Sometimes the simplest solution is the most powerful

How a reversible adhesive could make safety footwear easier to recycle

What if a safety shoe could be easily taken apart at the end of its life, allowing its individual materials to be reused? Over the next three years, EMMA will explore that possibility as part of the CircuTherm project, working alongside leading research institutes and industry partners to develop a so-called reversible adhesive.

“I was excited from the moment this idea was first presented to me," says Elroy Bongers, Head of Innovation and Sustainability at EMMA. "The idea is remarkably simple – and that's exactly what makes it so powerful.”

EMMA is one of the partners in the three-year CircuTherm project, which is developing a thermoplastic reversible adhesive. This innovative adhesive securely bonds shoe components during use, but can also be released again at the end of the product's life. Within the consortium, EMMA works alongside TNO, Eindhoven University of Technology, Maastricht University, Yparex B.V. and Hybrid Catalysis.

From permanent bonding to controlled separation

According to Elroy, reversibility is the key innovation. “A safety shoe is made from different materials that are firmly bonded together. That's essential for safety, comfort and durability during use. But at the end of the product's life, those strong connections become a challenge. High-quality recycling requires materials to be separated as cleanly as possible.”

Heating only where it's needed

One of the biggest advantages of the technology lies in the way the adhesive is heated.

“In conventional manufacturing, the entire shoe – both the sole and the upper – is heated in an industrial oven,” Elroy explains. “With this technology, only the nanoparticles inside the adhesive are heated. The heat is generated exactly where it's needed.” The result is a fast, fully electric and highly energy-efficient process. With an efficiency of up to 90%, less energy is wasted, CO₂ emissions are reduced and new circular manufacturing processes become possible.

"This is one of those rare opportunities where both sustainability and efficiency can improve at the same time.”

A rare win-win

For EMMA, the real value lies in combining sustainability with operational efficiency. “Many sustainability projects involve a trade-off between environmental impact and cost. This is one of those rare opportunities where both can improve at the same time. You can reduce energy consumption, speed up production and make products easier to recycle.”

What does this mean for the wearer?

“Ideally, nothing at all,” Elroy says. “Safety, comfort and quality will always come first. Our goal is for wearers to experience exactly the same performance, while we reduce the environmental impact behind the scenes. In the future, the technology may also create new opportunities for repair and lifetime extension.”

More than technology

While the technology shows great promise, Elroy stresses that it is only one part of the solution. As part of the CircuTherm consortium, EMMA contributes practical manufacturing expertise to ensure the technology can be applied in real production environments. “Researchers can develop brilliant ideas, but they also need to work on the factory floor and meet every performance requirement we set for safety footwear.”

Taking a shoe apart is only the first step. “You also need collection systems, partners that can process the recovered materials and ways to bring those materials back into new products.” According to Elroy, CircuTherm is therefore an important building block, but not the complete answer. “Creating a circular future requires collaboration across the entire value chain. That's why EMMA continues to invest in multiple initiatives that move us closer to truly circular safety footwear.”
 

“Circularity requires collaboration across the entire value chain.”

Looking ahead

For EMMA, CircuTherm fits into a much broader ambition. “Our dream is for EMMA to become the circular hub for safety footwear in Western Europe. Not only by manufacturing safety shoes, but also by bringing materials back, recovering their value and giving them a second life. Projects like CircuTherm help us move one step closer to making that vision a reality.”