In thermoformed CPLA tray lines, a 25–40 µm printed or unprinted lidding membrane is sealed against a crystalline PLA flange at 95–125 °C. ECOPLAN -FLEX Flexible Heat-Sealable Compostable Polylactic Acid is typically dry-blended with standard semi-crystalline PLA at a ratio from 50:50 to 70:30 before cast film extrusion. The addition of ECOPLAN -FLEX lowers the amorphous-phase seal initiation threshold because the flexible comonomer segments disrupt crystalline packing at the seal interface. Glass transition behaviour measured by ASTM D3418-21 occurs near 55–58 °C for the sealant phase, while the crystalline tray flange retains dimensional stability above 90 °C. On a 30:1 L/D single-screw cast line with a 1.5–2.0 mm die gap, the blend is processed at a melt temperature of 195–215 °C and a chill roll set point of 20–28 °C. Seal strength after a 0.4–0.8 s dwell and 25–40 N/cm² jaw pressure is typically 6–14 N/15 mm when tested to ASTM F88/F88M-21. Peelable opening behaviour is controlled by the ratio of ECOPLAN -FLEX to crystalline PLA and by tray flange cleanliness. A 70:30 ECOPLAN -FLEX-to-PLA blend gives an easier peel seal, while a 50:50 blend shifts failure toward film tear at higher seal strength. Converters measure hot tack on a laboratory sealer at 0.3 s dwell and record acceptable hot tack from 90 °C upward, but published data for this specific tray-flange configuration is limited and line trial qualification remains necessary. Food-contact use requires compliance with EU Regulation 10/2011 overall migration below 10 mg/dm², while industrial composting certification follows EN 13432:2000 for the entire printed lid. This lidding is not suitable for retort or ovenable formats; continuous service above 45 °C may soften the seal area and reduce peel strength before the tray reaches its intended cold-chain temperature. Moisture exposure before sealing should be controlled because PLA-based films above 0.3 wt% moisture content exhibit bubbles and pinholes in the seal interface. Drying in a desiccant dryer at 70–80 °C for 4–6 h to below 200 ppm residual moisture is required for films exposed to ambient relative humidity above 60%.

Where Is a Coextruded Skin of ECOPLAN -FLEX Used in Three-Layer Compostable Barrier Pouch Stock?

When a middle layer of metallised PLA or a biodegradable barrier coating is combined with an ECOPLAN -FLEX sealant skin, the resulting three-layer web can replace conventional polyethylene-EVA pouches for dry snacks, powders, and single-serve items. The sealant skin is extruded at 12–20 µm per side on a total gauge of 50–90 µm, usually representing 20–40 wt% of the entire structure. Coextrusion is performed on a 24:1 L/D to 30:1 L/D three-layer blown film line with a die gap of 1.2–2.0 mm and a blow-up ratio of 2.0–3.0. Because ECOPLAN -FLEX is a PLA-based sealant, tie-layer placement is generally avoided and direct skin adhesion is assessed by the converter through visual peel after slitting. Heat-seal initiation is observed between 80 °C and 110 °C on flat-bed laboratory sealers, but high-speed vertical form-fill-seal jaw temperatures are offset upward by 10–20 °C to compensate for short dwell. Hot tack is evaluated to ASTM F1921-18 at a 0.3 s seal time and 0.2 s cool time. A production-scale VFFS line running 60–80 packs/min with serrated jaws maintains seal integrity above 8 N/15 mm for a 70 µm laminate when the jaw temperature is held inside 100–120 °C. The inclusion of an anti-block masterbatch at 0.5–1.5 wt% prevents roll blocking during warehouse storage at 30 °C and 50% RH. Barrier performance is a design constraint: the ECOPLAN -FLEX skin does not provide high oxygen or moisture barrier, so the middle layer and an optional coating must control transmission rates. A supplier claim that the sealant alone is a barrier layer would fail both documentation review and end-user shelf-life requirements. Compostability certification for the entire laminate follows ISO 14855-1:2012, with non-degradable barrier coatings kept within the certification body’s permitted threshold. Published data for specific metallised PLA configurations in high-speed VFFS is limited; converter sealing trials under actual fill conditions determine the upper line-speed threshold for each pouch format.

