LyondellBasell HDPE L5332CP is a high-density polyethylene resin supplied as a pelletized copolymer for heavy-wall blow molding, large-part extrusion, and industrial containment applications. The grade is built around a high molecular weight distribution that provides elevated melt strength and environmental stress-crack resistance while retaining sufficient output in accumulator-head equipment. Representative values from supplier technical literature include a nominal density of 0.953 g/cm³ under ISO 1183-1 and a melt flow rate of 0.30 g/10 min at 190 °C/2.16 kg under ISO 1133-1. Tensile yield stress is listed at 26 MPa according to ISO 527-2, flexural modulus at 1,050 MPa according to ISO 178, and Vicat softening temperature at 77 °C using ISO 306/A50. Supplier data further report environmental stress-crack resistance failure time of approximately 600 h under ASTM D1693 condition B at 50 °C in 10% Igepal CO-630. These values are representative and may shift with pigment concentrate, regrind ratio, or conversion conditions.

Because the resin is positioned for thick-wall containers, automotive tank shells, and industrial packaging, its low melt flow and high ESCR separate it from general-purpose high-flow HDPE grades that process more easily but fail earlier under continuous chemical or mechanical load. The absence of a PE100 pressure-pipe classification should be noted; L5332CP is not a piping compound qualified under ISO 4427 or EN 12201, and published data for long-term hydrostatic strength in pipe form are limited.

Processing Window and Rheological Boundaries for L5332CP

Extrusion blow molding of L5332CP is typically conducted with melt temperatures between 210 °C and 230 °C at the die head, using a grooved-feed single-screw extruder with barrier screw geometry and an L/D ratio of 24:1 to 30:1. The grooved feed section improves solids conveying against the elevated head pressure generated by the high molecular weight fraction. Accumulator-head equipment should maintain die temperatures within 200–220 °C and mold temperatures at 20–40 °C to control flash formation and cooling-induced warpage. Parison programming is recommended because a non-linear wall thickness profile is typically required to compensate for parison sag. The resin’s high melt strength delays thinning, but it does not eliminate sag under hang times above approximately 20 s on large shot sizes.

Thermal stability limits are defined by oxidative degradation rather than moisture-derived hydrolysis. HDPE L5332CP is not hygroscopic, and pre-drying is generally unnecessary if the pellet surface remains free of condensation. However, sustained bulk melt temperatures above 250 °C or residence times exceeding 10 min in a stagnant screw channel can initiate chain scission and crosslinking, reducing ESCR and increasing gel counts. During start-up, the barrel temperature profile should be ramped from feed section 180–200 °C to metering section 210–230 °C. In injection blow molding or large-part injection molding, mold shrink allowances of 1.5–2.5% are used, with higher values in thick sections due to slower crystallization.

Melt stability during repetitive extrusion is a further control parameter. Because L5332CP contains a high molecular weight fraction, regrind addition above 30 wt% can shift parison sag and die swell, particularly if the regrind has undergone multiple heat histories. Production-scale experience on twin-station shuttle blow molders with shot volumes from 5 L to 30 L indicates that regrind ratios above 30% may require die gap adjustment of 0.1–0.3 mm to maintain target part weight. Melt pressure at the die should be recorded; a progressive rise above 350 bar often signals crosslinked gels or degraded material from stagnant zones. Processors should avoid combination with amine-based antistatic additives unless compatibility has been verified, because amine additives can accelerate oxidative degradation during prolonged melt residence and may alter organoleptic properties in food-contact articles.

How Does L5332CP Compare With Unimodal HDPE Blow Molding Grades?

Relative to a general-purpose unimodal HDPE blow molding resin with a melt flow rate near 0.7 g/10 min, L5332CP exhibits lower flow, higher molecular weight, and substantially longer ESCR. This comparison is relevant for converters selecting between thin-wall consumer packaging and heavy-wall industrial containers. The table below summarizes representative values; specific commercial grades may deviate according to comonomer type and molecular weight distribution.

Because PE100 bimodal pipe compounds are designed for long-term hydrostatic strength, their higher density and comonomer placement differ from blow molding grades. L5332CP should not be substituted into pressure pipe applications without hydrostatic design basis validation under ISO 9080 or ASTM D2837.

In large-part blow molding, the governing mechanical responses are tensile yield stress, flexural modulus, and ESCR rather than short-term elongation at break alone. Under ISO 527-2, L5332CP retains ductile yield at moderate strain rates, but its performance in chemical environments is better characterized by ASTM D1693 testing. The resin is suitable for contact with dilute acids, alkalis, and aqueous salt solutions in industrial containment, but strong oxidizing acids, aromatic hydrocarbons, and chlorinated solvents can reduce ESCR. Processors must conduct end-use compatibility testing because environmental stress-crack attack is a function of stress, temperature, and chemical concentration rather than material resistance alone.

Regulatory compliance with European Union food-contact framework Regulation (EU) No 10/2011 or U.S. FDA 21 CFR 177.1520 is the responsibility of the converter and depends on the final article, pigment package, and processing aids. Published data for this specific configuration under all food-contact migration conditions are limited. RoHS Directive 2011/65/EU and REACH SVHC statements should be requested from the supplier for the specific lot, especially when regrind or masterbatch additions alter the final composition.

When ESCR and Impact Resistance Govern Container Wall Design

Applications such as agricultural chemical drums and automotive fuel tank shells impose simultaneous requirements for drop impact strength, ESCR, and permeation resistance. In drop impact testing per ASTM D2463, HDPE L5332CP typically exhibits ductile failures at low temperatures, but specific results depend on wall thickness, tool cooling, and the presence of weld lines. Blow molding trials on accumulator-head machines with clamp force between 800 kN and 1,200 kN for 200 L drum formats have shown that parison programming is required to maintain uniform wall distribution above 3 mm in the chime and corner regions.

For automotive fuel tank shells, HDPE L5332CP alone does not provide sufficient hydrocarbon permeation resistance to meet evaporative emission requirements under U.S. EPA test procedures. Post-molding fluorination, sulfonation, or coextrusion with a barrier layer is necessary. Without such barrier treatment, the fuel tank surface exceeds allowable hydrocarbon permeation limits on typical emission certification cycles. Processors should verify actual permeation values using gravimetric cup tests at 40 °C with reference fuel CE10 or equivalent, because supplier datasheets do not specify permeation coefficients for all fuel formulations.

Temperature limits for continuous service of unmodified HDPE containers are commonly cited near 60–65 °C for industrial liquids. Above this range, creep modulus decreases and ESCR failures accelerate under internal pressure or stacking loads. L5332CP is not formulated with sufficient UV stabilizer for long-term outdoor exposure unless a carbon black masterbatch is added during conversion; unpigmented or non-black parts should be protected from extended sunlight.