Korea Petrochemical (KPIC) HDPE F600 is a high molecular weight high-density polyethylene film grade with a nominal melt flow rate of 0.05 g/10 min at 190°C/2.16 kg according to ASTM D1238 and a density near 0.954 g/cm³ according to ISO 1183-1:2019. The resin is used in blown film extrusion where high-stalk bubble geometry is required to develop machine-direction orientation and downgauged film stiffness without sacrificing dart impact. In thin-gauge T-shirt carrier bag production, the grade is processed on a high-stalk blown film line with barrel zone temperatures between 160°C and 200°C. The extruder is configured with a barrier screw, L/D ratio of 30:1–33:1, and a Maddock mixing section to disperse the small gel fraction typical of high-viscosity HDPE. The die gap is set at 1.4–1.8 mm. The blow-up ratio is held between 3.0:1 and 4.5:1. Stalk height is maintained at 6–9 die diameters. Melt temperature at the die exit is kept between 195°C and 210°C. The bubble is cooled with a dual-lip air ring plus internal bubble cooling; gauge variation on a 25–35 µm web is controlled to within ±5% when the haul-off speed and screw speed are closed-loop linked.

For thin-gauge carrier film, the base resin is blended with 10–20 wt% C8-LLDPE to improve dart impact and tear strength. Slip and antiblock masterbatch is added at 0.5–1.5 wt% in a PE carrier. A white or colored masterbatch is dosed at 2–5 wt% depending on pigment strength; titanium dioxide concentrate is usually supplied at 40–60 wt% TiO₂ in the masterbatch carrier. If post-industrial reclaim is used, the addition rate is limited to 10–20 wt% because gel formation from reprocessed high molecular weight HDPE reduces bubble stability and increases pinhole incidence. Process limitations are coupled to the high melt viscosity of F600: blow-up ratios above 4.5:1 produce bubble flutter, while die gaps below 1.2 mm raise melt fracture risk. Converter control plans include ASTM D1709-16A dart impact, ASTM D882 tensile properties, and ASTM D1238 melt flow rate checks. Compliance for carrier bags is verified under the EU Packaging and Packaging Waste Directive 94/62/EC Annex II for heavy metal concentration and under REACH (EC) No 1907/2006 for SVHC content. The resulting film is converted into perforated T-shirt bags, produce bag tubes, and small waste bin liners.

What Limits Dart Impact Retention in Heavy-Duty Refuse Sack Film at 70 µm?

Heavy-duty refuse sack extrusion uses F600 as the major phase because the high molecular weight of the resin translates into melt strength that supports thick-gauge bubble stability without excessive sag. At a finished thickness of 70–120 µm, the die gap is widened to 1.8–2.2 mm. The blow-up ratio is set between 2.5:1 and 3.5:1. Frost line height is raised to 8–10 die diameters. Melt temperature is maintained at 200°C–215°C to balance melt strength against extrusion pressure. The high melt viscosity of F600 requires a high-torque extruder drive. Barrel zone temperatures are set with a slightly reverse profile to limit shear heating in the compression zone. Melt pressure stability at the screen changer should be held within ±1.0% to prevent gauge banding. On production-scale lines, screens at 60/80/100 mesh are used when reclaim is present, and screen pack change intervals shorten as the reclaim ratio increases.

The formulation is based on 80–90 wt% F600. A carbon black masterbatch is added at 3–6 wt%. The carbon black concentrate is compounded in an LLDPE carrier at 40–50 wt% carbon black. LLDPE is added separately at 5–15 wt% to recover downgauged tear strength. A recycled-content stream from post-industrial film edge trim is introduced at 10–20 wt% when the reclaim is melt-filtered through 60/80/100 mesh screen packs. Excessive reclaim creates gel counts that reduce the dart impact value by more than 15% in production-scale samples; converter control data should be generated to set plant-specific upper limits. The main process conflict is that gauge reduction below 70 µm lowers the available mass for impact absorption. The high molecular weight of F600 helps retain impact but raises back pressure, so screw speed and haul-off speed must be balanced to avoid melt temperature excursions above 215°C. Acid-scavenger stearates above 0.1 wt% are avoided because die-lip plate-out becomes visible after extended runs.

Quality gates for this application include ASTM D1709-16A dart impact, ISO 527-3 tensile modulus and elongation, ISO 1183-1:2019 density, and EN 13592:2017 for refuse sacks. Bag drop resistance is evaluated under ISO 7965-2. End products include municipal refuse sacks, construction debris bags, and medical waste liners where secondary packaging is required. The table below summarises the regulatory and test matrix applied to this application.

