Functional Powder Coatings Via Isocyanate-Cured Phenolics

By Weih Lee, Robert Polance, Hart Haugen

In this work centering around phenolic chemistry, we investigated isocyanate and benzoxazine-modified phenolic powder coatings for use in anti-graffiti applications and for addressing downhole drill pipe interior coating challenges. Allied polyurethane formulations were developed using phenolic hydroxyl- isocyanate reactions and shown to outperform conventional aliphatic polyol-isocyanate coatings for graffiti-resistant applications.

Effects of variables like phenol hydroxyl equivalent weights and molecular weights of phenolic resins were examined. In a separate effort intended for oil and gas downhole pipe interior lining applications, novel fusion-bonded benzoxazine-epoxy-phenolic formula-tions, without or with an acid catalyst, exhibited excellent adhesion, toughness, and process-ability, in addition to greatly reducing cure requirements as compared to benzoxazine self-polymerization.

Applicable rheology and kinetics of cure were quantified, revealing characteristic flow and cure behaviors to strengthen the understanding of structure-property relationships and to facilitate efficient optimization of coating performance.