Ethylene-octene linear low-density polyethylene grade DOWLEX 2307G, with a nominal density of 0.917 g/cm³ by ASTM D792 and a melt index of 2.3 g/10 min by ASTM D1238 at 190°C under 2.16 kg load, is processed on grooved-feed blown film lines for heavy-duty industrial liners and sacks. On a production-scale line built around a 75 mm grooved-feed extruder with 30:1 L/D and a 300 mm spiral mandrel die, a 50 µm monolayer liner is processed at melt temperatures between 199°C and 221°C. The die gap is held between 1.4 mm and 1.8 mm, and the blow-up ratio is set from 2.5:1 to 3.2:1. Raising the blow-up ratio to 3.2:1 shifts the molecular orientation balance; transverse direction Elmendorf tear by ASTM D1922 improves, while bubble breathing and side-gust instability increase if the frost line is positioned below 700 mm from the die face. To stabilize a 50 µm bubble at ambient line speeds of 80–120 m/min, the frost line is held between 850 mm and 1,100 mm. Thickness profiling with a capacitance gauge is used to hold ±5% deviation across the web, and air ring flow is adjusted in 10% increments until the frost line height stabilizes. The resulting film is slit into panels for chemical bag liners, construction debris sacks, and flexible intermediate bulk container liners. In blended structures, LDPE of melt index 0.25–0.5 g/10 min is added at 20–30 wt% to widen the bubble stability window; at 60:40 LLDPE:LDPE, dart impact by ASTM D1709/A is reduced to a point where heavy-duty sack specifications require re-qualification. For U.S. food-contact applications, the olefin polymer regulation 21 CFR 177.1520(c) applies with end-use condition selection based on food type and temperature. European direct food-contact evaluations require overall migration below 10 mg/dm² under EN 1186-1 and verification of specific migration for 1-octene under Regulation (EU) No 10/2011, with the published specific migration limit of 15 mg/kg for 1-octene in the Union list. For non-food industrial sacks exported to the European Union, packaging heavy metals requirements are controlled under Directive 94/62/EC with a combined limit of 100 mg/kg for lead, cadmium, mercury, and hexavalent chromium.

What Limits Thickness Uniformity in Cast Stretch Wrap Extruded from 2307G?

On cast film lines with 90–120 mm smooth-barrier screws and 2.2–2.8 m flat dies, DOWLEX 2307G is drawn down to 15–25 µm at line speeds of 250–500 m/min. The melt temperature is maintained between 232°C and 260°C, the air gap set at 80–150 mm, and the chill roll temperature controlled to 16–24°C. Thickness uniformity across the web is governed by draw resonance and edge neck-in; draw resonance begins as sustained oscillation in transverse gauge when the draw-down ratio exceeds approximately 20:1, and it is managed by adjusting the air gap and melt temperature rather than by increasing line speed alone. Thickness profiles are measured by ISO 4593, with cast stretch converters usually rejecting rolls where the 2σ gauge variation exceeds ±1.5 µm in a 20 µm film. Because the 0.917 g/cm³ density grade has lower modulus than high-density polyethylene, film tension must be limited to avoid machine-direction elongation during winding. Formulations for machine stretch wrap commonly blend 70–85 wt% DOWLEX 2307G with 15–30 wt% metallocene LLDPE or LDPE of melt index 0.5–2.0 g/10 min to modify cling and puncture. Cling additive masterbatch is let down at 2–5 wt%; above 5 wt% the film can block on the roll during storage above 35°C. Puncture resistance is measured by ASTM D5748, and stretch force is measured at 200% elongation by ASTM D5459. The finished films are converted into hand wrap, power pre-stretch pallet wrap, and vented pallet overwrap for non-food logistics. Because cast stretch film is often stored in high-ambient-temperature warehouses, blocking resistance is checked by ASTM D3354.

In extrusion lamination and extrusion coating, DOWLEX 2307G is introduced at 10–25 wt% into an LDPE-rich melt stream to increase seal strength and hot tack without causing the severe neck-in and draw-down limitations seen with pure LLDPE. The coating line is typically configured with a 90–120 mm extruder, 30:1 L/D, and a flat die with a 0.5–0.8 mm die gap. Melt temperatures are held between 260°C and 290°C because higher temperatures reduce melt elasticity and improve adhesion to aluminum foil and corona-treated paperboard. Coating weights range from 12 g/m² to 30 g/m² at line speeds of 100–250 m/min. Ozone treatment at 1.0–2.5 kW is applied to the melt curtain to increase polar surface oxidation; adhesion is then measured by T-peel according to ASTM F88 or by the converter’s internal scoring procedure. The coated substrates are converted into sachet laminates, aseptic carton inner liners, and retort pouch sealant webs where the food-contact layer is evaluated under 21 CFR 177.1520(c) in the United States and under Regulation (EU) No 10/2011 in the European Union. Published data for this specific grade in high-speed coating is limited; converter trials are required to establish the maximum line speed before melt-curtain sag and adhesion loss exceed specification.

