Luban LLDPE EFDA-7047 is a butene-based linear low-density polyethylene resin produced by OQ in Sohar, Oman, for thin-gauge blown film extrusion. The resin is manufactured in a gas-phase fluidised-bed polymerisation process and supplied in pellet form with a phenolic/phosphite antioxidant stabilisation package. The nominal melt flow rate is 1.0 g/10 min when measured at 190 °C/2.16 kg in accordance with ISO 1133-1:2022; the nominal density is 918 kg/m³ in accordance with ISO 1183-1:2019. The molecular architecture consists of a linear ethylene backbone with short-chain branches contributed by butene comonomer, producing a density below that of high-density polyethylene while retaining a defined crystalline melting peak. The grade is used in general-purpose packaging, heavy-duty sacks, agricultural films, lamination films, carrier bags, and frozen-food packaging. The as-supplied resin does not contain slip, antiblock, or long-term UV stabiliser additives beyond the base antioxidant package; converters add these functional additives when required by optical, frictional, or weathering specifications.

Storage and drying follow standard polyolefin practice. Pellets are pneumatically conveyed and stored in silos or bulk bags; pellet surface moisture remains below 0.05 wt% under dry warehouse conditions. If bags are stored in unheated warehouses with high relative humidity, surface condensation may develop; drying in a desiccant hopper dryer at 50–60 °C for 2–4 h is recommended when visible surface moisture is present or when moisture-sensitive printing or lamination processes demand controlled water content. Long-term storage should avoid sustained temperatures above 50 °C to limit additive migration and pellet agglomeration.

How Does EFDA-7047 Respond to Blown Film Orientation and Cooling History?

In blown film, final mechanical response is set by the interaction of melt temperature, die gap, blow-up ratio, frost-line height, and internal bubble cooling. On a conventional monolayer line with a 1.8 mm die gap, a 2.5:1 blow-up ratio, and a 40 µm film thickness, the film develops anisotropic properties: machine-direction orientation is controlled primarily by haul-off speed, while transverse orientation is set by circumferential bubble expansion. The frost-line height is typically held at 6–10 die diameters. Lowering the frost-line height increases quench-related orientation and may raise film modulus while reducing dart impact; raising it often improves impact but makes bubble stability more sensitive to ambient air movement. The following typical values are reported for a stabilised 40 µm film and are not to be interpreted as specification limits; commercial conversion requires lot-specific testing on the actual coextrusion or monolayer line.

The 120 g dart impact at 40 µm places EFDA-7047 above many broad-molecular-weight high-pressure LDPE film grades that fall below 80 g at the same gauge under identical test conditions. Elmendorf tear in the transverse direction is typically greater than in the machine direction because transverse orientation is lower at the stated blow-up ratio. Converters requiring higher machine-direction tear may reduce haul-off speed relative to melt output or increase blow-up ratio; higher transverse tear may be obtained by reducing blow-up ratio or increasing frost-line height. Haze is affected by die gap, quench rate, and spherulite size; fast quench may lower haze but can promote blocking if the film surface is below the dew point at the winder. The Vicat softening temperature is a thermal resistance indicator, not a heat-seal initiation temperature; heat-seal performance must be evaluated by hot-tack and seal-strength tests on the finished film.

Extrusion Parameters and Failure Modes on Conventional Blown-Film Lines

On monolayer lines equipped with single-screw extruders of 24:1 to 30:1 L/D, EFDA-7047 is processed at barrel temperatures of 170–200 °C and die temperatures of 180–210 °C. Melt temperature should remain below 240 °C; excursions above 250 °C can initiate oxidative chain scission, gel formation, and discolouration. The recommended die gap is 1.5–2.5 mm. Die gaps below 1.2 mm may raise extruder head pressure above 35 MPa, increasing the probability of melt fracture and limiting output. On a 50 mm grooved-feed extruder having 24:1 L/D and a 100 mm die, output is commonly 40–80 kg/h; the achievable rate depends on screw geometry, die lip set, air-ring capacity, and internal bubble cooling. Bubble stability is managed by maintaining blow-up ratio between 2.0:1 and 3.0:1 and frost-line height between 6 and 10 die diameters. Blow-up ratios above 3.5:1 frequently produce circumferential thickness variation and bubble oscillation; blow-up ratios below 1.8:1 reduce transverse mechanical properties and may lead to haul-off splitting.

Because butene-based LLDPE has less long-chain branching than high-pressure LDPE, shear thinning is lower and head pressure at a given screw speed may be higher. On low-torque extruders, blending EFDA-7047 with 10–30 wt% LDPE reduces head pressure and improves bubble stability. The blend, however, dilutes dart impact and tear relative to the neat LLDPE film; the reduction becomes more pronounced above 30 wt% LDPE. Purging after production should be performed with a lower-melt-index LDPE or HDPE, and molten EFDA-7047 should not be held in the die at high temperature for extended periods. During start-up, a starch-based or LDPE purge compound can remove previous resin residuals; the die lips should be inspected for degraded material before thin-gauge production.

