Sinochem Quanzhou HDPE 5502 is specified as a high-molecular-weight, high-density polyethylene for continuous extrusion blow moulding, with a typical density of 0.955 g/cm³ when tested to ISO 1183-1:2019 and a melt mass-flow rate of 0.35 g/10 min at 190 °C/2.16 kg when determined by ISO 1133-1:2022. The material’s processing envelope is centred on accumulator-head and reciprocating-screw blow moulding machines with screw L/D between 24:1 and 30:1, melt temperatures from 180 °C to 220 °C, and blow-up ratios from 2:1 to 3.5:1. The application routes below are restricted to industrial segments where these rheological and mechanical properties are matched to specific container performance requirements; no claim is extended to rotational moulding, film, cast sheet, or injection moulding.

Industrial jerrycans and open-head drum liners intended for UN-certified dangerous goods are produced from 100 wt% virgin Sinochem Quanzhou HDPE 5502, with no post-consumer recyclate added unless the design type is re-qualified under Chapter 6.1 of the UN Recommendations on the Transport of Dangerous Goods, Model Regulations. The addition ratio for a PE-carrier dark blue or carbon black masterbatch is held to 1–2 wt%, and external lubricants or processing aids are excluded to preserve the low melt flow rate and high parison hang strength required for tall containers. Modal compliance is documented under ADR/RID/IMDG Code packing instruction P001 for liquid dangerous goods, and the finished container must carry the UN packaging code, material symbol, design-type approval reference, and hydrostatic test pressure marking. On the production line, accumulator-head extrusion blow moulding machines with a screw L/D of 25:1 to 30:1 are operated at a melt temperature of 190–210 °C and a die gap of 2–4 mm, with continuous parison programming to increase wall thickness at the top and bottom pinch-off zones.

The critical failure modes observed at production scale are parison sag above 220 °C, fold-over at the flash pocket when pre-blow delay is too short, and brittle cracking at the pinch-off weld after contact with aggressive surfactant or hypochlorite solutions. Wall-thickness distribution is measured at the container shoulder, sidewall, and chime; typical minimum values are 0.8–1.2 mm for 5–10 L jerrycans and 1.2–2.0 mm for 20–30 L containers. Environmental stress crack resistance is evaluated under ASTM D1693-15b, Condition B, 100% Igepal CO-630, with F50 values specified by the design type; stacking performance is verified against ISO 12048, and leak testing is conducted at 0.03 MPa internal pressure for packaging group II and 0.02 MPa for packaging group III. Terminal products include 5 L, 10 L, 20 L, 25 L, and 30 L jerrycans, in addition to open-head drum liners with a wall thickness between 1.0 mm and 2.5 mm.

What cooling and tooling changes prevent stress cracking in automotive windshield washer fluid reservoirs?

In automotive underhood fluid systems, windshield washer fluid and coolant overflow reservoirs are blow-moulded from HDPE 5502 at 100 wt% with 2–3 wt% high-load carbon black masterbatch for UV and heat resistance; clean internal regrind from the same reservoir production line is restricted to 10 wt% maximum to stabilise impact behaviour at −30 °C. The governing test framework includes ISO 6603-1 for multi-axial impact and ISO 527-1:2019 for tensile properties, while coolant compatibility is assessed by immersion in 50/50 ethylene glycol/water at 90 °C for 1,000 h. Processors should note that at regrind fractions above 10 wt%, the melt flow rate shifts upward and the parison becomes measurably more prone to sag, requiring a 5–10 °C reduction in melt temperature to restore the specified hang strength.

Production is carried out on reciprocating-screw extrusion blow moulding machines with a fitted accumulator head and a converged die geometry; the melt temperature is maintained at 195–215 °C, while the mould is cooled at 10–20 °C. A blow-up ratio of 2.0–2.6:1 and programmed parison thickness generate local wall sections of 2.0–3.5 mm, because the reservoir must withstand pressure pulses generated by windshield washer pumps and under-bonnet temperatures up to 105 °C. Terminal products include 2–5 L washer reservoirs and 1–3 L coolant overflow bottles, with leak testing at 0.05 MPa and drop impact at −20 °C defined by the vehicle platform specification.

Detergent and hypochlorite bleach bottles processed without formulation dilution

For hypochlorite-containing household and institutional formulations, HDPE 5502 is used as the sole polymer component at 100 wt% because high environmental stress crack resistance is required for contact with linear alkylbenzene sulphonate, alcohol ethoxylate, and sodium hypochlorite solutions at pH values between 10 and 13. The addition ratio for a PE-based colour masterbatch is limited to 0.5–2.0 wt%; polypropylene-based colour concentrates are excluded because they reduce weld-line elongation and increase drop-impact variability. Compliance for bleach-containing consumer containers is evaluated under ASTM D2463-15 for drop impact and the surface-active agent stability requirements of 21 CFR 178.1010 where sanitising formulations are involved.

