Huntsman has developed a liquid thermoplastic polyurethane (LTPU) that enables the rapid manufacture of high-performing midsoles, and this innovation is in line with the circularity ambitions of brands manufacturing sports and athleisure footwear.
To launch this excellent, lightweight product, Huntsman has joined forces with the framas Group. Ready to partner with brands on sampling and the fulfilment of orders, framas has capacity to produce up to two million soling constructions annually using the material.
Easier to use than expanded forms of
TPU, which require complex procedures such as supercritical foaming and steam chest molding, SMARTLITE® O LTPU system can be processed in a single step that uses significantly less water and energy and generates less waste and carbon emissions. Crucially, Huntsman’s SMARTLITE® O LTPU system can also be converted and repurposed into new materials either in its post-industrial or post-consumer form.
Huntsman's SMARTLITE® O LTPU offers several key advantages: Processed on low pressure casting machines, SMARTLITE® O LTPU system is simple to use, scalable and can help streamline shoe manufacturing.
With in-situ polymerization, adhesive-free bonding of midsoles to TPU outsoles, and fast demold rates, cycle times for the SMARTLITE® O LTPU system are short. Besides, with a density of 250 kg/m3, Huntsman’s SMARTLITE® O LTPU system produces superior, hydrolysis resistant midsoles that offer long-lasting, step-in cushioning comfort with a rebound of more than 50%.
SMARTLITE® O LTPU system is the ideal solution for brands looking to use circular midsole materials and lower the carbon footprint of their manufacturing processes – without compromising performance or quality.
Supporting circular economy initiatives, soling units featuring a SMARTLITE® O LTPU midsole and a TPU outsole can be mechanically repurposed – if the correct reprocessing infrastructure is available. For example, manufacturers can mix post-industrial recycled SMARTLITE® O LTPU content with virgin TPU to create new outsoles and cupsoles. Huntsman can also make bio-based versions of the material.
SMARTLITE® O LTPU system also opens up new creative opportunities for footwear designers, delivering enhanced surface definition without silver lines or the popcorn effect. It is also easy to color and create striking fade effects.
Alexis Bortoluzzi, Senior Director Global Elastomers at Huntsman, commented: “For footwear brands pursuing circularity and looking to lower their carbon footprint, SMARTLITE® O LTPU system provides a very clear pathway.
The material stands out from the competition, offering multiple advantages over and above PU, ETPU and EVA. A number of big brands have already expressed considerable interest in the technology, and we look forward to working with framas to bring the material and all its benefits to market.”
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