Studies on the modification of thermoplastic polyolefins (TPOs). II. Effect of processing conditions on the morphology and adhesion of two components (2K) polyurethane coatings to the modified TPOs

The morphology of thermoplastic polyolefins (TPOs) has a profound effect on their paintability. Paint molecules can penetrate an amorphous surface easier than a crystalline one. The effects of the compression molding processing conditions, such as molding temperature and cooling rate, on the crystallinity of TPOs were investigated. The effect of crystallinity on the adhesion properties of TPOs was evaluated using a two-component solvent-based polyurethane coating. The adhesion of the coating was better for the panels with less crystallinity. The compression molding temperature was found not to have a significant effect on the crystallinity of TPOs. The cooling rate was found to have a profound effect on the crystallinity and as a result on the paintability of modified TPOs.