Dow ELITE mLLDPE 5960G1 is a solution-polymerised ethylene-1-octene copolymer produced with a constrained-geometry metallocene catalyst. The commercial designation includes mLLDPE to indicate metallocene catalysis, but the nominal density of 0.962 g/cm³, measured by ASTM D792 or ISO 1183-1, places the material in the high-density polyethylene range. Melt flow rate is 1.0 g/10 min at 190°C and 2.16 kg load, determined by ASTM D1238 or ISO 1133-1:2022. The grade is normally supplied as free-flowing pellets without slip or antiblock additives; converters must therefore revalidate the dilution level of any additive masterbatch because the narrow composition distribution can alter additive migration kinetics relative to Ziegler-Natta resins.

• Nominal density: 0.962 g/cm³ (ASTM D792, ISO 1183-1)
• Melt flow rate: 1.0 g/10 min at 190°C/2.16 kg (ASTM D1238, ISO 1133-1:2022)
• Comonomer: 1-octene
• Catalyst class: constrained-geometry metallocene
• Additive package: none specified; masterbatch dilution must be revalidated

Typical blown-film applications include heavy-duty shipping sacks, industrial liners, agricultural silage covers, construction film, vapour barriers, and geomembrane laminates. Film thicknesses of 25–150 µm are common. In vapour-barrier constructions, water vapour transmission rate is normally measured under ASTM F1249 at 37.8°C and 90% RH; in geomembrane laminates, peel adhesion is assessed under ASTM D6392; in industrial liners, puncture resistance is tested under ASTM D5748. The high crystallinity reduces permeability, but the absence of long-chain branching means that processing conditions must be selected with a different bubble-stability window than autoclave LDPE.

From a molecular perspective, the constrained-geometry catalyst permits a narrower short-chain branch distribution than conventional Ziegler-Natta catalysts. The result is a more homogeneous crystalline network, which reduces low-temperature brittle failure. However, the high density and metallocene backbone are not optimised for all conversion routes; in cast-film or injection-moulding operations the narrow molecular-weight distribution can produce higher viscosity at high shear rates and may require rebalancing of melt temperatures.

How does the resin’s architecture differ from conventional high-density film grades?

Gel-permeation chromatography of metallocene high-density resins typically shows a polydispersity index in the range of 2.0–3.5, whereas conventional Ziegler-Natta HDPE film grades often have PDI values between 4.0 and 8.0. The narrower molecular-weight distribution reduces the mass fraction of very low-molecular-weight chains, which can lower hexane extractables and shift environmental stress-crack resistance measured under ASTM D1693, Condition C, toward longer failure times. The comonomer distribution is also more uniform: 1-octene units are incorporated along the backbone with fewer high-crystallinity ethylene-rich segments than in heterogeneous Ziegler-Natta copolymers. This reduces the concentration of large, rigid crystallites that act as stress concentrators under impact loading.

The consequence in blown film is a different balance between dart impact and tear resistance. In conventional HDPE, high density is often achieved by reducing comonomer content, which raises stiffness but can introduce a brittle failure mode when measured by ASTM D1709A. Metallocene incorporation of octene at a density of 0.962 g/cm³ allows the film to retain a higher proportion of tie chains between lamellar stacks. The practical result is that the product typically shows improved dart impact at equivalent secant modulus compared with a Ziegler-Natta HDPE film resin of equivalent density and melt index. However, the improvement is not uniform: on a 90 mm grooved-feed extruder with 30:1 L/D and a 250 mm die, the onset of bubble instability at high haul-off speeds can occur earlier than with autoclave LDPE because the resin lacks the long-chain branching that stabilises strain hardening. Published data for this specific configuration is limited where film thickness exceeds 125 µm.

