Dushanzi HD5420GA is a high-density polyethylene blow moulding grade supplied with a nominal density of 0.954 g/cm³ under ISO 1183-1:2019 and a melt flow rate of 0.25 g/10 min under ISO 1133-1:2022 at 190°C/2.16 kg. Supplier technical literature reports a flexural modulus near 1,100 MPa under ISO 178:2019 and tensile elongation at break above 600% under ISO 527-2:2012. The grade belongs to the high molecular weight extrusion blow moulding segment, in which parison melt strength, pinch-off weld morphology, and environmental stress cracking resistance govern the commercial conversion window. The following downstream segments are specific to industrial packaging, automotive tanks, water treatment cabinets, and barrier container structures, not to film or pipe conversion.

What Prevents Parison Sag at 220°C During 200 L 1H2 Drum Conversion?

For a 200 L open-head drum produced on a high-speed shuttle blow moulder equipped with a 120 mm grooved-barrel extruder and a 15 kg accumulator head, the limiting conversion defect is not melt pressure but gravitational thinning of the parison before mould closure. HD5420GA is processed at a melt temperature of 190°C to 220°C; the upper limit is set by a measurable loss of parison hang time above 225°C, which produces wall-thickness deviation in the top chime and bottom corner regions. The accumulator head is operated with a die gap of 2.5 mm to 4.0 mm, and parison programming varies the gap by 20% to 35% across the drop length to keep the finished sidewall between 1.8 mm and 2.5 mm. The spiral mandrel uses 6 to 8 ports because fewer ports create visible knit lines that become impact initiation sites after drop testing. Blow air is delivered at 0.6 MPa to 0.8 MPa, and mould temperature is held at 12°C to 28°C to limit cooling time below 90 s for a 200 L body. Die swell factors of 1.25:1 to 1.35:1 are compensated by tooling diameter to maintain parison weight. The pinch-off weld is the critical mechanical zone; after deflashing, a flash thickness of 0.3 mm to 0.6 mm is the accepted range because thicker flash retains stress concentrations that reduce drop-impact performance under ISO 2248:2018. For lubricant and solvent packaging, the formulation is limited to neat HD5420GA, with a UV stabilizer masterbatch at 2.0 wt% to 2.5 wt% only when drums are stored outdoors, and carbon black masterbatch at 1.5 wt% to 2.0 wt% where UV exposure exceeds six months. Zinc stearate at 0.05 wt% is allowable as an acid scavenger; levels above 0.1 wt% are associated with lower environmental stress crack resistance in field trials. Pre-drying is unnecessary when pellet moisture is below 0.05 wt%; at silo relative humidity above 80%, surface condensation can cause splay defects and must be removed by dry-air purging at 60°C for 1 h. Compliance for dangerous goods packaging is established under the UN Manual of Tests and Criteria, ISO 2234:2018 stack-load testing, and ISO 2248:2018 drop testing. Food-contact use requires end-use migration testing under FDA 21 CFR 177.1520(c) and, where applicable, EU Regulation (EU) No 10/2011. End products include 200 L lubricant drums, 120 L open-head powder containers, and 220 L IBC inner bottles for water-based emulsions.

The following homologation test matrix applies to a 200 L tight-head or open-head drum converted from HD5420GA; conditions are adjusted to the declared packaging group.

On a 15-tonne extrusion blow moulder producing 20 L crop-protection jerricans for aromatic solvent concentrates, HD5420GA is selected for handle pinch-off strength and surface fluorination response rather than for neat monolayer permeation resistance. The base wall is formulated with 2.0 wt% to 2.5 wt% light-stable UV absorber/hindered amine masterbatch, and 5 wt% to 10 wt% in-plant regrind is incorporated only after screening below 1.0 mm to avoid gel defects in the handle pinch. Melt temperature is held at 190°C to 205°C, and the parison drop time is 3.5 s to 4.5 s before clamp closure. Parison programming increases wall thickness at the handle zone by 30% to prevent pinch-off thinning. Online fluorination uses 0.1% to 0.2% fluorine in nitrogen introduced into the blow gas for 1.0 min to 2.0 min, producing a 10 nm to 20 nm fluorinated boundary that is widely reported to reduce xylene permeation by one to two orders of magnitude relative to untreated HDPE while leaving the bulk tensile yield strength at 26 MPa to 29 MPa under ISO 527-2:2012. The fluorination gas oxygen content is maintained below 0.1% to prevent exothermic surface degradation. The jerrican is homologated as UN 3H1 for Packing Group II liquids, requiring leakproofness at 20 kPa and hydraulic pressure at 100 kPa for 30 min. Pesticide containers in the United States must also satisfy 40 CFR Part 165 container design and residue removal requirements. The finished articles are 20 L crop-protection jerricans and 10 L solvent-based adhesive containers.

