Gecko-inspired TPUs add grip to ‘circular’ footwear

The Woodlands, Texas - Huntsman has developed a range of thermoplastic polyurethane (TPU) materials for the production of footwear with enhanced grip, durability and ‘circularity’.

Tailored for use in soling applications, the new Avalon Gecko TPU series includes an extrudable grade for creating "super thin" outsoles and a product that can be foamed to produce a very low density material with a unique touch and feel.

Huntsman said it was inspired the extraordinary grip of geckos in developing the TPUs, which are said to offer comparable slip performance to rubber in both wet and dry conditions.

Target applications include outsoles for running, hiking and safety shoes, Huntsman noting that its Gecko range encompasses products that are “soft (shore 60-65A) yet highly durable with excellent abrasion resistance.”

These include: an opaque, injectable grade that is ideal for safety shoes; a transparent, extrusion grade optimised for running applications; a transparent, injectable grade for exceptional wet slip performance.

The extrudable version is said to enabling the creation of outsoles that are up to 50% thinner and lighter than conventional outsoles, without compromising quality, performance or durability.

All TPU grades offer adhesive-free bonding when paired with other TPU midsole materials and, thanks to their compatibility, can be mechanically recycled with minimal impact on material performance.

In-house testing of the regranulated TPU showed no signs of degradation in performance, said Huntsman, while noting that” the ability to perform mechanical recycling is dependent on end of life take-back programs and a recycling ecosystem being in place.”

The development of the new TPUs “represents a significant advancement towards achieving circular footwear,” claims Matthew Canoy, global marketing director PU Elastomers at Huntsman.

"Developed to be dependable, durable, and with circularity in mind, the TPU materials ensure that sustainability and high performance are in lock step with one another, with no compromises,” said Canoy.