The product designation SABIC LLDPE 120NT identifies a linear low density polyethylene resin supplied by SABIC as pelletised feedstock for blown-film extrusion. The polymer is an ethylene-alpha-olefin copolymer with a nominal melt flow rate of 1.0 g/10 min measured under 190°C and 2.16 kg load in accordance with ASTM D1238/ISO 1133, and a nominal density of 0.920 g/cm³ determined by ASTM D1505/ISO 1183 at 23°C. The material falls under the linear low density polyethylene classification in ASTM D883 terminology because the density is below 0.940 g/cm³. These numerical values are supplier-reported nominal data points, not specification limits, and the approved range for each production lot appears on the certificate of analysis.

Within the SABIC film portfolio, the grade is positioned for general-purpose packaging applications that include heavy-duty sacks, industrial liners, lamination films, and overwrap structures. The balance of density and melt flow rate provides a combination of puncture resistance and processability on conventional blown-film lines; however, the specific performance achieved by a converter depends on die geometry, frost-line height, blow-up ratio, and cooling-air configuration. The resin is not a direct drop-in substitute for every LLDPE or LDPE grade, because the molecular architecture and additive package affect extrusion pressure, melt stability, film optics, and sealing behaviour.

Before production use, the converter should obtain the current SABIC technical data sheet for lot-specific values and regulatory statements. Publicly available third-party databases may list typical mechanical and optical values, but additive packages and manufacturing-site variations can shift results. Film property measurements are meaningful only when the test standard and specimen preparation are reported alongside the value; a tensile or tear number without ASTM D618 conditioning and orientation direction cannot be compared across resin grades.

What processing boundaries apply when 120NT replaces a 0.923-density LLDPE film resin?

Replacement of a higher-density film resin with 120NT on an existing blown-film line usually changes the bubble geometry required for stable operation. The lower density and short-chain branch content alter the crystallisation rate, making the frost-line position less tolerant of high cooling-air turbulence. Processors frequently observe bubble instability when the blow-up ratio exceeds 3.0:1 or falls below 1.8:1; the failure appears as sagging, breathing, or oscillation before the film enters the primary nip. These boundaries are not absolute but are observed on single-screw blown-film towers with die diameters between 150 mm and 350 mm at melt temperatures near 200°C.

Die gap selection is another process variable that differentiates 120NT from LDPE formulations. A die gap of 1.5 mm to 2.2 mm is generally preferred for LLDPE film grades to limit melt fracture and maintain film optical uniformity. Wider gaps, such as 2.8 mm to 3.2 mm used for high-melt-strength LDPE, may increase residence time and promote oxidation in the die lip region. On lines with fixed die gaps above 2.5 mm, the converter may compensate by raising die set temperature to 210–220°C or reducing throughput by 5–15%; however, the resulting film may show hazier sections as measured by ASTM D1003.

The upper melt temperature limit for 120NT is governed by the antioxidant package and potential thermo-oxidative chain scission, not by the melting point alone. At die set temperatures above 230°C, LLDPE films can develop gel-like particles from degraded antioxidant clusters and local crosslinking, which are then visible in the final film as fisheyes. For this reason, barrel profiles in the feed section should remain near 170–180°C and increase gradually to the die. Excessive specific energy input from a worn screw or high screw speed can also produce melt temperatures above the set point; measurement with an infrared melt thermometer is advised on extrusion lines exceeding 150 kg/h throughput.

Film lines without internal bubble cooling rely on single-venturi air rings and frost-line height to remove heat. At high throughput, the lower crystallisation rate of 120NT relative to a 0.926 g/cm³ LLDPE can move the frost line upward if the air-ring airflow remains unchanged. The shift appears as a less distinct frost-line boundary and may reduce transverse-direction tear because the longitudinal orientation increases. Processors with adjustable air rings typically respond by increasing cooling-air volume by 10–20% or reducing melt temperature by 5–10°C, but these adjustments must be validated with film gauge, haze, and tear data.

Standard Physical Properties and Specification Boundaries

The table below lists the two most commonly cited specification values for SABIC LLDPE 120NT alongside a general-purpose LDPE film reference range. The LLDPE values are nominal supplier-reported data; the LDPE range is a general market reference and does not represent a specific commercial grade. In film-grade comparisons, melt flow rate and density are insufficient to predict dart impact, tear strength, heat-seal response, or optical quality; those properties must be measured on the target film line.

Additional mechanical values for 120NT—such as machine-direction tensile strength at break, transverse-direction elongation, dart impact F50, Elmendorf tear, and haze—are not uniform across open technical databases. Where missing from a publicly available data sheet, they should be obtained from the SABIC certificate of analysis or from a laboratory evaluation on the converter’s own blown-film line. A limited dataset generated on a 40 mm laboratory extruder with a 2.0 mm die gap may not reproduce the properties of a production-scale 90 mm extruder with high throughput and internal bubble cooling.

