Expanded TPU right for running shoes, BASF says
02/07/2013
On bringing the new closed-cell particle foam to market, it highlighted that sports brand adidas had been involved in an early joint-project, developing a new running shoe called Energy Boost “in close partnership” with BASF.
“When you talk to runners,” the chemical company said at the time of the formal launch of Infinergy, “they always express a need for good cushioning. In running shoes, this is the function of the midsole: in just a few milliseconds, it absorbs the kinetic energy generated by the runner as the foot lands and returns some of it to the runner while the foot is pressed down. High elasticity and deformability in the material that is used will increase the efficiency with which this happens.”
Runners used to have to choose between hard, elastic competition shoes or very soft training shoes offering a lot of cushioning, it continued, but insisted that adidas and BASF have resolved the dilemma by working together on it for almost three years. They have now confirmed adidas Boost technology as the world’s first application of the Infinergy material.
Energy Boost, the first running shoes that adidas has produced using the technology, combine softness and high elasticity in the midsole. During materials testing, adidas simulated on test machines the forces and deformation that occur during running, confident that this would allow it to calculate wear and energy return. To guarantee maximum performance in all seasons and all climate zones, the shoes were tested across a temperature range from -20 to +40 degrees Celsius.
In tests in a biomechanics laboratory, adidas product developers tested the stability of the running shoes and the effect of the products on the performance of athletes, using the VO2max test, which measures athletes’ oxygen uptake, and a range of elite athletes, including marathon world record-holder Patrick Makau, took part in trials to test the comfort and durability of the new shoes.
Boost technology compared favourably against cushioning systems based on ethylene-vinyl acetate (EVA), BASF said later. “No other midsole on the market generates more energy return,” it continued. “Compared to EVA, Boost shows three times better temperature resistance in its deformation behaviour with less hardening in the cold and less softening at high temperatures. Its durability under cyclical dynamic loading is also significantly better than with EVA cushioning systems.”
Nearly all the runners who tested the Energy Boost shoes highlighted what BASF has called “a special feeling” produced by the shoe when they were running.
Adidas launched the Energy Boost shoes in February and by July had sold around 250,000 pairs worldwide.
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