Which Coextruded Sealant Layer Formulation Passes High-Speed Vertical Form-Fill-Seal Trials?

Queo VLDPE 0219, a metallocene-catalysed ethylene-octene copolymer with a nominal density of 0.902 g/cm³ per ISO 1183-1:2019, is introduced into the sealant web of five-layer coextruded blown film for high-speed vertical form-fill-seal packaging. The formulation addition ratio in the sealant layer is typically 80–100 wt% Queo VLDPE 0219 and 0–20 wt% of a 0.2–0.5 g/10 min autoclave LDPE; the LDPE fraction is increased when bubble stability on narrow-die, high-BUR lines becomes the limiting factor. The downstream production process on a five-layer line with 55–75 mm screw diameter, 30:1 L/D, and a dual-lip air ring operating at 185–205 °C melt temperature in the VLDPE layer uses a die gap of 2.0–2.4 mm and a blow-up ratio of 2.5–3.0, with internal bubble cooling to prevent heat-seal performance loss from excessive frost-line stress. Sealant layer thickness is maintained at 12–25 μm within a 70–120 μm finished film; below 10 μm, seal initiation becomes unduly sensitive to gauge fluctuation and pinhole formation. Regulatory compliance for food-contact structures is premised on FDA 21 CFR 177.1520 for olefin polymers and Commission Regulation (EU) No 10/2011, where the finished article must not exceed an overall migration of 10 mg/dm² under the assigned food simulant; ethylene in Annex I has no specific migration limit, but the converter must verify the finished laminate against the worst-case simulant selected under Annex III. Seal strength is measured on an MOCON or J&B hot-tack instrument according to ASTM F88/F88M-21 and ASTM F1921-24; production release criteria commonly require a minimum seal strength of 1.5–3.0 N/25 mm across the 85–95 °C jaw temperature window, depending on sealant thickness and dwell time. Terminal product types include frozen vegetable pillow bags, fresh-cut produce flow packs, resealable zip pouches with blown film zipper profiles, and inner liners for coffee powder sachets where low seal initiation and high hot tack are required to prevent product contamination during jaw release.

In cast-stretch-pallet-unitization lines producing 12–25 μm pre-stretched machine film at die widths of 3,500–4,200 mm and line speeds above 600 m/min, the formulation addition ratio for the cling layer is 30–60 wt% Queo VLDPE 0219 relative to total cling-layer polymer. The remaining cling-layer matrix is an octene LLDPE with a melt flow rate of 1.0–2.0 g/10 min, while 1–3 wt% polyisobutylene is metered into the same stream for cling generation and 0.5–1.5 wt% non-migrating silica antiblock is added to control unwind force without eliminating cling. Core layers are formulated without polyisobutylene to maintain monolayer unwind stability and pre-stretch uniformity. The downstream production process uses a cast film line with chill roll temperature set between 15–25 °C, melt temperature 220–245 °C, and powered pre-stretch at the pallet-wrapping machine of 200–300%. Compliance for industrial secondary packaging is controlled under REACH Regulation (EC) No 1907/2006; if direct food contact is claimed, the converter must establish conformity with EU Regulation (EU) No 10/2011 or FDA 21 CFR 177.1520, although PIB-containing cling layers are normally excluded from direct food contact because of additive migration constraints. Puncture resistance is assessed by ASTM D5748-95(2019) and cling by ASTM D5458-95(2020); these are the relevant quality-control methods for a film whose primary mechanical risk is edge tear during turntable pre-stretch cycling. Terminal product types include machine stretch film for pallet unitisation, hand stretch film for low-speed secondary packaging, and pallet hood film where the top edge is heat-sealed rather than cling-lap sealed.

