Polycaprolactone (PCL) polyols are used to enhance coatings that feature other polymer chemistries in both 1K and 2K coatings. Polycaprolactone polyols are low viscosity and 100% non-volatile, enabling high-solids and ultra-low-VOC coatings. The unique chemistry of these polyols promotes their use in numerous coating applications and on a variety of substrates. This article explores the performance benefits achieved when low-molecular-weight PCL tri- and tetra-functional polyols are blended with other hydroxyl-functional polymers in 2K coatings.
Polyurethane coating technology is well known for its high performance and versatility in thermosetting coating applications. Two-component (2K), solventborne polyurethane (PU) coating systems typically consist of an ‘A’ pack, which contains hydroxyl-bearing polymers (commonly referred to as “polyols”), along with a ‘B’ pack, which contains a polyisocyanate crosslinker. The polyol resin often contains solvent to help the formulator achieve reasonable application viscosities. One common polyol chemistry used is polyacrylic polyols, which can provide a coating with desirable properties such as weatherability, gloss retention, and hardness. Low-molecular-weight polycaprolactone (Capa®) polyols, at 100% solids, can be added to a coating formulation alongside polyacrylate polyols in a 2K-PU coating system to help improve properties such as flexibility and low-VOC levels. Two-component-PU topcoats consisting solely of an acrylate hydroxyl bearing binder, are often low in flexibility, yielding brittleness, which in turn can negatively affect the longevity of a coating in harsh environments.