Inside the Silage Bale Wrapping Window at −10°C

Agricultural bale-wrap conversion of Braskem LHB 118/21 AF is typically run on a three-layer blown film line with screw diameters of 65/80/65 mm and 30:1 L/D, a 350 mm die diameter, 1.8–2.2 mm die gap, blow-up ratio of 2.5:1–3.0:1, and frost line height 800–1200 mm above the die face. Melt temperature is held between 190°C and 210°C, and die zones are set with a flat profile to avoid transverse-direction thickness bands that amplify during bale wrapping. The resin has a nominal density of 0.918 g/cm³ per ASTM D1505 and a melt flow rate of 1.0 g/10 min per ASTM D1238 at 190°C/2.16 kg. The hopper formulation is 100 phr LHB 118/21 AF with 1.0–2.5 wt% HALS/UV masterbatch, 0.5–1.2 wt% white TiO₂ masterbatch, and up to 15 wt% same-line edge-trim recycle. Finish-product compliance follows EN 13206:2017 for thermoplastic bale-wrap films, with tensile properties per ISO 527-3, tear propagation per ASTM D1922, and dart impact per ASTM D1709 Method A. The production-scale failure mode recorded on wrapping machines is not tensile yield but low-temperature flexing at fold lines when film temperature drops below −10°C; under those conditions transverse-direction tear resistance becomes the limiting property, and converters typically increase HALS addition toward the upper 2.5 wt% limit and reduce recycle content below 10 wt% to preserve fold-line integrity. Converted articles from this segment include 25–30 µm round-bale silage wrap, clamp silage sheets, silage bags, and grain storage covers.

Blown film lines producing freezer-grade packaging from LHB 118/21 AF operate with 1.8 mm die gap, 2.2:1–2.8:1 blow-up ratio, 195–215°C melt temperature, and corona treatment to 38–40 dyn/cm surface energy after bubble collapse. The web is run at 40–70 µm thickness; the frost line is held at 5–7 die diameters to prevent blocking between film plies before winding. Formulation addition ratio is 100 phr LHB 118/21 AF with 1.0–2.0 wt% of an antiblock/slip masterbatch; if bubble stability is insufficient on a given line, 10–20 wt% LDPE with melt flow rate 0.25 g/10 min is added. For food-contact use, compliance is evaluated under 21 CFR §177.1520 and Regulation (EU) No 10/2011; overall migration is limited to 10 mg/dm² using EN 1186-1 total immersion testing. The compliance matrix for this segment is summarized below.

Terminal finished product types include IQF vegetable pouches, frozen fruit bags, ice-glazed poultry packaging, and frozen dough liners. The primary sealing defect observed on vertical-form-fill-seal lines is channel leaker formation when sealant temperature falls below 105°C at 0.2–0.4 s dwell; converters therefore hold sealing jaw temperature between 110°C and 140°C. Cold-storage conditioning at −30°C for 24 h followed by drop testing is used to qualify bag toughness; published data for this specific LHB 118/21 AF configuration is limited, but the tests are specified in converter incoming inspections.

What Changes When Barrier Lamination Films Drop Below 12 µm?

The sealant web in a barrier laminate is converted from LHB 118/21 AF on a blown film line with 1.5–2.0 mm die gap, 2.0:1–2.5:1 blow-up ratio, and 190–210°C melt temperature. When target sealant thickness falls from 20 µm to 12 µm, the processing conflict shifts to hot-tack window and gauge uniformity; sealing jaw temperatures must remain between 110°C and 140°C, dwell time is shortened to 0.3–0.5 s, and any thickness deviation greater than ±1.0 µm produces channel leakers at the seal fold. The sealant formulation is 80–100 wt% LHB 118/21 AF with 0–20 wt% LDPE; a fluoroelastomer processing aid is added at 0.03–0.08 wt% to suppress melt fracture. Slip additives are omitted or limited to 0.2 wt% because migratory erucamide reduces bond strength after solventless adhesive lamination at 1.5–2.5 g/m² coat weight and 5–7 days cure at 35°C. Compliance is under FDA 21 CFR §177.1520 and Regulation (EU) No 10/2011; laminate seal strength is verified per ASTM F88/F88M. Converted laminates emerging from this process include stand-up pouches, pillow bags for dry snacks, sachet films, and lidding membranes.