In heavy-duty sack applications, film converted from SABIC LLDPE 120NT is evaluated against dart impact resistance per ASTM D1709 and tear propagation resistance per ASTM D1922. The package must withstand repeated handling drops and abrasive contact; therefore the film is usually specified at 60–125 μm thickness rather than by any single mechanical value. Because LLDPE grades with 0.920 g/cm³ density provide a higher ductile-brittle transition margin than higher-density LLDPE, converters often select 120NT for cold-climate shipment packaging where polyethylene becomes stiffer at low temperatures. The degree of low-temperature improvement should be verified by dart impact testing at 0°C or -10°C, not assumed from ambient-temperature data.

For lamination films and coextruded structures, 120NT may serve as the core or strength layer. The material is combined with metallocene-catalysed LLDPE skin layers for seal performance and with LDPE layers for bubble stability. Seal strength of the finished structure is measured according to ASTM F88, and hot-tack performance is measured according to ASTM F1921. The use of 120NT in the core layer adds puncture resistance to the laminate, but the converter must ensure melt viscosity matching between layers to prevent interfacial instability. The layer ratio, melt temperature set point, and die adapter geometry are determined by coextrusion flow simulation; published data for this specific configuration is limited.

When the grade is compared with LDPE, metallocene LLDPE, and higher-density LLDPE

Compared with a high-pressure LDPE of similar melt flow rate, SABIC LLDPE 120NT shows a higher concentration of linear chains and short-chain branches, which influences solid-state and melt behaviour without increasing density. The crystalline regions are thinner and more numerous, producing films with higher elongation at break and greater resistance to slow puncture. In comparative tests, LLDPE films often show higher dart impact and Elmendorf tear than LDPE films at equal thickness, provided the test specimens are prepared with equivalent frost-line orientation and blow-up ratio. The measurement standards for these comparisons are ASTM D1709 for dart impact and ASTM D1922 for tear strength; the actual numerical difference depends on film thickness, temperature, and additive package.

Relative to metallocene-catalysed LLDPE, the 120NT grade—like many conventional Ziegler-Natta LLDPE films—tends to exhibit a broader molecular weight distribution and a more heterogeneous comonomer distribution. The broader distribution generally improves extrusion processability at a given melt index, reducing melt fracture and allowing wider die gaps. The trade-off is typically higher haze as measured by ASTM D1003, lower gloss as measured by ASTM D2457, and a higher seal initiation temperature as measured by ASTM F88. A converter seeking high clarity and fast sealing may prefer a metallocene grade; a converter needing stable bubble formation and lower backpressure may retain 120NT. This trade-off should be evaluated with full film specifications, not with melt index alone.

Against a higher-density LLDPE such as a 0.926 g/cm³ grade, 120NT generally offers lower flexural modulus as measured by ASTM D790 and higher dart impact. It is therefore preferred for flexible packaging where conformability and puncture resistance matter more than stiffness. A higher-density LLDPE is preferred for stand-up pouches or heavy-duty can liners where the film must resist tensile deformation under load. The selection is not a quality distinction but a density-dependent balance between stiffness and impact; the processing conditions on the target line determine whether the chosen grade yields the required gauge-uniformity profile.

Film properties such as static coefficient of friction and blocking are not intrinsic to the base resin; they are controlled by migratory slip agents and mineral antiblock packages. The 120NT grade may be supplied with or without additive packs, and the converter must specify the required coefficient of friction range measured by ASTM D1894 and blocking force measured by ASTM D3354. Differences from other products therefore include not only molecular architecture but also additive loading and thermal history.

Regulatory Documentation Is Only Valid When Converters Confirm Food-Contact Statements

Polyethylene grades intended for food contact require documentary evidence of compliance that is specific to the manufacturing site, the production line, and the additive package. The table lists the principal regulatory texts cited for SABIC LLDPE 120NT in packaging applications. The presence of the grade on a supplier’s positive list does not automatically clear the final film; the converter is responsible for verifying that the finished article meets the overall migration limit and any organoleptic requirements.

For agricultural silage film, the LLDPE layer produced from 120NT is exposed to ultraviolet radiation, silage acids, and mechanical stretching during wrapping. Evaluation of this film requires not only mechanical testing but also resistance to environmental stress cracking after exposure to a nonionic surfactant solution according to ASTM D1693. Published data for 120NT in prolonged outdoor service is limited; field trials on the converter’s target wrapping machinery are required to establish a performance envelope.

Film scrap generated during start-up and edge trimming of 120NT can be recycled back into the extrusion line, provided the regrind is free of paper labels, moisture, and incompatible polymers. The addition of regrind above 30% by weight may alter film haze and dart impact, particularly if the scrap has undergone multiple heat histories. On a production line with automatic die-lip adjustment, the thickness profile can be kept within ±5%, but gauge variation near the edges may still occur during changes in blow-up ratio. The use of 120NT in such closed-loop recycling operations requires measurement of melt flow rate stability by ASTM D1238 and density by ASTM D1505 after each heat cycle to detect crosslinking or chain scission before film properties fall outside the converter’s specification.