Coextruded blown film lines running TotalEnergies Lumicene Supertouch 40ST05 as the sealant layer on high-speed vertical form-fill-seal packaging for frozen vegetables and dry powder mixes are typically operated with a die gap between 1.8 mm and 2.2 mm and a blow-up ratio between 2.2:1 and 2.8:1. The grade is a metallocene-catalyzed linear low density polyethylene with a nominal density of 0.902 g/cm³ and a melt flow rate of 0.5 g/10 min when tested at 190°C under 2.16 kg load in accordance with ISO 1133-1:2022. The narrow molecular weight distribution and hexene comonomer placement reduce seal initiation temperature compared with Ziegler-Natta LLDPE; seal initiation on 40ST05-based sealant webs typically falls below 105°C at a dwell time of 0.5 s and a sealing pressure of 0.4 N/mm² when measured according to ASTM F88/F88M-21. The Vicat softening point remains below 95°C when measured according to ISO 306, so the extrusion profile must avoid melt temperatures above 240°C to limit oxidative degradation and gel particle formation. Barrel zone setpoints between 180°C and 220°C, with a die temperature of 220°C, are sufficient to maintain stable bubble geometry and prevent melt fracture in a 65 mm blown film die with a 2.0 mm die gap. Addition of a secondary antioxidant at 1,000–2,000 ppm is recommended when converters run recycled edge trim at levels above 15 wt%. The sealant layer is supplied as a food-contact resin under FDA 21 CFR 177.1520(c); finished packaging must satisfy the extraction limits applicable to the specific food type and temperature of use under 21 CFR 176.170(c).

Formulation adjustments for this packaging segment are limited because 40ST05 has inherently low haze and high dart impact. A typical slip package includes erucamide at 500–1,000 ppm and synthetic silica antiblock at 1,000–2,500 ppm; amide migration to the sealant surface reaches equilibrium after 48–72 h at ambient storage. Overdosing erucamide above 1,500 ppm can create seal strength loss because the migrating amide layer acts as a contaminant at the heat-seal interface. On vertical FFS lines producing 2 kg frozen vegetable pillow bags, the seal jaw geometry is normally a knurled flat profile with a temperature differential of 10–15°C between front and rear jaws to compensate for film thickness variation. Hot-tack strength is monitored using ASTM F1921; converters generally require a window of at least 20 N/m at 0.5 s cooling time to prevent product ejection forces from opening the seal. End products include 250 g–5 kg pillow pouches, stand-up pouches with sealant layer thickness of 30–60 µm, and gusseted bags for frozen fruits, potato products, and powdered beverage mixes.

Because the pellet surface of 40ST05 absorbs little moisture, pre-drying is unnecessary below 60% relative humidity; above that threshold, a hopper dryer at 60°C for 2 h eliminates surface splay without altering the heat-seal plateau. In monolayer structures below 60 µm, converters monitor dart drop and tear propagation using ISO 7765-1 Method A and ASTM D1922. Failure modes observed on vertical FFS lines are typically not resin-related but originate from seal jaw misalignment or insufficient cooling air at the forming collar; these defects produce ruptures at the longitudinal seal and are eliminated when the forming tube temperature is held below 40°C.

What Controls Hot-Tack Width in Coextruded Lidding Film Sealant Layers?

In cast film lamination where 40ST05 is used as the sealant layer web laminated to oriented PET, biaxially oriented polypropylene, or aluminium foil, the decisive processing variable is the residual orientation in the cast film after quenching. The film is extruded through a flat die with a die gap of 0.8–1.0 mm onto a chill roll maintained at 15–25°C. Higher chill roll temperatures within this range reduce cooling rate and allow the low-density mLLDPE crystal lamellae to reorganize, which narrows the hot-tack window but lowers seal initiation temperature. Conversely, a chill roll temperature below 15°C produces a quench-induced crystallinity gradient across the film thickness and increases coefficient of friction variability. Lamination converters quantify adhesion with a solventless or solvent-based adhesive at coat weights of 1.5–3.0 g/m²; after lamination, the sealed peel strength is measured according to ASTM F88/F88M-21, with seal bar pressure held at 0.3–0.5 N/mm² and dwell of 0.7–1.0 s. The EU compliance path for this construction is Regulation (EU) No 10/2011 Annex I, with an overall migration limit of 10 mg/dm² for food contact at the tested time and temperature conditions; for fatty food simulants, the specific migration of the adhesive and any printing ink must be evaluated separately.

Coextruded structures replace adhesive lamination where converters run a BOPP/coextruded sealant on high-output pouch lines. The 40ST05 layer is frequently coextruded with a higher density LLDPE skin to improve slip and machinability. In a three-layer cast line using 75 mm and 45 mm extruders with a 1.5 m die, the skin layer thickness is kept between 5 µm and 10 µm, while the 40ST05 core or sealant layer is 20–40 µm. Because 40ST05 exhibits a melting peak at approximately 100°C, the skin layer must not exceed 10 µm if low seal initiation of the combined film is required. The process conflict in this application is between hot-tack width and tear resistance: orienting the cast film in the machine direction increases tensile modulus but reduces the heat-seal plateau. Lidding film for fresh-cut produce and dairy multipack trays typically requires a seal strength of 8–15 N/15 mm and a failure mode of cohesive sealant elongation; specimens tested according to ASTM D882 with 25.4 mm width should show elongation at break above 500% in the machine direction to confirm that the sealant remains ductile. End products include lidding films for rigid PET trays, peelable reclose systems where the sealant interfaces with a pressure-sensitive adhesive pattern, and aluminium foil sachets for desiccants.

