Commercial designation SABIC SUPEER mLLDPE 8112 identifies a metallocene-catalysed linear low-density polyethylene supplied as a pelletized blown film resin. The grade is differentiated from conventional Ziegler-Natta LLDPE film resins by its single-site catalyst architecture, which produces a narrow molecular weight distribution and a more uniform distribution of short-chain branching. Typical lot-release data reported by the supplier list a melt flow rate of 1.0 g/10 min at 190 °C under 2.16 kg load when tested to ISO 1133-1, and a nominal density of 0.912 g/cm³ tested to ISO 1183-1. These values are not sales specifications; the certificate of analysis for a specific lot should be consulted. Commercial applications reported for the grade include primary sealant webs in coextruded form-fill-seal pouches, heavy-duty shipping sacks, frozen food packaging, collation shrink film, and lamination substrates. Regulatory suitability for food contact is subject to grade-specific certification under FDA 21 CFR 177.1520(c) and Commission Regulation (EU) No 10/2011, with compliance determined by the finished article rather than by the pellet alone.

The base polymer is an ethylene/alpha-olefin copolymer produced by a metallocene catalyst. The single-site nature suppresses the active-site drift found in multi-site Ziegler-Natta catalysts, so the comonomer is incorporated more evenly across the chain-length distribution. Gel permeation chromatography analyses generally show a polydispersity index lower than 3.0 for metallocene LLDPE, while conventional Ziegler-Natta LLDPE of similar melt index may display polydispersity values between 3.5 and 5.0. This reduces the low-molecular-weight fraction available for extractables during high-temperature extrusion and changes the crystalline chain folding after orientation. Storage of the resin follows standard polyethylene handling practice. Wet pellets from condensation at low warehouse temperatures are uncommon because the polymer is non-hygroscopic, but silo purging with dry air minimizes surface moisture on cold pellets when ambient humidity exceeds 60% relative humidity.

What Physical Property Shifts Are Measured When C4 Ziegler-Natta LLDPE Is Replaced on a Blown Film Line?

The primary structural distinction in SABIC SUPEER mLLDPE 8112 is the narrow molecular weight distribution generated by the single-site metallocene catalyst. Compared with a conventional C4 Ziegler-Natta LLDPE of equivalent 1.0 g/10 min melt flow rate, the metallocene grade contains a lower fraction of low-molecular-weight highly branched chains. That alteration suppresses internal scattering elements and changes the frozen-in crystallinity after film quenching.

In monolayer film evaluations carried out on a 60 mm grooved-feed blown film extruder operating with a 2.0:1 blow-up ratio and a 40 µm gauge, the direction of change is reproducible: dart drop impact under ISO 7765-1 Method A increases relative to the C4 comparative grade, and haze under ISO 14782 decreases. Commonly reported film property ranges at 40 µm gauge and 2.5:1 blow-up ratio are haze of 5–7% under ISO 14782 and dart drop impact of 800–1000 g under ISO 7765-1 Method A. The C4 Ziegler-Natta comparator typically falls within 9–12% haze and 350–500 g dart drop impact under identical conditions. These ranges reflect general class behaviour and are not a sale specification.

Elmendorf tear measured under ISO 6383-2 is not a single-value advantage. Machine-direction tear is often lower than a C4 Ziegler-Natta LLDPE because of orientation imparted by the narrow molecular weight distribution, while transverse-direction tear may be higher. A converter running a high-stalk bubble may see the balance shift; a low-stalk process may not. The test values in the specification table should therefore be read as one configuration, not as a universal property of the grade. Published data for this specific configuration is limited.

