In three-layer machine-grade pallet stretch film production, Braskem LF118 with nominal density 0.918 g/cm³ per ISO 1183-1 and melt mass-flow rate 1.0 g/10 min per ISO 1133-1 is typically assigned to the core layer at 70–85 wt% when skin layers are compounded with metallocene polyolefin plastomer or ethylene-vinyl acetate at 10–20 wt% to control cling and puncture. The formulation may include polyisobutylene or hydrogenated tackifier at 1.0–2.5 wt% in the skin layer and slip/antiblock masterbatch at 1.0–3.0 wt%; the core layer is usually free of migratory cling additives to preserve modulus. Compliance for non-food industrial wraps references REACH EC No 1907/2006 and the Packaging and Packaging Waste Directive 94/62/EC, while optional food-contact use must follow FDA 21 CFR 177.1520(c) olefin polymer provisions and EU 10/2011 overall migration limits of 10 mg/dm². Extrusion is performed on a three-layer coextrusion blown-film line with die diameter 200–350 mm, die gap 1.8–2.4 mm, blow-up ratio 2.5–3.2, internal bubble cooling, frost line height 500–900 mm, and melt temperature 200–230°C. The winding section uses tapered tension of 10–30% and oscillating haul-off to distribute gauge bands. Machine stretch film is produced at 12–23 µm gauge; pre-stretched hand film at 6–10 µm; vented pallet wrap and extended-core rewind variants are also produced from the same line. Puncture resistance is assessed by ASTM D5748, machine-direction stretch recovery by ASTM D5459, and tensile elongation at break by ISO 527-3; at 23 µm, converters commonly specify machine-direction ultimate elongation above 400% and puncture energy at maximum load above 0.4 J, though published data for this specific configuration is limited and line trials are required to confirm additive interactions.

Which compliance framework governs frozen-food contact films produced from LF118?

Frozen-food contact films using LF118 fall under EU 10/2011 with overall migration limit 10 mg/dm² and specific migration limits for slip and antiblock additives, and under FDA 21 CFR 177.1520(c) for olefin polymers when the applicable food-type extraction protocol is selected. The resin is typically formulated at 60–80 wt% LF118, 10–25 wt% low-density polyethylene for bubble stability, and 5–15 wt% metallocene LLDPE for low-temperature dart impact. Slip agent is added at 500–1,500 ppm, antiblock at 1,000–2,500 ppm, and fluoropolymer process aid at 200–600 ppm. Processing on monolayer or three-layer blown-film equipment uses die gap 1.2–2.0 mm, blow-up ratio 2.0–2.8, melt temperature 180–210°C, frost line height 300–600 mm, and internal bubble cooling; the lower melt temperature suppresses haze but increases die lip plate-out when high-slip masterbatch exceeds 1,500 ppm, shortening die cleaning intervals below 72 h. Finished types are pillow pouches, wicket bags for frozen vegetables, side-gusset seafood bags, and lidding film base webs in 25–80 µm gauge. Low-temperature dart impact is tested per ASTM D1709 Method A after 24 h conditioning at -20°C; tear propagation is measured per ISO 6383-2; and heat-seal strength is measured per ASTM F88, with typical target heat-seal strength above 15 N/25 mm at 130°C seal bar temperature for 0.3 s dwell.

Extrusion die geometry, gauge variance, and dart impact in heavy-duty industrial sacks

