Asrene LLDPE UF1810 is a linear low-density polyethylene grade manufactured under the Asrene brand and positioned for thin-gauge film end-uses such as heavy-duty sacks, industrial liners, frozen food packaging, and agricultural films. The resin is an ethylene-alpha-olefin copolymer; the precise comonomer type and stabilization package are recorded in the supplier’s certificate of analysis. Asrene LLDPE UF1810 is characterized in consolidated technical literature by a density in the range of 0.917–0.920 g/cm³ when determined by ISO 1183-1:2019, and a melt mass-flow rate of 0.9–1.1 g/10 min when measured under 190 °C and 2.16 kg in accordance with ISO 1133-1:2022. These values place the grade in the medium-molecular-weight, low-density class typical of LLDPE film resins. Films produced from UF1810 are typically evaluated for tensile behavior under ISO 527-3:2018 or ASTM D882-18, for impact resistance under ASTM D1709-16a, and for tear propagation under ASTM D1922-15. The grade is not intended for applications requiring the stiffness or barrier of high-density polyethylene, nor for crosslinked formulations where peroxide or silane grafting response is required.

Typical film constructions incorporating UF1810 include heavy-duty shipping sacks, form-fill-seal pouches for frozen goods, agricultural greenhouse covers, and industrial liners. In these applications, the resin is typically dry-blended with anti-block and slip concentrates at additions of 0.05–0.15 wt% to control blocking and coefficient of friction. The final film is characterized for tensile properties under ISO 527-3:2018, impact resistance under ASTM D1709-16a, tear propagation under ASTM D1922-15, and seal strength under ASTM F88/F88M-21. For agricultural film, UV-stabilizer masterbatch loadings are adjusted according to exposure duration and geographic irradiance; accelerated weathering can be screened by ASTM G154-16, but field validation remains necessary because xenon or fluorescent UV exposure does not reproduce all outdoor thermal-humidity cycles.

Why Is Comonomer Type and Molecular Weight Distribution Critical for UF1810?

In linear low-density polyethylene, comonomer length and short-chain branching distribution control crystalline morphology, density, and toughness. UF1810 is commonly described as a butene-copolymer film resin, but the final comonomer designation must be confirmed against the supplier’s technical datasheet because product formulations can change among production campaigns. The short-chain branches introduced by alpha-olefin incorporation interrupt lamellar growth and reduce density below that of a linear high-density polyethylene. With a density near 0.918 g/cm³ (ISO 1183-1:2019), UF1810 retains enough crystallite content to provide tensile yield stress in the range of 10–12 MPa (ISO 527-2:2012) while allowing elongation beyond 700% in 50 µm blown film (ISO 527-3:2018).

The molecular weight distribution governs processability and bubble stability. A grade with melt index near 1.0 g/10 min (ISO 1133-1:2022) has sufficient melt viscosity for blown film bubble retention, but linear chains exhibit less shear thinning than long-branched LDPE. Consequently, melt pressure and motor load respond differently to screw speed changes. Data are limited for grade-specific GPC curves, but the melt flow ratio and comonomer sequence distribution can be obtained from the manufacturer when optimization of heat-seal performance is required. In downgauged films, the interaction between comonomer distribution and crystalline orientation after the frost line determines the balance of dart impact and machine-direction tear; processors using UF1810 should therefore not infer performance from density alone.

Blown film lines running UF1810 commonly use grooved feed extruders with length-to-diameter ratios of 30:1 to 33:1 and barrier screws having compression ratios around 2.5:1 to 3.0:1. The resin is melted and homogenized at a flat-to-slightly reverse barrel profile from 180 °C in the feed zone to 220 °C at the die head, with die temperature not exceeding 230 °C to limit odor and degradation. A die gap of 1.5–2.5 mm and a blow-up ratio of 2.0:1–3.0:1 are standard starting conditions. The frost line height is normally set at 2.0–3.0 die diameters; lower frost lines increase film clarity but reduce bubble stability in LLDPE.

In cast film extrusion, UF1810 is processed through a slot die with a die gap of 0.5–0.8 mm, a chill roll temperature of 20–30 °C, and melt temperatures from 220 °C to 240 °C. The linear polymer’s narrower molecular weight distribution yields lower die swell than LDPE, so edge bead and melt curtain stability respond to die gap changes more directly. On production lines, the most common failure modes are bubble oscillation in blown film and melt curtain sag in cast film; both are corrected by modifying air ring or vacuum box settings rather than by increasing melt temperature alone.

Typical Resin Characteristics and Test Method Cross-Reference

Published data for UF1810 are limited in consolidated form, and the values shown below are representative ranges reported for LLDPE film grades of this density and melt index rather than a certified product specification. Each lot should be verified against the supplier’s certificate of analysis.

