Material Guides · Aug 25, 2026
Three polyethylene families dominate flexible packaging, and buyers routinely face the same question: which one do I actually need? The answer is hidden in three numbers — density, melt flow index, and the comonomer story behind them.
This guide helps procurement teams read polyethylene data sheets like processors do, so you can specify the right film-grade resin — and avoid costly specification mistakes.
All polyethylene is built from the same monomer, but the arrangement of the polymer chains differs. Density is the single most important number on a PE data sheet because it tells you how crystalline the material is — and crystalline structure dictates stiffness, clarity, barrier and heat resistance.
MFI tells you how the melt flows under a fixed load. Lower MFI = higher molecular weight = stronger but harder to process. Higher MFI = easier processing but weaker film. Film grades typically sit at MFI 0.3–2.0; a grade like SABIC FJ00952 (MFI 0.05) is chosen exactly because its very high molecular weight delivers outstanding tear strength in thin shopping bags.
Most commercial film is not one resin — it is a blend. Processors combine HDPE and LLDPE to hit a stiffness-versus-toughness sweet spot, or add low-VA EVA (e.g. Hanwha Total 1310) to improve sealing and low-temperature performance. When you request a quote, share your target film properties rather than only a grade name — a good supplier will recommend the blend.
Send us your film requirements and our engineers will shortlist matching grades from stock.
Three polyethylene families dominate flexible packaging. Understand density, MFI and film performance to specify the right film-grade resin — and the right supplier.
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