LyondellBasell HDPE 5331H is processed on accumulator-head continuous-shuttle extrusion blow molding lines for rigid intermediate bulk chemical packaging. The compliance set for UN 1H2 packagings includes UN Model Regulations Chapter 6.1 drop, hydraulic internal pressure, and stack testing as referenced in ADR/RID/IMDG periodic type approvals; resin-specific food-contact status under FDA 21 CFR 177.1520 and EU Regulation (EU) No 10/2011 with migration testing per EN 1186-1 applies only where direct food contact is validated in the final monolayer structure. In virgin-regrind formulations, 100 parts of HDPE 5331H are combined with 15 to 20 parts of clean, dry, non-contaminated post-industrial trim regrind, 2.0 to 2.5 parts of carbon black masterbatch, and 1.5 to 2.0 parts of hindered amine light stabilizer masterbatch; reclaimed material above 25 parts by weight is avoided because melt fracture onset at die exit shifts upward and parison sag becomes difficult to control within the mold open time. Extrusion is conducted through a 24:1 L/D barrier screw with a grooved feed section, melt temperature 190 to 215 °C, die head temperature 180 to 200 °C, and parison programmer gap from 2.5 to 3.5 mm; blow pressure is 0.8 to 1.2 MPa, mold temperature 8 to 20 °C, and blow-up ratio 2.0 to 2.8:1. Terminal articles are 10 to 60 L rectangular and cylindrical jerrycans with UN 1H2 certification, used for liquid detergents, agrochemical concentrates, and corrosive cleaning chemicals with closure torque retention exceeding 2.0 N·m after conditioning at 40 °C for 48 h.

When high-stalk bubble stability determines blown film output on helical-grooved extruders

Blown film lines running HDPE 5331H for industrial liners and heavy-duty packaging require high-stalk bubble configuration because the resin’s melt strength counteracts extension thinning at frost line heights of 5 to 8 die diameters. Material conformity is evaluated under FDA 21 CFR 177.1520, EU Regulation (EU) No 10/2011, and when exported to North American food packaging, the specific end-use condition of use under 21 CFR 176.170(c) may be required; mechanical film characterisation follows ASTM D882 for tensile and elongation, ASTM D1709 for dart drop, and ASTM D1922 for Elmendorf tear. A typical outer-layer formulation comprises 100 parts HDPE 5331H, 20 to 30 parts C8-LLDPE with density 0.918 to 0.920 g/cm³ to reduce machine-direction tear, 2 to 5 parts high-slip masterbatch, and 1 to 3 parts antiblock masterbatch; blending below 20 phr LLDPE may produce unstable bubble edges, while above 30 phr the dart drop impact gain is offset by reduced film stiffness. Processing on a 30:1 L/D extruder at melt temperature 190 to 220 °C, die gap 1.2 to 2.0 mm, blow-up ratio 3.0 to 4.0:1, and internal bubble cooling air temperature 15 to 25 °C produces film thickness 12 to 120 µm. Terminal types include refuse sacks, construction vapour barriers, and hazardous-waste liners where tear propagation resistance is the limiting specification.

Corrugated polyolefin drainage pipe and conduit manufactured from HDPE 5331H is formed on vacuum-corrugation machines with a segmented mold tunnel, where the resin’s slow strain rate response must satisfy ring stiffness and creep ratio requirements in buried gravity-flow applications. Compliance frameworks include EN 13476-1:2018 for non-pressure underground drainage and sewerage, ASTM F2306 for corrugated HDPE pipe, ISO 9969 for ring stiffness, and ASTM D3350 for polyethylene pipe materials code classification; UV-stabilised compound formulations for outdoor storage require 2.0 to 2.5 wt% carbon black masterbatch to achieve dispersion above the minimum level in ISO 4427 or comparable outdoor exposure requirements. The compound is fed as 100 parts HDPE 5331H with 2.0 to 2.5 parts carbon black and 0.3 to 0.8 parts antioxidant masterbatch; regrind from trimmings is restricted to 10 to 15 wt% because higher fractions increase melt flow instability and inside-surface roughness. Extrusion uses a 30:1 L/D single-stage screw with melt temperature 200 to 230 °C, die temperature 180 to 210 °C, corrugator vacuum 0.06 to 0.09 MPa, and cooling water inlet 15 to 30 °C; output per line width is typically limited by vacuum mold release. Terminal products are 50 to 600 mm external diameter double-wall corrugated land drainage pipes and cable conduits for civil engineering. Data for HDPE 5331H in buried pressure pipe under PE100 MRS classification is limited; suitability must be explicitly validated against ISO 9080 long-term hydrostatic strength before pressure service.

What separates stable silicone-chilled sheet extrusion from thermoforming-induced thinning in HDPE 5331H?

Thermoformed dunnage and technical trays produced from HDPE 5331H begin on a flat-die sheet line where melt temperature, roll gap, and line speed determine forming window thickness uniformity. Material compliance for non-food industrial applications is evaluated under REACH substance restrictions and, when exported, RoHS Directive 2011/65/EU; for food-contact trays the substance migration provisions of EU Regulation (EU) No 10/2011 and FDA 21 CFR 177.1520 apply. The material formulation includes 100 parts HDPE 5331H, 20 to 40 parts closed-loop regrind from trim skeleton, 2 to 4 parts color masterbatch, and 1 to 2 parts antistatic masterbatch; regrind above 40 parts produces sheet edge curl and non-uniform sag in the heater tunnel. Sheet extrusion is run with a 30:1 L/D extruder, flexible-lip die gap 2.0 to 6.0 mm, three-roll stack temperatures 70 to 95 °C, and line speed adjusted for sheet thickness 0.5 to 6.0 mm. Thermoforming uses plug-assisted molds, sheet surface temperature 145 to 160 °C, forming pressure 0.4 to 0.7 MPa, and mold temperature 5 to 15 °C. Terminal products are reusable pallet covers, automotive interior panel blanks, and material-handling dunnage trays with dimensional recovery below 2 % after 30 cycles at 60 °C.

Flat-Die Geomembrane Stress Crack Resistance and Oxidative Induction Times

Exposed geomembrane applications evaluate HDPE 5331H against stress crack resistance, carbon black dispersion, and oxidative induction time because failure in service is driven by slow crack growth under constant tensile load. The applicable material specification is usually GRI-GM13 for HDPE geomembranes, with oxidative induction time tested to ASTM D3895, single-point notched constant tensile load to ASTM D5397, tensile properties to ASTM D638, and density to ASTM D1505; regulatory liner certifications may additionally require ISO 9001 batch traceability. The geomembrane compound is produced with 100 parts HDPE 5331H, 2.0 to 3.0 parts carbon black masterbatch, and 0.5 to 1.0 parts antioxidant masterbatch; carbon black concentration below 2.0 wt% leads to low ultraviolet ageing resistance, while above 3.0 wt% compromises melt flow and surface finish. Flat-die extrusion at melt temperature 200 to 230 °C, die temperature 180 to 210 °C, and polished chill rolls at 70 to 100 °C produces sheet thickness 1.0, 1.5, 2.0, and 2.5 mm with beta-gauge thickness control. Terminal products include landfill capping, pond liners, and mining heap leach pad barriers. Published data for HDPE 5331H under long-term ASTM D5397 in this specific geomembrane configuration is limited; qualification must be completed on the production line before specification commitment.