In a first for the footwear industry, Huntsman has developed a liquid thermoplastic polyurethane (LTPU) that enables the rapid manufacture of high-performing midsoles and is aligned with the circularity ambitions of brands manufacturing sports and athleisure footwear.
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 system is being officially unveiled today (19th September 2023) at SIMAC in Milan and at the FDRA’s Shoe Sustainability Summit in Portland, Oregon. To launch this unique, 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 per annum using the material.
Key benefits of SMARTLITE® O LTPU:
Easy to process:
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.
High performance:
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%.
Circular:
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.
Freedom of design:
For footwear designers, SMARTLITE® O LTPU system opens up new creative opportunities, 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 said: “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.”
Andreas Quade, Executive Board Director, Innovation & Technology at framas, said: “Huntsman’s SMARTLITE® O LTPU system is incredibly innovative. Helping to enable circular projects, it is a definitive step towards more environmentally friendly practices in the footwear industry. We’re excited by the interest the material has already generated and look forward to further discussions about the opportunities it presents.”
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