Improvement of paint adhesion to a polypropylene bumper by plasma treatment

Abstract

Improvement of the paint adhesion to a polypropylene (PP) bumper has been investigated without using a primer by treating the bumper surface with O2, H2O, and acetylene plasmas. All the plasma treatments resulted in an increase of the adhesion strength in dry conditions. The adhesion strength could be increased up to a value comparable to that obtained by applying a primer. The treated surfaces were quite stable for 7 days in air. After exposure to wet conditions, however, the adhesion strengths for both O2 and H2O plasma-treated samples decreased significantly, while the adhesion strength for the acetylene plasma-treated sample did not change much.