Braskem LL6800N is a butene-comonomer linear low-density polyethylene with nominal density 0.918 g/cm³ (ASTM D1505) and melt flow rate 1.0 g/10 min (ASTM D1238, 190°C/2.16 kg). The application scenarios below are limited to blown film downstream sectors with documented use of C₄-LLDPE in this density and MFR envelope; cast film, injection moulding, and rotational moulding claims are not included.

What Melt Temperature Window Suppresses Melt Fracture in Monolayer Heavy-Duty Sack Film?

On monolayer heavy-duty sack lines using 50 mm grooved-feed extruders with 30:1 L/D barrier screws, LL6800N is metered at 70–85 wt% alongside a fractional-MFI LDPE homopolymer at 15–30 wt%; 100 wt% LL6800N operation is limited to dies above 200 mm with internal bubble cooling because neck-in and bubble flutter become critical below 2.0 blow-up ratio. Compliance for sacks carrying granular chemicals includes UN 5H4 plastics film bag certification under the UN Model Regulations, with drop-test and stack-test acceptance determined on the finished sack structure rather than on resin pellets; ASTM D1709 dart impact, ASTM D1922 Elmendorf tear, and ASTM D882 tensile properties are specified at finished gauge. Extrusion uses melt temperatures of 195–210°C, die gap 1.8–2.4 mm, blow-up ratio 2.0–2.8, and frost line height 350–600 mm. Die lip fouling from oxidized material appears when melt temperature exceeds 220°C for more than 30 min, producing gel clusters in the film; screen packs of 60/80/100 mesh are changed when back pressure exceeds 380 bar. Terminal products include 25 kg resin sacks, 50 kg chemical sacks, and FIBC inner liners. Pre-drying is not required unless pellet surface moisture exceeds 0.02 wt% after outdoor silo storage; in that condition, hopper drying at 60°C for 2 h prevents micro-pinholes.

In a three-layer agricultural film line with a 350 mm spiral mandrel die and 65 mm grooved-feed extruders, LL6800N is placed in the black core layer at 35–50 wt% with carbon black masterbatch at 3–5 wt%; outer white layers use a UV-stabilised LDPE or EVA carrier. Compliance follows EN 13206:2017 for thermoplastic agricultural films, including tensile and tear propagation after artificial ageing. Extrusion conditions are die gap 2.0 mm, blow-up ratio 2.0–2.5, output 300–400 kg/h, and melt temperature 190–205°C. The main processing conflict is carbon black dispersion: poorly dispersed masterbatch creates specks and weak tear paths, so screen packs of 60/80/100 mesh are kept below 350 bar to avoid excessive back pressure. Terminal film types are silage clamp covers, temporary silage pit sheets, and greenhouse ground cover, in thicknesses from 100 µm to 200 µm.

Frozen Food Pouch Film with a 100% LL6800N Sealant Skin

Three-layer coextrusion lines producing frozen food pouches use LL6800N as the sealant skin at 70–100 wt% of the outer layer; the core may contain LDPE or HDPE for stiffness. Food-contact compliance is determined on the finished film under FDA 21 CFR 177.1520(c) for olefin polymers and Regulation (EU) No 10/2011 Annex I, with overall migration not exceeding 10 mg/dm² under conditions of use for frozen storage below −18°C. The seal layer thickness is typically 15–20 µm of a total 60 µm film; the line runs at melt temperature 190–205°C, die gap 1.5–2.0 mm, blow-up ratio 2.2–2.8, and frost line height 250–350 mm. Seal initiation on the packing line is monitored because lot-to-lot MFR drift of 0.1 g/10 min shifts the seal bar temperature requirement by 2–4°C; converters set seal jaw temperature 5°C above the DSC endset of the film, and seal strength is measured to ASTM F88. Terminal finished products include vegetable pouches, frozen seafood bags, and ice cream overwrap. The operational boundary is the sealant skin thickness: below 12 µm, seal integrity becomes sensitive to filler-level variation in the core, and above 25 µm, film blocking at rewind temperatures above 30°C increases defect rates.

Stretch hood conversion requires a film that combines machine-direction elastic recovery with puncture resistance on pallet corners. LL6800N is blended at 50–70 wt% with LDPE film resin at 20–40 wt% and a metallocene LLDPE at 5–10 wt% to move stretch holding force into the documented range for pallet stability. Compliance for stretch hood films is handled via ASTM D5459 for machine direction elastic recovery and permanent deformation, with puncture resistance reported under internal methods derived from ISO 7765-1. Extrusion uses a 2.0–2.4 mm die gap, blow-up ratio 2.5–3.0, melt temperature 190–210°C, and internal bubble cooling to raise output; gauge variation is held within ±4% by automatic die lip adjustment because uneven thickness causes telescoping in the winder. Terminal film types are pallet hood covers for chemical drums, heavy machinery covers, and export transit covers. The main operational boundary is winding tension: taper must be set to 30–50% at roll diameter buildup, and ambient warehouse temperature below 10°C should trigger a reduction in draw rate to avoid brittle unwind breaks.

When Post-Consumer rLLDPE Destabilises Can Liner Bubble Geometry

Blending post-consumer rLLDPE into can liner film at 20–40 wt% LL6800N fresh resin introduces bubble instability when the melt viscosity of the recyclate batch varies by more than 15% from the nominal MFR. Compliance is governed mainly by Directive 94/62/EC heavy metal limits, with lead, cadmium, mercury and hexavalent chromium totalling not more than 100 mg/kg in packaging components, and by REACH Regulation (EC) No 1907/2006 for substances of very high concern in recycled feedstocks. Extrusion conditions shift downward to melt temperatures of 180–200°C to suppress oxidative gel formation from residual PP or PE contaminants; screen packs of 60/80/100 mesh are installed and changed every 6–8 h when die lip deposits reduce bubble symmetry. Die gap is 2.0–2.4 mm, blow-up ratio 2.0–2.5, and a vacuum-vented single screw of 28:1 L/D pulls residual moisture from the recyclate. Terminal products include heavy-gauge trash can liners, institutional waste bags, and retail checkout bags. The operational boundary is extruder back pressure: if screen pressure exceeds 380 bar, melt temperature rises and film tear strength, measured to ASTM D1922, falls below release limits due to recycled resin degradation.

E-Commerce Courier Film C₄-LLDPE Substitution at 65 Micrometres

Courier mailer film at 65 µm is produced by dry blending LL6800N at 60–80 wt% with LDPE at 20–40 wt% and black masterbatch at 3–5 wt%; substituting LL6800N for 100 wt% LDPE constructions of the same gauge improves dart impact and tear propagation measured to ASTM D1709 and ASTM D1922 without changing the blown film line footprint. Regulatory compliance references Directive 94/62/EC heavy metal thresholds and the U.S. CONEG model legislation, with total lead, cadmium, mercury and hexavalent chromium below 100 mg/kg. Extrusion on a 65 mm grooved-feed extruder uses melt temperature 190–205°C, die gap 1.8–2.2 mm, blow-up ratio 2.5–3.0, and frost line height 300–450 mm; back pressure is maintained at 320–380 bar to keep output stable at 180–220 kg/h on a 400 mm die. Terminal finished products include courier mailer bags, document return envelopes, and garment poly bags. The main limitation is blocking in high-gloss black film at winding temperatures above 35°C; slip and antiblock packages are adjusted accordingly, but erucamide addition above 0.15 wt% may reduce seal strength on automated bag lines.