Production-scale batch variation in cast lamination is commonly traced to re-extruded edge trim rather than to the 40ST05 lot itself. When edge trim levels reach 20–30%, the melt flow rate of the sealant layer can shift by 0.1–0.2 g/10 min because the recycled material has undergone one additional thermal history. A melt pump is therefore positioned before the flat die to hold die pressure constant and reduce transverse gauge variation. The operating boundary for this application is set by the degradation threshold: melt temperature must not exceed 240°C, and residence time in the die and adapter should remain below 5 min to avoid discolouration and seal strength drift.

Stretch Hood Film Tear Resistance and Pallet Load Stabilization Parameters

Pallet unitization films extruded from 40ST05-rich blown film structures are normally manufactured on three-layer blown film lines with a 70 mm main extruder and an L/D ratio of 30:1. The die gap is set at 2.2–2.5 mm, the blow-up ratio between 3.5:1 and 4.5:1, and the frost line height is raised by 10–15% relative to standard LLDPE to increase machine-direction tear resistance. Stretch hood films require a balance between tensile modulus, elastic recovery after extension, and tear propagation resistance under notched conditions. The contribution of 40ST05 is substantial because the metallocene hexene comonomer distribution reduces tie-chain defects that initiate dart impact failure. In this segment, 40ST05 is blended at 40–70 wt% with an LLDPE or LDPE carrier to achieve a total film gauge of 50–120 µm. The formulation includes a fluoropolymer processing aid at 300–600 ppm to delay melt fracture at high draw rates; additionally, a high molecular weight hindered amine light stabilizer is added at 1,500–3,000 ppm when the film is stored outdoors for more than 6 months.

Mechanical property thresholds are benchmarked using ISO 7765-1 for dart drop, ASTM D5748 for puncture propagation, and ASTM D1922 for Elmendorf tear. For an 80 µm finished stretch hood film, the machine-direction Elmendorf tear value is generally above 5 N and the transverse-direction tear value above 8 N; the MD/TD tear ratio is controlled below 0.7 to prevent splitting during hood application. The tensile stress at 10% elongation, measured according to ISO 527-3, should remain below 6 MPa to permit the double film to open over the pallet corners without excessive force. Seal or weld initiation for stretch hood films is not relevant; instead, the top of the hood is sealed by impulse welding at 160–180°C for 0.8–1.2 s, and the weld seam must exceed 70% of the parent film tensile strength. Process conflicts arise when converters attempt to run 100% 40ST05 at high blow-up ratios; bubble stability deteriorates because the relatively low melt strength of the metallocene grade produces sagging above the frost line. In such cases, the extruder barrel temperature in the rear zone is reduced to 165–180°C and the die gap is narrowed toward 2.0 mm to increase shear heating and stabilize the melt. End products include stretch hoods for palletized concrete block packs, bagged fertilizer stacks, and appliance cartons where load retention force is specified at 10–25 N/100 mm at 20% elongation after 24 h at 23°C.

Field failures in stretch hood films are usually initiated at pallet corners, where the film is stretched over sharp wood or metal edges. To reproduce this condition on the production line, converters use a corner puncture test with a 50 mm rounded probe at 500 mm/min crosshead speed, recording energy to rupture. If energy falls below 5 J, the formulation is adjusted by increasing 40ST05 content by 10 wt% or raising the frost line height; both actions increase transverse tear strength but alter the MD/TD shrinkage balance. The final specification is therefore codified as a minimum machine-direction tear value, a minimum corner rupture energy, and a maximum tensile stress at 10% elongation, rather than by any single dart drop number.

Blending 20–30 wt% of 40ST05 into a LLDPE/C4-C6 resin base for heavy-duty packaging improves puncture resistance without the processing penalty associated with higher molecular weight high-pressure LDPE. The application is not a generic film use; the target is the production of 50–80 µm FFS sacks for construction chemicals, pet food, and salt pellets. The blown film line is typically a mono or three-layer configuration with a 65–90 mm grooved-feed extruder, an L/D ratio of 25:1 to 30:1, and a die gap of 1.8–2.4 mm. In the three-layer structure, 40ST05 is placed in the core layer at 20–40% of total thickness, while the skin layers carry antiblock at 2,000–4,000 ppm to prevent blocking during hot summer storage. The core layer does not contain slip additive. Puncture resistance is evaluated according to ASTM D5748, with a typical failure energy above 10 J for an 80 µm sack film; dart drop impact is tested according to ISO 7765-1 Method A. A lower density of 0.902 g/cm³ contributes chain mobility that absorbs energy under slow puncture and flex-cracking conditions, but it also lowers tensile modulus; therefore, the sack structure must contain a higher density LLDPE layer to maintain creep resistance under 25 kg load.

