Amco Plastic Materials HDPE 080960 is a high-density polyethylene grade supplied as cylindrical pellets for injection molding, extrusion blow molding, and compression molding operations requiring elevated stiffness and moderate melt flow. The grade designation 080960 is consistent with a nominal density of 0.960 g/cm³ and a nominal melt flow index of 0.8 g/10 min determined at 190 °C under 2.16 kg load according to ISO 1133-1:2022. The polymerization route is not specified in the supplier’s consolidated public documentation; however, the grade is supplied with a standard stabilization package consisting of a primary hindered phenolic antioxidant, a secondary organophosphite processing stabilizer, and an acid scavenger. Slip and antiblock additives are not part of the standard formulation. Because the supplier does not publish a multi-lot statistical data sheet, users should establish incoming lot acceptance using density by ISO 1183-1:2019, melt flow rate by ISO 1133-1:2022, tensile yield stress by ISO 527-2:2012, notched Izod impact by ISO 180/A, and oxidative induction time by ISO 11357-6. The resin is intended for rigid crates, totes, pallets, industrial pails, caps, closures, and non-aggressive chemical containers. It differs from lower-density high-density polyethylene grades by exhibiting higher flexural modulus and top-load capacity, but lower environmental stress-crack resistance and reduced low-temperature impact toughness.

What Limits the Environmental Stress-Crack Resistance of a 0.960 g/cm³ High-Density Polyethylene?

Density is the principal structural variable controlling environmental stress-crack resistance in high-density polyethylene. At 0.960 g/cm³, the crystalline fraction typically reaches 75–85%, which increases lamellar thickness and reduces tie-molecule concentration between lamellae. Slow crack growth under mechanical load and exposure to surface-active agents such as nonylphenol ethoxylate solutions or strong acid solutions proceeds more rapidly than in a 0.952 g/cm³ hexene-copolymer high-density polyethylene. In ASTM D1693-15 bent-strip environmental stress-crack resistance testing, the product class associated with 0.960 g/cm³ density commonly shows shorter failure times than a fractional-melt blow molding grade with density 0.949–0.952 g/cm³ and melt flow index 0.25–0.40 g/10 min. Published data for this specific Amco product configuration under aggressive chemical exposure is limited. Therefore, direct substitution into detergent, surfactant, or organic solvent packaging should be validated with 30-day immersion testing per ASTM D543-20 and notched constant tensile load testing per ISO 22088-3:2008 where applicable. HDPE 080960 is most appropriate when stacking strength and dimensional stability dominate over prolonged contact with aggressive wetting agents. The trade-off relative to lower-density high-density polyethylene grades is a higher flexural modulus, typically in the range of 1,200–1,500 MPa by ISO 178:2019, but more conservative design stress is required in chemically active service.

Injection molding of HDPE 080960 does not require desiccant drying for moisture removal because high-density polyethylene is non-hygroscopic. Drying is only necessary to remove surface condensation when pellets are transferred from cold storage into a warmer processing area; a desiccant dryer set at 70–80 °C for 1–2 h with a dew point of -20 °C or lower is adequate. Barrel melt temperature should be maintained at 200–245 °C, with the front zone near the nozzle at the upper end of this range. Mold surface temperature should be controlled between 10 °C and 35 °C. A general-purpose polyolefin screw with L/D 20:1, compression ratio 2.5:1 to 3.0:1, and a free-flow check ring is suitable. Because the melt flow index is 0.8 g/10 min, injection and packing pressures are higher than those required for 1.2–2.0 g/10 min high-density polyethylene. For thin-wall containers below 1.5 mm nominal wall thickness, injection speed should be 300–500 mm/s and gate diameter should be at least 0.8 mm to limit jetting and flow hesitation. The solidification range is approximately 121–124 °C, so cooling time dominates cycle time in thick sections. Cooling circuits supplied with water at 10–15 °C and a circuit ΔT of 7–8 °C provide repeatable mold surface conditions. Clamp force demand increases by 10–20% relative to an identical part molded from a 12 g/10 min high-flow high-density polyethylene because the higher viscosity and packing pressure are required to control sink marks and dimensional variation.

Rheological Profile and Screw Configuration Requirements

The supplier does not publish a full viscosity curve for HDPE 080960 in the public documentation. Using similar 0.960 g/cm³ density, 0.8 g/10 min melt flow index high-density polyethylene grades as a process-class baseline, apparent shear viscosity at 210 °C and 100 s⁻¹ is expected to fall between 800 Pa·s and 1,200 Pa·s, decreasing to 150–300 Pa·s at 1,000 s⁻¹. These values are not a substitute for capillary rheometry on the actual lot; ISO 11443:2021 is the applicable method. The melt flow ratio, defined as the ratio of melt flow rate at 21.6 kg to that at 2.16 kg, may lie in the range of 50–90 for this product class, but published data for the exact Amco lot is limited. For extrusion blow molding, a barrier screw with L/D 24:1 and compression ratio 2.2:1 to 2.8:1 is recommended. In continuous 24 h operation, melt temperature should not exceed 220 °C because prolonged residence time combined with high shear can lead to oxidative chain scission and gel formation. The standard stabilization package is expected to provide an oxidative induction time greater than 20 min at 200 °C when tested by ISO 11357-6. The standard grade does not contain a high-performance ultraviolet stabilizer; outdoor service requires an additional UV masterbatch unless the finished part is protected by carbon black or other opaque pigments.