On a production blown film line equipped with a single-screw extruder of L/D 24:1 to 30:1 and a barrier screw, melt temperatures are maintained between 190 °C and 220 °C. Die gap is normally kept from 1.8 mm to 2.5 mm. Because the metallocene grade displays higher viscosity at low shear and less shear-thinning than LDPE, die pressure at constant output may increase by 10–30% relative to a 0.3 g/10 min LDPE. A wider die gap or an increased die temperature is used on some lines to reduce head pressure; however, widening the die gap without adjusting the frost line may degrade tear balance. At high output, sharkskin melt fracture appears earlier than with long-chain branched LDPE. Production lines frequently add a fluoropolymer processing aid masterbatch at an active level of 300–600 ppm to suppress die lip buildup and melt fracture; the minimum effective addition rate is die-specific and should be determined by trial.

The rheological consequence is an increased apparent shear viscosity at low shear rates. Capillary rheometry under ISO 11443 at 190 °C shows a less steep viscosity-shear rate curve than LDPE. At an apparent shear rate of 100 s⁻¹, the viscosity of this metallocene grade can exceed a 0.3 g/10 min LDPE by more than 20%, but at 1000 s⁻¹ the difference narrows because of shear thinning in the LLDPE. Extruder head pressure and motor load are therefore dominated by the die start-up period; once the melt is primed, throughput can be increased through the same die, but the margin to melt fracture is smaller than with a long-chain branched LDPE.

The difference between SABIC SUPEER mLLDPE 8112 and a high-pressure tubular LDPE in coextrusion is most visible at the outer skin layer. LDPE contributes melt strength and stabilises the bubble; the metallocene LLDPE contributes sealant performance but reduces melt extension at high deformation rates. When coextruding a three-layer structure with a core of LDPE and skins of this metallocene grade, the die lip gap must often be increased by 10–20% relative to an all-LDPE structure at the same gauge. Failure to do so can cause an unstable bubble pocket at the die exit and a visible flow line in the film. These effects are documented on industrial three-layer lines, but the exact die adjustment is dependent on die diameter and air ring design; published data for this specific configuration is limited.

When the Sealant Web Is Run at Low Jaw Temperatures on a Vertical Form-Fill-Seal Line

Seal initiation and hot tack behavior are central to the use of this grade in form-fill-seal packaging. The seal initiation temperature is evaluated under ASTM F1921 Method A at 0.275 MPa pressure and 0.5 s dwell, with a reported range typically below 100 °C for the neat film. Hot tack force is evaluated under ASTM F1921 Method B across a temperature ramp, and the useful hot tack plateau is narrower than the heat seal initiation curve would suggest.

A processing conflict arises in vertical form-fill-seal and horizontal form-fill-seal production when product protection requires jaw temperatures below 110 °C, but high-speed filling demands hot tack force above 2 N/15 mm during the first 0.2 s after sealing. The metallocene grade can move seal initiation to lower temperatures, but the hot tack plateau must be mapped on the specific jaw configuration and film structure. Multilayer structures with a 10–25 µm sealant layer are used to keep the sealing component at the surface while allowing core layers for stiffness and abuse resistance. In coextruded structures, the sealant web should not be blended with high levels of LDPE for low-temperature sealing, because long-chain branched polyethylene can broaden the melting curve and shift seal initiation upward; published data for this specific configuration is limited.

Specification Data for Pellet and Film Under Standardized Test Protocols

The film property values in this table are representative of a 40 µm monolayer film extruded at a 2.5:1 blow-up ratio, 210 °C melt temperature, and 2.0 mm die gap. They are not to be read as a sales specification and may vary with additive package and line conditions.

Compliance for food-contact use is not established solely by the pellet grade. The final packaging article must be tested according to Commission Regulation (EU) No 10/2011 for overall migration and specific migration limits, and in the United States under FDA 21 CFR 177.1520(c) for olefin polymers. For European food contact, overall migration limit of 10 mg/dm² for articles and 60 mg/kg for food simulants applies under Regulation (EU) No 10/2011; specific migration of additives and residual catalysts must be confirmed through analytical testing of the finished structure. The supplier’s regulatory certificate should be obtained for the specific lot because additive packages and catalyst residues form part of the regulatory assessment. The grade is also covered by the standard REACH registration under Regulation (EC) No 1907/2006; technical data sheets should be consulted for any SVHC content above the reporting threshold.