React PCA-501 is a curing agent suitable for the production of exterior durable polyester powder coatings. It has the characteristics of low toxicity, no irritant to skin. good weather durability etc. The chemical structure of React PCA-501 is polyhydroxyalkyl amide. PCA-501 based powder coatings that gave improvements in the following areas: - Optimization of chemical reactivity - Improved flow and levelling - Improved degassing and film smoothness - Higher film build capability