Iran Petrochemical HDPE 62N07 is an injection-moulding grade with melt mass-flow rate 7.0 g/10 min measured to ISO 1133-1:2022 at 190 °C/2.16 kg and density 0.962 g/cm³ measured to ISO 1183-1:2019. These two properties position the resin for rigid injection-moulded articles requiring short filling time and high top-load stiffness. It is not a film, sheet, or large blow-moulded-container grade because melt strength is lower than extrusion blow-moulding grades. Table 1 lists representative property data from producer technical literature; actual shipment values are provided on certificates of analysis and may differ.

For returnable beverage crates and logistics trays, Iran Petrochemical HDPE 62N07 is processed on toggle or two-platen injection-moulding machines with clamp force selected from 350 t to 1,600 t by assuming cavity pressure between 30 MPa and 45 MPa over the projected area. Melt temperature is maintained at 210 °C–250 °C at the nozzle; excursions beyond 260 °C are rejected because molecular weight degradation raises the melt flow rate and reduces notched impact strength. Mould surface temperature is controlled at 10 °C–30 °C with turbulent chilled water. The grade’s flow rate supports filling of ribbed sidewalls, stacking bosses, and interlocking lugs at screw forward speeds of 80 mm/s–180 mm/s on screw L/D 20:1–24:1. Flow lengths in crates exceeding 400 mm are supplied through multiple gates or sequential valve gates; weld lines are moved away from handle and stacking-load zones. Weld-line integrity is checked by dropping a loaded crate at −10 °C from 0.8 m onto a concrete slab; fracture at a weld line indicates gate freeze before pressure transmission.

Differential cooling between thick rib roots and thin webs is the dominant warpage input. Post-fill holding pressure is set between 50 MPa and 90 MPa for 2 s/mm of maximum wall thickness, then stepped to zero before screw recovery to reduce residual stress at ejector zones. Mould shrinkage assessed under ISO 294-4 is typically 1.6%–2.0% in the machine direction and 1.3%–1.8% in the transverse direction; core inserts for stacking lugs are offset accordingly. If the crate is used in cold-store logistics, ISO 180/A notched Izod at 23 °C alone is not a sufficient release criterion; coupons from the gate and furthest weld line are tested at −20 °C. The density of 0.962 g/cm³ increases top-load capacity but reduces impact absorption compared with lower-density HDPE; freezer-duty crates may require impact modification rather than neat 62N07.

Pre-drying is not required when the resin is stored in sealed bags and regrind content is below 20%. If surface moisture is present or regrind has been stored above 60% relative humidity, splay appears at the gate. Hopper drying at 80 °C for 2 h–4 h removes this defect.

Why Does 62N07 Permit Cycle-Time Reduction in High-Cavitation Cap Moulds?

Cap and closure production with HDPE 62N07 is concentrated in high-cavitation tools of 32–96 cavities, where cycle time is limited by gate freeze and ejection rather than melt delivery. Melt temperature at the barrel is set between 230 °C and 250 °C; mould cooling water is held at 8 °C–15 °C to stabilise the tamper-evident band. Injection speed is set to fill each cavity in 0.08–0.15 s, producing shear rates above 10 000 s⁻¹ at pin gates. Shear thinning at these rates permits filling of fine tamper-band perforations without flash. Holding pressure is applied at 35 MPa–60 MPa for 0.4–0.8 s, then released; overpacking causes seal-plate ovalisation. Seal-plate flatness is checked against a 0.2 mm feeler gauge on random cap samples. Gate vestige stringing occurs above 255 °C, while incomplete band filling occurs below 225 °C in thin bands; both define the operating window.

For food-contact water and dairy closures, conformity is established under EU Regulation (EU) No 10/2011 Annex II and FDA 21 CFR 177.1520; overall migration is tested under EN 1186-1 and specific migration under EN 13130-1. As a monolayer HDPE cap on carbonated soft-drink PET bottles, the resin does not provide the primary CO₂ barrier; published data for this specific configuration is limited. The density of 0.962 g/cm³ increases skirt stiffness compared with lower-density HDPE and reduces application-torque loss during storage. Cap application torque is determined by neck finish and closure design, not by the resin alone.

