LyondellBasell HDPE H6017 is supplied as an injection-moulding-grade high-density polyethylene in pellet form. When tested under ISO 1133-1:2022 at 190 °C and 2.16 kg, the material yields a nominal melt flow rate of 17 g/10 min; density is specified at 0.960 g/cm³ under ISO 1183-1:2019. The combination of a relatively high melt flow rate and a high density places the resin in a high-rigidity, fast-cycle segment of polyethylene moulding materials. The grade is used in rigid packaging, crates, pails, housewares, caps, closures, and small technical parts in which dimensional accuracy and short cooling time are weighted more heavily than low-temperature impact or long-term environmental stress crack resistance.

Because the 0.960 g/cm³ density increases crystalline fraction, tensile modulus and surface hardness are higher than those of medium-density and linear low-density polyethylenes at comparable molecular weight. The trade-off is a reduction in slow crack growth resistance and impact at sub-zero temperatures. Designers should evaluate those limits under ISO 179 or ISO 180 rather than transferring data from lower-density or lower-crystallinity grades. The density value also indicates that crystalline content is likely in the range of 72–78 %, estimated against a theoretical polyethylene heat of fusion of 293 J/g; peak melting temperature is typically near 132–136 °C by ISO 11357-3.

Representative values above are not sales specification limits. They are determined on injection-moulded specimens conditioned at 23 °C and 50 % relative humidity under ISO 291. Mechanical values are sensitive to mould temperature, cooling rate, and specimen preparation. A mould temperature at the low end of the recommended range can reduce surface crystallinity and lower tensile yield stress by 2–5 %; a mould temperature above 40 °C can increase cycle time without a commensurate gain in impact. Lot-specific certificates of analysis take precedence over published typical data.

What Processing Boundaries Define High-Flow HDPE Injection Moulding?

Processing H6017 is bounded by a melt-temperature window of 200–250 °C at the nozzle, with a recommended mould-temperature band of 10–40 °C. If the melt is held above 280 °C for more than a few minutes, chain scission and oxidation can produce yellowing, odour, and loss of molecular weight. Barrel residence time should therefore be kept below 5 min at the upper end of the melt-temperature range. Pre-drying is not required for normal dry-pellet storage; surface condensation after bulk storage can be removed by a 2 h desiccant-drying step at 80 °C. A general-purpose screw with a compression ratio of 2.0:1 to 3.0:1 and an L/D ratio of 20:1 to 25:1 is adequate for plastication.

On a hydraulic machine with clamp force capability above 100 t, thin-wall pails with a flow-length-to-wall-thickness ratio of 200:1 can generally be filled at injection speeds of 150–250 mm/s without exceeding melt-pressure limits of 140 MPa. The high melt flow rate reduces screw torque relative to lower-flow HDPE, but the fast cooling associated with high crystallinity shortens the processing window. Gate freeze-off occurs more quickly than in lower-density polyethylenes. Hot-runner manifolds should be sized for shear rates below 100,000 s⁻¹ to avoid flow instability, surface defects, and localised molecular weight reduction at the gate.

Because the 0.960 g/cm³ density leads to high crystallinity, mould shrinkage along flow and transverse directions is not isotropic. Published data for this specific configuration is limited, but typical HDPE mould shrinkage ranges from 1.5 % to 3.0 % under ISO 294-4. On rectangular crates, differential in-flow and cross-flow shrinkage can generate corner warpage if cooling is uneven. Tooling should maintain uniform water circuits with a temperature differential of less than 5 °C across the core and cavity. Packing pressure should be maintained at 30–60 % of peak injection pressure for a duration set by gate freeze time; insufficient packing produces sink marks on ribs and bosses.

Regrind from sprues and runners can be incorporated at levels up to 20 wt% in short-service commodity applications, but repeated heat histories reduce notched impact and increase melt flow rate. After multiple regrind generations, melt flow rate can increase by more than 10 % relative to virgin resin depending on residence time and temperature. Converters should monitor melt flow rate after each regrind generation and limit regrind in critical stress-crack or low-temperature applications. Compounding with carbon black masterbatch at 2 wt% for UV stabilisation can raise melt pressure by 3–8 % depending on masterbatch carrier and let-down ratio; gravimetric blending with a tolerance of ±0.1 wt% is recommended.

