In direct food-contact blown film conversion, SABIC LLDPE 220NT is specified when the converter requires a nominal melt flow rate of 2.0 g/10 min at 190°C under 2.16 kg load according to ISO 1133-1:2022 and a density of 0.922 g/cm³ according to ISO 1183-1:2019. The regulatory file is built around FDA 21 CFR 177.1520(a)(3)(i) for olefin polymers intended for food contact and Commission Regulation (EU) No 10/2011 as amended, with overall migration tested according to EN 1186-1:2002 on the finished film at the intended thickness and food-simulant exposure. The blend formulation on a monolayer blown line commonly uses 60–80 wt% LLDPE 220NT with 20–40 wt% tubular LDPE having a melt index in the 0.25–0.7 g/10 min range to stabilize the bubble and increase melt strength, while slip masterbatch is introduced at 1–3 wt% and antiblock masterbatch at 1–2 wt% depending on film gauge and storage humidity. A fluoropolymer process aid is added at 200–500 ppm to manage die lip build-up during extended runs. Film thicknesses for bread bags are typically 18–30 µm, while frozen food bags and produce roll bags fall in the 40–65 µm range because low-temperature dart impact and tear propagation are the controlling mechanical responses, evaluated per ASTM D1709-16a and ISO 6383-2:1983 respectively. The blown film process uses a die lip gap of 2.0–2.5 mm, a blow-up ratio between 2.2:1 and 3.0:1, melt temperatures of 185–210°C, and a frost-line height of 5–8 die diameters. External condensation from silo storage at relative humidity above 60% is managed by predrying at 60–70°C for 2–4 h; otherwise surface moisture appears as bubble instability and film surface defects. Terminal packaging formats converted from this film include bread bags, frozen food bags, produce roll bags, and pillow pouches for dry food products where seal integrity is verified according to ASTM F88/F88M-23 on continuous heat-seal equipment.

On coextruded three-layer lines, the processor sets the skin layers to control seal initiation and coefficient of friction independently of the core. The 220NT core is held at 50–70 wt% of total film thickness, with the skins each at 15–25 wt%; when lower seal initiation is required, the sealant skin is blended with metallocene LLDPE at 10–30 wt% of that skin layer. Hot-tack behavior is measured according to ASTM F1921-12(2017) because vertical form-fill-seal lines require a sufficiently broad sealing plateau before the fill load is introduced. The coefficient of friction is verified per ISO 8295:1995 on both treated and untreated film surfaces, with target values set between 0.15 and 0.30 depending on packaging machine configuration. The following matrix is applied to direct food-contact film documentation before shipment.

What Alters Tear Propagation in Heavy-Duty Sack Blends?

Because tear propagation and dart drop impact control sack failure during filling, palletizing, and drop tests, heavy-duty open-mouth sacks and FIBC inner liners extruded from LLDPE 220NT are tested using ISO 527-3:2018 for tensile properties, ISO 6383-2:1983 for trouser tear resistance, and ISO 7765-1:1988 or ASTM D1709-16a for dart drop impact. The compound formulation consists of 70–85 wt% LLDPE 220NT, 10–25 wt% post-industrial recycled LLDPE from edge trim and scrap, 2–4 wt% carbon black masterbatch for UV shielding and opacity, and 0.5–1.0 wt% process aid, with recycled content above 25 wt% typically causing measurable gel formation and dart drop variability that is verified per ASTM D1709-16a before the sack lot is released. The extrusion process is configured as a high-stalk bubble with internal bubble cooling, dual-lip air ring, and a die head pressure in the 220–300 bar range; die diameter is generally 250–400 mm, die gap 2.2–3.0 mm, blow-up ratio 2.5:1–3.5:1, and frost-line height 800–1500 mm to orient the film and balance machine-direction and transverse-direction tear. Terminal packaging formats include FIBC inner liners at 80–120 µm, heavy-duty sacks at 120–200 µm, and construction membranes at 150–250 µm where the film is used as temporary protection or vapor control. For sacks used in export transport, closure strength is evaluated using a drop test sequence derived from ISO 7965-2:1993, with fill mass and drop height fixed according to the applicable UN packaging certification where dangerous goods transport is involved. Where closed-loop edge trim is fed back into the outer layer, the melt pressure is monitored continuously because particle contamination from recycled trim above 25 wt% alters bubble stability and can produce thickness bands measurable by a capacitance gauge with deviation exceeding ±8% at the frost line.

