Abstract
A novel over coating layer (OCL) was prepared by blending acrylic copolymer and epoxy compound. The OCL material showed a long shelf life at room temperature, but it clouded during post-baking process. The mechanism of the clouding was investigated by NIR, SEM, and AFM. NIR was the especially useful method to follow the reaction between acrylic copolymer and epoxy compound. Through these measurements, it was confirmed that the final reaction extent of the OCL containing palmitic acid was higher than that of the OCL without the acid. The carboxylic acids with a long alkyl group such as palmitic acid reduced the phase separation between the acrylic copolymer and epoxy compound at post-baking process, and resulted in a long shelf life and clear surface condition of the OCL.
