At wall sections of 0.8–1.1 mm, thin-wall injection moulding of dairy tubs, portion cups, and compatible lids from Borealis HE1878 uses the nominal density of 0.954 g/cm³ (ISO 1183-1) and melt flow rate of 7.5 g/10 min at 190 °C/2.16 kg (ISO 1133-1:2022) to balance cavity filling against rapid solidification. In direct food contact, the natural grade is processed without slip or antiblock additives; when opacity is required, an EU 10/2011-compliant white masterbatch is added at 2–4 wt%, and any processing aid must appear in the Union List of authorised substances in Commission Regulation (EU) No 10/2011 Annex I. Melt temperature is set at 220–250 °C at the nozzle, while mould temperature is held at 10–25 °C. On 8–12 cavity high-speed toggle presses, injection speeds of 200–350 mm/s are used, and hot runner manifold zones are maintained within ±5 °C of the nozzle setpoint; cavity-to-cavity part weight variance above 0.03 g in a 0.9 mm wall cup is generally traced to manifold imbalance rather than melt flow. Cycle times of 6–8 s are attainable when screw cushion is held at 3–5 mm and decompression is limited to 5–10 mm; larger decompression settings introduce splay at the gate. The finished dairy tub or lid falls under FDA 21 CFR 177.1520 for olefin polymers in repeat-use food contact and under EU 10/2011, where overall migration must not exceed 10 mg/dm² in food simulants assigned to the final article. Migration of post-added colourants and processing aids must be assessed separately because base resin compliance does not cover masterbatches. The operational limit is melt temperature above 260 °C or residence time longer than 5 min, conditions that can raise odour and taste carry-over in organoleptic panels.

What Limits Gate Freeze-Off in Sub-2.0 g Carbonated Soft Drink Closures?

Closure manufacturing from HE1878 is concentrated in 48–96 cavity hot runner tools where shot weight per closure is 1.8–2.2 g. Gate diameter is reduced to 0.4–0.7 mm for sub-gated or edge-gated designs, and transfer pressure rises to 800–1200 bar under fast injection speeds of 150–300 mm/s. Hot runner nozzle temperatures are held within ±3 °C to keep cavity-to-cavity mass deviation below 0.02 g. Melt temperature at the nozzle is set between 215 °C and 240 °C, and mould temperature is kept at 10–20 °C; dropping below 8 °C causes condensation on the mould face and increases surface defects, especially on polished vent edges. The tether hinge of tethered closures is moulded at 0.25–0.35 mm thickness, and flow-front stall before the tether tip is a known cause of intermittent hinge failure in high-speed filling lines. For torque control, converters add an erucamide-based slip masterbatch at 1–3 wt%, resulting in 800–1500 ppm erucamide in the final closure; torque behaviour is measured on 26 mm PCO 1881 neck finishes according to closure customer specifications rather than a universal polymer standard. The base resin already contains antioxidant and acid scavenger packages. Additional catalyst neutralisers are not required and may shift organoleptic performance. Compliance for beverage closures references EU 1935/2004 for food contact materials, FDA 21 CFR 177.1520 for the olefin polymer, and EU 2023/2006 good manufacturing practice. Hot-fill applications above 85 °C are outside the normal operating envelope because thread engagement can decay through thermal expansion and stress relaxation; published data for HE1878 in hot-fill closure systems is limited.

Stackable logistics crates and pallets moulded from HE1878 are processed in wall thicknesses of 2.5–4.0 mm on two-platen hydraulic injection machines with clamp forces from 800 t to 1500 t; shot weights in this segment can exceed 4.5 kg in a single cavity. Melt temperature is reduced to 200–230 °C and mould temperature is raised to 20–35 °C to preserve weld-line strength at rib intersections, because the notched Charpy impact of 4 kJ/m² at 23 °C (ISO 179-1/1eA) does not predict low-temperature impact at weld lines. The tensile modulus of 1100 MPa (ISO 527-2:2012) supplies the short-term stiffness needed for pallet racking, but creep deformation under sustained load is controlled by rib design rather than by base resin alone. For outdoor service, 2–3 wt% carbon black masterbatch is added to give total carbon black content of 1.5–2.5%, and clean internal regrind from sprues and rejected parts can be incorporated at 15–25 wt% without loss of production consistency when melt filtration is maintained. Injection speed is held at 50–120 mm/s to prevent jetting in thick sections; pack pressure is set at 50–70% of peak injection pressure for 8–12 s before cooling. Cooling time dominates cycle time, with a 3.2 mm wall crate typically running 28–38 s in a well-vented tool. Compliance for industrial crates and pallets is governed by dimensional and mechanical tests such as ISO 8611-1 for pallet performance and ISO 291 for conditioning. REACH SVHC and RoHS 2011/65/EU compliance for the base resin are available, but converters must re-evaluate after adding conductive or flame-retardant masterbatches.

