For heavy-duty industrial sack structures between 120 µm and 180 µm, ExxonMobil Enable mLLDPE 23-05NA is commonly introduced into the core layer at 40 wt% to 60 wt%, with a fractional-MFI LDPE component at 20 wt% to 30 wt% and a C4-LLDPE or recycled trim making up the balance; the resin’s nominal density of 0.923 g/cm³ per ASTM D1505 and melt flow rate of 0.5 g/10 min per ASTM D1238 at 190°C/2.16 kg place it in the high-toughness blown-film segment, not in a cast-film viscosity envelope. The dilution with LDPE is not solely economic: the narrow molecular weight distribution of metallocene PE raises screw pressure in a 24:1 L/D barrier screw by 8% to 15% versus a conventional C4-LLDPE at the same rpm, and bubble stability on a 350 mm die with a 1.8 mm to 2.2 mm die gap becomes the controlling variable once blow-up ratio exceeds 2.5:1. Melt temperature at the die is held between 193°C and 221°C, because excursions above 232°C generate gel clusters that appear as arrowhead defects at the winder and cause dart-impact outliers. Film properties are fixed at the line gate: a 150 µm three-layer film commonly carries a minimum dart drop acceptance of 750 g by ASTM D1709 Method A and machine-direction Elmendorf tear above 7.0 N by ASTM D1922. Finished sacks are filled with 25 kg of granulate and drop-tested at 1.6 m according to ISO 7965-2:2009, with no rupture permitted for export container stuffing. For non-food industrial packaging, compliance is governed by REACH thresholds and, where recycled trim is incorporated, by PAH limits under AfPS GS 2019:01 PAK; a supplier declaration of heavy-metal content is required before film enters the warehouse.

What becomes of seal strength in −25°C frozen-food films?

At −25°C, seal strength in a PE/PE pouch is governed less by ultimate tensile than by sealant-layer continuity, seal-bar temperature, and slow-rate puncture resistance; ExxonMobil Enable mLLDPE 23-05NA is run as the sealant web at 18 µm to 25 µm against a 70 µm to 90 µm MDPE or HDPE core in a three-layer blown film line with a 1.5 mm to 2.0 mm die gap and a blow-up ratio of 2.0:1 to 2.5:1. The die melt temperature is held at 191°C to 216°C; raising the setpoint to improve clarity above 220°C narrows the heat-seal window and accelerates gel formation in the sealant layer. Heat-seal initiation is evaluated by ASTM F88/F88M with 0.4 MPa seal-bar pressure and 0.5 s dwell; the target range is 95°C to 105°C. Hot-tack behaviour is measured by ASTM F1921 across the same temperature range, because freezer pouches are filled on vertical lines where the seal is loaded by product weight before solidification. Low-temperature puncture resistance is checked by ASTM F1306 at −25°C after conditioning; this test separates ductile puncture from brittle fracture at gusset folds. Migration compliance rests on FDA 21 CFR 177.1520(c) 3.1a/3.2a and EU 10/2011, with overall migration limits tested by EN 1186; because 23-05NA is a barefoot resin, converters can avoid additive-related migration uncertainty in direct food contact, provided the sealing layer is not blended with non-food grades. A practical failure occurs when seal-bar setpoint drops below 90°C: the sealant wets the core interface incompletely, and the pouch leaks after freezer compression at −25°C, even though room-temperature peel values appear acceptable.

Silage clamp covers and bale-wrap outer films impose UV, oxygen ingress, and puncture demands simultaneously, and a 150 µm monolayer structure built on ExxonMobil Enable mLLDPE 23-05NA is commonly stabilised with 2 wt% to 4 wt% of a HALS/UV-absorber masterbatch added at the feed throat. The blown film line runs a 2.0 mm to 2.4 mm die gap at 1.8:1 to 2.2:1 blow-up ratio, and melt temperature is deliberately capped at 190°C to 210°C to protect thermally sensitive HALS packages from decomposition. Oxygen transmission is thickness-controlled; a 150 µm film of this density class registers roughly one-third the oxygen transmission rate of a 50 µm film when tested under ASTM D3985 at 23°C and 0% RH. Puncture and tear retention after weathering are more decisive than initial mechanical values: dart impact by ASTM D1709 Method A and Elmendorf tear by ASTM D1922 are measured at installation, and accelerated ageing under ISO 4892-2 is used to detect embrittlement before field failure. The relevant product standard for silage covers is EN 13206:2017, which requires declaration of nominal thickness, mechanical classification, and UV-stabilisation category; converters must not rely on virgin resin stability alone. Field experience on Southern European clamps shows that stabiliser dosing below 1.5 wt% leads to edge cracking after extended direct exposure, though published data specific to 23-05NA UV retention under a particular latitude is limited. The film is also checked for blocking tendency because barefoot metallocene PE windings in high-UV environments can fuse if storage temperature exceeds 45°C; a separate antiblock masterbatch is introduced only when demanded by the silage cover end-user, because excessive antiblock raises haze and reduces tear resistance.

