PP for Living Hinge Moulding: Best Specs and What to Avoid.
If you’re using Polypropylene (PP) for a living hinge, you could choose a homopolymer grade with a high melt flow index (MFI).
Best PP Type for Living Hinges:
✅ PP Homopolymer (HPPP)
- Higher strength and stiffness than copolymers
- Excellent fatigue resistance (essential for repeated bending)
- Good hinge memory (returns to original position after flexing)
✅ High Melt Flow Index (MFI: 10–30 g/10 min @ 230°C/2.16kg)
- Ensures good mould flow for thin hinge sections
Recommended Manufacturers:
- ExxonMobil
- Carmel Olefins
- Borealis
- Sabic
Avoid These PP Types:
❌ PP Copolymers – More impact-resistant but lower hinge durability
❌ Low MFI Grades (<10 MFI) – Harder to mold thin hinges
❌ Filled or Reinforced PP – Stiff but weak in fatigue resistance