INZEA F13 is a blown/cast film flexible packaging polylactic acid (PLA) grade supplied as cylindrical pellets for blown film and cast film conversion. The product is intended for use on conventional single-screw extruders with general-purpose polyolefin screws, provided that barrel temperature profile, die geometry, and drying hardware are adjusted for PLA rheology. Melt flow index measured at 190 °C with a 2.16 kg load according to ISO 1133-1:2022 typically lies between 2 and 6 g/10 min; material density is approximately 1.24 g/cm³ as determined by ISO 1183-1:2019. The grade is formulated to improve melt strength during bubble formation relative to unmodified injection-moulding PLA, and it is specified for compostable shopping bags, organic waste liners, garment bags, and flexible overwrap where industrial compostability is required. The numeric grade designation separates this film-specific product from rigid thermoforming and injection-moulding grades within the same biopolyester portfolio. Industrial compostability is assessed under EN 13432:2000/AC:2005; certification must be confirmed for the finished article, including adhesives, inks, and barrier coatings.

What Specification Envelope Applies to Film-Forming and Mechanical Performance?

Because PLA film properties are strongly dependent on thickness, orientation, and plasticizer content, specification values are defined on conditioned film rather than pellets. The following ranges represent the general envelope for a 25 µm monolayer cast film produced from PLA-based flexible packaging grades; batch-specific certificates of analysis for INZEA F13 should be consulted for compliance and may differ according to additive package. Tensile modulus according to ISO 527-3:2018 generally falls between 2,500 and 3,500 MPa. Tensile strength at break measured under ASTM D882-18 is commonly reported between 40 and 60 MPa. Elongation at break is formulation-dependent: unplasticized PLA film may exhibit 2% to 10%, while flexible film grades containing approved biodegradable plasticizers can reach 100% to 250%; published data for this specific configuration is limited when the additive package is proprietary.

Thermal analysis by differential scanning calorimetry according to ISO 11357-2:2020 typically shows a glass transition between 55 and 60 °C and a melting endotherm between 145 and 160 °C. The cold crystallization exotherm may appear when cooling is too slow; cast film rolls with excessive crystallinity exhibit increased haze and reduced heat-seal strength. Surface tension after corona treatment is typically measured at 38–42 mN/m according to ASTM D2578-17 before printing; treatment is applied inline because PLA surface energy decays with time.

On production lines, the principal process conflict arises from the narrow gap between melt strength and hydrolytic degradation. PLA melt viscosity decreases rapidly when the melt temperature exceeds 200 °C, and residual moisture above 250 ppm accelerates ester hydrolysis, producing a measurable loss of bubble stability, surface haze, and gel accumulation on the die lip. Converters have observed that intermittent bubble flutter in monolayer blown film is most commonly traced to moisture re-absorption during hopper residence or to insufficient regeneration of the desiccant bed. Because PLA melt strength is lower than that of LDPE, a dual-lip air ring and an elevated frost line height are generally required to stabilize the bubble; the frost line is maintained 3 to 5 die diameters above the die. In cast film operations, the molten web is pinned to a chill roll maintained at 20 to 40 °C to reduce crystallization haze and blocking. Back pressure at the die is monitored; if screen-pack differential pressure rises by more than 20% from start-up baseline, gel accumulation from thermal degradation or insufficient filtration is investigated.

Melt temperature is measured by an immersion thermocouple at the die adapter; the target envelope is 170 to 190 °C for blown film and 180 to 200 °C for cast film. When melt temperature exceeds 200 °C, residence time is reduced or screw speed is lowered. In cast film, the die-to-roll gap is set between 10 and 30 mm, and the melt is pinned by electrostatic pinning or vacuum box. Edge trim can be recycled, but trim ratio is kept below 30% to avoid viscosity shifts from repeated thermal history.

