Hytrel® Ski Boot Collar

Ghost Rider Ski Boot from Salomon
Ghost Rider Ski Boot from Salomon

Renewably-Sourced DuPont™ Hytrel® in Ski-Boots From Salomon

One of the first applications of DuPont™ Hytrel® RS thermoplastic elastomer was launched in March 2009 in a sporting goods application when a product was launched by Salomon, a leading consumer supplier of sporting goods.  Hytrel® RS thermoplastic elastomer provides all the performance characteristics of traditional Hytrel® materials, while offering a more environmentally friendly solution than products that are entirely petroleum-based.  Hytrel® RS has been developed using a renewably sourced polyol derived from  non-food renewable sources.  It contains between 20 and 60 percent renewably sourced material.  The performance of Hytrel® RS products allows customers to reduce the use of petroleum-based materials in their products while continuing to meet the needs of the most demanding applications.

The collar of the Salomon ‘Ghost’ freerider alpine ski-boot constitutes one of the first commercial uses worldwide of DuPont™ Hytrel® RS (renewably-sourced) thermoplastic elastomer.  Providing all the traditional performance characteristics of Hytrel® for such a demanding winter sports application – including impact resistance and flexibility at low temperatures – the particular grade of Hytrel® RS used contains 27 wt% renewably sourced material. The Salomon “Ghost” ski-boot was available solely to Salomon-sponsored freeriders during the winter 2008/09 season, with its general release to the public in the winter of 2009/10.

“The portfolio of renewably sourced  polymers gives designers an alternative palette to work with,” said Marsha Craig, global  business director, renewably sourced materials -- DuPont Performance Polymers,  which offers a wide range of high-performance renewably sourced polymers to help industry  reduce dependence on depleteable petroleum-based products.

Ski-boot collars help provide a secure fit of the boot to the skier and protect the lower leg.  At the same time they need to be flexible enough to ensure a good and reliable transfer of movement from the leg to the ski.  Already familiar with the properties of the DuPont Hytrel® from its use for collars and soles of its Nordic ski shoes, the launch of renewably sourced grades of Hytrel® caught Salomon’s attention as it sought to decrease the use of petroleum-based products in its alpine ski-boots.  “We already knew Hytrel® could offer the required performance for the collar of our new ‘Ghost’ freerider boots as an alternative to polyurethane,” confirms Pascal Pallatin, alpine boot and advanced research project manager at Salomon (Annecy, France).  “The fact that we could now access a grade of the high-performance material with a significant renewable content is an additional selling point for our boots.”

Hytrel® RS thermoplastic elastomers provide all the performance characteristics of traditional Hytrel® materials, while offering a more environmentally friendly solution than products that are entirely petroleum-based.  Containing between 20 and 60 percent renewably sourced  material, Hytrel® RS thermoplastic elastomers are made using a renewably sourced  polyol derived from non-food renewable sources – and are, as molding for  Salomon confirmed, easily processed by conventional thermoplastic methods.  The properties of Hytrel® RS of particular relevance to this ski-boot collar application include excellent flex fatigue and flexibility at temperatures as low as -4°F /-20°C (versus polyurethane) and high impact resistance.  The collar is injection molded as a single piece and colored white using masterbatch.  The Salomon ‘Ghost’ motif is added to the collar using pad printing.

Comprehensive field testing by Salomon freeriders has demonstrated that Hytrel® RS best fulfills all requirements for the ski-boot collar in terms of elasticity, impact resistance, strength and stiffness.  “The freeriders returned with very positive comments on the boot’s behavior at low temperatures as well as its consistent behavior over a wide temperature range,” concludes Pallatin.

Salomon was born in 1947 in the heart of the French Alps and the birthplace of modern alpinism.  Driven by passion for skiing and design  innovation, Francois Salomon and his son, George, designed and perfected many of  the first modern ski bindings.  During the following 60 years, Salomon's commitment to innovative design and passion for mountain sports created a vast range of revolutionary new concepts in bindings, boots, skis and apparel for both alpine and nordic skiing and brought innovative solutions to footwear, apparel and equipment for snowboarding, adventure racing, mountaineering, and many other sports.  Today, Salomon products are sold in over 160 countries.