The application footprint of SABIC COHERE VLDPE 8402 is defined by a nominal density of 902 kg/m³ (ISO 1183-1:2019) and a melt flow rate of 2.0 g/10 min (ISO 1133-1:2022, 190 °C/2.16 kg). The resin is deployed where metallocene-catalyzed short-chain branching translates into low seal initiation, high hot-tack, or low modulus. The downstream segments below are restricted to film and surface-protection structures in which these properties are process-critical, not as a general-purpose polyethylene replacement.

Why Does Seal Initiation Temperature Govern Coextruded Sealant Web Selection?

Flexible food packaging lines running vertical form-fill-seal equipment at speeds above 60 packs/min expose the sealant layer to dwell times below 45 ms. In this regime, the converter cannot rely on elevated seal-bar temperature alone because the outer PET or BOPP print web may shrink or distort. COHERE 8402 is introduced into the sealant layer at 70–100 wt%, with the remainder being a Ziegler-Natta or metallocene LLDPE of density 0.918–0.925 g/cm³ for bending stiffness. If the film requires release from polished seal jaws, a synthetic silica antiblock masterbatch at 0.1–0.3 wt% of a 5 wt% concentrate is used; erucamide slip is excluded from the sealant layer unless the converter validates hot-tack retention and seal strength per ASTM F1921-20 and ASTM F88/F88M-23. The layer is produced on a three-layer blown film line with screw L/D ratio not less than 30:1, die gap 1.8–2.4 mm, blow-up ratio 2.0–2.8, frost line height between 8 and 12 die diameters, and melt temperature 180–220 °C. At die gaps below 1.6 mm, the metallocene narrow molecular weight distribution raises extrusion pressure and melt fracture risk; at die gaps above 2.6 mm, frozen-in orientation is reduced and dart impact declines. For food contact, the finished structure must comply with EU Regulation (EC) No 1935/2004, EU Regulation (EU) No 10/2011 overall migration limit of 10 mg/dm², and FDA 21 CFR 177.1520(c) for olefin polymers under the intended conditions of use. Terminal products include stand-up pouches, lidding webs, and stick packs.

During heavy-duty form-fill-seal sack manufacturing for polymer granulate and granular chemical distribution, slow puncture propagation is the limiting failure mode when filled sacks are dropped from 1.2 m height onto pallet edges or warehouse concrete. The sack structure incorporates COHERE 8402 in the core and outer layers at 60–80 wt%, with 20–40 wt% of a 0.918–0.922 g/cm³ LLDPE to raise secant modulus; the inner layer may contain a lower-toughness LDPE only if closure strength is not compromised. Processing uses a triple-layer blown film line with internal bubble cooling, die gap 2.2–2.8 mm, blow-up ratio 1.8–2.4, melt temperature 190–220 °C, and gusseting prior to winder tension control. Dart impact acceptance is thickness-dependent and is determined according to ISO 7765-1; values must be established on the converter’s film structure rather than transferred from monolayer data. The collapsed tube is surface-treated to 38–42 dyn/cm and converted on form-fill-seal stations with sealing bar temperature 150–170 °C and cooling time above 0.5 s. For non-food industrial packaging, REACH (EC) No 1907/2006 and EU Packaging Directive 94/62/EC apply; dangerous goods sacks require additional qualification under the applicable UN Model Regulations packing instruction. Terminal products are 25-kg sacks for polymer resins, catalysts, and granular intermediates.

When Low Modulus and Surface Conformability Control Protective Film Performance

Because temporary protection of pre-coated architectural aluminum, polycarbonate sheet, and stainless steel appliance panels requires surface conformability without stress whitening or edge lift, COHERE 8402 is processed as the core layer at 80–100 wt%; the skin layers may contain 10–20 wt% LLDPE to adjust unwind noise and blocking. When an adhesive is used, a coextruded low-tack pressure-sensitive layer is applied, and the adhesion level is set by peel testing on the target substrate per ASTM D3330/D3330M-22 rather than by assumed tape performance. A cast film line with die gap 0.8–1.2 mm, chill roll temperature 15–25 °C, and melt temperature 190–230 °C is preferred because it limits differential shrinkage that causes film curls. Blocking and coefficient of friction are measured per ASTM D3354 and ASTM D1894 to avoid unwind chatter on high-speed laminating lines. Compliance for electronic appliance flows includes REACH (EC) No 1907/2006 and, where applicable, RoHS Directive 2011/65/EU; films intended for food contact in kitchen appliance protection must separately satisfy EU Regulation (EU) No 10/2011. Published data for high-tack pressure-sensitive adhesive transfer onto COHERE 8402 carrier film is limited, so converter trials on the specific substrate are required before line qualification. Terminal products include protective films for metal coil, sheet, and molded exterior components.

At storage temperatures below −20 °C, seal failure in individually quick-frozen packaging often originates from the brittle fracture of conventional LLDPE sealant layers during case packing and consumer handling. In this application, COHERE 8402 is formulated at 85–100 wt% in the sealant web, with 0–15 wt% LLDPE for stiffness adjustment, and the film thickness is held between 25 µm and 60 µm to balance oxygen barrier and puncture resistance. Blown film lines running this structure use die gap 1.8–2.3 mm, blow-up ratio 2.5–3.0, melt temperature 180–210 °C, and a collapsing frame geometry that minimizes wrinkles before heat sealing. Compliance requires EU Regulation (EU) No 10/2011 overall migration below 10 mg/dm² and FDA 21 CFR 177.1520(c) for olefin polymers; if the structure includes EVOH or nylon, the converter must verify that the sealant layer remains the food contact layer and that migration from tie layers is controlled. Terminal products include frozen vegetable pouches, seafood packs, and frozen meat overwrap.

Stretch Hood Film Tear Propagation and Load Retention

Pallet containment of bagged goods or appliance loads imposes vertical stretch ratios of 60–100% and horizontal stretch of 5–15% without zipper tear propagation along the hood edge. COHERE 8402 is blended with 10–30 wt% of hexene- or octene-LLDPE of density 0.916–0.920 g/cm³ to adjust force retention after stretch; film thickness ranges from 30 µm to 80 µm depending on load mass and corner sharpness. Cast film extrusion with a vacuum box and high-speed winder controls gauge variation to below ±5%; die gap is 1.2–1.8 mm, melt temperature is 200–230 °C, and the primary chill roll is maintained at 20–30 °C. Performance is characterized according to ISO 527-3:2018 for tensile behavior and ISO 7765-2 for instrumented puncture resistance. Non-food service does not require EU Regulation (EU) No 10/2011, but REACH (EC) No 1907/2006 applies to the compound and finished article. Terminal products are pallet hood films for logistics, warehousing, and machinery export crating.