PCC (Iran) HDPE HD5200B is a high-molecular-weight, broad-molecular-weight-distribution high-density polyethylene grade supplied through Petrochemical Commercial Company’s Iranian product stream for extrusion blow moulding of industrial containers, jerry cans, and technical hollow parts. The model designation HD5200B carries the HD high-density marker, the grade number 5200, and the B suffix indicating blow-moulding utility. The material is controlled to a melt index of 0.30 g/10 min under 190 °C and 2.16 kg load according to ISO 1133-1:2022, with a nominal density of 0.952 g/cm³ according to ISO 1183-1:2019. The low melt index gives the parison sufficient hang time for large-part extrusion without excessive sag, while the density provides top-load stiffness in finished containers. Pellet bulk density is approximately 0.54–0.58 g/cm³; shipment condition is natural/off-white resin without an external slip package, permitting masterbatch addition without destabilizing the process additive system.

What are the key rheological and thermal boundary conditions for extrusion blow moulding of HD5200B?

The recommended die-exit melt temperature is 190–210 °C. Below 180 °C, the high-molecular-weight fraction raises head pressure and can produce weld-line defects at the pinch-off; above 230 °C, parison sag accelerates and the phenolic-phosphite stabiliser package is consumed faster. On accumulator-head blow moulders with 10–30 L shot capacity and clamp force of 2,000–4,000 kN, typical die gap settings range from 1.5 mm to 3.5 mm. Parison programmers commonly vary wall thickness from 4 mm at the neck to 2 mm at the tail to counteract sag and maintain pinch-off integrity. Continuous-type machines with grooved feed sections and screw L/D ratios between 24:1 and 30:1 operate at screw speeds of 40–70 min⁻¹ and head pressures of 200–350 bar. Published data for this specific configuration is limited; the stated conditions are representative of industrial practice for 0.30 g/10 min HDPE blow-moulding grades and should be verified against the producer’s certificate of analysis.

The tensile and environmental stress crack profile separates HD5200B from low-molecular-weight injection grades. Tensile stress at yield is 26 MPa and tensile strain at break is commonly 600–800 % when tested under ISO 527-2:2012. Flexural modulus is 950–1,050 MPa by ISO 178:2019. Environmental stress crack resistance, measured by ASTM D1693-21 condition B in 100 % Igepal CO-630, remains above 1,000 h for typical compression-moulded specimens; injection-moulding HDPE grades with melt indices above 8 g/10 min often fail below 100 h under the same test. The Vicat softening temperature is approximately 124 °C by ISO 306:2022 method A50, and the crystalline melting peak is near 132 °C by differential scanning calorimetry at 10 K/min. Practical hot-fill service should remain below 60 °C for continuous stacked storage because creep modulus declines and vacuum paneling can occur under side-load or cooling-induced internal pressure loss. Notched Izod impact strength at 23 °C is generally 10–15 kJ/m² by ISO 180:2019, but blow-moulded part impact response is geometry-dependent and cannot be predicted from plaque values alone.

Values are typical and not specification limits.

Differential scanning calorimetry of HD5200B shows a crystallization exotherm near 114 °C and a broad melting endotherm extending from 125 °C to 135 °C, consistent with a bimodal comonomer distribution and a broad tie-molecule population. The high-molecular-weight fraction contributes to slow crack growth resistance by increasing tie-molecule density; reducing the density to 0.949 g/cm³ would improve ESCR but would lower top-load stiffness by approximately 5–8 %. Conversely, increasing density to 0.955 g/cm³ would raise flexural modulus but would shorten ESCR. The nominal 0.952 g/cm³ density is therefore a property-balance point for large blow-moulded containers, not merely a classification convenience. Short-chain branch content is not specified for every campaign, but production control of the high-molecular-weight fraction is inferred from ESCR and rheological lot-release testing.

Substitution of HD5200B for steel, fibreboard, or high-flow HDPE changes the property priorities.