For extrusion blow molding of 5–25 L industrial containers, HDPE 080960 is processed at a melt temperature of 190–215 °C, die gap 1.2–2.5 mm, blow pressure 0.6–0.8 MPa, and mold temperature 8–20 °C. The 0.8 g/10 min melt flow index reduces screw amperage, melt pressure, and cycle time relative to a fractional-melt 0.35 g/10 min blow molding grade, but parison hang resistance is lower. The 0.960 g/cm³ density increases top-load stiffness in the cooled article and narrows the processing window for parison welding. On accumulator-head machines, total melt residence time should be kept below 10 min. Pre-blow delay should be increased by 2–3% relative to a 0.952 g/cm³ high-density polyethylene to prevent inner surface webbing in calibrated neck finishes. Top-load strength measured by ASTM D2659-16 is controlled by crystallinity and wall thickness; this product tends to shift top-load failure upward relative to lower-density high-density polyethylene, while low-temperature drop impact decreases. Transport packaging qualification should include instrumented impact testing at -20 °C per ISO 6603-2:2023.

Tight Mold Temperatures Control Warpage in Low-Taper Containers

Mold shrinkage of HDPE 080960 is anisotropic. Typical values are 1.5–2.5% parallel to flow and 1.0–2.0% perpendicular to flow, measured on standardized plaques per ISO 294-4:2018. For crates or trays with low draft angles, differential shrinkage can produce concave or convex warp if mold surface temperature varies by more than 5 °C across the cavity. A dual-circuit mold temperature setup with the core at 10–15 °C and the cavity at 20–25 °C shifts the neutral axis and controls flatness to within 1.0 mm per 300 mm span in many geometries. For a 600 mm crate, gates should be spaced no more than 200 mm apart to limit orientation gradients caused by long melt flow lengths. Post-mold fixturing at 40 °C for 15 min reduces residual stress and improves dimensional stability. Tools originally constructed for 0.952 g/cm³ high-density polyethylene may require steel-safe enlargement or regrind adjustments because the higher density increases shrinkage anisotropy and can tighten release dimensions.

Compared with a high-flow high-density polyethylene of melt flow index 12 g/10 min, HDPE 080960 is not suitable for very thin-wall injection molding below 0.5 mm because melt viscosity limits cavity filling. The product is better matched to wall sections of 1.5–4.0 mm in crates, pails, and pallet sleeves. Compared with a nucleated polypropylene homopolymer of comparable flexural modulus, HDPE 080960 offers lower density and better notched impact at 0 °C but lower heat deflection temperature. These differences determine selection for returnable logistics packaging, where stacking strength and cold-impact toughness are required but continuous service temperature is below 60 °C.

The user should establish incoming lot acceptance based on density, melt flow rate, tensile yield stress, notched Izod impact, and oxidative induction time. Because the public documentation for HDPE 080960 does not include multi-lot statistical process control data, a moving range chart of density and melt flow rate over 10 consecutive lots is recommended. If density exceeds 0.962 g/cm³, molded part shrinkage may increase beyond tool tolerances; if melt flow index exceeds 0.90 g/10 min, top-load, wall thickness, and blow molding parison sag may shift. These threshold values are process-control guidelines derived from typical high-density polyethylene behavior and should be adjusted to the user’s specific tooling.

When HDPE 080960 Replaces a Fractional-Melt Blow Molding Grade

Substitution of HDPE 080960 for a fractional-melt blow molding high-density polyethylene with melt flow index 0.25–0.40 g/10 min and density 0.952–0.954 g/cm³ changes both melt-phase and solid-state behavior. The higher melt flow index increases throughput and reduces extruder backpressure but shortens parison hang time. The die gap should be reduced by 10–15% to compensate for greater parison sag. Blow calibration pressure may need to be increased by 0.05–0.1 MPa to maintain container wall conformity. Top-load capacity improves as a result of higher density and crystallinity; however, low-temperature impact and environmental stress-crack resistance are reduced. This product should not be used as a drop-in substitute for food or detergent bottles designed from a high-ESCR hexene copolymer high-density polyethylene unless the application exposure is non-aggressive and the load environment is dominated by top compression. For industrial pails and crates, the substitution may reduce cycle time and allow a lower clamp force on a blow molding press because of the higher melt flow index. The product is not optimized for stretched blow molding or high-gloss thin-wall cosmetic containers; melt strength and surface replication differ from those of a 0.35 g/10 min grade.

Regulatory compliance for HDPE 080960 must be verified from product-specific supplier documentation. Food-contact grades may be assessed under FDA 21 CFR 177.1520(c) for olefin polymers and under EU Regulation 10/2011 as amended. The finished article, not the raw resin, must meet overall migration limits according to EU Regulation 10/2011 Annex V and EC 1935/2004. Heavy-metal restrictions under RoHS Directive 2011/65/EU and REACH SVHC should be confirmed by the supplier’s regulatory declaration. The standard high-density polyethylene formulation is not expected to contain phthalates, bisphenol A, or intentionally added per- and polyfluoroalkyl substances. These statements are based on typical high-density polyethylene homopolymer formulations and do not replace lot-specific compliance certification. For medical packaging, the user is responsible for ISO 10993 biocompatibility evaluation of the final device; raw resin compliance alone is insufficient.

For outdoor service in pallets or agricultural crates, HDPE 080960 requires stabilization against ultraviolet degradation. The standard package does not include a hindered amine light stabilizer, so exposure to direct sunlight will reduce molecular weight and embrittle surfaces unless the part is compounded with 2–3% of a carbon black masterbatch or an equivalent UV-stabilizer package. Accelerated weathering per ISO 4892-2 cycle A can be used to select the additive level, with a typical target of 50% retained tensile elongation after 1,500 h for short-lifetime agricultural applications. Published data for this specific Amco HDPE 080960 configuration under outdoor weathering is limited; therefore, material performance must be confirmed on finished articles.