A compounded polylactic acid (PLA)-based film resin designated INZEA F11 Flexible 40% Bio-Based Film Polylactic Acid is supplied for cast and blown film extrusion where a combination of renewable carbon content and ductile film behavior is required. The grade is formulated to contain 40% bio-based carbon as measured by ASTM D6866-21, with the remainder comprising non-bio-based flexible modifiers and processing aids. The numerical designation F11 identifies a flexible film grade within the INZEA polymer family and separates it from rigid injection-moulding grades and from higher-renewable-carbon film grades that exhibit lower tensile elongation at break. Film converters evaluate INZEA F11 for packaging structures where unmodified PLA fails by brittle fracture during unwind, flexing, or heat-sealing, and where finished-article renewable carbon content must be demonstrated through radiocarbon analysis rather than mass-balance accounting.

What specification values and compliance boundaries apply to INZEA F11?

Typical values from supplier technical documentation are listed in Table 1. The values are representative for 50 µm cast film unless otherwise stated and are not to be interpreted as release limits; variation across melt lots and film thicknesses is expected.

The resin-level bio-based carbon value should not be conflated with finished-film renewable content: printing inks, solventless laminating adhesives, and mineral fillers reduce the measured bio-based carbon of the converted article. Compliance with organic recovery schemes must be demonstrated on the finished article under EN 13432:2000 or ASTM D6400-21, including disintegration after 12 weeks and ecotoxicity testing according to OECD 208. Food-contact status is not automatically conferred by the resin supplier; conversion for direct food contact requires migration testing under FDA 21 CFR 175.300 or Regulation (EU) 10/2011 for the specific food simulant and film thickness.

Industrial compostability and bio-based carbon claims for INZEA F11 are governed by the following boundaries.

Thermal degradation and drying boundaries before extrusion

Before film extrusion, the resin must be dried to a moisture content below 0.025%. At relative humidity above 60%, exposed granules pick up surface moisture within 30–60 minutes; therefore a closed desiccant-dryer hopper with a dew point below -40°C is the minimum equipment configuration. Drying at 60–80°C for 4–6 hours is the supplier-recommended regime; higher drying temperatures may cause particle fusion in the hopper. The extruder feed throat is kept below 50°C to prevent premature sticking.

In the extruder, the temperature window is constrained by the melting endotherm near 150–160°C and by thermal degradation kinetics above 200°C. PLA chains undergo random scission and lactide reformation at elevated temperature; the zero-shear viscosity declines irreversibly and film gauge variation increases. A single-screw extruder with a moderate compression ratio of 2.5:1 to 3.0:1 and a barrel length of 30 L/D is used on production lines; barrier screws improve melt homogeneity at low screw speeds, but high-shear Maddock mixing sections should be avoided because excessive viscous heating creates local temperatures above the degradation threshold even when barrel set points remain below 195°C.

Barrel set points from feed to die are typically 150–160°C, 165–175°C, 175–185°C, and 180–195°C. Residence time beyond 15 minutes at melt temperature produces gels, yellowing, and a loss of melt strength. Shutdown and material-change procedures use purging compounds compatible with PLA; polyethylene purging is acceptable only if the line is subsequently flushed with a dedicated PLA-compatible purge to avoid interfacial incompatibility during restart. The apparent shear viscosity follows shear-thinning behaviour typical of PLA-based compounds. At 190°C, melt viscosity in the shear-rate range of 100–1000 s⁻¹ is relevant to extrusion dies; at low shear rates below 10 s⁻¹, the higher zero-shear viscosity contributes to die swell. Film processors monitor melt pressure before the screen pack as an indirect quality variable; pressure fluctuations greater than ±1.0 MPa at constant screw speed indicate feed instability, moisture contamination, or viscosity degradation.

When regrind is used, batch-to-batch melt pressure variation becomes measurable at addition levels above 20%; regrind must be dried under the same conditions as virgin resin and screened through a 1.5 mm mesh to remove film flakes that can cause feed-bridging. Edge-trim and slit-scrap regrind is typically reintroduced at 10–15% to maintain stable melt pumping. The material has been used on blown-film lines with die gaps between 0.8 mm and 1.2 mm; wider polyethylene die gaps reduce bubble stability because PLA-based melts exhibit lower elongational melt strength than low-density polyethylene. Bubbles are normally run with a blow-up ratio between 2:1 and 3:1 and frost-line height 200–400 mm above the die; the exact frost line depends on air-ring temperature and gauge. Cast-film lines allow slightly higher melt temperatures but require polished chill rolls at 20–30°C to prevent blocking.

