The melt flow index, or MFI, also called melt flow rate (MFR), measures how easily a molten plastic flows. It is the weight of polymer, in grams, that flows through a standard die in ten minutes under a set temperature and load, tested to ISO 1133 or ASTM D1238.
A low MFI means a thick, viscous melt with high melt strength, suited to blow moulding, pipe and blown film. A high MFI means an easy-flowing melt suited to injection moulding. Polyethylene is normally tested at 190 degrees Celsius and polypropylene at 230 degrees Celsius, with a 2.16 kg load. For recycled granules, a stable MFI from batch to batch is as important as the value itself. It is the first figure converters look for on a technical data sheet.
CII Sustainable Plastic Packaging Awards 2026
Lucro took home the Excellence award for Incorporation of Recycled Content in both rigid and flexible packaging at the Confederation of Indian Industry’s Sustainable Plastic Packaging Awards 2026:
Post-consumer plastic, back on the shelf as bottles and pouches. The jury noticed.
