Green Breakthrough in Polyurethane Production Without Toxic Isocyanates

Researchers at the Fraunhofer-Gesellschaft have developed a novel, more sustainable method to produce polyurethanes (PUR) — versatile plastics used in products from furniture and insulation to medical tubing — without employing toxic isocyanates, which are traditionally indispensable but hazardous and linked to respiratory issues and strict safety controls during manufacture.  

In the CO2NIPU (non-isocyanate polyurethane) project led by the Fraunhofer Institute for Applied Polymer Research, scientists replaced isocyanates with benign dicarbamates, synthesised by reacting carbon dioxide and methanol with diamines under pressure, significantly reducing workplace health risks and lowering greenhouse gas emissions in production. The resulting polyurethanes have identical molecular structures to conventional materials, meaning existing expertise and applications can be directly adapted, while the modular system of reactants allows tuning of properties such as elasticity and adhesion.  Although reactions with dicarbamates proceed more slowly — taking six to eight hours compared with minutes for isocyanates — this enhances process control and cuts waste and quality variation.  

The project also incorporates recycling strategies for used PUR materials, contributing to a more circular plastics economy.  Initial commercial-scale steps include pilot production of non-isocyanate polyurethane and explorations into medical applications such as biocompatible catheter tubes, as well as adhesives to bond components, signalling a practical advance towards safer, greener industrial polyurethane production.

Source: Fraunhofer