Proximity-driven high performance of a self-crosslinkable polymer for waterborne 1 K clearcoats

Abstract

Amid mounting concerns over volatile organic compounds emissions and environmental sustainability, clearcoat technology faces substantial challenges in the coatings industry. Waterborne (WB) coating systems, which use water as a carrier instead of organic solvents, offer promising solutions to these issues but encounter inherent dispersion problems, leading to poor final properties such as durability and optical gloss compared with those of their solventborne (SB) counterparts. Addressing this disparity underscores the critical need for ongoing research and innovation in coating technologies. To tackle these challenges, we developed a novel self-crosslinkable polymer for a WB 1 K clearcoat. This polymer integrates hydroxyl and blocked isocyanate groups within a single chain, aiming to enhance the appearance and mechanical properties of the resultant clearcoat. The designed system facilitates homogeneous dispersion and an appropriate proximity between functional groups to enable crosslinking in the water phase, resulting in advanced aesthetic and mechanical properties comparable to those of SB systems. Dynamic light scattering measurements confirmed the excellent dispersion stability, with an average particle size of ∼100 nm. Real-time crosslinking studies demonstrated similar final storage moduli and gloss levels between the WB and SB clearcoats. As a result of its self-crosslinking characteristics, the WB 1 K clearcoat exhibited superior mechanical properties, showcasing its potential for use as an environmentally friendly and sustainable coating. © 2025