ETPU, short for Expanded Thermoplastic Polyurethane, has transformed the world of performance footwear. Known for its springy feel and extreme durability, it’s the go-to midsole material for brands seeking energy return, resilience, and comfort without compromise.
Originally brought into the spotlight by Adidas Boost, ETPU is now used across performance running, lifestyle, and increasingly — in safety and workwear applications. At Alcmy, we use ETPU in several of our top-performing outsoles, including Trampoline 2, Ultra, and Firebird.
Why Use ETPU?
ETPU midsoles are created by expanding TPU beads into a microcellular foam. The result? A material that’s light, resilient, and incredibly responsive — ideal for industries that demand cushioning and durability over time.
Compared to traditional EVA or TPU, ETPU excels in areas like:
- Energy Return
- Fatigue Resistance
- Temperature Stability
- Longevity
Key Material Properties of ETPU
Here are some typical performance benchmarks for ETPU foam:
- Energy Return: 70–75%
- Density: 0.15–0.25 g/cm³
- Tensile Strength: ~12–15 MPa
- Elongation at Break: 400–500%
- Compression Set (24h @ 50% strain): <10%
- Operational Temperature Range: −20°C to +40°C
These properties make ETPU ideal for long-wearing footwear that demands high rebound and stability, even in harsh conditions.
ETPU in Alcmy Products
At Alcmy, we believe in leveraging the best materials in the most functional way possible. ETPU features prominently in several of our products:
- Trampoline 2
Combines dual-layer ETPU foam with a central TPU shank in a patented construction. Designed for safety boots requiring exceptional comfort and energy return. - Ultra
A sleek safety outsole with an ETPU midsole and a trail-inspired rubber outsole. Perfect for brands seeking athletic styling without compromising durability. - Firebird
Uses an internal ETPU foam caged in a transparent TPU shell. This layered design offers premium rebound and visual differentiation — ideal for advanced safety footwear. - Q-Blue
A versatile and color-blockable safety sole that balances comfort and modern design — thanks to its ETPU midsole foundation.
Final Thoughts
ETPU represents the next generation of midsole innovation — a perfect balance between cushioning, rebound, and long-term performance. Whether you're designing for safety, sport, or style, this material offers the flexibility and technical edge needed to elevate your footwear products.
Want to explore how ETPU can be integrated into your next project? Get in touch with our team and discover the difference premium midsole engineering makes.
