Often one requires a bond or an adhesive that is not permanent, and the adhesive joint needs to be "debonded" at a predetermined time. Uses for nonpermanent adhesives include nonstructural applications such as removable labels, surface protection films, easily placeable and removable notepaper, and bonding credit cards to mailers, as well as structural applications such as tooling placement, prototyping, disassembly of parts for reuse, and repositioning.
Although the conceptual understanding of permanent and removable adhesives is clear, the functional definition and classification of such materials is not so simple. Permanence and removability is a subjective evaluation that can vary from person to person and from application to application.
This paper will discuss the requirements of "removable adhesives" and review some of the materials and formulation concepts that are being employed to develop such state-of-the art "designer" adhesives. The focus will be on pressure sensitive adhesive systems because of their popularity and common usage, but other adhesives will also be discussed.