Polymers used in novel ski binding technology

A revolutionary, all-plastic ski binding system has been developed that enables skiers to mount the binding to a cross-country ski without using fasteners. Dean Palmer reports

A novel, all-plastic ski binding system has been developed that allows skiers to mount the binding to a cross-country ski using a slide and 'click-on' concept, that enables easier and faster mounting. The 'Nordic Integrated System' (NIS), developed by ski manufacturers Madshus and Rossignol, with the help of ski-binding producer Rottefella, also allows the skier to adjust the binding, to complement his or her individual kick and technique, while offering improved stability and ski control. According to Robert Tomter, product development manager at Rottefella: "An important step in realising the NIS concept was identifying the right materials for its component parts. This was particularly true for the plate, which forms the critical connection between the ski and the binding. Distrupol was the first supplier to fully grasp the complex technical requirements of the project, given the combination of mechanical and chemical properties demanded. "With its materials know-how and technical support capabilities, Distrupol played a crucial role in supporting Rottefella in an extensive testing and evaluation programme. This ultimately resulted in an unconventional choice of material, but with the necessary properties at a competitive price," he continued. The NIS system comprises a plate, which is attached to the upper surface of the ski by producers Madshus and Rossignol in the final manufacturing step, making it an integral part of the ski. On top of this, Rottefella's new 'Nordic Norm' binding slides into place and locks easily in five different positions. "The real technical challenge was to match material to the NIS production and performance criteria," explained Jon Asle Sjoli, polymer engineer at Distrupol. "The plate material properties had to be close to those of the ski's top surface in order to maintain integrity and withstand the mechanical loads of skiing. It also had to resist low temperatures, snow, ice, water and exposure to UV radiation. "In addition to the physical and environmental stresses, the material of choice had to be resistant to chemicals such as wax removers, yet also be compatible with the adhesive bonding between plate and ski. This complex combination of demands led us to an extensive test programme involving a number of materials and, ultimately, we came to a non-traditional material choice for this type of application - LG Chem's ABS HI-100, which was able to satisfy all requirements," he pointed out. Delrin 127 POM from DuPont was selected for the ski bindings because of its high strength at low temperatures and its excellent 'snap-fit' properties, which enabled the innovative integration into the binding housing of the two locks that hold it in place on the ski. "The locks fit in corresponding recesses in the NIS plate and it is this system that makes it possible to re-position or completely remove the binding from the ski," explained Jon Asle.