In monolayer carrier-sack extrusion, Iran Petrochemical HDPE HF5110 is processed on a single-screw extruder with a 30:1 L/D barrier screw and a spiral mandrel die. Barrel set points from feed to metering are 180–220°C, while die temperature is maintained at 210–225°C. Die gap is held between 0.8 mm and 1.2 mm; narrowing the gap below 0.8 mm in this molecular weight range raises melt shear sufficiently to initiate surface melt fracture when die temperature falls below 205°C. Blow-up ratio is set between 3.5:1 and 5.0:1, with frost line height controlled at 6–10 die diameters using internal bubble cooling pressure of 40–120 Pa. For a 65 mm extruder producing 12 µm film on a 200–250 mm die, output is typically 120–180 kg/h at screw speed of 45–75 rpm. The grade is run neat or with slip/antiblock masterbatch at 1.5–3.0 wt%; masterbatch addition above 5 wt% reduces dart drop impact measured by ASTM D1709, and film below 10 µm in monolayer structures shows higher gauge variation unless an automatic air ring is installed. Compliance for food-contact carrier sacks is assessed under 21 CFR 177.1520 and EU Regulation No 10/2011, with overall migration limited to 10 mg/dm² or lower according to the converting declaration. Terminal products include vest carrier bags from 10–25 µm, with machine-direction tensile yield measured by ASTM D882 typically 20–28 MPa and elongation at break 400–650%.

Thin-Gauge HDPE Waste Sack Processing Window at 10–18 µm

At film gauges between 10 µm and 18 µm, Iran Petrochemical HDPE HF5110 is run against two limiting constraints: bubble stability at low gauge and melt cleanliness when post-consumer recyclate is introduced. In waste sack lines, post-consumer high-density polyethylene is added at 20–40 wt% to the extruder feed; this requires a continuous screen changer with filtration size of 100–150 µm to prevent gel defects and die lip build-up. Surface moisture carried by regrind is removed by a hopper dryer set at 70–80°C for 2–3 h when ambient relative humidity exceeds 60%. Melt temperature at the die is held at 215–225°C to reduce melt pressure, and bubble internal pressure is kept between 50–100 Pa; higher pressure destabilizes the bubble at gauges below 12 µm. Blow-up ratio is controlled at 4.0:1–5.0:1, and the frost line is lowered to 5–7 die diameters for faster cooling and reduced bubble wander. Mechanical requirements are verified with ASTM D1709 dart drop, where 15 µm waste sack film typically falls between 150–250 g, and with ASTM D5748 puncture resistance at 10–20 N. Regulatory compliance for packaging heavy metals is assessed under EU 94/62/EC, requiring the sum of lead, cadmium, mercury and hexavalent chromium not to exceed 100 ppm by weight; converters also report REACH SVHC content below 0.1 wt% per article. Terminal products include bin liners, can liners and industrial waste sacks in 10–25 µm gauge, where thickness uniformity is monitored by an online scanner with tolerance of ±5% around target.

What Restricts Draw-Down Stability in 8 µm Produce Bag Film?

The draw-down stability boundary in 8–10 µm produce bag film is governed by melt strength, die gap and cooling uniformity. For Iran Petrochemical HDPE HF5110, die gap is reduced to 0.7–0.9 mm to increase transverse orientation, but a gap below 0.7 mm raises melt shear beyond the critical range for this molecular weight distribution and causes visible melt fracture at standard output. Blow-up ratio is increased to 4.5:1–6.0:1 to improve film balance; high stalk height is maintained at 6–9 die diameters. A dual-lip air ring with internal bubble cooling at 60–120 Pa is required to stabilize the frost line, and die temperature is held at 220–230°C. Fluoropolymer processing aid is added at 400–800 ppm to delay die build-up and reduce extrusion pressure. Gel content of the feedstock is held below 100 mg/kg by melt filtration. Mechanical verification uses ASTM D1922 Elmendorf tear; on 10 µm produce bag film, machine-direction tear is typically 18–35 g/mm and transverse-direction tear is 25–45 g/mm. Food-contact suitability for uncut fresh produce is evaluated under 21 CFR 177.1520 and EU Regulation No 10/2011, with specific migration testing using food simulant A and C under 40°C/10 days conditions where applicable. Terminal products are star-sealed produce roll bags and high-speed automatic packing films, where the conversion line requires a coefficient of friction below 0.30 as measured by ASTM D1894.