When H6017 Replaces a Lower-Flow HDPE in an Existing Production Mould

Substitution of H6017 into a tool originally cut for a fractional-melt HDPE reduces the pressure required to fill a given part, but it also changes the failure profile. Lower melt viscosity permits wall-thickness reduction to 1.0–1.2 mm in closures and housewares; however, the high crystallinity of the 0.960 g/cm³ density raises modulus and reduces dart impact at sub-zero temperatures. In drop-weight tests conducted under ISO 6603-2, H6017 exhibits a ductile-to-brittle transition at a higher temperature than a lower-density or lower-MFR resin. Published data for this specific grade is limited, so validation at the intended service temperature is required before tool conversion.

Hot-runner pressure balance changes with the lower viscosity. If the tool uses a naturally balanced runner, the pressure difference across cavities can exceed 5 % unless flow lengths or gate sizes are adjusted. Small gates of 0.8 mm may freeze before packing is complete, producing sink marks on ribs and bosses. Short-shot studies should be used to confirm gate freeze time and to set the switch-over point from velocity control to pressure control. If filling is too fast, jetting and flow marks can appear on the part surface; reducing injection speed to 100–180 mm/s or increasing gate size usually corrects the defect.

Typical application data for H6017 include crates, pails, caps, closures, and thin-wall housewares. For crate applications, stacking strength is often evaluated under ISO 12048 or ASTM D642; H6017 delivers higher top-load stiffness than high-flow LDPE because of the higher flexural modulus. For pail lids, tear-off torque and hinge life depend on notched impact and elongation; tests such as ISO 527-3 and ISO 179 are more relevant than tensile stress at yield alone. Caps and closures require removal torque and environmental stress crack resistance in contact with fats, oils, or detergents. The high density of H6017 provides lower creep than LDPE but lower slow crack growth resistance than medium-density grades.

Regulatory status is not a fixed property of the neat resin. The grade can be supplied with formulations that meet food-contact requirements under FDA 21 CFR 177.1520 or Commission Regulation (EU) No 10/2011, depending on lot-specific additives and contact conditions. Certification must be obtained from the supplier for each application and each intended food type.

Comparative Stiffness, Impact, and Environmental Stress Crack Resistance

Compared with a lower-flow HDPE of similar density, H6017 has a higher melt flow rate and therefore shorter fill time at comparable wall thickness. The cost is a reduction in molecular weight and lower notched Izod impact. Designers should not assume the same slow crack growth resistance as an extrusion-grade HDPE with a melt flow rate below 1 g/10 min. Environmental stress crack resistance measured under ASTM D1693 is generally lower in high-crystallinity grades. Published data for H6017 under 100 % Igepal CO-630 is limited; for detergent packaging, wetting-agent exposure, or hot oily environments, a medium-density polyethylene or a lower-MFR high-density grade should be assessed.

Compared with high-flow LDPE, H6017 provides higher flexural modulus, better top-load performance, and lower creep under sustained load. The trade-off is lower elongation at break and a higher ductile-to-brittle transition temperature. In cap and closure applications, the higher modulus of H6017 allows reduced wall thickness, but the lower melt elasticity can alter sealing-pressure distribution. Seal performance should be evaluated under ASTM D3078 or ASTM F88 depending on the package configuration, rather than inferred from tensile data alone.

At temperatures above 60 °C in contact with strong oxidising acids, H6017 can embrittle. At temperatures above 150 °C in hot air, oxidation of the polymer backbone becomes measurable without stabiliser protection. UV exposure degrades the surface unless carbon black or hindered-amine stabiliser package is incorporated; outdoor weatherability should be assessed under ISO 4892-2 or ASTM D2565. The resin should be purged with a compatible polyolefin such as low-flow HDPE or polypropylene; contamination with polyvinyl chloride or acetal can generate acidic decomposition products and tool corrosion. For applications requiring prolonged flexural fatigue, tensile creep under load should be measured under ISO 899-2 at the maximum service temperature.