ExxonMobil Enable mLLDPE 35-05CH is a metallocene-catalysed ethylene-hexene copolymer supplied as pellets for cast film extrusion, lamination film, and heavy-gauge flexible packaging. Typical physical property data place density at 0.935 g/cm³ measured by ASTM D1505, and melt index at 0.5 g/10 min measured by ASTM D1238 at 190 °C and 2.16 kg. The single-site catalyst architecture produces a narrow molecular weight distribution and uniform hexene placement. This molecular uniformity reduces the crystalline heterogeneity found in Ziegler-Natta butene copolymers and lowers the amount of low-melting extractable fractions. In coextruded cast film, the grade is placed in core, skin, or sealant layers requiring stiffness and puncture resistance. The 0.935 g/cm³ density contributes greater modulus and lower moisture vapour transmission than conventional 0.918 g/cm³ LLDPE, while the low melt index preserves melt strength for high-speed web handling.

Because the resin is not a conventional linear-low grade, processing operations must account for changes in shear response, edge stability, and die-deposit behaviour. The specification benchmarks, process limits, and differentiation criteria follow.

What are the primary physical property benchmarks for this metallocene grade?

Representative film property data for ExxonMobil Enable mLLDPE 35-05CH, measured on 25 µm cast film and reported in ExxonMobil technical literature, are summarised below. The values are typical and should not be construed as specification limits.

The dart drop impact of 830 g under ASTM D1709A indicates high toughness for a film of this stiffness. Elmendorf tear values show anisotropic orientation effects typical of cast film; TD tear of 505 g is approximately 1.9 times the MD tear. The haze value of 6.7% and 45° gloss of 70 reflect the surface smoothness achievable when chill roll temperature and air knife conditions are controlled. These optical values degrade when the film is run at low melt temperature or when die lip buildup creates surface defects.

Extrusion behaviour of Enable 35-05CH on cast film lines is controlled by the narrow molecular weight distribution and the 0.935 g/cm³ density. Compared with Ziegler-Natta LLDPE of equivalent melt index, the melt displays less shear thinning, so extruder backpressure and torque can increase at the same screw speed. Barrier screws with an L/D ratio of 30:1 to 36:1, a Maddock mixing section, and screen packs of 120 mesh or finer are used to homogenise the melt. Melt temperature set points between 240 °C and 280 °C are appropriate for many cast lines. Operating above 290 °C increases oxidative degradation, producing gel particles, edge trim discoloration, and odour. Operating below 240 °C can produce unmelted resin, high die pressure, and poor optical clarity. Die gap settings from 0.5 mm to 0.8 mm and an air gap of 60 mm to 100 mm are typical. Chill roll temperatures between 20 °C and 35 °C are used to balance cooling rate, film curl, and roll blocking. Pre-drying of pellets is not required when storage remains below 60% relative humidity; above that threshold, surface moisture can produce splay and transverse streaks in the cast web.

Chill roll surface roughness also affects optical and release properties. Cast rolls with a surface roughness below 0.05 µm Ra and consistent backside water flow produce haze values within the published range. Higher roughness or uneven water flow shifts haze upward and creates non-uniform slip properties. Electrostatic pinning and vacuum box settings must be rebalanced when this grade replaces a lower-density mLLDPE because the narrower molten web and faster crystallisation onset alter the contact point with the chill roll. Failure to reset the pinning system can cause air entrapment and die lines.

Heavy-gauge liners and industrial sacks produced from Enable 35-05CH rely on the combination of 0.935 g/cm³ density and high dart impact. In a typical monolayer cast liner of 100 µm thickness, puncture resistance is dominated by the high tensile strength at break and elongation at break measured under ASTM D882. The film exhibits enough stiffness to run on form-fill-seal equipment without cracking at fold lines. When used as an outer layer in laminated structures, the higher density improves abrasion resistance and reduces curl from adhesive shrinkage during thermal lamination. However, the resin has a lower optical clarity ceiling than lower-density metallocene grades, and converters targeting high-clarity display film must evaluate whether the haze of 6.7% on 25 µm film is acceptable. For demanding deep-freeze packaging, the grade retains dart impact at low temperatures, but specific sub-zero impact data should be generated on the target film gauge because published data for this specific configuration is limited.

Water vapour transmission rate measured by ASTM F1249 on 25 µm cast film decreases with density. The 0.935 g/cm³ resin therefore provides a measurable barrier advantage over a 0.918 g/cm³ LLDPE of similar melt index, but the actual transmission rate depends on film thickness, sealant layer, and chill roll crystallinity. Converters should not estimate barrier values from density alone; testing on the final structure is required for shelf-life models.

When 35-05CH replaces a lower-density mLLDPE in a high-output cast line, which failure modes appear first?