On a high-throughput blown-film line, barrel temperature setpoints of 180°C to 220°C are sufficient for plastication; adapter and die zones should be maintained below 230°C to suppress oxidative degradation. Die gaps of 1.0–2.5 mm and blow-up ratios of 2.0:1 to 3.0:1 are typical for film thicknesses between 25 µm and 125 µm. Frost-line height is normally held between 600 mm and 900 mm; lower frost lines can produce higher transverse-direction shrinkage, while higher frost lines increase machine-direction orientation and reduce transverse-direction tear strength when measured by ASTM D1922. The resin is less shear-thinning than LDPE because long-chain branches are absent. Therefore, at apparent shear rates above 500 s⁻¹, extruder drive torque can be 15–25% higher than that required for an LDPE resin of the same melt flow rate. Starting conditions for a 120 mm barrier-screw extruder with a 300 mm die should include continuous monitoring of die pressure against the die manufacturer’s pressure rating.

Pre-drying is not normally required because polyethylene moisture absorption is below 0.01 wt% at 23°C and 50% RH. Condensation on cold pellets transferred directly from silo storage at sub-zero temperatures must nevertheless be prevented at the extruder throat to avoid feed-slip and melt-pressure oscillation.

When regulatory compliance boundaries are applied to end-use structures

The base resin may be suitable for food-contact applications under FDA 21 CFR 177.1520, covering olefin polymers for repeated food-contact use, provided that the final article meets extractives limits in that section. For the European market, compliance with EU Regulation No 10/2011 must be demonstrated at the final article level through overall migration testing under EN 1186 and specific migration testing for any additives or colorants. The product does not automatically carry a food-contact declaration in all sales regions; the grade-specific certificate and the supplier’s regulatory information sheet must be checked before use. For potable-water contact, additional testing under NSF/ANSI/CAN 61 may be required. The converter is responsible for verifying the finished structure under the intended conditions of time, temperature and food simulant.

RoHS compliance for electrically related packaging is not a default property of the resin; when used in electronics packaging, the finished article should be assessed against EU Directive 2011/65/EU for lead, cadmium, mercury and hexavalent chromium, with concentration limits of 0.1 wt% for lead and 0.01 wt% for cadmium in homogeneous materials.

Comparative property and processing data matrix

The processing-window comparison below is based on typical published values for film-grade high-density and low-density polyethylenes. Actual line settings depend on die diameter, screw design, air-ring configuration and haul-off speed.

Compared with conventional Ziegler-Natta HDPE film resins of 0.960–0.965 g/cm³ density, 5960G1 has a lower concentration of high-density ethylene-rich crystallites; this typically improves dart impact when tested according to ASTM D1709A at equivalent film thickness. Compared with autoclave LDPE, the product has higher stiffness and lower gas permeability. Oxygen transmission rate measured under ASTM D3985 is typically lower by a factor of 2–4. Compared with standard C8-LLDPE of 0.916–0.920 g/cm³ density, 5960G1 increases tensile modulus under ASTM D882 from the range of 150–350 MPa to approximately 900–1,400 MPa, but reduces elongation at break and tear-initiation resistance under ASTM D1922. The stiffness increase is therefore approximately 4–6× before orientation effects are considered.

Storage at temperatures above 40°C should be limited to 6 months because the stabiliser package is designed for standard warehouse conditions. The base resin does not contain a UV stabiliser; prolonged exposure to sunlight or high-intensity discharge lighting can induce yellowing and loss of mechanical properties. During dry blending with carbon black masterbatch, let-down ratios above 5 wt% can increase melt pressure and reduce bubble stability on lines with die gaps smaller than 1.2 mm. The product should not be combined with pro-oxidant masterbatches or high concentrations of metal stearates intended for degradable films because such additives can accelerate chain scission at processing temperatures above 220°C. In high-humidity environments above 60% RH, pre-drying is not required, but condensate on cold pellets transferred from outdoor silos must be prevented at the extruder throat to avoid feed-slip and melt-pressure oscillation. Maximum recommended melt residence time above 230°C is 15 min before gel formation and crosslinked-particle contamination become detectable.