Three-layer coextruded food packaging webs use Korea Petrochemical HDPE F600 as the stiff core layer. In a 60–80 wt% core configuration, F600 is extruded on a core extruder with a barrier screw and a melt filtration pack. Skin layers are usually LDPE or C8-LLDPE containing slip and antiblock. The layer split is controlled to ±2% of total thickness. Typical total thickness ranges from 40 µm to 90 µm. The core layer provides the web with tensile modulus and dead-fold characteristics that are measurably higher than a monolayer LDPE film of equivalent gauge. A die gap of 1.2–1.6 mm is used. The blow-up ratio is set between 2.8:1 and 4.0:1. Melt temperature at the die is held at 190°C–210°C.

Food-contact compliance for structures containing F600 requires converter validation under FDA 21 CFR 177.1520 for olefin polymers. The regulation permits HDPE as a component of food-contact articles when the finished article meets extraction limits and use conditions in 21 CFR 177.1520(c) 2.1 and 2.2. For EU markets, the finished three-layer structure is assessed under EU 10/2011. Overall migration must not exceed 10 mg/dm² for food simulants specified in Annex III. Specific migration data for F600 in the converter’s finished structure should be generated because organoleptic transfer is influenced by core layer coverage and skin-layer thickness. The process limitation is that F600 core coverage below 60 wt% reduces the stiffness benefit, while core coverage above 80 wt% can reduce interlayer adhesion if the skins are excessively thin. End products include cereal liners, cracker pouches, dry mix pouches, and bakery bag applications requiring high web rigidity.

When High-Speed FFS Sack Lines Demand Seal Integrity After Downgauging

Form-fill-seal sack lines running at 1,200–2,000 sacks/hour impose different requirements on F600 film than simple bag conversion. The resin’s high molecular weight gives film stiffness and creep resistance, but it also raises heat-seal initiation temperature. Monolayer FFS film is therefore compounded from 70–80 wt% F600 and 20–30 wt% C6-LLDPE or metallocene LLDPE. The LLDPE component reduces seal initiation and improves hot-tack performance over a seal bar temperature range of 145°C–170°C. Dwell times on rotary seal bars are held at 0.5–1.2 s. Seal pressure is set between 1.0 N/mm² and 3.0 N/mm² depending on jaw design. The film is produced at 70–120 µm thickness using a die gap of 1.6–2.0 mm and a blow-up ratio of 2.8:1–3.5:1. Internal bubble cooling is required for throughput above 180 kg/h per die.

The main process conflict is that increasing LLDPE content lowers stiffness. A formulation at 30 wt% LLDPE can reduce ISO 527-3 tensile modulus by more than 10% compared with the F600-rich base. The converter must balance seal strength against dimensional stability. Slip masterbatch is added at 1.0–2.5 wt% to control coefficient of friction below 0.35 measured under ASTM D1894. Antistatic masterbatch is used only where dust-controlled filling is required. Seal strength is tested under ASTM F88/F88M. Hot tack is measured under ASTM F1921. Quality gates include ISO 7965-2 drop tests on filled sacks, ASTM D882 tensile properties, and ASTM D1709 dart impact. End products include valve sacks, pillow sacks, and gusseted sacks for resin pellets, petrochemical granular products, and agricultural inputs.

Drum Liner Extrusion and ESCR Boundaries

Because F600 retains a high molecular weight architecture, drum liner extrusion uses the grade where Environmental Stress Cracking Resistance is a purchase specification. The liner is blown as a thick tubular web from 80 µm to 160 µm. The die gap is set at 2.0–2.5 mm. The blow-up ratio is constrained between 2.0:1 and 3.0:1. Lower BUR values are preferred to reduce transverse-direction orientation and to maintain hoop strength. Melt temperature is kept at 200°C–215°C. Extruder back pressure is higher than with LDPE liner grades. A die with pressure rating of 50 MPa minimum is recommended for long production runs. The bubble configuration uses a low-stalk or pocket bubble rather than a high-stalk because the finished liner must retain thickness uniformity at high gauge.

Carbon black concentrate is added at 2–4 wt% for UV resistance. A UV stabilizer package based on HALS is added at 0.2–0.6 wt% where the liner is used for outdoor storage or transport. Anti-static concentrate is used at 0.5–1.5 wt% only when the packed material requires static decay protection. F600 is used as the 90–100 wt% base resin. LLDPE may be added at 5–10 wt% to improve foldability at subzero temperatures, but this blend reduces ESCR and chemical resistance. The operational boundary is set by ASTM D1693 Condition B ESCR testing. Published data for F600 under the exact exposure medium is limited, so converter-specific data must be generated because cooling rate and melt temperature change crystalline morphology and stress-crack response. For chemical contact applications, the finished liner is evaluated for mass change and tensile retention after exposure to the intended fill substance. End products include collapsible liners for drums, intermediate bulk container liners, and protective tubular liners placed inside corrugated boxes.