On high-output monolayer blown-film lines producing heavy-duty industrial sacks from 25 kg to 50 kg and FIBC inner liners up to 1,500 kg, Braskem LL6901S is processed as a butene comonomer linear low density polyethylene with a nominal melt flow rate of 1.0 g/10 min (ISO 1133-1:2022) and a density of 0.920 g/cm³ (ISO 1183-1:2019). The base formulation is either 100 wt% LL6901S or an 80/20 wt% blend with high-pressure LDPE when older air-cooled lines without dual-lip air rings require higher melt strength; anti-block masterbatch is introduced at 0.5–1.5 wt% and slip masterbatch at 0.5–2.0 wt% only when the coefficient of friction must remain below 0.35 under ISO 8295:1995 after a conditioning period of 24 h. Slip addition is treated as a migration-controlled variable because low-molecular-weight erucamide or oleamide concentrates migrate to the film surface within 24–72 h after winding, so friction results taken immediately off-line underreport the final surface slip and can lead to over-treatment if the converter compensates too early. The extrusion process for sacks and FIBC liners uses a grooved-feed single-screw extruder with a screw L/D ratio of 24:1 to 30:1 and a barrel diameter from 55 mm to 90 mm, feeding a die head of 150 mm to 400 mm diameter; the die gap is held at 1.6–2.5 mm, the blow-up ratio from 2.0:1 to 3.0:1, and the frost line height at 600–900 mm above the die to avoid bubble instability caused by excessive cooling or excessive film tension. Barrel temperatures are profiled from 160°C at the feed zone to 200–215°C at the adapter and die, while the die lip temperature is trimmed by ±3°C across multiple zones to maintain gauge variation below ±5% on the final web. Inner bubble cooling is engaged only when line speed exceeds 35 m/min, because the higher melt viscosity of LLDPE increases heat load inside the bubble and can otherwise cause blocking and coefficient-of-friction drift. If melt pressure approaches 320 bar at the breaker plate, a fluoropolymer processing aid is added at 200–400 ppm to eliminate sharkskin and delay die-lip deposit formation; the processing aid is introduced as a masterbatch at 1–2 wt% of total feed and is confirmed by pressure reduction on the extruder head. Compliance anchors for industrial sacks are set by ISO 21898:2004 for FIBC safety and, when the sack carries hazardous solids, by the applicable UN dangerous goods packaging performance provisions for flexible containers; carbon black masterbatch for outdoor resistance is added at 1.5–3.0 wt% and dispersion is checked by ASTM D5596. Terminal products include FIBC inner liners, valve bags for polymer granulate and chemical powders, mineral-filled sacks at 50 kg, construction rubble bags, and liners for corrugated boxes containing granular fertilizer or hydrated lime.

At −20°C, What Requires Frozen Food Film Converters to Replace Standard LDPE with Butene LLDPE Blown Film?

When vertical form-fill-seal lines run frozen vegetable, seafood, and prepared frozen food film at packaging hall temperatures below −18°C, the controlling film properties shift from room-temperature tensile yield to low-temperature dart impact and machine-direction Elmendorf tear because the web must survive both the freezing tunnel and the dropping of the filled package onto concrete floors. LL6901S is selected for these structures because the butene comonomer distribution in the linear low density polyethylene backbone produces a lower brittle point than an LDPE homopolymer of equivalent density, although converters must not extend that conclusion to extremely low abuse conditions where an octene LLDPE or a higher molecular weight copolymer is required. The food-contact basis for the sealant layer is verified under FDA 21 CFR 177.1520 for olefin polymers and, for the European market, under Commission Regulation (EU) No 10/2011 as amended with overall migration and specific migration limits checked using the appropriate food simulant for the intended frozen food category; the converting plant is also required to operate under EC No 2023/2006 GMP. A typical three-layer frozen food film places LL6901S at 70–85 wt% of the food-contact sealant layer, with the balance as 15–30 wt% LDPE for bubble stability or plastomer of density 0.900–0.910 g/cm³ when the converter wishes to lower seal initiation below 95°C; anti-block and slip masterbatches are limited to a combined 0.3–0.8 wt% to avoid seal contamination and off-flavour transfer. In the core layer, LLDPE/LDPE ratios from 30/70 wt% to 50/50 wt% are used to keep the bubble symmetrical at wide gusseted formats. The downstream process is a three-layer blown-film line with individual extruders feeding a die head of 200–350 mm diameter, a die gap of 1.8–2.2 mm for the LLDPE-dominant layers, a blow-up ratio of 2.5:1 to 3.0:1, and melt temperatures of 180–205°C in the LLDPE layers to limit low-temperature additive degradation. The bubble is quenched with chilled air at 8–12°C and a frost line height of 700–1,000 mm; the resulting film is flatted over collapsing frames with low-contact rollers to reduce gusset wrinkles, and the outside surface is corona-treated to 38–42 dyne/cm before flexographic or rotogravure printing. Terminal products include pillow pouches for frozen spinach and IQF vegetables, side-seal bags for frozen seafood, overwrap for block frozen meat, gusseted bags for frozen fruit blends, and printed laminates for ready-to-bake frozen meals, with total film thickness generally in the 40–60 µm range. Published data for LL6901S specifically in corn-based frozen food film structures is limited; instrumented dart impact testing at −20°C under ASTM D1709-22 Type B and tear testing under ASTM D1922-15 must therefore be performed on production film before approval of the grade in a line already tuned for another LLDPE.

