SABIC LLDPE MG500026 is a metallocene-catalysed linear low-density polyethylene supplied as pelletised resin for monolayer and multilayer film conversion. The grade is characterised by a nominal density of 0.918 g/cm³ under ISO 1183-1:2019 and a melt flow rate of 2.6 g/10 min under ISO 1133-1:2022 at 190 °C/2.16 kg. Hexene is used as the primary comonomer, and the narrow molecular weight distribution provides a specific balance between optical clarity, seal initiation, and dart impact resistance that differs from conventional butene-based Ziegler-Natta LLDPE. The product is intended for blown film lines producing food packaging, stretch hood, heavy-duty sacks, and laminated film structures where melt homogeneity and low gel levels are required.

What Limits the Blown Film Processing Window for MG500026?

The melt rheology of MG500026 imposes a practical processing envelope on high-output film lines. The shear viscosity at 230 °C and 100 s⁻¹ is lower than that of a Ziegler-Natta LLDPE of equal density and melt index, which reduces extruder torque but also lowers melt strength. On a 60 mm grooved-feed extruder with 30:1 L/D, melt temperatures between 190 °C and 240 °C are typical; die temperatures above 250 °C increase the risk of gel formation and should be avoided. The bubble is normally stable at blow-up ratios from 2.0:1 to 3.0:1; at blow-up ratios above 3.2:1, bubble instability and film gauge variability are observed unless the resin is blended with a high-melt-strength LDPE. The recommended die gap is 1.8 mm to 2.5 mm for film thicknesses from 25 µm to 120 µm.

The melt temperature window is also limited by antioxidant package efficiency. At 260 °C, the oxidation induction time measured by ISO 11357-6:2018 declines sharply; prolonged residence times above 240 °C can generate cross-linked gel particles visible as 0.2 mm to 0.5 mm specks in thin film. A flat temperature profile from rear to front zone with a maximum 10 °C rise before the die is used to prevent shear-induced molecular degradation. The die pressure on a 60 mm extruder producing 100 µm film at 200 kg/h typically ranges from 280 bar to 360 bar; values above 400 bar indicate insufficient die gap or excessive melt viscosity, and the screen pack should be inspected for partial blockage.

These values are nominal and should be confirmed against lot-specific certificates of analysis. Published data for this specific configuration is limited for cast film; extrusion trials should map melt pressure and bubble stability against line speed.

The screw design should use a barrier flight and a distributive mixing section with moderate shear input. Grooved feed sections are preferred because the low bulk density of LLDPE can otherwise limit throughput. The specific output on a 60 mm grooved-feed extruder at 210 °C typically falls between 0.12 kg/h·rpm and 0.16 kg/h·rpm; however, published data for this specific configuration is limited, and line output is strongly influenced by die head pressure and gear pump performance. When switching from LDPE, the extruder should be purged with a low-MFR LLDPE or the same grade with the die temperature raised by 10 °C to remove high-molecular-weight residues. No predrying is normally required; if condensation is observed after storage at relative humidity above 60%, a 2 h air purge at 65 °C is sufficient.

Hexene Comonomer Distribution Lowers Seal Initiation in Multilayer Sealant Layers

In sealant layers of three-layer coextruded film, MG500026 exhibits a lower seal initiation temperature than butene-based Ziegler-Natta LLDPE of similar density. The difference is typically 8 K to 12 K when measured by a laboratory heat sealer at 0.4 MPa seal pressure and 0.5 s dwell time on 50 µm cast film; this shift is attributed to more uniform interchain crystallinity and a narrower melting range. Hot tack curves show a steeper increase after 90 °C, allowing faster jaw cycling on vertical form-fill-seal machines. However, the lower melt strength of the metallocene resin can reduce bubble stability in the sealing layer when run as a 70% or higher blend. In such structures, a high-pressure LDPE addition of 10% to 20% is used to restore bubble stability without reversing the seal initiation gain.

The seal strength plateau is influenced by heat-seal jaw temperature and dwell time. At 110 °C with 0.5 s dwell on 50 µm film, seal strength reaches 8 N/15 mm to 12 N/15 mm under ASTM F88/F88M-21; at 95 °C, seal strength remains below 4 N/15 mm, which defines the lower seal limit for high-speed packaging. The hexene comonomer reduces the crystalline melting point to 122 °C by ISO 11357-3:2018, which contributes to lower seal initiation. Migration of slip additives from the sealant layer follows Fickian diffusion; at 40 °C, erucamide surface bloom reaches a stable coefficient of friction after 24 h to 72 h, depending on film crystallinity and additive loading. No amine-based processing additives should be combined with the resin because they alter seal performance and can generate odour at melt temperatures above 220 °C.

