SABIC LLDPE 202NT is a butene-1 linear low-density polyethylene supplied in natural pellet form. The grade is produced for blown film and cast film conversion, with typical uses in carrier bags, agricultural film, overwrap, and lamination webs. The nominal density is 0.920 g/cm³ when measured according to ISO 1183-1:2019, and the nominal melt flow rate is 2.0 g/10 min at 190 °C/2.16 kg under ISO 1133-1:2022. These two values establish the primary specification boundary: density controls film stiffness, permeability, and seal initiation, while melt flow rate controls shear viscosity, extruder head pressure, and drawdown. The suffix in the grade code is not defined as a resin chemistry descriptor in every regional document; the product should be sourced against the manufacturer’s current sales specification and lot certificate of analysis. The typical values in this introduction are not batch-release limits.

The comonomer is butene-1, which generates ethyl side groups in the polymer backbone. In contrast, hexene-based LLDPE contains butyl side groups. At a fixed density of 0.920 g/cm³, the C4 copolymer requires more molar comonomer than a C6 copolymer because ethyl branches are less effective at disrupting the crystal lattice. This leads to a broader short-chain branch distribution, a wider melting endotherm, and a lower concentration of tie molecules connecting lamellar crystals. The tie-molecule reduction lowers dart puncture resistance, while the broader distribution improves processability by broadening the relaxation spectrum. The balance is measurable by ISO 7765-1:2004 dart drop and ISO 6383-2:1983 Elmendorf tear. These differences become more pronounced as film thickness falls below 25 µm.

Table 1 reports representative values from public grade literature for compression-moulded plaques and 25 µm blown film conditioned for 24 h under ISO 187:2016 at 23 °C/50% RH. Film specimens were produced at a 2.5:1 blow-up ratio, a 2.0 mm die gap, and a 200 °C melt temperature. Changing these parameters will move the tear and impact values.

The tensile strain at break above 800% is a low-strain-rate ductility indicator and does not translate directly to high-speed film toughness. The dart drop value of 110 g is the 50% failure energy for 25 µm film and is lower than the value expected from a C6 or metallocene LLDPE of identical density and melt flow rate. Haze near 15% and gloss near 60 under 60° with ASTM D2457 place the product in the general-purpose film segment. These optical values are sensitive to die-gap upset and frost line height because surface roughness from melt fracture increases haze without changing bulk crystallinity.

What Blown Film Extrusion Parameters Match a 2.0 g/10 min Butene-LLDPE?

On blown film lines using grooved-feed single-screw extruders with 25:1 to 30:1 L/D and screw diameters from 40 mm to 90 mm, adapter melt temperatures are maintained between 190 °C and 220 °C. Die gaps of 1.5 mm to 2.5 mm are used for final thicknesses from 15 µm to 80 µm. A blow-up ratio of 2.2:1 to 3.5:1 and a frost line height of 150 mm to 300 mm above the die are common starting points. The controlling process conflict is bubble instability rather than extruder head pressure: a 2.0 g/10 min butene grade has lower zero-shear viscosity and melt tension than a 1.0 g/10 min grade, so large-bubble operation may become unstable at high output. On a 90 mm die with a 2.0 mm gap, output above 120 kg/h can produce bubble oscillation unless internal bubble cooling or higher tower height is available. These values are drawn from production-scale equipment behavior and should be treated as starting points rather than absolute limits.

Shear viscosity of SABIC LLDPE 202NT follows the shear-thinning behavior of broad-molecular-weight-distribution Ziegler-Natta LLDPE. At 190 °C, the apparent viscosity at 100 s⁻¹ is reduced relative to a 1.0 g/10 min C4 grade, lowering motor load and melt temperature rise. The same reduction in viscosity reduces melt tension and makes the bubble more sensitive to cooling-air fluctuations. Melt fracture is controlled by die-lip shear stress; if the die gap is narrowed below 1.0 mm while attempting to improve gauge uniformity, surface sharkskin may appear before melt pressure limits are reached. Published capillary viscosity curves for this exact grade are limited; die-design work should use measured rheology rather than the single-point melt flow rate.

In cast film extrusion, melt temperature can be raised to 220 °C to 240 °C at the die because the quench roll solidifies the web before oxidative discoloration becomes severe. Chill roll temperatures of 20 °C to 40 °C are used to control blocking and maintain film flatness. The MFR of 2.0 g/10 min provides higher drawdown than 1.0 g/10 min grades and reduces neck-in relative to 3.5 g/10 min cast-film grades. Line speeds above 150 m/min may be limited by pinning stability when the die gap is below 0.7 mm; a wider gap and higher air-knife velocity are preferred under those conditions.

