HANWHA LLDPE 9730 is a linear low-density polyethylene resin specified for blown-film and cast-film conversion. The producer’s published nominal melt flow rate is 1.0 g/10 min at 190 °C under a 2.16 kg load ISO 1133-1:2022, and the nominal density is 0.918 g/cm³ measured by ISO 1183-1:2019. The resin belongs to the ethylene copolymer class with a linear backbone and controlled short-chain branching, which distinguishes it from high-pressure LDPE grades containing long-chain branching and from conventional butene-based LLDPE grades with broader compositional distribution. The main processing route is single-screw extrusion with grooved or smooth-bore barrels having L/D ratios of 24:1 to 30:1, and typical melt temperatures range from 185 °C to 215 °C. End uses include collation shrink film, stretch hood, lamination film, and general industrial packaging where a balance of tear resistance, seal response, and optics is required. Published data for specific high-speed production configurations is limited; the producer’s current technical bulletin remains the controlling specification for grade lot acceptance.

What Melt Extrusion Conditions Preserve Molecular Weight Distribution During 9730 Film Fabrication?

Processing above 240 °C is not recommended for extended residence times because thermal-oxidative chain scission can narrow the molecular weight distribution and reduce film impact resistance. The preferred melt temperature window for blown film is 185–215 °C, measured at the die entrance with an immersion probe. On a grooved-feed extruder with a 55 mm screw and 30:1 L/D, stable output is typically observed at screw speeds between 60–100 rpm; melt pressure before the screen pack remains below 350 bar with clean screens. Excessive shear heating from high compression ratios can generate local melt temperatures exceeding the thermal-oxidative onset, producing oxidized gel particles. The film die gap should be maintained at 1.5–2.0 mm for the 0.918 g/cm³ density class, because wider gaps increase orientation and narrow-gap operation raises shear rate and can induce sharkskin. Frost-line height is normally set between 6–10 die diameters for a 2:1 blow-up ratio; deviations above this range increase transverse-direction tear while lowering machine-direction tensile strength, as measured by ASTM D882-18.

Bubble stability is the limiting process variable on high-density air-ring lines because LLDPE has lower melt tension than high-pressure LDPE at equal melt index. Operators running the resin on a conventional low-pressure die often compensate by blending 10–20 wt% of an LDPE grade with a melt flow rate of 0.3–0.5 g/10 min; this blend increases melt strength but also raises haze by 1–3% absolute in 50 µm film when tested according to ASTM D1003-13. Film blocking force can be controlled by limiting frost-line height and using a chilled air stream at 8–12 °C, though the effect on coefficient of friction is measurable only after 24 h aging under 23 °C / 50% RH conditioning per ASTM D618-21. On tandem winder systems, residual stretch must be kept below 0.5% because thickness-band defects become visible above this threshold in 25 µm gauge.

Seal Integrity Testing Across Film Gauges Made with 9730

Heat-seal performance is evaluated on laboratory sealers with flat, heated jaws controlled to ±2 °C across the seal bar. Seal initiation temperature for HANWHA LLDPE 9730 is commonly determined using ASTM F88/F88M-21 at a dwell time of 0.5 s and a pressure of 275 kPa. The reported hot-tack window on vertical form-fill-seal equipment is constrained by the resin’s melting range, not by density alone; film with a density of 0.918 g/cm³ typically exhibits a seal strength plateau between 120–140 °C seal-bar temperature. Packaging lines converting 30 µm film should verify that the crimp jaw geometry does not reduce the seal area below 1.0 mm² per mm of seal length; otherwise, burst strength measured under ASTM F2054/F2054M-21 becomes the controlling failure mode. Because LLDPE can contain processing aids that migrate to the sealant layer, corona treatment levels must be measured before sealing when lamination is intended, using ASTM D2578-17 wetting tension.

