Should we be concerned about shrinkage of our adhesives on curing?
Some adhesives, such as solvent-based materials and latex adhesives, always shrink as the carrier evaporates or is absorbed by the substrates. However, even 100% solid adhesives can have considerable shrinkage on curing. Shrinkage occurs because the density of the polymer is higher than that of the monomers (e.g., epoxies or acrylics). Different adhesive types have different levels of shrinkage; for example, epoxies typically shrink in the 2-5% range, whereas shrinkage of unmodified acrylics can be much higher. A worst-case scenario is adhesives and sealants with very high levels of multifunctional acrylate or methacrylate monomers, where shrinkage can be over 10%.