Extrusion Coating and Laminating on Liquid Carton Board

Extrusion coating lines for liquid carton board apply molten Queo VLDPE 0219 as a sealing layer or as a blend partner with autoclave LDPE. The formulation addition ratio in the sealing coating is 80–100 wt% Queo VLDPE 0219 when used as a thin heat-seal layer at 8–15 g/m² coating weight; in thicker laminating webs requiring more melt strength, a blend of 15–30 wt% Queo VLDPE 0219 with autoclave LDPE is used to maintain melt curtain stability at high line speed. The downstream production process on a tandem extrusion coating line with 90–120 mm screw diameter and 28:1–30:1 L/D operates at 285–320 °C melt temperature, a melt curtain length of 150–300 mm, and line speed of 300–600 m/min; ozone treatment of the melt curtain and corona discharge to 42–48 dyn/cm on the substrate are required before lamination to aluminium foil or paperboard to prevent adhesion failure. The processing window is narrow because melt temperatures below 280 °C reduce adhesion to foil, while sustained operation above 320 °C promotes oxidative gel formation in the melt curtain. The narrow molecular weight distribution of metallocene VLDPE reduces neck-in relative to autoclave LDPE at equivalent melt temperature, but converters must verify edge bead control by monitoring melt pressure and die lip temperature uniformity across the 1,200–1,500 mm die width. Regulatory compliance for aseptic liquid carton board is evaluated under FDA 21 CFR 177.1520 for the polymer layer and FDA 21 CFR 176.170 for the paperboard component, with EU compliance under Regulation (EC) No 1935/2004 and EU Regulation (EU) No 10/2011; overall migration in finished articles must not exceed 10 mg/dm². Terminal product types include gable-top cartons, aseptic brick packages for dairy and juice, and laminated sachet webs where the VLDPE outer sealant layer contacts the product.

When Queo VLDPE 0219 is let down into impact-modified polypropylene compounds for injection-moulded cold-chain logistics boxes, the addition ratio is generally evaluated across a 5–20 wt% range; compounds based on PP homopolymer or recycled PP are more likely to use 15–20 wt%, while random copolymer PP compounds with lower intrinsic brittleness are tested at 5–10 wt%. The downstream production process uses a co-rotating twin-screw extruder with 40–50 mm screw diameter and 36:1–40:1 L/D, a barrel temperature profile of 180–220 °C, strand pelletizing or underwater pelletizing, and injection moulding at melt temperatures 200–235 °C with clamp force settings between 1,200–3,500 kN depending on tool size. Published data for this specific 0.902 g/cm³ VLDPE grade in PP impact modification is limited; therefore notched Izod results must be generated on the actual compound according to ISO 180:2023 or ASTM D256-23 at 23 °C and -20 °C, rather than transferred from generic ethylene-octene plastomer literature. Regulatory compliance for food-contact logistics boxes requires the finished PP compound to satisfy EU Regulation (EU) No 10/2011 with an overall migration limit of 10 mg/dm² and, for US export, FDA 21 CFR 177.1520; non-food internal appliance parts are handled under REACH Regulation (EC) No 1907/2006. Terminal product types include cold-chain distribution crates, reusable fish boxes, appliance internal structural components, and automotive interior trim backings.

Heavy-Duty Shipping Sack Liners Demand a Lower Seal Initiation Temperature

In heavy-duty sack liner production, Queo VLDPE 0219 is coextruded as the inner sealant web of woven polypropylene or paper shipping sacks. The formulation addition ratio in the liner film is 60–90 wt% Queo VLDPE 0219 with 10–40 wt% octene LLDPE; the LLDPE fraction is adjusted upward when bubble stability is reduced by high ambient humidity in non-conditioned extrusion halls. The downstream production process uses blown film extrusion for a liner thickness of 30–50 μm, followed by lamination or adhesive bonding to the outer woven fabric, then bottom sealing at 115–135 °C seal bar temperature, 0.5–1.5 s dwell, and 3–5 bar pneumatic pressure; the seal must survive drop tests specified by the applicable transport regulation. Compliance for sacks used with hazardous fillers is established through UN performance tests under ADR/RID/IMDG Code for the relevant packaging type, and material compliance for non-food industrial use is managed under REACH Regulation (EC) No 1907/2006; when the sack is used for food ingredients such as retail-scale pet food or flour, FDA 21 CFR 177.1520 and EU Regulation (EU) No 10/2011 control the liner layer. Terminal product types include 25 kg sacks for synthetic resin powder, carbon black masterbatch, fertilizers, and construction chemicals.