Novel method for 1 K waterborne polyurethane clearcoats
A new study presents a waterborne polyurethane clearcoat with excellent chemical and physical performance through an encapsulation system.
The encapsulation system in the study incorporated blocked polyisocyanate (b-PIC) as a crosslinker with an acrylic polyol to ensure homogeneous dispersion under water-based conditions. An acrylic polyol was designed to readily disperse into the water phase, fulfill the requirements of a clearcoat, and effectively encapsulate b-PIC. The structure of the core-shell encapsulation system enabled both homogeneous dispersion and close proximity between the acrylic polyol and b-PIC, resulting in a uniform crosslinking clearcoat.
Useful and inexpensive technology
Three different clearcoats were prepared: two water-based b-PIC systems with both polyisocyanate encapsulated dispersion (PED) and conventional b-PIC dispersion (CPD) without encapsulation, and a solvent-based (SB) b-PIC dispersion with ethyl cellosolve. Test results indicated that the PED clearcoat system could be utilised in waterborne coatings technology as a useful and inexpensive technology that addresses the need to reduce volatile organic compound (VOC) production for improved environmental protection.
The study has been published in Progress in Organic Coatings, Volume 177, April 2023.
Reading tip
The EC Tech Report provides you with all you need to know about the transition from solvent-based to water-borne coatings. Loaded with content from the European Coatings Journal, EC 360° as well as our most-read books.
