LyondellBasell HDPE F-FA70000 is a high-density polyethylene resin supplied as stabilised translucent pellets and intended for blown film extrusion. The grade is defined by two manufacturer-published nominal values: density 0.956 g/cm³ determined under ASTM D1505, and melt flow rate 0.70 g/10 min at 190°C/2.16 kg under ASTM D1238. The density positions the product in the high-stiffness portion of the HDPE film segment; the melt flow rate places it in the medium-molecular-weight processing class, below injection moulding grades but above high-molecular-weight film grades with MFR under 0.10 g/10 min. The additive system includes thermal stabilisation for extrusion; the resin is not a clarity-enhanced grade and should not be specified where contact transparency or haze below 10% on 50 μm film is mandatory.

Applications reported for this product include T-shirt grocery sacks, side-welded bags, bin liners, industrial liners, and high-stiffness packaging film where moisture vapour barrier contributes to shelf life. Its differentiation from other products arises from the combination of density and molecular weight: compared with a typical 0.949 g/cm³ HDPE film resin, flexural modulus is higher, but tear and dart impact are lower; compared with butene-LLDPE, it offers lower moisture vapour transmission and higher tensile yield stress at similar gauge, but lower puncture resistance. These trade-offs are quantified in the sections that follow via standard test methods.

Which Processing Conditions Govern Bubble Stability and Output in F-FA70000 Blown Film Lines?

For this density and melt flow class on conventional monolayer blown film lines, the recommended melt temperature window is 193°C–232°C. Extruders with 24:1 to 30:1 L/D and grooved feed sections are suitable; spiral mandrel die gap should be held between 1.0 mm and 1.6 mm. Blow-up ratio is commonly 2.0:1 to 4.0:1. Operating below 190°C elevates melt viscosity, increases backpressure, and can initiate chevron-type melt fracture when the die gap is below 0.8 mm. Operating above 232°C shortens stabiliser protection; oxidative gel particles appear as fisheyes in film at thicknesses below 25 μm. Internal bubble cooling with air at 10°C–15°C is used to stabilise the frost line and raise output without cooling the die lips.

Frost line height influences the balance of machine-direction and transverse-direction orientation. A frost line of 6–10 die diameters is typical. If the frost line is held below 6 die diameters, transverse direction strain hardening decreases and gauge bands may develop at tolerances worse than ±8%. If the frost line exceeds 12 die diameters, bubble wandering increases and production-speed variations create film roll camber. These constraints are more pronounced for F-FA70000 than for a high-molecular-weight HDPE with MFR below 0.10 g/10 min, which has higher melt strength but requires wider die gaps and higher extruder torque.

Regrind addition up to 20 wt% is common for this product in non-food-contact sacks; for direct food contact, the processor must validate that regrind source and level comply with the applicable food-contact regulation. Pellets should be kept dry: although HDPE is not hygroscopic to the extent of condensation polyesters, surface moisture from outdoor storage above 60% RH can create melt stream voids and odour in thin film. A hopper dryer at 60°C–70°C for 2 h is sufficient when surface condensation is present. Production-scale data for this exact grade is limited; these drying values are derived from standard HDPE film handling practice rather than a grade-specific supplier drying specification.

Comparative HDPE Film Portfolio Positioning

Within the supplier’s HDPE film range, F-FA70000 occupies the high-density, medium-molecular-weight position. Increasing density from 0.949 g/cm³ to 0.956 g/cm³ raises the 1% secant modulus from roughly 900 MPa to 1,150 MPa in machine direction film, depending on processing. Dart drop impact under ASTM D1709 Method A typically declines by 15–25% for the same thickness. Compared with high-molecular-weight film HDPE, the lower melt viscosity of F-FA70000 reduces motor load at equivalent screw speed but also reduces bubble stability at extreme blow-up ratios above 5:1. Compared with LLDPE, the HDPE grade has a moisture vapour transmission rate that is approximately 50% lower at 25 μm, but dart impact and tear resistance are lower. These differences define the application window: F-FA70000 is selected when stiffness and moisture barrier control performance, and is not selected when repeated puncture or high-speed dart impact dominates.

Rheological characterisation by capillary rheometry at 190°C indicates a shear-thinning viscosity profile typical of HDPE with an MFR of 0.70 g/10 min. At an apparent shear rate of 100 s⁻¹, the apparent melt viscosity is approximately 1,200 Pa·s; at 1,000 s⁻¹, it falls to approximately 350 Pa·s. These values are derived from generic viscosity curves for HDPE film resins at equivalent density and melt flow, not from a supplier-published capillary rheometry data set for F-FA70000. The high shear sensitivity should be considered in die design; the spiral mandrel clearance should be kept above 0.8 mm to avoid excessive shear heating.

