SABIC LLDPE 119NJ is a butene-based linear low-density polyethylene supplied for general-purpose blown film, lamination film, and carrier bag conversion. The grade is specified at a nominal density of 918 kg/m³ when tested to ISO 1183-1:2019 and a nominal melt flow rate of 1.0 g/10 min at 190°C under a 2.16 kg load when tested to ISO 1133-1:2022. The base formulation contains antioxidant stabilisation and no slip or antiblock additives, allowing converters to control surface friction through masterbatch addition rather than resin selection. Tensile stress at yield is reported as 11 MPa and tensile stress at break as 32 MPa under ISO 527-2:2012; elongation at break exceeds 800%. These values describe compression-moulded test specimens and do not directly represent film performance in the machine and transverse directions.

Standard Property Set Under Producer Test Methods

In blown film conversion, SABIC LLDPE 119NJ is typically processed on single-screw extruders with screw L/D ratios of 24:1 to 30:1 and barrier or Maddock mixing elements. Die gaps of 1.5–2.5 mm are used with blow-up ratios of 2.0:1 to 3.0:1. Melt temperature at the die adapter is maintained between 190°C and 220°C; operation below 180°C increases melt viscosity, raises extruder drive load, and can initiate melt fracture at high take-off speeds. Operation above 230°C accelerates thermo-oxidative degradation and produces gel defects. Frost line height is normally held at 5–7 die diameters. At line speeds above 30 m/min, internal bubble cooling or dual-lip air rings are required to stabilise the bubble and maintain gauge uniformity. Screen packs of 20/40/60 mesh are common, although screen pack selection depends on melt pressure and contamination level in regrind streams.

How Does Butene Comonomer Affect Dart Impact, Tear, and Seal Response?

The butene comonomer in 119NJ produces short-chain branches that reduce crystalline order and set the density at 918 kg/m³. Compared with a hexene-based LLDPE of equivalent melt index and density, the butene-based chain architecture generates a less homogeneous tie-molecule network. This lowers dart impact and machine-direction tear values but improves processability through lower melt viscosity and reduced head pressure. The reported F50 dart impact of 110 g on 30 µm film and the Elmendorf tear ratio of 110/150 kN/m in MD/TD are consistent with a butene-copolymer design. The melting peak at 122°C and Vicat softening point at 95°C establish thermal limits for unstressed and stressed packaging. Heat-seal initiation is observed in the 105–115°C range depending on dwell time and pressure; on 30 µm film, a seal strength of 10 N/15 mm is obtained at 120°C with 0.5 s dwell. Published data for seal strength below 20 µm gauge is limited.

When Down-Gauging from 50 µm to 25 µm in Blown Film

Down-gauging with 119NJ changes the property failure sequence. At 50 µm, converter specifications for dart impact and puncture resistance are typically met without modification. At 25 µm, the F50 dart impact and machine-direction Elmendorf tear decline non-linearly; the producer’s reported 110 g F50 at 30 µm cannot be linearly scaled to lower gauges. Frost line height is reduced by approximately one die diameter to increase quench rate and preserve amorphous tie-molecule fraction. Melt temperature must be held within ±5°C of the 200°C setpoint to avoid bubble oscillation; oscillation above ±3% of neck diameter generates gauge bands that localise tear propagation. When LDPE is added to improve bubble stability, the seal initiation temperature increases and the elongation at break decreases. The exact shift depends on the LDPE grade and blend ratio; published data for this specific configuration in 119NJ is limited and production-line verification is required.

Extrusion Coating and Lamination Equipment Limits

For extrusion coating and lamination, SABIC LLDPE 119NJ is processed through flat dies at melt temperatures of 200–240°C. Die gap settings of 0.4–0.8 mm with chill roll temperatures of 15–25°C are standard for this melt index. Neck-in is higher than in an equivalent autoclave LDPE because 119NJ lacks long-chain branching. Air gap lengths between 100 mm and 150 mm are used to limit surface oxidation while maintaining adhesion to primed paper, aluminium foil, or corona-treated film. Substrate wetting tension should be raised to 40–46 mN/m by corona discharge before coating. At melt temperatures above 240°C, gel formation and pinhole density increase. Draw resonance is less severe than in LDPE at the same melt temperature, but edge bead formation increases with line speed above 100 m/min; deckle adjustment and edge trim removal become necessary.

Compliance documentation for SABIC LLDPE 119NJ is issued by the producer on a grade-specific basis. The resin falls under the olefin polymer provisions of FDA 21 CFR 177.1520 for food-contact articles, subject to end-use extractive limitations. In the European Union, compliance is assessed under EU Regulation No 10/2011 and subsequent amendments, with overall migration limits applied as specified in that regulation. REACH obligations are addressed under Regulation (EC) No 1907/2006; the polymer is exempt from registration as a polymer, but monomer and additive components are covered through supplier documentation. RoHS verification under Directive 2011/65/EU confirms that lead, mercury, cadmium, and hexavalent chromium do not exceed the relevant homogeneous material thresholds. Packaging heavy metal limits are evaluated under EU 94/62/EC.

Comparative Melt Strength and Seal Properties Across Polyethylene Families

Relative to an autoclave LDPE of the same melt index, 119NJ has lower melt strength, lower die swell, and a narrower bubble stability window, but provides improved drawdown and downgauging. The seal initiation temperature is lower than LDPE and HDPE, while the hot-tack plateau is narrower than metallocene plastomers. Compared with HDPE of 945–955 kg/m³ density, 119NJ has lower stiffness and water vapour barrier, but higher low-temperature dart impact and better environmental stress crack resistance. Compared with a hexene or octene metallocene LLDPE of equivalent density and melt index, 119NJ has lower dart impact and tear resistance, lower motor load, and better bubble stability at high take-off speeds. Within the SABIC LLDPE slate, 119NJ is positioned between the lower-MFR 118NJ and the higher-MFR 120NJ; the 1.0 g/10 min melt flow rate gives lower extruder head pressure than 118NJ and higher melt strength than 120NJ. These differences arise from comonomer type and molecular architecture: 119NJ has a linear backbone without the controlled long-chain branching of autoclave LDPE or metallocene elastomers, and a moderately broad molecular weight distribution that stabilises blown film bubble geometry under standard processing conditions.

Incoming quality control for 119NJ typically verifies melt flow rate and density on each lot because these two parameters govern extruder pressure and film gauge response. A melt flow rate outside the ±0.1 g/10 min control band shifts bubble stability and may require screw speed correction. Density variation above ±1 kg/m³ alters seal initiation and stiffness. Moisture content below 0.05 wt% by Karl Fischer titration is recommended before processing to avoid surface splay. Residual catalyst and antioxidant content are not routinely measured by converters, but oxidative induction time by ISO 11357-6:2023 may be used to compare stabiliser batch consistency.

Storage of SABIC LLDPE 119NJ should be maintained below 35°C and out of direct sunlight. At relative humidity above 60%, pre-drying for 2 h at 50–60°C is recommended to prevent moisture-related film defects. Contact with copper or copper alloys should be avoided because copper ions catalyse thermo-oxidative degradation at processing temperatures. The resin should not be blended with flame-retardant halogenated compounds unless adequate stabiliser reloading is performed. Inventory rotation within 6 months is advised to maintain stabiliser activity and avoid yellowing.