DL Chemical HDPE 5502 is a high-molecular-weight blow moulding polyethylene with a melt flow rate of 0.35 g/10 min at 190 °C under ISO 1133-1:2022 and a nominal density of 0.955 g/cm³ under ISO 1183-1:2019. The resin does not require pre-drying when stored in sealed original packaging at ambient relative humidity below 60%; if opened packaging has been exposed above that threshold, hopper drying at 80 °C for 2 h prevents surface splay. In extrusion blow moulding, melt temperature is maintained between 180 °C and 210 °C; the lower limit is set by melt homogenisation and the upper limit by parison sag, odour generation, and degradation of internal antistatic or colour masterbatch concentrates.

Extrusion blow moulding of UN-rated industrial liquid packaging

For tight-head and open-head containers used for hazardous liquids, HDPE 5502 is processed on accumulator-head shuttle blow moulding machines with screw L/D ratios of 24:1 to 30:1 and grooved feed sections. The parison is programmed at 30–40 wall-thickness points to compensate for swell variation at the handle pinch-off and bottom pinch-off zones; mould cooling water is held at 12–25 °C, and blow air pressure is set between 0.7 MPa and 1.0 MPa. Formulation addition for UN-certified jerrycans typically places HDPE 5502 at 96–98 wt% with carbon black or colour masterbatch at 1.5–2.5 wt%; total non-polymeric masterbatch loading above 3.0 wt% is avoided because pinched-weld strength degradation is measurable under -18 °C conditioning in the UN drop test. Industry compliance is anchored to the UN Model Regulations Chapter 6.1 and, for European road transport, ADR 6.1; packaging type codes 3H1 and 3H2 require hydrostatic pressure, leakproofness, stack, and drop tests for the specific filling material. Environmental stress-crack resistance is evaluated by ASTM D1693-15 in an aggressive wetting agent and on finished containers by ASTM D2561-17; test failures at handle pinch-off or side seams are the principal rejection mode in production-scale lot certification. Terminal finished products include 10 L to 60 L tight-head jerrycans, open-head pails, and narrow-neck industrial liquid containers for oxidising, corrosive, or flammable preparations.

When a three-layer cosmetic bottle places HDPE 5502 as the outer virgin layer over a post-consumer recycled core, the outer layer is specified at 20–35 wt% of total wall thickness and the strand is processed through a two-extruder coextrusion blow moulding die; the outer extruder is run at 180–200 °C melt temperature and the layer distribution is measured by near-infrared thickness scanning on the shuttle line. Formulation addition in the outer layer uses HDPE 5502 at 96–98 wt% with pearlescent, colour, or UV masterbatch at 2–4 wt%; external release agents and mineral fillers are excluded because they reduce bottle drop impact and create visible flow lines at the pinch-off. Drop impact is verified according to ASTM D2463-15. Industry compliance for cosmetic packaging follows EC No 1223/2009 for product-packaging compatibility and ISO 22715:2006 for primary packaging design and labelling; where oral-care or food-adjacent claims exist, the finished article is additionally checked against FDA 21 CFR 177.1520 and EU 10/2011 extraction conditions rather than relying solely on resin grade compliance. Production-scale failure modes include parison curl at high ambient humidity and surface fish-eye defects when regrind exceeds 15 wt%; stabilised lines therefore limit in-house regrind to 10–15 wt% and verify closure torque retention on automated capping equipment. Terminal products include 150 mL to 1 L cylindrical and oval bottles for shampoos, conditioners, body wash, and skin-care lotions.

What governs wall-thickness repeatability in extrusion-blown pharmaceutical containers?