Diesel Tank Pinch-Off Weld Morphology and Cold Impact

Monolayer diesel tanks in the 60 L to 120 L range for off-highway equipment and generator sets are extrusion-blow-moulded from HD5420GA because the ESCR failure time under ASTM D1693-21 at 50°C in 100% Igepal CO-630 is specified above 600 h. The mould must be designed with a pinch-off insert angle of 45° to 60° and a land length of 0.5 mm to 1.0 mm; a sharper insert produces a V-notch that fails under multi-axial impact at -40°C according to ISO 6603-2:2023, while a thicker land leaves amorphous material that can develop slow crack growth after 500 h of diesel exposure. Melt temperature is controlled at 200°C to 215°C, and the mould temperature is maintained at 8°C to 15°C for rapid solidification. Post-mould cooling fixtures hold the tank at 25°C to 35°C for 30 min to prevent warpage of the filler neck and mounting bosses. Wall thickness distribution scanning after moulding rejects tanks with more than 10% wall thinning in the bottom corners. The formulation uses 2.0 wt% to 2.5 wt% carbon black masterbatch for outdoor UV stability, and no stearamide slip additive is used because low-molecular-weight amide layers at the pinch-off interface reduce weld strength. For diesel tanks installed on non-road mobile machinery, permeation control is evaluated under 40 CFR 1060.103, and material-level fuel resistance is confirmed by volume swell testing according to ASTM D543. End products include 60 L to 120 L diesel tanks and 80 L urea/SCR tanks.

When 30% Post-Consumer Recyclate Is Introduced into Industrial Container Walls

Closed-loop regrind from 200 L drums and 20 L jerricans is blended with virgin HD5420GA at 15 wt% to 30 wt% only on twin-screw compounding lines with an L/D ratio of 44:1 and a melt filter of 100 µm to 150 µm. The recycled fraction shifts the melt flow rate upward by approximately 0.05 g/10 min per 10 wt% addition and narrows the upper melt-temperature tolerance by 5°C to 8°C, so accumulator-head conversion is restricted to 190°C to 205°C to avoid flash thinning at the pinch-off. Twin-screw compounding uses a temperature profile of 180°C/200°C/210°C/215°C/215°C/210°C across the six zones. Melt filter pressure differential is monitored; a rise above 0.8 MPa triggers screen change. The blend is acceptable for non-food industrial packaging when tensile yield strength remains above 24 MPa under ISO 527-2:2012 and notched Charpy impact at 23°C remains above 20 kJ/m² under ISO 179-1:2023. Recycled content in food-contact packaging is not automatically permitted under FDA 21 CFR 177.1520; a separate suitability determination under 21 CFR 170.39 is required, including source-control documentation and migration testing with food simulants. Published comparative data for this specific HD5420GA/PCR configuration above 30 wt% addition is limited, so full end-use validation is required before commercial release. End products include 25 L to 60 L industrial tote shells, 120 L open-top waste containers, and 50 L water heater expansion vessels.

For a 100 L brine cabinet used in residential water softening, the wall must combine creep resistance under continuous 0.5 MPa internal hydrostatic pressure at 60°C with compliance to NSF/ANSI 44. HD5420GA is blown into a two-part cabinet mould with a wall thickness of 2.0 mm to 2.5 mm and a pinch-off flash thickness below 0.5 mm. The accumulator head is run at 185°C to 195°C to prevent surface flow lines that appear above 200°C when the melt front passes the cabinet ribs. The parison is programmed to increase thickness by 25% at the bottom corner to avoid thin-out at the sump area. The mould has core sections below 10°C at deep draw areas to prevent blow-outs. After trimming, the HDPE cabinet is assembled with injection-moulded polypropylene lids and elastomer seals. The formulation contains 1.5 wt% titanium dioxide masterbatch for opacity and no impact modifier, because the base grade provides Izod impact above 25 kJ/m² at 23°C under ISO 180:2019. For potable-water contact, extraction testing follows EU Regulation (EU) No 10/2011 with an overall migration limit of 10 mg/dm² and FDA 21 CFR 177.1520(c) subject to end-use hot-fill testing. The grade is not recommended for continuous hot-water pressure service above 60°C because the creep modulus declines rapidly beyond that threshold. End products include 100 L water softener brine cabinets, 40 L reverse osmosis accumulator tanks, and 60 L filter housing liners.

Multi-Layer Packaging Structures with HD5420GA as Regrind Carrier Layer

Sheet coextrusion and 3D blow moulding lines use HD5420GA in the regrind carrier layer of three-layer barrier containers for aggressive solvents and oxygen-sensitive liquids. The A-layer is an ethylene-vinyl alcohol copolymer with 6 mol% to 8 mol% ethylene content to retain barrier at 80% relative humidity; the B-layer is a maleic anhydride-modified polyethylene tie resin at 2 wt% to 3 wt%; and the C-layer is a 30 wt% to 50 wt% blend of HD5420GA regrind and virgin HD5420GA. The HDPE layer is processed at 200°C to 210°C with a melt pressure of 18 MPa to 22 MPa at the die, and the layer distribution is held at 10% barrier, 5% tie, and 85% HDPE regrind by volumetric pumps. The finished containers target oxygen transmission below 0.5 cm³/(m²·day·atm) at 23°C and 50% relative humidity under ASTM D3985-17. A minimum HDPE layer thickness of 0.8 mm is required at the handle pinch to avoid delamination after a 1.2 m drop test under ISO 2248:2018. Adhesive layer thickness is held at 5% of total wall; below 3%, delamination appears after 50 thermal cycles from -20°C to 60°C. End products include 5 L agrochemical barrier bottles, 10 L solvent-based ink containers, and 20 L oxygen-sensitive adhesive containers.