Extrusion blow moulding is performed on long-bed extruders with a grooved feed section and screw L/D of 25:1 to 30:1, at melt temperatures between 185 °C and 205 °C. Parison programming is configured to create a minimum sidewall thickness of 0.5 mm for 500 mL trigger-bottle formats and 1.0–1.5 mm for 4 L floor-cleaning bottles, with the blow-up ratio held below 3.0:1. Terminal products include 500 mL and 1 L trigger spray bottles, 750 mL viscous-product bottles, and 4 L janitorial bleach containers with standard neck finishes.

When non-sterile pharmaceutical and personal care packaging requires ambient filling, containers blow-moulded from HDPE 5502 are limited to solid-dose tablets, capsules, effervescent tubes, topical creams, and oral care preparations. The formulation is normally 100 wt% HDPE 5502 with no intentional addition of processing aids other than a 0.5–1.5 wt% white titanium dioxide masterbatch used to achieve opacity and light protection. Compliance is evaluated under USP <661.1> for plastic packaging systems, Ph. Eur. 3.1.3 for polyolefins, and 21 CFR 177.1520(c) 3.1a/3.2a for olefin polymers intended for food and drug contact; because the additive package may vary by production campaign, the converter must request the relevant regulatory status from the resin manufacturer.

The processing route is continuous extrusion blow moulding on high-output wheel machines with multiple moulds, where melt temperature is held at 180–200 °C and mould cooling temperature is set between 6 °C and 12 °C to meet tight body diameter tolerances. Wall thickness for 30–250 mL tablet bottles is controlled at 0.6–1.0 mm, while 500 mL topical containers require 1.2–1.8 mm sidewalls to pass closure integrity testing under ASTM D4991-07(2015) for vacuum leak detection. Terminal products include cylindrical and square tablet bottles, ophthalmic and nasal wash bottles without preservative release concerns, and tube-shaped personal care containers with tamper-evident neck finishes.

When lubricant oil bottles are blow-moulded with same-family regrind

In the production of lubricant and metalworking fluid containers, HDPE 5502 is processed at 85–100 wt% virgin resin with 0–15 wt% clean internal regrind generated from the same bottle line, provided the regrind is dried and screened through a 2 mm mesh to remove gels and char particles. External post-consumer recyclate is excluded because peroxides and polar contaminants from prior packaging can reduce environmental stress crack resistance in contact with ester-based synthetic lubricants and chlorinated metalworking fluids. The governing methodology is ASTM D543-14 for chemical resistance of plastics, with tensile strength retention measured after 500 h immersion in a representative 10W-40 engine oil at 70 °C.

These bottles are blow-moulded on continuous rotary or shuttle machines with a melt temperature of 190–210 °C; when 10–15 wt% regrind is present, the melt viscosity shifts lower and the head temperature is reduced by 5–10 °C to maintain parison hang strength. The die gap is adjusted to 2.5–4.5 mm for 1 L and 4 L finished containers, and the mould is cooled at 12–18 °C; container wall thickness is programmed to 0.8–1.5 mm to resist panel deformation under top load. Terminal products include 1 L, 4 L, and 5 L motor oil bottles, gear oil and automatic transmission fluid containers, and 20 L metalworking fluid pails with UN packaging markings where required.

Agrochemical container wall integrity under UN and FAO specifications

For crop protection product formulations classified as flammable or toxic, agrochemical containers are moulded from HDPE 5502 at 98–100 wt% with 0–2 wt% UV-stabilised colourant masterbatch. The core regulatory references are the FAO/WHO Guidelines on Packaging for Pesticides and the UN Model Regulations for dangerous goods when formulated products carry a transport classification. Barrier performance for cyclohexanone, xylene, and ester-based formulation systems is addressed not by increasing the resin addition level but by post-mould fluorination to a surface fluorine-to-carbon ratio typically between 0.5:1 and 1:1 on the inner wall, as measured by X-ray photoelectron spectroscopy.

Extrusion blow moulding is run on accumulator-head machines at melt temperatures from 190 °C to 210 °C, with a blow-up ratio of 2.0–2.8:1 and programmed parison to prevent thin spots at the handle bridge and base chime. The mould cooling medium is maintained at 8–14 °C, and containers are leak-tested under 0.02–0.03 MPa internal pressure after 24 h conditioning at 23 °C. Terminal products include 0.5 L, 1 L, 5 L, and 10 L high-density polyethylene bottles with UN markings, child-resistant closures, and induction-sealed neck finishes.