Fraunhofer scientists develop safer method to produce polyurethane without toxic isocyanates

Potsdam, Germany – Researchers at the Fraunhofer Institute for Applied Polymer Research (IAP) have developed a new method for producing polyurethane without the use of toxic isocyanates, a key ingredient traditionally required in the manufacture of the widely used polymer.

Polyurethane is found in a broad range of products, including furniture foam, insulation materials, coatings, adhesives, and medical devices. While finished polyurethane products are generally safe, the production process relies on isocyanates, which are known to pose serious health risks such as respiratory irritation, asthma, and allergic reactions. Manufacturing facilities must therefore operate under strict safety regulations to protect workers.

The new approach, developed as part of the CO₂NIPU research project, replaces isocyanates with harmless dicarbamate compounds. These compounds are synthesized using carbon dioxide, offering an additional environmental benefit by incorporating CO₂ into the production process. By eliminating toxic substances from manufacturing, the method significantly improves workplace safety and simplifies handling requirements.

The process involves combining dicarbamate with polymer diols and chain extenders and heating the mixture to approximately 180 to 190 degrees Celsius. The resulting polyurethane has the same molecular structure and material properties as conventionally produced polyurethane. Although the reaction takes longer—several hours instead of minutes—the slower process allows for greater control and improved material consistency.

The project is being carried out by a consortium of Fraunhofer institutes, including IAP, the Fraunhofer Institute for Chemical Technologies, the Fraunhofer Institute for Manufacturing Technology and Advanced Materials, and the Fraunhofer Institute for Environmental, Safety and Energy Technology.

In addition to developing the production process, researchers are working on recycling methods that would allow polyurethane products to be broken down and reused, supporting a more circular plastics economy. The technology has already progressed beyond laboratory scale, with a pilot plant capable of producing several kilograms of the isocyanate-free polyurethane. Plans are underway to scale production to hundreds of kilograms.

Initial applications are expected in the medical field, where the material is being tested for use in catheter tubing and specialized adhesives. Researchers say the innovation could pave the way for safer, more sustainable polyurethane production across multiple industries.