From rubber feet to shoes – Lenkki Oy makes shoe soles from used tires

The recycled raw material utilized by the Kankaanpää company, which specializes in shoe soles and parts, comes from Nokian Tyres' end-of-life tires.

Old tires are collected and processed into rubber powder by Suomen Rengaskierrätys Oy.

“We want to develop responsible production,” says Lenkki Oy’s CEO. Annamaija Mäkilouko.

Finnish Tyre Recycling and its research partner Apila Oy have succeeded in their development work. The material processed at the Loppe tyre recycling plant has been processed into a secondary raw material that is suitable for injection moulding and reduces the carbon footprint of production.

Lenkki uses an injection-molded compound, about one-third of which is tire powder. It replaces thermoplastic elastomer made from non-renewable petroleum-based raw materials.

In the initial phase, the company will utilize recycled raw materials in the soles of outdoor and walking shoes.

The tire makes the sole durable

Before introducing tire powder, Lenkki considered how the recycled raw material would fit into established production methods.

“However, Finnish Tyre Recycling and its research partner Apila Oy had done such good groundwork and tested its suitability for injection molding that it was easy to try it out,” Mäkilouko says.

Lenkki also tested the new raw material in a variety of ways in his laboratory and, among other things, carried out a two-stage occupational safety test by the Finnish Institute for Health and Welfare.

The recycled raw material proved to be safe and functional. The shoe sole's bending resistance and UV resistance were even improved.

Customers require recycled materials

Lenkki has previously utilized process waste from the textile and leather industries in its manufacturing. The percentage of recycled materials is stated in the product information.

“Our customers are increasingly asking about recycled materials and also requiring their use, and that's okay,” says Mäkilouko.

The CEO believes that the requirements of consumers as well as national and EU-level legislation regarding the raw materials used will only become stricter.

“Our goal is to grow with a circular economy concept and export-friendly products in Europe. As far as we know, others don’t utilize tires in the same way we do.”

Lenkki Oy's customers include domestic footwear manufacturers and the Finnish Defence Forces. Just under a third of production goes to international markets.

Added value to the Finnish circular economy

Finnish Tyre Recycling processes Nokian Tyres products and other used tyres at its recycling plant in Loppe.

The plant processes approximately 20 tons of tires annually into rubber powder and crumb for reuse in the plastics and rubber industry.

“Shoe soles are a good example of how brand new products can be made from old tires and create added value in the Finnish circular economy,” says the CEO of Finnish Tire Recycling. Risto Tuominen.

Text: Päivi Ikonen and Elina Saarinen, Uusiouutisetmagazine and Kemiamedia.fi

Photos: Lenkki Oy. Juha Alitalo, who is responsible for product development and design at Lenkki Oy, and CEO Annamaija Mäkilouko have decided to put the old tires underfoot.

Lenkki Oy CEO Annamaija Mäkilouko presents recycled raw material made from tires in Finland. “By using recycled raw material made in Finland, we can reduce emissions from both the production and transportation of the raw material,” says Mäkilouko.