In aseptic liquid packaging board converting, Borealis LDPE NAV101M is used as an extrusion-coated sealing layer that must function under high-speed filling, sealing, and sterilisation conditions without film rupture or delamination from the paperboard substrate. The material is assessed under Commission Regulation (EU) No 10/2011 and its amendments for plastic food-contact materials, with an overall migration limit of 10 mg/dm² determined using food simulants appropriate to the filled product, typically simulant A, B, or C for aqueous, acidic, and low-alcohol liquids; for fatty products the converter verifies compliance under the specific migration testing regime for olefinic matrices. United States food-contact status is established through 21 CFR § 177.1520(c) for olefin polymers, while incoming melt-flow consistency is verified by ISO 1133-1:2022 at 190 °C with a 2.16 kg load and density is controlled by ISO 1183-1:2019 or ASTM D1505-18. In a mono-layer board coating structure the formulation addition ratio is 100 wt% NAV101M; in coextruded structures the product-contact sealing layer is commonly 85–90 wt% NAV101M with 10–15 wt% clean internally generated edge trim regrind that has been ground, dried, and re-introduced through a vented single-screw feed section. Downstream production is carried out on tandem or single-station extrusion coating lines with a screw L/D ratio of 24:1 to 30:1, a flat die with internal deckle adjustment, barrel temperature zones increasing from 180 °C at the feed throat to 290–320 °C at the adapter, an air gap of 150–250 mm, and a polished chill roll maintained at 15–25 °C. Coating weight is normally 12–30 g/m², increasing to 35–50 g/m² only where extra seal robustness or barrier contribution is required; in-line optical pinhole detection at web speeds of 300–500 m/min is used to reject fibre tear and insufficient polymer coverage. Terminal product types include aseptic brick cartons for UHT milk, juice, cream, liquid egg, and broth, as well as gable-top paperboard cartons and small portion packs.

Why Is NAV101M Blended at 12–20 wt% Into LLDPE Blown Film Formulations?

When linear-low-density polyethylene film producers add 12–20 wt% of a high-pressure LDPE such as NAV101M to a C4, C6, or C8 LLDPE base resin, the primary modification is rheological rather than merely dilutional. At this addition level, die pressure and apparent shear viscosity are reduced, bubble stability improves, and melt fracture is suppressed because the long-chain-branched LDPE contributes elongational strain hardening to the blown film bubble; below 12 wt% the bubble-stabilising effect is often insufficient on high-stalk and high-neck configurations, while above 20 wt% dart impact and Elmendorf tear can decline to levels that are unacceptable for demanding film structures. Compliance is anchored to ISO 527-3:2018 for tensile properties, ASTM D882-18 for thin film tensile, ASTM D1709-22 for falling dart impact, ASTM D1922-15 for Elmendorf tear, and ASTM D1003-21 for luminous transmittance and haze. Downstream production is typically three-layer coextrusion blown film with a die gap of 1.8–2.4 mm, blow-up ratio of 2.2:1 to 3.0:1, frost-line height of 0.8–1.5 m, and melt temperature of 185–205 °C; barrel temperature zones are set between 170 °C and 205 °C depending on the position of the barrier screw mixing section and the output required from the extrusion line. Terminal product types include heavy-duty sacks, collation shrink film, frozen food film, industrial liners, and agricultural silage film where a balance of bubble stability, optical clarity, and seal performance is required.

When Aluminium Foil Lamination Requires a Low Seal Initiation Temperature

For flexible packaging structures that combine 7–12 µm aluminium foil with printed PET or BOPP, the NAV101M layer is extrusion-laminated at 18–30 g/m² as the heat-seal layer facing the packaged product. In a standard foil lamination structure the addition ratio is 100 wt% NAV101M for the sealant layer, while tie layers use maleic anhydride-modified polyethylene or ethylene-acrylic acid copolymer at 8–15 g/m²; if a blended sealant is designed for elevated hot-tack strength, up to 15 wt% LLDPE may be introduced, with the understanding that seal initiation temperature may increase relative to a pure LDPE sealant. Compliance for food-contact flexible packaging is governed by EU Regulation (EU) No 10/2011 with its overall migration limit of 10 mg/dm², supplemented by 21 CFR § 177.1520 for olefin polymer food-contact use; seal initiation is characterised by ASTM F1921-12(2018) and seal strength by ASTM F88/F88M-21. The LDPE sealant layer typically exhibits a seal initiation temperature between 95 °C and 110 °C, though the exact value must be confirmed on the specific lamination line because sealing is influenced by foil gauge, nip pressure, and thermal history. The production process employs an extrusion lamination line with a flat die, melt temperature of 290–320 °C, air gap of 180–250 mm, nip pressure of 30–60 N/mm, and corona pre-treatment of the foil to 40–44 mN/m to reduce adhesion failure at the foil-polymer interface. Terminal products include dry beverage sachets, seasoning sachets, instant soup pouches, cosmetic single-use sachets, and tea bag envelopes where seal integrity through gusset folds is a critical acceptance criterion.

