Henkel, 4Jet develop in-situ foaming technology for EV tires

Düsseldorf, Germany – Adhesives major Henkel and laser systems specialist 4Jet have developed a new process for the manufacture of 'silent' tires: streamlining the multi-step processes currently used by tire makers.

The German groups, on 5 Sept, unveiled the ‘Laser-Fit’ process, which involves the foaming of acoustic insulation inside the tire, rather than bonding in pre-foamed materials.

In the process, “a tailor-made acoustic foam is produced directly inside the tire from liquid starting materials, at the end of the tire line,” the partners explain in a press release.

According to the two partners, 'silent' tires lined with polyurethane foams are increasingly in demand to meet the need to reduce tire noise which is particularly noticeable within electric vehicles.

However, existing processes for producing the tires are complicated and costly, requiring an extra logistics line in tire factories to transport the foam for application at the end of the production line.

Furthermore, many additional manual or semi-automatic steps are required for logistics, cutting, applying adhesives and inserting the foam 'just-in-sequence' into the tire.

“As a result, the manufacturing costs of a tire increase by up to 25% and it is often impossible to integrate the technology into existing tire plants,” according to the companies' statement.

By directly producing the foam inside the tire, Henkel and 4Jet claim to have eliminated the complex logistics and processing steps currently used by tire manufacturers.

The technology, they add, also provides the tire manufacturer greater freedom in adapting the “foam’s geometry and volume” to the tire type, and thereby reducing waste generation.

According to the partners, the process involves a patented foam activation technology using laser after the foam has been applied.

Using Henkel’s Loctite adhesive brand, Laser-Fit produces “a large inner surface and a pore design specifically tailored for tire noise suppression,” said Dr Rainer Schoenfeld, global market strategy head in Henkel`s automotive component business unit.

According to Schoenfeld, 4Jet’s laser activation process precisely removes the foam skin, allowing the majority of sound waves to be absorbed by the foam surface rather than being reflected.