Bapolene 152B is a film-grade low-density polyethylene with a nominal melt index of 1.9–2.1 g/10 min as determined by ASTM D1238-20 at 190°C under 2.16 kg, and a nominal density of 0.921–0.923 g/cm³ by ASTM D1505-18. In direct food-contact monolayer blown film, the resin is run on a 45–65 mm extruder with a 24:1–30:1 L/D barrier screw and a screen pack of 60/80/100 mesh. Melt temperature at the die is held between 160°C and 190°C, die gap is set at 0.8–1.2 mm, blow-up ratio is maintained at 2.2:1–3.0:1, and frost line height is fixed at 6–10 die diameters. Film thickness is produced from 25 µm to 75 µm for produce bags, bakery overwrap, frozen food bags, and boxed-carton overwrap. Food-contact status under FDA 21 CFR 177.1520(c)(2.2) and EU Regulation (EU) No 10/2011 Annex I requires overall migration below 10 mg/dm² in EN 1186-1 testing using food simulants A, B, and D2. Haze is measured by ASTM D1003-21 on a 40 µm specimen, tensile properties by ASTM D882-18 at 500 mm/min crosshead speed, and dart impact by ASTM D1709-22 Method A. Regrind from in-house trim can be added at up to 20 wt% only when the trim is free of printing ink, adhesives, and post-consumer contamination; exceeding this level increases visible gel counts and lowers tear resistance when tested by ASTM D1922-15.

What Changes When 152B Is Added to LLDPE-Rich Agricultural Film at 12 wt%?

At 12 wt% addition of Bapolene 152B to an 88 wt% butene-copolymer LLDPE matrix containing 2.0 wt% UV stabilizer masterbatch, bubble stability on a 70 mm single-screw extruder with internal bubble cooling and a 1.6 mm die gap reaches a stable processing window at blow-up ratios of 2.4:1–2.8:1. The long-chain branched fraction in the LDPE raises zero-shear viscosity and strain hardening at the frost line; below 10 wt% addition, the bubble oscillates laterally by more than ±5 mm on a 1.5 m layflat width, while above 20 wt% addition, dart impact measured by ASTM D1709-22 Method A falls below the minimum generally specified for 150 µm greenhouse film. Melt temperature is set at 175–195°C, die gap at 1.4–2.0 mm, and take-off speed is adjusted to maintain film thickness of 150–200 µm for greenhouse covers, 25–35 µm for silage stretch wrap, and 20–30 µm for mulch films. The masterbatch carrier must be LDPE-compatible; concentrate levels above 4.0 wt% with low-MFI carriers have caused feed-throat bridging on single-flighted screws. Compliance for agricultural film is limited to REACH Article 33 and EN 13206:2017 covering-film requirements; direct food contact is not intended. For long-life greenhouse film, hindered amine light stabilizer and benzophenone absorber packages are dosed at 1.0–2.5 wt%; unpigmented film without at least 1.0 wt% stabilizer embrittles in accelerated weathering per ISO 4892-2 before the expected service interval.

Shrink Film Recovery Forces in High-Speed Collation Bundling

Collation shrink film made from Bapolene 152B is produced in a high-blow, low-frost-line bubble with blow-up ratio of 4.0:1–5.0:1 and die gap of 1.0–1.4 mm. The high transverse orientation, frozen at a frost line height of 2–3 die diameters, is required to develop shrink ratios above 60% in the machine direction and above 20% in the transverse direction at 140°C when tested per ASTM D2732-14. Shrink tension is measured by ASTM D2838-18; recovery force at 120°C and 140°C determines how many polyethylene terephthalate bottles or aluminium cans a 45–75 µm film can hold in a 6-unit collation without loosening. In a continuous hot-air tunnel operating at 130–160°C with residence times of 6–12 seconds, the film surface must reach 110–140°C; tunnel speeds above 40 packs/min require forced air velocity in the range of 8–14 m/s. Increasing blow-up ratio above 5.0:1 improves transverse shrink but reduces bubble stability and produces seal-area splitting at the impulse seal bar, while ratios below 3.5:1 leave insufficient transverse orientation to hold a 6 × 1.5 L PET bottle pack at a 140°C tunnel set point. Finished goods include mineral water bottle multipacks, canned vegetable tray collations, and multipack overwrap for glass jars. Seal strength is tested per ASTM F88/F88M-21 on 25 mm sealed strips; values below 7 N/25 mm at 140°C crosshead temperature indicate that erucamide slip additive loading may have exceeded the intended 400–800 ppm range.

