Grade identification data for SABIC SUPEER mLLDPE 7118NE establishes the baseline from which all downstream application parameters derive. The material is a butene-comonomer metallocene linear low-density polyethylene with a nominal density of 0.918 g/cm³ measured by ISO 1183-1:2019 and a melt flow rate of 0.8 g/10 min measured at 190°C/2.16 kg by ISO 1133-1:2022. Peak melting temperature determined by differential scanning calorimetry (ISO 11357-3:2018, second heating cycle at 10°C/min) falls within 108–118°C, and the Vicat softening point (ISO 306:2022, Method A50) lies between 97°C and 102°C. The metallocene single-site catalyst technology yields a molecular weight distribution approximating 2.0–2.5, compared with 3.5–4.5 for conventional Ziegler-Natta LLDPE of equivalent density. This narrow distribution is the root cause of the grade’s two most consequential processing behaviors: reduced shear thinning in the extruder (elaborated in the first scenario below) and constrained melt strength at the bubble (discussed in the second scenario). The grade suffix NE denotes a natural-grade designation; no pre-compounded slip, antiblock, or processing aid additive package is present in the granule, and converter-side additive introduction is therefore a mandatory formulation step in every scenario presented.

What Governs Seal Initiation Temperature and Hot Tack in High-Clarity Food Packaging Blown Films?

The dominant processing conflict in monolayer food packaging conversion arises from the combination of low shear thinning and constrained melt strength. On a 65 mm smooth-bore extruder equipped with a barrier screw of L/D 30:1 and a Maddock mixing section, extrusion of 100% 7118NE at a melt temperature of 205°C typically produces melt pressure at the die entry 15–20% higher than a Ziegler-Natta LLDPE of equivalent density and MFR under identical screw speed. The apparent viscosity ratio derived from capillary rheometry at 100 s⁻¹ and 1000 s⁻¹ at 190°C approaches 1.0, whereas conventional LLDPE of the same density class returns 1.5–1.8, confirming that the material cannot safely operate on dies or adapters rated below 40 MPa without derating output. The industry-standard starting formulation is therefore 80 wt% 7118NE blended with 20 wt% autoclave LDPE (MFR 0.7 g/10 min, density 0.923 g/cm³), a combination that restores shear thinning and stabilizes the bubble against stalk oscillation. Existing blown film lines originally specified for LDPE-only operation with a die gap of 0.8 mm must be reconfigured to 1.8–2.2 mm; the narrow molecular weight distribution generates excessive die lip shear stress and surface melt fracture below that range. Blow-up ratio is held at 2.2:1–2.8:1, and the frost line height is set at 3–4 die diameters below the die head to retain moderate MD orientation without degrading dart drop impact.

Compliance in the food contact domain is anchored to FDA 21 CFR 177.1520(c)3.2a, which authorizes olefin polymers intended for repeated and single-use food contact under the applicable conditions of use; the grade is also within scope of EU Regulation (EU) No 10/2011, with overall migration testing required to remain below 10 mg/dm² (Article 12, Annex I) using food simulant D1 for fatty foods and simulant A for aqueous foods. Specific migration of the butene comonomer is not assigned a numeric limit under current harmonized SML tables, but converters must document compliance through extraction testing per EN 1186 methodology. The natural designation mandates the addition of 2–3 wt% slip/antiblock masterbatch (erucamide slip at 500–800 ppm active concentration, synthetic silica antiblock at 1500–2500 ppm active concentration) to prevent blocking during rewind at roll diameters exceeding 400 mm. Terminal products in this configuration include bakery bread wraps, high-clarity produce bags, and sandwich overwrap structures where a 50 µm monolayer achieves haze below 12% (ASTM D1003) and dart drop impact exceeding 350 g (ASTM D1709, Method A).

Collation Shrink Film MD/TD Shrink Force Balance and Bubble Geometry

High-stalk blown film geometry, rather than the conventional in-pocket configuration, is the production mode under which 7118NE delivers its characteristic TD-dominant shrink vector. The stalk functions as a thermal annealing zone in which MD-oriented polymer chains relax prior to transverse biaxial stretching at the bubble; control of stalk collapse without lateral deformation is therefore a process variable as critical as the BUR itself. For a 250 ml single-serve bottle multipack, the target shrink vector is MD 5–12% free shrink and TD 45–60% free shrink measured at 120°C by ASTM D2732-20, with shrink force per ISO 14616:1997 distributed such that TD values exceed 8 N/15 mm to hold the collated pack under transit vibration. Formulations operating in this window typically comprise 70 wt% 7118NE, 25 wt% tubular LDPE (MFR 0.3–0.5 g/10 min), and 5 wt% HDPE (density 0.957 g/cm³, MFR 0.05 g/10 min) for stiffness and load-bearing capacity; the 7118NE fraction supplies optics, seal integrity at the shrink seam, and the mechanical strength that prevents can-edge puncture during shrink tunnel residence.

