Surface Post-Treatment

It may be necessary to further treat the substrate surface following surface pretreatment by the application of a primer or adhesion promoter. These are materials that are adsorbed strongly onto the substrate surface and that also interact strongly with the adhesive. A primer or adhesion promoter is applied to achieve one or more of the following:

  • Modify the surface energy of the substrate.
  • Promote chemical reaction between adhesive and substrate.
  • Activate the adhesive.
  • Inhibit corrosion of the substrate.
  • Protect the surface after pretreatment.

Organo-functional silanes, for example 3-aminopropyl trimethoxysilane, are widely used to improve adhesion. The silane substituent at one end reacts with hydroxyl groups on the surface to give a polysiloxane polymeric layer. The organic substituent on the other end reacts with the adhesive providing a covalent link.