When 2307G Replaces LDPE in Frozen Food Packaging Sealant Webs

DOWLEX 2307G is used as the sealant layer in coextruded blown film for frozen food pouches where low-temperature toughness and seal integrity through ice crystals are required. The structure commonly places the sealant layer at 15–25% of total film thickness, bounded by a tie layer and a polyamide or EVOH barrier core. In a 7-layer blown film die, the sealant layer extruder is run at 190°C–210°C, while barrier-layer extruders run at 220°C–240°C for EVOH or 240°C–260°C for polyamide; the die is held at 220°C–230°C to avoid excessive residence time for the barrier material. Seal strength is measured by ASTM F88 on 25.4 mm wide strips sealed at 121°C, with converters specifying a minimum based on fill weight and drop-test protocols. Because DOWLEX 2307G is an ethylene-octene copolymer, its low-density amorphous fraction maintains flexibility below -30°C, but qualification for freezer applications still requires dart impact by ASTM D1709/A and Elmendorf tear by ASTM D1922 on the finished laminate. Food-contact documentation includes FDA 21 CFR 177.1520(c) for olefin polymers in contact with aqueous and fatty foods under Conditions of Use B through H, and the European Regulation (EU) No 10/2011 with overall migration tested by EN 1186-1. The specific migration limit for 1-octene is 15 mg/kg; converters using higher octene-comonomer grades should verify compliance by migration testing according to EN 13130-1 or equivalent. The converted articles include frozen vegetable pouches, seafood ice-glaze films, and bag-in-box liners for chilled liquid products.

Agricultural Silage Wrap: UV Stabilizer Loading and Oxygen Transmission Constraints

In blown film for baled silage, DOWLEX 2307G is processed at 25–35 µm thickness with a UV stabilizer masterbatch that contains hindered amine light stabilizers and a titanium dioxide-based white concentrate. The masterbatch is let down at 4–8 wt%; below 4 wt%, UV protection is insufficient for 12-month outdoor exposure, and above 8 wt% the film may lose tear strength by ASTM D1922 because the high loading reduces melt integrity. The film is produced on the same grooved-feed blown film equipment used for industrial liners, with a blow-up ratio of 2.5:1–3.0:1 and melt temperatures of 190°C–210°C. Oxygen transmission measured by ASTM D3985 is thickness-dependent; converters relying on LLDPE for silage wrap must balance oxygen intrusion against the anaerobic fermentation requirement, but LLDPE is not a barrier polymer and must not be specified for long-term oxygen exclusion. Puncture resistance by ASTM D5748 and tear resistance by ASTM D1922 are used to qualify rolls for bale wrap, because failure in the field occurs as pinholes at the bale surface. The converted product is applied to round and square bales using mechanical wrappers that pre-stretch the film to 55–70% elongation; the film must retain its cling after pre-stretch and must not tear at the overlap edges. For European agricultural plastics, compliance with Regulation (EC) No 1907/2006 (REACH) and with the relevant national schemes for agricultural film collection is required.

Layer Distribution in Coextruded Barrier Films Requires Independent Melt Temperature Control

In multilayer blown film for meat and cheese packaging, DOWLEX 2307G is placed in the outer or inner skin layers to deliver sealability and abuse resistance while the core layers contain polyamide, EVOH, or ethylene vinyl alcohol-based barrier resins. The die is typically a 5-layer or 7-layer spiral mandrel system with separate melt channels; the skin layer containing 2307G is maintained at 190°C–215°C, and the barrier core is maintained at its recommended processing temperature. Layer thickness ratio is controlled by gravimetric feeders and melt pumps; a typical ratio of 30:15:10:15:30 is used for a 5-layer structure where the outer skins are LLDPE-rich and the core is EVOH. Seal initiation temperature is evaluated by sealing at 100°C–130°C and measuring strength with ASTM F88. Because the ethylene-octene copolymer contains no plasticizer and has a lower melt temperature than polyamide, interlayer adhesion is provided by anhydride-modified tie resins at 5–10% of total thickness. The converted articles include vacuum pouches, modified atmosphere packaging lidding, and dairy film where puncture resistance and seal integrity are specified. Processors must avoid stagnation in the die; melt residence times above 10 minutes at 230°C can cause gel formation, but published data for this specific grade in such structures is limited and must be generated on the actual die geometry.