Mechanistic model for the stress-strain response of double-layered PSA

Abstract

Experiments and modeling are used to understand the mechanics of the deformation mechanisms in double-layers pressure sensitive adhesives (PSAs). The mechanical role of the carrier layer and the resulting stress state in a double-layered pressure-sensitive adhesive (PSA) system, as shown in Figure 1, is presented in this paper. This description of the deformation mechanism is developed based on empirical results of stress-strain response of double-layered PSA-bonded assemblies and in-situ observation of the deformation of carrier layer during the debonding process. This study of double-layered PSAs, is motivated by the fact that there are currently very few studies in the literature regarding the mechanics behind the secondary transition observed in the stress-strain and creep responses of PSA-bonded assemblies. Empirical observations verify that this behavior is due to sequential cavitation and fibrillation in two adhesive layers caused by the new bonding interface introduced by the carrier layer. The effect of carrier thickness and strength of adhesion between PSA and substrates on the stress-strain response of double-layered PSA systems is also important. In-depth, physics-based understanding of the relationship between flexural rigidity of carrier layer and stress-strain performance of PSA-bonded assemblies will help to optimize the design of double-layered PSA joints for a given substrate material. The modeling tasks in this paper use finite element analysis is to understand the effects of carrier layer stiffness on the stress-strain response of PSA bonded assembly. Conclusions from this study will be applied to generate semi-analytic mechanistic models for modeling the stress-strain behavior of double-layered PSA joints. This modeling approach will be an enhancement of earlier model presented for single-layered PSAs [1].