Where the specific datasheet for Braskem LBH0120PBS is not cited, the processing windows below are drawn from the industrial class of butene-copolymer LLDPE blown-film grades with nominal density near 0.920 g/cm³ and melt flow rate in the 0.9–1.1 g/10 min band under ASTM D1238 (190 °C/2.16 kg). In blown-film production of agricultural silage covers and greenhouse side sheeting, the converter must resolve a conflict between long-term UV stabilisation and melt-process stability because the HALS package that provides multi-season weathering protection also increases melt viscosity and narrows bubble-stability margins. Industrial lines for this material class typically run single-screw extruders with a 30:1 L/D barrier screw containing a Maddock mixing section, a die diameter from 250 mm to 350 mm, and a die gap from 1.8 mm to 2.2 mm. Melt temperature is maintained between 210 °C and 240 °C; blow-up ratio is held at 2.0:1 to 2.8:1; frost line height is set from 600 mm to 900 mm above the die face. Gravimetric blenders meter a UV masterbatch to yield HALS levels of 2,500–6,000 ppm, UV absorber levels of 1,500–3,000 ppm, silica antiblock at 2,000–4,000 ppm, and erucamide slip at 500–1,000 ppm. Above 4,000 ppm HALS, die pressure increases and the bubble becomes more sensitive to ambient air fluctuations; widening the die gap to 2.2 mm and lowering melt temperature toward 210 °C reduce shear heat without sacrificing additive dispersion. Gauge control uses capacitance sensors at the layflat, and tensile properties are tested under ISO 527-3, tear resistance under ISO 6383-2, dart impact under ASTM D1709 Method A, and weathering retention under EN 13206:2017 protocols for agricultural covering films. Accelerated weathering may also be screened under ASTM G154. REACH SVHC screening applies to EU-bound finished film. Terminal articles include silage clamp covers, tunnel greenhouse side sheeting, round-bale storage bags, and mulch-cover overwrap where gauge exceeds 80 µm.

Why Does Bubble Stability Govern Heavy-Duty Shipping Sack Output?

Heavy-duty shipping sack extrusion targets high dart-impact and tear-propagation resistance without excessive blocking on the winder. Butene-copolymer LLDPE tolerates greater bubble deformation than metallocene grades before melt fracture, but its lower melt tension makes frost-line position the primary control for gauge uniformity. Converters running tubular-quench lines with die diameters of 200–300 mm and die gaps of 2.0–2.4 mm usually set blow-up ratio at 2.5:1 to 3.0:1 and maintain melt temperatures between 215 °C and 230 °C. A 90 mm single-screw extruder with 30:1 L/D can sustain outputs of 180–250 kg/h in this process window, with die pressure typically held at 300–400 bar through screen-pack selection. Silica antiblock at 2,000–4,000 ppm and erucamide slip at 500–1,000 ppm are metered in; beyond 5,000 ppm silica, dart impact for 50 µm film can drop from the 80–120 g range typical of this polymer class toward 60–80 g because antiblock particles act as stress concentrators. Dart impact is measured under ASTM D1709 Method A, Elmendorf tear under ASTM D1922, tensile modulus and elongation under ASTM D882, and coefficient of friction under ASTM D1894. The main quality failure mode is a low machine-direction tear value relative to transverse direction, which appears when the frost line is too high and molecular orientation relaxes in the machine direction; operators restore the ratio by lowering the air-ring chiller setpoint and increasing blow-up ratio within the upper limit. Industrial sacks are subject to heavy-metal limits under EU 94/62/EC Annex II and U.S. CONEG model legislation. Terminal articles include valve sacks, open-mouth shipping sacks, bag-in-box inner liners for industrial fills, and industrial form-fill-seal bags.

On high-speed collation-shrink lines for beverage multipacks, the blown-film converter shifts from puncture resistance toward controlled shrink, low blocking, and consistent shrink force. The web must pass through a hot-air tunnel at line speeds above 30 m/min and shrink around cans or bottles without tearing at corner geometries. Film is produced at 45–70 µm with a die gap of 1.6–2.0 mm, a blow-up ratio of 3.0:1, and a frost line height held between 450 mm and 700 mm. The high hoop orientation obtained at this BUR is necessary to reach transverse free-shrink levels above 60% under ASTM D2732 at 130 °C; machine-direction shrink is kept below 45% to avoid tall-pack distortion. Shrink force and release stress are measured under ASTM D2838 to control tunnel dwell time. Erucamide slip is reduced to 300–600 ppm to prevent lubricant bloom from reducing shrink force, and antistatic masterbatch is added at 500–1,500 ppm to assist collation laning. A frost-line height above 3 die diameters allows molecular relaxation and lowers transverse shrink; an excessively low frost line increases blocking and uneven shrink force across the width. Secondary packaging for beverage multipacks is not direct food contact but must meet EU 94/62/EC Annex II heavy-metal limits and REACH SVHC disclosure for EU supply. Terminal articles are collation shrink bundling film, shrink sleeve bundling for PET bottles, and multipack wrap for beverage cans.

