ecovio FS2312 Blown Film Compostable PLA Compound is a pelletized biodegradable polymer blend formulated for tubular blown-film extrusion. The material combines a poly(lactic acid) fraction with an aliphatic-aromatic copolyester to maintain melt strength during bubble expansion while generating film stiffness characteristic of PLA. Manufacturer-published property envelopes place density at 1.25–1.28 g/cm³ under ISO 1183-1:2019 and melt volume flow rate at 3.0–5.0 cm³/10 min at 190 °C / 2.16 kg under ISO 1133-1:2022. The target film thickness range spans 10–80 µm, with commercial use concentrated in organic waste bags, carrier bags, produce packaging, and agricultural mulch. The grade is differentiated from neat PLA film by improved bubble stability and from lower-renewable PBAT-rich compostable films by a higher modulus and lower elongation at break.

Melt rheology measured on a L/D 30 single-screw blown-film extruder with a 45 mm diameter barrier screw shows stable bubble formation only after the resin is dried below 0.04 % moisture. A desiccant dryer set to 70 °C for 3–4 h with a dew point of -40 °C or lower is required when ambient relative humidity exceeds 60 %. Residual moisture above that threshold reduces melt viscosity, generates surface roughness, and can produce bubble tears directly above the frost line. The recommended barrel temperature profile from feed to die is 160/170/175/175/170 °C; melt temperatures above 200 °C accelerate lactide depolymerization, resulting in die-lip deposits and a progressive loss of bubble pressure stability.

On a 45 mm extruder equipped with a screen pack filter, steady-state melt pressure is usually 180–220 bar with a die pressure of 70–90 bar; excursions above 240 bar often correlate with partial gel build-up and should be managed by reducing screw speed or purging with polyethylene. Because the PLA phase in FS2312 solidifies more rapidly than LDPE under the same air flow, the air ring lip angle and frost line height must be adjusted relative to conventional polyethylene conditions. A blow-up ratio of 2.5–3.5 and a frost line height of 3–6 die diameters are typical starting values for monolayer structures.

What limits melt temperature during bubble expansion?

The upper melt-temperature boundary is governed by poly(lactic acid) chain scission rather than by copolyester degradation. Differential scanning calorimetry under ISO 11357-3:2018 typically records a PLA melting endotherm between 155 °C and 165 °C and a cold-crystallization exotherm between 95 °C and 110 °C. At die melt temperatures above 195–200 °C, terminal melt strength falls steeply. On a 65 mm three-layer line, bubble instabilities and dart-impact reductions above 30 % of the lower-temperature baseline have been observed within 20 min of exceeding 205 °C. The lower boundary is set by incomplete melting and die line formation. A die temperature below 150 °C causes increased die swelling and visible flow lines in 20 µm film. The practical operating window is therefore 165–190 °C at the die.

Die gap is typically held at 0.8–1.4 mm for monolayer FS2312 film. A gap below 0.8 mm increases shear heating and can push melt temperature above 200 °C even when barrel set points are unchanged. A gap above 1.4 mm lowers shear and may require a higher melt temperature to obtain gauge uniformity, which narrows the already limited temperature window. For coextruded A/B/A structures, skin and core melt temperatures should remain within 5 °C of each other to avoid interfacial flow instability and micro-layer breakup.

Because FS2312 is a PLA-bearing blend, additive masterbatches must be selected for neutral or slightly acidic pH. Amine-based slip or antiblock concentrates are avoided because aminolysis can accelerate PLA molar mass loss at processing temperatures. Erucamide slip is normally added at 0.05–0.15 wt% to avoid reducing heat-seal strength. Titanium dioxide white masterbatch based on the same copolyester carrier is used at 4–8 % for opacity; silicate antiblock can be used at 0.5–2.0 phr, but above 2.0 phr reduces dart impact in thin-gauge film by increasing flaw density.

Organic waste bags made from 25–30 µm FS2312 film are evaluated under EN 13592 load-carrying tests for household refuse sacks and under ISO 527-3:2018 for tensile behavior after 48 h conditioning at 23 °C and 50 % relative humidity. Typical film tensile strength ranges from 35–50 MPa in machine direction and 25–35 MPa in transverse direction, while elongation at break is generally 150–350 % machine direction and 250–400 % transverse direction. Puncture resistance per DIN 14477 is sufficient for municipal organic waste capture when local collection cycles do not exceed 7 days under humid loading. Carrier bags are tested for heat-seal strength per ASTM F88/F88M-21; sealing generally occurs at 100–130 °C with a dwell of 0.3–0.5 s and sealing pressure of 1.0–1.5 N/mm².