In thin-wall IML dairy tub and lid production, cavity wall thickness is set between 0.35 mm and 0.70 mm, and flow length/wall thickness ratio often exceeds 200:1. Accumulator-assisted injection units deliver forward speeds above 200 mm/s; holding pressure is restricted to 35 MPa–70 MPa to avoid core deflection in thin cores. Melt temperature is held at 230 °C–250 °C; the upper value compensates for the label heat sink. The mould is chilled to 8 °C–15 °C with high-turbulence water circuits. In-mould label stock is conditioned at 23 °C and 50% RH before insertion to prevent post-demoulding curl. Back pressure is set at 3 bar–10 bar, and screw recovery is timed so plasticising consumes no more than 80% of the cycle to avoid a starved feed condition. The high flow rate supports wall-stock reduction, but the high density of 0.962 g/cm³ reduces low-temperature crack resistance; filled-tub drop testing is therefore performed at 4 °C and at 23 °C, with rim cracks evaluated by puncture or edgewise impact tests where available.

Rim sealing of IML tubs against lids is governed by core/cavity concentricity and HDPE shrinkage anisotropy. The lid channel diameter is biased by 0.3 mm–0.8 mm for typical tub sizes because HDPE shrinkage of 1.6%–2.2% exceeds that of PP and changes undercut ratio. Hot-runner valve gates are preferred over cold spruce because gate stringing on thin rims disrupts lid seal. A two-stage holding profile with the second stage at 40%–60% of the first stage is used before final pressure release to avoid sink at the label edge. Compliance for dairy packaging is demonstrated under EU Regulation (EU) No 10/2011 and FDA 21 CFR 177.1520; the processor must verify that label adhesive and printing system do not raise overall migration above the applicable limit.

Open-Top Pails for Lubricants and Agrochemicals: ESCR and UN Certification Boundaries

Open-top pails of 1 L–10 L are injection moulded in single- or multi-cavity tools with melt temperature 210 °C–240 °C and mould surface temperature 10 °C–20 °C. The handle ears and spout attachment lugs are the limiting zones: they fill through restricted gates that impose high shear stress, and premature gate freeze at the ear root leads to sink and weld-line cracking. Holding pressure of 60 MPa–90 MPa is maintained for 2.5 s/mm of ear thickness, and gate diameter is kept above 1.2 mm to prevent freeze-off before pressure transmission. UN-certified packs classified as 3H1 or 3H2 are conditioned filled at −18 °C for 24 h before drop and stack tests; the pail must not leak after a drop from the height specified for packing group I, II, or III.

The combination of 7.0 g/10 min melt flow rate and 0.962 g/cm³ density gives useful top-load capacity and dimensional stability for lubricant pails, but the ESCR of high-flow HDPE is below that of high-molecular-weight blow-moulding grades. Compatibility with aggressive contents is screened under ASTM D1693 condition B; failure before 24 h in the presence of Igepal CO-630 indicates a high propensity for environmental stress cracking in service. Nonionic surfactant concentrates, aqueous ammonia above 1%, and certain ester-based lubricants can initiate cracking at the handle root when filled pails are stored above 40 °C. In these cases the ear-root radius is increased to not less than 2 mm, and hot-punch or post-mould trimming is used to remove internal stress raisers. Published data specific to 62N07 in aggressive agrochemical immersion is limited; service compatibility must be confirmed by pack testing rather than by melt flow or density values alone.

When 62N07 Replaces Polypropylene in Thin-Walled Housewares: Injection Window and Shrinkage Consequences

Where processors substitute HDPE 62N07 for high-flow polypropylene in storage boxes, hangers, and garden accessories, the process is adjusted around a different solidification range and shrinkage anisotropy. The same tool is usable only if the cavity dimensions and gating tolerate shrinkage of 1.6%–2.4% versus PP’s typical 0.8%–1.5%; ribs, bosses, and snap-fit lugs designed for PP often develop sink marks or binding in the HDPE variant. Melt temperature is reduced to 210 °C–230 °C to limit shrinkage, while mould temperature is kept at 10 °C–20 °C. The HDPE part shows lower flexural modulus than PP at room temperature, so rib height is increased by 15%–25% to compensate. Gate freeze time is longer, which permits lower holding pressure but increases total cycle time by 5%–10% compared with PP at equal wall thickness.

The density of 0.962 g/cm³ raises flexural modulus compared with lower-density HDPE, but Vicat softening point measured to ISO 306/A50 remains below PP heat-resistance levels. Snap-fit insertion and removal forces are evaluated at 23 °C and −10 °C because the HDPE variant responds differently to creep under load. Colourants and nucleating agents alter shrinkage uniformity and should be matched to the base resin lot before steel is cut. Regrind content above 30% can reduce notched impact and increase warpage; therefore regrind ratio is controlled by measured loss in notched impact under ISO 180/A rather than by melt flow drift alone.