Extrusion requires a die gap of 1.8–2.5 mm, a BUR of 3.5:1–4.0:1, and a stalk height maintained at 4–6 die diameters; frost line height at 5–8 die diameters determines the final crystallinity that sets shrink force at the packaging line’s shrink tunnel operating range of 140–160°C. Melt temperature is held at 195–215°C, and internal bubble cooling (IBC) with chilled air at 10–15°C is specified when line speeds exceed 120 kg/h; the narrow MWD of 7118NE reduces the tolerance for IBC air pressure fluctuation, and excursions beyond ±5°C in cooling air temperature produce measurable asymmetry in TD shrink force across the layflat width. Compliance for collation shrink film intended for indirect beverage contact relies on EU Regulation (EU) No 10/2011 overall migration screening and FDA 21 CFR 177.1520; where the film overwraps unpackaged canned goods, converters must verify that the shade-side surface temperature during shrink tunnel residence does not exceed 70°C for a contact duration of 30 seconds. Terminal products include 6 × 250 ml water bottle collation packs, 4 × 330 ml can wraps, and promotional multi-pack bands of 150–250 µm pre-shrunk film where the HDPE fraction is increased to 10 wt%.

In cast film co-extrusion for lamination structures targeting snack food and single-serve condiment formats, the sealant web employing 7118NE is produced as the food-contact layer of a three-layer A/B/C cast film in which the core (B) layer is a Ziegler-Natta LLDPE for bulk stiffness and the back (C) layer is a copolymer polypropylene or HDPE for heat resistance during downstream adhesive lamination. The 7118NE sealant layer is specified at 15–25 µm within a total cast web thickness of 40–60 µm, used either at 100 wt% or in a 90/10 wt% blend with autoclave LDPE when chill roll blocking becomes limiting at line speeds above 300 m/min. Processing on a 90 mm cast film extruder with a T-die coat-hanger manifold and a chill roll temperature of 20–28°C requires melt temperature between 220°C and 240°C; the natural grade’s absence of internal lubricants demands the addition of 2–3 wt% slip/antiblock masterbatch before any rewind at roll diameters above 350 mm. Compliance is maintained under EU Regulation (EU) No 10/2011 Article 12 overall migration (10 mg/dm² using simulant A for aqueous foods and D1 for fatty snack oils) and FDA 21 CFR 177.1520(c)3.2a; for Japanese export formats, the converter must additionally reference MHLW Notification No. 370. Terminal products include three-layer adhesive-laminated snack pouches (PET / aluminium / cast web), single-serve sachet stock for ketchup and mayonnaise formats, and dry powder beverage stick-pack film where seal integrity per ASTM F88/F88M-23 must exceed 15 N/25 mm at peak load. A known boundary condition applies: the seal initiation temperature of butene-mLLDPE of this density class is 4–7°C higher than an equivalent hexene-mLLDPE, and for high-speed vertical form-fill-seal lines running beyond 80 packs/min, a converter must verify that dwell time at the seal jaw provides sufficient enthalpy transfer to reach the 95–101°C initiation threshold measured by ASTM F1921 at 0.5 N/25 mm hot tack.

When Dart Drop Impact at -18°C Becomes the Controlling Specification for Frozen Food Webs

At chamber conditioning temperatures of -18°C maintained for 24 h in freezer distribution trials, the controlling specification for 7118NE-based webs shifts from room-temperature dart drop to a composite of sub-zero puncture resistance, low-temperature Elmendorf tear (ASTM D1922), and seal creep under freeze-thaw cycling. The base resin’s butene comonomer content yields a glass transition temperature far below the test temperature, so the material remains ductile; however, the narrow molecular weight distribution exerts a measurable effect on low-temperature tear resistance, and the controlling parameters shift from impact alone to the combination of puncture resistance (simulating frozen pea and French-fry sharp edges) and seal integrity at freezer cycling. The converter-standard formulation for IQF vegetable and frozen seafood bags blends 65 wt% 7118NE with 35 wt% LDPE (MFR 0.7 g/10 min, density 0.923 g/cm³), or substitutes 15 wt% of the LDPE fraction with EVA (VA content 9–12%, MFR 1.0 g/10 min) where the packaging line seals through contaminated seal areas laden with moisture, starch dust, and particulates. Blown film processing requires a die gap of 1.8–2.2 mm, a BUR of 2.5:1–3.0:1, and an elevated frost line height of 4–5 die diameters, because a lower frost line quenches the amorphous phase too rapidly and increases the incidence of dart drop failures under frozen conditioning by 20–30% in converter trials.