Protected-cropping film lines serving southern European and North African tunnel agriculture process LL6901S when a lower-cost butene LLDPE base is required for multilayer greenhouse side sheets and low tunnels intended for service of 12–24 months under ultraviolet exposure. Compliance for this segment is defined by EN 13206:2017 for agricultural covering films, and the converter must validate that UV stabilizers and anti-drip additives do not release substances to crops in quantities prohibited by national food safety laws where the film touches leafy vegetables. At the compounding or dosing stage, the resin is introduced as 100 parts by weight base polymer; a hindered amine light stabilizer masterbatch is added at 3–5 wt%, a UV absorber masterbatch at 0.5–1.5 wt%, and an anti-fog/anti-drip concentrate at 0.8–2.0 wt% only in the crop-facing inner layer to control water droplet formation. The extrusion process for greenhouse side sheeting uses a three-layer blown-film line with a die diameter of 250–500 mm, a die gap of 1.8–2.4 mm, a blow-up ratio of 2.0:1 to 2.5:1, and a frost line height of 800–1,200 mm above the die; the side-layer extruders run at 150–180 rpm and melt temperatures of 190–210°C, while the dual-lip air ring is controlled so that the air velocity does not quench the bubble too early and create machine-direction tear weakness. Because the grade has a melt flow rate of 1.0 g/10 min, it produces a stable bubble at wide layflat widths, but draw resonance can appear when the frost line is raised too far or when online thickness variation exceeds ±5% on capacitance gauges; the extruder operator therefore maintains a stable neck height and reduces take-off ratio when the bubble begins to breathe. In black/white coextruded mulch film, LL6901S occupies the black inner layer at 100 wt% of that layer with carbon black masterbatch at 3–5 wt%, while the white reflecting outer layer is run with white pigment masterbatch at 8–12 wt% and a different LDPE-rich formulation to maintain opacity. Terminal product types include low-tunnel cover films of 60–100 µm, greenhouse side sheets of 100–180 µm, black/white mulch films of 20–40 µm, and nursery overwrap where high diffuse light transmission is not the primary specification. The use of recycled LLDPE in these agricultural films is restricted by the EN 13206:2017 performance requirements and by national schemes for agricultural plastics waste collection.

Pallet Wrap Edge Tear Resistance and Down-Gauging Limits on Air-Cooled Monolayer Blown Lines

On blown-film stretch wrapping lines where manual pallet wrap is sold on edge tear resistance and load holding rather than high clarity, LL6901S is extruded at 18–25 µm and measured under ASTM D5748-95 for puncture, ASTM D5458-95 for cling, and ASTM D882-18 for tensile elongation. The nominal melt flow rate of 1.0 g/10 min gives higher melt strength than cast stretch grades, but it also limits motor load on shallow-flighted extruders: on a 45–65 mm smooth-bore extruder with L/D of 24:1, the melt temperature is kept between 195°C and 210°C and the head pressure is held below 300 bar to avoid shear gels and die deposits. Formulation routes for blown stretch film use LL6901S at 100 wt% as the base resin, with polyisobutylene cling masterbatch at 1–2 wt% or a migratory cling additive at 0.5–1.2 wt%, plus a low-slip anti-block adjustment if the winder tension is high enough to strip the cling surface; total additive loading is kept below 3 wt% to maintain hot tack and to avoid excessive bloom that changes unwind force with age. The blown-film line uses a die gap of 1.5–2.0 mm, a blow-up ratio of 2.0:1 to 2.8:1, and a frost line height of 650–900 mm, with two-stage air flow to reduce blocking before the collapsing frame and a winding tension taper from 200 N/m at the core to 80 N/m at the outer wrap to prevent telescoping. The major processing threshold in down-gauging below 20 µm is the onset of transverse-direction tear weakness where the frosted bubble loses gauge uniformity and the film becomes sensitive to edge cuts from hand dispensers; converters therefore inspect edge tear by ASTM D1922-15 on both machine and transverse directions and reject rolls outside the internal specification before shipment. Terminal product types include hand pallet wrap for warehouse loading docks, gusseted bundling film, and industrial coil wrap for hardware distribution, but blown-film haze and gauge variability at 18 µm restrict use in retail display films where high gloss is the primary specification. In food-sector pallet wrapping where the film is secondary packaging, the resin permits a food-contact statement under FDA 21 CFR 177.1520 and EU No 10/2011 subject to converter end-use verification; for industrial non-food loads, the performance specification is anchored to ASTM D5458-95 and ASTM D882-18.

