Film Formation of 2K Waterborne Polyurethane Systems

By Philippe Olier, Imke Ludwig, Mathias Kind, Wilhelm Schabel, Joachim Krenn, Steve Meeker

Two-pack (2K) waterborne polyurethanes are increasingly used in coatings technologies. Examples of such coatings can be encountered in many different fields including metal coatings (for railway carriage, car refinish…), wood coatings (e.g., parquet flooring, furniture) or soft-feel coatings for plastic in the automotive industry. The benefits brought by waterborne technology can explain this growth. It is fully compliant with the new volatile organic compounds (VOC) regulations and contributes to better health and safety conditions for both workers and end users.

Of course, switching from solvent-based to waterborne technology implies technical challenges. Many improvements have been achieved during the past years to develop waterborne systems that can compete with solvent-based coatings. In the case of polyisocyanates, for instance, the ease of mixing in the formulation and the control of side reactions with water have been greatly improved by using hydrophilically modified polyisocyanates.