Pull-off forces for adhesive tapes

Abstract : An analysis is given of the force F required to pull an adhesive tape of unit width away from a rigid substrate in terms of the strength G sub a of adhesion, the tensile modulus E of the tape, and its thickness t. Measurements are reported for several commercial adhesive tapes and compared with the predictions of the theory. Excellent agreement is obtained, suggesting that the theory is basically correct. Attention is drawn to the unusual form the dependence of the failure force F upon the work G sub a of detachment and the resistance Et of of the tape to stretching in this case: F(4) variation Et G sub a(3). Even though the tape is assumed to be linearly-elastic, the markedly non-linear (cubic) relation between force F and displacement delta of the tape away from the substratee leads to this unusual result. Differences observed in G sub a from pull-off and from 90 deg peeling experiments are tentatively attributed to additional energy losses in the latter case due to the severe bending deformations imposed on the tape as it is peeled away. Keywords: Detachment, Fracture energy, Fracture mechanics, Peeling, Separation, and Strength.