Contact adhesives are probably the best known of the solvent-based adhesives. They bond by a diffusion process sometimes referred to as autohesion. Contact adhesive formulations are prepared from an elastomeric polymer carried in solvent solution or in water as a latex. The base polymer is generally polychloroprene, but polyurethane, styrene butadiene rubber, and acrylic polymers are also employed.
Contact adhesives are widely used because of their easy application, fast setting properties, and excellent adhesion to many different substrates. The contact adhesive is coated on both surfaces to be joined. After the carrier evaporates, the two surfaces are brought together under slight pressure, and the adhesive bonds to itself. The surfaces can also be heated to speed drying time and to increase tack. A high degree of handling strength occurs immediately, and the joint strength increases further with time.
This article will review the processes by which contact adhesives adhere.