On horizontal form-fill-seal flow-wrappers running 60–120 packs/min, a 20–35 µm cast film containing ECOPLAN -FLEX is used for bakery and dry snack over-wrap. The film is corona-treated to 38–44 mN/m on the print side and controlled to a coefficient of friction of 0.25–0.40 kinetic to ISO 8295 using 500–1,000 ppm of a biodegradable-compliant slip additive. ECOPLAN -FLEX is let down at 60–80 wt% with a standard PLA carrier to reduce seal initiation temperature without excessive blocking. The cast film process uses a 25:1 L/D extruder with a 1.0–1.8 mm die gap and a melt temperature of 190–210 °C. Dwell times on flow-wrap sealing jaws are 10–40 ms, which places more load on hot tack than on plateau seal strength. Processors report that straight knurl seal profiles produce a more uniform seam on ECOPLAN -FLEX films than cross-hatch profiles, but published comparative data for this resin grade remains limited. The film is often reverse-printed and then surface-printed with water-based inks validated under EN 13432:2000. A critical processing boundary is blocking after slitting: coils stored above 35 °C or under stacking pressures above 0.5 bar can develop blocking if the slip package is not matched to reel hardness. Pre-drying is required only when edge trim or recycled film is reintroduced above 20 wt% because residual moisture can create gel-like specks in the melt. The finished film is accepted only when seal strength measured on a laboratory heat sealer remains above 5 N/15 mm after 24 h of conditioning at 23 °C and 50% RH. Industrial compostability certification under ASTM D6400-21 supports downstream claims for municipal collection programs, but home compostability is not automatically satisfied.

When ECOPLAN -FLEX Replaces Ethylene-Vinyl Acetate Sealant in Extrusion-Coated Paper Packs

A coating grade of ECOPLAN -FLEX is applied directly to kraft or clay-coated paper at 18–30 g/m² for dry food and non-food paper packaging. The paper substrate is conditioned to 5–8 wt% moisture before coating; lower moisture can generate pinholing and higher moisture can cause blistering at the chill roll. The extruder is a 28:1 L/D single-screw machine with a barrier screw and a coat-hanger die, operating at a melt temperature of 210–230 °C. The paper web is pre-treated with corona at 2–4 kW and passed over a chill roll maintained at 18–25 °C. Nip roll pressure is set between 3–5 bar to drive the melt into the fibrous surface without causing strike-through. Heat sealing is performed paper-side to paper-side after folding, with the ECOPLAN -FLEX layers facing one another. A flat-bed sealing head at 100–130 °C, a dwell of 0.5–1.0 s, and a jaw pressure of 30–60 N/cm² produces a fibre-tear bond at coat weights above 22 g/m². Below 20 g/m², seal strength becomes irregular because the coating cannot completely bridge fibre roughness; a minimum coat weight of 22 g/m² is therefore specified for leak-prone corners. The resulting package is suitable for dry rice, pasta, tea envelopes, and non-food items such as compostable paper-face shopping bags. It is not suitable for high-fat or moist food unless an appropriate functional barrier is incorporated and migration testing under EU Regulation 10/2011 is completed. Industrial compostability is evaluated according to EN 13432:2000 and ISO 16929 for disintegration; the paper fraction contributes composting mass while the PLA coating must biodegrade within the 180-day window. Converters working with high-viscosity PLA coatings note that edge bead formation increases at line speeds above 150 m/min; edge trim is often re-pelletised with virgin ECOPLAN -FLEX at no more than 15 wt% to prevent die lip build-up.

