On a 65 mm grooved-feed single-screw extruder with 30:1 L/D and a 250 mm spiral mandrel die, Lotte Chemical Titan HM5000 is processed for thin-gauge T-shirt carrier bags at a melt temperature of 199°C to 205°C, measured at the adapter. The published technical data sheet for HM5000 lists a melt flow index of 0.05 g/10 min at 190°C under 2.16 kg, a high-load melt index of 5.0 g/10 min at 190°C under 21.6 kg, and an annealed density of 0.949 g/cm³ under ISO 1183-1. The resulting melt flow ratio of approximately 100 is consistent with a broad bimodal molecular weight distribution that requires controlled shear heating in the extruder. Barrel temperatures fall from 180°C at the feed throat to 205°C at the die, with the die zone held at 205°C to 210°C. Melt pressure ahead of the screen changer typically ranges from 320 bar to 420 bar with a clean 80 mesh breaker plate. A barrier screw with Maddock mixing is preferred because the low melt index generates high shear heating in compression sections and solids-bed melting is incomplete when screw speed is raised too rapidly.

The die gap is set at 1.6 mm to 1.8 mm. A narrower gap below 1.2 mm is avoided because elevated shear stress in the spiral mandrel lands produces melt fracture on the inner bubble surface. High-stalk configuration is used with a stalk height of 600 mm to 900 mm above the die, a blow-up ratio of 3.5:1 to 5.0:1, and an internal bubble cooling differential of 1.5 mbar to 2.5 mbar. Film thickness is controlled at 8 µm to 18 µm within ±5% per ISO 4593 using a non-contacting capacitance gauge. At 12 µm, tensile strength at break under ISO 527-3 is typically 45 MPa to 55 MPa in the machine direction and 35 MPa to 45 MPa in the transverse direction. Elongation at break exceeds 350% in both directions at the same gauge. Dart drop impact under ISO 7765-1 method A for 12 µm film is 250 g to 400 g, depending on frost line height and anti-block concentration. Pre-drying is generally not required; if pellets are stored in unheated silos under surface condensation conditions, pre-drying at 80°C for 2 h eliminates surface moisture that otherwise forms gels and bubbles.

Bag conversion on a rotary or shuttle sealing machine uses heat seal jaw temperature of 130°C to 145°C, seal pressure of 0.4 MPa to 0.6 MPa, and dwell time of 0.5 s to 0.8 s. Under EU Packaging and Packaging Waste Directive 94/62/EC, the combined heavy-metal concentration in the packaging material must not exceed 100 mg/kg; a lot-specific certificate is required for export. The all-polyolefin bag is compatible with PE recycling streams after removal of print and adhesives; recycled content claims are verified under EN 15343.

What limits tear propagation and odour transfer in down-gauged produce bags?

In produce bag applications below 10 µm, the primary failure modes are puncture at stem-end protrusions and machine-direction tear propagation. HM5000 is blended with 10 wt% to 30 wt% of a C6 linear low-density polyethylene having a melt index of 0.9 g/10 min to 1.2 g/10 min under ISO 1133-1. The blend raises transverse-direction tear resistance and reduces the risk of split propagation along the machine direction. The blend is fed to a 50 mm extruder with 28:1 L/D and a 200 mm die at a melt temperature of 196°C to 201°C. Die gap is set at 1.4 mm to 1.6 mm, stalk height at 500 mm to 700 mm, and blow-up ratio at 3.0:1 to 4.0:1.

Anti-block and slip additives are added through a 5% siliceous masterbatch at a letdown of 2.0 wt% to 4.0 wt%, resulting in 0.1 wt% to 0.2 wt% synthetic silica and 0.05 wt% to 0.10 wt% erucamide. Coefficient of friction under ASTM D1894 is maintained at 0.15 to 0.30; below 0.15 roll blocking occurs, and above 0.30 bag opening becomes difficult on automated packing lines. Corona treatment raises surface energy to 38 mN/m to 42 mN/m; untreated film falls below 30 mN/m within 24 h. Haze under ASTM D1003 at 10 µm is 20% to 35%, which is acceptable for produce packaging. Seal strength measured by ASTM F1921 at 0.4 MPa sealing pressure and 0.5 s dwell reaches 2 N/25 mm to 4 N/25 mm at 120°C to 140°C.

For direct food contact, the final film must meet EU 10/2011 overall migration limit of 10 mg/dm² under the assigned food simulant for dry produce and 21 CFR 177.1520 for olefin polymers. Odour and taste are assessed under ASTM E1870; any taint score above 2.0 on the 0-to-3 scale triggers rejection. Slip additive migration into food simulants is measured by the method specified in EU 10/2011 Annex III; erucamide is permitted only within the specific migration limit assigned to it. A lot-specific certificate of conformity is required because additive masterbatch changes can shift organoleptic performance.