Agricultural mulch films of 12–25 µm thickness require a UV-stabilizer masterbatch. Unstabilized FS2312 film loses tensile impact resistance after outdoor exposure because the PLA fraction is subject to photolytic chain scission. Published data for this specific configuration is limited, so outdoor residence time must be confirmed by field tests under ISO 17556:2019 soil-biodegradation conditions rather than extrapolated from industrial compostability certification.

Interchangeability with neat PLA and PBAT-rich film grades

FS2312 is not a direct substitute for neat PLA blown film. Neat PLA exhibits a narrow bubble window, typically requiring a blow-up ratio below 2.0 and a die gap above 1.2 mm because its elongation viscosity and melt strength are lower. FS2312 retains a higher modulus than PBAT-rich ecovio blown-film grades because the dispersed PLA phase contributes rigidity; the trade-off appears as a lower tear-propagation resistance under ISO 6383-2:1983. In comparative trials, PBAT-rich grades show Elmendorf tear values roughly 1.5–2.0 times higher than FS2312 at equivalent 30 µm thickness, while FS2312 exhibits tensile modulus values 1.3–1.8 times higher. Compared with starch-filled biodegradable compounds, FS2312 has lower equilibrium moisture uptake and less viscosity drift after 4 h at 23 °C and 50 % relative humidity; starch compounds commonly require closed feed systems and vented extruders to manage water release during processing.

Relative to LDPE, FS2312 is not a drop-in replacement. Vicat softening temperature under ISO 306:2022 method A120 is about 70–80 °C, which restricts use in hot-fill or high-temperature logistics. The film softens and deforms under belt-seal temperatures above 130 °C; thus FS2312 is incompatible with conventional LDPE high-speed hot-bar sealing lines optimized for 150–180 °C. Converters must lower sealing temperature or use impulse sealing with controlled dwell. Unwinding tension should be kept below 8–10 N/m web width to avoid film elongation and blocking on the roll above 40 °C storage.

Conditioning to 50 % relative humidity is required before mechanical testing because PLA mechanical response is moisture-sensitive. Below 20 % RH, film becomes stiffer and more brittle; above 80 % RH, it loses modulus and gains impact softness. Seal-strength tests without 24 h conditioning per ASTM D4332-22 may understate equilibrium seal performance.

When film thickness exceeds 50 µm, disintegration lag becomes certification-critical

Industrial compostability certification does not imply home compostability at ambient soil temperatures. For FS2312, home compost certification is not automatic; converters must verify the specific certificate for the final film structure because thickness, pigments, and adhesive labels can alter disintegration kinetics. Disintegration lag above 50 µm film thickness is certification-critical under EN 13432:2000/Amd 2:2021, and published data for this specific configuration is limited.

Biodegradation is measured under ISO 14855-1:2012 at 58 °C, and certification requires at least 90 % mineralization relative to a positive reference within 180 days. Disintegration is assessed under ISO 16929:2021; after 12 weeks in mature compost, no more than 10 % of the original dry mass may remain on a 2 mm sieve. Ecotoxicity is evaluated by plant growth tests according to OECD 208 or the corresponding annex of EN 13432.

FS2312 is not designed for anaerobic digesters; in high-solids anaerobic digestion at mesophilic temperatures, degradation may produce methane but is not a certified disposal pathway. Converters must not label FS2312 packaging as home compostable unless the exact final structure is certified by a recognized body. Biobased carbon content measured by ASTM D6866-22 is usually 55–65 %, making the grade suitable for applications requiring renewable carbon but not for applications with a 90 % biobased threshold.

In production-scale blown-film runs on a 65 mm single-screw extruder with L/D 30 and a 250 mm spiral mandrel die, the following failure modes are observed: bubble flutter when frost line height is increased above 6 die diameters; die-lip lactide deposits when melt temperature is maintained above 200 °C for more than 30 min; and gauge bands when the air ring lip angle is not reduced relative to LDPE because FS2312 solidifies more rapidly than LDPE under the same air flow. Regrind addition is limited to 20–30 % in monolayer structures; higher regrind fractions reduce dart impact and heat-seal strength because the third-pass PLA molar mass has undergone additional chain scission.