Biobased Thermoplastic Copolyester

A biobased thermoplastic copolyester specifically designed for foamed athletic footwear has been launched by Celanese Corp. The new Hytrel TPC RS40F2 is the latest addition to the company’s Hytrel TPC Eco-B portfolio. Incorporating a minimum of 20% segregated biocontent, Hytrel TPC RS40F2 foamed using a physical supercritical fluid (SCF) foaming process helps support the sustainable development objectives of athletic footwear brand owners and manufacturers. The biocontent is verifiable via the C14 method.

Pristine white foamed biobased Hytrel TPC RS40F2 is well suited to the midsole components of athletic footwear as it is said to deliver lightweighting opportunities while elevating energy return performance with excellent rebound and resilience associated with other Hytrel TPC grades. Hytrel TPC (originally developed by DuPont) is widely used in different industries due to its advantages in lightweighting, heat insulation, sound absorption, shock resistance, moisture resistance and corrosion resistance.

Physical SCF foaming, which is leading a process technology transformation, has been show to result in a unique cell structure with elevated properties and good skin compatibility. The process itself offers environmental benefits as there are no corrosive foaming agent residues to impair mechanical properties.

Additionally, it generates low odor/emissions and exhibits no toxicity. The traditional use of materials for insoles and midsoles has typically relied on chemical foaming agents that can generate volatile organic compounds (VOCs), which react with sunlight to form ground-level smog, an environmental concern. Celanese is collaborating with Xingxun Enterprise, an innovative processor, to produce world-class foamed polymer applications. Experts from both companies have worked together to successfully develop the processing of Hytrel TPC RS40F2 shoe soles using physical SCF foaming technology.