BPE (Thailand) HDPE H5604F is a high-density polyethylene blow-film grade produced by Bangkok Polyethylene Public Co., Ltd. The resin is built on a bimodal high molecular weight architecture and is specified for thin-gauge grocery sacks, T-shirt bags, and industrial liners in which high tensile yield and adequate dart drop resistance are required. The nominal melt flow rate is 0.6 g/10 min determined at 190 °C under 2.16 kg load in accordance with ISO 1133-1:2022, and the nominal density is 0.956 g/cm³ in accordance with ISO 1183-1. The material places in the high-density range while retaining processability for blown film lines with appropriate screw and die geometry.

Representative property data from producer-published values are tabulated below. These values are not sales specifications and should be confirmed against the current certificate of analysis for the delivered lot.

The bimodal molecular weight distribution of H5604F is the controlling variable behind the combination of melt strength and stiffness. The high molecular weight fraction increases orientation-induced tie molecule formation during bubble stretching, while the low molecular weight fraction reduces shear viscosity in the die land and permits acceptable output. This architecture differentiates H5604F from monomodal film grades at similar density, which tend to exhibit either lower dart impact at equivalent gauge or higher extrusion pressure when the average molecular weight is increased.

For stiffness-driven packaging applications, the substitution of H5604F for butene-based LLDPE changes the property envelope in a measurable direction. The HDPE grade provides tensile yield strength in the range of 27–31 MPa, whereas a typical butene LLDPE film with density 0.920 g/cm³ yields in the range of 8–12 MPa under ISO 527-3. The trade-off is lower puncture and tear resistance, so H5604F is selected when lateral stiffness and low elongation under load are more important than tear propagation resistance. Published data for exact tear strength ratios on this specific configuration is limited, but the density and yield differential is well documented.

The additive package of H5604F is formulated without high loadings of slip or antiblock agents, which distinguishes it from off-the-shelf packaging grades that incorporate surface friction modifiers. The converter controls coefficient of friction through masterbatch addition, allowing cleaner recycling and lower haze in unmodified film.

What Does Melt Rheology Reveal About H5604F Processing Behavior?

In blown film extrusion, the melt temperature window for H5604F is 190–210 °C. Operation below 180 °C can leave high molecular weight fractions insufficiently plasticized, producing shark-skin melt fracture at the die lip and visible flow lines. Operation above 220 °C accelerates oxidative chain scission and gel formation, particularly in dead spots behind the screen pack and in the die lands. A melt temperature control band of ±5 °C is therefore required on production lines; larger excursions produce bubble instability and change gauge distribution.

The relatively low melt flow rate of 0.6 g/10 min translates into a zero-shear viscosity that is higher than that of a 0.8 g/10 min monomodal HDPE film resin. The practical consequence is a higher melt pressure before the screen pack. Process data from grooved-feed extruders with a 90 mm screw and 25:1 L/D indicate melt pressures of 280–350 bar at a die gap of 1.0 mm; pressure is equipment-dependent and should be confirmed on the target line. Batch-to-batch variation in pellet bulk density can shift feed-zone output by up to 5%, so feed throat temperature should be controlled at 30–50 °C to avoid bridging.

The recommended die gap for thin-gauge HDPE film made from H5604F is 0.80–1.20 mm. A die gap below 0.70 mm raises shear stress in the die land to the critical melt fracture range and is not recommended for monolayer lines without polymer processing aids. The radial die temperature profile should be held to ±2 °C across all zones to prevent local viscosity differences that become visible as gauge bands after drawing.

Extruder Screw Design, Barrel Profile, and Bubble Stability

A single-screw extruder with a grooved feed section and a barrier screw is the standard production configuration for H5604F. The recommended screw length is 25:1 to 30:1 L/D, with a compression ratio of 3.0–3.5:1 and screen-pack filtration at 40/60 mesh minimum. A barrier screw separates the solid bed from the melt film and reduces the likelihood of unmelted high molecular weight particles reaching the die. Grooved feed sections improve feed-zone pressure stability with high bulk density pellets and are preferred over smooth-bore feed for this grade.

