Creation of Adhesive Force between Laminated Sheets of Aluminum and Polyurethane by Homogeneous Low Energy Electron Beam Irradiation Prior to Hot-Press

Abstract

2-layer aluminum/polyurethane (Al/PU) laminated sheets were prepared by a new adhesion method, a double-step treatment consisting of: (1) applying low dose ≦ 0.43 MGy homogeneous low energy electron beam irradiation (HLEBI) to the 2-layer assembly where the HLEBI penetrates through the Al and PU layers, respectively, prior to: (2) hot-press under 5 MPa and 403 K. Although the adhesion of the Al/PU sheets cannot be observed without the new double-step treatment, bonding forces were created as evidenced by the mean adhesive forces of peeling resistance (^oF_p). Based on the 3-parameter Weibull equation, the lowest ^oF_p value at peeling probability (P_p) of zero (F_s) could be estimated. An increasing trend in F_s occurs by the double-step treatment applying HLEBI up to 0.22 MGy reaching a maximum at 34.0 Nm⁻¹, improving the safety level without radiation damage. When HLEBI cuts the chemical bonds and generates dangling bonds with nonbonding electrons in Al and PU, the created adhesion between the laminated sheets can be explained.