Injection-Moulded Pails for Non-Food and Light Industrial Fill Goods

Pails in the 3–5 L range are injection moulded from HE1878 with side-wall thicknesses up to 2.0 mm and integral handle hinges, whereas larger tight-head drums are reserved for high molecular weight blow-moulding HDPE grades. On four- to eight-cavity tools, fill times of 1.8–2.5 s are achieved with injection pressure at 900–1100 bar; mould temperature is set between 12 °C and 20 °C, and cooling time before ejection is 10–15 s to avoid undercut distortion at the snap-on lid seat. For paints, adhesives, and lubricant fill goods, 0.5–1.5 wt% antistatic masterbatch is used to reduce surface resistivity to 10⁹–10¹¹ Ω as measured according to IEC 61340-2-3; antistatic loadings above 2 wt% are avoided because they reduce notched impact. Outdoor-stored pails use 2 wt% hindered amine light stabilizer masterbatch instead of carbon black when light colour is required. Dangerous goods packaging is not a resin property; the finished pail must pass UN model regulations drop, leakproofness, stack, and pressure tests for the specific packing group and fill. The grade is not recommended for pails holding xylene, toluene, or strong polar solvents because environmental stress cracking can initiate at gate vestiges and weld lines, particularly in parts heavier than 300 g that have not been annealed.

When Toys and Small Housewares Are Subject to EN 71-3 Migration Limits

Toy components and small housewares moulded from HE1878 require final-article compliance because metal-based colour concentrates and processing aids can introduce extractable elements that are not present in the base resin. The melt temperature is set at 210–235 °C, with dry colour or masterbatch added at 1–3 wt%; colour concentrates for toy use must be screened for lead, cadmium, chromium, mercury, arsenic, selenium, barium, antimony, and organotin so the finished article meets the extractable-element limits of EN 71-3. Injection pressure in multi-cavity tools is held at 600–900 bar, and screw back pressure is kept below 10 bar to limit shear heating of pigment particles during extended residence. Mould surfaces are polished to SPI A-2 or better to reduce micro-cracks that can trap saliva and increase extraction during simulated use. Interlocking toy blocks, storage tote boxes, and small desk accessories are typical end products; latch and hinge features require a minimum transition radius of 0.5 mm at the wall-to-base junction to limit stress concentration. Mechanical safety is assessed under EN 71-1, including drop and torque tests on assembled parts, and the base resin is supplied without intentionally added phthalate plasticizers or BPA. Converters must re-verify the finished article after adding flexible overmoulds, adhesives, or labels, because those secondary materials are not covered by the base resin declaration.

Injection-moulded diagnostic and personal care packaging produced from HE1878 covers non-implantable, short-term patient-contact components such as specimen containers, reagent reservoir caps, and cosmetic jar bases. The processing window is narrower than in industrial packaging because the completed articles may be sterilised by gamma irradiation or ethylene oxide. Melt temperature is maintained at 220–240 °C; a dedicated drying step is not required below 60% RH, but above this level a hopper dryer at 60–70 °C for 2–3 h is used to prevent splay. Masterbatch content is restricted to 0.5–2 wt% low-extractables concentrates, and silicone-based internal lubricants are avoided because they can interfere with adhesive bonding or laser marking. Gamma irradiation is generally tolerated up to 25 kGy, but published data for HE1878 under sterilisation dose mapping is limited; above 25 kGy, oxidative chain scission can reduce impact strength and accelerate embrittlement during storage. Ethylene oxide sterilisation is less damaging to HDPE but requires aeration to remove residual gas from thick bosses and closures. The final device manufacturer bears responsibility for ISO 10993-1 evaluation and ISO 10993-5 cytotoxicity testing; the base resin supplies chemical characterisation data but not biocompatibility certification. Wall thickness is normally below 1.8 mm, and the application space excludes implantables, parenteral fluid contact, and prolonged mucosal contact.