When 9730 Is Substituted for High-Pressure LDPE in Collation Shrink or Stretch Hoods

High-pressure LDPE replacement requires evaluation of shrink tension and low-temperature puncture, not just dart impact. In collation shrink film, the lower melt tension of LLDPE reduces machine-direction shrinkage at a given blow-up ratio; processors counter this by increasing the blow-up ratio to 2.5–3.5:1 and reducing the die gap to 1.2–1.5 mm. At these settings, the film exhibits lower tear propagation resistance in the machine direction when tested by ASTM D1922-15, and the dart drop value measured with ASTM D1709-16a Method A can shift by more than 20% for a 5 °C frost-line temperature change. In stretch hood applications, the resin’s elastic recovery at 100% elongation is lower than that of high-pressure LDPE; recovery values above 80% require blending with 20–30 wt% of a high-molecular-weight LDPE. Published data for this specific configuration is limited, but industrial trials on rotary hooding machines with 12–15 pre-stretch rollers show that film thicknesses below 60 µm increase the frequency of corner punctures when the pallet load contains sharp-edged packages.

Food-contact status is determined by the finished article, not by resin grade alone. HANWHA LLDPE 9730 can be used in food-contact film when the converter demonstrates compliance with European Commission Regulation (EU) No 10/2011 and with GB 9685-2016 for the intended market. Under U.S. jurisdiction, the resin falls under 21 CFR 177.1520 when olefin polymer specifications are met; end users should obtain the producer’s food-contact declaration and verify global migration under the appropriate EU 10/2011 test conditions. The material is subject to REACH registration, and processors must review the safety data sheet for specific migration limits if processing aids are used.

Surface treatment for printing and lamination on HANWHA LLDPE 9730 must be specified as wetting tension, not as corona wattage. In line with ASTM D2578-17, a minimum wetting tension of 38 mN/m is normally required for solvent-based lamination, while water-based inks often demand 40–42 mN/m. Reversion in treated film occurs within 48 h when stored at 30 °C; therefore, slip and antiblock packages must be selected to avoid excessive migratory additives. The addition of erucamide slip reduces the coefficient of friction from 0.6 to 0.2 at 1000 ppm, but delayed blooming can continue for up to 72 h after winding. Processors using downstream solventless lamination should test for plate-out; published data for this specific configuration is limited.

Assessing Operational Boundaries in High-Shear Cast Film Lines

Cast-film conversion of HANWHA LLDPE 9730 requires attention to die-lip deposition and melt fracture at high line speeds. When line speed exceeds 250 m/min with a 0.75 mm die gap, shear rate at the lip can exceed 800 s⁻¹; this regime has produced sharkskin on laboratory cast-film lines, although published data for this specific grade is limited. A die temperature of 240 °C is sometimes required to eliminate surface roughness, but the higher temperature can increase off-gassing and reduce the molecular weight distribution through thermal chain scission. Chilled-roll temperatures set at 20–25 °C with a nip pressure of 2–4 bar control crystal nucleation and film optics. The addition of 0.05–0.10 wt% of a fluoropolymer processing aid is a standard industrial remedy; its effect on wetting tension must be verified after corona treatment because migration to the surface can reduce adhesion in extrusion lamination.

Film Blocking Force on Fresh and Aged Surfaces

Blocking force for 25 µm blown film is measured at 23 °C / 50% RH after 24 h conditioning under ASTM D3354-15. The value depends on the migrating amide slip system and on corona treatment level. Untreated film typically gives blocking below 0.3 N/mm, whereas a surface treatment above 42 mN/m can increase blocking by 50–100% because of increased surface polarity. Converters should quantify blocking before specifying antiblock masterbatch; silica antiblock at 2000 ppm reduces measured force but also lowers optics, with haze increasing by 0.5–1.5% absolute in 50 µm film per ASTM D1003-13.

Because the resin is not significantly hygroscopic, pre-drying is unnecessary for typical indoor storage below 60% RH. For outdoor or high-humidity storage above 90% RH, surface moisture can create steam streaks in film; hopper drying at 40 °C for 2 h with dry air is a practical boundary rather than a full desiccant drying cycle.