Regulatory compliance for frozen food packaging invokes FDA 21 CFR 177.1520(c)3.2a under frozen storage conditions without thermal treatment in the package, and EU Regulation (EU) No 10/2011 with food simulant A (10% ethanol for aqueous frozen foods) or D2 (vegetable oil for fatty frozen products such as ready-to-bake croissants). Cryogenic flex endurance, when specified, is evaluated by repeated folding at -18°C through 10,000 cycles per ISO 7854:1995 Method A (Gelbo flex), with failure defined as pinhole formation detected by dye penetration; published data for this specific 7118NE configuration is limited, and each converter must establish its own pass-fail correlation against the packaged product’s weight and fill volume. Terminal products include IQF vegetable printed bags of 35–50 µm thickness, frozen seafood vacuum skin web stock, and ice cream overwrap where the resin contributes gloss below 15% haze (ASTM D1003) at 40 µm. An operational boundary: the natural grade lacks internal slip, and in humid freezer warehouse environments with repeated thaw-condensation cycles, insufficient slip masterbatch loading below 500 ppm erucamide results in roll-to-roll blocking during unwinding on automated bag-forming machines.

Form-fill-seal (FFS) conversion for 25 kg granular petrochemical and mineral fertilizer sacks represents a well-established application zone where 7118NE is introduced not for optical properties but for impact toughness and seal integrity under high fill weight. The practical formulation is a three-layer co-extrusion in which 7118NE occupies the inner sealant layer at 35–45 wt% of the total structure, with an HDPE film grade (density 0.952–0.960 g/cm³, MFR 0.05–0.3 g/10 min) in the outer and middle layers for load-bearing stiffness and creep resistance; a third component, Ziegler-Natta LLDPE C4 (MFR 1.0 g/10 min), is added at 15–20 wt% to the inner layer to prevent seal-area thinning during high-speed FFS jaw closure. Total film thickness ranges from 80 µm for low-density fertilizer to 150 µm for denser petrochemical pellets, produced on a three-layer blown film line with die diameter 200–350 mm, internal bubble cooling, maximum output 300–500 kg/h, and melt temperature 200–225°C. The governing compliance standard for filled sack performance is ISO 7965-2:2022, which specifies drop testing of filled sacks from drops of 1.2 m on the base edge and 1.0 m on the face, with pass criterion defined as no product leakage; supplementary crease resistance is evaluated per ISO 5416 or the historical ASTM D638 tensile equivalence. Terminal products include stacked 25 kg polyolefin granule sacks, ammonium nitrate and urea 50 kg fertilizer bags, and silica sand packaging where the sealant continuity of the 7118NE layer provides a dust-tight weld seam. Published data for the specific ternary blend ratio in FFS sack production is limited; the performance range cited above reflects converter-driven qualification data. The natural designation requires slip/antiblock introduction, but at reduced antiblock loading of 800–1200 ppm silica because the sack’s external surface requires sufficient coefficient of friction against palletized stacking without slipping.

Agricultural Silage Wrap Exhibits a Distinct Formulation Conflict Between Pre-Stretch Retention and Puncture Propagation Tear Resistance

Opposing requirements of high pre-stretch at the baler and sustained puncture resistance against lucerne stalks, maize stubble, and twig inclusions in the bale periphery define the formulation envelope for 7118NE in silage wrap production. The base resin’s narrow molecular weight distribution confers excellent elastic recovery after pre-stretch, which is why it is selected for this application; however, the grade alone lacks the surface tack required for film-to-film self-adhesion at 55–65% baler pre-stretch, and must be blended with tacky comonomers. The industry-standard cast film formulation for a 750 mm round bale wrap comprises 55 wt% 7118NE, 25 wt% EVA (VA content 14–18%, MFR 1.5–2.0 g/10 min), and 20 wt% VLDPE (density 0.905–0.912 g/cm³, MFR 1.0 g/10 min), extruded at 230–250°C on a single-screw cast film line with a chill roll temperature of 15–20°C and a final film thickness of 20–25 µm. The 7118NE fraction supplies the elastic recovery measured as residual tension at 24 h post-stretch per EN 13207:2018 Annex C methodology; the EVA supplies tack; the VLDPE component lowers the elastic modulus to prevent neck-in during baler pre-stretch.

Compliance is defined by EN 13207:2018, which specifies tensile strength in MD and TD, elongation at break, dart drop after aging, and UV stability classification after 1200 h of QUV-B exposure per ISO 4892-3; converters supplying European agricultural markets must document that the formulated film retains at least 50% of original elongation after the specified UV aging interval. Because the NE designation confirms the absence of a pre-compounded additive system, 0.5–1.0 wt% of a HALS/UV absorber synergistic masterbatch (HALS loading 2500–5000 ppm active) must be compounded into the formulation before extrusion; without this addition, outdoor storage life of wrapped bales falls below 6 months under southern European solar irradiance. Terminal products include 750 mm × 25 µm round bale wrap in 1600 m rolls, 500 mm × 25 µm square bale wrap, and silage clamp films of 100–150 µm thickness where the 7118NE fraction is reduced to 30–40 wt% to accommodate greater stiffness. An operational boundary: the formulation must not be combined with amine-based antistatic masterbatches or heat stabilizers, because the fermentation acids (lactic and acetic acid, typical pH 4.0–4.5 inside the silage mass) neutralise amine functionality and can migrate to the film surface as a visible haze, reducing both tack and UV stabiliser effectiveness.