Tube formation on a high-stalk bubble configuration is required to develop the bimodal resin’s orientation. The neck height is typically 6–8 die diameters, and the blow-up ratio is maintained between 3.0:1 and 4.5:1. In that configuration, the frost line height is set at 7–9 die diameters, though internal bubble cooling shifts the effective frost line upward and reduces residence time in the stretched melt state. A dual-lip air ring with lower-lip airflow set 10–20% above upper-lip airflow provides stable bubble diameter without excessive surface turbulence.

Failure modes on production lines running H5604F include cyclic bubble diameter fluctuation, which is most often caused by air ring pressure oscillation or inconsistent haul-off speed. Gauge bands traceable to die lip temperature differences are corrected by re-zeroing the die heater profile rather than by changing the melt temperature. Wrinkling in the collapsing frame is a sign of insufficient bubble cooling or a frost line too low, and it is addressed by raising the frost line or increasing internal bubble cooling air volume.

When gauge is reduced below 9 µm, dart impact retention becomes non-linear. At 12 µm the resin typically maintains the tabulated 130–160 g F50 dart impact, but at 8 µm the value may drop more sharply than a linear thickness correction predicts. Published data for this specific configuration is limited; converters should validate end-use performance on the target line. The tensile yield strength remains relatively stable because the density regime and orientation state dominate the response, but low-gauge failure in high-speed bag conversion is usually governed by tear propagation at heat-seal edges rather than tensile yield.

When H5604F Replaces a Unimodal HDPE Film Grade on Existing Conversion Lines

When H5604F is introduced to an existing line previously running a monomodal HDPE film grade, the first measurable change is an increase in extruder torque and melt pressure. The melt pressure upstream of the screen pack can rise by 10–20%, and the drive motor may require a higher current limit. The die gap should be widened by 0.2 mm relative to the monomodal setting to reduce shear stress. The barrel temperature profile is typically lowered by 10–15 °C in the feed and transition zones to preserve the high molecular weight fraction, while the die zones are kept at the same temperature to maintain surface finish.

The difference in bubble behavior is notable. H5604F forms a more dimensionally stable high-stalk bubble at equivalent output because the high molecular weight tail increases melt tension. That permits higher draw ratios without bubble sag, but it also increases the sensitivity of the frost line to cooling-air changes. If the line uses a low-bleed air ring optimized for a monomodal resin, the lower-lip air flow should be rebalanced before increasing output. The purging time when switching from a monomodal HDPE grade is typically 20–30 min until melt pressure and film haze stabilize, assuming no incompatible polymer contamination remains in the hopper or screw.

Recycle handling for H5604F follows standard HDPE film trim practice. Internal trim at addition rates up to 20 wt% can be re-introduced into the extruder feed when the trim is dry and free of paper labels, PP closure remnants, and EVA hot-melt. Higher addition rates reduce bubble stability because the recycled fraction has already undergone one heat history and contains branched oxidation products. Storing the resin under ambient conditions is acceptable; HDPE is not hygroscopic, but surface condensation on pellets stored below dew point can generate steam bubbles in the melt. If visible moisture is present, drying for 1–2 h at 80 °C is required before extrusion.

Compliance statements for H5604F are maintained under the following producer-published documents. End-use food-contact status must be confirmed for the specific package design because migration behavior depends on thickness, temperature, and food simulant.

Operational boundaries for H5604F derive from its high molecular weight tail and narrow melt processing window. The resin should not be blended with polypropylene, EVA, or ionomers unless the line is configured for dedicated recycling, because differences in melt viscosity and thermal stability generate gels, layer delamination in coextruded structures, and die-lip buildup. In coextrusion, the grade is placed in the core layer for stiffness-dominated structures where the surface layers provide seal initiation or optics. The processing window is narrow enough that melt temperature control below 180 °C or above 220 °C is the primary cause of conversion defects, and all process adjustments should be recorded against thermocouple readings rather than heater set points.