the range at which amorphous PLA begins to creep under load. It is not a polyolefin drop-in; successful conversion requires adjustment of drying, mould temperature, runner geometry, and wall thickness. The EN100 identifier positions the product within the supplier’s durability and heat-resistance series, but the exact heat deflection temperature, elongation at break, and melt flow rate are batch-specific and must be obtained from the supplier’s certificate of analysis. The processing and performance data presented below are compiled from published PLA compound behaviour and from production-scale moulding and extrusion experience; they do not replace the grade-specific technical data sheet.

How Does Heat Resistance in ECOPLAN -DURA EN100 Differ From a Standard PLA Homopolymer?

Standard amorphous PLA homopolymer has a glass transition near 55–60°C and a heat deflection temperature under ISO 75-2:2013 at 0.45 MPa in the same range. That thermal profile is inadequate when a lid or tray carries a hot food load above 70°C. Heat-resistant PLA compounds are produced by nucleation, stereocomplex blending, or post-mould annealing to increase crystalline content and raise the Vicat softening point measured under ISO 306:2022. The EN100 suffix indicates a heat-resistant flexible grade; however, published data for this specific configuration is limited, and design release values should be taken from the supplier’s technical data sheet.

Differential scanning calorimetry under ISO 11357-1:2016 and ISO 11357-3:2018 is used to characterise the glass transition, cold-crystallisation exotherm, and melting endotherm. A low cold-crystallisation onset indicates that hot mould temperatures will be required during injection moulding to develop the intended crystalline network. In microwave reheating, the polymer is heated mainly by conduction and convection from the food rather than by direct dielectric absorption. Localised oil and sugar pockets can exceed 100°C while the bulk aqueous phase remains below boiling. Qualification therefore requires instrumented food simulant tests that record maximum part surface temperature, deformation under lid load, and migration after repeated cycles. Heat distortion testing alone is not sufficient to certify a microwavable part.

Flexibility modification in PLA compounds is usually achieved with biodegradable aliphatic-aromatic copolyester impact modifiers or citrate/ester plasticisers. The tensile modulus under ISO 527-2 declines relative to unmodified PLA by a factor that depends on modifier loading. Notched Izod impact under ISO 180:2019 may increase from the brittle regime below 5 kJ/m² to a ductile regime above 10 kJ/m², but the exact change for EN100 is supplier-specific. The flexible phase can also reduce the concentration of crystalline regions at the surface if mould temperatures are too low; therefore, the heat-resistance claim is coupled to processing conditions rather than to the resin alone.

Drying, Melt Temperature, and Screw Configuration on Production-Scale Extruders

Moisture control is the primary processing constraint. PLA undergoes hydrolytic chain scission in the melt if residual moisture exceeds approximately 250 ppm. Pellets must be pre-dried in a desiccant dryer at 80°C for 4–6 h or dried in-line to a dew point below -40°C. At factory relative humidity above 60%, machine hoppers and open gaylords should be blanketed with dried air or nitrogen. Residual moisture should be confirmed before start-up by Karl Fischer titration or a calibrated online moisture analyser.

On a co-rotating twin-screw extruder with an L/D ratio of 28:1–40:1, barrel zone set points typically range from 160°C to 200°C. Melt temperature at the die should not exceed 210–220°C for normal cycles; excursions above 230°C accelerate lactide formation and discolouration. For injection moulding, a low-compression screw with a compression ratio of 2.5:1–3:1 and a back pressure of 5–15 bar is appropriate. Shot size should be kept between 30% and 70% of barrel capacity. Thin-wall parts with flow length-to-wall thickness ratios approaching 150:1 may require hot mould temperatures of 80–110°C to promote crystallization and maintain ejection rigidity. Mould temperatures below 40°C tend to freeze an amorphous skin, reduce heat resistance, and increase warp after demoulding. Cavity pressure sensors are recommended in multi-cavity tools because melt-viscosity variation among flexible PLA batches can shift fill balance and produce dimensional drift in microwave lids.

