INVESTIGATION OF THE SURFACE AND INTERPHASE COMPOSITION OF ADHESION PROMOTER THERMOPLASTIC OLEFIN SYSTEMS - THE EFFECT OF ADHESION PROMOTERBAKE TEMPERATURE

The interfacial chemistry of model systems consisting of two adhesion promoting primers and a single Thermoplastic Olefin (TPO) substrate wa s examined. Two commercial adhesion promoter (AP) materials were appli ed to a commercially-available TPO material and either flash dried at room temperature or baked at 100 degrees C. The surface composition of the AP films and TPO substrate, and the interfacial compositions of t he AP/TPO systems were characterized using x-ray photoelectron spectro scopy (XPS). The AP films studied were based upon a chlorinated polyol efin (CPO). For one adhesion promoter film (AP-I), no chlorine was pre sent at the surface suggesting a nonhomogeneous system. For the second adhesion promoter film (AP-2), the surface composition was about 15% CPO and 85% AP matrix. No changes in AP surface composition were evide nt for the different bake conditions for either AP. Interfacial compos itions of the room temperature flashed materials were found to be very similar for both AP/TPO systems, with CPO being present for each and at similar concentrations. Interfacial compositions for the baked mate rials were also similar for the two systems, although the level of CPO at the interface increased for both the AP-1 and AP-2 relative to the unbaked materials. The relative increases observed were 46% and 41% f or the AP-1 and AP-2 systems, respectively. The increase in the relati ve concentration of CPO at the interface with bake temperature suggest s that there is a stronger interaction between the AP and TPO. The imp lication of these data is that a baked AP should result ih a more robu st paint system with respect to AP/TPO adhesion.