粘着剤のはく離強度測定に及ぼす基材厚さの影響

抄録

The interface strength of adhesive film measured by Peel test is determined by subtracting energy consumed for plastic deformation of substrate film from external work for peeling. The film and adhesive layer are conventionally regarded to be linear elastic for easy calculation, but thinner film of 100 μm may cause plastic deformation during peeling. The film deformation might be also affected by viscoelastic property of adhesive layer since thickness of adhesive layer is no longer negligible. In this study, the interface strength was evaluated by modifying conventional elastic model to consider viscoelastic behavior of adhesive layer. Stress in adhesive layer was calculated as a function of strain and strain rate, and the corresponding deformation of substrate film was computed by finite element method. The film deformation was compared with one obtained from conventional elastic model in terms of film thickness. The interface strength was also obtained from directly observing peel shape using high speed camera to validate the proposed model. As a result, it was found that the film deformations were all similar when the film was thick, but proposed model more accurately reflected the influence of peeling rate in the thin film. Furthermore, decrease in interface strength was confirmed for thinner film at faster peeling rate.