The grade is converted into printed organic waste bags, carrier films, and packaging layers where compostability certification is required on the finished article. Seal initiation occurs at 85–95°C on a hot-bar or impulse sealer; seal strength is highly dependent on film gauge and dwell time. Corona treatment with a surface energy above 38 mN/m is applied for water-based ink and lamination adhesion; however, the treated surface may decay within 7 days in humid storage, requiring re-treatment before printing. The film form has been tested in industrial composting facilities with a thermophilic phase above 58°C; the polymer hydrolyzes and is mineralized by microorganisms. Published data for home composting conditions are limited; the grade is not generally certified for home compostability because lower temperatures and longer time scales do not guarantee full mineralization. A material certified to EN 13432:2000 is not automatically suitable for home compost schemes such as NFT 51-800 or AS 5810.

When INZEA F11 replaces conventional polyethylene in film conversion equipment

Conversion of a polyethylene film line to INZEA F11 requires reduced barrel temperatures and narrower die gaps; the same screw that processes linear low-density polyethylene at 200–230°C must be re-profiled for a melt temperature plateau near 185–195°C. The lower melt strength of the PLA-based compound limits maximum line speed in blown-film processes; bubble oscillation and draw resonance are observed when take-up speed exceeds the melt extension rate. In practice, film converters report that single-screw extruders with grooved feed zones maintain higher specific output, but torque limits at low melt temperatures are reached before barrel capacity is fully utilized. On a production line with a 45 mm single-screw extruder with 30 L/D and a 0.8 mm die gap, melt pressure fluctuations above ±1.0 MPa have been associated with feed-bridging of undried regrind in PLA-based compounds; the same failure mode applies to INZEA F11 if regrind moisture is not controlled.

The purge procedure is a critical operational boundary. Residual polyethylene or polypropylene in adapters and dies degrades under PLA processing conditions and can form char, which contaminates subsequent film. A complete line audit for dead spots in screen changers, melt pumps, and die manifolds is required before introduction of INZEA F11. Continuous backflush screen changers with 100–150 µm screens are used because PLA film is sensitive to melt contamination that appears as gel specks. Batch-to-batch melt mass-flow-rate variation in production lots is normally specified as a release window. When switching lots, the melt pressure can shift by 5–10%; operators compensate by adjusting screw speed rather than barrel temperature because the degradation threshold leaves little thermal headroom. This operational constraint is more severe than for polyethylene, where temperature can be increased to manage viscosity.

Differences from polyethylene are most evident in film mechanical properties. INZEA F11 exhibits higher stiffness than low-density polyethylene but lower dart impact at equal gauge; for packaging applications requiring abuse resistance, a thickness increase of 10–20% relative to polyethylene is frequently necessary unless a blending layer is used. The published data for this specific configuration is limited, and no universal thickness equivalency should be assumed. The film also has a service temperature boundary below the glass transition of PLA at 55–60°C; elevated-temperature washing, autoclaving, or hot-fill operations above this range cause dimensional distortion and seal failure.

Compared with unmodified PLA film grades, INZEA F11 shifts tensile failure from brittle fracture to ductile yielding. Unmodified PLA films typically show tensile elongation at break in the range of 2–10% under ISO 527-3:2018, whereas INZEA F11 is formulated to exceed 300%. The formulation trade-off is a lower modulus and a bio-based carbon fraction of 40% rather than the >90% typical for pure PLA. The product therefore competes not with rigid PLA for thermoformed trays but with PBAT-based flexible films that have excellent ductility but lower renewable carbon. Relative to PBAT films, INZEA F11 can raise the renewable carbon content of a compostable laminate while lowering some mechanical performance values such as tear propagation resistance; comparative data should be generated on the specific converting line because film orientation conditions dominate final properties.

Within the INZEA family, F11 differs from injection-moulding formulations by higher melt flow and flexibility. Grades designed for thermoforming may have higher rigidity and a bio-based carbon content above 40%; selection of INZEA F11 is appropriate only where film ductility is the controlling requirement. No single grade can simultaneously maximize renewable carbon and flexibility because the flexible modifiers are non-bio-based in this formulation. Compared with PHA films, INZEA F11 has lower renewable carbon and typically lower raw material cost; quantitative mechanical comparisons are outside public datasheet values. INZEA F11 is not an oxo-degradable additive system and does not fragment under aerobic soil; it is intended for industrial composting where thermophilic temperatures exceed 58°C. Store unopened bags in dry conditions at 15–30°C. Once opened, material should be consumed within 8 hours unless hopper dryers maintain 0.025% moisture. Prolonged storage above 30°C may cause pellet blocking, and exposure to high humidity prior to drying will increase the time required to reach processing moisture specification.