Extrusion lamination of paper, aluminium foil, and biaxially oriented polypropylene uses Bapolene 152B as a 15–25 µm tie layer. A 90 mm, 30:1 L/D single-screw extruder with a T-slot die and a chrome-plated chill roll maintained at 15–25°C is operated at a melt temperature of 300–320°C. The air gap between die exit and nip is set at 100–180 mm to allow controlled oxidation of the polyethylene surface; oxidation improves adhesion to aluminium foil and primed substrates. Peel strength is measured by ASTM F904-16 after 24 h conditioning at 23°C and 50% RH; typical lamination structures using aluminium foil target values above 250 N/m. Food-contact status must be confirmed on the finished laminate under FDA 21 CFR 177.1520 and EU Regulation (EU) No 10/2011; when the LDPE is separated from food by a functional barrier of aluminium foil, the overall migration limit of 10 mg/dm² applies to the combined structure. Finished formats include stand-up pouches, sachets, lidding film, and medical packaging. Direct coating onto unprimed polyester film below 12 µm thickness is not recommended because adhesion values fall below 80 N/m and melt-channeling occurs at line speeds above 200 m/min.

Heavy-duty industrial liner production using Bapolene 152B is concentrated at 100–200 µm film thickness on a 75 mm grooved-feed extruder with a die gap of 1.2–2.0 mm and blow-up ratio of 2.0:1–2.5:1. Melt temperature is held at 170–195°C. Mechanical tests on finished film include tensile strength at break and elongation at break by ASTM D882-18, Elmendorf tear by ASTM D1922-15, and dart impact by ASTM D1709-22; limits for 150 µm liners are set by end-use specifications rather than fixed resin data. The resin is processed into form-stable liners for FIBC outer shells, construction debris bags, oversize sacks, and chemical drum liners. UN 13H2 type approval for free-standing transport sacks requires additional validation of the finished article and is not an inherent property of the film-grade LDPE alone. When outdoor storage is expected, a carbon black masterbatch at 2.0–2.5 wt% must be incorporated; unpigmented film exposed to ultraviolet radiation for more than one season embrittles and fails puncture testing. Blending with acid-functional copolymers at levels above 15 wt% causes melt pressure fluctuation and gauge variation exceeding ±8% on 1.4 m layflat production.

Gauge Reduction in Consumer Can Liners Is Gated by Melt Fracture at the Die Lip

For 12–25 µm kitchen and janitorial can liners, Bapolene 152B is blended with 20–30 wt% LLDPE to balance dart impact and machine-direction tear. Extrusion uses a 65 mm blown-film line with internal bubble cooling, a dual-lip air ring, and die gap of 0.9–1.3 mm. Melt temperature at the die is 160–180°C, blow-up ratio is 2.0:1–2.5:1, and output is controlled below 0.8 kg/h per mm of die circumference to suppress melt fracture on a 300 mm die. Gauge variation is held below ±6% by capacitance scanning across the bubble; dart impact is tested by ASTM D1709-22 Method A, and tear by ASTM D1922-15. Melt fracture first appears as surface roughness at the die lip when die temperature drops below 170°C at high screw speeds, and it is controlled by increasing die temperature to 175–180°C or reducing output by 10–15%. Terminal products include tall kitchen bags, janitorial liners, and general refuse sacks. This application is not intended for direct food contact; compliance is limited to REACH Article 33 and heavy-metal limits in EU Packaging Directive 94/62/EC Annex II. Regrind from post-industrial can-liner trims can be incorporated up to 30 wt% without exceeding an internal gel count of 50 per 1 m²; post-consumer recyclate is not recommended below 18 µm because pinhole counts increase and affect leak tightness.