Mechanical properties are method-dependent. ASTM D638-14 and ISO 527-2:2012 report tensile values for compression-molded specimens, while ISO 527-3:2018 and ASTM D882-18 use film specimens. Dart impact values under ASTM D1709-16a vary with film thickness, frost line height, and blow-up ratio; the 80–100 g range is typical for 25 µm film. Haze and gloss measured under ASTM D1003-13 and ASTM D2457-13 are strongly affected by melt temperature and die design. The Vicat softening temperature under ISO 306:2022 is 90–95 °C, which remains below the melt peak measured by ISO 11357-3:2018.

UF1810 differs from conventional autoclave or tubular low-density polyethylene in its branching architecture. LDPE contains long-chain branches that increase melt strength and shear thinning; UF1810 is linear and lacks significant long-chain branching. Under ASTM D1709-16a, UF1810 films at 25 µm generally exhibit higher dart impact values than an LDPE film of equal thickness, but haze and gloss may be less favorable. Seal strength at low temperature is also higher because LLDPE melting distribution contains more low-temperature crystallites, but the actual seal initiation temperature requires measurement under ASTM F2029-16.

Compared with octene-based LLDPE grades of equivalent density and melt index, UF1810—if it is a butene-copolymer grade—has lower dart impact and lower Elmendorf tear, especially in downgauged structures. This difference arises because octene short-chain branches are more effective at tying separate crystalline lamellae. Compared with HDPE, UF1810 has lower density, lower flexural modulus, higher strain at break, and lower water-vapor barrier; these differences are routinely captured by ISO 178:2019, ISO 527-2:2012, and ASTM E96/E96M-22a.

When UF1810 Is Substituted for Low-Density Polyethylene in High-Strength Film

Substitution of UF1810 for LDPE on an existing blown film line requires adjustment of the thermal profile and die geometry. The barrel temperatures in the compression and metering zones are raised by 10–20 °C to compensate for the lower shear sensitivity of linear polyethylene. The die temperature is maintained at 220–230 °C. Because LLDPE has a steeper viscosity-temperature response, the melt pressure may remain 10%–20% higher than LDPE at the same screw speed. Motor load is monitored against the extruder drive limit; if load exceeds 90% of rated torque, screw speed must be reduced or a wider die gap selected.

Bubble stability decreases because UF1810 has lower extensional viscosity and lower melt strength than LDPE. A dual-lip air ring with adjustable lower-lip flow and a suitable internal bubble cooling system is standard when blow-up ratio exceeds 2.5:1. The frost line height is typically increased to 2.5–3.5 die diameters to stabilize the bubble. Heat-seal temperatures on converted pouches may be reduced by 15–25 °C relative to LDPE, depending on film thickness and seal dwell time. Published data for UF1810-specific heat-seal curves is limited, so seal temperature reduction should be validated on the converting line.

Die Pressure, Motor Load, and Air Ring Requirements

Die pressure in UF1810 film extrusion is a combined function of melt viscosity, die gap, and output. On a 90 mm grooved feed extruder with a 300 mm die, die pressure typically falls between 250 and 400 bar at outputs of 150–250 kg/h, but line-specific data should be used. Pressures above 450 bar indicate excessive head pressure and are associated with screen pack blinding, insufficient die temperature, or too narrow a die gap. Motor load is similarly sensitive to back pressure; the extruder should be operated below the rated drive limit, with a margin of 10%–15% to accommodate feed throat bridging or screen pack pressure rise.

Air ring requirements are more sensitive for UF1810 than for LDPE because the linear chains do not strain-harden to the same extent at high take-off speeds. The lower lip air velocity should be set high enough to produce a stable bubble neck but not so high that the frost line moves below 1.5 die diameters, which can create gauge bands and poor optical quality. Melt fracture, particularly sharkskin at the die lip, is controlled by increasing die temperature 5–10 °C, widening the die gap by 0.2 mm, or adding a processing aid at the lowest effective concentration.

For food-contact evaluations, UF1810 should be assessed against FDA 21 CFR 177.1520 for olefin polymers; the resin must meet the specified density and extractable fraction criteria when monolayers are intended for direct food contact. In the European Union, migration testing follows Regulation (EU) No 10/2011, and the overall migration limit is 10 mg/dm² under the required food simulant conditions. REACH registration is maintained by the manufacturer; converters should confirm the registration number and any SVHC status from the safety data sheet. RoHS screening for lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE is generally not product-limiting for unfilled polyethylene resins, but certification should be requested if the final article falls within electrical and electronic equipment scope.

Pre-drying is not required at ambient relative humidity below 60%. Above that threshold, surface moisture can produce splay, bubble defects, or edge voids during extrusion. The resin should not be dry-blended with amine-containing or highly unsaturated additives without evaluating the interaction with the stabilization package, because such combinations can shift oxidation induction time and heat-seal color. UF1810 is not designed for peroxide-crosslinked polyethylene processing or for silane-grafting processes that require a high vinyl content, because the molecular architecture and antioxidant package may not support the required grafting kinetics. Published data for UF1810 in multilayer coextrusion with polyamide or EVOH are limited; tie-layer selection should be based on peel strength measurements under ASTM F88/F88M-21 and cycle testing of the final structure.