When 23-05NA is downgauged from 80 µm to 55 µm in can liners

Downgauging a can liner from 80 µm to 55 µm at constant output requires a resin with sufficient dart impact and tear resistance to survive sharp waste edges, and ExxonMobil Enable mLLDPE 23-05NA is used at 60 wt% to 80 wt% with an LDPE or recycled content balance to maintain bubble stability. A two-layer line with a 2.3 mm die gap and 2.8:1 to 3.2:1 blow-up ratio typically barrels the resin at 185°C to 205°C and positions the frost line at 5 to 7 die diameters above the air ring; if the frost line rises beyond that zone, film blocking and gauge bands become worse than the downgauging benefit. Acceptance is set by ASTM D1709 Method A with a minimum of 220 g for 55 µm, and machine-direction tear by ASTM D1922 above 3.5 N; these values are used because a 55 µm 23-05NA-rich liner must match the abuse resistance of a conventional 80 µm LLDPE/LDPE blend. For household refuse sacks, EN 13592:2017 governs tensile, tear, and dart impact requirements; industrial can liners sold into non-household channels use supplier-specific specifications derived from the same test methods. A recurring production failure is gel-induced dart variability at line speeds above 75 m/min, when unmelted polymer particles pass through short screws and create weak points that are not visible to inline cameras; a 30:1 L/D grooved-feed extruder with barrier mixing is preferred over older 24:1 L/D screws. Because the resin is barefoot, winding at high tension above 120 N/m on a surface winder induces blocking after 48 h of storage above 35°C; quarantine checks of reel hardness and blocking force prevent converting-room downtime.

Form-fill-seal sealant webs in high-speed vertical pouches

At 80 cycles/min on a vertical form-fill-seal machine, the sealant layer is only 15 µm to 25 µm of ExxonMobil Enable mLLDPE 23-05NA inside a total film of 70 µm to 110 µm, and the controlling property is hot tack rather than ultimate seal strength. A three-layer blown film die with 1.5 mm to 2.0 mm gap runs at 2.0:1 to 2.3:1 blow-up ratio; melt temperature is set between 188°C and 210°C, because higher temperatures accelerate slip-free blocking on the winder and do not improve hot tack. Seal performance is mapped by ASTM F1921 at 0.35 N/mm² seal pressure and 0.3 s dwell, and the useful hot-tack window is defined as the temperature range above the point where the seal fails cohesively below 1.5 N/25 mm. Peel strength after cooling is recorded by ASTM F88/F88M and should remain above 10 N/25 mm at a seal temperature of 115°C; values below this fail in drop tests with granular fill. Because the sealant web is lamination-grade with no slip or antiblock, surface treatment to 40 mN/m to 44 mN/m by ASTM D2578 is required before lamination to the outer print web. Food contact compliance is established under FDA 21 CFR 177.1520(c) 3.1a/3.2a and EU 10/2011, with overall migration tested per EN 1186; after lamination, the finished pouch is also checked for seal integrity through pinhole and dye-penetration protocols tied to ASTM F3039.

Extrusion lamination of a blown sealant web differs from cast sealant lamination in cooling rate and residual thermal stress: the 23-05NA web is produced at 20 µm to 30 µm, laminated to a biaxially oriented polyethylene core, and used in mono-material PE/PE pouches for dry foods and non-food powders. The blown film step uses a 1.8 mm die gap and 2.0:1 blow-up ratio; the film is immediately surface-treated to 42 mN/m and wound at low tension to avoid flat spots. Adhesion to the oriented core is tested by ASTM F904 and must exceed 3.0 N/25 mm; failure is usually traced to backside treatment transferring to the sealant surface or to slip additive bloom from the pouch outer layer. The mono-material structure is assessed for recyclability under CEFLEX design-for-recycling guidelines, and the sealant layer must not contain incompatible barrier polymers, aluminium, or adhesive systems that disrupt polyethylene recovery streams. Heat-seal data on the finished laminate follow ASTM F88/F88M, with a target seal initiation of 95°C to 105°C at 0.4 MPa and 0.5 s dwell; this window allows the converter to seal without melting the oriented PE core in the same dwell cycle. A known limitation is that blown sealant webs of this density class are more sensitive to die-lip buildup than C4-LLDPE, so die cleaning intervals shorten when throughput exceeds 180 kg/h on a 450 mm die; operators track die-lip deposit formation with an inline surface-defect camera to avoid seal contamination.