Adhesion by EB-irradiation between Laminated Sheets of Fluororesin and Polyurethan

Two layer Fluororesin/PU laminated sheets of fluororesin and polyurethane (PU) were prepared by a double-step treatment consisting of applying low dose ≦ 0.65 MGy homogeneous low energy electron beam irradiation (HLEBI) to the 2-layer assembly where the HLEBI penetrates through the fluororesin and PU layers, respectively, prior to hot-press under 5 MPa and 403 K. Although the adhesion of the Fluororesin/PU sheets cannot be observed without the double-step treatment, bonding forces were created as evidenced by the mean adhesive forces of peeling resistance ( o F p ). An increasing trend in o F p occurs by the double-step treatment applying HLEBI up to 0.43 MGy, improving the safety level without radiation damage. When HLEBI cuts the chemical bonds and generates dangling bonds with nonbonding electrons in fluororesin and PU, the created adhesion between the laminated sheets can be explained. Based on surface analysis of the Fluororesin/PU laminated sheets after the peeling tests, fluorine was detected on the PU peeled surface, indicating the strong chemical bonding generated by the double-step treatment.