New Low-Viscosity Acrylic-Urethane Prepolymers and Their Acrylated Oligomers for Moisture and UV-curable Coatings

摘要

This paper describes a new class of urethane acrylate oligomers for weatherable UV-curable systems. Unlike commercial urethane acrylates that are based on polyether or polyester polyols, this new class of urethane oligomers is based on acrylic polyols. These new acrylic polyols are unique in that they produce low-viscosity, non-gelling urethane prepolymers with isophorone diisocyanate. These prepolymers can be further treated with hydroxy-functional acrylates such as hydroxyethylacrylate (HEA) or caprolactone acrylate (CA) to yield low-viscosity acrylated urethane acrylic oligomers. By replacing the polyester and polyether backbone in urethane acrylates with an acrylic backbone, this chemistry opens the door to more weatherable UV-curable coatings, with properties that approach twocomponent urethane systems. These new urethane acrylates were formulated into sprayable UVcurable coatings with properties that rival two-component urethanes. The influence of diluent monomer type and content, hydroxy acrylate, and solvents on coating viscosity, VOC content, and properties were evaluated.