BASF’s polyurethane chemistry gives runners and Adidas help with their ‘Boost’

How can polyurethane chemistry give runners the bounce they need to power through a 10k? BASF research scientist Dr. Frank Prissok has been developing the answer to that question. As a result, BASF’s new thermoplastic polyurethane, Infinergy^TM, has become an energy store for a runner or athlete, giving them a little extra spring in their step. Find out more about this incredible polyurethane science in our interview with Dr. Prissok below.

Q. What is Infinergy^TM and how did the idea for it happen?

A. Infinergy^TM is the first expanded thermoplastic polyurethane (E-TPU). It is a closed-cell elastic particle foam consisting of individual beads. The individual particles between five and ten millimeters in size are pressed and fused against one another in the manufacturing of parts. It is particularly lightweight (bulk density ~ 100g/l), very elastic, tensile and stretchy. The foam has high long-term durability and outstanding resilience – better than EVA (ethylene vinyl acetate), which has previously been used in the majority of sports shoe midsoles.
Infinergy can withstand temperatures of between -20 and +40 °C without any adverse effect and barely changes its functional properties.

Q. Did anything in particular inspire you?

A. I think the inspiration was a tennis ball. Light with high elasticity and rebound and a completely closed cell. But how to turn a tennis ball into a foam?
From my time in the BASF headquarter in Ludwigshafen I still had contacts to the polystyrene and polypropylen particle foam experts. We had to overcome several challenges but then succeeded in making a foaming test with a special grade of TPU and obtained the first particle foam. When we saw and felt this first sample we knew: This is something completely new.

Q. Your product will be used as a main sole-component of adidas’ new running shoe series “Boost.” What is the most exciting thing about innovating products like Infinergy^TM for the athletic and outdoor industries?

A. The strongest advantage for the runner is the temperature independent stiffness and the high energy return of Infinergy^TM.
The sealed air cells make the lightweight foam beads very elastic and provide the desired rebound effect. The very low glass transition temperature guarantees a broad temperature resistance.

Q. What was the biggest challenge you overcame?

A. After solving the chemistry challenges (recipe and process for blowing), finding an application and a customer was the important task. A big challenge was to build up a structure to combine BASF polyurethanes with BASF particle foam production and process.

Q. What is the next step after Infinergy^TM?

A. Never stop: We are looking for new recipes, production ways and applications for our Infinergy and for our Polyurethanes in general.

Watch BASF’s, Infinergy^TM, technology in action:

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