Compared with high-flow injection HDPE having melt indices of 8–20 g/10 min, HD5200B generates significantly higher low-shear viscosity, preventing short-shot in thick-wall parts but eliminating thin-wall injection moulding as a practical process. Against steel, the HDPE grade reduces container mass and withstands mineral-acid and alkali contact, but it provides negligible barrier to non-polar solvents; toluene, xylene, and halogenated solvents permeate the wall and can produce environmental stress cracking at moulded-in stress concentrations. Against pipe-grade HDPE classified as PE80 or PE100 under ISO 9080:2022 and ISO 12162:2009, HD5200B has no assigned minimum required strength and is not intended for pressure-bearing pipe service. The distinction is not solely melt index: pipe grades carry hydrostatic design stress, creep rupture, and rapid crack propagation test data, whereas HD5200B is released against blow-moulding-specific parameters such as parison melt strength, die swell, and regrind compatibility. Converters replacing a 0.40 g/10 min blow-moulding HDPE with HD5200B should expect cycle-time increases of 5–10 % due to higher molecular weight, offset by reduced parison sag and higher top-load retention in tall containers.

The additive package of HD5200B is configured for extrusion blow moulding. It typically contains a hindered phenolic primary antioxidant, a phosphite secondary antioxidant, and a calcium stearate acid scavenger. Pipe-grade HDPE compounds may contain a larger carbon black loading or a bimodal antioxidant package tailored to 50-year hydrostatic service, whereas HD5200B is stabilized for repeated short-cycle thermal exposure at 190–210 °C. Film grades often contain slip and antiblock additives, which are absent from HD5200B to avoid interference with regrind processing and surface adhesion of labels or adhesive liners. The absence of a slip package means coefficient of friction on blow-moulded surfaces may be higher; converters using automatic filling lines should evaluate closure torque and sidewall stacking friction rather than assume parity with HDPE packaging grades that contain erucamide or oleamide.

When high-humidity storage or reactive masterbatch contact occurs during conversion

Although HD5200B is not hygroscopic in the pellet bulk, surface condensation on cold pellets stored below plant dew point can introduce water into the feed throat. If ambient relative humidity exceeds 70 % or pellets are transferred from an unheated silo into a warm production building, pre-drying at 80 °C for 2 h in a desiccant or hot-air hopper dryer prevents die-lip melt fracture and weld-line porosity. The grade should not be processed above 240 °C when halogenated flame-retardant masterbatches are present; liberated hydrogen halides can deactivate the hindered phenolic stabiliser and cause chain scission. Outdoor storage is limited to 12 months below 50 °C with UV-protective packaging; prolonged ultraviolet exposure reduces ESCR and promotes gel formation at the die head. For food-contact containers, the resin is produced under a formulation that can meet FDA 21 CFR 177.1520 and EU Regulation (EU) 10/2011, but the converter must verify migration limits for the intended simulant and temperature. Compliance with REACH is substance-specific and must be confirmed through the importer’s safety data sheet; no universal REACH statement applies to every HD5200B production campaign.

On single-station extrusion blow moulders equipped with 80 mm barrier screws and 30:1 L/D ratios, HD5200B typically reaches a head pressure of 280 bar at 60 kg/h throughput and 195 °C melt temperature. Regrind from trimmed top and tail flash is reintroduced at 20–30 wt%; each regrind pass can raise melt index by 0.02–0.05 g/10 min and reduce die swell by 2–4 %. Lot-to-lot variation in melt index of ±0.05 g/10 min alters parison hang time sufficiently to require parison programmer adjustment, but the sensitivity is lower than with 0.15 g/10 min fractional-melt pipe grades. During shut-down, the die head and accumulator should be purged with a lower-viscosity HDPE or blanketed with nitrogen to avoid thermoxidative formation of crosslinked gel particles at the die lips. In practice, the grade is used for 20–60 L jerry cans, coolant recovery bottles, agricultural chemical containers, and industrial pails where top-load strength, ESCR, and pinch-off weld integrity are required. It is not intended for aesthetic thin-wall bottles because the low melt index limits short cycle times and can produce parison curl on continuous shuttle machines without proper die centring.