According to Bayer MaterialScience, transparent grades of Desmopan thermoplastic polyurethane (TPU) have set new trends and are being used by more and more manufacturers. In response to this, the company has introduced Desmopan DP 9650DU, DP 9659DU, DP 9662DU and DP 9665DU, which are said to represent a new generation of aromatic ether TPUs that offers even better performance.

“The strength of the new grades lies in the significantly improved low-temperature flexibility and low-temperature impact strength. These features mean that ski boots can be made stronger and manufactured in thinner wall thicknesses, thus allowing greater design freedom. This is especially true for areas where two different TPU materials overlap,” said Luigi Cermesoni, head of the company's Sports & Leisure TPU segment.

Compared with the first generation materials, the new products are said to have improved free-flowing properties. This makes more complex parts geometry easier to produce and allows gentler processing at lower injection pressures. Crystallisation has also been optimised and the melt solidifies even faster, which reduces cooling and cycle time, thus increasing productivity.

The new plasticiser-free and UV-stabilised TPU grades are available in hardnesses of 50 to 65 Shore D, enabling their use for both hard structural parts and, for example, soft shells and shafts. Desmopan 9650DU and Desmopan 9659DU are particularly suited to the trend for softer ski boots.

The new materials are already being used by manufacturers such as Tecnica (in its Diablo model) and Nordica (in its Speedmachine model).