Best Polymers for Living Hinges Explained.
A living hinge is a thin, flexible section of material (usually plastic) that connects two rigid parts, allowing them to bend repeatedly without breaking. To function well, the polymer used must be flexible, durable, and resistant to fatigue.
Best Polymers for Living Hinges:
- Polypropylene (PP) – Best Choice
- Excellent fatigue resistance
- High flexibility and toughness
- Cost-effective and widely available
- Used in bottle caps, flip-top lids, and containers
- Polyethylene (PE) – Good Option
- High-density polyethylene (HDPE) and low-density polyethylene (LDPE) both work
- LDPE is more flexible, HDPE is stronger
- Used in snap-on lids and simple hinge applications
- Polyoxymethylene (POM / Acetal)
- High mechanical strength and wear resistance
- Good for precision applications
- Less flexible than PP but still viable
- Nylon (PA)
- High strength and flexibility
- More resistant to wear but may absorb moisture over time
Polymers to Avoid:
- Polystyrene (PS) – Brittle, breaks easily
- Acrylonitrile Butadiene Styrene (ABS) – Too rigid, poor fatigue resistance
- Polycarbonate (PC) – Can crack under repeated flexing
For most applications, polypropylene (PP) is the best material due to its durability, flexibility, and cost-effectiveness. Are you designing a specific product that needs a living hinge?