Effect of Peel Angle Upon Peel Force

Measurements of peel force P per unit width are reported for samples of three adhesive tapes, adhering to two different substrates. In all cases, the work of detachment per unit area of bonded interface was found to depend upon the angle θ of detachment, increasing as θ increases. This effect is attributed to dissipation of energy in bending the tape away from the substrate at the line of detachment, to a greater degree as θ increases. Extrapolation to θ = 0 is suggested as a simple way of minimizing contributions to the observed work of detachment that arise from bending an imperfectly-elastic adhering layer as it is peeled away from a flat rigid substrate. But at small peel angles the tape tends to stretch appreciably. Peeling at 45° is recommended to minimize both effects.