Heavy-Duty Sack Fill-Spill Impact Testing

Industrial sacks produced from LHB 118/21 AF are blown as heavy-gauge tubular film at 80–200 µm thickness with 2.0–2.5 mm die gap, 1.8:1–2.2:1 blow-up ratio, and 200–220°C melt temperature. The lower blow-up ratio increases machine-direction stiffness and reduces transverse gauge variation before flexographic printing, gusseting, and bottom sealing. The blown film compound is 70–100 wt% LHB 118/21 AF with 0–30 wt% high-density polyethylene to raise secant modulus, plus 1–3 wt% white masterbatch for opacity. Where the converted sack functions as an inner liner for UN-certified FIBCs, the finished liner must pass stacking and drop tests referenced in ISO 21898:2004 and the applicable UN Recommendations on the Transport of Dangerous Goods Chapter 6.5; mechanical evaluation uses ISO 527-3, ASTM D1709, and ASTM D1922. The critical fill-spill test is conducted after conditioning at −20°C for 24 h; published data for this specific LHB 118/21 AF formulation is limited, but converter trials record failures at the gusset fold when dart impact value per ASTM D1709 Method A falls below the specification for the filled mass. Downstream sacks and liners produced in this segment include FIBC liners, chemical powder sacks, resin pellet bags, fertilizer sacks, and mineral aggregate bags.

On palletizing lines where a single tubular film is stretched over a load at pre-stretch ratios of 70–120%, LHB 118/21 AF is extruded on a three-layer blown film line with 2.2 mm die gap, 3.0:1–3.5:1 blow-up ratio, and 190–210°C melt temperature. The tube is collapsed, gusseted, slit, and wound on jumbo reels for conversion into stretch hoods. The compound formulation uses 100 phr LHB 118/21 AF with 1–3 wt% tackifier masterbatch and 0.5–1.5 wt% polyethylene wax processing aid; slip agents are omitted because slip reduces the cling force required for load stability. Compliance is verified through ISO 527-3 for tensile properties and ASTM D4649 for stretch film evaluation, with REACH registration applicable to the compound. At pre-stretch ratios above 150%, local thinning at corner creases initiates stress-whitening and tear propagation; process limits are set so that gauge retention at the gusset corner remains above 40 µm. Finished stretch hood articles include stretch hoods for palletized appliances, beverage bottles, insulation batts, and chemical drums.

When Greenhouse Films Are Exposed to Sulfur Burner Fumigation

Greenhouse cover film extrusion from LHB 118/21 AF is performed on three-layer blown film lines with 2.0–2.4 mm die gap, 2.5:1–3.0:1 blow-up ratio, and tower height 8–10 m; total film thickness is 150–200 µm. The formulation ratio is 100 phr LHB 118/21 AF with 0.6–1.5 wt% NOR-HALS masterbatch, 0.3–0.8 wt% UVA masterbatch, 0.5–1.2 wt% anti-drip masterbatch, and up to 15 wt% recycled LLDPE. Sulfur burner fumigation imposes an additive-selection boundary: repeated exposure to sulfur vapor above 1,500 ppm can deactivate tertiary HALS chemistries; NOR-HALS types are therefore specified after 3–5 fumigation cycles, based on stabilizer supplier technical bulletins. Compliance is assessed under EN 13206:2017 for agricultural films and REACH; thickness uniformity is checked per ISO 4593, and tensile properties per ISO 527-3. The final agricultural film articles are greenhouse covers, high-tunnel films, low-tunnel films, and shade-house cladding.

Concrete slab vapor retarder film from LHB 118/21 AF is extruded at 0.3–0.5 mm thickness with 2.0 mm die gap, 1.8:1–2.2:1 blow-up ratio, and 190–210°C melt temperature. Compounding for vapor retarder sheet uses 100 phr LHB 118/21 AF with 2–4 wt% carbon black masterbatch for UV stabilization, 0.5–1.0 wt% processing aid, and 10–20 wt% post-industrial regrind. Compliance follows ASTM E1745 for flexible water vapor retarders used beneath concrete slabs; Class A permeance is required at ≤0.1 perm as tested per ASTM E96 desiccant method. Finished product types include underslab vapor retarders, crawl-space liners, and temporary construction dust barriers.