Coextruded barrier structures employ Iran Petrochemical HDPE HF5110 as the moisture-barrier core or skin-layer component in three-layer and five-layer blown film lines. A representative three-layer dry-food liner uses a layer distribution of 50–65 wt% HF5110 in the core, 20–30 wt% adhesive tie resin, and 10–20 wt% barrier polymer or metallocene sealant skin; the exact ratio is adjusted to keep the HDPE core fraction above 45 wt% because lower core fractions reduce moisture barrier performance measured by ASTM E96. Extruder diameters for the HDPE layer are 65–90 mm with a 30:1 L/D barrier screw, and die set point is 215–230°C. The combining block and spiral mandrel are designed for melt viscosity differences; interfacial instability appears if the HDPE layer melt temperature is raised above 235°C or if the barrier polymer is run below its recommended melt window. Layer thickness is controlled by gravimetric feeders and validated by optical microscopy on cross-sections. Barrier test requirements for dry-food packaging call for water vapour transmission rate below 3 g/m²/day at 38°C and 90% RH. Regulatory compliance is documented under 21 CFR 177.1520 for olefin polymers, EU Regulation No 10/2011 with overall migration below 10 mg/dm², and REACH Article 33 communication where applicable. Terminal products include cereal liner bags, dry ingredient liners and high-moisture-barrier laminations that use the HDPE web as a sealing layer.

Heavy-Duty Industrial Sack Construction and Dart Impact Grading

Heavy-duty industrial sacks produced at 50–120 µm use Iran Petrochemical HDPE HF5110 at 80–100 wt% with 0–20 wt% metallocene LLDPE to recover transverse tear lost in high-density film. Blow-up ratio is deliberately lowered to 2.5:1–3.5:1 to increase machine-direction stiffness, and die gap is widened to 1.2–1.6 mm to reduce melt fracture risk at high output. Melt temperatures are set at 200–220°C; lower feed temperatures of 180°C preserve the molecular weight of the high-viscosity grade. Dart impact of 50 µm film measured by ASTM D1709 method B is typically 400–650 g, while Elmendorf tear measured by ASTM D1922 remains 20–35 g/mm in machine direction and 40–70 g/mm in transverse direction. Secant modulus is measured at 1% strain by ASTM D882 and is typically 800–1,100 MPa. For sacks intended to hold construction rubble or aggregates, puncture resistance is verified by ASTM D5748 with values in the 25–50 N range at 50 µm. Production equipment includes a 90 mm grooved-feed extruder with 30:1 L/D and a 250–350 mm spiral mandrel die with internal bubble cooling. Terminal products are rubble sacks, FIBC liners and heavy-duty industrial packaging where the film must retain dimensional stability under stack load.

When HF5110 Is Selected as the High-Stiffness Core in Stretch Hood and Lamination Films

When Iran Petrochemical HDPE HF5110 is selected as the high-stiffness core in a stretch hood or lamination film, the converter runs the core extruder at 215–235°C and designs the layer ratio so that the HF5110 core represents 30–50 wt% of the total structure, with LLDPE skins at 50–70 wt% to provide puncture resistance and seal initiation below 110°C. A five-layer line with a 250–400 mm die and collapsing frame geometry suited to high neck height is used. Blow-up ratio is set at 4.0:1–5.0:1; frost line height is maintained at 7–10 die diameters to balance transverse orientation and core stiffness. The HDPE core raises secant modulus of the total film by 150–250 MPa relative to an all-LLDPE structure, but core fractions above 55 wt% decrease stretchability and increase elastic recovery stress. Stretch hood film performance is tested for puncture force by ASTM D5748, tensile yield by ISO 527-3, and tear by ASTM D1922. Compliance for industrial wrapping is maintained under REACH and EU Regulation No 10/2011 where the film contacts packaged goods indirectly. Terminal uses include high-stiffness stretch hood webs, transfer laminating layers, and protective collation shrink films where a printable high-density layer is required.