Thick industrial can liners are extruded at 25 µm to 40 µm on a 75 mm grooved-barrel extruder with 30:1 L/D and a 350 mm die. Melt temperature is held at 185°C to 195°C, lower than thin-film extrusion, to minimize oxidative degradation over extended runs. Die gap is 1.8 mm to 2.0 mm, blow-up ratio is 2.5:1 to 3.5:1, and frost line height is 300 mm to 500 mm. The lower stalk reduces machine-direction orientation and raises dart impact and puncture resistance. At 30 µm, dart drop impact under ISO 7765-1 method B is 800 g to 1200 g. Tear resistance measured by ASTM D1922 is 1.5 N to 2.5 N in the machine direction and 3.0 N to 5.0 N in the transverse direction. Carbon black masterbatch is added at 3 wt% to 5 wt% for outdoor storage and UV resistance; carbon black dispersion is assessed under ISO 18553.

Post-industrial edge trim is introduced at up to 20 wt%. Regrind particle size is screened to 4 mm and melt filtration uses an 80 mesh screen pack. Higher regrind levels increase gel counts and reduce dart impact by approximately 10% to 20%, so the regrind ratio is maintained below 20 wt% for liners that must pass EN 13592:2017. Heavy-duty sack sealing uses a bottom seal temperature of 140°C to 150°C, pressure of 0.5 MPa to 0.7 MPa, and dwell time of 0.8 s to 1.2 s. A 30 µm liner with a folded bottom seal and gusseted layflat withstands a filled load of 10 kg when no sharp internal objects are present. For chemical packaging, compatibility with the intended chemical and permeation behaviour must be verified by an independent laboratory because HM5000 is not an ultra-high barrier material.

Dry food liner compliance under 21 CFR 177.1520 and EU 10/2011

HM5000 can be used as a direct food-contact layer for dry foods when the resin lot and additive package are cleared for that use. Under 21 CFR 177.1520, olefin polymers are eligible for food contact subject to end-use temperature and food-type limitations; the relevant supplier letter should state compliance with 21 CFR 177.1520(c). Under EU 10/2011, overall migration into dry food simulant E for long-term storage must not exceed 10 mg/dm² when tested for 10 days at 40°C. The film is commonly blown at 15 µm to 25 µm for cereal liners, dry soup pouches, and bulk dry food inserts. A 70/30 HM5000/LDPE blend is preferred where low seal initiation temperature is required; the LDPE component lowers seal initiation to 115°C to 125°C at 0.4 MPa and 0.5 s dwell under ASTM F1921.

Organoleptic testing under ASTM E1870 is performed on the finished liner after slitting and winding. Water vapour transmission rate at 20 µm is 6 g/m²/day to 10 g/m²/day under 38°C and 90% RH per ASTM F1249. This WVTR is sufficient for moisture-stable dry foods but not for oxygen- or aroma-sensitive products; HM5000 is not a barrier layer. A coextruded three-layer structure may place HM5000 in the core at 30 wt% to 50 wt% with LDPE skins to retain stiffness and control heat sealing. If the layer is printed, surface energy should be maintained at 38 mN/m to 42 mN/m. Any lot-specific additive change requires repeated migration testing because slip and anti-block masterbatches can alter overall migration values.

When HM5000 is coextruded as a stiffness layer in laminated packaging

When HM5000 is coextruded as a core or sub-layer in multi-layer flexible packaging, its 1% secant modulus under ISO 527-3 is typically 550 MPa to 750 MPa. The stiffness contribution allows the laminate to be down-gauged without loss of flexural modulus. In a three-layer A/B/A blown-film structure, HM5000 is placed in the core at 40 wt% to 60 wt%, with LLDPE or LDPE skins. Melt streams are matched at 195°C to 200°C to prevent viscosity mismatch at the interface; die gap is 1.8 mm to 2.0 mm, blow-up ratio is 2.5:1 to 3.5:1, and frost line height is 400 mm to 600 mm. Because HM5000 has a low melt index, the core-layer extruder requires a melt pump if the die has long flow paths and melt pressure exceeds 500 bar.

The blown film is corona-treated to 38 mN/m to 42 mN/m and laminated to oriented polypropylene or polyester using a solventless polyurethane adhesive at a coat weight of 1.8 g/m² to 2.5 g/m². Lamination nipping temperature is 40°C to 60°C. After 24 h cure, bond strength measured by ASTM F904 is 3 N/15 mm to 6 N/15 mm; published data for this specific HM5000 configuration is limited, so incoming web testing is required. Final laminates are used for stand-up pouches, bag-in-box films, and block-bottom packaging where stiffness and downgauging are required. Compliance of the final laminate is assessed under EU 10/2011 when food contact is intended; the adhesive must have its own migration clearance and the total migration test is performed on the finished laminate, not on the individual layers.