Equate LLDPE EFDA-7047 is a linear low-density polyethylene resin produced from ethylene and butene-1 in a low-pressure gas-phase reactor. The grade is supplied as stabilised pellets for blown film extrusion. Its published melt flow rate is 1.0 g/10 min at 190 °C under 2.16 kg load according to ASTM D1238, equivalent to ISO 1133-1:2022 condition 190/2.16, and the base resin density is 0.918 g/cm³ according to ASTM D1505. The material is a butene-based LLDPE, not a metallocene ethylene-alpha-olefin copolymer. Its molecular weight distribution is broader than that of a typical solution-process metallocene grade, which contributes to bubble stability during blown film extrusion but limits ultimate puncture and tear resistance compared with hexene-based copolymers at equivalent density. The product is used in general-purpose film applications such as liners, carrier bags, overwrap film, lamination film, and agricultural film where melt strength, optical performance, and converter processability are balanced against ultimate toughness.

How Does Butene Comonomer Placement Modify Film Tear and Dart Drop in EFDA-7047?

The film property balance of EFDA-7047 is controlled by short-chain branch length and molecular weight distribution. Butene comonomer introduces ethyl branches into the polyethylene backbone. These branches are shorter than the butyl branches introduced by hexene; during blown film quenching, they are less effective at creating tie-chains between adjacent lamellae. Consequently, at identical density and melt flow rate, a butene-based LLDPE typically exhibits lower dart drop impact and lower Elmendorf tear than a hexene-based grade, although the difference narrows when the film is processed at higher blow-up ratios. The supplier-reported typical values for 40 µm blown film processed at a 2.5:1 blow-up ratio and 1.8 mm die gap are shown below. These values are not lot release limits; they reflect a specific film line configuration and will shift with film gauge, frost line height, and additive masterbatch addition.

The dart drop value is measured under ASTM D1709 Method A with a 38.1 mm diameter dart head and reports the F50 failure mass. Elmendorf tear is measured under ASTM D1922 using a pendulum tear tester. Machine-direction and transverse-direction tensile properties are measured under ASTM D882 using 25.4 mm wide film specimens and a 500 mm/min grip separation speed. Haze is measured under ASTM D1003 and gloss under ASTM D2457 at 45°. The table indicates that transverse-direction elongation is higher than machine-direction elongation, which is typical for blown film with cross-direction orientation developed at a 2.5:1 blow-up ratio. At blow-up ratios below 2.0:1, transverse-direction tear and dart drop values can decrease because the film develops less cross-directional orientation.

On single-layer blown film lines using grooved-feed single-screw extruders with screw diameters from 40 mm to 75 mm and length-to-diameter ratios from 25:1 to 30:1, EFDA-7047 is processed with barrel profiles from 170 °C to 220 °C. Die temperature is usually held between 190 °C and 210 °C. Typical die gaps are 1.5 mm to 2.5 mm, and blow-up ratios of 2.0:1 to 2.8:1 are common for general-purpose film. Because the melt flow rate is 1.0 g/10 min, screw speed may be pressure-limited before motor load limit is reached on small extruders. If die pressure exceeds the extruder safe operating limit, widening the die gap by 0.3 mm to 0.5 mm reduces head pressure more effectively than raising barrel temperature. Sustained melt temperature above 230 °C should be avoided; antioxidant consumption accelerates in the presence of oxygen, and oxidised gel particles can form at the die lip. Converter experience on 65 mm grooved-feed extruders indicates that bubble stability is usually acceptable when frost line height is held between 300 mm and 600 mm above the die. Published data for this specific configuration is limited, and line trials are required to set the exact operating window.

Pre-drying is not normally required when pellet storage relative humidity is below 60 %. If pellets are moved from cold storage to warm ambient air, surface condensation can produce splay and bubble defects. In such cases, a hopper dryer set at 60 °C to 70 °C for 0.5 h to 1 h is sufficient to remove surface moisture. EFDA-7047 is not hygroscopic; extended drying at high temperature is unnecessary and can oxidise the stabiliser package.

Masterbatch dispersion in EFDA-7047 is affected by the relatively low melt flow rate. On grooved-feed extruders with barrier screws and distributive mixing elements, let-down of a 40 wt% anti-block or slip masterbatch at 2 wt% to 5 wt% is typical. Screen packs of 80 mesh to 120 mesh are used to trap gels and agglomerates; back pressure rises as screens load. If masterbatch dispersion is poor, film defects appear as local haze bands or random dark specks. The correct screen area and back-pressure limit should be taken from the extruder manufacturer’s specification for the screw diameter and pressure class.

