Thin-walled dairy and deli pots produced from LyondellBasell HDPE L5045 rely on the 45 g/10 min melt flow rate at 190 °C/2.16 kg under ISO 1133-1:2022 to fill side walls of 0.40–0.50 mm without exceeding the injection pressure limit of a 250-tonne electric toggle press. The density of the homopolymer is 0.954 g/cm³ under ISO 1183-1:2019, and the flexural modulus is near 1,240 MPa under ISO 178:2019, which supplies top-load rigidity in shallow tubs. The grade is dry-blended with a white food-contact masterbatch at 2–3 wt% through a gravimetric blender; let-downs above 4 wt% generate pigment streaks because the high-flow narrow molecular weight distribution provides limited dispersive mixing in a 24:1 L/D general-purpose screw. Melt temperature is held at 195–220 °C, mould temperature at 12–20 °C, and screw back pressure below 1.0 MPa to prevent frictional heat from driving stock temperature above 230 °C. The hold-pressure profile uses an initial pack at 55–65 MPa hydraulic pressure for 0.8 s followed by a reduced pack at 35–45 MPa for 1.0–1.5 s; this sequence prevents gate blush at a 0.6 mm valve-gate land while still compensating shrinkage. Mould venting on the cavity perimeter is cut to 0.020 mm depth to remove air from the centre core without allowing flash on a stack mould with 16+16 cavities. Food-contact compliance is established under FDA 21 CFR 177.1520(c)2.1 and under EU Regulation 10/2011 overall migration limit 10 mg/dm² with the assigned food simulant selected by the final dairy product category. Terminal articles are snap-on lid tubs for sour cream, cottage cheese, soft margarine, and portion-service condiment cups. Hot-fill above 70 °C is outside practical operating limits because the deflection temperature under load approaches the Vicat softening range of the homopolymer.

Why does hold-pressure switchover control the lidding flange more than melt temperature?

In cold drink cups and flat lids, L5045 is processed at 200–215 °C melt temperature and 10–18 °C mould temperature. The controlling process variable is the switchover from velocity control to pressure control at 95–98% of screw cushion volume. If switchover occurs after the flange freezes, the core remains un-packed and the part warps after the lid is separated from the runner system. A ring gate of 0.9–1.2 mm land depth is specified; a land below 0.8 mm freezes before filling is complete and produces flow hesitation at the flange circumference. An internal release masterbatch is added at 0.5–1.0 wt%; higher loadings reduce print adhesion on the sidewall, and surface wetting tension is checked at 38–42 mN/m following ISO 8296:2003. Cooling time is set so ejection surface temperature is below 45 °C; demoulding above 55 °C creates flange buckle when cups are stacked on high-speed packaging lines. Terminal articles include stadium cups of 300–500 cm³ capacity and flat cold-beverage lids with a 0.35 mm tamper-evident tab. Compliance for aqueous and fatty beverage contact uses FDA 21 CFR 177.1520 and EU Regulation 10/2011; carbonated beverage closures remain outside the supplied application envelope until closure tether retention and stress-crack resistance are validated on the production tool.

Pail wall thickness reduction trials in 5 L open-top containers for water-based coatings

Moulders running L5045 in small open-head pails for water-based coatings add a calcium carbonate masterbatch at 5–15 wt% to reduce cycle time and increase side-wall stiffness at a nominal wall of 1.6 mm. The filler addition lowers tensile yield under ISO 527-2:2012 by 10–15%, so the handle is gated with a fan gate of 1.5 mm depth and the weld-line strength at the core pin is specified to reach at least 80% of the non-welded tensile yield. Melt temperature is kept at 190–210 °C; higher melt temperatures with filler masterbatch can produce a 5–8% variation in hot-runner manifold viscosity. Core and cavity cooling are set differentially at 10 °C and 25 °C to shift shrinkage away from the visible outer wall. Demoulding before the side wall reaches 35 °C causes the handle to tear at the mould pin. A lid gasket groove depth of 1.0–1.3 mm compresses an EVA foam gasket to 30–40% of its free thickness. Containers for water-based latex primers, adhesives, and non-aggressive detergent concentrates are not automatically qualified for dangerous goods; full performance testing under UN 6.1.5 is required if the pail is to carry UN-classified filling materials. Exposure to aromatic solvents at 23 °C is a known stress-cracking risk for this homopolymer class, and a compatibility screen under ISO 175:2010 is required before solvent-borne filling is considered.

Storage totes, tool trays and drawer organisers are a shallow application zone for L5045; the controlling material input is not melt flow but long-term flexural creep of the unreinforced homopolymer under top loading at 40 °C. The grade is run unfilled, and regrind is held below 15 wt% because higher addition levels produce flow lines on low-gloss side walls. Published data for this specific configuration is limited, so component validation follows ISO 899-2:2003 with a maximum continuous edgewise compressive stress of 4 MPa at 23 °C for non-load-bearing dividers.

When alcohol-free cosmetic jars are switched from PETG to high-flow HDPE

Injection-moulded cosmetic jars and dispensing overcaps in alcohol-free formulations use L5045 at melt temperatures of 200–220 °C and mould temperatures of 10–20 °C. The essential process selection is a valve-gated hot runner with tip orifices of 0.6–0.9 mm; smaller tips create shear heating above 230 °C, which produces gate stringing and occasional black specks after 4–6 h of continuous running. A slip/antiblock masterbatch is added at 1–2 wt% where the jar requires automated label sleeves; surface coefficient of friction is measured following ISO 8295:1995 on plaques moulded from the same melt, and label-sleeve insertion jams occur if the value remains above 0.30. Chemical compatibility is the binding constraint. Published grade-specific solubility data for L5045 is limited, but homologous high-flow HDPE data show a sharp decline in environmental stress crack resistance above 20% ethanol and 5% isopropyl alcohol; producers therefore screen filled jars under ISO 175:2010 and ASTM D1693 with the exact emulsion before release. Migration is controlled under EU Regulation 10/2011 and cosmetics GMP under ISO 22716:2007. Terminal articles are alcohol-free cream jars, loose-powder bodies, and dispensing overcaps. Hot filling above 60 °C is not permissible because the distortion temperature of the resin is too close to the fill temperature.

At -18 °C, weld-line placement overrides notched Izod data in frozen meal tray release criteria

At -18 °C, frozen meal trays moulded from L5045 fail primarily at compartment weld lines rather than through uniform side-wall yielding. The gate is placed in the floor of each compartment at 20–30 mm from the flange; additional gates are added only when the distance between weld lines exceeds 25 mm, because every added gate creates a cold flow boundary that can fracture at freezer temperature. Melt temperature is run at 215–230 °C to improve weld strength, while total residence time above 230 °C is limited to 6 min to limit molecular weight loss. Regrind up to 20 wt% is allowed if the flake is ground to 5–8 mm and melt-filtered through a 60-mesh screen pack before dry blending; higher regrind raises melt flow by 5–10% and shifts the hold-pressure window. Filled-tray drop testing follows ASTM D2463-15 procedure B from 1.0 m at -18 °C, with failure defined as any side-wall crack visible after 24 h at freezer temperature. Notched Izod under ISO 180:2019 at 23 °C is not a release criterion because it does not capture flange sharp corners and compartment weld lines. Compliance is checked under FDA 21 CFR 177.1520 and EU Regulation 10/2011. Terminal articles are multi-compartment frozen meal trays and single-serve freezer containers. If wall thickness falls below 0.8 mm, the pack time is extended by 0.3–0.5 s; otherwise flange distortion after freezing exceeds 1.5% of the diameter.