Extrusion parameters are constrained by the need to avoid excessive oxidation of the metallocene sites. Melt temperature is kept between 210°C and 230°C. The use of a melt pump is strongly recommended because the metallocene resin has lower shear stress at a given screw speed than Ziegler-Natta LLDPE; without a melt pump, output fluctuation can exceed 5% and cause transverse thickness variation in the sack wall. Screen packs are specified with a 20/40/20 mesh sequence upstream of the melt pump, and the breaker plate is fitted with 40% open area to minimize residence time. The final sacks are used for hot-fill of salt up to 50°C, where the low-seal-temperature behavior of 40ST05 permits seal jaw temperature reductions of 10–20°C compared with conventional C4-LLDPE sealant grades, reducing thermal distortion of the film near the seal. The end products include 25 kg FFS sacks for pelletized resins, 15–25 kg pet food bags with side gussets, and block-bottom valve sacks for premixed tile grout. The material must satisfy the relevant packaging waste directive requirements when recycled within the polyolefin stream.

When the sacks are intended for combustible powders or fine-particle chemicals, an antistatic concentrate is added at 2–5 wt%, and surface resistivity is measured according to ASTM D257; the target is below 10^11 Ω/square at 50% relative humidity. This addition slightly reduces dart impact, so the core layer may require an additional 5 wt% 40ST05 to compensate. For export pallets, transport performance is tested according to ISTA 3E; the sack material is only one component of the packaging system, and published data for this specific configuration is limited.

When Cast Film Breathable Backsheet Layers Are Stretched Beyond the Perforation Threshold

In breathable backsheet extrusion for infant care and adult incontinence products, 40ST05 is used at 35–50 wt% as the carrier resin in a calcium carbonate-filled formulation. The cast film is produced on a multi-extruder line with a 90 mm compounding extruder and a slot die gap of 0.6–0.8 mm, then passed through an embossed roller and stretched in the machine direction at draw ratios between 2.0:1 and 3.5:1. The calcium carbonate loading is 50–60 wt% with a mean particle size of 1.4–2.0 µm and a stearic acid surface coating at 0.8–1.2 wt%. The metallocene resin is selected because its narrow comonomer distribution permits uniform filler dispersion at lower specific energy input, reducing filler agglomerates that form pinholes during stretching. Moisture vapour transmission rate is measured according to ASTM E96 at 38°C and 90% relative humidity; for a 35–50 µm breathable film, the WVTR is normally in the 1,500–3,000 g/m²/24 h range, depending on draw ratio and calender roll temperature.

The process conflict in this application is the trade-off between permeability and tensile integrity. Stretching beyond the optimum draw ratio for a given CaCO3 concentration creates microvoid coalescence and lowers hydrostatic head, measured according to AATCC 127 or ISO 811, below 80 mbar. The film must be printed, ultrasonically bonded, or adhesive-laminated to a nonwoven in subsequent converting steps; the bonding window is determined by the melting peak of 40ST05, which is close to 100°C. Ultrasonic bonders running at 20–35 kHz with an amplitude of 25–40 µm produce acceptable bond strength without thermal degradation of the breathable film. Regulatory compliance is confirmed under Regulation (EU) No 10/2011 for plastic materials intended to contact food if the film is used in indirect contact, but for hygiene end products the applicable controls are ISO 10993-5 for cytotoxicity and the manufacturer's restricted substance list for heavy metals, phthalates, and organic tin compounds. End products include breathable backsheets for tape-style and pant-style baby diapers, adult incontinence briefs, and feminine hygiene pads.

Collation shrink films containing 40ST05 in the skin layers are converted into printed sleeves for canned beverages and bottled water multipacks. The film gauge is 45–70 µm, and the shrink orientation is introduced on a biaxial tenter frame at a transverse draw ratio of 5:1 and a machine direction draw ratio of 2:1. The low density and high clarity of 40ST05 maintain total light transmission above 90% when tested according to ASTM D1003; haze remains below 8% after orientation. Shrink force and shrink ratio are measured according to ISO 14616 at 180°C. A 60 µm film typically develops a shrink tension between 2.0 MPa and 4.0 MPa in the transverse direction, which is sufficient to tighten the sleeve around a 6-pack of 330 mL cans without crushing the cans. The material is not used as the primary shrink layer but as a skin layer that improves puncture resistance and reduces tear propagation along the shrink direction. The structure is coextruded with a higher melt strength LLDPE core to resist web sagging and maintain the required shrink temperature window. The printed film is seamed by solvent bonding at 40–60°C; the seam strength must exceed 70% of the transverse tensile strength as measured by ASTM D882. End products include registered-print shrink sleeves for mineral water 6-packs, beverage can 12-packs, and promotional packaging for household chemicals where the label must survive the cold chain without cracking.