Isocyanate-free 2K DTM coating targets gloss and corrosion

Driven by the demand for more sustainable and health-conscious coating technologies, this thesis explores the development of a water-borne, isocyanate-free two-component (2K) direct-to-metal (DTM) coating. The work investigates the potential of such a system as an alternative to conventional 2K polyurethane coatings, which typically rely on isocyanate-based hardeners associated with handling and toxicity concerns. A particular focus is placed on achieving high gloss and reliable corrosion protection.

The formulation strategy follows a modular approach, designed to enhance economic efficiency while allowing flexible adaptation to different application requirements. By combining a carboxy-functional acrylic dispersion with epoxy-functional trialkoxysilanes, the developed system leverages complementary crosslinking chemistries to achieve the desired performance profile.

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Mechanical performance, light fastness and gloss largely achieved

The experimental results indicate that the newly developed coating can be regarded as a viable alternative to established 2K polyurethane systems. The innovative combination of acrylic dispersion and silane chemistry meets the requirements of a broad performance profile, with mechanical properties, light fastness and gloss largely reaching the targeted levels.

Outlook on long-term corrosion behaviour

While the initial performance assessment is promising, the author notes that further investigations are necessary to fully characterise the long-term corrosion protection provided by the system. Future research should therefore focus on extended durability testing to validate the system’s suitability for demanding industrial DTM applications.

Source: Bauknecht, K., Entwicklung einer wässrigen isocyanatfreien 2K-DTM-Beschichtung mit Fokus auf Glanz und Korrosionsschutz. Supervisor: Prof. Dr. Markus Schackmann (2025).

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