Some aspects of UV curable coatings on plastic substrates

The coatings of polycarbonate sheets with UV curable systems based on an epoxy acrylic res in the presence of different reactive diluent were investigated. A correlation was observed between the capacity to dissolve the polycarbonate and the adhesion on the plasic substrate. The adhesion is influenced by the diffusion of the monomer of the coating into the polycarbonate substrate. FTIR-ATR spectra support this meechanism. Analyses show the presence of glass transition typical of the two phases. In the case of good adhesion on the plastic substrate the presence of a transition layer between the two phases is indicated.