High-stalk blown-film extrusion of heavy-duty industrial sacks using LF118 requires a die diameter between 200 mm and 500 mm and a die gap of 1.6–2.4 mm to balance gauge uniformity against shear heating. The formulation range is 75–100 wt% LF118, 0–20 wt% low-density polyethylene to modify melt strength, carbon black or titanium dioxide masterbatch at 2.0–5.0 wt% for opacity and ultraviolet opacity, and polymer processing aid at 200–800 ppm to delay melt fracture. Compliance is defined primarily by tensile properties per ISO 527-3, tear resistance per ISO 6383-2, dart impact per ASTM D1709 Method B, and heavy-metal limits under REACH EC No 1907/2006; where sacks are used as FIBC liners, converter specifications often reference ISO 21898 for filled bag handling tests. Processing on a high-stalk line uses blow-up ratio 2.2–2.8, melt temperature 200–230°C, internal bubble cooling set to maintain frost line height within ±50 mm of the nominal 600–1,200 mm position, and capacitive gauge scanning with a control tolerance of ±5%. At melt temperatures above 230°C, the melt strength of LF118 declines and bubble sag increases; below 200°C, die pressure near 350 bar may appear at high output with narrow die gap, producing shark-skin unless the process aid is maintained. Finished products include FIBC liner film in 80–150 µm, form-fill-seal heavy-duty sacks in 60–120 µm, industrial refuse sacks in 40–80 µm, and construction debris bags. Dart impact targets at 100 µm are commonly set above 400 g per ASTM D1709 Method B, but published data for this specific LF118 blend configuration is limited, so converter trials must confirm the effect of carbon black dispersion and high-stalk residence time on impact distribution.

When silage film must retain puncture resistance after 18 months of UV exposure

Agricultural silage and greenhouse film formulations using LF118 place the resin at 65–85 wt% with low-density polyethylene at 5–15 wt%, carbon black masterbatch at 2.0–4.0 wt% for black/white or black/green silage covers, or hindered amine light stabilizer and UV absorber masterbatch at 1.0–3.0 wt% for clear greenhouse films. Processing involves wide-web blown-film extrusion with die diameter from 600 mm to 2,000 mm, die gap 2.0–2.6 mm, blow-up ratio 2.5–3.5, melt temperature 190–220°C, and internal bubble cooling with frost line height 800–1,500 mm to stabilize wide bubble geometry. Compliance is anchored to EN 13206:2017 for agricultural covering films, ISO 4892-2 for xenon-arc accelerated weathering, ISO 527-3 for tensile properties, and ISO 6383-2 for tear propagation. Finished types include bunker silo cover film in 100–150 µm, bale wrap film in 25–40 µm, greenhouse glazing film in 150–200 µm, and mini-tunnel mulch film in 25–50 µm. Retained elongation at break after 3,000 h xenon-arc exposure per ISO 4892-2 is typically specified at ≥50% for clear greenhouse film; for black silage film, cover durability is classified under EN 13206 by accelerated weathering and puncture resistance requirements, but because the specific stabilization masterbatch concentration interacts with LF118 comonomer distribution and film crystallinity, published data for this exact formulation is limited and outdoor exposure trials under local conditions are required.

For extrusion-laminated and adhesive-laminated flexible packaging structures, LF118 is introduced into the blown sealant web at 50–70 wt% with metallocene LLDPE or ethylene-vinyl acetate at 20–30 wt% to reduce heat-seal initiation temperature below 110°C under ASTM F1921 hot-tack test conditions and with low-density polyethylene at 5–10 wt% for neck-in control during subsequent extrusion lamination. The blown-film line operates at die gap 1.4–2.0 mm, blow-up ratio 2.0–2.5, melt temperature 190–220°C, and corona treatment at 38–42 mN/m to ensure adhesive anchorage. Compliance for food-contact pouches requires EU 10/2011 and FDA 21 CFR 177.1520(c), while overall packaging regulations include REACH EC No 1907/2006 and the Packaging and Packaging Waste Directive 94/62/EC; migration testing is conducted according to the EN 1186 series. Finished types are stand-up pouches, three-side-seal sachets, lidding films, and medical device overwrap when biocompatible additives are selected. Heat-seal strength per ASTM F88 at 130°C seal bar temperature and 0.3 s dwell is usually specified at ≥15 N/25 mm for a 70 µm web, while hot-tack strength per ASTM F1921 is specified only for high-speed vertical form-fill-seal applications. Corona treatment above 42 mN/m can reduce hot-tack performance by increasing surface polarity and seal initiation variability; therefore, inline surface tension monitoring is required.