BASF develops PU foam with renewable polyol for sports helmet

DENVER (ICIS)–BASF has developed a polyurethane (PU) foam for a sports helmet that relies on a renewable polyol, a mixture of open and closed cells and a density gradient to protect players from high-speed collisions.

The foam, Elastopan 42320, is a finalist for the Polyurethane Innovation Award, given by the Center for the Polyurethanes Industry (CPI) during the Polyurethanes Technical Conference.

The sport-equipment company Xenith is using the foam in its LOOP helmet for nontackle US-style football.

The foam stands out because a renewable plant-based polyol makes up more than 80% of the polyols in the PU, said Mohamed Bouguettaya, BASF strategic marketing manager. He was also the project manager for Elastopan 42320. He made his comments in an interview with ICIS.

The feedstock for the polyol is not from the food chain, so it avoids the issues that arise from renewable chemicals that are made from food-based sugars or edible oils.

The polyol does not just boost the sustainability profile of the PU foam. The Elastopan impact-foam absorbs the least amount of moisture when compared with the benchmark foams used in the helmets, Bouguettaya said.

The foam needed to have low water absorption because Xenith was using it in a sports helmet. The people wearing the helmets will sweat a lot, so a foam that absorbs less moisture will produce less odour, harbour fewer germs and feel more comfortable.

At the same time, BASF’s foam could still absorb enough energy to protect players in the case of falls and collisions.

Elastopan 42320 has a mixture of open and closed cells, unlike typical visco-elastic foams, Bouguettaya said. The ratio of open to closed cells is one of the key characteristics that improves how well Elastopan 42320 dissipates energy and recovers its shape after collisions.

Elastopan 42320 also has a density gradient, with the outside being denser than the inside, Bouguettaya said. That density gradient protects players from a wide range of collision intensity.

In particular, the density gradient improves how well the foam performs during high-speed collisions, Bouguettaya said. “This was one of the unique properties of our foam.”

Other features of Elastopan 42320 allow it to maintain its absorption qualities at lower temperatures. Other foams begin to stiffen and lose their absorption properties when the temperature falls.

BASF worked closely with Xenith to develop a foam that had the right characteristics for the helmet, he said. This collaboration was critical because it allowed BASF and Xenith to test the prototypes regularly and use analytical tools in the sports industry to develop a foam.

Because of its versatility, the foam can be used in other sports that require protection from collisions, Bouguettaya said. The density and hardness of the foam can be altered and it can be formed into different shapes.

Outside of sports, Elastopan 42320 could be used to protect first responders or military personnel. Floor mats and shoe soles are other potential uses, Bouguettaya said. “Where energy absorption is needed, we feel that it’s going to be a good fit.”

The Polyurethanes Technical Conference runs through Thursday.

Interview article by Al Greenwood