Modern adhesives fall into three broad categories. Let’s take a look:
Solvents are solutes – substances that dissolve other substances, creating a liquid solution. Solvent-based adhesives contain polymers in a solution form. Once applied, the solvent evaporates and as it does so, the glue hardens in place to create a bond.
Also known as dispersion adhesives, water-based adhesives are supplied either in solution form or as dry powders for mixing with water. When the water evaporates or is absorbed by the surface to which it has been applied, the remaining water-soluble polymers, dispersed by the liquid, coagulate into an adhesive bond.
Common water-based adhesives include:
- White school glue
- Latex glue
- Starch glue
Polymer glue is also known as emulsion adhesive. Typically milky-white in colour, it is made from powerful bonding polymers such as polyvinyl acetate (PVA). Polymer-based adhesives are sensitive to heat, melting at certain temperatures and setting again once they have cooled. They are ideal for use when glueing wood.