The Woodlands, Texas – A new liquid TPU system has been launched by Huntsman, in conjunction with shoe component manufacturer Framas. The Smartlite O LTPU system was designed for the rapid manufacture of high-performing midsoles.
Huntsman said that the system is easier to use than expanded forms of TPU, as these require complex procedures such as supercritical foaming and steam chest moulding. The new system, it said, can be processed in a single step, and uses less water and energy while creating less waste and reduced carbon emissions. Both industrial scrap and end-of-life post-consumer foam can be converted and repurposed into new materials.
The system is processed on low-pressure casting machines. Huntsman said it is simple to use, scalable, and can help streamline shoe manufacture. Cycle times are short, thanks to in situ polymerisation, adhesive-free bonding of midsoles to TPU outsoles, and fast demould rates.
Huntsman said the material has a density of 250kg/m3. Midsoles made using it are claimed to be long lasting, with a rebound of more than 50%. Biobased versions are also available.
Framas is using the material in conjunction with a 12-station machine from Gusbi at its headquarters in Pirmasens, Germany. It also has two 80-station Gusbi machines in place in Vietnam for production ramp-up when required. It has the capacity to produce up to two million soling constructions a year using the material.
The new system was unveiled at the Simac show in Milan and also the FDRA’s shoe sustainability summit in Portland, Oregon.