The first process disturbance is usually edge neck-in. The higher density and higher crystallisation onset temperature shorten the molten web and increase neck-in by approximately 5% to 10% relative to a 0.918 g/cm³ metallocene LLDPE. Edge trim width must be increased accordingly to maintain flat-film width. The second disturbance is die lip buildup. Low-molecular-weight oxidised species accumulate on the lip and create die lines, gauge bands, and periodic thickness variation. A fluoropolymer processing aid at 300 ppm to 600 ppm is used to reduce deposit formation and backpressure, but overdosing can produce surging and slip in the screw feed section. The third disturbance is draw resonance. At draw ratios above 15:1, sustained thickness oscillations may appear if melt temperature is too low or air gap is too long. Reducing air gap below 80 mm and increasing melt temperature within the 240 °C to 280 °C window suppress draw resonance. These three failure modes are more severe on high-output cast lines with line speeds above 300 m/min and require closed-loop gauge control.

Film winding and blocking represent additional operational boundaries. Because the resin contains a low extractables fraction, it can exhibit higher surface tack when wound at high tension and roll surface temperatures above 35 °C. Wound roll hardness should be limited to 85 shore C or lower unless anti-block additives are compounded into the skin layer. If the film is used in subsequent adhesive lamination, corona treatment at 38 mN/m to 42 mN/m is typical, but the treatment level decays with time and should be measured before lamination. Values for this specific configuration are not universally published and should be verified on the target converting line.

Differentiation from Ziegler-Natta LLDPE and High-Pressure LDPE in Coextruded Structures

Enable 35-05CH differs from conventional Ziegler-Natta LLDPE primarily in comonomer type and molecular architecture. The hexene comonomer creates longer short-chain branches than butene, improving toughness and tear propagation resistance at comparable density. The metallocene catalyst produces a uniform distribution of hexene across the molecular weight distribution, reducing the high-density, low-melting fractions that can increase seal initiation temperature, extractables, and haze. In coextruded cast film, these differences appear as a wider seal window and less organoleptic contribution. However, the narrow molecular weight distribution of the metallocene resin provides lower melt strength and less shear thinning than autoclave high-pressure LDPE. Blending the mLLDPE with 15 wt% to 25 wt% LDPE is a common practice to improve neck-in, drawdown, and roll geometry without eliminating the stiffness of the 0.935 g/cm³ resin. The blend ratio must be controlled gravimetrically because drift changes both web width and gauge uniformity. Compared with lower-density ExxonMobil Enable grades, such as a 0.918 g/cm³ or 0.927 g/cm³ metallocene LLDPE, 35-05CH provides higher modulus, lower oxygen transmission measured by ASTM D3985, and lower water vapour transmission measured by ASTM F1249. The trade-off is lower low-temperature Dart impact capacity and reduced optical clarity relative to lower-density grades. In blown film, the grade can be processed on low-stalk and high-stalk lines, but bubble stability is less forgiving than LDPE; dual-lip air rings and internal bubble cooling are recommended for stable bubble geometry at high throughput.

For sealant layers, the metallocene structure of 35-05CH enables earlier seal initiation than conventional Ziegler-Natta LLDPE of similar density, but the exact seal initiation temperature is a function of dwell time, jaw design, and film thickness. Published data for this specific configuration is limited, and packaging converters must map the sealing window on the target form-fill-seal machine. For heavy-duty sacks and industrial liners, the resin is typically coextruded with high-pressure LDPE skins or blended with an ethylene-vinyl acetate copolymer to maintain seal integrity at high filling speeds. The melt index of 0.5 g/10 min is intentionally low for the cast film segment, improving melt strength and web stability at the cost of higher extruder pressure and torque. Injection moulding and rotational moulding are outside the intended conversion window because the flow length, clamp force, and cycle time requirements do not align with the low melt index.

Regulatory conformance for food contact and general product safety is summarised below. The status entries should be confirmed against the current product stewardship bulletin because end-use limitations may vary by region.

The resin is not intended for medical implant applications, nor for use in continuous contact with strong oxidising agents or aromatic hydrocarbons. Storage should be in a dry area below 60% relative humidity, away from direct sunlight and ultraviolet sources, with first-in-first-out inventory management. If pellets are exposed to ambient moisture above that limit, drying at 80 °C for 4 h is a conservative starting condition for restoring film clarity and eliminating surface splay; the drying profile must be confirmed on the target dryer.

For converters evaluating this grade against conventional products, the key selection criteria are not solely the melt index and density but the interaction of narrow molecular weight distribution with die design, chill roll finishing, and downstream converting equipment. The product is characterised most reliably on a cast film line with gravimetric feeding and automatic die lip adjustment, because manual gauge correction cannot compensate for the faster crystallisation onset of the 0.935 g/cm³ resin. Published data for some application-specific converting conditions is limited; commissioning protocols should therefore include a trial window that measures gauge variation, neck-in, die deposit formation rate, and film optical response on the target line before committing to commercial inventory.