Coextruded lamination sealant webs for dry food and detergent pouch converting are produced with LL6901S in the heat-seal layer at 70–80 wt% of that layer’s formulation, balanced by 20–30 wt% of a lower-melting plastomer to bring the seal initiation temperature below 100°C without reducing the hot-tack plateau too far. The core layer, which is typically 20–35 wt% of total film thickness, is run with LDPE or an LLDPE/LDPE blend to manage stiffness and bending recovery, while the outer print layer receives corona treatment. Food-contact compliance in the European Union for this sealant web is established under EU No 10/2011 with migration testing in food simulant E for dry foods and in food simulant D2 for fatty foods where the film will seal fatty dry mixes; the United States route is FDA 21 CFR 177.1520 for the olefin polymer and 21 CFR 176.170(c) where the film is part of a laminated structure that contacts aqueous or fatty food through paper or aluminium foil. Manufacturing is carried out under EC No 2023/2006 GMP. The blown-film process for these sealant webs uses three extruders feeding a die head of 180–350 mm diameter, a die gap of 2.0–2.5 mm for the LLDPE-dominant layer, a blow-up ratio of 2.5:1, and melt temperatures of 185–210°C in the sealant extruder; internal bubble cooling is used to strip heat from the high-viscosity LLDPE layer and to reduce blocking on the nip. After slitting, the treated outer web is laminated to printed paper, aluminium foil, or metallised polyester using solvent-free adhesives, and the sealant layer is not corona treated on the food-contact side to avoid sealant degradation. Terminal product types include the inner sealant web in printed paper/PE pouches for cake mixes and instant powders, the inner layer of foil/PE laminates for dry soups and beverage premixes, and the sealant layer in three-layer coextruded film later laminated to metallised polyester for high-barrier dry food packages. In these structures LL6901S does not provide oxygen or moisture barrier; the barrier is supplied by the foil or metallised layer, while the LLDPE layer contributes seal strength, film toughness, and the ability to seal through small powder particles.

If Reclaimed LDPE Film Waste Is Introduced at 50 wt% in Refuse Sack Extrusion

When post-industrial film scrap or recycled LDPE is introduced at 50 wt% into refuse-sack and industrial-liner extrusion, LL6901S functions as the virgin let-down resin that restores machine-direction Elmendorf tear and dart impact values lost after repeated heat histories in the recyclate. The recycled stream is first sorted, agglomerated, and re-extruded through a continuous melt filter with 100–150 mesh screens to remove gels, paper fragments, and aluminium residues; the virgin addition is set between 30 wt% and 50 wt% LL6901S with 50–70 wt% recycled LDPE and adjusted until the final film meets the converter’s internal specification under ASTM D1709-22 and ASTM D1922-15 at 30–80 µm thickness. Because the recycled fraction carries unknown additive histories, the converter must manage viscosity by adding 5–10% additional internal lubricant or process aid when extruder head pressure fluctuates beyond ±15 bar during a batch run. Compliance for recycled-content films placed on the European market requires conformity to Directive 94/62/EC packaging waste provisions and traceability of the recyclate under EN 15343:2007; since the film is non-food-contact, it remains outside EU No 10/2011, but REACH restrictions on substances of very high concern still apply to the recycled feedstock. The blown-film line for refuse sacks uses a grooved-feed extruder with an L/D ratio of 30:1, a die gap of 1.8–2.5 mm, a blow-up ratio of 2.5:1 to 3.5:1, and a melt temperature of 175–200°C; the lower melt temperature reduces thermal degradation and odour formation in the recycled fraction but raises melt viscosity, so a gear pump is installed between the extruder and die to sustain output above 80 kg/h while filtering the melt. The gear pump also reduces screw surging and film thickness variation, preventing weak spots along the side walls where refuse sacks fail during compaction. Terminal product types include refuse sacks from 30 L to 120 L capacity, can liners, industrial waste bags, and flat film for construction dust barriers, with load retention and tear resistance checked by the converter because no single global standard covers all municipal and industrial waste bag grades. The main operational boundary is the maximum recycled content at which the blend retains puncture resistance: if the recyclate contains heavily degraded LDPE with a melt flow rate above 2.0 g/10 min, the LL6901S virgin content should be increased toward 50 wt% or the film thickness raised to compensate.