When F-FA70000 Replaces a 0.949 g/cm³ HDPE in Grocery Sack Applications

The density increase to 0.956 g/cm³ changes conversion behaviour. On side-welded grocery sack lines running at 120 cycles/min, the higher secant modulus improves top-opening strength and reduces sag under load, but the lower transverse-direction Elmendorf tear requires validation on the specific bag geometry. Heat sealing is typically performed at jaw temperatures of 135°C–160°C with dwell times of 0.3–0.5 s and seal pressure of 0.4 MPa. Above 165°C, thin sections may show draw-down thinning at the seal interface, and seal strength variability increases under ASTM F88 testing. Because stiffness rises, converters may downgauge by 5–10% when replacing a 0.949 g/cm³ HDPE film, provided dart impact and tear requirements remain within specification. The moisture barrier improvement also supports dry product protection.

In print and bag-converting, the nonpolar surface of F-FA70000 requires corona treatment. Surface tension should be raised to above 38 mN/m before flexographic ink adhesion testing under ASTM F2252 or tape-adhesion methods. Without treatment, ink adhesion is poor. Corona discharge power is typically increased by 10–15% compared with treated LDPE film of equivalent thickness because of the higher density and lower surface-energy recovery rate. Post-treatment decay is slower for HDPE than for LDPE, but re-treatment may be required if film is stored longer than 48 h in humid conditions.

Masterbatches and processing aids must be selected for HDPE viscosity. Films using 4 wt% colour masterbatch can shift melt viscosity; if a low-molecular-weight carrier is used, output may increase but dart impact decreases. Incompatible additives, particularly certain amine-based lubricants or hygroscopic fillers, can plate out on the die lip and create melt fracture. The supplier should be consulted before combining F-FA70000 with fluoropolymer processing aids at levels above 800 ppm, because excessive processing aid can cause bubble instability and print adhesion loss.

Compared with a high-molecular-weight HDPE film resin with MFR 0.08 g/10 min, F-FA70000 has lower zero-shear viscosity and lower melt strength. In blown film, this translates to a maximum blow-up ratio typically below 5:1 for F-FA70000, whereas HMW-HDPE can process at 6:1–8:1. The lower viscosity also reduces energy consumption; specific energy input on a 75 mm extruder is typically 0.28–0.32 kWh/kg for this product class, compared with 0.34–0.38 kWh/kg for HMW-HDPE at equivalent output. Compared with an injection moulding HDPE with MFR 20 g/10 min, F-FA70000 cannot fill thin-wall sections with flow length-to-thickness ratios above 200:1 and is not suitable for injection moulding; the product is designed for film extrusion.

Food-Contact Compliance, ESCR, and Organoleptic Limitations

Environmental stress crack resistance for this density class under ASTM D1693 Condition B, 100% Igepal, generally ranges from 50 h to 200 h F50. The grade-specific F50 value should be obtained from the current supplier datasheet because comonomer type, molecular weight distribution, and stabiliser package alter ESCR at fixed density. The resin is represented by the supplier as complying with FDA 21 CFR 177.1520(c) 3.1a/3.2a and EU Regulation No 10/2011 for plastic materials intended for food contact. These declarations apply to the base resin; the finished article must be tested for overall migration and specific migration under the intended food simulants.

Organoleptic transfer from the natural grade is low, but the addition of colour masterbatch or post-consumer recycled material can introduce taint and odour. Dry bakery products packaged at temperatures above 40°C in high-colour-load films have shown sensory transfer when low-molecular-weight organic pigments are used. For fatty foods, migration testing should be conducted at the intended temperature and time. The resin should not be combined with amine-based long-term heat stabilisers without supplier approval; such combinations may generate interfacial plate-out on the die and reduce film clarity.

Storage life in unopened bags under 25°C and <50% RH is typically 24 months from the manufacturing date, based on standard polyolefin stabiliser behaviour. If the material is stored in direct sunlight or at ambient temperatures exceeding 40°C, yellowing and melt flow drift can occur. Inventory should be used on a first-in-first-out basis. The product is not recommended for medical implant, pharmaceutical primary packaging, or applications requiring long-term outdoor UV resistance without carbon black or UV stabiliser addition. Published data for long-term weathering of this specific formulation is limited; outdoor service requires a separately stabilised compound.