Polypropylene (PP) comes in a wide range of grades, and two properties drive most of the decision: the melt flow index (MFI) and whether the resin is a homopolymer or a copolymer.
What MFI tells you
MFI measures how easily the molten resin flows. Low-MFI PP is more viscous and suits extrusion and raffia; high-MFI PP fills thin, complex injection moulds more easily. Picking the wrong MFI shows up as short shots, flashing or inconsistent output.
Homopolymer vs copolymer
- Homopolymer PP: higher stiffness and clarity - good for raffia, fibre, BOPP film and rigid mouldings.
- Random copolymer: better clarity and lower haze - used in clear packaging and housewares.
- Impact (block) copolymer: improved toughness, especially in cold conditions - used in crates, automotive and industrial parts.
Match the grade to the job
For woven sacks and raffia tape, a homopolymer with the right MFI keeps tape strength consistent. For a tough container, an impact copolymer resists cracking. For clear thin-wall packaging, a random copolymer gives the look you want.
Get a matched grade
Tell us your process and target MFI and we will source a matching producer grade with COA. Browse polypropylene grades or request a quote.