Gauge reduction is not linear in mechanical response. When film thickness drops from 40 µm to 25 µm, dart impact can decrease by more than 50 % because the energy-absorbing volume decreases and process-induced orientation increases. The exact reduction depends on blow-up ratio, frost-line height, and internal bubble cooling. Lines with insufficient cooling often exhibit gauge bands in the bubble, producing local weak points and reduced seal integrity. Installing a high-velocity dual-lip air ring and internal bubble cooling improves gauge uniformity and permits higher output; converter-specific optimisation is required for the individual die and air-ring configuration.

Process regrind from edge trim and start-up film may be re-introduced at 20–30 wt% if it is dry and has not experienced more than three heat histories. Higher regrind levels tend to raise gel counts and lower dart impact; pigment masterbatches and printed trim introduce additional variables. No intentionally added heavy-metal-based deactivators are included in the base stabilisation package.

When LDPE or Hexene-Based LLDPE Substitution Is Considered in the Same Film Structure

Substitution decisions are normally made on a cost-to-performance basis and require comparison of film properties under identical test methods. Relative to high-pressure LDPE of similar melt index and density, EFDA-7047 shows higher tensile stress at break and higher dart drop impact because the linear backbone and short-chain branching distribution improve tie-chain formation. However, low long-chain branching reduces melt elasticity and shear thinning, which narrows the bubble-stability window and raises extruder head pressure. LDPE addition at 10–30 wt% is the usual remedy on conventional lines. At 50 wt% LDPE, bubble handling approaches that of LDPE, but the film loses a significant fraction of the LLDPE impact strength.

Compared with hexene- and octene-based LLDPE grades at similar density and melt flow rate, EFDA-7047 generally exhibits lower dart impact, especially at freezer temperatures. The shorter C4 branch is less efficient at generating interlamellar tie molecules than C6 or C8 branches; as a result, a butene-based film may require greater thickness or lower melt flow rate to match the impact resistance of a hexene-based film in identical gauge. Published data for direct comparison under identical blown-film conditions are limited; the magnitude of the difference depends on catalyst type, comonomer distribution, bubble geometry, and cooling rate. For frozen-food packaging and high-speed form-fill-seal lines, the low-temperature toughness gap is operationally significant and should be verified by whole-package drop tests at the intended storage temperature.

Relative to metallocene-catalysed LLDPE, Ziegler-Natta-based butene grades such as EFDA-7047 generally have broader short-chain branching distribution, lower clarity, and a broader processing window on conventional blown-film lines. Metallocene grades typically exhibit higher dart impact, lower seal initiation temperature, and lower extractables at equivalent density and melt flow rate; however, converter-specific data are required because the catalyst family alone does not determine molecular weight distribution or additive response.

Regulatory replacement of a hexene-based resin by EFDA-7047 does not automatically change food-contact status because the base polymer is specified for olefin polymers under FDA 21 CFR 177.1520(c) and EU Regulation (EU) No 10/2011. Any LDPE or other polyolefin used in the same structure must carry the same positive-list compliance documentation. Overall migration testing on the finished multi-layer article is required because adhesives, inks, and tie layers are not covered by the base resin compliance.

In heavy-duty sack conversion at 100–150 µm, the functional requirements are dart drop impact, tear resistance, seal strength, and stiffness sufficient for high-speed filling. EFDA-7047 is processed with internal bubble cooling and typically sealed at jaw temperatures of 95–105 °C; the sealing window broadens with LDPE addition. Surface treatment for flexographic printing should be maintained at 38–42 dyn/cm in accordance with ASTM D2578-17. Lower dyne levels can produce ink adhesion loss after multi-ply lamination or after sack filling. Agricultural greenhouse and mulch films require addition of hindered amine light stabilisers and UV absorbers; the base resin does not provide weathering resistance. In lamination film, EFDA-7047 is commonly blended with LDPE at 20–40 wt% to control draw resonance and neck-in in extrusion coating; melt temperature may be raised to 220–240 °C for adhesion to primed polyester or aluminium foil, but residence time must be minimised to avoid gel defects.

In coextruded barrier structures, EFDA-7047 is used as a sealant skin or abuse layer because it provides heat-seal strength and conformability. When adjacent to polyamide or EVOH, tie layers based on maleic anhydride-grafted polyethylene are required; the interfacial compatibility is governed by the tie-layer specification, not by the LLDPE grade alone. Processing of the EFDA-7047 skin at 180–200 °C helps preserve layer uniformity when coextruding with lower-viscosity barrier melts. Additive incorporation follows standard LLDPE practice: antiblock masterbatch loadings of 2–4 wt% and slip masterbatch loadings of 1–3 wt% are typical for thin film, but the precise level depends on gauge, blocking tendency, and downstream storage conditions. Inorganic antiblock above 5 wt% can reduce dart impact and haze; insufficient antiblock below 0.5 wt% may lead to blocking on warm winder rolls. In frozen-food packaging, low-temperature dart impact is determined by whole-package drop tests at the intended storage temperature; if the final structure is required to perform below -20 °C, a hexene-based or higher-density resin may be required.