Adhesives

The product designer or engineer generally has the option of an acrylic, natural or synthetic rubber, or a silicone water-, solvent-based or hot melt adhesive.

To function optimally, an adhesive should have good adhesion, or physical (and sometimes chemical) bonding of one material to another because of a variety of possible molecular interactions between the substrate surface and the adhesive. It should also have good cohesion, or internal strength, as a result of a variety of molecular forces within the adhesive itself, including chemical bonds, entanglements due to high molecular weight, intermolecular interactions, and mechanical adhesion.

 

Adhesive plasters  Fiberglass self-adhesive mesh  Rolls of color PVC plastic tape 


Although the characteristics of a tape’s adhesive can be formulated to activate upon exposure to heat or solvent, most often their needed catalyst is just pressure. Customarily, firm and even pressure during application increases bond strength. From this point, the ultimate bond strength may take between a few minutes and 72 hours to be reached. Most often, however, bonded parts can be handled immediately.

 

Materials and surface conditions

Stresses on the substrate and bond

Environmental conditions

Thin bonding

Thick bonding