What is the primary characteristic of solvent-based adhesives?

The primary characteristic of solvent-based adhesives is that they harden or cure as the solvent evaporates. This process involves the adhesive initially being in a liquid form, which allows it to be easily applied to surfaces. Once applied, the solvent gradually evaporates, resulting in a hardened bond.

However, while solvent-based adhesives can form strong bonds, they are typically not suitable for load-bearing applications because their adhesion strength may not meet the demands of heavy loads or structural applications. The cure time can vary based on the type of solvent used and the environmental conditions, but they do not require constant heating to remain effective, which distinguishes them from other adhesive types like hot melt adhesives that need heat to remain in a liquid state. The strength comparison with hot melt adhesives can also vary depending on specific formulations and applications, but saying solvent-based adhesives are universally stronger than hot melt adhesives is not accurate.

This understanding of the nature and behavior of solvent-based adhesives is crucial for choosing the right adhesive for specific engineering applications.