For laminating converters producing stand-up pouches and lidding films, sealant webs from SABIC LLDPE 220NT are typically converted on a three-layer blown film line at 25–50 µm and then adhesive-laminated to biaxially oriented polypropylene, polyethylene terephthalate, or polyamide carrier plies. The 220NT sealant layer is used at 100 wt% or blended with metallocene LLDPE at 10–30 wt% to reduce seal initiation temperature and broaden the hot-tack window, with seal strength measured according to ASTM F88/F88M-23 and hot-tack according to ASTM F1921-12(2017). Slip masterbatch is added at 1–2 wt% and antiblock at 0.5–1.5 wt% to maintain package handling on vertical form-fill-seal lines, while the coefficient of friction is verified per ISO 8295:1995 at 0.15–0.30. The blown film process uses a die gap of 1.8–2.2 mm, a blow-up ratio of 2.0:1–2.8:1, and melt temperatures of 185–205°C, followed by corona surface treatment to 40–44 mN/m immediately before lamination. Lamination is performed with solventless polyurethane adhesive at a coating weight of 1.5–2.5 g/m² and nip temperature of 50–60°C. The resultant flexible packaging structures are used in stand-up pouches, lidding films, flow-wrap packaging, and vacuum skin pack webs, where the sealant ply must comply with FDA 21 CFR 177.1520 and EU 10/2011; the adhesive layer is separately assessed under FDA 21 CFR 177.1395 or relevant national adhesives legislation. Direct extrusion coating lines are not the appropriate conversion route for this grade because its 2.0 g/10 min melt index is below the typical melt index range of 7–14 g/10 min required for stable continuous coating at high line speeds; published data for this specific configuration is limited, and converter trials should first quantify neck-in and adhesion on the target substrate before line acceptance.

When LLDPE 220NT Is Formulated with EVA and HALS for Greenhouse Covering

Greenhouse covering and low-tunnel film based on LLDPE 220NT are manufactured on three-layer blown film lines with die diameter between 300 mm and 500 mm and layer ratios of 30/40/30 to separate UV-stabilized outer skins from an inner core. The compound formulation allocates 55–70 wt% LLDPE 220NT as the toughness component, 10–20 wt% ethylene vinyl acetate copolymer with vinyl acetate content of 18–28 wt% for low-temperature flexibility and light transmission, 10–15 wt% LDPE for melt strength, 3–8 wt% hindered amine light stabilizer masterbatch for UV protection, and 1–2 wt% anti-drip additive concentrate. The extrusion process uses a die gap of 2.0–3.0 mm, a blow-up ratio of 2.5:1–3.5:1, melt temperatures between 190°C and 210°C, and a high frost-line setting to promote the surface migration of anti-drip agents. Durability testing follows EN 13206:2017 for thermoplastic covering films for agriculture and horticulture, with accelerated weathering conducted under ISO 4892-3:2016 using QUV-B 313 nm lamps; tensile retention after exposure is measured per ISO 527-3:2018. Terminal product types include single-season greenhouse films at 100–150 µm, low tunnel films at 50–80 µm, and black/white mulch films at 25–35 µm where the 220NT contributes puncture resistance during laying and after stone contact. The service-life classification is matched to the antioxidant and HALS package; films stabilized only for 1–2 seasons are not accepted for multi-season Mediterranean installations without additional UV additive and periodic tensile testing. Anti-drip surface migration is assessed by contact-angle measurement on conditioned film, with acceptance values typically below 30° after 72 h storage at 40°C; failure to reach the specified wetting angle indicates insufficient migration time or inadequate anti-drip concentrate dispersion in the skin layer.

When retail bag converters run high-stalk blown film lines at die diameters below 300 mm, SABIC LLDPE 220NT is introduced as the primary toughness component in blends containing 60–70 wt% 220NT, 20–30 wt% recycled LLDPE from post-industrial sources, 10–20 wt% LDPE for improved bubble stability, and 2–6 wt% calcium carbonate filler masterbatch to control stiffness and cost. The film is extruded at melt temperatures of 180–200°C with a die lip gap of 1.5–2.0 mm, a blow-up ratio of 3.0:1–4.0:1, and frost-line height 6–10 die diameters, followed by corona treatment to 38–42 mN/m for flexographic surface printing on one face. Compliance for placed-on-market packaging is documented under Directive 94/62/EC as amended, with combined lead, cadmium, mercury, and hexavalent chromium content not exceeding 100 ppm by weight in the packaging material, tested under the harmonized composition requirements of EN 13428:2004 with substance-specific analytical protocols; REACH candidate list substances are screened at 0.1 wt% under EC 1907/2006. Downstream bag making is performed on bottom-seal or side-seal machines at 80–120 cycles/min, with seal temperature and dwell time set to produce seal strength above 3 N/15 mm as measured per ASTM F88/F88M-23. Terminal formats include T-shirt carrier bags at 15–25 µm, boutique bags at 30–50 µm, produce bags, and mail order films or document envelopes at 25–60 µm. Film containing recycled LLDPE above 30 wt% is checked for gel particles and print adhesion failures because offline flexo stations show increased skipping when surface tension drops below 36 mN/m during storage. Converters also monitor seal bar temperature uniformity across the bag width with an infrared pyrometer array; surface temperature deviation greater than ±5°C across the seal bar produces inconsistent seal strength and is corrected before production restart.