When SABIC LLDPE 202NT Replaces LDPE in Blown Film Structures

Replacing LDPE with SABIC LLDPE 202NT changes the melt-strength and heat-seal balance. The LLDPE has lower elongational viscosity, so the frost line is usually lowered or the blow-up ratio is reduced until bubble stability is restored. The heat seal initiation temperature of a butene LLDPE at 0.920 g/cm³ is typically 10 °C to 15 °C lower than that of LDPE, measured by heat seal tests according to ASTM F2029-16. The lower seal initiation can reduce jaw energy but narrows the hot-tack window. Blends with 20% to 30% LDPE are used in heavy-duty sacks and carrier bags to increase melt strength and bubble stability. The LDPE addition raises haze by 2 to 5 percentage points and lowers dart drop by 10% to 15% compared with the unblended film. These magnitudes are process-dependent and should be verified on the target line because they shift with die gap and frost line height.

Compared with a Ziegler-Natta C6 LLDPE of equal density and melt flow rate, SABIC LLDPE 202NT has a broader short-chain branch distribution, lower tie-chain concentration, and lower dart puncture resistance. Its processing advantage is lower melt pressure and stronger shear thinning on older extruders with limited screw-speed capability. Compared with a metallocene-catalyzed C6 grade, the butene grade has wider molecular weight distribution, better melt fracture resistance, but lower film clarity, lower puncture resistance, and less favorable machine-direction/transverse-direction tear balance. The selection boundary is therefore functional: SABIC LLDPE 202NT is used where processing ease and cost per kilogram outweigh optical and puncture requirements. Published data for direct comparative runs between SABIC LLDPE 202NT and specific metallocene grades are limited; converter trials remain the most reliable comparison method.

In carrier bag production on downstream converting lines, the film is folded and sealed through bottom-seal or side-seal equipment. The low heat seal initiation temperature of the butene LLDPE permits higher seal-bar cycling rates, but the film also shows lower hot tack than EVA or ionomer sealants. For heavy-duty sack coextrusion, SABIC LLDPE 202NT is typically employed in the core or skin layer at thicknesses from 8 µm to 20 µm per layer; the LDPE or C4 skin provides melt strength and seal response. Blown film lines producing agricultural tunnel film use ultraviolet stabilization packages added by the converter. The base resin has no UV stabilizer unless specified in the lot documentation. Additive interaction with hindered-amine light stabilizers should be checked because acidic or sulfur-containing additives can interfere with the stabilizer package under long outdoor exposure.

Heat-seal performance is influenced by density and comonomer type. At 0.920 g/cm³, the seal initiation temperature is lower than that of 0.925 g/cm³ LDPE and higher than that of 0.915 g/cm³ plastomer. The sealing range of SABIC LLDPE 202NT is therefore positioned for packaging lines that require low seal-bar temperature but do not use high-speed vertical form-fill-seal machinery with very short dwell times. Hot-tack strength can be tested by ASTM F1921-12; published data for this grade are limited.

The optical haze value near 15% is controlled by surface roughness and internal light scattering from spherulites. Surface roughness is influenced by die-gap exit stress; if the frost line is too low, the surface freezes before relaxation, preserving die-lip melt fracture patterns. Raising the melt temperature to 220 °C lowers die-lip stress and improves gloss but increases oxidation risk. The antioxidant package is consumed during processing and later during film service. The induction time measured by ISO 11357-6 oxidative OIT is a useful lot-level check for incoming resin. A significant reduction in oxidative induction time indicates antioxidant depletion or contamination with pro-oxidant metal ions from conveying equipment. The manufacturer does not publish a guaranteed OIT for this grade in all regions; converters with long-term outdoor film exposure should specify this test in the purchase specification.

Regulatory Status, Storage Boundaries, and Additive Compatibility

The olefin polymer base is of the type described in FDA 21 CFR 177.1520 for food-contact olefin polymers. End-use migration testing remains the converter’s responsibility, particularly for fatty or high-temperature food contact. In the European Union, compliance with Regulation (EU) 10/2011 requires overall migration and specific migration testing under the intended food simulant conditions. For electrical and electronic equipment, homogeneous materials are evaluated under Directive 2011/65/EU RoHS; the relevant limits are 100 mg/kg for cadmium and 1000 mg/kg for lead, mercury, and hexavalent chromium. The bulk polymer is not intentionally formulated with these metals, but lot certificates should be reviewed when post-consumer recyclate is used. Polyethylene does not require drying in dry indoor storage. If bags are stored at RH > 60%, surface condensation must be removed by pre-drying at 70 °C for 1 h to 2 h before extrusion. Melt temperatures above 230 °C should be avoided because antioxidant consumption accelerates and gel defects can appear in thin film. Amine-based nitroxide radical traps should not be combined with the grade unless validated, because of potential antagonism with the phenolic stabilizer under oxidative processing.

SABIC LLDPE 202NT is limited to blown film and cast film conversion; it is not formulated for injection molding, rotational molding, or pipe extrusion. The nominal melt flow rate of 2.0 g/10 min is sufficient for thin-gauge drawdown while retaining film toughness in the 15 µm to 80 µm range. Before sustained production, the converter should verify lot-specific melt flow rate, density, additive package, and food-contact documentation against the manufacturer’s sales specification.