Pharmaceutical bottles requiring tight weight and wall-thickness tolerances are moulded from HDPE 5502 as a 100% virgin stream; in-house regrind is either excluded or capped at 10 wt% when pharmacopoeial extractables and leachables are under evaluation. The process is run on continuous shuttle extrusion blow moulding machines with gravimetric feeding and closed-loop parison thickness control; clamp force for a single-cavity 250 mL bottle is typically between 80 kN and 150 kN. Melt temperature is held at 185–200 °C, die temperature is maintained within ±2 °C of setpoint, and mould coolant is controlled at 10–15 °C to prevent wall-thickness drift and sink marks. Industry compliance references USP <661.1> and <661.2> for plastic packaging system suitability, Ph. Eur. 3.1.3 for polyethylene materials with additives, and ICH Q3D for elemental impurities in the finished package. The terminal product range includes 60 mL to 500 mL OTC tablet, powder, and liquid-dose bottles with tamper-evident and child-resistant finishes; published data for DL Chemical HDPE 5502 in blow-fill-seal continuous lines is limited, and that configuration requires line-specific qualification rather than grade-level substitution.

Household cleaning fluid bottles requiring high environmental stress-crack resistance use HDPE 5502 at 95–98 wt% with colour masterbatch at 2.0–4.0 wt%; calcium carbonate and talc fillers are excluded because they reduce weld-line elongation and accelerate premature failure in bleach-containing formulations. The container is produced on continuous shuttle or wheel-type extrusion blow moulding machines with blow air at 0.6–0.9 MPa and mould temperature 12–20 °C; side seams and handle pinch-off are trimmed in line and leak-tested at 15–20 kPa differential pressure. Compliance for the packaging of hazardous household preparations follows CLP (EC) No 1272/2008 classification and, where closures are child-resistant, ISO 8317:2015 testing procedures. Terminal finished products include 500 mL to 5 L trigger-spray, squeeze-pour, and handled bottles for alkaline cleaners, dilute hypochlorite, and surfactant-based formulations.

Diesel exhaust fluid tank stock and long-term urea contact resistance

Onboard SCR tanks for AUS 32 diesel exhaust fluid are blow moulded from HDPE 5502 with carbon black masterbatch at 2.0–2.5 wt%; the resin constitutes 97.5–98.0 wt% of the formulation. No plasticiser or external lubricant is added because low-molecular-weight additives can migrate into the urea solution and affect NOx reduction catalyst performance. The process uses accumulator-head machines with 3D suction blow moulding or parison manipulation for complex underbody geometries; melt temperature is limited to 190–210 °C, and clamp force for a 30 L tank tool typically exceeds 300 tonnes. Weld-line integrity at pinch-off zones and storage stability are assessed under ISO 22241-1:2019 AUS 32 quality requirements and ISO 22241-3:2017 handling and storage provisions; filled-tank endurance and slosh fatigue are generally defined by vehicle manufacturer specifications rather than a single ISO standard. Terminal products include 10 L to 60 L on-board urea tanks and replacement reservoirs for passenger cars, commercial vehicles, and off-highway engines.

When agricultural chemical shelf life depends on permeation resistance and neck finish stability

For agricultural pesticide and adjuvant containers, HDPE 5502 is used as the primary structural resin at 96–98 wt%, with UV-stabilised or antistatic masterbatch at 2.0–4.0 wt%; fluorinated surface treatment is specified when solvent permeation must be reduced, but published data for DL Chemical HDPE 5502 in high-barrier fluorinated multi-layer agricultural containers is limited, and qualification against the actual solvent blend is required before production. Extrusion blow moulding is followed by in-line leak testing to UN Model Regulations Chapter 6.1 hydrostatic and leakproofness procedures, and neck-finish torque retention is checked after induction sealing because cap back-off under warehouse temperature cycling is the main field failure mode. Industry compliance references UN Model Regulations Chapter 6.1 for hazardous liquids, FAO/WHO packaging guidelines for pesticide containers, and ASTM D2684-12 for permeation of liquids and gases through plastic bottles. Terminal finished products include 1 L to 20 L containers for pesticides, adjuvants, and plant growth regulators.