On high-speed paper cup forming lines, extrusion-coated cupstock is scored, folded, side-seam sealed, and bottom-curled at rates exceeding 180 cups/min, so the LDPE coating must tolerate rapid thermal sealing without tearing, pinholing, or delaminating from the paperboard under mechanical stress. In this application the internal layer is extruded at 18–25 g/m² and the external layer at 12–20 g/m²; the internal clear layer is typically 100 wt% NAV101M, while the external layer may be 85–92 wt% NAV101M with 8–15 wt% white or coloured masterbatch added at the coating extruder feed port. The relevant food-contact framework is EU Regulation (EC) No 1935/2004 supported by EU Regulation (EU) No 10/2011, with overall migration below 10 mg/dm² demonstrated in simulant B for aqueous drinks and in 3 % acetic acid for acidic beverages. Downstream production uses a tandem or single-station extrusion coating line with dry edge trim removal, melt temperature of 285–310 °C, chill roll temperature of 10–20 °C, in-line pinhole detection at web speeds of 250–350 m/min, and corona treatment of the printed side to 40–44 mN/m where water-based flexographic inks are subsequently applied. Terminal products include hot and cold beverage paper cups, soup cups, ice cream cups, and food service containers with side seams exposed to hot liquid for up to 120 min under end-user test protocols.

Woven Polypropylene Sack Coating and Moisture Vapour Barrier

For laminated woven polypropylene sacks used in bulk commodity packaging, NAV101M is applied as an extrusion coating or lamination layer that seals the open weave surface and reduces moisture vapour transmission and dust leakage. The addition ratio in an unmodified coating is 100 wt% NAV101M at a coating weight of 20–35 g/m²; where a white or printed finish is specified, a pigment masterbatch is dosed at 8–15 wt% into the feedstream, producing a final pigment concentration of 4–8 wt% in the finished coating. Compliance is established by ISO 15106-1:2018 for water vapour transmission rate at 38 °C and 90 % RH, ASTM D1876-08 for peel adhesion of the coating to the woven fabric, and ASTM D1709-22 or ISO 7765-1:2004 for impact resistance of the coated laminate. The production process employs a wide-web extrusion coating or lamination line with a melt temperature of 280–320 °C, an air gap of 150–250 mm, and an in-line corona treater set to 42–46 mN/m; the woven fabric enters the nip at a controlled tension of 80–150 N/m to prevent baggy edges and transverse wrinkling, and the laminated web is chilled on a matte or polished roll at 15–25 °C before edge trimming and rewinding. Terminal product types include woven sacks for petrochemical resin pellets, fertiliser, rice, animal feed, salt, and cement with valve or open-mouth closures, where the coating must survive filling drop cycles and palletised warehouse storage at elevated humidity.

Masterbatch Carrier Resin on Co-Rotating Twin-Screw Co-Kneaders

Colour and additive masterbatch producers select NAV101M as a carrier phase when a heat-stable, food-contact-clear LDPE is required for let-down into LDPE or LLDPE films, coatings, and blow-moulded articles. In a pigment masterbatch the carrier addition ratio is 35–55 wt% NAV101M, with 40–60 wt% inorganic or organic pigment, 5–10 wt% dispersant wax, and up to 1 wt% processing stabiliser; in an additive masterbatch for slip, antistatic, or UV stabilisation, the active additive is loaded at 10–25 wt% with the balance NAV101M. Downstream converters let this masterbatch down at 2–4 wt% into natural LDPE or LLDPE, yielding final additive concentrations of 0.2–1 wt% in thin film and extrusion coating applications. Compliance for packaging-grade masterbatch is assessed under EU Regulation (EU) No 10/2011 for the final article with total overall migration below 10 mg/dm², and under 21 CFR § 177.1520 for olefin polymer carriers; where the masterbatch is supplied into electrical or electronic applications, RoHS Directive 2011/65/EU restricts lead, cadmium, mercury, hexavalent chromium, PBB, and PBDE in the final homogeneous material. The production process is a co-rotating twin-screw extruder with an L/D ratio of 36:1 to 48:1, modular screw elements including kneading blocks, side feeding for heat-sensitive or high-volume pigments, screw speed of 300–900 rpm, specific mechanical energy input of 0.15–0.35 kWh/kg, melt temperature of 160–200 °C, and underwater or strand pelletising. Terminal products include colour masterbatches, white masterbatches, antioxidant masterbatches, slip masterbatches, and UV stabiliser masterbatches used in flexible packaging, rigid containers, closures, and extrusion coatings.