Food-contact status for MG500026 is established through supplier certification against FDA 21 CFR 177.1520 and EU 10/2011. The grade is manufactured to meet the overall migration limit of 10 mg/dm² under EN 1186-1:2002 test conditions for aqueous and fatty food simulants, provided the converted film is not subjected to post-processing conditions outside the supplier’s specified temperature range. The resin does not contain antimony trioxide, halogenated flame retardants, or heavy metals above 100 mg/kg for the sum of lead, cadmium, mercury, and chromium(VI) when assessed under EU 94/62/EC and CONEG model legislation. REACH SVHC content is below the 0.1% w/w reporting threshold; this statement is based on supplier declaration and should be verified per lot for imported packaging where EU compliance is mandatory.

When MG500026 Replaces Ziegler-Natta LLDPE in Blown Film Lines

A direct drop-in replacement on an existing Ziegler-Natta LLDPE line is not always possible without parameter adjustment. Because the metallocene resin has a narrower molecular weight distribution, shear viscosity at the die lip is lower, which reduces melt fracture and permits higher screw speeds before sharkskin appears. At the same time, the lower melt strength requires a reduction in the freeze-line height or blow-up ratio by 10% to 15% to maintain gauge uniformity. Comparative data on 50 µm monolayer blown film show that dart drop impact increases by 20% to 35% over a butene-based Ziegler-Natta LLDPE of equal density, while haze is reduced by approximately 3 to 5 percentage points. The trade-off is a higher tendency for melt resonance at high draw-down ratios in cast film; published data for this specific configuration is limited for cast film above 300 m/min line speed.

In cast film, the absence of bubble support makes the lower melt strength of MG500026 more apparent. Draw resonance begins at lower draw ratios than for a Ziegler-Natta LLDPE of similar density; line speeds above 300 m/min require a chill-roll temperature below 25 °C and an air gap below 10 cm to maintain thickness uniformity. The narrower molecular weight distribution reduces melt fracture and permits higher throughput before surface roughness appears. Switching from a butene-based Ziegler-Natta LLDPE also reduces film-blocking tendency and lowers the concentration of low-molecular-weight extractable material, which is relevant for food contact and pharmaceutical packaging where migration criteria are strict.

MG500026 is not formulated for applications requiring high melt strength, such as large-part blow moulding, pipe, or rotomoulding. Blown film processing above 280 °C is outside the recommended operating window and can deplete the phenolic stabiliser system, producing yellowing and gel specks. The resin should not be stored in direct sunlight for extended periods, as UV exposure can reduce antioxidant reserves and increase the carbonyl index; warehouse storage at 25 °C and 50% relative humidity is adequate. High levels of recycled trim exceeding 30% by weight may introduce gel contamination and reduce dart impact, particularly in thin-gauge sealant layers. The product is incompatible with amine-based antifogging additives at high addition levels when film is stored above 40 °C, because amine migration can accelerate phenolic antioxidant depletion and shift seal initiation temperatures upward.

Stretch Hood and Heavy-Duty Sack Extrusion Parameters

For stretch hood film in the 80 µm to 120 µm thickness range, MG500026 is processed on three-layer lines with a die gap of 2.0 mm to 2.4 mm and a blow-up ratio of 2.8:1 to 3.2:1. The gauge profile is controlled with an air ring and internal bubble cooling; external cooling air temperatures of 10 °C to 15 °C improve mechanical toughness by lowering the quench rate. Slip and antiblock additives are required because the neat resin has a high blocking tendency above 30 °C. Typical letdown additions are 5% to 8% of a silica-based antiblock masterbatch and 2% to 3% of a slip masterbatch containing 5% erucamide; the resulting coefficient of friction is typically 0.20 to 0.30 after 72 h at 23 °C. Heavy-duty sacks produced at 100 µm to 150 µm benefit from the higher dart impact of MG500026, but the lower melt strength may require a 20% LDPE blend to maintain bubble stability at high output rates.

Compared with SABIC LLDPE 118WJ or 218WJ, which are conventional butene-based Ziegler-Natta grades, MG500026 provides lower seal initiation temperature and lower haze at equivalent density. However, the metallocene grade is more sensitive to shear heating and requires tighter control of extruder barrel temperatures; uncontrolled shear heating in a 30:1 L/D barrier screw can raise melt temperature above 250 °C even when the setpoint is 220 °C. Compared with LDPE grades of similar melt index, MG500026 has lower melt strength and should not be used as the sole resin in high-stalk bubble configurations. The difference in comonomer type and distribution also reduces the amount of low-molecular-weight extractable material; this is relevant for food contact and pharmaceutical packaging where migration criteria are strict.