When EFDA-7047 Replaces High-Pressure LDPE in Single-Layer Blown Film

High-pressure LDPE grades at 0.918 g/cm³ to 0.925 g/cm³ density and 0.8 g/10 min to 2.0 g/10 min MFR contain long-chain branching. The long-chain branches provide high shear thinning and extensional strain hardening, which stabilise the blown film bubble and reduce draw resonance. When EFDA-7047 replaces such an LDPE in a single-layer line, the same screw speed normally produces higher die pressure because the linear polyethylene has a narrower shear-thinning response. The film typically shows higher tensile strength at break under ASTM D882 and higher dart drop impact under ASTM D1709 at equal gauge, but it also has a narrower bubble stability window and a greater tendency to bubble chatter at low frost line height. Haze measured under ASTM D1003 is usually lower in the LLDPE film than in a high-pressure LDPE film of the same gauge, and gloss measured under ASTM D2457 is higher. These optical differences allow down-gauging in clear overwrap and garment bag films, provided the winder and slitter controls are adequate for the lower stiffness of LLDPE.

Compared with a hexene-based LLDPE of the same 0.918 g/cm³ density and 1.0 g/10 min MFR, EFDA-7047 generally shows lower dart drop impact under ASTM D1709 and lower Elmendorf tear under ASTM D1922 because the ethyl branches from butene are less effective than the butyl branches from hexene in forming load-bearing tie-chains. The reduction is particularly visible in film gauges below 30 µm and at low blow-up ratios. Compared with a metallocene LLDPE film grade, EFDA-7047 has a broader molecular weight distribution; this improves bubble stability and may reduce melt pressure, but it lowers slow puncture resistance measured under ASTM D5748 and dart impact measured under ASTM D1709, and it raises haze measured under ASTM D1003. These film property differences are selection criteria, not inherent defects.

Fabricators often blend EFDA-7047 with high-pressure LDPE at 10 wt% to 30 wt% to improve bubble stability and reduce die pressure. The addition of LDPE reduces dart drop impact relative to 100 % EFDA-7047 because long-chain branching decreases tie-chain concentration and increases film stiffness. No single universal reduction factor applies; the actual property shift depends on the LDPE grade, blow-up ratio, and film gauge. A starting blend of 20 wt% LDPE is common on lines with die gaps below 1.5 mm, but the final blend ratio should be set by a film property design of experiments rather than by generic rule.

Because EFDA-7047 is a non-polar polyolefin, its oxygen and moisture barrier contribution in multilayer packaging is limited. Oxygen transmission rate measured under ASTM D3985 at 23 °C and 0 % relative humidity is orders of magnitude higher than that of EVOH barrier layers; water vapour transmission rate measured under ASTM F1249 is similarly high relative to PVdC or metallised films. Direct adhesion to EVOH or polyamide without tie resin will delaminate under load; maleic anhydride grafted polyethylene tie layers are required. The resin is not selected for chemical resistance to aromatic hydrocarbons, chlorinated solvents, or essential oils. Chemical exposure should be evaluated under ASTM D543 because swelling in toluene or limonene can reduce mechanical properties.

Compliance Boundaries and Film Wind-Up Limitations

Food-contact status is not automatically conferred by base resin selection. The as-supplied pellet may be used in food-contact articles when the finished film complies with FDA 21 CFR 177.1520 and EU Regulation 10/2011, including overall migration limits of 10 mg/dm² for aqueous, acidic, alcoholic, and fatty food simulants. The converter must assess migration of all additives, printing inks, and tie layers. REACH obligations for the final article depend on imported monomer and additive registration; the base polyolefin is exempt from registration as a polymer under REACH Article 2(9). The RoHS Directive 2011/65/EU applies to electrical and electronic equipment, not to food packaging; if EFDA-7047 is used as packaging for EEE, the converter must evaluate the packaged article under EN IEC 63000. The base polyolefin typically contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above 0.1 wt%, but additive masterbatches must be verified separately.

At wind-up, film without anti-block masterbatch may exhibit blocking depending on roll tension and winding temperature. The threshold roll tension varies with gauge, winding temperature, and surface treatment; published data for this specific configuration is limited. Converters should establish the safe winding tension by roll trials. Coefficient of friction under ASTM D1894 is influenced by slip additives, which migrate to the film surface over time; the measurement should be repeated at 24 h and 72 h after winding because erucamide migration is kinetic. Anti-block masterbatch addition at 2 wt% to 5 wt% is typically used to control roll separation in untreated film. Avoid storing pellets in direct sunlight or in unventilated silos at temperatures above 50 °C; extended UV exposure and heat-ageing deplete the antioxidant package and can increase gel count. Outdoor weathering applications require addition of hindered amine light stabilisers, and service lifetime must be validated under ISO 4892-2 or ASTM D2565 rather than estimated from base resin stability.