If the material is converted as a pre-compound, incoming pellet uniformity should be checked by melt flow rate under ISO 1133-1:2022 at 190°C/2.16 kg or 210°C/2.16 kg. Values must not be compared across different temperature and load conditions. Batch-to-batch MFR variability greater than 15% can indicate hydrolytic degradation or modifier dispersion faults. Production-scale extrusion lines with vacuum venting below 50 mbar absolute are used to strip residual moisture and lactide; loss of vent vacuum produces surface splay and gas bubbles in sheet or moulded parts.

Food-contact status for ECOPLAN -DURA EN100 is not a universal property. Compliance is established through the supplier’s United States Food Contact Notification, the EU Declaration of Compliance under Commission Regulation (EU) No 10/2011, and applicable national food-contact standards such as GB 9685 in China. Overall migration must not exceed 10 mg/dm² or 60 mg/kg under the prescribed simulants and test conditions. Because PLA is hydrolytically sensitive in aqueous simulants at elevated temperature, migration testing should be performed at the intended time–temperature profile rather than only the standard 10-day 40°C condition. Industrial compostability is evaluated under EN 13432:2000, ASTM D6400-19, and ISO 17088:2021; these standards do not confer home compostability or marine biodegradation. The microwave-use designation is a thermal fitness claim, not a food-contact clearance. It must be supported by final-part tests with representative food simulants and by hot-spot mapping at the intended microwave power output.

Migration kinetics in polymer matrices depend on molecular mobility near the glass transition. In flexible PLA grades, impact modifiers and plasticisers can raise the diffusion coefficient for low-molecular-weight additives at temperatures above 60°C. Therefore, compliance certificates for microwave service should be reviewed for the specific additive package, and new tool surface or regrind ratios above 20% should be revalidated because regrind may alter migration behaviour and heat resistance.

When ECOPLAN -DURA EN100 Replaces Polypropylene in Short-Contact Microwave Service

Polypropylene is the incumbent material for microwave lids and trays because it typically exhibits a heat deflection temperature of 90–110°C at 0.45 MPa under ISO 75-2:2013, tensile elongation above 100% under ISO 527-2, and very low moisture sensitivity. ECOPLAN -DURA EN100 is selected where the part owner requires a PLA-based, compostable or bio-based alternative and accepts a narrower thermal and mechanical operating window. The replacement is not a simple resin swap.

Standard polypropylene living hinges with a thickness of 0.25–0.4 mm generally do not transfer directly to PLA-based compounds. Hinge thickness should be increased to 0.4–0.6 mm, the hinge radius enlarged, and repeated flex testing performed at the intended microwave exit temperature. Flow length-to-wall thickness ratios should be lowered below 150:1 because PLA melt strength and thermal conductivity differ from polypropylene. Hot mould temperatures required for crystallisation increase cooling time and may raise cycle time by 15–30% relative to PP. Dimensional stability in thin-wall parts should be validated with injection-compression moulding or in-mould annealing to control warp. Clamp force requirements should be estimated from cavity pressure measurements rather than from PP historical data because lower melt thermal diffusivity can alter solidification rate and peak injection pressure.

Microwave service should also account for the lid or tray thickness distribution. In PLA compounds, chilled amorphous skins can develop at the mould surface while the core crystallises; this skin–core structure produces differential shrinkage and can warp after reheating. Annealing fixtures or post-mould crystallisation at 80–100°C for 10–30 min may be required to stabilise geometry before microwave testing. The annealing step is not required for polypropylene and represents an additional cost.

Operational boundaries for ECOPLAN -DURA EN100 must be stated. The material is not intended for continuous oven use, retort, steam sterilisation, or dishwasher cycles unless the finished part has been validated at the corresponding temperature–time profile. The compound should not be processed with amine-based additives or strongly alkaline concentrates because these species can accelerate polymer degradation and reduce heat resistance. Storage should be in sealed moisture-barrier packaging at relative humidity below 60%; opened packaging exposed for more than 8 h should be re-dried before moulding. Equipment should be purged with a low-melt-index polyolefin or a commercial purge compound before shutdown to avoid stagnant melt zones above 200°C. Regrind levels should be limited to 20–30% or the supplier’s validated maximum; higher regrind addition can lower melt viscosity and heat distortion. These limitations are class-level boundaries for flexible heat-resistant PLA compounds; the manufacturer’s grade-specific technical data sheet and application test report form the binding specification for any commercial part.