When Frost Line Height Falls Below Three Die Diameters in Frozen Food Overwrap

Frozen food overwrap reaches a low-temperature seal-strength and puncture-resistance boundary where frost-line position relative to die diameter is the critical process variable. If the frost line falls below 3 die diameters, the quenched bubble retains excessive orientation and may become brittle at freezer temperatures; if it rises too high, optical haze increases and seal initiation widens. Blown-film lines running 25–50 µm overwrap use extruder L/D of 25:1 to 30:1, die gap 1.6–2.0 mm, BUR 2.5:1, and melt temperature 200–225 °C. Slip and antiblock loadings are lower than industrial sacks: erucamide 400–800 ppm and synthetic silica 1,500–3,000 ppm maintain machinability while preserving heat-seal strength. Low-temperature brittleness is measured under ASTM D1790, seal strength under ASTM F88, puncture resistance under ASTM D5748, and dart impact under ASTM D1709. Food-contact compliance requires FDA 21 CFR 177.1520(c) for olefin polymers and EU 10/2011 migration testing with aqueous and fatty simulants appropriate to the intended frozen-food types. Published data for this specific configuration is limited; converters should conduct seal-strength and migration testing on the final structure at sub-zero storage temperatures, particularly for high-fat frozen products where simulant D2 or vegetable-oil substitutes are specified. Terminal articles include frozen vegetable bags, freezer film, frozen seafood overwrap, and carton-overwrap film for frozen food.

Lamination-grade sealant webs for PET/aluminium/LLDPE pouches require a surface that reaches and holds a corona treatment level of 38–42 dyn/cm under ASTM D2578 while retaining a low coefficient of friction after winding. The sealant web is produced as a monolayer or coextruded layer at 25–50 µm, with die gap 1.6–2.0 mm, BUR 2.2:1 to 2.6:1, and melt temperature 205–225 °C. Erucamide slip is kept to 300–700 ppm, synthetic silica antiblock at 1,000–2,500 ppm, and polymer processing aid at 200–600 ppm to delay melt fracture during thin-gauge extrusion. The principal process conflict occurs during corona treatment: oxidation raises surface energy for adhesive lamination but can degrade migratory slip molecules on the treated surface, raising kinetic coefficient of friction by more than 0.10 in ASTM D1894 sled tests if the treater power is too aggressive. Seal initiation temperature and heat-seal strength are measured under ASTM F88, hot-tack under ASTM F1921, and surface treatment under ASTM D2578. Direct food-contact compliance for the final laminate is evaluated under FDA 21 CFR 177.1520(c) and EU 10/2011; REACH SVHC declarations are required for EU supply. Terminal articles include stand-up pouches, coffee-bag lamination, snack-food laminates, and non-retort pouch structures where the LLDPE sealant layer provides seal integrity below 100 °C.

No Internal Bubble Cooling for High-Slip Industrial Liner Films

Industrial liner films extruded without internal bubble cooling rely entirely on the external air ring for melt solidification; this restricts heat-transfer rate and makes frost-line position the limiting factor for output and gauge uniformity at heavy thickness. For liners of 100–200 µm used inside fibre drums, corrugated boxes, and FIBC inserts, the process typically starts with a single-screw extruder of 30:1 L/D, a die diameter of 250–400 mm, die gap 2.0–2.4 mm, BUR 2.0:1 to 2.5:1, and melt temperature 210–235 °C. Without internal bubble cooling, raising output above the air-ring capacity generates a high frost line and causes web wander; lowering output to stabilise the bubble increases residence time and can over-degrade the slip additive if melt temperature is not reduced concurrently. Erucamide slip at 700–1,000 ppm and silica antiblock at 2,500–5,000 ppm are used to achieve low insertion force into boxes and drums, with coefficient of friction monitored under ASTM D1894. Industrial liners do not normally require food-contact registration unless the filled product is food; heavy-metal limits under EU 94/62/EC Annex II and the U.S. CONEG model apply. Mechanical acceptance tests include dart impact under ASTM D1709, Elmendorf tear under ASTM D1922, tensile properties under ASTM D882, and conditioning under ISO 291. Terminal articles include FIBC liners, fibre-drum liners, corrugated-box liners, and chemical bag liners.

The compliance matrix below consolidates the principal regulatory anchors and test methods for the downstream contexts described above.

Application context	Regulatory anchor	Key test methods	Typical additive constraint
Agricultural silage cover	EN 13206:2017, REACH SVHC	ISO 527-3, ISO 6383-2, ASTM D1709, ASTM G154	HALS 2,500–6,000 ppm, silica 2,000–4,000 ppm
Heavy-duty shipping sack	EU 94/62/EC Annex II, CONEG	ASTM D1709, ASTM D1922, ASTM D882, ASTM D1894	Silica 2,000–4,000 ppm, erucamide 500–1,000 ppm
Collation shrink film	EU 94/62/EC Annex II, REACH SVHC	ASTM D2732, ASTM D2838	Erucamide 300–600 ppm, antistatic 500–1,500 ppm
Frozen food overwrap	FDA 21 CFR 177.1520(c), EU 10/2011	ASTM D1790, ASTM F88, ASTM D5748, ASTM D1709	Erucamide 400–800 ppm, silica 1,500–3,000 ppm
Lamination sealant web	FDA 21 CFR 177.1520(c), EU 10/2011, REACH SVHC	ASTM D2578, ASTM F88, ASTM F1921, ASTM D1894	Erucamide 300–700 ppm, silica 1,000–2,500 ppm
Industrial liner film	EU 94/62/EC Annex II, CONEG	ASTM D1709, ASTM D1922, ASTM D882, ASTM D1894, ISO 291	Erucamide 700–1,000 ppm, silica 2,500–5,000 ppm