Selection of Adhesives

Abstract

Selection of the correct adhesive for an application can be a daunting task due to the many types commercially available, ranging from different chemistries through different forms to almost a continuum of material properties. It is critical therefore to take a logical approach to this task and apply deselection criteria wherever possible. The needs of the final application are paramount and often a detailed review of the requirements can provide the engineer with some key selection needs or constraints which in turn may enable large groups of adhesives to be eliminated from consideration at an early stage in the process. It is also important to appraise aspects related to manufacturing, in terms of product volume, handling issues, curing equipment, dispensing equipment, etc. An apparently perfect adhesive with suitable mechanical properties may not be suitable for the application for one or more reasons such as not being able to be dispensed easily/rapidly enough, having a curing temperature that is too high for the substrate to tolerate, curing too fast for a large area joint etc.

Although the initial adhesive selection process is “only” a desktop exercise, the need to be efficient and identify only those candidates with the greatest property match requires that this activity be given a high level of importance. Almost every application will require a bespoke approach at some level and this will necessitate practical testing and trials to be carried out to verify suitability. Selection of unsuitable adhesives at the outset can be very costly in the long run.