Stand-Up Pouch Sealant Web and Zipper-Compatible Compostable Structures

In stand-up pouch conversion, the ECOPLAN -FLEX sealant web is adhesive-laminated to a compostable barrier film, typically a metallised or coated PLA/PBAT structure, at a dry adhesive coat weight of 1.8–2.5 g/m². The sealant portion is 25–45 wt% of the finished laminate and is positioned as the innermost layer. Bottom gusset seals, side seals, and zipper flange seals are all produced on a multi-station heat sealer. Jaw temperatures are maintained between 105 °C and 135 °C with dwell times of 0.5–1.2 s and pressures of 2–4 bar. Zipper flange sealing is the most variable operation: the additional thickness of the zipper profile creates a thermal lag that reduces interface temperature at equivalent jaw settings. Published data for zipper pinch seals on this specific resin system is limited, so converters qualify zipper fusion by stepwise temperature profiling and ASTM F88/F88M-21 seal strength measurement. In zipper-free areas, seal strength commonly ranges from 15–30 N/15 mm; in zipper flange areas, the lower limit is process-dependent and must not be extrapolated from flat film values. The pouch structure is designed for dry food, powder personal care sachets, and water-free detergent formulations where the filled product is shelf-stable and moisture ingress is not critical. If the pouch requires high gas barrier, the intermediate layer must provide the required oxygen transmission rate because the ECOPLAN -FLEX sealant skin has limited inherent barrier. Side-gusset folding introduces stress concentrations at the gusset corners; ultrasonic inspection of fold gauge is used to reject corners below 60% of nominal wall thickness. A drop test of filled pouches at 1 m on a rigid floor is used as an internal release criterion, but standardised test data for compostable stand-up pouches under this exact configuration is not widely published. Compostability of the complete pouch is certified under EN 13432:2000 or ASTM D6400-21, and the zipper profile must also be included in the certification scope or removed from the compostability claim. The pouch is not suitable for retort, pasteurisation above 65 °C, or liquid products without a membrane-based fitment that isolates the sealant from continuous hydraulic stress.

For compostable tea sachets and infuser packs, a heat-sealed seam is formed between a nonwoven PLA substrate and a thin ECOPLAN -FLEX sealant strip applied at 12–18 g/m². The nonwoven is fed from a high-loft carded web and pre-heated to 45–60 °C before sealing to reduce thermal draw. A rotary sealing drum at 95–115 °C with 0.3–0.6 s dwell and 10–20 N/cm² pressure produces a seam strength of 3–6 N/15 mm on dry nonwoven. This strength range is sufficient for single-use infuser bags but not for compression-loaded coffee pods. The sealant strip must cover the entire seal zone with no gaps exceeding 0.5 mm, because exposed nonwoven fibres do not fuse and create leak paths. The finished sachet is assessed for food contact under EU Regulation 10/2011 and for industrial compostability under EN 13432:2000. A high-humidity brewing environment does not degrade the seam before use, but wet tea leaves remaining in the sachet after disposal initiate biodegradation only under composting temperatures and moisture, not under ambient kitchen storage.

Seal Initiation Shift After 12 Weeks at 60% RH as a Process Boundary

Accelerated shelf-life testing on 45 µm mailer film containing ECOPLAN -FLEX shows that seal initiation can shift upward by 5–8 °C after 12 weeks of storage at 23 °C and 60% RH. This is a process boundary for e-commerce mailer conversion, not a formulation failure, because the flexible PLA phase absorbs moisture and the slip or anti-block package migrates to the surface. The mailer film is produced on a blown film line with a 2.5–3.5 blow-up ratio, a 1.2–1.8 mm die gap, and a melt temperature of 180–205 °C. ECOPLAN -FLEX is blended at 15–30 wt% with a compostable PBAT-rich flexibiliser and standard PLA to achieve the tear-initiation resistance needed for parcel handling. Heat-sealed bottom seams are sealed at 110–130 °C with a dwell of 0.6–1.5 s and a jaw pressure of 3–5 bar. The resulting seam strength is typically 20–40 N/15 mm in the machine direction, but cross-seam film orientation reduces transverse seal strength by 10–20%. Converters must set the bottom seal jaw according to transverse-direction data and not machine-direction data. The mailer is often perforated near the top or fitted with a tear tape; ECOPLAN -FLEX has limited tear anisotropy compared with highly oriented PET, so tear propagation must be verified on filled bags. Load limits are normally specified at 2–3 kg for a 50 µm mailer because higher mass causes creep at the heat-sealed seam during handling. Compostability of the final mailer is assessed under EN 13432:2000 for industrial systems; the presence of pressure-sensitive labels, tear tape, and inks must be included in the certification scope. Cold-chain performance remains constrained: film flexibility decreases below 5 °C and the heat-sealed seams should not be flexed while frozen because PLA-rich zones may initiate cracks. This defines the lower practical use boundary for flexible compostable mailers in unheated logistics chains.