Drying Requirements That Precede Stable Melt Processing

Moisture management is a defining constraint for PLA film production. Pellets are dried in a desiccant dryer to a residual moisture level below 250 ppm, typically requiring 4 to 6 h at 70 to 80 °C with a dew point no higher than -40 °C. Drying times longer than 8 h at the upper temperature limit are avoided because pellet surface tack can develop and reduce feed consistency. Hopper residence time is minimized; when ambient relative humidity exceeds 60%, dried pellets are consumed within 30 min or protected by a closed conveying system. Inline moisture analyzers based on near-infrared detection are recommended for continuous verification. Failure to maintain these conditions results in molecular weight reduction, edge tear, bubble instability, and a narrowing of the heat-seal window.

Unlike petrochemical flexible substrates, INZEA F13 brings a renewable carbon signature but imposes a lower melt-strength operating envelope. The product is used in monolayer and laminated structures for industrial composting bags, agricultural films, and retail packaging where compostability certification is specified. Because PLA has lower water vapour barrier than polyolefins, packages intended for high-moisture products require a barrier coating or coextruded structure; water vapour transmission rate measured on a 25 µm film at 38 °C and 90% relative humidity according to ASTM F1249-20 is typically one order of magnitude higher than LDPE. Oxygen transmission rate under ASTM D3985-17 at 23 °C and 0% relative humidity is commonly lower than LDPE but increases sharply with humidity because of the polar character of PLA. Heat-seal initiation temperature for PLA-based flexible film is generally observed between 80 and 110 °C; sealing equipment is operated with dwell times of 0.5 to 1.0 s and jaw pressures sufficient to fuse the interfacial layer without thinning.

Within the INZEA portfolio, the F13 grade is selected specifically for blown and cast film; rigid injection and thermoforming grades are not interchangeable because they exhibit lower melt strength and different crystallization kinetics. Compared with PLA blends designed for heat-resistant applications, the film grade is formulated to retain extensibility and sealability at the expense of thermal resistance; service temperatures above 45–50 °C may cause dimensional distortion under load. This thermal boundary is communicated to end users for warm-fill or hot-climate logistics.

Compared with PBAT or starch-based blown film compounds, PLA-rich film typically exhibits higher modulus and lower elongation at break. The lower moisture barrier is partially offset by higher stiffness and better print surface. Blends with PBAT are sometimes used to improve tear propagation, but such blending modifies compostability certification and must be validated against the selected standard before commercial use.

When INZEA F13 Replaces LDPE in Existing Blown Film Lines

Substitution of INZEA F13 for LDPE requires more than a resin change. Because PLA has a lower critical shear rate and higher shear sensitivity, screw speed is reduced to limit shear heating, and barrel profiles are lowered by approximately 20 to 30 °C relative to LDPE set-points. The die gap is widened to 0.8 mm or more to reduce die pressure and melt fracture. In blown film, a blow-up ratio of 2:1 to 3:1 helps compensate for lower melt strength; bubble cooling is adjusted to raise the frost line and prevent polyethylene-style rapid quench, which can freeze orientation unevenly. The film is stiffer than LDPE and exhibits a distinct rustling noise; lower dart impact resistance is expected under ASTM D1709-16a unless impact modifiers are incorporated. Post-industrial scrap can be reprocessed at levels up to 20% if properly dried, but repeated extrusion passes accelerate molecular weight loss.

Compliance status is application-specific. The following standards are commonly referenced for compostable flexible packaging but do not constitute a certification claim for unverified structures.

Because PLA is an aliphatic polyester, combination with amine-based additives, certain metal stearates, or high-pH fillers can accelerate hydrolysis or cause discoloration. The product is not stored outdoors or in direct sunlight for extended periods; unopened packaging is kept at temperatures below 40 °C and relative humidity below 60%. Shelf life from date of manufacture is typically 12 to 24 months when original packaging is intact, but opened packaging must be dried before use. The material is not suitable for prolonged contact with boiling water or for retort applications. In multilayer film, tie resins with maleic anhydride functionality may produce interfacial instability if the melt temperature exceeds the degradation threshold of the PLA phase. Processors validate adhesive systems on a pilot line before full-scale lamination.